Gram Negative Fermentative (Enterobacteriaciaeae) Flashcards by Gilbert Villegas

General Characteristics of Enterobacteriaciaeae

Facultative Anaerobe
Catalase Positive, Oxidase Negative
Glucose Fermenters
Nitrate Reducers
Motile with Preitrichous flagella

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All enterobacteriaceae are motile except;

mnemonics: SKY

Shigella
Klebsiella
Yersinia

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All are normal flora of the Gut except;

Shigella
Salmonella
Yersinia

True Enteric Pathogens

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H antigen

Flagellar antigen

Heat labile, Protein

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O antigen

Somatic antigen

Heat stable, Lipopolysaccharide

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K antigen

Capsular antigen

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Masks O antigen

K antigen

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When somatic antigen is negative, but the capsular antigen is positive, what should you do next?

Boil for 15 minutes

Capsular antigen is heat labile that wil destroy K antigen

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K antigen of S. typhi

Vi antigen

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Most common cause of UTI

E. coli

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Virulence factor causing 75% of nenonatal meningitis cases

K1 Capsular antigen

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Infection cause by E. coli

mnemonics: DUNG

Diarrhea
UTI
Nenonatal meningitis
Gram (-) Sepsis

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Identical to shigatoxin by Shigella dysenteriae

Verotoxin I

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The most severe form manifestation of EHEC

Hemolytic Uremic Syndrome (HUS)

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Transmitted with ingestion of Hamburgers or undercooked meat

Enterohemorragic E. coli (EHEC)/STEC/VTEC

a.k.a Shiga toxin producing (STEC), Verotoxin producing (VTEC)

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Most common isolate of EHEC

E. coli O157:H7

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SMAC

Medium of isolating E. coli O157:H7

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Colonies of E. coli O157:H7 in sMAC

Colorless - Nonfermenter of Sorbitol

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Associated to Traveller’s Diarrhea

a.k.a Montezumas’s revenge or Turista

Enterotoxigenic E. coli (ETEC)

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Toxin produced by ETEC Diarrhea

Heat Labile Toxin

similar to Cholarogenic toxin

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Causes Bloody type of Diarrhea or Dysentery type of Diarrhea

EnterInvasive E. coli (EIEC)

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Infective dose of EIEC

> 10^6

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Infantile or Pediatric Diarrhea

Diarrhea of Infants

EnteroPathogenic E. coli (EPEC)

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Diarrhea in Malnourished children

EnteroAggregative E. coli (EAEC)

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EAEC adheres to **Hep2 cells** packed in a ________________ pattern.

Stacked Brick Pattern

Chronic diarrhea in HIV patients

EAEC

IMVC Reaction of E. coli

++-- with Gas

# Identification of E. coli * MAC: * EMB: * TSIA: * IMVC: * LOA: * Motility: * H2S: * Urease: * PAD:

* MAC: flat, dry colonies with sorrounding dark pink area precipitated with bile salts * EMB: Green metallic sheen * TSIA: A/A * IMVC: ++00 * LOA: ++0 * Motility: Motile * H2S: Negative * Urease: Negative * PAD: Negative

Klebsiella in MAC

Mucoid Pink colonies that form a string

Sputum associate with Klebsiella pneumoniae

Currant jelly-like sputum

Klebsiella causing **Granuloma inguinale**

K. granulomatis

Associated pneumonia with K. pnuemoniae

Ventilator associated pneumonia

Associated with **Rhinoschleroma**

K. rhinoscleromatis

Associated with **Atrophic Rhinitis** or **tissue degeneration disease in Nose**

K. ozonae

Klebsiella that is Indole Positive and Ornithine decarbocylase positive

K. ornitholytica

Member of Enterobacteriaciaeae that is Notile and Ornithine positive

Enterobacter spp.

# Identification of K. pneumoniae * MAC: * TSIA: * IMVC: * Motility: * LOA: * H2S: * PAD: * Urease:

* MAC: Mucoid colonies * TSIA: A/A * IMVC: --++ * Motility: Nonmotile * LOA: +00 * H2S: Negative * PAD: Negative * Urease: Positive

Test that differentiate K. pnuemoniae from K. oxytoca

Indole

Test that differentiate Klebsiella from Enterobacter

Motility Ornithine Decarboxylation

Yellow pigmented Coliform found in Milk infant formula

Chronobacterium sakazaki

Differentiation of E. aerogenes vs. E. cloacea

LOA Test * E. aerogenes: ++0 - Lysine decarboxlation * E. cloaceae: 0++ - Arginine decarboxylation

# Identification of Enterobacter spp. * MAC: * TSIA: * IMVC: * Motility: * LOA: * H2S: * Urease: * PAD:

* MAC: Pink colonies * TSIA: A/A with gas * IMVC: 00++ (same with Klebsiella) * Motility: **Negative** * LOA: **Ornithine Decarboxylase Positive** * H2S: Negative * Urease: Negative * PAD: Negative

# Identification of E. aerogenes * MAC: * TSIA: * IMVC: * Motility: * LOA: * H2S: * Urease: * PAD:

* MAC: Pink Colonies * TSIA: A/A * IMVC: 00++ * Motility: Motile * **LOA: ++0** * H2S: Negative * Urease: Negative * PAD: Negative

# Identification of E. cloacea * MAC: * TSIA: * IMVC: * Motility: * LOA: * H2S: * Urease: * PAD:

* MAC: Pink Colonies * TSIA: A/A * IMVC: 00++ * Motility: Motile * **LOA: 0++** * H2S: Negative * Urease: Negative * PAD: Negative

Test that differentiate K. ozoenae from K. rhinoscleromatis

Lysine Decarboxylation * Positive: K. ozaenae * Negative: K. rhinoscleromatis Malonate Utilization * Positive: K. rhinocleromatis * Negative: K. ozoenae

