Introduction to Microbiology Flashcards
First person to describe microorganisms
Antoni Van Leeuwenhoek
Father of Microbiology
Antoni Van Leeuwenhoek
Designed the nomenclature system for all organisms
Caroleus Linnaeus
Father of Modern Microbiology
Louis Pasteur
Manner of reproduction for Prokaryotes
Binary Fission
Enumerate all the Bacterial Morphology
Cocci, Bacilli, Spirilla, Pleomorphic
Bacilli with tapered ends are known as?
Fusiform
Example: Corynebacterium
2 most common example of a pleomorphic bacteria
Mycoplasma & Ureaplasma
Enumerate the composition of the following parts of the bacteria:
Cell Wall:
Cell Membrane:
Capsule:
Pili:
Flagella:
Enumerate the composition of the following parts of the bacteria:
Cell Wall: PEPTIDOGLYCAN
Cell Membrane: PHOSPHOLIPID BILAYER
Capsule: POLYSACCHARIDE OR POLYPEPTIDE
Pili: PILIN
Flagella: FLAGELLIN
Gram staining was developed by?
Hans Christian Gram
What are the reagents used in gram staining? Enumerate the fxn of each.
Crystal Violet: Primary Stain
Gram’s Iodine: Mordant
95% Alcohol or Acetone: Decolorizer
Safranin red: Secondary Stain
What color do red blood cell present with when stained with Gram stain
Purple
Crystal Violet is a positively charges stain attracted to negative charged particles (Such as the teichoic acid of Gram + organisms). RBC have a negatively charged outer membrane (Zeta potential)
Unique bacteria with sterols on their membrane instead of Phospholipid bilayer
Mycoplasma & Ureaplasma
Unique only to the cell wall of gram positive organisms
Teichoic Acid
Unique to the cell wall of gram negative organisms
Lipopolysaccharide (LPS)
Unique to the cell wall of Mycobacterium
Mycolic Acid
Mycolic acid allows Mycobacterium to present as Acid Fast in acid fast staining
This part of the bacterial cell is also known as the K or Vi Antigen
Capsule
A well defined capsule is known as?
Glycocalyx
This is known as the “not-well defined capsule”
Slime Layer
All encapsulated microorganisms is made up of polysaccharide gel except for?
Bacillus anthracis = Poly-D-Glutamic Acid
This part of the bacterial cell is known as the H antigen
Flagella
Functions for adherence of bacteria to host cell
Ordinary Pili
Functions for bacterial conjugation
Sex Pili
This comprises the outermost membrane of gram negative bacteria
Lipopolysaccharide
LPS contain 3 regions:
Antigenic O
Core polysaccharide
Lipid A
Also known as the murein layer
Cell wall
Alternating sugar components of the cell wall
N-acetylmuramic & N-acetylglucosamine
Used for cell wall stain
Dyar Stain
Which among the gram negative & gram positive bacteria has a thicker peptidoglycan layer?
Gram positive
The periplasmic space is unique only to (gram pos or gram neg)?
Gram negative
This pili functions for the production of infection/pathogenicity (observed with N. meningitidis)
Virulence pili
Cytoplasmic granules are composed of?
Polyphosphate
Cytoplasmic granules of Corynebacterium diphtheriae
Volutin or Babes-Ernst or Metachromatic granules
Cytoplasmic granules of Mycobacterium
Much Granules
Cytoplasmic granules of Yersinia pestis
Bipolar bodies
The cytoplasmic granules of Yersnia pestis is stained with
Wayson stain
Endospores are composed of?
Dipicolinic acid or Calcium dipicolinate
What are the two common endospore forming bacteria
Bacillus & Clostridium
True or false: Endotoxin are present in both gram pos and neg bacteria
FALSE: Only in gram neg
Protein A, Polysaccharide capsules, and M protein are examples of?
Antiphagocytic factors
Which among the endotoxin and exotoxin are heat stable and heat labile?
Exotoxin: Heat labile
Endotoxin: Heat stable
Exotoxin: destroyed rapidly by heating at >60 deg c
Endotoxin: withstand heating at >60 deg c
Which among the endotoxin and exotoxin are highly immunogenic?
