Lecture 35 - Vibrio - 18 Oct 2006

Clinical case A 64-year old man known to be heavy smoker for the last 38 years , presented with progressive shortness of breath, persistent productive cough, purulent sputum and fever 390C 2 days prior to admission. He was found to have a left lower lobe infiltrate on chest X-ray. Two blood cultures obtained at admission revealed the following organism

What is the causative organism? Name 2 risk factors for becoming infected with this organism? What strategies are available to prevent infections with this organism?

Vibrio

Dr. Noura AL-Sweih

Vibrio Found as natural resident of aquatic environments Most important pathogens of man are  Vibrio

cholera  Vibrio parahaemolyticus  Vibrio vulnificus

Vibrio They are short gram-negative, curved rods All are oxidase-positive Non-halophilic ie. Can grow in media without added salt eg. V.cholerae Halophilic ie. Will not grow in the absence of salt eg. V. parahaemolytics & V.vulnificus

Vibrio Growth on TCBS Media V. cholerae ferment sucrose  yellow colonies V. parahaemolyticus & V. vulnificus  not- ferment sucrose  green colonies

TCBS

Vibrio cholerae Antigenic structure O antigen (somatic antigen)  O1

V.cholerae (Causative organism of epidemic

cholera)

 non-O1

in man

V.cholerae  may cause diarrhoea

Biotypes  Classical 

Eltor

Vibrio cholerae V. cholera Cell wall antigen O1 Non-O1

biochemical tests Classical Eltor

V. cholera:O1: classical

Vibrio cholerae Clinical Presentation Sever vomiting and profuse watery diarrhea (rice water stool )  hypovolemia & shock Route of entry : gut /eating or drinking from contaminated sources

Vibrio cholerae Pathogenic mechanism  Ingestion

/ pass stomach acidity  Multiplication in small intestine  Production of Exotoxin (Enterotoxin) known as cholera toxin  Toxin consist of 2 subunits  B-subunit

= adherence  A- subunit = CAMP  fluid loss

Vibrio cholerae Treatment Oral Rehydration Therapy = ORT  Tetracycline & Co-trimoxazole Why? 

Reduce period of excretion of V.cholera in stool  Reduce environment contamination  Reduce risk of cross- infection 

Vibrio cholerae Epidemiology  Six

pandemics  V.cholera O1classical  Seventh pandemic  V.cholera O1 Eltor

Control  Safe

water supply  Proper disposal of sewage  Vaccines  A-

Parenteral [killed]  unreliable  B- Oral [Inactivated & attenuated]  better protection

Vibrio Parahaemolyticus Clinical Infections  Food

poisoning  after 2 days   Diarrhoea & abdominal pain  Most strains from seafood  Common in Japan & Singapore

Treatment  ORT

Vibrio Vulnificus Three clinical syndromes Rapid onset of Septicaemia  ⇑mortality 50% condition associated with consumption of raw shellfish Rapid progressive Cellulitis  followed contamination of wound sustained during exposure to salt water Acute diarrhoea  followed consumption of shellfish  less common & mild

Food poisoning Friends developed sever vomiting 2 hrs after having sweets in a restaurant Wife and husband developed abdominal pain and diarrhea after eating in Japanese restaurant 2 children developed sever bloody diarrhea and abdominal pain after eating in one of fast food restaurant 48hrs after eating chicken shawarma 5 of the family members developed sever diarrhea and abdominal pain A couples developed abdominal pain and diarrhea after eating in Chinese restaurant