Foodborne pathogens and disease最新文献

The increasing popularity of plant-based milk products as an alternative to traditional bovine milk has sparked concerns about their safety and nutritional impact. This study focuses on the growth, survival, and cryotolerance behavior of Listeria monocytogenes (strains: ATCC 19115 and RS1) in various plant-based milk substitutes. Samples of almond milk, oat milk, soy milk, and bovine milk, all subjected to ultra-high temperature treatment, were evaluated for their influence on L. monocytogenes growth at 4°C and survival through repeated freezing and thawing cycles. Despite the nutritional differences, the growth rates of two L. monocytogenes strains at 4°C in plant-based milk alternatives and bovine milk displayed similarity (p > 0.05). Both strains of L. monocytogenes demonstrated similar biofilm formation abilities in plant-based milk alternatives and bovine milk. However, L. monocytogenes exhibited different levels of tolerance to repeated freezing and thawing cycles depending on plant-based milk alternatives in which they were grown at 4°C (p < 0.05). In the case of L. monocytogenes ATCC19115, cells cultured in almond milk at 4°C showed a significant reduction in their freezing and thawing tolerance (2.80 log reduction), followed by cells grown in soy milk (2.09 log reduction) when compared with oat and bovine milk (p < 0.05). A parallel trend of tolerance was evident in L. monocytogenes RS1 (2.82 and 3.22 log reduction in almond milk and soy milk, respectively). These findings underscore the need for comprehensive assessments of microbial behavior in emerging food products like plant-based milk alternatives. As these alternatives continue to gain traction, ensuring their safety and stability remains important. With insights into L. monocytogenes growth and survival in milk alternatives, this study will contribute to the evolving understanding of microbial dynamics in response to changing dietary trends.

Unconsidered microorganisms, such as Pseudomonas aeruginosa, may be often recovered from food samples. This study aimed to characterize seven P. aeruginosa recovered from traditional market chicken meat in Lima, Peru. Antimicrobial susceptibility to 18 antimicrobial agents as well as the presence of amino acid changes in fluoroquinolone targets, 10 mediated colistin resistance (mcr) genes and integrons were analyzed. Clonal relationships were determined through pulsed-field gel electrophoresis (PFGE). Serotype by agglutination, multilocus sequence typing and the presence of 14 virulence factors (VFs) were established. Two isolates were multidrug-resistant, all being fluoroquinolone-resistant and exhibited the amino acid changes GyrA T₈₃I and ParC S₈₇L. No mcr gene was detected in the colistin-resistant isolates. The isolates showed identical PFGE patterns, and the selected P6 isolate belonged to the serotype O:4 and the sequence type 1800, and presented 12 VFs (all but exoU and exlA). The present study highlights the presence of multidrug and virulent P. aeruginosa in market chicken meat, and suggests cross-contamination during meat manipulation.

Campylobacter is one of the leading causes of bacterial foodborne diarrheal diseases throughout the world. Reported outbreaks of Campylobacter are infrequent in China. This article described such an outbreak among students from a junior high school in East China during November 2019. A total of 40 samples were collected as follows: 24 stool samples from patients, 12 stool samples from kitchen staff members, and 4 water samples from cafeteria. The stool samples were tested for the presence of Salmonella, enterotoxigenic Escherichia coli, Shigella, Vibrio parahaemolyticus, Vibrio cholera, Listeria monocytogenes, Staphylococcus aureus, Yersinia enterocolitica, Bacillus cereus, Clostridium perfringens, norovirus, rotavirus, adenovirus, astrovirus, and sapovirus by real-time polymerase chain reaction (PCR). Pulsed-field gel electrophoresis (PFGE), next-generation sequencing, and antimicrobial susceptibility testing were performed to determine the relatedness of the Campylobacter jejuni isolates in this outbreak. Forty-seven cases were reported with diarrhea among 569 seventh grade students and staff. In these 47 cases, we detected that C. jejuni through real-time PCR in 16 fecal samples was positive, whereas the remaining fecal samples were tested negative by real-time PCR. Only three C. jejuni strains were isolated from stool samples of case patients, and all of them showed 100% PFGE similarity to strain ST6913. Whole genome sequencing analysis revealed no single nucleotide variation in the three isolates. This is one of the few reports in China about outbreak caused by C. jejuni. C. jejuni ST6913 was responsible for this outbreak.

