Gram Positive Bacteria Flashcards by Jed Dano

Catalase +, Coagulase +

Staph aureus

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Catalase +, Coagulase -, Novobiocin +

Staph epidermidis

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Catalase +, Coagulase -, Novobiocin -

Staph saprophyticus

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Catalase-negative
Alpha-hemolytic
Bile-optochin-sensitive

Strep. pneumoniae

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Catalase-negative
Alpha-hemolytic
Bile-optochin-resistant

Strep. viridans

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Catalase-negative
Beta-hemolytic
Bacitracin-sensitive

Strep pyogenes

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Catalase-negative
Beta-hemolytic
Bacitracin-resistant

Strep agalactiae

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Catalase-negative

Gamma-hemolytic

Group D strep

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Box-car-shaped

Medusa head

B. anthracis

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Reheated Fried Rice

B. cereus

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Drumstick-, tennis racket-, or lollipop-like

C. tetani

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Bulging cans

C. botulinium

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Lecithinase

Double hemolysis

C. perfingens

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Pseudomembranes

C. difficile

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Curved

Chinese characters

Corynebacterium diptheria

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Curved

Tumbling Motility

Listeria monocytogenes

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Yellow “sulfur” granules

Actinomyces israelii

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Yellow pigment

Staph aureus

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Blue-green pigment (pyocyanin and pyoverdine>

Pseudomonas

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Red pigment

Serratia marcescens

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Human nose reservoir

Staphylococcus aureus

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Salt-tolerant on Mannitol salt agar (halotorelant)

Staphylococcus aureus

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Catalase-positive

Staphylococcus aureus

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prevents complement activation

Protein A

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Allows insoluble fibrin formation around organism, protecting it from phagocytosis

Coagulase

toxic to hematopoietic cells

Hemolysins

detoxifies hydrogen peroxide

Catalase

Specific for WBC

Leukocidins

secreted form of beta-lactamase; disrupts the beta-lactam portion of the penicillin molecule, thereby inactivating the antibiotic

Penicilinase

Immunomodulators of Staph Aureus (6)

``` CCHALP Catalase Coagulase Hemolysins Protein A Leukocidin Penicilinase ```

"Spreading Factor"; breaks down proteoglycans in connective tissue

Hylauronidase

dissolves fibrin clots

Fibrinolysin/ Staphylokinase

causes epidermal separation in Scalded Skin Syndrome

Exfoliatin

superantigens causing food poisoning

Enterotoxin (Heat stable)

superantigen leading to toxic shock syndrome

TSST - 1

causes marked necrosis of the skin and hemolysis

Alpha Toxin

Bullous impetigo, Hidradenitis supp, Mastitis

S. aureus

 most common cause of acute endocarditis |  native valve (tricuspid valve) in IV drug abusers

S. aureus

Empyema, Pneumatocoele, Post Viral Pneumonia

S. aureus

acute onset (4 hrs) of vomiting and diarrhea due to ingestion of preformed heat-stable enterotoxin  source: salad made with mayonnaise (potato or tuna salad)

S. aureus

separation of skin at stratum granulosum (vs TENS/Lyell disease: separation occurs at dermo-epidermal

Ritter Disease/Scalded Skin Syndrome

contain altered penicillin-binding protein (PRB) | due to resistance gene mecA

MRSA

DOC MRSA

Vancomycin

DOC VRSA

Linezolid

Penicillinase-resistant penicillins DOC

DON Dicloxacillin Oxacillin Nafcillin

Gold Color in Staph aureus colonies

Staphyloxanthin

MRSA gene

mecA

Leukocidin with propensity to form abscesses

Panton-Valentine Leukocidin | PVL

Osteomyelitis from metaphyseal area of long bone

Brodie abscess

fever, hypotension, sloughing of filiform papillaestrawberry tongue, desquamating rash and multi-organ involvement (>3)

Toxic Shock Syndrome

tampon-using menstruating women or in patients with nasal packing for epistaxis

Toxic Shock Syndrome

Humans (normal skin flora) reservoir

S. epidermidis

Polysaccharide capsule: adheres to a variety of prosthetic devices; forms a BIOFILM

S. epidermidis

Most common cause of: - prosthetic valve endocarditis - septic arthritis in prosthetic joints - ventriculoperitoneal shunt infections

S. epidermidis

Tx. S. epidermidis infection

Vancomycin | Removal of Prosthetic decive

