Detection of Extended-Spectrum β-Lactamases (ESBL) Producing Enterobacteriaceae from Fish Trapped in the Lagoon Area of Bizerte, Tunisia.

Bilel Hassen,Ahlem Jouini,Safa Hamrouni,Abderrazek Maaroufi,Monia Elbour

doi:10.1155/2020/7132812

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 blaCTX-M-1 (E. coli/15; K. pneumonia/8; C. freundii/1; Sh. boydii/1), blaCTX-M-1+ blaOXA-1 (E. coli/4; K. pneumonia/3), blaCTX-M-1+ blaTEM-1-a (K. pneumonia/2), blaCTX-M-15+ blaTEM-1-a (K. pneumonia/1; Sh. boydii/1), blaCTX-M-15+ blaOXA-1 (K. pneumonia/1), blaCTX-M-15 (E. coli/3; K. pneumonia/1; Sh. boydii/3), and blaCTX-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.

Highlights

The increasing rates of land-based anthropogenic pollution in marine ecosystems have become an important factor that promotes the emergence of multidrug-resistant (MDR) bacteria in aquatic animals [1,2,3]
Enterobacteria (n = 59) were isolated from 126 wild fish sampled from the Bizerte lagoon
Analysis of the sequences of the 16S rRNA genes of the 36 remaining isolates allowed the characterization of three enterobacteria species: Klebsiella pneumonia [K. pneumonia] (n = 21), Citrobacter freundii [C. freundii] (n = 8), and Shigella boydii [Sh. boydii] (n = 6)

Summary

Introduction

The increasing rates of land-based anthropogenic pollution in marine ecosystems have become an important factor that promotes the emergence of multidrug-resistant (MDR) bacteria in aquatic animals [1,2,3]. Significant antibiotics are excreted unaltered or as metabolites (up to 75%), which present a major source of antibiotic input into the aquatic environment. It is estimated that 49% of marine ecosystems worldwide are strongly affected by some anthropogenic factors of stress with significant and serious economic implications [10, 11]. Many of these compounds can be detected in water resources. Human survival and well-being depend on different services of the marine ecosystem (such as fishing) and, on the conservation and the best management of the BioMed Research International

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