BLOODY DIARRHEA OF ADULTS IN MALAWI - CLINICAL-FEATURES, INFECTIOUS AGENTS, AND ANTIMICROBIAL SENSITIVITIES

In a prospective study, 132 hospital out-patients presenting with bloo dy diarrhoea ('cases') were evaluated in Malawi, Central Africa; 73 ou r-patient tuberculosis suspects acted as controls. Most (100/132, 76%) subjects reported an illness lasting less than or equal to 5 d with > 5 bowel actions in the preceding 12 h; 39/132 (30%) reported use of sy stemic antimicrobial drugs in the preceding week; 57% (74/130) had a b ody mass index <20; 4% (5/131) were febrile; and 18/130 (13%) had one or more sign(s) of dehydration. The 73 controls reported no diarrhoea and more systemic antimicrobial drug use (P=0.0003), but were otherwis e comparable to the subjects. All stool samples from controls and 38/1 24 (31%) from cases were macroscopically normal. Only 32% (40/124) of the cases had blood visible in the stool. Parasitic gut infections wer e found in 42/124 (34%) cases compared with 1/60 (2%) controls (P<0.00 01). The commonest parasite was Schistosoma mansoni. Bacterial culture s were positive in 32/124 (26%) of the subjects. Shigella dysenteriae (Sd) 1 accounted for 53% (17/32) of these. All bacterial isolates were sensitive in vitro to nalidixic acid and ciprofloxacin, while only 18 % were sensitive to cotrimoxazole. Sd 1 with significant antimicrobial resistance continues to cause seasonal epidemics of dysentery in Mala wi. During these, approximately two-thirds of patients presenting with bloody diarrhoea have no blood visible in the stool. Nalidixic acid r emains the drug of choice but its use should be restricted to patients at greatest risk of complicated shigellosis.