Enteric bacteria l.jpg
This presentation is the property of its rightful owner.
Sponsored Links
1 / 21

Enteric Bacteria PowerPoint PPT Presentation


  • 412 Views
  • Uploaded on
  • Presentation posted in: General

Enterobacteriaceae Gram negative bacilli ferment glucose oxidase (-). Enteric Bacteria. Escherichia Enterobacter Klebsiella Serratia Citrobacter. Proteus (usually nonpathogenic) Shigella Salmonella. Normal Flora vs. Pathogens. COLIFORMS. NON-COLIFORMS. Lactose Fermentation?. yes.

Download Presentation

Enteric Bacteria

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


EnterobacteriaceaeGram negative bacilli

ferment glucose

oxidase (-)

Enteric Bacteria


Escherichia

Enterobacter

Klebsiella

Serratia

Citrobacter

Proteus (usually nonpathogenic)

Shigella

Salmonella

Normal Flora vs. Pathogens

COLIFORMS

NON-COLIFORMS


Lactose Fermentation?

yes

no

normal flora

pathogen

Enterobacteriaceae: Coliform or non-coliform?


Shigella dysenteriae

Salmonella typhimurium

http://www.mpg.de/news02/news0209.htm

http://www.co.boulder.co.us/health/hpe/FactSheets/salmonella.htm

Obligate Enteric Pathogens


http://www.quarks.de/milch/06.htm

Escherichia coli O157:H7

http://www.jfha.or.jp/saikin/shashin/o157.html


Eosin Methylene Blue (EMB) Agar

E. coli

http://www.cat.cc.md.us/courses/bio141/labmanua/lab3/embeacolony.html

E. aerogenes

S. Typhimurium

P. aeruginosa


Electrons from carbos(or other food source)

Electron carriers

NO3-, SO42-,CO2

O2(Aerobic respiration)

Pyruvic acid

(Anaerobic respiration)

(Fermentation)

Black, J.G (2002) Microbiology: Principles and Explorations 5th Ed. Fig. 5.21


Fermentation Pathways

Glucose(or other sugar)

Butyric acid, butanol,isopropyl alcohol,acetone & CO2

Propionic acid,acetic acid,& CO2

Pyruvic acid

Butyric-butylicfermentation

Propionic fermentation

Black, J.G (2002) Microbiology: Principles and Explorations 5th Ed. Fig. 5.11

Butanediol& CO2

Ethyl alcohol& CO2

Acetic aid,succinic acid,ethyl alcohol,

CO2 & H2

Butanediolfermentation

Lactic acid

Alcoholic fermentation

Mixed-acidfermentation

Homolactic acidfermentation


API 20 E Test Strips


Sugar Fermentation

  • Melibiose

  • Amygdalin

  • Arabinose

  • Sorbitol

  • Rhamnose

  • Sucrose

  • Glucose

  • Mannitol

  • Inositol

Must use additional reagents to GLU to see result


Catabolic Enzymes

  • Beta galactosidase

  • Arginine dehydrogenase

  • Lysine decarboxylase

  • Ornithine decarboxylase


Citrate Utilization

blue indicates citrate utilization and alkaline by-products


Sulfur Reduction

CH2

SH

CH3

cysteine desulfurase

H2S

COOH

+

CH

H2N

CH

COOH

H2N

(hydrogen sulfide)

(alanine)

(cysteine + sodium thiosulfate)

Fe++ (in medium)

FeS

(iron sulfide)

(black ppt)


H2N

NH2

urease

2 NH3

+

CO2

C

(ammonia)

O

(urea)

Nitrogen Fixing


H2O +

H2N

Tryptophan deaminase

(indole)

COOH

CH2

CH

N

(tryptophan)

N

+

NH3

(ammonia)

+

CH3

C = O

(pyruvic acid)

COOH

Tryptophan - Indole Reaction

Must add Kovac’s reagent to see result


Acetoin Reaction

Must add KOH and α-naphthol to see result


Gelatinase(s)

  • Large group of proteolytic enzymes

  • Degrade collagen

  • Metalloproteases

  • Virulence factors


API Test : Sample Prep

  • Pick ONE SINGLE colony (no agar)

  • Emulsify colony by pipetting up and down in small amount of liquid


Inoculating API Test Strips

Overlay with mineral oil:

  • ADH, LDC, ODC, H2S, & URE

  • Fill tubules & cupules:

  • CIT, VP & GEL

  • (see pg. 223 in lab manual)


Reading API Test Strips

  • Use chart on pp. 225-8 in manual to determine results

  • Record + or – results for each test

  • Add + results in oval below tests

  • Record 7-digit code and look up ID


Why did we inoculate withPseudomonas aeruginosa?


  • Login