Exotoxin
Exotoxin: Highly immunogenic thus it stimulates formation of high-titer toxin
Endotoxin: Weakly immunogenic
True or false: Exotoxin can be converted to antigenic toxoids
TRUE
Endotoxin: is not converted into toxoids
The phase of bacterial growth in which the bacteria is most metabolically active
Log phase (Exponential phase)
Phase of bacterial growth where the bacteria is most susceptible to antibiotics
Log phase (Exponential phase)
Bacterial growth phase in which the bacteria attempts to adapt to the new environment
Lag phase (Adjustment/Physiologic phase)
Phase of bacterial growth where waste products accumulate and nutrients are depleted
Plateu (Stationary phase)
Also known as the phase where the number of dying organisms is equal to the number of viable/living organisms
Phase of bacterial growth where the number of dying organisms are greater than the number of viable organisms
Decline (Death phase)
True or False: During the Decline/Death phase the decrease in the number of living bacteria affects the number of total bacterial count
FALSE
There is a decrease in living organisms but not i the total bacterial count. (Nandiyan pa rin yung “katawan” ng patay na bacteria)
Examples of psychrophilic clinically significant bacteria are?
Listeria monocytogenes
Yersinia enterocolitica
These are anaerobes which can grow in the presence of oxygen
Facultative aerobe
These are aerobes which can grow in the absence of oxygen
Facultative anaerobe
These type of bacteria are capable of growth in the presence of either reduced or atmospheric O2 but grow best under anaerobic conditions
Aerotolerant
Ambient air is composed of?
21% oxygen
0.03% carbon dioxide
Capnophile organisms require incubation in?
Candle Jar, CO2 incubator, or bag
It requires 5% to 10% CO2 and ~15% O2
Incubation requirement for Microerophile
Reduced O2 (5% - 10%)
Increased CO2 (8% - 10%)
This refers to both capnophiles and microaerophilic organisms
Microaerobic
Give 2 clinically significant capnophilic organisms
Haemophilus influenzae
Neisseria gonnorhoea
Give 2 clinically significant microaerophiles
Helicobacter pylori
Campylobacter jejuni
These are salt-loving organisms that grows at pH of 8.0 - 10.0
Halophilic organisms
Medically important halophilic organism
Vibrio
Example of an acidophilic organism
Lactobacillus acidophilus
Organisms that require organic substance (carbohydrate or peptone)
Heterotrophic/Organotrophic
Organisms that require inorganic substance
Autotrophic/Lithotropic
A process that kills all forms of microbial life, including bacterial endospores
Sterilization
A process that destroys pathogenic organisms, but not necessarily all micoroorganisms, endospores, or pions
Disinfection
The process of removing pathogenic organisms so items are safe to handle or dispose of
Decontamination
Incineration requires burning hazardous materials to temp of what?
870 deg to 980 deg c
This is known as the safest method to ensure that not infective materials remain in samples or containers when disposed
Incineration
A method of sterilization that uses steam under pessure
Autoclave
Autoclave setting for biologic waste (broth or solid media) also known as the displacement sterilizer
15 lbs psi at 121 deg c for 30 min
Autoclave setting for pre-vacuumed sterilizer
15 lbs psi at 132 deg c for 4 min
Autoclave setting for infectious medical waste (body fluids or blood)
15 lbs psi at 132 deg c for 30 to 60 min
Biological indicator for autoclave
Bacillus stearothermophilus
Method used to sterilize glassware, oil, petroleum, or powders
Oven
Setting for sterilization using oven (dry heat)
160 to 180 for 1.5 to 3 hrs
Biological indicator for oven sterilization
Bacillus subtilis var nigger
Method of sterilization for heat sensitive substances such as antibiotic solution, toxic chemicals, radioisotopes, vaccines, and carbohydrates
Filtration
Method of sterilization for disposables such as plastic syringes, catheters, or gloves before use
Ionizing (gamma) radiation
Most common chemical sterilant used for sterilizing heat-sensitive objects
Ethylene oxide
This chemical sterilant is an oxidizing agent used to sterilize HEPA filters in BSC, metals, and non-metal devices such as medical instruments
Vapor-phase hydrogen peroxide
Disinfection using boiling method requires (setting)
100 deg c for 15 min
Kills food pathogen without damaging the nutritional value or flavor
Pasteurization
This pasteurization technique kills milk-borne pathogens and vegetative forms
Batch method
Batch method (setting)
63 deg c for 30 min
Flash method of pasteurization (setting)
> 72 deg c at 15 sec
Method of disinfection that uses UV light and is commonly used in BSC
Non-ionizing radiation
This type of sterilization technique is composed of short wavelength and high energy gamma rays
Ionizing (gamma) radiation
This method of disinfection uses long wavelengths and low energy rays
Non-ionizing radiation
This type of chemical disinfectant is used for cold sterilization
Glutaraldehyde
Examples of Halogen disinfectants
Iodine tincture
Iodophor
Chlorine
What is the difference between tincture of iodine and iodophor
Tincture of iodine: iodine + alcohol
Iodophor: povidone iodine
One of the most effective disinfecting agents against HIV and HBV. (How many minutes of exposure?)
