EXAM 02 STUDY GUIDE

enterobacterales, nonfermenters, misc

describe the general characteristics of all enterobacterales

• inhabit the gastrointestinal tract of humans

• aerobes/facultative anaerobes

• have lipid A (sepsis) & O polysaccharide in their cell wall

• oxidase NEG

• glucose fermenters

• reduce nitrates to nitrites

what are our NLF gram negative rods?

Proteus & morganella

Edwardsiella

Providencia

Shigella
Salmonella
Erwinia
Yersinia

what are our indole POS bacteria?

Morganella

Edwardsiella

Proteus vulgaris
E coli
Citrobacter
K oxytoca

what are our H2S POS bacteria?

Salmonella
Proteus
Edwardsiella
Citrobacter

what are our NONmotile bacteria?

Shigella
Klebsiella
Yersinia

what are our urea POS bacteria?

Vibrio parahaemolyticum

Proteus/morganella/providencia

Citrobacter

Yersinia

what are our citrate POS bacteria?

Proteus/providencia
Enterobacter
Citrate
Klebsiella
Salmonella

Serratia

describe MacConkey agar

selective and differential media used to isolate gram negative bacteria. contains bile salts & crystal violet that inhibits gram pos, contains lactose to differentiate lactose fermenters.

LF = pink

NLF = colorless

describe XLD agar

a selective and differential medium used to isolate and differentiate enteric pathogens, specifically Salmonella and Shigella species

shigella = red colonies

salmonella = black

nonpathogens that ferment sucrose = yellow

what are our oxidase NEG glucose fermenters?

• klebsiella

• enterobacter

• e. coli

• citrobacter

• proteus

• morganella

• providencia

• salmonella

• edwardsiella

• serratia

• shigella

• yersinia

what are our LF, VP (+) bacteria?

• klebsiella

• enterobacter

describe klebsiella pneumoniae

• 2nd common cause of UTI

• produces mucoid capsule

• hemorrhagic sputum “currant jelly”

• LDC (+), urea (+)

• antibiotic resistance caused by ESBL & carbapenemases

rhinoscleromatis: infection of nose

ozaneae: infection of nasal mucous membranes

describe klebsiella oxytoca

• indole (+)

describe klebsiella aerogenes

• UTI & wound infections & HAI

• ODC (+) LDC (+)

describe enterobacter

• LF, VP (+)

• E. cloacae = opportunistic wound & urine infections (nosocomial)

• ODC (+)

• ESKAPE

what are our ESKAPE bacteria?

Enterococcus faecium

Staphylococcus aureus

Klebsiella Pneumoniae

Acinetobacter baumanni

Pseudomonas aeruginosa

Enterobacter cloacae

describe the indole test

• Bacteria that possess enzyme tryptophanase can hydrolyze & deaminate tryptophan with the production of indole. Indole reacts with Kovac or Ehrlich reduction.

  • Positive = red

  • Negative = yellow

describe vogues-proskauer test

• bacteria produce acetoin as the end product of glucose metabolism. Acetoin is converted to diacetyl in the presence of 40% KOH & addition of alpha-naphthol catalyst for red complex.

  • Positive = red

  • Negative = no change

what are our LF, VP (-) bacteria?

• E. coli

• Citrobacter

describe E. coli & each type

• common cause of UTIs

• virulence = fimbriae, hemolysin, K1 antiphagocytic capsule

• neonatal meningitis

• enterohemorrhagic: shigatoxin (inhibits protein synthesis), O157:H7 (non sorbital fermenter on SMAC), can lead to Hemolytic Uremic Syndrome

• enterotoxigenic: traveler’s, enterotoxin (stimulates adenylate cyclase)

• interoinvasive/enteropathogenic/enteroaggresive: adhesion to epithelial cells

• LF, VP (-), Indole (+), beta-hemolytic

• antibiotic resistance caused by ESBLs (targets beta-lactam rings of 3rd gen cephalosporins)

decribe citrobacter

• LF, VP (-)

• UTI & wound infections

• black colonies on XLD

• H2S (+), urease (+)

what are our NLF enterobacterales that are PAD (+) & H2S (+)

• proteus

describe the PAD test

• detection of phenylpyruvic acid produced from deamination of phenylalanine. Green after 10% ferric chloride added.

