[Sensitivity to antibiotics and genetic support to resistance of Shigella flexneri strains isolated in Dakar from 2001 to 2010].

Diarrheal diseases remain a leading cause of death with 14.7 million deaths in 2001 and 26% of global mortality worldwide according to WHO. Shigella species are prevalent in tropical areas; they are present all the year, with epidemic outbreaks in rainy season. Between 2001 and 2010 one hundred ninety (190) strains of Shigella flexneri isolated from National Senegalese Enterobacteriaceae Center located at the Pasteur Institute in Dakar were studied. Susceptibility was performed by antibiogram following the CASFM recommendations. Detection and characterization of integrons and resistance genes was done by PCR using specific primers and sequencing. Antibiotic susceptibility showed high percentage resistance to tetracycline: 95%, cotrimoxazole 60%, ampicillin 55%. Nineteen strains were cephalosporin resistant (10%). Two isolates were resistant to quinolones and one was imipenem resistant. Genes tet, dfr, cat, bla tem1 , bla oxa30 , bla shv , bla CTX-M , blakpc,bla IMP , gyrA, gyrB, parC and parE were detected on isolates. Integrons harbored genes resistance. The class 1 integron predominated followed by class 2 integron. Genes bla oxa30 , aadA1/aadA2 dfrA1, dfrA7 were found on class 1 integron. Class 2 integron showed three different types cassettes. No class 3 integron was detected. Genes dfrA1, dfrA7, sat, and aadA1 were harbouring by integrons. Antibiotic susceptibility showed that Shigella flexneri strains are resistant to the first line drugs used to treat shigellosis in Senegal. Resistance to 3rd generation of cephalosporins and fluoroquinolones emerged and is of great concern. These molecules must be used with caution in the treatment of shigellosis.