W2 - Clinical Bacteriology (Family Enterobacteriaceae)

Gram negative

Enterobacteriaceae:

Gram stain result

Coccobacilli

Enterobacteriaceae:

Morphology

Facultative anaerobe

Enterobacteriaceae:

Oxygen requirement

True

T or F: Enterobacteriaceae are non-spore formers

a.) Shigella
b.) Klebsiella
c.) Yersinia pestis (Non-motile at any temperature)

Which Enterobacteriaceae are non motile?

Room temperature

What temperature are the Yersinia spp. motile?

37°C

Yersinia spp. are non motile at \________ except Yersinia pestis

Pili, fimbriae

Enterobacteriaceae:

Some are with \_____ or \______

Mc Conkey agar

Enterobacteriaceae:

Grows well on \_______

Glucose, Shigella

All Enterobacteriaceae ferments \______ and often with gas production (aerogenic) except \_______

S. dysenteriae type 1

All Enterobacteriaceae are catalase positive except \_______

Plesiomonas

All Enterobacteriaceae are cytochrome oxidase negative except for \_________

Family Vibrionaceae

Originally Plesiomonas is not a part of the Family Enterobacteriaceae, it is part of the \_________

a.) Primary Intestinal Pathogens
b.) Opportunistic pathogens

Two types of Enterobacteriaceae based on clinical infection produced

a.) Salmonella
b.) Shigella
c.) Yersinia enterocolitica

Primary Intestinal Pathogens (pathogenic)

Opportunistic pathogens

GIT flora that can produce infections outside the GIT

a.) Common Pili
b.) Plasmid
c.) Antigens

Virulence factors of Enterobacteriaceae

Common pili

Enterobacteriaceae virulence factor:

Adherence or attachment to host cells because Family Enterobacteriaceae can attach, invade, and colonize
tissues.

Plasmid

Enterobacteriaceae virulence factor:

A small DNA molecule that confers resistance to antibiotics

Antigens

Enterobacteriaceae virulence factor:

It is used to identify other groups

a.) O antigen (Somatic/Cell wall)
b.) K antigen (Envelope/Capsular)
c.) H antigen (Flagellar)

Three antigenic determinants useful in the characterization of E. coli, Klebsiella, Shigella and Salmonella.

O antigen

Majority of Enterobacteriaceae have this antigen because most have cell walls.

164

How may types of O antigen is associated with E. coli?

E. coli Serotype 0111

E. coli serotype responsible for Neonatal diarrhea

E. coli Serotype 0157

E. coli serotype responsible for verotoxin production

K antigen

An antigen consisting of capsular polysaccharide that is heat labile

a.) Klebsiella
b.) E. coli
c.) Salmonella

What Enterobacteriacea have K antigens?

Vi antigen

The K antigen specifically for S. typhi

H antigen

Antigen that is protein in nature found among motile enterics and is heat labile

Class of Mollicutes (Mycoplasma and Ureaplasma)

What genera of bacteria are considered cell wall less?

Stool

What is the most common specimen for culturing enterobacteriaceae?

a.) Inoculation
b.) Cytochrome Oxidase Test
c.) Biochemical Test

Steps in Enterobacteriacea identification

Cytochrome oxidase Test

Screening test for Enterobacteriacea

Quantitative/semi-quantitation technique

Inoculation is done in 4 quadrants which is called the \_________

Neisseria

Thayer-Martin, Martin Lewis, New York City and GC Medium are culture media used to isolate?

Mycobacterium

Lowenstein-Jensen, Petragrani, and Middle Brooke are culture media used to isolate?

Cetrimide Agar

Isolation media used to isolate Pseudomonas aeruginosa

Bismuth Sulfite Agar (BSA)

Selective media for Enterobacteriacea

a.) Bismuth green
b.) Bismuth sulfite

Inhibitor for BSA

Glucose

Fermentable Carbohydrate of BSA

No indicator

Indicator for BSA

Black

BSA:

Salmonella Result

Salmonella Shigella Agar (SSA)

Moderately Selective and Differential media for Enterobacteriaceae

Bile salts

Inhibitor of SSA

Lactose

Fermentable carbohydrate of SSA

Colorless w/ black center

SSA:

Salmonella result

Colorless w/o black center

SSA:

Shigella result

Red

SSA:

Fermenter Result

Neutral Red

Indicator for SSA

Bile salts

Inhibitor for Hektoen Enteric Agar

Bromothymol Blue

Indicator for Hektoen Enteric Agar

a.) Salicin
b.) Lactose
c.) Sucrose

Fermentable carbohydrate for Hektoen Enteric Agar

Yellow with or without black

Hektoen Enteric Agar:

Fermenter result

Green or colorless with or without black

Hektoen Enteric Agar:

Non-fermenter result

Phenol Red

Inhibitor for Xylose Lysine Deoxycholate (XLD)

a.) Xylose
b.) Lactose
c.) Sucrose

Fermentable carbohydrate for Xylose Lysine Deoxycholate (XLD)

Yellow

Xylose Lysine Deoxycholate (XLD):

Fermenter result

Red or colorless

Xylose Lysine Deoxycholate (XLD)

Non fermenter result

a.) Eosin Y
b.) Methylene Blue

Inhibitor for EMB

a.) Eosin Y
b.) Methylene Blye

Indicator for EMB

Pink to purple

EMB and MAC:

Fermenter result

Colorless

EMB and MAC:

Non fermenter result

Neutral Red

Indicator for MAC

Lactose

Fermentable carbohydrate for MAC

a.) Crystal violet
b.) Bile salts

Inhibitor for MAC

Lactose

Fermentable carbohydrate for EMB and MAC

Klebsiella pneumoniae

It develops pink-purple mucoid colonies in EMB

E. coli

It develops pink to purple colonies with greenish metallic sheen

Enterobacter

It develops pink-purple colonies with dark center giving it a fish-eye appearance in EMB

Enrichment media

It used to enhance bacterial growth and increase bacterial yield

Selenite broth

The enrichment broth for Salmonella and Shigella

Tetrathionate broth

The enrichment broth for Salmonella

Cefsulodin Irgasan Novobiocin (CIN)

The selective media for Yersinia enterocolitica which contains mannitol and neutral red

Brilliant Green Agar (BGA)

Selective media for other Salmonella except S. typhi

Brilliant Green

Inhibitor for Brilliant Green Agar (BGA)

Phenol Red

pH indicator for Brilliant Green Agar (BGA)

Salmonella

These colonies growing on BGA may appear like snow-flakes

Red

If both red and colorless are among the choices for XLD, we choose \______

To detect acid production

What is the purpose of Fermentation tests

Triple sugar Iron (TSI)

What media is used for carbohydrate fermentation test?

Kligler's Iron Agar (KIA)

Substitute media for TSI

Sucrose

Kligler's Iron Agar (KIA) has same composition as TSI except for \______

a.) Lactose
b.) Sucrose
c.) Glucose

Fermentable carbohydrate for TSI

10:10:1

Ratio of carbohydrate for TSI (Lactose/Sucrose/Glucose)

Phenol red

pH indicator for TSI

a.) Ferrous sulfate
b.) Sodium thiosulfate

H2S indicator for TSI

Yellow, A

TSI:

In an acid pH, media will turn ____ reported as _

Red, K

TSI:

In an alkaline pH, media will remain \_____ report as \_____

Blackening of media

TSI:

H2S production is indicated by \______

a.) Splitting of media
b.) Pulling away of media
c.) Cracks on media

TSI:

Indication for Gas Production

S. typhi

It produces a a curved-wedge appearance on TSI due to a limited production of H2S

K/K

TSI:

No sugar fermented result

K/A

TSI:

Only glucose was fermented

A/A

TSI:

2-3 Sugars were fermented, with glucose always positive

a.) Enterobacter
b.) Escherichia
c.) Klebsiella

Which Enterobacteriaceae are lactose fermenters?

a.) Citrobacter
b.) Serratia
c.) S. arizonae
d.) S. sonnei
e.) Y. enterocolitica

Which Enterobacteriacea are late/slow lactose fermenters?

a.) PPM
b.) Edwardsiela
c.) All Salmonella except S. Arizonae
d.) All Shigella except S. sonnei
e.) All Yersinia except Y. enterocolitica
f.) Erwinia - plant pathogen

Which Enterobacteriacea are non-lactose fermenters?

Beta-galactosidase & lactose permease

What enzymes used for Rapid Lactose Fermenters?

Beta-galactosidase

What enzymes used for Late Lactose Fermenters?

K/K H2S (-)

TSI Reactions for Pseudomonas and Burkholderia