Most common cause of traveller's diarrhea is:

Ans: B (ETEC) Ref: Ananthanarayan, Paniker CJ. Textbook of Microbiology. 8th Edition. London: John Wiley & Sons: 2009. Pg 276-7Explanation:There are 5 classes of E. coli that cause diarrheal diseases:Enterotoxigenic E. coli (ETEC)Enteroinvasive E. coli (EIEC)Enterohemorrhagic E. coli (EHEC)Enteropathogenie E. coli (EPEC)Enteroaggregative E. coli (EAggEC).ETECFimbria! adhesins e.g. CFA I, CFAII, K88, K99Non invasiveProduce labile toxine (LT) and/or Stable toxin (ST) toxinWatery diarrhea in travelers (Traveller's Diarrhea).No inflammation. No fever EIECNon fimbria l adhesins, possibly outer membrane proteinInvasive, penetrate and multiply within epithelial cellsDoes not produce shiga toxinDysentery-like diarrhea (mucous, blood)Severe inflammation. FeverEPECNon fimbria] adhesin (intimin)Moderately invasive (not as invasive as Shigella or EIEC.Does not produce LT or ST; some reports of shiga-like toxinUsually infantile diarrhea; watery diarrhea similar to ETECSome inflammation, no feverEAggECProduce ST-Itke toxin (EAST) and a hemolysinPersistent diarrhea in young children without inflammation, no feverEHECModerately invasiveProduce shiga toxinPediatric diarrhea,Copious bloody discharge (hemorrhagic colitis)Intense inflammatory response, may be complicated by hemolytic uremic synromeShiga Toxin-Producing Escherichia coli (STEC)A type of enterohemorrhagic E. coli (EHEC) bacteriaHemolytic Uremic Syndrome