FINAL EXAM Flashcards
- requires 15-21% oxygen for growth
- i.e., Mycobacteria
obligate aerobe
- can grow with or without oxygen
- i.e., Enterobacteriaceae
facultative anaerobe
- grow in reduced oxygen (< 5%)
- i.e., Campylobacter, Neisseria, Helicobacter
microaerophilic
cannot grow in the presence of oxygen
anaerobe
- grow in the presence of 5-10% carbon dioxide
- Haemophilus, Neisseria
capnophilic
- enriched media
- contains blood cells
- used to identify hemolysis
SBA
- enriched media
- contains lysed blood cells that release NAD
Chocolate agar
- enriched media
- selective for organisms that require cysteine for growth
- Legionella, Francisella
BCYE (Buffered Charcoal Yeast extract)
- differential media for gram-negatives
- contains lactose, bile salts, neutral red indicator, crystal violet
- lactose-fermenters appear pink
MAC (MacConkey Agar)
- selective media for gram-negative coliforms
- permit isolation of stool pathogens
- differential for lactose and sucrose fermentation
- orange (non-pathogens), green/blue (pathogens)
HE (Hektoen enteric) media
- selective media for gram-negative coliforms
- permit isolation of stool pathogens
- Citrobacter, E. coli are yellow on plate
- Shigella is colorless
- Salmonella is red with black centers
XLD (xylose-lysine-deoxycholate) agar
- antibiotic media
- chocolate agar
- vancomycin, colistin, nystatin and trimethoprim
MTM (Modified Thayer Martin)
What do antibiotics in MTM inhibit?
- Vancomycin inhibits gram-positives
- Colistin inhibits gram-negatives
- Nystatin inhibits yeasts
- Trimethoprim inhibits swarmers (Proteus)
Micrococcaceae General Characteristics
- Gram-positive cocci, catalase positive, singly, pairs or in clusters
- Colony morphology: cream-colored, buttery on BA or CNA, some produce Beta hemolysis
- aerobic or falcultative anaerobes, non motile, non spore forming, non encapsulated
- gram positive cocci
- catalase +, coagulase -
- Bacitracin S
Micrococcus luteus
- gram positive cocci
- beta hemolytic
- catalase +, coagulase +
Staphylococcus aureus
- gram positive cocci
- catalase +, coagulase -
- Novobiocin R, Bacitracin R
- UTI’s in young, sexually active women
Staphylococcus saprophyticus
S. aureus Virulence factors
- coagulase, hyaluronidase, lipase
- enterotoxins (A-E, G-I, exfoliative, cytolytic)
- Protein A
Infections/Syndromes caused by S. aureus
- gastric infections and food poisoning
- LITERALLY ANYTHING
- Toxic Shock Syndrome (tampons, DIC)
- Scalded Skin Syndrome (SSS)
- Toxic Epidermal Necrolysis (TEN)
- selective for E. coli O157:H7 (doesn’t ferment sorbitol)
- looks for sorbitol fermentation
SMAC plate
Plate that X and V strips are added to for Haemophilus differentiation
Mueller-Hinton agar
- contains lecithinase and lipase
- C. perfringens is lecithinase +
- used for anaerobes
Egg Yolk Agar (EYA)
differential media for gram positives
CNA
- selective media for Vibrios
- contains thiosulfate, citrate, bile salts and sucrose
- cholera and alginolyticus turn yellow
TCBS agar
selective media for Burkholderia cepacia
OFPBL
- shows Prevotella pigment
- B. fragilis grows on it
KVLB agar
- gram positive cocci
- catalase +, coagulase -
- Novobiocin S, Bacitracin R
Staphylococcus epidermidis
- gram positive cocci
- catalase -, beta hemolytic
- PYR +, CAMP -
- Optochin R, Bacitracin S
Group A Strep (S. pyogenes)
- gram positive cocci
- catalase -, alpha hemolytic
- Optochin S, sodium desoxycholate +
Streptococcus pneumoniae
- gram positive cocci
- alpha hemolysis
- bile esculin +, 6.5% NaCl -, PYR -
Group D Strep (S. bovis)
S. pyogenes Virulence factors
- Protein M, Protein F, DNase, hyaluronidase, Streptolysin
- capsule, toxins
Infections of Group A Strep
- Streptococcus Toxic Shock Syndrome
- skin infections, scarlet fever, necrotizing fasciatus
- Complications: acute rheumatic fever, acute glomerular nephritis
- gram positive cocci
- catalase -, beta hemolytic
- PYR -, CAMP +
- Bacitracin R, hippurate hydrolysis + (+ = purple)
Group B Strep (S. agalactiae)
Group B Strep Virulence factors
- capsule
- DNase, protease
Infections of Group B Strep
