Virulence and multi-resistance of gram-negative bacilli strains isolated from some artisanal fermented dairy products sold in secondary schools in Benin

This work aims at assessing toxin production capability and antibiotic resistance profiles of thermo-tolerant Gram-negative bacilli strains isolated from three types of fermented dairy products (yoghurt, degue millet and degue couscous). Samples collected in Abomey-Calavi and Cotonou were analyzed for microbial, biochemical and molecular parameters. Samples were contaminated with thermo-tolerant Gram-negative bacilli strains at 13.88%. The high contamination rate was recorded with the samples of degue couscous and the lowest contaminated samples were degue millet. Morning samples were more contaminated. Klebsiella pneumoniae, Enterobacter aerogenes, Escherichia coli and Enterobacter cloacae were the most identified bacteria. The most isolated species in the dry season was E. coli. In the rainy season, K. pneumoniae and E. cloacae were the most isolated species. K. pneumoniae was the most formative of biofilm (38.9%). About 12% of the isolated strains were extended-spectrum beta-lactamases (ESBL) producers. The higher resistance rate was observed with amoxicillin and doxycylin (92.3%). Imipenem was the most efficient molecule on the isolated strains with 00% of resistance. The blaTEM gene was detected in 51.43% of the isolated strains followed by blaSHV (37.14%), blaCTX-M (8.57%) and blaOXA-1 (2.86%). It is necessary to train sales people on good hygiene practices for food during their production and their distribution.   Key words: Fermented milk products, thermo-tolerant gram-negative bacilli, toxins, antibiotics resistance, Benin.