Bacteriology Flashcards by Kamel Caragay

Belong to the Protista kingdom
Include some eukaryotes, prokaryotes, viruses, viroids, prions
Classified according to structure, chemical composition, and biosynthetic and genetic organization

Microorganisms

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Organ of locomotion for prokaryotes

Flagella

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Organ of locomotion for eukaryotes

Flagella and pseudopodia

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Cell wall less bacteria

Mycoplasma
Ureaplasma

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Fungal cell membrane

Ergosterol

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Provides shape to bacteria

Cell wall

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In bacteria, energy production happen in

Cell membrane

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Not cells, not visible to light microscope

Viruses

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Bacterial viruses

Bacteriophages or phages

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Single-stranded, covalently closed, circular RNA molecules that exists as base-paired, rodlike structures
Cause plant diseases

Viroids

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RNA of the hepatitis D virus is ____

Viroid-like

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Abnormal proteins

Prions

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Infectious particles associated with subacute progressive, degenerative diseases of the CNS (Creutzfeldt-Jacob Disease)

Prions

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Alter conformations of a normal cellular protein that autocatalytically form more copies of itself.

Prions

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Spiral Sjape

Spirochetes
Borrelia
Leptospira
Treponema

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Straight rod or with single rigid curve

Vibrio

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Rigid helical rod

Spirillium

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Flesuous helical rod

Spirochete

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Vary in size and shape

Pleomorphic
ex: Bacterioides, Mycoplasma, Ureaplasma

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Example of antibiotic that affect cell wall biosynthesis and may alter a bacteria’s shape

Penicillin

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Coffee-bean shaped diplococci

Neisseria

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Lancet-shaped diplococci

S. pneumoniae

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Palisades

Corynebacterium

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Smallest pathogenic bacillus

Haemophilus

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Largest pathogenic bacillus

Bacillus anthracis

Mucilaginous envelop that surrounds some bacteria (if present, considered as virulence factor)

Capsule

Structure surrounding a bacterial cell and is external to the cell wall

Polysaccharide

Bacteria without polysaccharide, instead possess poly-D-glutamic acid capsule

Bacillus anthracis

Property of capsule that may increase virulence by preventing phagocytosis

Immunoevasion

Basis of serotying by Quelling reaction: specific capsular swelling with type-specific antiserum

Antigenic

Encapsulated organisms

"Some Nasty Killers Have Some Capsule Protection" Streptococcus pneumoniae Neisseria meningitidis Klebsiella pneumoniae Haemophilus influenzae Salmonella typhi Cryptococcus neoformans Pseudomonas aeruginosa

Special staining methods

Hiss stain India ink stain

Loosely arranged extracellular material that surrounds bacterial cells

Slime layer

Found in biofilms

Slime layer

Used by some bacteria to adhere to surfaces like catheters (S. epidermidis)

Biofilm

Organized layer

Capsules

Also known as the peptidoglycan later or murein layer

Cell wall

Functions of _____ Protects bacteria against osmotic pressure Gives shape to the bacteria Confer the gram reaction of the bacteria Usual target of anti-microbial drugs (penicillins, cephalosporins)

Cell wall

Thicker, teichoic acid

Gram-positive cell wall

Composed of a very thick protective peptidoglycan (murein) layer

Gram-positive cell wall

G+ cell wall consists of glycan chains of alternating ___ and ___

NAG and NAM

Negatively charged and contributes to the negativity of the cell wall

Teichoic acid

It may also bind and regulate the movement of cations into and out of the cell

Teichoic acid

Have an outer membrane

Gram (-) cell wall

Composed of a thin layer of peptidoglycan, No teichoic acid

Gram - negative cell wall

Between outer membrane and gram negative cell wall

Periplasma space

Has a gram positive reaction

Acid-fast cell wall

Concurs resistance to drying and chemicals

Acid-fast cell wall

Contain a waxy layer of phospholipids and fatty acids (hydroxymethoxy acid or mycolic acid) bound to the exterior of the cell wall

Acid-fast cell wall

Acid-fast organisms

"No MILC" Nocardia Mycobacterium Isospora Legionella micdadei Cryptosporidium

Other clinically relevant organisms with cell wall containing mycolic acid

Nocardia Rhodococcus Gordonia Tsukamurella Corynebacterium

Bacteria without cell walls contain ___

Sterols

Examples of bacteria without cell wall

Mycoplasma, ureaplasma

Present only in gram-negative bacteria

outer membrane

Composed of proteins, phospholipids, and lipopolysaccharide

Outer membrane

Lipopolysaccharide is comprised of:

Lipid A Core polysaccharide O polysaccharide

Vital to evade the host defenses; it contributes to the negative charge of the bacterial surface

Lipopolysaccharide

It comprises endotoxin

Lipopolysaccharide

Essential component of both Gram pos and gram neg bacteria

Cell membrane

Has affinity for basic dyes

Metachromatic Granules

Site of bacterial energy metabolism

Cell membrane

Special stains for metachromatic granules

Albert Neisser Ponder Methylene Blue

Babes Ernst Granules

Corynebacterium diphtheriae "Corny mo, Babe"

Much granules

Mycobacterium tuberculosis

Bipolar granules

Yersinia pestis "Safety pin appearance"

Function as a survival response to certain adverse nutritional conditions, such as depletion of a certain source

Endospore

Highly resistant to desiccation, heat, and various chemicals The last structure to be destroyed

Endospores

Basis of QC in autoclaving

Endospores

Endospores are helpful in identifying some species of bacteria like

Bacillus and Clostridium

Terminal spore

Clostridium tetani

Subterminal spore

Clostridium botulinum

Central spore

Bacillus anthracis

Boxcar appearance

Bacillus anthracis

Possess a core that contains many cell components, a spore wall, a cortex, a coat, and an exosporium

Endospore

The core of endospore contains ____, which aids in heat resistance within the core

Calcium dipicolinate

Endospore stains

Schaeffer-Fulton stain (green) Doemer's stain Wirtz-Conklin

True or False. Endospore germinate under favorable nutritional conditions after an activation process that involves damage to the spore coat. They are not reproductive structures

True

Gives motility to bacteria. For locomotion

Flagella

No flagella

Atrichous

Single flagellum at each pole

Monotrichous

Examples of Monotrichous

Vibrio Campylobacter Helicobacter Pseudomonas aeruginosa NO Enterobacteriaceae are monotrichous

Single flagellum at each pole

Amphitrichous

Tuft of flagella at one or both poles

Lophotrichous

Flagella all over organism

Peritrichous

Examples of Peritrichous

Enterobacteriaceae, except SKY (Shigella, Klebsiella, Yersinia)

Most common flagella in pathogens

Peritrichous and monotrichous

Demonstrate motility at ____ hours growth

Often, motility can be best seen at ____

25 deg C (35-37 deg C may be inhhibitory)

Component of flagellar stains

Tannic acid

Examples of flagellar stains

Leifson Fisher and Conn Gray

Precipitates and coats flagella

Tannic acid

AKA axial filament Found in spirochetes

Endoflagella

Tumbling motility

Listeria monocytogenes

Darting motility

Campylobacter

Gliding motility

Capnocytophaga

Swarming motility

Proteus

Hair-like extensions that extent into the environment

Pili/Fimbrae

Type of pili that serves as an attachment

Common pili

Pili for conjugation

Sex/conjugate pili "bacterial sex"

Bacteria reproduce by asexual reproduction via

Binary fission

4 phases of the growth cycle

Lag phase Logarithmnic/exponential phase Stationary phase Decline and death

Little or no multiplication but enzymes are very active. A period of adjustment and adaptation

Lag phase

Organisms grow at maximum rate (exponential rate). Most sensitive to antimicrobials

Logarithmic phase

Plateau-growth ceases because nutrients are exhausted or toxic metabolic products have accumulated

Stationary phase.