Chlorine
HIV = 2 min
HBV = 10 min
Disposal of this hazardous waste requires double bagging of said waste and decontamination by autoclaving or incineration
Infectious waste (agar plates, tubes, reagent bottles)
Disposal of this hazardous waste requires placing said waste into rigid carboard containers before disposal
Pipets, swabs, and other glass materials
Disposal of this hazardous wastes requires placing said waste in thick boxes lined with plastic biohazard bags and when full is incinerated or autoclaved
Broken glass
Disposal of this hazardous waste requires said waste to be placed in a sharps container and is incinerated or autoclaved when full
Sharp objects
HEPA filters removes organisms larger than __ um
0.3 um
Most clinical microbiology uses what type of BSC
Class IIa or IIb
Centrifuges must be placed inside what type of BSC to prevent emitted aerosols from dispersing widely
Class III BSC
Type of BSC with an open front, with negative pressure, ventilated to the outside
Class I BSC
This type of BSC sterilizes air that flows over the infectious material, as well as air to be exhausted
Class II BSC
Also known as the vertical laminar flow BSC
Class II BSC
This type of Class II BSC recirculate 70% of air and is self contained
Class IIA
In this type of class II BSC exhaust air is discharged outside the building. This is commonly used for radioiosotopes, toxic chemicals, or carcinogens
Class II b
This type of BSC is completely enclosed, with negative pressure. This provides maximum protection to workers
Class III BSC
Class I and Class II BSC are used for what type of BSL
BSL 2 & 3
Class III BSC is used for what type of BSL
BSL 4
Biologic agents with no known potential for infecting healthy people and are well defined and characterized belong to what biosafety level group?
BSL 1
Biologic agents acquired by ingestion or exposure to percutaneous or mucous membrane belong to what BSL
BSL 2
Biologic agents most commonly being sought in clinical specimens and are used in diagnostic, teaching, and other laboratories belong to what BSL
BSL 2
Biologic agents which are potential agents for aerosol transmission belong to what BSL
BSL 3
Biologic agents which are considered exotic agents that are considered high risk and can cause life threatening diseases belong in what BSL
BSL 4
Wrong site, wrong procedure, and wrong patient errors are termed as never events or…
Sentinel events
Interpretation of specimen results by the microbiologist belong under what step of the total testing process
Analytical step
Interpretation of report by the clinician belong to under what step of the total testing process
Post-analytical
Long term storage of aerobes or anaerobes can be done through the use of?
Lyophilization
The process that combines dehydration and freezing to prevent microorganisms from reproducing and to store them for future use
Lyophilization
Nonfastidious, aerobic organisms can be saved up to ________ on _________
1 year on trypticase soy broth
Frozen nonfastidious organisms should be thawed, reisolated, and refrozen every ________
5 years
Frozen fastidious organisms should be thawed, reisolated, and refrozen every ________
3 years
It is the process of being dessicated or thoroughly dried
Dessication
Specimens for culture must be collected during ___________ and before ________
Specimens for culture must be collected during the acute phase of infection (within 2-4 days of viral infection) and before antimicrobial, antifungal, or antiviral administration
____________ is used to neutralize antimicrobials in a sample if patient is already on antimicrobial
Thiol broth
This removes antimicrobials before culture
Antimicrobial removal device (ARD)
For anaerobe which type of specimen is preferred
Aspirates are preferred to swabs
For swab specimens what type of swabs should be used
Dacron or polyester-tipped swab on plastic shaft
Calcium alginate inactivates what virus?
Herpes simplex virus
Cotton and calcium alginate is toxic to what type of bacteria
Neisseria gonorrheae
Wooden shaft are toxic to what bacteria?