- invasive disease in newborns
- endometritis and endocarditis
S. pneumo Virulence Factors
- capsule
- IgA protease, hyaluronidase
Infections of S. pneumo
#1 pneumonia agent in adults #1 agent of adult meningitis
- gram positive cocci
- catalase -, bile esculin +
- 6.5% NaCl +, PYR +
Enterococcus
- gram negative diplococci
- oxidase +, catalase +, superoxol +
- grows on MTM
- utilizes glucose
Neisseria gonorrhoeae
- gram negative diplococci
- oxidase +, catalase +
- utilizes glucose and maltose
Neisseria meningitidis
- gram negative diplococci
- oxidase +, catalase +
- grows on MTM
- utilizes glucose, maltose and lactose
Neisseria lactamica
N. gonorrhoeae Virulence Factors
pili, capsule, IgA protease
Infections of N. gonorrhoeae
- Males: dysuria, discharge, prostatitis, urethral stricture
- Females: up to 80% asymptomatic, discharge, leads to PID
- gram negative cocci, non-motile
- oxidase +
- asaccharolytic
Moraxella catarrhalis
- gram positive bacilli
- catalase +, non-motile, bile esculin -
- Babe-Ernst granules (seen on Loeffler’s serum agar)
Corynebacterium diphtheriae
C. diphtheriae Virulence factors
- diphtheria exotoxin
- test for toxin with Elek test
Infections of C. diphtheriae
Respiratory infection spread by aerosols
- gram positive bacilli
- catalase +, CAMP + (block)
- growth at 4C, tumbling motility, umbrella motility
- bile esculin +
Listeria monocytogenes
- gram positive bacilli
- catalase -, non-motile
- TSI is H2S +
- mostly occupational exposure (animals)
Eresipelothrix rhusiopathiae
- gram positive bacilli (variable)
- resemble fungi
- weakly acid fast
Nocardia
- gram positive bacilli
- agent of anthrax
- medusa head or egg whites, non-motile
- lecithinase +, string of pearls morphology
Bacillus anthracis
Infections/Virulence of B. anthracis
- virulence: exotoxin
- cutaneous anthrax
- pulmonary anthrax
- GI anthrax
- injection anthrax
- gram positive bacilli
- catalase +
- motile (flagella)
Bacillus cereus
Enterobacteriaceae General Characteristics
- ferment glucose
- reduce nitrate to nitrites
- oxidase negative (except Plesiomonas)
- motile at body temperature (except Klebseilla, Shigella, Yersinia)
- gram negative bacilli
- lactose fermenter, beta hemolytic, A/A
- ferments glucose, lactose, trehalose, and xylose
- H2S -, DNase -, urease -, PAD -, and citrate -
- IMVC (+ + - -)
E. coli
Types of E. coli GI Infections
- Enteropathogenic: infantile diarrhea (no blood)
- Enterotoxigenic: Traveler’s diarrhea (large inoculum)
- Enteroinvasive: like Shigella (large inoculum), blood, WBCs
- Enterohemorrhagic: bloody diarrhea, no WBC’s, O157:H7, Shiga-like toxin
- Enteroadherent: DAEC and EAEC (UTI’s)
- gram negative bacilli, non-motile
- lactose fermenter, A/A
- citrate +, H2S -, PAD -, urease -, MR -
- Indole - (oxytoca is +)
- IMVC - - + +
Klebsiella
- gram negative bacilli
- lactose fermenter, A/A
- citrate +, H2S -, PAD -, urease -, MR -
- IMVC - - + +
- lysine + (except cloacae), ODC +
Enterobacter
- gram negative bacilli
- NLF, citrate +, H2S -, PAD -, urease -, MR -, A/A
- IMVC - - + +
- ONPG +, slow lactose, DNase +
Serratia
- gram negative bacilli
- swarming on lab media, NLF
- PAD +, K/A H2S +
- lactose -, urease +, indole -, ODC +, MR +
Proteus mirabilis
- gram negative bacilli
- swarming on lab media, NLF
- PAD +, A/A H2S +,
- lactose -, urease +, indole +, ODC -, MR +
Proteus vulgaris
- gram negative bacilli
- lactose fermenter
- MR +, VP -, LDC -
- citrate +
Citrobacter
- gram negative bacilli
- NLF, motile
- MR +, PAD +, H2S -, citrate -
Morganella
- gram negative bacilli
- nosocomial infections, NLF, K/A
- MR +, indole +, PAD +, H2S -, citrate +
Providencia
- gram negative bacilli
- NLF, motile, K/A H2S+
- LDC +, urea -, indole +, MR +, PAD -
Edwardsiella
- gram negative bacilli
- NLF
- K/A H2S +, indole -, VP -, PAD -, urease -, MR +, citrate + (typhi is -), lysine +
Salmonella
- gram negative bacilli
- NLF, non-motile
- K/A H2S -, ONPG +, ODC +, urease -, H2S -, LDC -, MR +
Shigella
Four Types of Shigella
- (A) S. dysenteriae: most serious
- (B) S. flexneri: 2nd most common in US