Direct microscopic count may remain constant but viable count slowly decreases

Decline and death

3 mechanisms of bacterial gene transfer

1. Transformation 2. Conjugation 3. Transduction

Direct uptake DNA from surrounding environment -Allows evolution of DNA over time -Introduce genes to bacteria for replication

Transformation

Transfer from one cell to another via pillus; requires physical contact of 2 organismsm -DNA transferred via plasmids

Conjugation

Small DNA molecules within a cell

Plasmids

Transfer of DNA via a bacteriophage (virus that infects bacteria)

Transduction

Nuclear material enters bacteria -Multiplies, lyses cells -Releases progeny viruses

Lytic cycle

Nuclear material enters cell -Incorporates in host DNA -May later become excised then enter lytic phase -Genes for some bacterial toxins are transferred to non-toxic strains via lysogeny

Lysogenic cycle

Phages that replicate only via the lytic cycle

Virulent

Phages that replicate using lytic cycle and lysogenic cycle

Temperate

"jumping genes" DNA segments within bacterial DNA

Transposons

A mechanism of transfer of resistance to antibiotics; can even transfer antibiotic resistance genes between 2 different bacterial species

Transposition

Require preformed organic compounds for growth, includes most medical important bacteria

Heterotrophs/Organotrophs

Do not require preformed organic compounds for growth because they can synthesize them from inorganic compounds and carbon dioxide

Autotrophs/Lithotrophs

Use light as energy source

Phototrophs

Use redox potential generated by various chemical reactions

Chemotrophs

Grows in the presence of atmospheric (free) oxygen)

Aerobe

Cannot grow in the absence of free oxygen, which serves as final electron acceptor. Contain superoxide dismutase, which protects from the toxic oxygen

Obligate aerobe

Requires reduced amount of free oxygen (5% O2)

Microaerophile

Grows in the absence of atmospheric oxygen

Anaerobe

Cannot grow in the presence of atmospheric oxygen; lack superoxide dismutase, catalase, and cytochrome-C oxidase (enzymes that destroy toxic products of oxygen metabolism) Use nitrates, sulfates, and carbonates as final electron acceptor

Obligate anaerobes

Fundamentally an aerobe but can grow in the absence of atmospheric oxygen

Facultative anaerobe

Does not grow well, but survives in the presence of atmospheric oxygen

Aerotolerant

Obligate Aerobes

Mycobacterium Corynebacterium P. aeruginosa Nocardia Bacillus "May Cash sa PNB"

Obligate Anaerobes

Actinomyces Bacteroides Clostridium Fusobacterium Eubacterium Prevotella

Aerotolerant

Lactobacillus Propionibacterium

Microaerophiles

Campylobacter Helicobacter

Facultative anaerobe

Most pathogenic bacteria are facultative anaerobes

Growth of obligate aerobes in thioglycollate broth

growth at the top

Growth of facultative anaerobes and aerotolerant anaerobe in thioglycollate broth

growth all throughout

growth of obligate anaerobe in thioglycollate broth

growth at the bottom

Growth enhanced by the increased CO2 (5-10% CO2)

Capnophile

Capnophiles

Streptococcus Campylobacter Haemophilus Helicobacter Moraxella catarrhalis Mycobacterium Pathogenic Neisseria "Sa Camp Here in Heaven, May Money Po!"

Grow below 10 deg C Ex: L. monocytogenes , blood bank contaminants

Psychrophilic

Grow at 20 - 40 deg C (best at 30 - 37 deg C). Most pathogens

Mesophilic

grow at 50 -55 deg C (basis of test for effective autoclaving

Thermophilic

Specimen is placed in the refrigerator -inhibits growth of bacteria except L. monocytogenes and Y. enterocolitica

Cold enrichment technique

Lactobacillus grows in a special medium called __

Tomato juice agar

Vibrio species are alkalophiles and grows in ___

Alkaline Peptone Water: enrichment medium and TCBS: differential medium

total absence of viable microorganisms as assessed by no growth on any medium

Sterility

kills bacteria

Bactericidal

inhibits growth of bacteria

Bacteriostatic

removal or killing or all microorganisms

sterilization

removal or killing of disease-causing microorganisms (inanimate objects)

Disinfection

any procedure that inhibits the growth and multiplication of microorganisms

Antisepsis

Method of sterilization and disinfection that coagulates protein

Moist heat

100 deg C for 15 - 30 minutes -kills all vegetative organisms but not all spores or viruses

Boiling

Alternate heating (kills vegetative cells), incubation (spores germinate), heating

Fractionation

Flowing steam for 30 minutes on 3 successive days

Tyndallization

75 - 80 deg C for 2 hours on 3 successive days

Inspissation

Used to sterilize media containing milk or serum

Fractionation

Uses steam under pressure 121 deg C at 15 psi for 15 - 30 minutes

Autoclaving

Most effective method of sterilization

Autoclaving

Used to raise temperature in autoclaving

pressure

Kills organisms including viruses and spores; Used whenever possible to sterilize liquid media, instruments, glassware

Autoclaving

Quality control in autoclaving

spores of Bacillus stearrothermophilus incubated at 56 deg C

recommended for milk and dairy products

Pasteurization

Low temperature holding 63 deg C for 30 minutes

Batch pasteurization

High temperature short time at 72 deg C for 15 seconds

Flash Pasteurization

Kills by oxidation

Dry heat

Temp and duration for oven using dry heat

160 - 180 deg C for 1 -2 hours

Quality control of dry heat

spores of Bacillus subtilis incubated at 35 - 37 deg C

To sterilize inoculating loop

Flame

Size of membrane filter that has 100% bacterial sterility

0.22 um

For urea broth and sugar fermentation broth

Filtration

UV light

Radiation

Cold sterilization Used for materials that cannot be autoclaved

Ethylene oxide gas

Quality control for ethylene oxide gas

spores of Bacillus subtilis incubated at 35 - 37 deg C

Destroys vegetative forms on inanimate objects

Disinfectant

denature proteins; activity reduced by organic matter (cresol less affected)

Phenolics

Inactivate bacteria by binding with their hydrophobic and lipophilic groups, interacting with the cell membrane to alter metabolic properties and permeability

Quaternary ammoniums (quats)

oxidizes organic matter

Chlorine

safe for delicate lensed instruments; usually poor activity against Pseudomonas

2% aqueous glutaraldehyde

a dipheyl cationic analog that is useful for topical disinfectant

Chlorhexidine

5 types of disinfectants

1. Quaternary ammoniums 2. Phenolics 3. Chlorine 4. 2% aqueous glutaraldehyde 5. Chlorhexidine

Phenol is used as a disinfectant standard that is expressed as a ___. This compares the rate of the minimal sterilizing concentration of phenol to that of the test compound for a particular organism

phenol coefficient

The endpoint of phenol coefficient is the lowest concentration that kills test organisms in ___

10 minutes at 20 deg C

Test organisms for phenol coefficient

Salmonella typhi and Staphylococcus aures

agent used on living tissue

antiseptic

3 types of antiseptics

1. Alcohol 2. Tincture (alcoholic) iodine 3. Iodophor

__ is necessary for protein denaturation

Water

___ is the major form of alcohol used in hospitals

Isopropyl alcohol (90-95%)

Tincture (alcoholic) iodine is composed of:

2% solution of aqueous alcohol containing potassium iodide

Iodophor is composed of:

Iodine + detergent (e.g. povidone-iodine)

Biologic indicators 1. Autoclave: 2. Ionizing radiation: 3. Dry heat oven: 4. Ethylene oxide:

Biologic indicators 1. Autoclave: Bacillus stearothermophilus 2. Ionizing radiation: Bacillus pumilis 3. Dry heat oven: Bacillus subtilis var niger 4. Ethylene oxide: Bacillus subtilis var globigii

Designed to protect the operator, the laboratory environment, and work materials from exposure to infectious aerosols and splashes that may be generated when manipulating materials containing infectious agents

Biological safety cabinets

Open front BSC. Has HEPA filter. Filtration happens once. Provides minimal personnel protection. Does not protect work surface

Class I BSC

Laminar flow cabinets with variable sash opening. Filtration happens twice. Most commonly used in hospital micro labs. Provides protection for worker and work surface

Class II BSC

Completely enclosed. Negative pressure. has gloves. Provides maximum protection

Class III BSC

Biosafety level not known to cause disease in healthy adults

Level I

Biosafety level: common pathogens

Level 2

Biosafety level: causes serious lethal disease via inhalation. Effective treatment available

Level III

Biosafety level that causes life-threatening disease. No vaccine

Level IV

Found in the cell wall of S. aureus -inhibits phagocytosis by binding Fc portion of IgG

Protein A

Enzymes that cleave IgA, allows colonization of mucosal surfaces -produced by S. pneumoniae, H. influenzae, N. gonorrhoeae, N. meningitidis "SHiNe"

IgA protease

Found as a surface molecule of group A streptococcus, prevents phagocytosis

M protein

Only in gram neg bacteria -lipopolysaccharide -released when bacteria die -heat resistant

Endotoxin

Like LPS but lacks O antigen Endotoxin activity Found on non-enteric gram negs (N. meningitidis is most important example)

Lipooligosaccharide

Sore throat with membrane, swollen nodes -Inactivates elongation factor (EF-2), which is necessary for protein synthesis.