  • Positive = green

  • Negative = yellow

describe proteus

• NLF, PAD (+), H2S (+), urease (+)

• black butt TSI

• motile by peritrichous flagella

• p. mirabilis = ODC (+)

• p. vulgaris = indole (+)

what are our NLF enterobacterales that are PAD (+), H2S (-)?

• providencia

• morganella = ODC (+)

• UTI & wound

what our our NLF enterobacterales that are PAD (-), H2S (+)?

• Salmonella

• Edwardsiella

• Serratia Marcsensens

describe Salmonella

• NLF, PAD (-), H2S (+), LDC (+)

• salmonella enterica subtype enteritidis = foodborne

  • gastroenteritis

  • black colonies XLD, poultry

• Typhoid Fever = salmonella entrica subtype Typhi or Paratyphi

  • contaminated water

  • gallbladder carrier state

  • bloodstream infection

  • small H2S band in TSI

describe edwardsiella tarda

• NLF, PAD (-), H2S (+), indole (+), LDC (+)

• fish pathogen associated with aquatic trauma

• black colonies on XLD

describe serratia marscensens

• NLF, PAD (-), H2S (+), LDC (+), ODC (+), urease (+), citrate (+)

• wound & urine

• red pigment

what are our NLF, PAD (-), H2S (-) enterobacterales?

• shigella

• yersinia

describe shigella

• nonmotile, NLD, PAD (-), H2S (-)

• bacillary dysentary

• shigatoxin

• A) s. dysentary

• B) s. flexneri

• C) s. boydii

• D) s. sonnei

• red on XLD

describe yersinia

• nonmotile, NLF, PAD (-), H2S (-), urease (+)

• motile at 25°C

• y. pestis = zoonotic plague (bubonic, pseumonic, septicemic), safety pin, fried egg

• y. enterocolitica = gastroenteritis, CIN agar plate red bullseye

• y. pseudotuberculosis = infection of lymph nodes

describe CIN agar

• cefsulodin, irgason, novabiocin for yersinia

• red bullseye

• aeromonas also red bullseye

what are our oxidase positive glucose fermenters?

• vibrio

• aeromonas

• plesiomonas shigelloides

describe vibrio spp.

• halophilic (salt loving), marine bivalves

• curved gram negative rod

• v. cholerae: rice water stools, O1 & 139 serotypes, enterotoxin, O/129 S, TCBS (+) yellow

• v. parahaemolyticum: raw shellfish, O/129 R, TCBS (-) green

• v. vulnificus: bloodstream infections after trauma & liver cirrhosis, O/129 S, TCBS (-) green

describe thiosulfate-citrate-bile salts-sucrose agar

for vibrio spp

v. cholerae yellow/POS

v. parahaemolyticum & v. vulnificus green/NEG

describe aeromonas

• oxidase (+) glucose fermenter

• medicinal leeches, gastroenetritis

• indole (+)

• red bullseye CIN

describe plesiomonas shigelloides

• oxidase (+) enterobacterale

• contaminated seafoods, gastroenteritis

what are our oxidase (+), MOTILE glucose NONfermenters

• pseudomonas aeruginosa

• pseudomonas stutzeri

• pseudomonas fluorescens/putida

• burkholderia cepacia

• burkholderia pseudomallei

• burkholderia mallei

• alcaligenes faecalis

describe pseudomonas spp.

p. aeruginosa: NLF, ARG (+), nitrate (+), 42°C (+), OXIDIZER

• infection sites with moisture (swimmer’s ear, hot tubs), cystic fibrosis pulmonary tract