``` Catalase positive Coagulase-negative Facultative anaerobe Nitrite-negative (unlike E. coli) Novobiocin-resistant (Novo SERS) ```

S. saprophyticus

2nd most common cause of UTI in sexually active women

S. saprophyticus

DOC in S. saprophyticus

Fluoroquinolones | TMP-SMX

``` Catalase-negative Bacitracin-sensitive (B-BRAS) Bacitracin Group B Strep Resistant Group A Strep Sensitive ```

GABHS/ Pyogenes

produces scarlet fever

Erythrogenic toxin

highly antigenic, causes AB formation; destroys RBCs and WBCs; and is the reason for the beta hemolysis *ASO Titers to document antecedent PHARYNGITIS

Streptolysin O

superantigen similar to TSST

Pyogenic exotoxin A

protease that rapidly destroys tissue → necrotizing fasciitis

Exotoxin B

perioral blisters with honey-colored crust; accumulation of neutrophils beyond the stratum corneum

Impetigo contagiosa

Complication of Impetigo contagiosa

PSAGN

superficial infection extending into dermal lymphatics

Erisepelas

deeper infection involving subcutaneous/dermal tissues; facilitated by hyaluronidase (spreading factor)

Cellulitis

most common bacterial cause of sore throat

GABHS

post-pharyngitic; due to erythrogenic toxin; seen in lysogenized strains; fever, strawberry tongue, sandpaper-like centrifugal rash, Pastia’s lines, desquamation

Scarlet Fever

Test for Susceptibility of Scarlet Fever

Dick Test

usually no site of pyogenic inflammation; blood CS negative

Staphylococcal toxic shock syndrome

recognizable site of pyogenic inflammation; blood cultures are often positive

Streptococcal toxic shock syndrome

rapidly progressive infection of deep subcutaneous tissues; facilitated by exotoxin B

Necrotizing Fascitis

GABHS DOC

Pen G

PYR Test Positive

GABHS or Group D Strep

For Lancefield Typing

Carbohydrate C

Protects from Phagocytosis and Complement activation

Protein M

Weakest Point of GABHS defense

Protein M

Fournier's Gangrene

GABHS

LIM Broth

Streptococcus agalactiae/ GBS

Hydrolyzes hippurate

Streptococcus agalactiae/ GBS

UTI in pregnant women

Streptococcus agalactiae/ GBS

NEONATAL PNEUMONIA, SEPSIS, AND MENINGITIS m/c cause

Streptococcus agalactiae/ GBS

Endometritis

Streptococcus agalactiae/ GBS

Streptococcus agalactiae/ GBS DOC:

Pen G | Pen G + Aminoglycoside - Severe Infection

Prophylaxis for GBS

IV penicillin or Ampicillin 4h prior to delivery

Camp test positive | Lancefield Group B

Streptococcus agalactiae/ GBS

Reservoir GUT and Colon

Group D streptococci

May enter bloodstream during GIT or GUT surgery

Group D streptococci

Hydrolyzes esculin in bile esculin agar (BEA)

Group D streptococci

UTIs due to indwelling urinary catheters and urinary tract instrumentation

Group D streptococci

Bilairy Tract Infection

Group D streptococci

ENDOCARDITIS in patients who underwent GIT surgery

Enterococcus faecalis

MARANTIC ENDOCARDITIS in patients with abdominal malignancy

Streptococcus bovis

DOC Group D strep

Penicillin plus gentamicin Vancomycin for penicillin-resistance Linezolid for vancomycin-resistant strains

retards phagocytosis; major virulence factor; has 84 serotypes; antigenic

Polysaccharide capsule

for colonization

IgA Protease

reacts with CRP

C substance

m/c cause of CAP in Adults

Streptococcus pneumoniae

m/c Otitis Media in Kids

Streptococcus pneumoniae

m/c cause of Bacterial Meningitidis in Adults

Streptococcus pneumoniae

DOC strep Pneumonia

Pen G | Levo or Vanco + Ceftri for Resistance

Lancet Shaped in pairs or chains

Streptococcus pneumoniae

Positive Quellung

Streptococcus pneumoniae

Polyvalent (23-type) polysaccharide vaccine Conjugated vaccine: pneumococcal polysaccharide coupled with carrier protein (diphtheria toxoid)

Streptococcus pneumoniae

Oral Flora Reservoir

Viridans

Enters bloodstream during dental procedures

Viridans

Glycocalyx enhances adhesion to damaged heart valves

Viridans

Protected from host defenses within vegetations

Viridans

DENTAL CARIES

S. mutans

most common cause of subacute and native valve endocarditis

S. sanguis

BRAIN ABSCESSES

S. intermedius

S. viridans DOC

Penicillin G +/- aminoglycoside (Gentamicin) Vancomycin for penicillin-resistance Linezolid for vancomycin-resistant strains

Woolsorter's disease

B. anthracis

Protein capsule: polymer of gamma-D-glutamic acid; antiphagocytic

B. anthracis

pXO2

Capsule

pXO1

exotoxin

the active A subunit of the exotoxin; calmodulin-dependent adenylate cyclase

Edema Factor

zinc metallo-protease that inactivates protein kinase; stimulates the macrophage to release TNF-a and IL-1B death

Lethal Factor

promotes entry of EF into phagocytic cells

Protective Antigen

M/C site of entry of Anthrax

Cutaneous

MCC of Death in Pulmonary Anthrax

Pulmonary Hemorrhage

Cutaneous Anthrax DOX

Ciprofloxacin

Inhalational/ GI Anthrax DOC

Ciprofloxacin or | Doxycycline with 1 or 2 additional antibiotics (Rifampin, Vancomycin, Penicillin, Imipenem, Clindamycin, Clarithromycin

Monoclonal Ab used for Inhalational Anthrax

Raxibacumab

M/C cause of Pulmonary Hemorrhage

- Anthrax - Leptospirosis (Weil’s syndrome) - Congenital syphilis

Medusa Head Morphology, Box Car

B. anthracis

Fried Rice

B. cereus

Cholera like toxin, ADP Ribosylation -> Inc cAMP

Heat Labile Enterotoxin

staphylococcal-like enterotoxin functions as superantigen

Heat Stable Enterotoxin