**Red pigment** produced by S. marcesens

Prodigosin

Causative agent of **Red Milk**

Serratia marscecens

Causes **Nursery outbreak neonatal meningitis**

C. freundii

Test that differentiate C. freundii from C. diversus (koseri)

H2S * Positive: C. freundii * Begative: C. diversus Indole * Positive: C. diversus * Negative: C. freundii

Resembles Salmonella

Citrobacter

Test that differentiate Citrobacter from Salmonella

ONPG * Positive: Citrobacter * Negative: Salmonella LDC * Positive: Salmonella * Negative: Citrobacter

Carrier of S. typhi

Mary Mallon

Appearance of Salmonella in XLD

Red with black centers

Appearance of Salmonella in HEA

Green with black centers

Serologic Test for S. typhi causing Typhoid fever

Widal Test

Mode of Transmission of Salmonella

Ingestion of undercooked poultry and raw eggs

Salmonella that ONLY INFECT HUMANS

S. typhi S. paratyphi

Causative agent of Typhoid fever

S. typhi

Causative agent of Paratyphoid fever

S. paratyphi A & B

Causative agent of Gastroenteritis

S. entritidis

Biologically inert type of bacteria

Shigella

Characterized by a **Blood type** of diarrhea | also with mucos, and pus in the stool

Bacillary dysentery/Shigellosis

Causative agent of the most severe type of bacillary dysentery

Shigella dysentery

Test that differentiate Shigella from E. coli

Acetate Utilization Test

Related to E. coli

Shigella

Test that differentiate S. sonnie from other Shigella spp.

Positive: Ornithine Decarboxylation & ONPG

Only Shigella that is Mannitol fermentation negative

S. sonnei

# Identification of Shigella * Motility: * TSIA: * IMVC: * H2S: * LOA: * PAD: * Urease:

* Motility: Nonmotile * TSIA: K/A * IMVC: **-+--** * H2S: Negative * LOA: --- * PAD: Negative * Urease: Negative

# Identification of Shigella dysenteriae * Mannitol * ODC: * ONPG:

* Mannitol Negative * ODC: Negative * ONPG: Negative

# Identification of Shigella dysenteriae * Mannitol * ODC: * ONPG:

* Mannitol: Positive * ODC: Positive * ONPG: Positive

Serratia spp. that **causes contamination of blood bag**

*Serratia liqueficans*

PAD (+)

Proteus Providencia Morganella

Test that will differentiate Proteus from Providencia & Morganella

H2S * Positive: Proteus * Negative: Providencia & Morganella

# Identification of Proteus * Culture: * Odor: * TSIA: * H2S: * Motility: * Methy Red: * Decarboxylation Test: * Urease:

* Culture: **Swarming** * Odor: Burnt **Gun powder**/**Burnt chocolate odor** * TSIA: K/A with Gas * H2S: **Positive** * Motility: Positive * Methy Red: **Positive** * Decarboxylation Test: Lysine & Arginine Negative * Urease: **Positive**

Crystal found in urine from Proteus Infection

Struvite

Differentiates P. mirabilis from P. Vulgaris

**Indole & LOA Decarboxylation test** Indole: Positive - P. vulgaris; Negative - P. mirabilis LOA: 000 - P. vulgaris; 0+0 - P. mirabilis

Only specie of Morganella

Morganella Morganii

# Identification of Morganella morganii * IMVC: * MAC: * TSIA: * PAD: * Urease: * H2S: * Citrate

* IMVC: **++--** * MAC: NLF * TSIA: K/A **with Gas** * PAD: Positive * Urease: Positive * H2S: Negative * Citrate: **Negative**

Two major species of Providencia

P. rettgeri P. stuartii

# identification of Providencia * IMVC: * TSIA: * PAD: * Urease: * H2S: * Motility:

* IMVC: **++-+** * TSIA: K/A **without Gas** * Citrate: **Positive** * PAD: Positive * Urease: Positive * H2S: Negative * **Ferments Mannose**

Differetiates P. rettgeri from P. stuartii

**Urease** Fermentation of Adonitol Fermentation of Arabinose | Urease to mainly differentiate

Infective stage to cause Shigellosis

<200 bacilli

Y. pestis transmission

Rat flea bite

Scientific name for **Rat flea**

Xenosyplla cheopis

Causative agent of **Plaque**

Yersinia pestis

Forms of Plaque

Bubonic Pneumonic Septicemic

Culture appearance of Y. pestis in Broth

Stalactite Pattern

Stain that demonstrate Y. pestis

Wayson stain

Microscopic appearance of Y. pestis demonstrated by **Wayson stain**

Safety pin appearance with Bipolar bodies

Medium for isolation of Yersinia enterocolitica

CIN medium

Colony appearance of Y. enterocolitica in CIN

Bull's eye appearance

Most common Yersinia isolated

Yersinia enterocolitica

Y. eneterocolitica is motile at ____________________ but not at _______.

Motile at 22C (RT) but not at 35C

Associated disease of Y. eneterocolitica

Appendicitis Mimic Chron's disease

Disease of Rodents

Yersinia pestis

Disease of Guine Pigs

Yersinia pseudotubercolosis

Infection caused by Yersinia psedotubercolosis

Mesenteric lymphadenitis

Malonate test is most useful in differentiating of which members

Salmonella subgroups 2, 3 (the former Arizona)

Species of Shigella is **most commonly** associated with **diarrheal disease in the United States**

S. sonnie

Enterobacter sakazakii can best be differentiated from Enterobacter cloacae by which of the following characteristics

Yellow Pigmented Sorbitol Fermentation | E. cloacae is positive sorbitol fermentation