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Old 10-13-2011
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Bacteria Catalase negative, motility negative, H2S positive

30 YO male comes to ER with fever & shaking chills. He is toxic but alert, BP 100/65 mmHg, heart rate 110/min. The patient had hand cut, while preparing the meat as a meat handler. Blood cultures are positive for gram positive rod, that growths on aerobic blood agar with small transparent colonies. It grows on aerobic chocolate agar, small transparent colonies. No growth on MacConkey, no growth on anaerobic blood agar. Catalase negative, motility negative, H2S positive. What is the most likely causative agent?

A) Listeria monocytogenes.
B) Arcanobacterium haemolyticum.
C) Bacillus cereus.
D) Erysipelothrix rhusiopathiae.
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Old 10-13-2011
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Erysipelothrix rhusiopathiae.
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Old 10-14-2011
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It's > Erysipelothrix rhusiopathiae , and I think diagnosis is ' Erysipeloid '.
it's an occupational disease which is more common among butchers , farmers n cooks . Treatment > IM,single dose of Benzathine Benzylpenicillin or 5-7 days oral penicillin. if patient allergic to penicillin then Doxycycline or Erythromycin may be given.
Hope my answer will be right, otherwise all the above explanation will be considered as usleless
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Old 10-14-2011
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Erysipelothrix rhusiopathiae
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Old 10-14-2011
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dryogi, thnx for ur nice explanation.
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Old 10-15-2011
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The correct answer: Erysipelothrix rhusiopathiae.Erysipeloid is an occupational disease, acute bacterial infection of traumatized skin and other organs. Erysipeloid is caused by the microorganism Erysipelothrix rhusiopathiae, which long has been known to cause animal and human infections. Facultative aerobe; thin, pleomorphic gram positive rod. Zoonotic infection. Culture isolation difficult. Slow grower in enriched blood media with 5-10% CO2.
Direct contact between meat infected with E rhusiopathiae and traumatized human skin results in erysipeloid. In animals, the organism causes swine erysipelas and several other diseases in poultry and sheep. The organ most commonly affected other than the skin is the heart. The antibiotics of choice for the 3 forms of erysipeloid is penicillin or cephalosporin.
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