Study of antibiotic susceptibility pattern and presence of ipaH gene among shigella strains isolated from selected provinces in Iran

Shigellosis is one of the most common causes of morbidity and mortality in children with diarrhea in developing countries. It is essential to assess the antibiotic resistance patterns of these bacteria. ipaH gene is one of the virulence factors which can be used for detection of Shigella spp.

Total of 100 isolates of Shigella were collected from different provinces of Iran. This isolates were characterized by biochemical tests and serological tests using polyclonal antisera for 4 species of S. dysenteriae, S. sonnei, S. boydii and S. flexneri. Antibiotic susceptibility assay for 14 different antibiotics was carried out using agar disc diffusion method. Presence of ipaH gene was investigated by PCR using specific primers.

From the results of this study the Shigella isolates were classified as follows: 36 (%73) Shigella sonnei, 9(%18) Shigella flexneri, 3(%5) Shigella boydii, 2(%4) Shigella dysenteriae. Approximately %50 of the Shigella isolates were resistant to Tetracycline and Cotrimoxazole. Shigella sonnei showed more resistance than other serotypes against the studied antibiotics. PCR assays showed that all isolates harbored ipaH gene.

The results showed that prevalence of Shigella sonnei is higher than other serotypes. The isolates showed high sensitivity to third generation cephalosporines and aminoglycosides. PCR detection of ipaH gene as a reliable marker for identification of Shigella species could be recommended.