Extended-Spectrum β-Lactamase, AmpC, and MBL-Producing Gram-Negative Bacteria on Fresh Vegetables and Ready-to-Eat Salads Sold in Local Markets

Abstract

We investigated the occurrence of extended-spectrum β-lactamase (ESBL), AmpC, and carbapenemase-producing Gram-negative bacteria isolated from 160 samples of fresh vegetables (n = 80) and ready-to-eat (RTE) prepacked salads (n = 80). Phenotypic and genotypic analyses were carried out on the isolates in terms of the species present and relative resistance. Resistance to β-lactam antibiotics was found in only 44 (24 from fresh vegetables and 20 from RTE salads) of a total of 312 Gram-negative strains (14.1%). The prevalence of ESBL-producing strains from fresh vegetables was 83.3% (20/24) and 16.7% (4/24) for AmpC. Among the 20 bacterial isolates from RTE salads, 80% (16/20) were identified as ESBL-producing strains and the remaining 20% (4/20) as MBL-producing strains. PCR and sequencing confirmed the presence of bla, bla, bla bla, bla, bla, bla, and bla. Seven different replicons were identified, where IncHI1, FIA, and I1 were the most representative types; when compared with the Inc types, isolates from fresh vegetables and RTE salads were similar. The location of genes on a conjugative plasmid was confirmed by positive results obtained with conjugation assays. Our study has demonstrated the occurrence and distribution of ESBL/AmpC and MBL strains in fresh vegetables and RTE salads in Italy and possible public health risks associated with consumption of these fresh products.

Characterization and Phylodiversity of Implicated Enteric Bacteria Strains in Retailed Tomato (Lycopersicon esculentum Mill.) Fruits in Southwest Nigeria

“…Occurrence of enteric bacteria strains particularly coliforms suggests fecal contamination of tomato retailed in most of these markets, initiating spoilage, reduce post-harvest shelf life and increases gastrointestinal diseases due to poor hygiene and handling from farm to the markets. This agrees with previously published reports indicating six of the Gramnegative bacteria species isolated from the fruit samples could as fecal coliforms [46], [47], [48], [49], [50], [51]. Contamination of fresh tomatoes from the farm and in the market by enteric bacteria species including Escherichia coli and other coliforms were similarly reported in postharvest tomatoes in Nigeria [11]; Ghana [52], India [53], Europe, and USA [54], [55].…”

Impact of High-Hydrostatic Pressure Treatments Applied Singly or in Combination with Moderate Heat on the Microbial Load, Antimicrobial Resistance, and Bacterial Diversity of Guacamole

“…However, we only detected bacterial growth from control samples at time 0, but not during storage or after application of HP treatments. Second, we focused on carbapenem tolerance because there is a growing concern on the dissemination of carbapenemase-producing bacteria through the food chain [21][22][23][24]. The results obtained indicated low levels of presumptive carbapenem-tolerant (cefotaxime, imipenem) enterobacteria in guacamole, but also indicated that the tolerant bacteria could persist in the sauce during refrigerated storage for up to 30-40 days.…”

“…In order to determine the impact of HP treatments on the levels of antimicrobial resistance in guacamole, we chose one representative of quaternary ammonium compounds (benzalkonium chloride) and two representatives of penem antibiotics (carbapenem and imipenem). The rationale for choosing these antimicrobials was that biocide tolerance caused by the extensive use of biocides such as quaternary ammonium compounds could be involved in coselection of antibiotic resistance [19,20] and also because of the growing concern on the dissemination of carbapenemase-producing bacteria through the food chain, not only in animal production and the environment [21,22] but also in vegetable foods [23,24]. The results of the study indicate that HP treatment remarkably changes the bacterial diversity of guacamole, with a possible additional beneficial effect related to reduction of the risks for transmission of antimicrobial resistance.…”

Heavy Metal Tolerance Trend in Extended-Spectrum β-Lactamase Encoding Strains Recovered from Food Samples

“…Microbiological risks associated with consuming ready-to-eat (RTE) food have recently become more common. Numerous outbreaks of pathogenic microorganisms demonstrate that food items are potential carriers of microorganisms that cause foodborne diseases [ 1 ]. RTE food contains pathogenic and nonpathogenic microbial flora, particularly gram-negative bacteria such as Escherichia , Vibrio , Shigella , Salmonella , Campylobacter , and Klebsiella species [ 2 , 3 ].…”