Foodborne pathogens and disease最新文献

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.

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.

In recent years, the wild deer population in Japan has grown exponentially, causing severe feeding damage to the agricultural and forestry industries. Therefore, the game meat industry is being promoted for effective utilization of hunted animals. Wild animals are not hygienically controlled and can serve as reservoirs for pathogenic microorganisms. However, epidemiological information on wild animals in Japan remains insufficient. Recently, food poisoning-like cases have occurred because of raw venison infection with Sarcocystis spp. As the prevalence of Sarcocystis spp. in sika deer is very high in Japan and even fawns are infected, this study attempted to verify the vertical infection of Sarcocystis spp. in sika deer in Japan. Genetic detection of Sarcocystis 18S ribosomal RNA in fetal and maternal tissues from early to late gestation in sika deer revealed Sarcocystis Types 1-5 and Sarcocystis fayeri in the mother and fetus. Types 1, 2, 4, and 5 were detected in the maternal tissues of Ezo sika deer (Cervus nippon yesoensis) in Hokkaido, whereas Types 1 and 2 and S. fayeri were detected in fetuses. Types 1-5 were detected in Honshu sika deer (Cervus nippon centralis) in Mie Prefecture but not in the fetuses. Types 1, 2, and 4 were detected in the udder and milk samples. This indicates that Sarcocystis Types 1 and 2 and S. fayeri have the ability to pass through the placenta of sika deer and invade fetal tissues and Types 1, 2, and 4 may be transmitted orally via milk. These findings suggest that there is transplacental and transmammary transmission of Sarcocystis spp. in sika deer.

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.

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.

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.

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.