CHARACTERISATION OF CLINICAL SHIGELLA ISOLATES, USING SEROTYPING AND ANTIMICROBIAL RESISTANCE PROFILES IN ZIMBABWE

Objective: The study was conducted to determine the species distribution and antimicrobial susceptibility patterns of Shigella species obtained from clinical samples (feaces, urine & blood). Design: This was a cross sectional analytical study. Settings: The study was conducted between August 2016 and May 2017 at the National Microbiology Reference Laboratory (NMRL), Harare and National University of Science and Technology (NUST), Applied Biology and Biochemistry Department in Zimbabwe. Isolates: A total of 123 stored Shigella isolates were obtained from the NMRL and all isolates were confirmed as Shigella using serology and PCR. Speciation of Shigella isolates was done using serology. Antimicrobial susceptibility testing was performed on all the isolates using the disc diffusion assay and antibiotic resistance genes were detected using conventional PCR. The isolates stored at NMRL were collected from different provinces around Zimbabwe. Results: S. flexneri was found to be the most prevalent species 87(71%) followed by S. sonnei 18(14%), S. boydii 11(9%) and S. dysenteriae 7(6%). A total of 115 isolates (93.5%) were resistant to two or more drugs suggesting wide spread multi-drug resistance (MDR). Twenty six multi-drug resistance patterns were observed. The most common patterns (resistance to trimethoprim-sulfamethoxazole, tetracycline, ampicillin and chloramphenicol) were exhibited by 28(24.3%) isolates for both combinations. Shigella was mainly isolated from stool samples: 112[S. flexneri (89.7%), S. sonnei (94.4%), S. dysenteriae (90.9%) and S. boydii (8%)] as compared to urine (4.6%, 5.6%, 9.1% and 0%) and blood (5.7%, 0%, 0%, 0%) respectively. Fourteen isolates (11.4%) were positive for the bla TEM, bla SHV and bla CTX-M genes or a combination. Conclusion: The observed high multidrug resistance could hamper treatment of shigellosis in Zimbabwe. GSJ: Volume 7, Issue 1, January 2019 ISSN 2320-9186 780 GSJ© 2019 www.globalscientificjournal.com