Corynebacterium diphtheriae

Causes many types of infection (skin infections, sepsis, pneumoniae) -same mechanism as diphtheria toxin

Pseudomonas aeruginosa (Exotoxin)

Causes infectious diarrhea -invasion of GI mucosal cells is still the main cause of diseases; -nontoxigenic strain causes significant disease

Shigella (Shiga toxin)

Strain of E. coli that produce "shiga-like" toxin; Typically cause bloody diarrhea -can also cause hemolytic uremic syndrome (HUS) when toxin reaches system circulation -Classic serotype is E.coli O157:H7

Enterohemorrhagic E. coli (EHEC) Shiga-like toxin

aka Traveller's diarrhea -causes watery diarrhea

Enterotoxigenic E. coli (ETEC) Heat labile toxin (LT) Heat stable toxin (ST)

3 proteins of Anthrax

Protective antigen (PA) Lethal factor (LF) Edema factor (EF)

2 proteins of B. anthracis that causes edema toxin

Protein antigen Edema factor

Causes "rice-water" diarrhea that leads to dehydration, electrolyte losses, and shock

Vibrio cholerae (Cholera toxin)

Causes whooping cough

Bordetella pertusis

Preferred specimen for the determination of Bordetella pertusis (whooping cough)

Nasopharyngeal swab

Works in spinal cord (Renshaw cells) - results in spastic muscle paralysis

Clostridium tetani (Tetanospasmin)

Works at neuromuscular junctions -results in muscles floppy (Flaccid paralysis) -In babies: Floppy Baby Syndrome ( contaminated honey)

Clostridium botulinum (Botulinum toxin)

Causes Gas Gangrene Phospholipase C enzyme

Clostridium perfringens (Alpha toxin)

"Cytolysin" (lysis cells) -Responsible for beta hemolysis -Trigger production of anti-streptolysin O (ASO) -Can be usefu lin suspected rheumatic heart disease or post strep glomerulonephritis

Streptococcus pyogenes (Streptolysin O)

Activate a MASSIVE number of T-cells (2-20% T cells)

Superantigens

2 examples of superantigens

TSST-1 (S. aureus) Pyrogenic exotoxin A or C (S. pyogenes)

Reagents in Gram staining

1. Primary stain - Crystal Violet 2. Mordant - Gram's Iodine 3. Decolorizer - Alcohol-Acetone 4. Secondary stain - Safranin "VIAS"

Bacteria with thick cell walls containing teichoic acid retain the crystal violet-iodine complex dye after decolorization.

Gram Stain

Primary stain binds to mycolic acid in the cell walls of mycobacteria and is retained after the decolorizing step with acid-alcohol

Acid-Fast Stain

Reagents in AF Staining

1. Primary Stain - Carbol fuchsin 2. Mordant - Heat or phenol 3. Decolorizer - Acid-alcohol 4. Methylene Blue

Size of AFB smear

at least like a thumb size or 2 cm x 3cm

Fluorochrome dye that stains both gram positive and gram negative bacteria, living or dead. -Binds to the nucleic acid of the cell and fluoresces as a bright orange when fluorescent microscope is used.

Acridine Orange

Fluorochrome that binds to chitin in fungal cell walls. -Fluoresces as a bright apple-green or blue-white, allowing visualization of fungal structures with a fluorescent microscope

Calcoflour White

Traditionally has been used to stain C. diphtheriae for observation of metachromatic granules

Methylene Blue

Used to stain the cell walls of medically important fungi grown in slide culture

Lactophenol Cotton Blue

Negative stain used to visualize capsules surrounding certain yeasts, such as Cryptococcus spp

India Ink

Primary stain: malachite green (heated to steaming for about 5 minutes) Counterstain: Safranin Endospores appear green with pink-appearing or red-appearing bacterial cells

Endospore stain

Fluorescein-labeled antibodies made from antisera produced by injecting animals with whole organisms or complex antigen mixtures - Resultant polyclonal antibodies may react with multiple antigens on the organism that was injected and may also cross-react with antigens or other microorganisms or possibly with human cells in the specimen

Immunofluorescent antibody (IF) staining

IF staining is useful in confirming the presence of specific organisms such as

Bordetella pertusis or Legionella pneumophila

Percentage of agar in semi-solid media

0.5 - 1%

Percentage of agar in liquefiable solid media

2-3%

Tissue culture system from African green monkey

Vero cell

Tissue culture system from mouse cell line

Mccoy cell

Tissue culture system from Lung carcinoma

A549 cell

Tissue culture system from Cervical carcinoma

Hela cell

Tissue culture system from laryngeal carcinoma

Hep-2 cell

Supports the growth of non-fastidious organism -Nutrient agar or broth; Trypticase soy agar or broth

Simple or General Purpose

Select the growth of particular organism and prevents other organism thru inhibitors

Selective

Selective medium for Mycobacterium tuberculosis

Lowenstein Jensen

Selective medium for Gram positive microorganism

Phenylethyl alcohol

Selective media for Neisseria gonorrhea

Thayer Martin, Martin Lewis, New York City

Culture media that contains nutrient supplements

Enriched

Enriched media that contains 5% defibrinated Sheep blood (Horse/rabbit)

Blood agar plate

Enriched medium for Haemophilus

Chocolate agar plate

Preparation of Chocolate agar plate

-Add blood while base medium is still hot to lyse the RBCs -Release X and V factors

X factor

Hemin

V Factor

NAD

Can enhance the growth of microorganism

Enrichment

Enrichment medium for Vibrio

Alkaline Peptone Water

Enrichment media for Salmonella and Shigella

Selenite and Tetrathionate

Allow certain types of organisms to grow and differentiate, and inhibit the growth of other organisms

Selective-Differential

Selective-Differential medium for S. aureus and S. epidermidis/saprophyticus

Mannitol Salt Agar

Selective-Differential medium for Vibrio spp

Thiosulfate Citrate Bile Salt

Provides distinct colonial appearance of microorganisms to know their identification

Differential

Differential media that contains 3 sugars (lac, gluc, suc)

Triple Sugar Iron

Standard medium for specimens

Blood agar (usually made with 5% sheep blood)

Hemolysis with green zone around colony. May be narrow or wide. Partial lysis of RBCs

Alpha hemolysis

Complete lysis of RBCs. Clear zone around colony.

Beta hemolysis

No lysis of RBCs. No zone of hemolysis

Gamma

Examples of organisms that are alpha hemolytic

Streptococcus pneumoniae Viridians streptococci Some enterococci

Examples of organisms that are beta hemolytic

Group A strep Group B strep Listeria monocytogenes

Examples of organisms that are gamma hemolytic

Some enterococci

___ is readily identified in the laboratory by its characteristic "double zone" hemolysis also known as target hemolysis

Clostridium perfringens

Small area of intact RBCs around colony surrounded by a wider zone of complete hemolysis

Alpha-prime or wide zone hemolysis

Enriched medium that will grow most nonfastidious bacteria

Sheep blood agar

What is added to the blood agar medium to allow differentiation of hemolysis

Tryptic soy agar with 5% sheep blood

Enriched medium for Haemophilus and Neisseria. Supplies X and V factors

Chocolate agar

Selective medium for gram-positive microorganisms

Columbia colistin nalidixic agar (CNA) *CN suppress most GN

Selective medium for gram-positive cocci and anaerobic gram-negative rods

Phenylethyl alcohol agar (PEA) *inhibits enteric gram-negative rods.

Selective medium for S. pyogenes and S. agalactiae

Streptococcal selective agar (SSA) *contains trimethoprim-sulfamethoxazole

Selective differential medium for isolation of enteric gram-negative rods

Eosin methylene blue (EMB) *EM inhibit gram positives *Lactose fermenters are green-black or purple *Nonlactose fermenters are colorless

In EMB, E. coli produces ___

Green metallic sheen

Selective, differential medium for isolation of enteric, gram-negative rods

MacConkey Agar (MAC) *Bile salts and crystal violet inhibit most gram positives *Lactose fermenters are pink *Non-lactose fermenters are colorless

Selective, differential medium for E. coli O157:H7

MacConkey sorbitol agar (SMAC) *E. coli O157:H7 does not ferment sorbitol. colonies are colorless

Selective, differential medium for isolation of enteric pathogens from stool

Hektoen enteric agar (HE) *Bile salts, bromthymolblue, acid fuschin inhibit normal GI flora *Non pathogens are orange to salmon pink *Nonlactose fermenters are green to blue green *H2S positive colonies have black precipitate

Selective, differential medium for isolation of Salmonella and Shigella in stool

Xylose lysine deoxycholate (XLD) *Deoxycholate inhibits gram neg rods and gram pos

Four types of colonies in XLD

-Yellow (E. coli) -Yellow with black centers (Some Proteus spp) -Colorless or red colonies (Shigella) -Red colonies with black centers (Salmonella)

Selective medium for Salmonella and Shigella

Salmonella-Shigella agar (SS) *Brilliant green and bile salts inhibit coliforms *Salmonella and Shigella do not ferment lactose - colonies are colorless *Salmonella produces H2S

Selective enrichment medium for isolation of Salmonella and Shigella

Gram-negative broth (GN) *Deoxycholate and citrate salts retard growth of gram-positives

Enrichment broth used for recover of Salmonella from stool

Selenite broth *Subculture onto selective differential agar after 6-8 hours of incubation

Enrichment broth for recovery of Salmonella from stool

Tetrathionate broth *Bile salts and sodium thiosulfate inhibit gram positives and Enterobactericeae.

