CHANGING PATTERNS OF THE PREVALENCE OF DIFFERENT SHIGELLA SPECIES ANDTHEIR ANTIBIOTIC SUSCEPTIBILITIES IN ANKARA, TURKEY

Shigella flexneri was the most common Shigella serogroup isolated in T urkey, Recently, an increase in the number of Shigella sonnei isolates was noticed, A retrospective analysis of 2,710 isolates, obtained fro m stools of Turkish children between January 1980 and September 1994, revealed that, between 1980 and 1987, S. flexneri was the most common subgroup, The isolation rate of S. sonnei increased steadily from 1987 to 1994 reaching to a peak of 78% of all isolates in 1991, The antibi otic susceptibility of 206 strains isolated in 1994 was also studied, A marked difference between the two species was observed for chloramph enicol (98% susceptibility in S. sonnei versus 20% in S. flexneri, amp icillin (90% vs. 18%), ampicillin-sulbactam (98% vs. 53%), and tetracy cline (46% vs. 18%) (p<0.001). Susceptibility to trimethoprim-sulphame thoxazole was similar between the two groups (42% vs. 38%), All isolat es were susceptible to ciprofloxacin and ceftriaxone, Comparing our re sults with resistance rates in 1989, a marked increase in ampicillin ( from 44.1% to 82%), chloramphenicol (from 36.7% to 56%) and trimethopr im-sulphamethoxazole (from 35.8% to 62%) resistance was observed.