Foodborne pathogens and disease最新文献

Nontyphoidal Salmonella presents a significant threat to animal and human health as a food-borne infectious agent. This study focused on the characterization of Salmonella isolates obtained from fresh animal products consumed in Bejaia, Algeria. In total, 495 beef products, 600 chicken products, and 355 dairy products were collected from retail outlets and slaughterhouses in the region. Out of the 1450 samples collected, a Salmonella positivity rate of 3.5% (51/1450) was observed. Traditional Algerian sausages exhibited the highest prevalence of Salmonella contamination (14.1%, 36/256). Fifteen different serotypes were identified, with S. Kentucky (n = 12), S. Anatum (n = 11), and S. Bredeney (n = 9) being the most prevalent. Antimicrobial susceptibility testing showed resistance to diverse antibiotics, particularly against tetracycline, ampicillin, nalidixic acid, and sulphonamides. Whole-genome sequencing conducted on 21 isolates enabled the comparison of phylogenetic links between isolates. We notably identified clones circulating across the region in different locations and food types, suggesting contamination at the early stages of the food chain (in the herd or slaughterhouses) that disseminated to numerous butcher shops in various cities. We also identified acquired antibiotic resistance genes and point mutations in the quinolone resistance-determining region genes, contributing to the observed resistance patterns. This study describes the genomic and phylogenetic characteristics of several Salmonella clones found in diverse food samples in Algeria. It suggests potential transmission dynamics that could better understand Salmonella's contamination routes.

During the COVID-19 pandemic, nonpharmaceutical public health interventions (NPIs) were implemented worldwide to control the spread of severe acute respiratory syndrome coronavirus 2. However, the incidence of other pathogens, including gastrointestinal (GI) pathogens, was also affected. Here, we reviewed studies assessing the impact of NPIs during the COVID-19 pandemic on the incidence of GI infections, particularly foodborne infections. A systems literature search was conducted in May 2023, using Living Evidence on COVID-19 (COAP) and Scopus. Articles were identified and selected through a screening process with inclusion and exclusion criteria based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. Data were extracted from each full-text article included in the review. Parameters included were GI viruses, GI bacteria, NPIs against the COVID-19 pandemic, and the associated impact of NPIs on GI pathogens. A total of 42 articles were included in the review, representing 18 countries. Overall, a larger reduction was observed for viral GI infections compared with bacterial GI infections during the COVID-19 pandemic, particularly for norovirus. For bacterial GI infections, Campylobacter and nontyphoidal Salmonella were the most frequently detected pathogens in the majority of the studies, with the largest reduction observed for Shigella and Shiga toxin-producing Escherichia coli infections. The sharp decrease in GI viral infections in most of the included countries is suggested to be related to the disruption of person-to-person transmission due to several implemented interventions (e.g., social distancing and hand hygiene). GI bacterial pathogens, more commonly transmitted via the foodborne route, were least impacted, and their reduction is associated with closure of food-providing settings and travel restrictions. However, the observed changes appear to be multifactorial; alterations in health-care-seeking behaviors and in routinary diagnostic testing have undeniably played a significant role, affecting national surveillance systems. Therefore, although NPIs likely had a substantial impact on the burden of GI infectious diseases, the extent of the true change cannot be fully assessed.

Avian pathogenic Escherichia coli (APEC) is an important bacterial pathogen that causes severe respiratory and systemic infections in poultry. Our previous research investigated the prevalence and antimicrobial resistance phenotypes of APEC isolated from poultry flocks in Jiangxi Province, China. The present study aims to further identify the serotypes and the carbapenem-resistant gene bla_NDM in APEC strains. Serotype investigations revealed that the most dominant serotype was O24 (53.2%), followed by O78 (11.9%), O2 (3.2%), O18 (2.4%), O45 (0.8%), and O88 (0.8%). Serotypes O1, O30, and O65 were not detected, and 35 strains (27.8%) were un-typed. The identified genes bla_NDM-5 and bla_NDM-1 shared a close phylogenetic distance with Klebsiella sp. and Acinetobacter sp. isolated from river and human feces, respectively. Two APEC strains carrying bla_NDM-5 and bla_NDM-1 were subjected to whole-genome sequencing and analysis. The results showed that bla_NDM-5 was associated with the mobile genetic element IS5 and bla_NDM-1 was associated with the mobile genetic element ISAba125. Current study findings can be helpful for effective vaccine development and provide a deep understanding of APEC infections and antimicrobial resistance in poultry flocks.