``` Rice Short IP Vomiting Short Duration Heat Stable Staphylococcal ```

Emetic

``` Meat and Veggies Longer Diarrhea Long Duration Heat Labile Clostridial ```

Diarrheal

occur after penetrating eye injuries of the eye with soil-contaminated object; complete loss of light perception within 48 h of injury

Ophthalmitis

Ophtalmitis DOC

``` Ceep the Van Gentle and Clean Ciprofloxacin Vancomgcin Gentamicin Clindamycin ```

Transmission of C. tetani

Endospore -> open wound

Only Clostridium that is non motile, (-) Flagella, (+) H Antigen Positive

C. perfringens

toxin acts on the inhibitory Renshaw cell interneurons, preventing the release of GABA and glycine (cleaves Synaptobrevin)

Tetanus Toxin/ Tetanuspasmin

Tennis Racket/ Drum Stick

Clostridium tetani

DOC for Tetanus

Metronidazole/ Penicillin, Vaccination of Tetanus Toxoid | Vaccination every 10 years

Wild raw honey

Infant botulism

Bulging Canned Goods

C. botulinum

Alkaline Vegetables

C. botulinum

Smoked Fish

C. botulinum

- inhibits release of acetylcholine from peripheral nerves  flaccid paralysis (descending pattern)

Botulinum toxin

M/C Botulinum tox serotypes in humans

A,B,E

Botox, commercial preparation of

Exotoxin A

bilateral descending flaccid paralysis Anticholinergic Bulbar sympt Eye sympt

Food Borne Botulism

when baby ingests spores found in household dust or honey; due to absence of competitive bowel microbes; constipation, flaccid paralysis

Floppy Baby Syndrome/ Indant Botulism

Triad of Botulism

Symmetric descending flaccid paralysis Bulbar signs Absence of Fever

similar to food-borne except absence of GI prodromal symptoms; due to traumatic implantation and germination of spores at the wound site

Wound botulism

Trivalent Botulinum Antitoxin

For Food borne and Wound botulism

Human botulism: immunoglobulin

For human botulism

Culture media for Clostridium botulinum

thioglycollate-enriched agar

contamination of wound with soil or feces

Micronecrosis -> C. perfringens

C. perfringens toxin

Alpha toxin lecithinase

- Due to alpha toxin - Gas produced by anaerobic metabolism - Pain, edema, and cellulitis with crepitation - Hemolysis and jaundice are common