Salmonella is one of the most common causative agents of infectious diarrhea in humans, but in China, there are very limited data on the presence of Salmonella in aquatic products. This study describes the isolation of Salmonella from aquatic products in Weifang, China, from April 2022 to April 2023. Seven out of 160 (4.38%) retail aquatic product samples were positive for Salmonella. Two distinct serotypes were identified: Salmonella enterica subsp. enterica serovar Senftenberg (n = 4) and S. enterica subsp. diarizonae serovar IIIb 59:z10:z57 (n = 3). The results of molecular typing of isolates with the same serotype were consistent. Only one of the isolates was resistant to ampicillin, while the other isolates were not resistant to the tested antibiotics, suggesting that Salmonella in aquatic products in this region are relatively susceptible to antibiotics. There were 17 resistance genes in the 7 strains, 13 of which were shared. golS, MdtK, mdsA, and mdtG were unique to S. Senftenberg. A total of 155 virulence genes were annotated in the S. Senftenberg isolates, and 136 virulence genes were annotated in the S. IIIb 59:z10:z57 isolates. The S. Senftenberg isolates harbored more adhesion-related genes than the S. IIIb 59:z10:z57 isolates. Multilocus sequence typing analysis revealed that ST34 has been the most prevalent type of Salmonella in China since 2020, followed by ST11. The predominant type of Salmonella in aquaculture is ST14. This study provided additional genetic information about Salmonella in aquatic sources, providing a basis for subsequent research related to risk assessment, antibiotic resistance mechanisms, and so forth.

Rats are rodents commonly found in Thailand that carry various zoonotic pathogens. Bacterial zoonosis can occur in a shared environment between humans and rats, especially in human communities and agricultural areas. Escherichia coli, particularly pathogenic and multidrug-resistant strains, is a significant public health concern that is transmitted by rats. This study aimed to investigate the antibiotic resistance (ABR) and biofilm formation of E. coli in caught rodents from Nakhon Si Thammarat province, Thailand. Captured rats were dissected to collect intestinal content for E. coli isolation. Two hundred and two confirmed E. coli were subjected for pathotype identification, antibiotic susceptibility testing, biofilm-forming ability (BFA), and the presence of related genes. Two E. coli isolates from intestinal content samples were atypical enteropathogenic (aEPEC). Predominantly, 52.97% of E. coli had azithromycin resistance, which was harbored by 35.64% of captured rats. Multidrug resistance (MDR) was found in 12.38% of E. coli isolates with 17 different MDR patterns. Remarkably, 96% of MDR isolates were resistant to azithromycin. Most E. coli harbored ereA (52%), followed by the bla_TEM and aacC2 genes (6.44% each). Approximately 87% of isolated E. coli revealed moderate-to-high BFA. Predominantly, moderate-to-strong biofilm-forming E. coli harbored pgaA and pgaC genes. aEPEC, azithromycin resistance, MDR, and moderate-to-strong formation were the aspects of concern. Furthermore, the study of antibiotic-resistant E. coli in rats should be performed, particularly in terms of the transmission pathway, and the application of rats as bioindicators for ABR surveillance in Thailand should be established.

Listeria monocytogenes (L. monocytogenes) is a pathogen of significant concern in food due to its ability to survive and multiply under harsh environmental conditions, such as high osmotic pressure, low temperatures, and freezing. This bacterium can cause listeriosis, a severe infection particularly dangerous for high-risk groups including newborns, pregnant women, and immunocompromised patients, due to its high morbidity and mortality rates. This study aimed to investigate the molecular epidemiological characteristics of L. monocytogenes isolated in Chongqing, southwest China. A total of 72 L. monocytogenes isolates collected between 2015 and 2022 were analyzed using whole-genome sequencing (WGS). Multilocus sequence typing (MLST) revealed 15 sequence types (STs), with ST9 (20.83%), ST87 (19.44%), and ST8 (13.89%) being the most prevalent. The isolates were classified into two phylogenetic lineages and four serotypes, with serotypes 1/2b (lineage I) and 1/2a (lineage II) representing 36.11% and 41.67%, of the isolates, respectively. Antibiotic resistance gene analysis showed a high prevalence of the tetracycline resistance gene tet(M), β-lactam resistance gene blaZ, and erythromycin resistance genes msr(A), msr(D), and mef(A). All isolates contained Listeria pathogenicity islands (LIPI-1) and LIPI-2; 12 isolates carried LIPI-3, and 17 isolates carried LIPI-4, with all ST87 isolates harboring LIPI-4. The ST87 isolates were primarily sourced from meat products. These findings indicate that L. monocytogenes isolates in Chongqing harbor multiple virulence and antibiotic resistance genes, underscoring the need for ongoing surveillance and risk assessment, particularly for ST87 in meat products.

