A cook prepares sand witches for 10 people going for picnic. Eight out of them develop servere gastroenteritis within 4-6 hrs of consumption of the sand witches. It is likely that on investigations the cook is found to be the earner of:

Ans. is 'd' i.e. staphylococcus aureus Gastroenteritis presenting within 4-6 hrs. of consumption of sandwiches confirms the diagnosis of staphylococcal food poisoning.The only other cause of Food poisoning presenting within 4-6 hrs is Bacillus cereus but it is not given in the option.* The following table will help to tackle any further question on this topic.OrganismIncubation period (hrs)VomitingDiarrheaFeverMicrobiologyPathogenesisStaphylococcus1 -8, rarely up to 18+++++-Staphylococci grow in meats and in dairy and bakery products and produce enterotoxin.Enterotoxin acts on receptors in gut that transmit impulses to medullary centers.Bacillus cereus cereus1-8, rarely up to 18++++-Reheated fried rice causes vomiting or diarrheaEnterotoxins formed in food or in gut from growth of BClostridium perfringens8-16+/-+++-Clostridia grow in rewarmed meat dishes and produce an enterotoxinEnterotoxin produced in food and in gut causes hypersecretion in small intestine. *Clostridium botulinum24-96+/-Rare-Clostridia grow in anaerobic foods and produce toxinToxin absorbed from gut blocks acetylcholine at neuromuscular junctionClostridium difficile?-++++Associated with antimicrobial drugs, eg, clindamycinEnterotoxin causes epithelial necrosis in colon; pseudomembranous colitis.Escherichia coli (some strains)24-72++-Organisms grow in gut and produce toxin. May also invade superficial epithelium.Enterotoxin causes hypersecretion in small intestineVibrio parahaemolyticus6-96+++Organism grow in seafood and in gut and produce toxin or invadeHypersecretion in small intestine; stools may be bloodyVibrio cholerae (mild case)24-72+/-+++-Organisms grow in gut and produce toxinEnterotoxin causes hypersecretion in small intestine. Infective dose: 107-109 organismsCampylobacter jejuni2-10 days-++++Organisms grow in jejunum and ileumInvasion and enterotoxin production uncertainShigella species (mild cases)24-72+/-++Organisms grow in superficial gut epithelium and gut lumen and produce toxinOrganism invade epithelial cells; blood, mucus, and PMNs in stools. Infective dose: 102 - 103 organismsSalmonella species 8-48+/-++Organism grow in gut. Do not produce toxinSuperficial infection of gut, little invasion. Infective dose; 105 organisms.Yersinia enterocolitica?+/-++Fecal-oral transmission (occasionally). Food- borne in pets.Gastroenteritis or mesenteric adenitis. Occasional bacteremia. enterotoxin produced.