Serodiversity and antimicrobial resistance pattern of Shigella isolates at Gondar University teaching hospital, Northwest Ethiopia.

The aims of this study were to determine the distribution of serogroups and serotypes as well as the antimicrobial resistance pattern of Shigella isolates from Gondar patients with acute diarrhea. A cross-sectional study was conducted from August 2006 to February 2008. Stool specimens were received from study subjects and cultured. Isolates were confirmed by biochemical and serological tests. The isolates were tested for antimicrobial susceptibility by the disc diffusion method. Of the 1,200 stool specimens, 90 (7.5%) yielded Shigella isolates with the serogroups of Shigella flexneri (72.2%), S. dysenteriae (10.0%), S. boydii (8.9%), and S. sonnei (8.9%). S. flexneri was the predominant serogroup. S. dysenteriae type 1 was absent, and S. sonnei was present. Eighty-five (94.5%) of the isolates showed resistance to one or more drugs, and 79% of those were multi-resistant. S. flexneri showed the highest resistance (91.2%). S. flexneri serotype 1, resistant to ciprofloxacin and norfloxacin, was observed. All isolates were sensitive to nalidixic acid and ceftriaxone. Only 5 (5.6%) of the isolates were sensitive to all antibiotics tested. Based on these findings, we recommend ciprofloxacin as the drug of choice for treatment of shigellosis in Gondar, with frequent monitoring of drug susceptibility testing.