Detection of Extended‐Spectrum <i>β</i>‐Lactamases (ESBL) Producing Enterobacteriaceae from Fish Trapped in the Lagoon Area of Bizerte, Tunisia
Bilel Hassen, Ahlem Jouini, Monia Elbour, Safa Hamrouni, Abderrazak Maaroufi
Abstract
Extended‐spectrum β ‐lactamase and their molecular mechanism in Enterobacteriaceae were analyzed in 126 fish samples of 9 various wild species, living in the lagoon of Bizerte in Tunisia. Fifty‐nine (59) Gram‐negative strains were isolated and identified as Escherichia coli ( n = 24), Klebsiella pneumonia ( n = 21), Citrobacter freundii ( n = 8), and Shigella boydii ( n = 6). Forty‐seven ESBL producers were identified using the synergic test. β ‐Lactamase genes detected were bla CTX-M-1 ( E. coli /15; K. pneumonia /8; C. freundii /1; Sh. boydii /1), bla CTX-M-1 + bla OXA-1 ( E. coli /4; K. pneumonia /3), bla CTX-M-1 + bla TEM-1-a ( K. pneumonia /2), bla CTX-M-15 + bla TEM-1-a ( K. pneumonia /1; Sh. boydii /1), bla CTX-M-15 + bla OXA-1 ( K. pneumonia /1), bla CTX-M-15 ( E. coli /3; K. pneumonia /1; Sh. boydii /3), and bla CTX-M-9 ( C. freundii /3). Most strains (84.7%) showed a multiresistant phenotype. qnrA and qnrB genes were identified in six E. coli and in ten E. coli +one K. pneumonia isolates, respectively. The resistance to tetracycline and sulfonamide was conferred by the tet and sul genes. Characterization of phylogenic groups in E. coli isolates revealed phylogroups D ( n = 20 strains), B2 ( n = 2), and A ( n = 2). The studied virulence factor showed prevalence of fimA genes in 9 E. coli isolates (37.5%). Similarly, no strain revealed the three other virulence factors tested ( eae , aer , and cnf1 ). Our findings confirmed that the lagoons of Bizerte may be a reservoir of multidrug resistance/ESBL‐producing Enterobacteriaceae . This could lead to indisputable impacts on human and animal health, through the food chain.