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

Abstract

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 mcr-bearing plasmids was verified by conjugation. The clonal relationships of carbapenemase and mcr-positive Escherichia coli 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 Citrobacter freundii, Klebsiella pneumoniae, Enterobacter cloacae, Stenotrophomona maltophilia, E. coli and Citrobacter braakii. PCR and sequencing results showed that E. coli was the bacterial species presenting the highest antibiotic resistance level in parallel to blaTEM (n = 16) and blaCTX-M-15 (n = 11), which were the most detected genes. Moreover, five isolates carried carbapenemase genes, including the blaOXA-48 and/or blaVIM-4 genes. The mcr-1 gene was detected in two E. coli isolates. MLST analysis revealed three different E. coli sequence types: ST101 (n = 1), ST216 (n = 1) and ST2298 (n = 1). Conjugation assays confirmed the transferability of the blaOXA-48 and mcr-1 genes. In this study we report, for the first time, the detection of the blaOXA-48 gene in E. coli and C. braakii isolates and the blaVIM-4 gene in vegetables. To the best of our knowledge, this is the first report on the detection of mcr-1 genes from vegetables in Algeria.

Multidrug-resistant extended spectrum β-lactamase (ESBL)-producing Escherichia coli from farm produce and agricultural environments in Edo State, Nigeria

“…Our results correlate with other studies indicating vegetables as a possible route for the dynamic diffusion of AMR genes in the community [58]. The bla ESBL and other resistance genes on vegetables have been described as existing predominantly in opportunistic and saprophytic bacteria, which are thought to represent a background reservoir of antibiotic resistance genes [22].…”

“…The probable consequence of untreated irrigation water can also not be overemphasized as contributing to the spread of MDR pathogens. CTX-M-15 ESBL was detected in our study and has been identified as the most common type of ESBL in Gram-negative bacteria worldwide from different sources, including humans, animals, wildlife and wastewater samples [58].…”

“…Using contaminated irrigation water may directly link to AMR contamination, mainly if the water is applied to edible parts of fruits and vegetables [57]. The types of nutrients that are frequently present on the leaf surface of leafy green vegetables can be categorized into two: inorganic (ions) and organic molecules (organic acids and carbohydrates) [58]. Carbohydrates (dominant phyllosphere sugars are glucose, fructose and sucrose) are of particular interest due to their capacity to readily support the growth of enteric bacteria such as E. coli.…”

“…Carbohydrates (dominant phyllosphere sugars are glucose, fructose and sucrose) are of particular interest due to their capacity to readily support the growth of enteric bacteria such as E. coli. Different factors could again account for these differences, but using untreated wastewater, seasons and manure application as fertilizers might be significant factors [58]. Some authors have previously documented the identification of ESBL E. coli and the possible transmission of antibiotic-resistant bacteria via treated wastewater for irrigation [58,59], while others could not find a clear connection [60].…”

Dissemination of Carbapenemases and MCR-1 Producing Gram-Negative Bacteria in Aquatic Environments in Batna, Algeria

“…Later, OXA-48 producers were detected in several Algerian cities [ 17 ]. In Batna, the region where our study was conducted, this carbapenemase has been detected in different Enterobacterales isolates from several origins, including a hospital outbreak [ 18 ], in a hospital environment [ 19 , 20 ], in a community-acquired infection [ 21 ], in white storks [ 22 , 23 ], coins [ 24 ], pigeons [ 25 , 26 ] and fresh vegetables [ 27 ].…”