• metallic sheen & mucoid

• grape odor

• pigment production

p. stutzeri: NLF, ARG (+), nitrate (+), 42°C (+), OXIDIZER

• HAI, medical equipment

• no pigment

• wrinkled yellow colonies

p. fluorecsene/putida: ARG (+), pyoverdine

• hospital water, heparin contamination

describe the O/F test

oxidative NF = Open yellow, oil green

assacharolytic NF = both green

describe burkholderia spp.

b. cepacia complex: LYS (+), ORN 30% (+), 42°C (+), oxidizer

• water & hospital disinfectants

• cystic fibrosis pts

• PCM = bright pink

• OFPBL (polymixin, bacitracin lactose) = yellow colonies

• BCSA = yellow media

b. pseudomallei: ARG (+), 42°C (+), nitrate (+)

• vietnamese time bomb

• melioidosis (agressive pulmonary disease)

b. mallei: nonmotile

• glanders, respiratory zoonosis, bioterrorism

describe alcaligenes faecalis

• motile

• asaccharoytic

• fruity odor

what are our NONmotile oxidase (+) NONfermenters?

• elizabethkingia: 42°C, indole (+)

  • no MAC growth

  • meningitis in neonates

  • yellow pigment

what are our NONmotile oxidase (-) NONfermenters?

• acinetobacter baumanii: 42°C

  • HAI & CAI

  • combat infections

  • CRAB (carbopenem resistant)

  • blue to lavendar color

  • coccobacillary

what are our NONmotile, oxidase (+) NONfermenters?

stenotrophomonas: LYS (+), 45% nitrate (+), 42°C (+), oxidizer

• HAI, cystic fibrosis

• resistant to antibiotics

• pale yellow to lavender

what bacteria have NO growth on MAC?

• campylobacter

• helicobacter

• legionella

• rickettsia

• ehrlichia chafeensis

• anaplasma phagoytophilum

• coxiella burnetii

describe campylobacter

• seagull gram stain, corkscrew/darting motility

• gastroenteritis from poultry, sheep, cattle

• microaerophilic (5% O2, 85% N2, 10% CO2)

• gullian-barre & reiter’s syndrome

• C. jejuni: hipp (+)

• C. coli

describe helicobacter pylori

• urease (+)

• acute gastritis, peptic ulcers, gastric cancer

• survives acid by breaking down urease beneath mucus layer & creating alkaline environment

• urea breath test looks for isotope tagged carbons

describe legionella

• poorly staining rods, legionellosis (severe pneumonia), pontiac (respiratory)

• survive in slime & pipes

• DFA

• requires L-cysteine, iron salts, & alpha-ketoglutarate

• BCYEalpha (buffered charcoal yeast extract)

• BCYE with PAC (polymixin B, anisomycin, cefamandole)

• BCYE with PAV (polymixin B, anisomycin, vancpmycin)

describe rickettsia

insect vectors

• rickettsia rickettsia:

  • reservoir = tick/rodent

  • vector = bit of dog tick

  • rocky mountain spotted fever with rash

• r. prowazekii

  • reservoir = humans/rodents

  • vector = body louse defecation\

  • causes typhis/epidemic or louse borne typhis

• r. typhi & felis:

  • reservoir = rodents

  • vector = dog/cat flea that defecates

  • murine/flea borne typhus with fever or rash

describe ehrlichia chafeensis

• human monocytic ehrlichiosis (HME) with morula in monocytes

  • leukopenia, thrombocytopenia, febrile illness

• reservoir = white tailed deer & dogs

• vector = lone star tick (SE midwest)

describe anaplasma phagocytophilum

• human granulocytic anaplasmosis (HGA) with morula in granulocytes

  • fever & thrombocytopenia

• reservoir = humans, canine, equine

• vector = lxodes tick

describe coxiella burnetii

• causes Q fever with granulomatous hepatits & lives in macrophages of animals

• occupational hazard, birthing, milk, inhalation of aerosols

use the flowchart for gram neg rods

use the table to differentiate glucose NONfermenters