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.

Streptococcus suis is a significant zoonotic pathogen, capable of causing severe illnesses such as septicemia and meningitis in both swine and humans. Its transmission through pork consumption necessitates effective food safety measures. Lime juice, known for its antimicrobial properties, presents a potential alternative to reduce S. suis contamination in pork products. This study investigated the antibacterial efficacy of lime juice specifically against S. suis and its potential to reduce bacterial contamination in minced pork, aiming to determine optimal treatment parameters for mitigating S. suis transmission through pork consumption. Seven strains of S. suis representing serotypes known to cause zoonotic disease were cultured, and lime juice was prepared. The minimum inhibitory concentration and minimum bactericidal concentration tests consistently demonstrated the antibacterial effect of lime juice against S. suis. Survival curve analyses showed significant bacterial reduction within 15 min at 25% (v/v) lime juice concentration. In minced pork, lime juice caused a notable decrease in total bacteria and S. suis counts after 15 min. This study demonstrates the potential of lime juice as an antibacterial agent against a representative strain of S. suis in pork. However, the results also highlight that lime juice alone may not eliminate all viable bacteria. Therefore, incorporating lime juice treatment together with proper cooking practices remains crucial to ensure safe consumption of pork products.

In 2022, the U.S. Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC), and state partners conducted a sample-initiated investigation of a multistate outbreak of Salmonella Senftenberg illnesses linked to peanut butter. Twenty-one illnesses and four hospitalizations were reported in 17 states, with a significant epidemiological signal for peanut butter from Firm A. Whole genome sequence (WGS) data from a Salmonella-positive environmental swab sample collected at Firm A in 2010 yielded the outbreak strain that was a match to the WGS data from the 2022 clinical isolates. Lot code information collected from patients indicated Firm A's facility in Kentucky as a common manufacturing source, and FDA and state partners initiated an inspection. In 2021, Firm A installed two new roasters with at least one of the cooling air supply vents leaking, allowing unfiltered air and rainwater to enter the cooling section after the roasting process. Investigators noted the limitations of Firm A's finished product testing program to identify contamination. Investigative partners from five states collected and analyzed 14 product samples, and FDA collected 205 environmental swabs, and all were negative. Although the exact source and route of the contamination were not determined, epidemiological and traceback evidence confirmed peanut butter consumed by patients was produced by Firm A. Firm A voluntarily recalled all implicated products and provided a plan for corrective actions and restart to FDA. This was the first major domestic investigation of a multistate-foodborne illness outbreak linked to peanut butter since 2012. This investigation demonstrates the importance of caution with reliance on finished product testing, taking appropriate corrective actions when detection occurs, and potential benefits for industry to incorporate WGS as a tool in their environmental monitoring program.

Enterococcus spp. have been shown to have gastrointestinal tract protective functions; our recent results suggest that membrane vesicles (MVs) play an important role in the gastric protection of Enterococcus faecium (E. faecium). The specific function is determined by molecular compositions of MVs. To resolve biocargo components in E. faecium MVs (EfmMVs), MVs were isolated from E. faecium culture. Transcriptomics, label-free quantitative proteomics, and untargeted metabolomics were performed to obtain information about the complexity of ribonucleic acids (RNAs), proteins, and metabolites biocargo they carry, respectively. RNA-sequencing identified a total of 2122 transcripts. The top 20 transcripts accounted for 27.63% of total counts, which, including enzymes, participate in glycolysis, ribosomal proteins, DNA-directed RNA polymerases, protein-synthesizing relative enzymes, molecules associated with protein post-translational processing and transport, and peptidoglycan lyases. Label-free quantitative proteomics analysis identified a total of 711 proteins. The top 20 proteins accounted for 48.02% of all identified proteins, which including ribosomal proteins, enzymes participate in glycolysis, DNA-directed RNA polymerases, protein-synthesizing relative enzymes, peptidoglycan lyases, and autolysin. Untargeted metabolomics analysis identified a total of 519 metabolites. The top 20 metabolites accounted for 79.55% of all identified metabolites, which included amino acids, substrates, or products in the metabolism of amino acids, natural organic acids, products in the metabolism of organic acids, ketone compounds, and two other compounds. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses indicated that the identified biocargo components enriched in metabolism, genetic, and environmental information processing. Overall, we hope that the current exploration of multiple "-omics" analyses of this EfmMVs will provide useful information and further groundwork for future studies on E. faecium application.