SHIGELLA INFECTIONS AMONG CHILDREN IN ANDAMAN - AN ARCHIPELAGO OF TROPICAL ISLANDS IN BAY OF BENGAL

Shigellosis is common among children in the Andaman and Nicobar island s. Our experience showed two distinct features of shigellosis within a span of 3 years in 1994-6. (i) changing patterns of serotype or subty pe specific shigellosis and (ii) emergence of multidrug resistant isol ates with changing R-patterns. The rate of isolation was 10.4-27.9 % w ith the rate of isolation of Shigella flexneri interchanging with S. d ysenteriae alternately. In 1994, S. flexneri superseded S. dysenteriae (48.6 % vs. 33.3 %; P < 0.05) while S. dysenteriae dominated over S. flexneri in 1995 (54.7 % vs. 34.0%; P < 0.05). The picture reversed ag ain in 1996 (63.0 % vs. 22.2 %; P < 0.05). Among shigellae isolates, t he commonest serotypes were S, dysenteriae type 1 and S. flexneri type 2a. Isolated shigellae were of multidrug resistant type. Seven R-patt erns were observed in 1994, while 8R-patterns were observed during the next year with the emergence of nalidixic acid resistance. In 1996, e mergence of gentamicin resistance was also observed. All isolates were resistant to ampicillin and sensitive to quinolones. The MIC of nalid ixic acid and gentamicin are equal to or greater than 128 mu g/ml and equal to or greater than 64 mu g/ml respectively. These changing trend s in shigellosis has important public health significance.