Gas Gangrene

DOC C. perfringens

Penicillin

C perfringens culture media

Egg Yolk agar

C. difficile transmission

Feco-oral

Cytopathic effect

C. difficile

inhibit GTPase -> apoptosis and death of enterocytes -> pseudomembranes

Exotoxin A - Diarrhea | Exotoxin B - Cytotoxic to colonic epithelial cells

Antibiotics causing pseudomembarous enterocolitis

Clindamycin Ampicilin 2nd/3rd Gen Cephalosporins

DOC C. difficile

Metronidazole/ Vancomycin

can precipitate flare-ups of ulcerative colitis

C. difficile

Yellow White Plaques in Colonic mucosa

Pseudomembranous enterocolitis

Pseudomembrane in pharynx

Corynebacterium diptheriae

Encodes toxin of Corynebacterium diptheriae

B prophage

has ADP-ribosylating activity; blocks protein synthesis by inactivating EF2

Subunit A (Diptheria)

provides entry into cardiac and neural tissue

Subunit B (Diptheria)`

- Mild sore throat with fever initially - Pseudomembrane forms on pharynx (results from death of mucosal epithelial cells) - Myocarditis  A-V conduction block  dysrhythmia - Neural involvement:  peripheral nerve palsies  GBS  palatal paralysis  neuropathies

Diptheria

Club or Comma Shaped

Corynebacterium diptheriae

EF2

Diptheria

Pseudomembrane

Diptheria

GBS

Diptheria

Pseudmomembrane Myocarditis GBS

Diptheria

DOC Corynebacterium diptheriae

Penicillin/ Erythromycin

Club or comma-shaped rods arranged in V or L configuration

Corynebacterium diptheriae

Corynebacterium diptheriae culture media

Potassium tellurite | Loeffler

Babes/ Ernst Volutin

Corynebacterium diptheriae

Elek Test

Toxigenecity of Corynebacterium diptheriae

injection of diphtheria exotoxin into the skin, to determine whether a person is susceptible to infection by diphtheriae

Schick test

Ingestion of contaminated raw milk or cheese from infected cows

Listeria - can also be vaginally or transplacentally

Tumbling motility

Listeria

allows escape from the phagolysosomes of macrophages; major virulence factor

Listeriolysin O

interacts with E-cadherin on the surface of cells

Internalin

propel the bacteria through the membrane of one human cell into another

Actin Rockets

The only gram positive bacteria that produces LPS

Listeria

``` (Granulomatosis Infantiseptica) - transplacental transmission - characterized by:  late miscarriage  birth complicated by sepsis, multiorgan abscesses, and disseminated granulomas ```

EARLY-ONSET NEONATAL LISTERIOSIS

Transplacental

Early Listeriosis

- transmitted during childbirth - manifests as:  meningitis  meningoencephalitis

LATE-ONSET NEONATAL LISTERIOSIS

- second most common cause of meningitis in people > 50yo

Adult Listeriosis

- most common cause of meningitis in immunocompromised patients

Adult Listeriosis

Septicemia in Pregnant women

Adult Listeriosis

DOC Listeria

Ampicillin + Gentamicin

DOC Listeria if allergic to ampicillin

TMP-SMX | if allergic to penicillin

V- or L-shape exhibiting tumbling motility

Listeria

Facultative intracellular organism

Listeria

Cell mediated Immunity is protective

Listeria

Causes of Neonatal Meningitis

GBS E. coli Listeria

Nocardia stain

Fite Faracao

* Pulmonary infections in immunocompromised (can mimic TB but with negative PPD) * cutaneous infections after trauma in immunocompetent * can spread to CNS  brain abscesses (orange colonies)

Nocardia

DOC Nocardia

Sulfonamides

DOC Actinomyces

Penicillin

PID with IUD

Actinomyces israelii

* Oral/facial abscesses that drain through sinus tracts * Often associated with dental caries/extraction * Forms yellow “sulfur granules” * Can cause PID with IUDs

Actinomyces israelii

If isolated in blood cultures may indicate possible malignancy

Clostridium septicum

Nontraumatic myonecrosis in immunocompromised patients

Clostridium septicum

Toxic shock syndrome associated with septic abortion

Clostridium sordelli

Traumatic wound infections

Clostridium tertium