THE MOLECULAR EPIDEMIOLOGY OF TRIMETHOPRIM-SULFAMETHOXAZOLE-RESISTANCE OF SHIGELLA-FLEXNERI IN THE TRAKYA REGION OF TURKEY

Trimethoprim-sulphamethoxazole (SXT) resistance increased among Shigel la flexneri isolates in 1995 relative to previous years, in the Trakya region, the European part of Turkey. Since this region is the entranc e to Turkey from northern countries, a heavy traffic of travellers pas sing through should have been importing or exporting the resistant iso lates. We studied the genetic basis and epidemiology of this resistanc e and monitored the clonal changes which have taken place in the meanw hile. During the study period, a total of 70 Shigella spp. were isolat ed. Of these 58 were S. flexneri, 10 were S. sonnei and two were S. bo ydii. S. dysenteriae was not isolated. Of S. flexneri isolates 32 were SXT, ampicillin, chloramphenicol and tetracycline resistant (pattern I), while two isolates were found to be resistant only to SXT (Pattern II). Transconjugation experiments revealed that an approximately 80 K bp self-transmissible plasmid carried the SXT resistance genes in both groups. However, EcoRI and HindIII restriction patterns of the plasmi ds from resistance pattern I and resistance pattern II were different. Ribotypes of three randomly selected isolates from pattern I were ide ntical and were distinguishable from the ribotype of the isolate from pattern II. We concluded that at least two different clones with diffe rent plasmids and resistance patterns were spreading in our territory.