Selective enrichment medium for isolation of Campylobacter from stool

Campylobacter blood agar (Campy BAP) *Incubate pates in increased CO2 at 42 deg C

selective enrichment medium for recovery of Neisseria gonorrhoeae and Neisseria meningitidis from specimens with normal flora

Modified Thayer Martin (TM)

Antibiotics in Modified Thayer Martin (TM)

VCNT Vancomycin Colistin Nystatin Trimethoprim (inhibits swarming of Proteus)

Thayer Martin antibiotics

VCN

Selective enrichment medium for recovery of N. gonorrhoeae and N. meningitidis from specimens with normal flora

Martin Lewis

Antibiotics is Martin-Lewis

VCAT *Anisomycin - antifungal

Selective enrichment medium for isolation of N. gonorrhoeae and N. meniningitidis from specimens with normal flora

New York City medium (NYC)

Antibiotics used in NYC medium

VCAbT *Amphotericin B: Antifungal

Antibiotics to inhibit GN and GP bacteria and yeast

GC-LECT

For transportation and growth of N. gonorrhoeae

JEMBEC plates

Selective differential medium for isolation and identification of Bacteroidesfragilis

Bacteriodes bile-esculin agar (BBE)

Enrichment medium for isolation of fastidious anaerobes

Blood agar, anaerobic, CDC

Selective medium for Clostridium difficile

Cycloserine cefoxitin fructose egg yolk agar (CCFA)

For isolation of anaerobes, especially pathogenic Clostridium

Cooked meat medium

For determination of lecithinase and lipase production by clostridia and fusobacteria

Egg-yolk agar (EYA)

Selective medium for Bacteroides and Prevotella

Laked kanamycin-vancomycin blood agar (LKV)

Inhibits enteric gram-negative rods and swarming by some clostridia

Phenylethyl alcohol agar (PEA)

All-purpose medium that supports the growth of most aerobes and anaerobes. Can be used as a back up broth to detect organisms present in small numbers or anaerobes

Thioglycollate broth (THIO)

In thioglycollate broth, what acts as a reducing agent?

Thioglycolate *Aerobes grow at top, strict anaerobes at bottom, facultative anaerobes throughout.

Storage of thioglycollate broth

Store at room temperature and boil and cool prior to use

Differential medium for isolation of Corynebacterium diphtheriae

Cystine-tellurite blood agar

Enrichment medium for recovery and identification of C. diphtheriae Also promotes development of characteristic granules

Loeffler medium

Selective differential medium for C. diphtheriae

Tindale agar

Selective medium for isolation of Salmonella

Bismuth sulfite agar

Selective medium for Yersinia enterocolitica, Aeromonas, and Plesiomonas shigelloides

Cefsulodin-Irgasan-Novobiocin agar (CIN)

___ ferments manitol and appears red "bull's eye" colonies surrounded by colorless halo in CIN agar

Y. enterocolitica

Enrichment medium for recovery of Vibrio and Aeromonas from stool

Alkaline Peptone Water

Selective medium for Vibrios

TCBS

Used to speciate Haemophilus

Rabbit Blood Agar

Selective enrichment medium for isolation of Bordetella pertusis *Cough plate *Colonies resemble mercury droplets

Bordet-Gengou

Selective for B. pertusis

Regan Lowe

Enrichment medium for isolation of Legionella

Buffered charcoal yeast extract agar (BCYE)

Nonselective enrichment medium for isolation of Garnerella vaginalis

Vaginalis agar (V agar)

Semi-selective medium for G. vaginalis

Human blood Tween agar (HBT)

Selective enrichment medium used to culture mycobacteria *Colonies are rough and buff

Lowenstein-Jensen

Selective enrichment medium used to culture mycobacteria * Isoniazid-resistant strains grow better

Middlebrook 7H10 and 7H11

Enrichment medium for isolation of Leptospira from blood, CSF, and urine

Fletcher medium

Catalase-Positive organisms

Nocardia Pseudomonas Listeria Aspergillus Candida E. coli Staphylococci Serrati B. cepacia H. pylori "Cats Need PLACESS to Belch their Hairballs"

Slide test is a screening test. Detects bound coagulase (clumping factor) If negative, tube test should be performed. Detects free coagulase

Coagulase test

Agglutination of latex beads coated with fibrinogen and antibodies to protein A (protein in cell wall of S. aureus)

Slide agglutination tests for S. aureus

test used for S. saprophyticus vs other CONS

Novobiocin "NO SRES"

Detect DNase activity in aerobic bacteria

DNase test

Selective and differential for Staphylococcus species

Mannitol Salt agar (7.5% salt)

Identify group A and group B beta hemolytic streptococci

Bacitracin- SXT Susceptibility

Bacitracin and SXT results of Group A strep: Group B strep: Not Group A /Group B:

Group A strep: S - R Group B strep: R - R Not Group A /Group B: R - S "B-BRAS"

Differentiate Enterococcus (+) spp from non Enterococcus spp (-) Group A step are also + (+): pink to cherry-red color after the addition of the color developer

PYRase test

Identify group B streptococcus Group B strep produces extracellular protein. Characteristic "arrowhead" hemolytic pattern results when S. agalactiae is streaked perpendicularly to beta hemolytic S. aureus

CAMP

Identify Group B streptococcus Alternative to CAMP (+): purple color after adding ninhydrin reagent

Hippurae hydrolysis

Lancefield grouping of streptococci and enterococci (based on the antigenic nature of cell wall carbohydrates)

Slide agglutination tests

Differentiate S. pneumonia (S) from other alpha hemolytic streptococci (R)

Optochin "OVRPS"

Optochin is also known as P disk. It contains:

Ethyl hydrocuprein hydrochloride

Identification of S. pneumoniae (+) Bile salts cause lysis of some organisms (+): clearing of broth or disappearance of colony

Bile solubility

Differentiate enterococcus (+) species from non-Enterococcus species (-) Group A strep are also (+) (+): Group D Enterococcus "DE sa Pyr"

PYRase Test (PYR Test)

Distinguish Group D Streptococcus and Enterococcus from other Lancefield groups Group D strep can grow in 40% bile and hydrolyze esculin to form esculetin. Esculetin reacts with ferric citrate to form a brown-black precipitate

Bile-Esculin Agar

Differentiate group D streptococci from enterococci

6.5% Salt Broth (Salt Tolerance)

Differentiate carbohydrates in CTA tubes are oxidized into organic acids that change phenol red into a yellow color *Differentiate Neisseria species

Cystine Trypticase Agar (CTA) Sugars

Sugar in N. gonorrhoeae N. meningitidis N. lactamica N. sicca N. elongata M. catarrhalis

Glucose Gluc, Maltose Gluc, Maltose, Lac Gluc, Maltose, Sucrose (no sugar) (no sugar)

Good test to differentiate Enterobacteriacea from nonfermeters. Cytochrome oxidase, in the presence of atmospheric oxygen to form a colored compound, indophenol (+): Maroon-violet color within 30 seconds

Cytochrome oxidase

Aids in identifying members of Enterobacteriaceae (mostly +) -If organism reduced nitrates, red color develops

Nitrate reduction

Differentiate Enterobacteriaceae members All Enterobacteriaceae ferments glucose -With phenol red indicator, change from red to yellow is positive result

Carbohydrate Fermentation

Test for slow lactose fermentation Helpful in differentiating Citrobacter (+) from most Salmonella (-) -Changed to orthonitrophenol by beta-galactosidase

ONPG

Good test to differentiate Salmonella (+) from Shigella (-) -H2S reacts with iron salt in medium to form black ferrous sulfide