Quorum sensing (QS) is a bacterial communication system regulating virulence, biofilm formation, and antimicrobial resistance via autoinducer signaling molecules. Disrupting QS, known as quorum quenching (QQ), represents a promising strategy for controlling bacterial pathogenicity without promoting antibiotic resistance. This study aimed to screen lactic acid bacteria (LAB) isolated from diverse fermented foods for QS inhibition (QSI) activity using Chromobacterium violaceum ATCC 12472 as a biosensor. Among 208 LAB isolates, only 11 strains inhibited violacein production, indicative of significant QSI activity. Further assessment with cell-free culture supernatants revealed that isolate WPL10 demonstrated the highest violacein inhibition at 18.4%. In contrast, 28 isolates exhibited weak activity, and the remaining 169 showed no inhibitory effect. The most active isolate, identified as Lactiplantibacillus plantarum WPL10 via Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometer (MALDI-TOF MS), showed promising QQ potential likely mediated by metabolic products or enzymatic mechanisms. This research highlights fermented foods as valuable sources of natural QQ agents and identifies L. plantarum WPL10 as a potential biocontrol agent for improving food safety by reducing bacterial virulence and biofilm formation.

Peracetic acid (PAA) is extensively used in poultry processing, but its bactericidal mechanism remains poorly understood. Reactive oxygen species (ROS) are linked to bacterial cell death by many bactericidal agents. This study investigated the role of ROS in PAA against Salmonella Typhimurium 14028 using bacterial suspensions treated with PAA alone (20 ppm), PAA combined with 2,2'-dipyridyl (Dip; iron chelator) or with thiourea (ROS scavenger) followed by incubation at 37°C for 1 h. Post-incubation, serial dilutions were plated on Luria-Bertani agar to determine colony-forming units per milliliter. Additionally, eight single-deletion mutants and the wild-type (control) of Salmonella Typhimurium 14028 were tested for survivability after exposure to PAA (treatment; 20 ppm) and hydrogen peroxide (H₂O₂; control). The mutants were categorized by predicted ROS impact: increase in ROS production (atpC, gnd, nuoG, pta, sdhC, and zwf) and no change in ROS production (negative control; edd and pykA). Finally, rifampicin-based selection assay was utilized to evaluate the mutation rate of the wild-type strain in the presence of PAA (60 ppm), H₂O₂ (control), and PAA + thiourea. Treatment with 20 ppm PAA significantly (p < 0.05) reduced the viability of Salmonella Typhimurium 14028 by a log₁₀ reduction of 0.34, while co-treatment with thiourea restored counts to control level. The survival of the mutants predicted to increase ROS production was significantly reduced compared with the control mutants and wild-type strain (p < 0.05). Exposure to sublethal PAA led to a 28-fold increase in mutation rate suggesting the production of ROS by PAA was responsible for the observed increase. ROS production is a significant component of PAA's bactericidal activity against Salmonella Typhimurium, and increasing ROS production might be exploited to enhance PAA-mediated killing of Salmonella Typhimurium. ROS production by PAA can lead to the development of antibiotic resistance in Salmonella Typhimurium when cells manage to escape cell death.

Antimicrobial resistance in livestock products poses an important public health threat globally. This study aimed to evaluate the antimicrobial resistance profiles and trends of Enterococcus faecium and Enterococcus faecalis isolated from food animal carcass samples during 2014-2023 in South Korea. The obtained 1632 E. faecium and 3493 E. faecalis isolates from cattle, pig, and chicken carcasses at the national level were tested for antimicrobial susceptibility using broth microdilution. E. faecium and E. faecalis isolates from chickens showed higher resistance rates to most evaluated antimicrobials compared with cattle or pig strains. E. faecium isolated from chickens showed high levels of resistance to ciprofloxacin, erythromycin, and tetracycline by >50%. Likewise, over 40% of the E. faecalis isolates recovered from chickens exhibited resistance to these antimicrobials. Of note, very few or no enterococci isolates were resistant to ampicillin, gentamicin, linezolid, and vancomycin. Furthermore, notwithstanding fluctuations, enterococci strains showed an increasing resistance trend to some antimicrobials, including erythromycin and streptomycin. E. faecium exhibited significantly greater multidrug resistance (MDR) rates in chickens compared with cattle and pig isolates, while MDR E. faecalis was higher in pigs and chickens than in cattle isolates (p < 0.05). The main components of the resistance patterns were erythromycin, ciprofloxacin, or tetracycline. Moreover, MDR patterns in E. faecalis (23.4%) and E. faecium (17.8%) include five or more antimicrobials. The MDR enterococci contaminating carcasses during the slaughtering of food animals can be spread to humans through the food chain, posing a potential hazard to public health. Thus, judicious use of antimicrobials and proper sanitary measures are essential to mitigate the risk of transmission.