- (C) S. boydii: in developing countries
- (D) S. sonnei: most common in US
- gram negative bacilli, NLF
- K/A H2S -, non-motile at 37C
- grows at cold temps
- ODC +, MR +, PAD -
- enterocolita = target growth on CIN agar
Yersinia
Lysine decarboxylase (breakdown)
Lysine –> cadaverine + CO2
Ornithine decarboxylase (breakdown)
Ornithine –> putrescine
Arginine dihydrolase (breakdown)
arginine –> citrulline –> ornithine –> putrescine
Vibrio cholera infections/symptoms
- rice water stool
- extreme loss of electrolytes
- cholera toxin
- gram negative bacilli, curved rods
- catalase +, oxidase +, reduce nitrate
- Vibriostat (0/129) S, String test +
- yellow on TCBS, grows in 0% NaCl
Vibrio cholera
- gram negative bacilli, curved rods, oxidase +
- summer diarrhea in Japan
- associated with seafood
- some are urease +
- green on TCBS
Vibrio parahaemolyticus
- gram negative bacilli, curved rods, oxidase +
- associated with raw or undercooked seafood (oysters)
- lactose + vibrio
- green on TCBS
Vibrio vulnificus
- gram negative bacilli, curved rods, oxidase +
- mimics cholera, yellow on TCBS
Vibrio alginolyticus
- gram negative rods
- oxidase +, glucose fermenting, beta hemolytic
- straight gram-negative rods, indole +
- mesophilic and psychophilic groups
- infection associated with contaminated water
- string test -, Vibriostat disk R
- growth in 0% NaCl, inositol -
Aeromonas
- gram-negative rods
- similar to Shigella, but lower virulence
- oxidase +, Vibriostat S, growth in 0% NaCl
- NLF, motile, IBB agar, ODC +, LDC +, ADH +
Plesiomonas
- gram negative rod
- microaerophilic (5% O2)
- non-spore forming rods (seagull-wing shape)
- oxidase +, catalase +
- darting motility
- # 1 cause of diarrhea world-wide
- Campy BAP, Skirrow media
Campylobacter jejuni
- gram negative rod
- urease +
- causes ulcers, leads to gastric carcinoma
Helicobacter pylori
- gram negative bacilli
- blue/green hue on MAC , grape-like odor
- oxidase +, catalase +, glucose oxidizer
- motile, capsule, DNase, protease, Exotoxin A
- growth at 42C, ADH +, citrate +, K/K
Psuedomonas aeruginosa
Psuedomonas dyes
pyocyanin (green hue) and pyoverdin (fluorescence)
Infections/syndromes of Psuedomonas
- nosocomial infections
- pneumonia in CF patients
- Hot tub syndrome
- gram negative coccobacilli
- oxidase -, catalase -, non-motile, NLF
- purple on MAC, K/K
Acinetobacter baumanii
- gram negative bacilli, rough colonies
- lavender/green hue on MAC, NLF, ammonia odor
- oxidase -, catalase +, non-oxidizer of glucose
- DNase +, Esculin +, LDC +, Gelatin +, K/K
Stenotrophomonas maltophila
- gram negative bacilli, motile
- slow oxidase +, glucose oxidizer
- ONPG +, LDC +, K/K
- OFPBL, BCSA selective agars
Burkholderia cepacia
- gram negative long/thin bacilli, non-motile
- hospital contaminants
- DNase +, oxidase +, Gelatin +, indole +
- Doesn’t grow on MAC
- meningitis and septicemia in newborns
Elizabethkingia meningoseptica
- gram negative bacilli
- smooth, brown/tan colonies on SBA, grows on Mac
- motile (polar flagella), oxidase +, H2S + on TSI
Shewanella
- gram negative bacilli
- capsule, sattelitism on BAP with S. aureus, IgA protease
- Growth on chocolate
- oxidase +, catalase +, reduce nitrate, porphyrin -
H. influenzae
Special growth requirements of Haemophilus
- X & V factor: H. influenzae, H. aegyptius, H. hemolyticus (Quad I, IV)
- V factor: H. parainfluenzae (Quad I, III, IV)
- X factor: H. ducreyi
- Mueller-Hinton agar with X and V strips
H. influenzae infections
Hib is the #1 cause of meningitis is unvaccinated children
- gram negative bacilli
- fastidious, requires X factor, no growth on MAC
- pits agar, K/K, oxidase +, catalase -
- bleach-like odor
Eikenella
- gram negative bacilli, non-motile
- oxidase +, catalase -, A/A
- growth on MTM
- affects bones/joints of kids
Kingella
- gram negative coccobacilli, STI
- painful chancroid, buboes
- school of fish morphology
Haemophilus ducreyi
HACEK (organsims)
- Haemophilus (Aggregatibacter aphrophilus)
- Actinobacillus/Aggregatibacter actinomycetemcomitans
- Cardiobacterium hominis
- Eikenella corrodens
