Distribution of serogroups and serotypes of multiple drug resistant Shigella isolates.

SUMMARY BACKGROUND: The distribution of Shigella serotypes is of epidemiological importance and antimicrobial therapy for shigellosis can prevent potential complications of shigellosis. Studies done fifty years ago in Ghana indicated the predominance of Shigella flexneri. OBJECTIVES: To describe the distribution of Shigella serogroups and serotypes and their antibiogram profiles. STUDY DESIGN: A prospective descriptive study. SETTING: The Microbiology Department of the Korle Bu Teaching Hospital. METHODS: Consecutive stool specimens from patients with diarrhoea submitted between February 2004 and June 2005 were cultured for Shigella and the isolates typed with commercial anti-sera. The susceptibilities of the isolates were also tested against eleven antimicrobial agents by the disc diffusion method. Minimum inhibitory concentrations (MIC) of isolates to ciprofloxacin were also determined by the E-test. RESULTS: Five hundred and ninety four diarrhoea stool specimens yielded 24 Shigella isolates with the following serogroup distribution: S. flexneri 70.8%, S. dysenteriae 16.7%, S. sonnei 8.3% and S. boydii 4.2%. Approximately 96% of the isolates were multi-drug resistant but all twenty four were susceptible to nalidixic acid and the fluoroquinolones (ofloxacin and ciprofloxacin). The MICs of twenty one of the isolates to ciprofloxacin were </= 0.064 microg ml(-1). CONCLUSIONS: The predominance of S. flexneri was confirmed and Shigella isolates from Accra are susceptible to nalidixic acid and the fluoroquinolones. Surveillance of antimicrobial resistance particularly to monitor the emergence of Shigella strains resistant to nalidixic acid and the fluoroquiolones is important.