Occurrence of Extended Spectrum Cephalosporin-, Carbapenem- and Colistin-Resistant Gram-Negative Bacteria in Fresh Vegetables, an Increasing Human Health Concern in Algeria.

The aim of this study was to screen for extended spectrum cephalosporin-, carbapenem- and colistin-resistant Gram-negative bacteria in fresh vegetables in Batna, Algeria. A total of 400 samples of fresh vegetables were collected from different retail stores. Samples were immediately subjected to selective isolation, then the representative colonies were identified using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF-MS). Phenotypic and genotypic analyses were carried out in terms of species identification and relative antibiotic resistance. Transferability of the carbapenemase and -bearing plasmids was verified by conjugation. The clonal relationships of carbapenemase and -positive isolates were studied by multi-locus sequence typing (MLST). Sixty-seven isolates were characterised and were mostly isolated from green leafy vegetables, where the dominant species identified included , , , , and . PCR and sequencing results showed that was the bacterial species presenting the highest antibiotic resistance level in parallel to ( = 16) and ( = 11), which were the most detected genes. Moreover, five isolates carried carbapenemase genes, including the and/or genes. The gene was detected in two isolates. MLST analysis revealed three different sequence types: ST101 ( = 1), ST216 ( = 1) and ST2298 ( = 1). Conjugation assays confirmed the transferability of the and genes. In this study we report, for the first time, the detection of the gene in and isolates and the gene in vegetables. To the best of our knowledge, this is the first report on the detection of genes from vegetables in Algeria.