H2S production

Differentiate Enterobacteriaceae members -Sugar fermentation produces acid, changes color of pH indicator

Triple Sugar Iron (TSI) agar

Examples of microorganisms with K/A TSIA result

Salmonela, Shigella, P. mirabilis, Citrobacter

Examples of microorganisms with A/A TSIA result

E. coli Klebsiella Enterobacte "EKE" P. vulgaris, Citrobacter

Examples of microorganisms with K/K TSIA result

P. aeruginosa Never enterobacteriaceae

Distinguish enterobacteriaceae. Tryphtophan inthe medium is oxidized by certain bacteria which produce tryptophanase. Indole reacts with p-dimethylaminobenzaldehyde to form a red product

Indole test

Indole positive organisms

E. coli P. vulgaris K. oxytoca

Differentiate lactose fermenting enterobacteriaceae using 40% KOH

Methyl Red- Voges Proskauer

MR positive microoragnism

E. coli

VP positive organisms

Klebsiella Enterobacter Serratia Hafnia "Si VP namigay ng KESH"

Identification of lactose-dermenting enterobacteriaceae Converts into ammonia, which is then converted to ammonium hydroxide. the rise in pH causes a change in the color of the bromthymol blue indicator

Citrate

Distinguish enterobacteriaceae. Causes color change of phenol red from light orange at pH 6.8 to magenta pink at pH 8.1

Urease

Urease positive microorganisms

Proteus Cryptococcus H. pylori Ureaplasma Nocardia Klebsiella S. epidermidis S. saprophyticus "Pee CHUNKSS"

Distinguish enterobacteriaceae wherein phenylaline deaminase deaminates phenylalanine to phenyl pyruvic acid, which reacts with ferric chloride to produce green color

Phenylalanine deaminase

Microorganisms positive for PD

Proteus Providencia Morganella PD-PPMo-Green

IF an organisms has enzyme to decarboxylate amino acid Distinguish enterobacteriaceae

Decarboxylase reactions

Medium used contains a small amount of agar.

Motility

2 organisms that are the only nonmotile Enterobacteriaceae

Shigella and Klebsiella

This test is used to determine the ability of an organism to use acetamide as the sole source of carbon

Acetamide Utilization Test

Organism positive for Acetamide Utilization test

Pseudomonas aeruginosa

This test is used to determine if an organism can use acetate as the sole source of carbon

Acetate Utilization Test

Positive microorganism for acetate utilization test

E. coli

The only indole positive Enterobacteriaceae

K. oxytoca

Lactose negative Enterobacteriaceae

Shigella Edwardsiella Salmonella Citrobacter Serratia Proteus Morganella Providencia Yersinia

H2S positive Enterobacteriaceae

Proteus Edwardsiella Citrobacter Salmonella "PECS"

VP Positive Enterobacteriaceae

Klebsiella Enterobacter Serratia Hafnia "Hafnia"

PD Positive Enterobacteriaceae

Proteus Providencia Morganella Klebsiella (slow)

Urease positive Enterobacteriaceae

Pee CHUNKSS

Nonmotile at 35 deg C Enterobacteriaceae

Shigella Klebsiella Yersinia (motile at 22 deg C)

Enterobacteriaceae Lactose Fermenters

Escherichia Klebsiella Enterobacter EKE

Enterobacteriaceae that are Late Lactose Fermenters

Citrobacter Salmonella arizona Shigella sonnei Serratia Hafnia Yersinia

Enterobacteriaceae that are non-lactose fermenters

Proteus Providencia Morganella Erwinia Salmonella Shigella Edwardsiella "PPMo SESE"

There is an inverse linear relationship between the diameter of the zone of inhibited growth around the antibiotic disk and the logarithm of the minimal inhibitory concentration (MIC) of the antibiotic

Kirby-Bauer Disk Diffusion Test

Kirby-Bauer Disk Diffusion uses ___ agar

Mueller-Hinton agar

size of the MHA plate

150 x 15 mm plate

pH of the MHA

7.2 - 7.4

MHA depth

4 mm (some sources 4-6 mm)

Density of the inoculum should be adjusted to ___ standard

0.5 McFarland standard (equivalent to 1.5 x 108 CFU/mL

Composition of 0.5 McFarland standard

0.5 ml of 1.175% BaCl2 and 99.5 ml of 1% H2SO4

Only overnight colonies less than ___ hours in Kirby-Bauer Disk Diffusion test should be tested

24 hours

IN the AST, let the inoculum dry at least ___ minutes but not more than ___ minutes

5 minutes; 30 minutes

Maximum number of disks per 150 mm plate

12 disks (8 disks in outer ring, 4 disks in center)

Apply antibiotic disks, tap down firmly, and wait ___ at room temperature to allow diffusion in to the medium

3-5 minutes (not more than 15 minutes)

2 antibiotics that are best indicators of poor storage , as they are the first to deteriorate

Penicillin and methicillin

Incubate AST plate at __

35 deg C for 16 to 18 hours

Used to measure zone of inhibition with the unaided eye to the nearest mm using ___

Ruler, caliper or template

Test QC strains of E. coli, S. aureus, P. aeruginosa, E. faecalis for 20 - 30 consecutive days. If results are acceptable, frequency can reduced to ___

Weekly

3 types of beta lactamase direct test

Acidometric Iodometric Chromogenic

Chromogenic test that consists of a paper disk impregnated with a chromogenic cephalosporin. If the organism is producing beta lactamase, hydrolysis of the chromogenic cephalosporin will occur and the disk color will change from yellow to red, usually within a minute

Beta lactamase testing

Standard inoculum added to serial dilutions of antibiotics and incubated. The least amount of antibiotic (highest dilution) that prevents visible growth

Minimal inhibitory concentration (MIC)

Concentration of antibiotic that results in 99.9% decreased in CFU/mL

Minimal bactericidal concentration (MBC)

Serial dilutions of patient's peak and trough specimens inoculated with standardized amount of patient's pathogen and incubated overnight

Serum bactericidal test (Schlicter test)

Test with oxacillin disk instead of penicllin. more sensitive in detecting resistance

Screen fro penicillin susceptibility in S. pneumoniae

Oxacillin used as class representative for pencillinase-resistance penicillins. Organisms resistant to it is resistant to all.

Tests fro oxacillin- (methicillin)- resistant - S. aureus

For detection of vancomycin-resistant enterococci

Vancomycin screen

Plastic strip containing antibiotic concentration gradient placed on inoculum lawn on MH plate and incubated overnight. Useful for testing fastidious organisms such as S. pneumoniae, other strep, H. influenae and anaerobes

E test

TO detect inducible clindamycin resistance in MRSA isolates that are resistant to erythromycin and susceptible to clindamycin on initial testing.

D test

Aerobic Gram positive cocci

Micrococcus Enterococcus Streptococcus Staphylococcus "MESS"

Anaerobic gram positive cocci

Peptococcus Peptostreptococcus Sarcina "PPS"

Aerobic Gram positive bacilli

Bacillus Corynebacterium Erysipelothrix Lactobacillus Listeria Mycobacterium Nocardia "BCELLMN"

Anaerobic Gram positive bacilli

Actinomyces Clostridium Cutibacterium (Propionibacterium_ "ACC"

Aerobic gram negative cocci

Moraxella catarrhalis Neisseria

Anaerobic gram negative cocci

Veillonella

Anaerobic gram negative bacilli

Bacteriodes Fusobacterium

Pleomorphic

Mycoplasma, Ureaplasma Anaplasma Chlamydia Erhlicia Rickettsiae

Spirochetes

Borrelia Leptospira Treponema "BoLET"

Separates Staphylococcus (and Micrococcus) from Streptococcus

Catalase test

Why are colonies from blood agar not used in catalase test?