Chlamydia trachomatis
After collection specimens must be placed in a biohazard and transported to the laboratory ideally within __________
30 min, preferably within 2 hours
This transport medium consists of swabs in a test tube with transport media that can be activated by crushing an ampule
Stuart’s medium
This type of transport medium contains sodium thioglycolate and can maintain bacteria up to 72 hrs
Buffered semisolid agar
Also known as the modified stuart’s medium
Amies medium
This transport medium is used for transport of stool specimen and for enteric pathogen
Cary-blair medium
This is the most commonly used anticoagulant for microbiology specimen
Sodium polyanethol sulfonate
Concentration of sodium polyanethol sulfonate (SPS) for microbiology specimens
0.025%
Anticoagulant of choice for viral cultures
Heparin
Anticoagulant of choice for isolation of Mycobacterium spp. from blood
Heparin
This type of specimens for microbiology must not be refrigerated
Anaerobes, CSF, specimens suspected of harboring N. gonorrhoea
Are specimens fixed in formalin acceptable for processing in the microbiology lab
No (Rejected)
True/False: Specimens contaminated with barium, chemical dyes, or oily chemicals are still acceptable specimens for the microbiology lab
False
True/False: Gastric washings are acceptable specimens for anaerobic culture
False
These specimens are critical specimens and must be processed immediately in the lab
CSF, tissue specimens, blood specimens, sterile fluid
Blood specimens for culture must be collected _________ the fever spike
30 - 45 min BEFORE
Specimens suspected of harboring Brucella organisms should be incubated for?
3 weeks (21 days)
CFU count significant for UTI
100,000 or 1 x 10^5 CFU/mL
CFU count significant for UTI in S. saprophyticus
10 000 CFU/mL or 1 x 10^4 CFU/mL
Measurement for the calibrated inoculating loop used for all urine specimens
0.001 mL (1uL)
Calibrated inoculating loop used for specimens from women with suspected acute urethral syndrome and suprapubic aspirates
0.01 mL (10uL)
Most common pathogen in throat culture
Streptococcus pyogenes
Pathogen for oral thrush
Candida albicans
Pathogen for epiglotittis
Haemophilus influenzae
This type of specimen is used to detect the carrier state of staphylococcus aureus
Nasal swab
This is the specimen of choice for Bordatella pertussis isolation
Nasopharyngeal swab
This specimen is used for detection of carrier state of N. meningitidis
Nasopharyngeal swab
This assesses the quality of sputum samples
Bartlett’s classification
Revised criteria for indication of mucosal or saliva contamination
> 25 epithelial cells per LPF
All spiral organisms are reported as (Gram pos or neg)?
Gram negative
All yeasts are gram pos of neg?
Gram positive
Auramine-rhodamine method is used for?
Acid fast organisms
Mycobacterial cells appear _________ when stained using the Auramine-Rhodamine method
Bright yellow or orange against a greenish background
This type of acid fast staining method differentiates M. smegmatis & M. tuberculosis
Pappenheim method
This type of acid fast staining method differentiates M. leprae & M. tuberculosis
Baumgarten Method
Type of acid fast staining method useful for the identification of coccidian oocytes, and ideal for cryptosporidia and cyclospora
Modified acid fast stain
Oocytes appear _________ when stained using the Modified Acid Fast Stain
Magenta against a blue background
Special stain for Cell wall
Dyar stain
Special stains for Capsule
Anthony’s, Hiss’, Gin’s
Special stain for metachromatic granules
Albert, Neisser
Special stain for endospore
Dorner, Schaeffer-Fulton
Schaeffer-Fulton stain is composed of?
Malachite green and Safranin red
Stains flagella
Gray, Leifson
Stains DNA
Feulgen
Stains spirochetes
Levaditi’s, Fontana-Tribondeau
Stains Rickettsia
Gimenez
Demonstrates metachromatic granules and characteristic morphology of Corynebacterium diphtheriae from Loeffler coagulated serum medium
Methylene Blue
Example of an indirect or negative stain
India ink/Nigrosin
Used to stain specimens directly for the presence of fungi
Calcofluor white
Produces Chartreuse fluorescence when exposed to UV light
Fusobacterium nucleatum
Produces a brick-red fluorescence under UV
Prevotella porphyromonas
Produces red color under UV
Veilonella
Produces pyoverdin that fluoresces under UV light
Pseudomonas aeruginosa
Produces a green pigment
P. aeruginosa
Produces a brick red pigment
S. marsescens
Produces a blue pigment
Kluyvera spp
Produces a brown-black pigment
Prevotella melaninogenica
Produces a purple pigment
Chromobacterium violaceum
Old sock odor
S. aureus
Fruity or grape like odor
P.aeruginosa
Putrid odor
P. mirabilis
Musty basement, mousy or mouse nest odor
Haemophilus spp., Pasteurella
Mushroom odor
Pasteurella
Freshly plowed field odor
Nocardia
Horse stable odor
C. difficile
Burnt chocolate, chocolate cake odor
Proteus
Gold standard for molecular techniques in microbiology
Polymerase chain reaction
Most abundant normal flora of throat and nasopharyngeal cultures
Streptococcus viridans
Most common pathogen of throat and nasopharyngeal cultures
Streptococcus pyogenes
Preservative of choice for urine culture
Boric acid