- Kingella species
HACEK (characteristics)
- Don’t grow on MAC, slow growers
- usually bite wounds (mouth flora)
- cause endocarditis
- gram negative bacilli, non-motile
- fastidious, no growth on MAC
- bipolar staining, zoonotic infections
- catalase +, oxidase +
Pasteurella multocida
- gram negative bacilli
- oxidase +, catalase +, H2S +
- urease +
- undulant fever, zoonotic infections
- specimen: bone marrow*, test with growth in dyes
Brucella
- gram negative bacilli
- requires cysteine for growth (BCYE agar)
- no growth on MAC, SBA
- zoonotic infections, rabbit fever, tularemia
Francisella tularensis
- gram negative bacilli (weakly staining)
- require cysteine for growth (BCYE agar)
- inhalation transmission, associated with AC units
- invades and survives in macrophages
- Pontiac fever
Legionella pneumophilia
Bordetella virulence factor
pertussis toxin
- gram negative bacilli
- smooth, silver pinpoint colonies (like mercury droplets)
- whooping cough
- specimen collected on Dacron swab
- use Bordet-Gengou agar
Bordetella pertussis
- can survive some oxygen exposure, but can’t perform metabolic processes unless in an anaerobic environment
- i.e., Bacteroides
Aerotolerant anaerobe
- requires strict anaerobic environment and are killed almost immediately in the presence of oxygen
- i.e., Clostridium
Obligate anaerobe
Exogeneous anaerobes
- exist outside of the body
- infection develops at site of entry
- i.e., Clostridium, Fusobacterium
Endogeneous anaerobes
- exist inside the body
- source of infection in/throughout body
- usually polymicrobial infections
- i.e., Bacteroides, Peptostreptococcus, Actinomyces
Skin anaerobes
Propionibacterium, Peptostreptococcus
Respiratory anaerobes
Prevotella, Porphyromonas, Fusobacterium
GI anaerobes
Bacteroides, Clostridium
Genitourinary tract anaerobes
Fusobacterium, Prevotella, Bacteroides, Lactobacillus
- gram positive bacilli, anaerobic
- spore forming, boxcar-shaped
- double zone of beta hemolysis
- lecithinase +, catalase -
- causes gas gangrene (alpha toxin)
Clostridium perfringens
- gram positive bacilli, anaerobic
- spore forming, heavily swarming
- terminal spores
Clostridium tetani
- gram positive bacilli, anaerobic
- spore forming, heavily swarming
- subterminal spores
Clostridium septicum
Clostridium botulinum infection
- causes botulism
- botulism toxins
- due to ingestion of toxin, ingestion of spores in infants
- antibiotic-associated diarrhea
- causes pseudomembranous colitis (blood, necrosis)
- nosocomial infection, CCFA agar
- fluoresces chartreuse
Clostridium difficile
- gram positive bacilli, anaerobic
- normal skin flora
- causes granulomatous disease (“sulfur granules”)
- molar tooth colonies, infected IUD’s, lumpy jaw
Actinomyces
- gram negative bacilli, anaerobic
- # 1 flora in colon
- grows on KVLB and BBE
- bile tolerant
- pilonidal cysts
Bacteroides fragilis
- gram negative bacilli, anaerobic
- # 1 gingiva flora
- brick-red fluorescence on KVLB (then turn black)
Prevotella melaninogenica
- gram negative bacilli, anaerobic
- slow grower
- brick-red fluorescence on KVLB (then turn black)
Porphyromonas
- gram negative bacilli, anaerobic
- long, thin rods with pointed ends
- fluoresces chartreuse
- nonhemolytic, indole +, lipase -
Fusobacterium nucleatum
- gram negative bacilli, anaerobic
- pleomorphic with rounded ends
- fluoresces chartreuse
- beta hemolytic, indole +, lipase +
Fusobacterium necrophorum
- gram positive cocci, anaerobic
- common contaminant, skin flora
- catalase -, indole -, urease -, nitrate -, SPS S
Peptostreptococcus anaerobius
- gram positive cocci, anaerobic
- common contaminant, skin flora
- catalase -, indole -, urease -, nitrate -, SPS R
Peptostreptococcus asaccharolyticus
Anaerobic specimen collection
- aspirates collected and transported on PRAS media
- use methanol as fixative for gram staining instead of heat
Vancomycin disk susceptibility
- S: Porphyromonas, Clostridium
- R: Bacteroides, Prevotella, Fusobacterium
Kanamycin disk susceptibility
- S: Bacteroides, Fusobacterium
- R: B. fragilis, Prevotella, Porphyromonas