Pseudomonas is a common food spoilage bacterium that can cause spoilage of milk, eggs, fish, and other food products under low temperature conditions. In this study, a total of four Pseudomonas phages were isolated from spoiled fish and shrimp, and the biological characterization of one of them, Pseudomonas psychrophila phage P-2FD, which exhibited a wider host spectrum, was carried out. Morphological analyses showed that phage P-2FD belonged to the Podoviridae family and the Caudovirales order. When the multiplicity of infection (MOI) was 1000, the growth of P. psychrophila was almost completely inhibited before 9 h. When phage P-2FD treated P. psychrophila in grass carp with an MOI of 1000, the bacterial counts were reduced by 1.77 log₁₀ CFU/g compared with the control group at 4°C for 96 h, indicating that phage P-2FD effectively inhibited the growth of P. psychrophila. Genomic analysis showed that P-2FD was a novel phage, and the whole genome length of P-2FD was 40,453 bp with 42 open reading frames (ORFs). The phage endolysin LysP-2FD was expressed in Escherichia coli BL21 (DE3) and purified, and the lytic rate against P. psychrophila was 78.17% at a concentration of 20 μmol/L. The present study suggests that phage P-2FD and endolysin can be used as potential antimicrobial agents for the control of P. psychrophila in the food industry.

This study developed a rapid detection method for Salmonella based on real-time recombinase polymerase amplification (real-time RPA). The method exhibited excellent specificity and could amplify target genes within 20 min at 39°C. It achieved a Limit of Detection (LOD₅₀) of 47 CFU/mL. To evaluate detection performance, artificially contaminated food samples-including egg products, chocolate products, meat products, grain-based products, and soy products-were tested. Prior to real-time RPA detection, the samples underwent an enrichment step by shaking incubation at 36°C for 6 h. The real-time RPA method demonstrated consistent and robust performance across diverse food matrices, with relative LOD (RLOD) values below 2.5, satisfying the validation criteria outlined in GUOBIAO 4789.45 (GB 4789.45). A chi-square test conducted on bulk pork samples further confirmed no significant difference between the real-time RPA method and the GB 4789.4 standard method (p > 0.05). These findings highlight the potential of real-time RPA as a reliable and efficient alternative to GB 4789.4 for detecting Salmonella, enhancing food safety monitoring practices.

Since 2020, more than 2000 illnesses have been linked to foodborne outbreaks associated with onions. In 2023, the U.S. Food and Drug Administration (FDA), the Centers for Disease Control and Prevention, and state partners investigated a multistate outbreak of Salmonella Thompson infections linked to diced onions grown and processed in California. The outbreak resulted in 80 ill people, 18 hospitalizations, and one death reported in 23 states. FDA conducted a traceback investigation that included three illness clusters comprised of five total ill people from four Long-Term Care Facilities. Three inspections, each accompanied by sampling, were conducted at Processor A, Grower A, and Packing Shed A, respectively. The FDA analyzed 18 samples, six of which yielded Salmonella spp. isolates. Isolates recovered from water, sediment, and piping below irrigation equipment, near the growing environment, matched the outbreak strain. Additional isolates recovered from environmental samples matched eight Salmonella Saintpaul clinical isolates from 2022, four Salmonella Infantis clinical isolates from four states from 2022 to 2023, and two unrelated Salmonella Newport clinical clusters from 2021 to 2023. Laboratory, traceback, and epidemiological evidence indicated onions grown in three specific fields as the source of the outbreak, suggesting that the outbreak strain was present at the farm level, established in the soil, and potentially disseminated through agricultural water. Further processing into diced onions could have also spread and/or amplified the pathogen in the product due to the practices and conditions at the processor. This investigation highlighted the importance of outreach and education to enhance onion industry food safety practices and prevent future outbreaks. It also emphasized the need for focused research on onion industry practices, including growing, harvesting, curing, processing, packing, and holding.

Vibrio fluvialis is an emerging foodborne pathogen associated with severe infections. In this study, immunomagnetic beads (IMBs) were synthesized by conjugating nanobody N71 to magnetic nanoparticles (MNPs) via polyethylenimine (PEI) and glutaraldehyde (GA) cross-linking. Due to the high affinity of N71 for V. fluvialis lipopolysaccharide, the IMBs efficiently and specifically captured the target pathogen. When integrated with ToxR-targeted quantitative real-time PCR, this system achieved enhanced detection sensitivity (48 CFU/mL) and reduced false-positive rates. The optimization results showed that the capture efficiency of V. fluvailis reached its maximum (95%) when 125 µg of N71 were conjugated to 1 mg of MNPs to form the MNPs-PEI-GA-Nbs conjugates, achieved with a conjugate dosage of 0.5 mg and an incubation time of 45 min. Nontarget bacterial interference experiments and actual sample detections validated the excellent specificity of the method for detecting V. fluvialis. Compared with conventional culture-based methods, this method reduced detection time from 24-48 h to <7 h, providing an efficient and reliable alternative for rapid detection of V. fluvialis in food samples.