Shigellosis and Changes of Antimicrobial Susceptibility During Six Years

Background Shigellosis is a diarrheal disease caused by Shigella spp. The majority of cases and deaths occur among children less than 5 years old. In severe cases, antibiotic therapy is recommended to lessen the risk of serious complications and death. Prevalence of different Shigella species and their antibiotic resistance patterns are changing over the time. Objectives The current study aimed at assessing the changes in the prevalence of Shigella species and their antibiotic susceptibility among 0- to 14-year-old children referred to Children’s Medical Center, Tehran, Iran, from 2009 to 2014. Methods The results of stool cultures were retrospectively analyzed to determine the prevalence of different Shigella species, their antibiotic susceptibility patterns and their changes in the largest university affiliated pediatrics center in Tehran. Results Among 40 700 stool cultures, 507 cases were positive for Shigella spp. Most cases occurred among children under 5 years old. Shigellosis was more prevalent among males. The most common species were Shigella sonnei and Shigella flexneri. In general, they were most sensitive to cefotaxime and most resistant to cotrimoxazole. Resistance to cefotaxime and nalidixic acid increased annually. Resistance to ampicillin had a descending trend. Resistance to cotrimoxazole remained almost constant. Conclusions The most common species of Shigella changed from Shigella flexneri to Shigella sonnei over the years. In comparison with the previous studies, resistance to nalidixic acid increased and resistance to ampicillin decreased. The prevalence and antibiotic resistance patterns of Shigella species, at different times and regions are changing. To make appropriate decisions on treatment, it is necessary to monitor the changes.