Blood has catalase and will give a false positive result -Use tryptic soy agar instead

-Gram positive spherical cells, usually arranged in grapelike clusters -Non-motile and non-spore forming -Grow on many types of media and are active metabolically -Catalase positive -Fermentative (produce acid in glucose anaerobically) -Microdase negative -Resistant to bacitracin -Suspectible to furazolidone and lysostaphin

Staphylococcus

Opportunistic pathogen. Infects prosthetic devices

S. epidermidis

2nd most common cause of UTI in young sexually active females "Honeymooner's cystitis" Nitrite negative on urine dipsticks

S. saprophyticus

Often contaminant in blood culture

S. epidermidis

Caused by ingestion of enterotoxin, a preformed toxin. Classically associated with mayonnaise in potato or egg salad

Staphylococcal Food Poisoning

microorganism that causes toxic shock syndrome using TSST-1. Most common cases are in menstruating women, especially those who are using tampons

S. aureus

Newborn disease caused by S. aureus exfoliative tocxin (Exfoliatin)

Scalded skin syndrome

Superficial cutaneous infection characterized by crusty (honey-crusted) lesions and vesicles surrounded by a red boarder. Bullous type - caused by S. aureus or S. pyogenes

Impetigo

Causes lobar pneumonia; Classically occurs following influenza ("post-infectious")

Pneumonia

Rapid onset of symptoms in patients with NO pre-existing valve disease (unlike subacute bacterial endocarditis)

Acute bacterial endocarditis

Common cause of osteomyelitis

S. aureus

Formerly called enterotoxin F

Toxic shock syndrome toxin - 1 (TSST-1)

Converts hydrogen peroxide into water and oxygen

Catalase

Spreading factor

Hyaluronidase

Fibrinolysin

Staphylokinase

-May be seen in pairs or chains -Non pigmented colony -Facultative anaerobes -Hemolytic or non-hemolytic

Streptococcus

Oxygen stable, non antigenic

Streptolysin O

Oxygen labile, antigenic

Streptolysin O

causes pharyngitis, cellulitis, impetigo ("Honey-crusted" lesions), erysipelas

Pyogenic

15 - 30% pharyngitis are due to ___

S. pyogenes

Scarlet fever, toxic shock-like syndrome, necrotixing fascitis

Toxigenic Strep

Rash following pharyngitis -skin reaction to erythrogenic toxin -"sandpaper" skin -strawberry tongue

Scarlet fever

"Flesh eating disease" -Infection of deep tissues -streptococcal pyrogenic exotoxin

Necrotizing fasciitis

Follows group A strep pharyngitis infection -anti strep antibodies cross react with tissue antigens -Type II autoimmune reaction

Rheumatic fever

Nephritic syndrome 2-3 weeks after GAS infection

Glomerulonephritis

Indicate recent S. pyogenes infection

ASO titer or anti-DNAse B antibodies

Test susceptibility for scarlet fever (+) redness or erythema of test site

Dick's test

Diagnostic test for current scarlet fever (+) blanching phenomenon (rash fades at site of injection of anti-erythrogenic toxxin)

Schultz- Charlton Reaction

-Colonizes vagina -causes pneumonia, meningitidis, sepsis, mainly in babies -most are resistant to bacitracin -Bile esculin (-) -PYR (-) -confirm by precipitin (Lancefield) FA tests or Coagglutination tests -CAMP (+) -Hippurate hydrolysis (+)

Group B Beta hemolytic streptococci

Major pathogen of the newborn -screen pregnant women 35 - 37 weeks of gestation with rectal and vaginal swabs -patients with positive cultures receive intrapartum penicillin prophylaxis

Group B Beta hemolytic streptococci

Lancet-shaped encapsulated diplococci Considered part of normal flora of the URT of preschool children Produces IgA protease

Streptococcus pneumoniae

Principal virulence factor of S. pneumoniae

Antiphagocytic capsular polysaccharide

Lobar pneumonia - associated with "rusty" sputum

S. pneumoniae

Most common caus of bacterial pneumonia in elderly as well as in patients with underlying disease

S. pneumoniae

Most common cause of bacterial meningitis in adults

S. pneumoniae

On culture, appear as alpha-hemolytic, mucoid colonies with flattened or depressed centers

S. pneumoniae

Oropharyngeal commensal; opportunistic pathogens of low virulence. -subacute bacterial endocarditis at damaged heart valves -dental caries

Viridians streptococci

Normal colonic flora

E. faecalis and E. faecium

Causes UTI (associated with catheters), biliary tract infections and subacute endocarditis (following GI/GU procedures)

Enterococcus

Important cause of nosocomial infection

Vancomycin-resistant enterococci (VRE)

Relatively resistant to cell wall agents (penicillin, ampicillin, vancomycin) -PYR (+) -Variable hemolysis

Enterococcus

Normal colonic bacteria -Rarely can cause bacteremia and subacute endocarditis -Strongly associated with colon cancer

Streptococcus bovis (Streptococcus gallolyticus)

-Oval gram-positive cocci in chains -Usually beta hemolytic on SBA -Bacitracin (S) -SXT (R) - PYR (+)

Group A streptococci (GAS)

-Oval gram positive cocci in chains -Narrow zone of diffuse beta hemolysis - SXT and Bacitracin (R) -Sodium hippurate (+) -CAMP (+)

Group B Streptococci (GBS)

-Oval, gram positive cocci in chains -Usually non hemolytic -Hydrolyzes esculin

Group D streptococci, nonenterococci

-Oval, PC in pairs and chains -Usually alpha or nonhemolytic -Hydrolyzes esculin -Grows in 6.5% NaCl broth -PYR positive

Enterococcus

-Football-shaped (lancet-shaped) GPC. Usually in pairs. May be single or in short chains. Frequently encapsulated. -Bile solubility (+) -Optochin (S)

Streptococcus pneumoniae

-GPC -Usually alpha hemolytic -Optochin (R) -Bile solubility (-)

Viridans streptococci

-GC in pairs, chains -Butterscotch or caramel odor on SBA -Usually Lancefield group F -PYR (-) -VP (+) -require 10% CO2 -Grow better anaerobically

Microaerophilic

Aerobic, gram-positive spore-forming rods; -catalase (+) Most (but not all) are motile

Bacillus

The only true pathogenic Bacillus -domesticated animals are the main host -Causes anthrax

B. anthracis

Most common type of anthrax -characteristic black painless eschar (ulcer) at the site of inoculation with surrounding edema; can lead to sepsis

Cutaneous anthrax

Antiphagocytic virulence factor of B. anthracis

Poly-d-glutamic acid capsule

EF + PA Responsible for cell and tissue edema

Edema toxin

LF + PA Cause of death in infected animals and humans

Lethal toxin

-Non motile, nonhemolytic on SBA at 24 hours -Encapsulated (from px) -Spore-forming cells stain with bamboo pole arrangement -Rounds up with media in penicillin ("Strings of pearls test") -"Medusa Head" colonies on blood agar -"Boxcar" appearance (central spores)

B. anthracis

could cause food poisoning

B. cereus

Associated with fried rice, milk and pasta Caused by ingestion of preformed emetic toxin

Emetic type of B. cereus

Associated with meat dishes and sauces, ingested spores develop into vegetative cells that secrete enterotoxins

Diarrheal type of B. cereus

Diphteria bacillus/ Kleb Loeffler's bacillus

Corynebacterium diphtheriae

An acute, contagious disease characterized by the production of a systemic toxin and a false membrane lining on the throat (pseudomembranous)

Diphteria

-Non-motile -Nitrate reduction (+) -Urease (-) -Catalase (+) -Glucose and maltose fermented -Sucrose not fermented

C. diphtheriae

Carried by beta-prophage -"Lysogenic" phage --> incorporates DNA into bacteria

Diphtheria exotoxin

C. diphtheriae has a direct smear with ___

Loffler's methylene blue (culture on Loeffler serum or Pai coagulated egg medium)

Arranged in palisades ("picket fence") or "Chinese letters" (snapping) -Metachromatic granules (Babes-Ernest granules)

Corynebacterium diphtheriae

Special culture media required for C. diphtheriae

Loeffler's or Tinsdale (Tellurite plate)

Media to enhance pleomorphisms and granule production of C. diphtheriae

1. Loeffler serum agar (+) poached egg colonies 2. Pai coagulated egg medium

Skin test for C. diphtheria susceptibility

Schick's test

In vitro virulence test for toxin production of C. diphtheriae -Soak a paper strip in diphtheria antitoxin (100U/mL) -Produce thin lines of precipitate

Elek method

The paper strip in Elek method is soaked in ____

Diphtheria antitoxin (100U/ml)

In Elek method (C. diphteriae), what is produced by the toxin and antitoxin at 45 degrees angle

Thin lines of precipitate

Nonlipophilic coryneform bacteria

C. pseudodiphtheriticum (Hoffman's bacillus)

Normal flora of the human nasopharynx

C. pseudodiphtheriticum

C. pseudodiphtheriticum characteristics

Nitrate (+), and urea hydrolysis (+)

Can cause disease similar to clinical diphtheria; carriage in domestic pets

C. ulcerans

Corynebacterium spp that rarely cause diseases in humans

C. pseudotuberculosis

Other Corynebacterium spp isolated from clinical material

C. xerosis C. striatum C. minutissimum C. amycolatum

Growth is enhanced by lipids

Lipophilic coryneform bacteria

Common cause of diphtheroid prosthestic heart valve endocarditis; multiple antibiotic resistance allows survival in hospital setting

