Prevalent serogroups and antimicrobial susceptibility of Shigella strains in Metro Manila, 1982-1988

From 1982 to 1988, Shigella was detected in 4% of stool specimens cultured at The Research Institute for Tropical Medicine (RITM), Manila. S. flexneri was the most prevalent serogroup with 2a, 1b and 1a as the predominant serotypes. Isolation was most frequent during the July to December period. Drug resistance was most often observed in S. flexneri with serotype 2a exhibiting resistance to the combination of ampicillin, chloramphenicol, tetracycline and streptomycin. More multiple-drug than single-drug resistant strains were observed for the last four years. Ampicillin is still the most frequently used drug for most forms of shigellosis in the Philippines. However, the demonstration of increasing resistance among the isolates studied in RITM underscores the need to monitor antibiotic susceptibility studies and document the emergence of resistant strains in the entire country.