Biochemical and AntiBiogramic Study for Resistance Strains of Salmonella spp. Isolated from Leafy Vegetables in the Market Garden in N'Djamena, Chad

Abstract

Salmonellosis is one of the most frequently reported foodborne illnesses and the majority of salmonellosis in humans comes from fresh fruits and vegetables. The objective of this work is to assess the level of contamination and to determine the biochemical profile and susceptibility to antibiotics of the strains of Salmonella spp. isolated from leafy vegetables produced in market garden farms in N'Djamena in Chad. 144 samples from six (6) different types of leafy vegetables were collected and analyzed according to standard food microbiology methods. ISO 6579 (2002) was used for microbiological analysis. The classical identification gallery and the API 20E gallery allowed the biochemical identification of isolated strains. The Kirby-Bauer method was used to test the antibiotic susceptibility of strains of Salmonella spp. The results obtained show microbiological contamination of vegetables analyzed in particular rocket and lettuce with a proportion of Salmonella spp. of 12.50% and 8.33% respectively. However, contamination varies according to the sites and is intimately linked to the poor bacteriological quality of irrigation water. The study determined the biochemical characteristics of each isolate. On the other hand, the susceptibility profiles of strains to antibiotics were varied. Indeed, the antibiotic sensitivity test of the isolates showed that the strains of Salmonella spp isolated are much more resistant to ceftriaxone, ampicillin and chloramphenicol. The most active antibiotics were amoxicillin/ clavulanic acid, nalidixicic acid, ciprofloxacin and imipenem with a sensitivity rate above 80%. However, the resistance of Salmonella spp to certain antibiotics is a real public health problem that challenges the authorities in charge of the issue.