C. jeikeium

Slowly growing species that multiply resistant to antibiotics Urease (+) UTI in immunocompromised patients Produces alkaline urine and crystal formation

C. urealyticum

Gram (+) or gram variable coccobacillus (resembling Haemophilus), or diphteroid-like rods

Listeria monocytogenes

Facultative intracellular Catalase positive Tumbling motility on hanging drop technique Hippurate hydrolysis positive Esculin (+); Salicin (+) CAMP (+) Grows from 0.5 to 45 deg C. Cold enrichment may be used

Listeria monocytogenes

CAMP (+) Hemolysis looks like shovel

L. monocytogenes

Used to detect beta hemolysis of L. monocytogenes

Sheep blood agar

L. monocytogenes produces blue-green colonies in this medium

Tryptose agar

Media that uses sheep blood for L. monocytogenes

McBride Listeria medium

What shall you use for contaminated specimens, which inhibits gram negative organisms

Phenylethylalcohol agar

Storage for Suspect cultures and tissues

Hold at 4 deg C up to 6 months Subculture weekly for 1 month, and monthly thereafter

Characteristic motility of L. monocytogenes

Umbrella-shaped pattern

Virulence test for L. monocytogenes Culture instilled in rabbit eye causes purulent conjuctivitis

Anton test

Difference of Listeria from Corynebacteria

Nonmotile, Salicin (-)

L. monocytogenes causes ___ diseases

1. Gastroenteritis 2. Meningitis 3. Infection in pregnancy 4. Granulomatosis infantiseptica

Severe in utero infection from Listeria Disseminated abscessess and or granulomas

Granulomatosis Infantiseptica

1. Slender, pleomorphic gram pos rods that form filaments; 2. May be alpha hemolytic on blood agar; 3. Decolorizes easily on gram stain thus may appear as gram negative 4. Catalase, oxidase, indole (-) p 5. H2S positive

Erysipelothrix rhusiopathiae

Disease caused by E. rhusiopathiae (aka "seal finger" and "whale finger") painful, pruritic, well circumscribed inflammatory skin lesion with a raised violaceous edge and central clearing

Erysipeloid

Characteristic pattern of E. rhusiopathiae in motility medium

Test tube brush pattern

Obligate aerobes Slender, nonspore forming, acid-fast, gram positive rods (do not gram stain well) with waxy cell wall containing mycolic acid

Mycobacterium

Stains for mycobacterium

1. acid fast 2. Auramine-rhodamine fluorescent stain (Truant)

Kinds of digestant for Mycobacterium

1. NAC (N-acetyl-L-cysteine-NaOH) - preffered 2. 2-4% NaOH

Culture media for Mycobacterium are incubated in what percent CO2

5-10%

Culture media for Mycobacterium that renders green color and is opaque

Lowenstein-Jensen (LJ)

Culture media that is good for niacin test

Lowenstein-Jensen media

Clear agar for Mycobacteria Can see colony early Good for antimicrobial susceptibility test

Middlebrook 7H10 or 7H11 agar

Both L-J and Middlebroom media contain ___ which enhances human strain of M. tuberculosis

Glycerol

Identification of mycobacteria is based on ___

pigment production, growth rate, and biochemical reactions

Best test for M. tuberculosis

Niacin test

M. tuberculosis is positive in 10 - 20 days using this test. Runyon groups II and III are positive in 5 days Hydrolysis releases oleic acid, which turns neutral red (indicator) from amber to pink

Enzymatic hydrolysis of Tween 80 (polyethylene derivative of sorbitan mono-oleate)

M. tuberculosis (+) M. bovis (-) M. kansasi (+ control)

Nitrate redution

Almost all mycobacteria are

catalase positive

Incubation of mycobacteria

69 deg C for 30 mins

After incubation of mycobacteria, M. tuberculosis and M. bovis are catalase ____

negative

The loss or reduction of catalase activity pf M. tuberculosis and M. bovis indicates resistance to

Isoniazid (INH)

What medium is used in which the growth of M. fortuitum complex is positive

MacConkey medium

Colonial morphology: Rough, wrinkled, dry, elevated, buff-colored (cauliflower-like) at 35 - 37 deg C

M. tuberculosis

How many weeks does M. tuberculosis grow

2-3 weeks

Niacin (+) yellow color Tween 80 hydrolyzed in 10 - 20 days (pink color) Nitrate (+) Catalase ata 68 deg C (-) No growth on MacConkey medium Arylsulfatase (-)

M. tuberculosis

M. tuberculosis is easily killed by

Moist heat Boiling for 10 mins Pasteurization Steam under pressure (autoclave)

Associated with skin lesions in tropical and subtropical areas (Buruli ulcers in Africa)

M. ulcerans

Requires several weeks of incubation at 32 deg C

M. ulcerans (6-9 weeks)

Niacin (-) Nitrate reduction (-) Tween 80 (-)

M. ulcerans

Photochromogens

M. marinum M. asiaticum M. simiae M. kansasii

Scotochromogens

M. scrofulaceum M. szulgai M. gordonae ("tap water scrotochromogen") M. flavescens

Non-photochromogens

M. avium-intracellulare M. malmoense M. haemophilum M. terrae-trivale M. xenopi

Rapid growers

M. phlei M. smegmatis M. fortuitum-chelonae complex

Most common non-TB mycobacterial infection

Mycobacterium avium complex

Very rare cause of pulmonary disease in non-HIV Causes disseminated disease in HIV/AIDS with low CD4 count (<50)

M. avium complex

Hansen's Bacillus

Mycobacterium leprae

obligate intracellular organism; reservoir is armadillos

M. leprae

Causes Hansen's disease (leprosy)

M. leprae

Macrophages containing acid-fast bacilli

Lepra cells

Milder form of leprosy; strong cell-mediated TH1 response contains infections; patches of hypopigmented skin with loss of sensation over affected area; (+) granuloma

Tuberculoid leprosy

Severe disease; depressed cell-mediated immunity; diffuse skin lesions with often deformed, thickened skin ; (-) granuloma

Lepromatous leprosy

Skin test for leprosy using a sterile extract from lepromatous nodules

Lepromin test

Early or Fernandez reaction

24 - 48 hours

Late or Mitsuda reaction

3 - 4 weeks

Thin, branching and beaded modified acid fast positive rods

Nocardia

Obligate Aerobe Partially acid-fast delicate mycelium Fragmenting into bacillary forms Catalase (+) and Urease (+)

Nocardia

Inhalation of Nocardia causes ___, which presents as a subacute to chronic pulmonary infection that may disseminate to other organs, usually the brain or skin, not transmitted from person to person

Nocardosis

Tissue picture: Gram (+), not stained with H&E or with special fungus stains Partially acid fast with Kinyoun stain

Nocardia

Gram neg coffee bean shaped diplococci with adjacent sides flattened; non-motile Fastidious Aerobic and capnophilic Optimal growth in a moist environment oxidase and catalase (+)

Neisseria

Oxidase and catalase (-) neisseria

N. elongata

-Never considered as normal flora -Transmitted via sexual contact; infected mother to newborn during delivery -GND, intracellular and or extracellular within polymorphonuclear neutrophils

N. gonorrhoeae

Principal virulence factor of N. gonorrhoeae

Pili

Function in adhesion of gonococci within colonies and in attachement of gonococci to host cell receptors

Opa proteins

Prophylaxis for Gonococcal ophthalmia neonatorum

1% silver nitrate solution (Crede's method), tetracyclin or erythromycin ointment

Neisseria spp that colonizes nasopharynx of healthy people

N. meningitidis

Outer membrane of N. meningitidis consists of ____ and ___ that play major roles in organism virulence

proteins and LPS

More severe pathology of N. meningitidis

Fulminant meningococcemia

Most common complication of meningococcemia

Meningitis

DIC and circulatory collapse (N. meningitidis)

Waterhouse-Friedrichsen Syndrome

Prone to recurrent Neisseria meningitidis infection (usu meningitis)

Patients with C5 - C9 deficiency

Rarely causes disease Important because it grows in selective media for gonococci and meningococci from clinical specimens; -can be cultured from the nasop

N. lactamica

Sometimes resembles N. gonorrhoeae because of its morphology and positive hydroxyprolyl aminopeptidase reaction

