ANTIBIOTIC-RESISTANCE PATTERN OF VIBRIO-CHOLERAE AND SHIGELLA CAUSINGDIARRHEA OUTBREAKS IN THE EASTERN AFRICA REGION - 1994-1996

Between March 1994 and December 1996, 1797 rectal swabs were transport ed to the AMREF laboratory from sites in six countries in the eastern Africa region: 1749 were cultured for Vibrio cholerae and 48 for Shige lla/Salmonella. Culture, isolation, identification and antibiotic susc eptibility testing were performed using standardized techniques, The i solates were categorized as sensitive or resistant based on standardiz ed zones of inhibition. The rate of isolation of V. cholerae from rect al swabs increased progressively from less than 20% to more than 45% b etween 1994 and 1996. 80-100% of isolates of V. cholerae from Kenya an d south Sudan, and 65-90% from Somalia were sensitive to tetracycline, although in 1995 isolates from Mogadishu showed only 44% sensitivity, All isolates from Tanzania and Rwanda were 100% resistant to tetracyc line, In Kenya and Somalia, the percentage of isolates sensitive to ch loramphenicol and cotrimoxazole reduced markedly from 85% in 1994 to < 10% in 1996, 100% of isolates from Rwanda and Tanzania were resistant to chloramphenicol and cotrimoxazole while in south Sudan >70% of isol ates were sensitive, Nalidixic acid and erythromycin retained >75% sen sitivity in all areas. Shigella dysenteriae and Shigella flexneri were recovered from dysentery specimens in northern Kenya. Both species sh owed similar antibiotic sensitivity patterns and were sensitive only t o nalidixic acid and furazolidone. Due to variations of resistance pat terns within countries in the region, antibiotic sensitivity testing s hould he performed at the start of an outbreak, and antibiotic use sho uld be restricted to severe cases of V. cholerae and Shigella infectio n.