First description of class 1 integron in typhoidal Salmonella isolated from clinical and lettuce samples in Burkina Faso.

Abstract

Background: In Burkina Faso, dirty water, in particular those of the stoppings and the gutter are used for irrigation of vegetables. The aim of this study is to contribute to the knowledge on the molecular level of Salmonella circulating in the hospitals and environment next to hospitals in Burkina Faso. Methods: Salmonella isolated from diarrhea stools between 2009 to 2015 and lettuce samples isolated in 2014 in Burkina Faso were characterized by simple Polymerase Chain Reaction using specific primers. Sequencing was performed using the BigDye terminator protocol on the ABI PRISM 310. The sequences obtained corresponding were searched using the BlastN program.Results: Out of 100 Salmonella isolated, 53% were from human and 47% from lettuce samples. Globally, the highest prevalence was observed with invA, misL, pipD, orfL and spvR genes in 97%, 96%; 74%; and 21%. Forty of these isolates carried class 1 integron, 31 from clinical samples and 9 from lettuce samples. Sequencing showed different gene with aadA1 in 13/15 strains, aadA7 and aac(3)-Id in 2/15 strains. Eight percent (8/100) of Salmonella harbored gyrB and parE genes. Sequencing showed no mutation in these genes. Three distinct Pulsed-Field Gel Electrophoresis (PFGE) types were observed from clinical samples with 90-95% similarity in each case. All Salmonella from lettuce had similar pulsotypes. Conclusion: This study showed that lettuce is a potential source of transmission of Salmonella causing diarrhea among human in Burkina Faso.