N. cinera

Gonococci and meningococci should be incubated in cultures in ____

5-10% CO2 and 50-70% humidity

Encourages growth of broth Haemophilus and Neisseria

Chocolate agar

enriched chocolate agar with vancomycin, colistin, nystatin (VCN) inhibitor

Thayer-Martin medium

Antibiotic that inhibits G+ organisms

Vancomycin

antibiotic that inhibits gram-neg rods

Colistin

Antibiotic that inhibits yeasts

Nystatin

Culture media for gonococci and meningococci that includes trimethoprim lactate to discourage spreading of Proteus

Modified Thayer-Martin (MTM agar)

Culture media for gonococci and meningococci that contains anisomycin instead of nystatin

Martin-Lewis Agar

ulture media for gonococci and meningococci that contains amphotericin B instead of nystatin

New York City Agar

Reagent of oxidase

1% tetramethyl-p-phenylenediamine dihydrochloride

___ in chrome loop can give a false positive reaction

Iron

4 Genera that are oxidase positive

Neisseria Aeromonas Moraxella Pseudomonas

Percent concentration of H2O2 of Superoxol test

20 - 30%

IF the culture is still positive after patient is treated with penicillin, test isolate for ___ (neisseria)

Beta lactamase

Some strains of neisseria are resistant to penicillin because they produce penicillinase are called ____

Penicillinase Producing N. gonorrhoeae (PPNG)

Test used for direct detection of N. gonorrhoeae in genitourinary specimens (preferred tests for these specimens)

Nucleic Acid Amplification Tests (NAAT)

Member of the normal microbiota in 40 - 50% of healthy school children

Moraxella catarrhalis

-Encapsulated and with pili that serve as adhesins -can be differentiated from Neisseria by its lack of carbohydrate fermentation and by its production of DNase -produces butyrate esterase, which forms the basis of rapid fluorometeric tests for identification

Moraxella catarrhalis

Most strains of this microorganism from clinically significant infections produce ___ but are still usually susceptible to cephalosporins, trimethoprim-sulfamethoxazole and beta-lactamase inhibitor combinaations

Beta-lactamase

-Gram negative rods that are either motile with peritrichous flagella or non-motile -Facultative anaerobes that grow well on artificial media -Catalase (+) -Oxidase (-) -Reduce nitrate to nitrite -Fermenters (produce acid in presence or absence of oxygen) -All are glucose fermenters with or without gas production

Enterobacteriaceae

Contains lactose permease and beta galactosidase

Lactose fermenters

Contains beta galactosidase only

Late lactose fermenters

Contains no lactose permease and beta galactosidase

Non-lactose fermenters

Somatic antigen. found in the cell wall -have lipopolysaccharide, heat stable -used for serological grouping of Salmonella and Shigella

O antigen

-Flagellar antigens -Located in the flagella -Heat labile, proteins -Used to serotype Salmonella

H antigen

-Capsular antigen -Polysaccharide, heat labile, may mask O antigen -Removed by heating -Role in preventing phagocytosis -Increasing virulence -Vi antigen is K antigen produced by S. typhi

K antigen

Colon bacillus

Escherichia coli

EMB Green metallic sheen

E. coli

IMVC: ++--

E. coli

Diseases caused by E. coli

Diarrhea UTI Neonata meningitis Gram neg sepsis "DUNG"

Organisms that causes neonatal meningitis

Group B strep E. coli L. monocytogenes

Also known as Shiga toxin - producing STEC or verotxin-producing (VTEC)

Enterohemorrhagic (EHEC)

-causes diarrhea, hemorrhagic colitis, HUS -undercooked meat, raw milk, apple cider

EHEC

Most common isolate of group and pathogen most often isolated from bloody stools

E. coli O157:H7

Culture media for EHEC

SMAC

-Traveler's diarrhea (aka Montezuma's revenge, Turista) -diarrhea in infants -transmitted by contaminated food or water

ETEC

-Bloody diarrhea, dysentery-like -usually in young children in areas of poor sanitation -causes invasiveness

EIEC

-diarrhea in infants (p=pediatric) -major pathogen in infants in developing countries -transmitted in formula and food contaminated with fecal material -adherence - attachment -watery diarrhea with mucus

EPEC

-Diarrhea in developing countries -Chronic diarrhea in HIV-infected patients -Nosocomial and community acquired -most labs can't detect

EAEC

Complicates 10% EHEC cases; usually occurs 5-7 days after diarrhea TRIAD: 1. Hemolytic anemia 2. Acute renal failure 3. Thrombocytopenia

HUS

-Intestinal flora -Have large polysaccharide capsules; nonmotile -colonies are usually mucoid in appearance -lysine decarboxylase (+) and citrate (+) -causes infection among patients with impaired host defenses (alcoholics, diabetics, with comorbidites)

Klebsiella

Common ventilator-associated pneumonia and is also associated with alcoholism (pneumococcus is still more common) and aspiration -Lobar pneumonia with a high incidence of abscesses and thick, bloody (dark red or "currant jelly") sputum

Klebsiella pneumonia

Only indole positive Klebsiella

K. oxytoca

2 most common Enterobacter spp

E. aerogenes, E. cloacae

-Motile, almost the same IMVIC reaction as Klebsiella -citrate and ornithine decarboxyolase (+) - cause opportunistic and nosocomial infections -resistant to many antibiotics -extended-spectrum beta-lactamases -resistance to most beta-lactams; penicillins, cephalosphorins, aztreonam

Enterobacter

-Flagellated and motile -Encapsulated -Produce H2S

Salmonella

In ____, Salmonella osteomyelitis is a serious and recurring problem

sickle cell patients

Typhoid enteric fever is caused mainly by ___

S. typhi

Disease and causative agent of a characteristic "rose spots" rash that may appear on the trunk of the patient in the second to third weeks. -classically presents with pulse-temperature dissociation -after recovery, 3% of px become carriers; the organism may be retained in the gallbladder and biliary passages

Enteric fever caused by S. typi or S. paratyphi

-nonmotile, fragile organism; closely relate to E. coli -causative agent of shigellosis

Shigella

Most communicable of bacterial diarrhea (<200 bacilli needed to infect a person)

Shigellosis

Produces swarming on agar Burnt chocolate odor on culture

Proteus

Most common proteus spp. Indole (+) TSI: K/A

P. mirabilis

-Indole (+) -TSI: A/A because of sucrose fermentation

P. vulgaris

Struvite kidney stones then to urinary tract obstruction

Proteus

Mainly nosocomial infections UTI Wound infections

Morganella morganii

Slow lactose fermenters

Citrobacter, Serratia marcescens

Can be found in normal GI flora Gram negative sepsis (with other GN bugs)

Citrobacter

Found in domesticated animals

Yersinia enterocolitica

Mimic Crohn's disease or appendicitis

Yersinia enterocolitica

Cause of bubonic plague "black death"

Yersinia pestis

Humans get bubonic plague from rat flea bites of ____

Xenopsylla cheopis

Chief reservoir are reptiles and freshwater fish

Edwardsiella tarda

Causes UTI and diarrhea

Providencia

Only oxidase positive enterobacteriaceae

Plesiomonas shigelloides

Pleomorphic gram negative rods in singles, pairs, short chains, or long filaments Grows on SBA and CHOC, most grow on MAC

Plesiomonas shigelloides

Most common nonfermenter

Pseudomonas aeruginosa

Gram neg, motile rods with single polar flagella

P. aeruginosa

beta hemolytic, obligate aerobe that grows readily on many types of culture media, sometimes producing a sweet or grape-like or corn taco-like odor

P. aeruginosa

Nonfluorescing bluish pigment; often produced by P. aeruginosa

Pyocyanin

Fluorescent yellow pigment

Fluorescein

Fluorescent green pigment

Pyoverdin

Dark red pigment

Pyorubin

Pyomelanin

Black pigment

Oxidizes glucose, citrate (+), oxidase (+), catalase (+)

P. aeruginosa

gives rise to blue-green pus

P. aeruginosa

Meningitis when introduced by lumbar puncture or during neurosurgical procedure

P. aeruginosa

Chronic pneumonia in cystic fibrosis patients

P. aeruginosa

An exopolysaccharide is responsible for the mucoid colonies seen in cultures from cytic fibrosis patients with chronic pneumonia

Alginate (P. aeruginosa)

"Swimmer's ear" invasive, malignant otitis externa in patients with diabetes

Mild otitis externa (P. aeruginosa)

Causes eye infection after surgery or surgical procedures

P. aeruginosa

P. aeruginosa Causes fatal sepsis in infants or debilitated persons; hemorrhagic necrosis of the skin in which the lesions are called

ecthyma gangrenosum

P. aeruginosa causes ___, associated with poorly chlorinated hot tubs and swimming pools

folliculitis

P. aeruginosa causes ___ in IV drug users

Osteomyelitis