Vibrios

Sharq Elneil College

School of Medical Laboratory Sciences

Department of Microbiology

Medical Bacteriology course

U.Mahadi Hassan Mahmoud Bsc, Msc, MIBMS Microbiology

3 Important Genera:

Vibrio

Aeromonas,

Plesiomonas

Oxidase +ve

Medically important species

Vibrio cholerae

Vibrio paraheamolyticus

Vibrio vulnificus

Vibrio species Clinical Syndromes

–Vibrio cholerae 01 (This is a

specific powerful serotype)

•Mild diarrhea to severe deadly

diarrhea

–Depends on how much toxin produced

•Vomiting can also occur

•Lose 10-25 liters a day, sometimes 1

liter/hour

•Lose 50% of body weight during

course of disease

•Death within hours (renal

failure and shock)

•Self-limiting, but have to replace

fluids and electrolytes or high

likelihood of eventual death

Vibrio cholerae non01 (less

potent serotype)

•Much milder diarrhea, not life-

threatening

Vibrio species Clinical Syndromes

Vibrio parahaemolyticus

•Seafood-associated

•Seen mostly in coastal regions

•Mild to moderate diarrhea

•Self-limiting disease, patients

recover uneventful

Vibrio vulnificus

Diarrhea associated with raw

oysters

A more threatening infection is

when patients get a wound

infection contaminated with

seawater

The wound infection progresses

rapidly and can cause death within

a day.

50% mortality rate in

Morphology

Gram negative curved rod, measuring

3–4 0.5 μm

Have a single flagellum at one end. In smears made from solid cultures, the vibrios

may appear less The use of dilute carbon fuchsin

(1 in 10) is recommended as a counterstain in the

Gram technique

when staining Vibrio species.

V. cholerae 0139, unlike V. cholerae 01, is

capsulated surrounded by a thick

capsule.

I. V. cholera O1:

–Agglutinate in Antisera Directed Against O1 Antigen.

–Produce Enterotoxin.

2. Non-Toxigenic V. cholera O1:

3. Non O1 V. cholera (NCV, NAV):

II. V. cholerae O139

Vibrio cholerae Gram-negative, curved rods

Vibrio cholerae Leifson flagella stain

Vibrio cholerae curved rods with polar flagellum (EM)

V. cholerae O1 ---------------------------------------------------

Biotye

El-tor Classic

Haemolysis (SRBC) + --

VP + --

Resistance to PB + --

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VIRULENCE FACTORS:

oEnterotoxin: CT

oAdherence: Ability to Attach to the Microvilli at the Brush Borders of the Epithelial Cells.

EPIDEMIOLOGY:

oCauses Widespread Disease.

oHuman Carriers:

oModern International

PATHOGENESIS & CLINICAL INFECTION:

Infectious Dose:

Incubation period:

Abrupt Onset of Diarrhoea &

Vomiting

Stool > Watery (Rice Water),

Odorless

Fatality Rate:

LAB. DIAGNOSIS: Isolation & Identification of the Organism. Media: TCBS Transport Media:

TREATMENT: Prompt Replacement of Fluid & Elecrolytes Tetracycline and others

PREVENTION & CONTROL: Adequate Sewage Treatment and Water Purification Systems. Vaccination:

Typical Vibrio cholera contaminated water supply

Vibrio parahaemolyticus

oHalophilic vibrio o Associated with seafood o Gastroenteritis:

oOutbreaks of Food Poisoning o Extraintestinal infections > wounds oVirulence Factors:

oHaemolysin > oheat-stable cytotoxin oHeat-labile enterotoxin oAdherence to human intestinal cells

Aeromonas species

A. hydrophila, A. sobria & A. caviae

Enterotoxins, Cytotoxins, Haemolysins, Etc… Gastroenteritis, Septicaemia, and Skin & Wound Infections

Antimicrobial Suscebtibility testing:

TMP-SMX, Tetracycline, Gentamicin Resistant to b-Lactam Antibiotics.