Foodborne pathogens and disease最新文献

Salmonella is known to cause intestinal infections in humans, which can result in symptoms such as diarrhea, vomiting, and, in severe cases, sepsis and death. Isolates of Salmonella from specific populations and regions exhibit varying patterns of antibiotic resistance and genetic characteristics. This study aims to evaluate the diversity of 32 strains of Salmonella isolated from fecal samples of diarrhea patients in Chifeng City, China, between 2021 and 2023, through antibiotic resistance and genomic analysis. Microbroth dilution and whole genome sequencing were employed to investigate antibiotic resistance, multilocus sequence typing, phylogenetic relationship, virulence genes, antibiotic resistance genes, and mobile genetic elements. The antibiotic resistance tests showed 93.75% of Salmonella isolates were resistant to ampicillin, followed by streptomycin (STR) (87.50%) and tetracycline (TET) (56.25%). A total of 32 Salmonella strains were classified into 6 ST types. Virulence gene profiles revealed a relatively high prevalence of the type III secretion system gene cluster. The adhesion-related genes fim, Bcf, and Agf/Csg were prominently represented across all isolates. The antibiotic resistance gene profile showed that the aminoglycoside resistance gene aac(6')-Iaa (100.00%), sulfanilamide resistance gene sul (81.25%), β-lactam resistance gene blaTEM-1B (75.00%), and TET resistance gene tet (56.25%) were more commonly found. Plasmid replicons IncFII(S), IncFIB(S), IncQ1, and IncX1 were frequently identified in these isolates, serving as primary sources of horizontally acquired foreign genes. The most common phage types were Salmon_118970_sal3 (78.13%) and Phage_Gifsy_2 (59.38%). The most frequently observed insertion sequences were IS285 (56.25%) and ISEc39 (56.25%) from the IS256 family. The results indicate a correlation between the resistance phenotype of Salmonella and its genomic characteristics. These findings provide valuable references for the prevention and control of Salmonella, as well as for clinical treatment.

Camel milk is an essential nutritional resource in arid and semiarid regions and has been gaining commercial importance, particularly in the Middle East. Concerns over mycotoxin contamination, particularly aflatoxins (AFs), pose potential health risks and may affect milk quality. Understanding the role of feeding systems on the occurrence of AFs and on milk quality is vital for safeguarding public health and improving dairy industry practices. This study aimed to evaluate the impact of different feeding systems on the chemical and microbiological quality of camel milk and to detect aflatoxin M1 (AFM1) in milk and AF B1 (AFB1) in camel feed. A total of 80 samples were collected from 40 camels across Riyadh and Dammam, Saudi Arabia, between March and May 2024. Camels were divided into two groups based on feeding systems: natural grazing (grasses and legumes) and semi-intensive farm-based feeding (concentrates). Milk samples were analyzed for chemical composition and microbiological quality. Statistical comparisons were made between groups. AFB1 was detected in 1 (5%) of the natural grazing feed samples and in 3 (15%) of the farm-based feed samples; all values were below the Saudi national MRL for AFM1 in milk (0.5 μg/kg), as well as the stricter European Union's limit of 0.05 μg/kg and the Codex Alimentarius standard of 0.5 μg/kg. AFM1 was below the detection limit in all samples, and consequently, no significant differences between feeding systems could be observed. There was no significant difference in AFM1 levels between the two feeding systems. However, milk from naturally grazed camels exhibited significantly lower microbial counts. Samples from Riyadh showed no AF contamination. The absence of AFM1 in all milk samples suggests minimal public health risk. However, higher AFB1 occurrence in farm-based feed underscores the need for stringent feed monitoring. These findings inform management practices to enhance milk safety in camel dairy systems.

Salmonella can survive and contaminate food products at all stages of the pig production chain, posing a serious threat to human health. Slaughtering is an important step in controlling contamination in pigs from farms carrying Salmonella. Inadequate cleaning and disinfection in slaughterhouses can lead to Salmonella survival in carcasses and cause cross-contamination. However, studies on Salmonella prevalence in pig carcasses collected from slaughterhouses are limited. Here, we searched 13,697 documents in the database and retained 250 papers for data extraction through screening and exclusion. We then aggregated the effect size analyses to determine Salmonella prevalence in pig carcasses and on slaughterhouse equipment. The analysis showed that the overall Salmonella prevalence in pig carcasses was 10%. This analysis also suggests that feces and splitting machines are critical control points for controlling Salmonella contamination and that production processes and preventive and control measures need to be optimized and strictly implemented to reduce the spread of Salmonella in pig slaughterhouses.

Invasive non-typhoidal Salmonella (iNTS) infections pose a significant global health burden, yet comprehensive and up-to-date assessments of their worldwide impact remain limited. This study aimed to evaluate the global, regional, and national burden and trends of iNTS infections from 1990 to 2021. Data on the incidence and mortality of iNTS infections were obtained from the Global Burden of Disease (GBD) study 2021. Estimated annual percentage changes (EAPCs) were calculated to assess temporal trends, and the associations between iNTS burden and the Socio-demographic index (SDI) were analyzed. Globally, the number of iNTS incident cases increased by 46.44%, rising from 348,244 in 1990 to 509,976 in 2021. Mortality also rose by 26.72%, from 48,941 deaths in 1990 to 62,018 deaths in 2021. The global age-standardized incidence rate (ASIR) showed an overall increase (EAPC = 0.45), while the age-standardized mortality rate (ASMR) exhibited a modest annual rise of 0.2%. Significant regional disparities were observed, with Sub-Saharan Africa recording the highest ASIR and ASMR. A strong negative correlation was found between SDI and both ASIR and ASMR, although higher-SDI regions demonstrated a faster increase in ASIR. In conclusion, the global burden of iNTS infections has continued to rise over the past three decades, with notable regional inequalities. These findings highlight the urgent need for targeted interventions, improved diagnostic capacities, and strengthened surveillance of antimicrobial resistance.

Knowledge of resident bacteria present within animal food manufacturing facilities, as well as the understanding of antimicrobial resistance genes (ARGs), can help inform cleaning and sanitation practices to reduce microbial risks for the animal and human food chains. The goal of this study was to characterize resident bacteria previously isolated in selected swine feed mills within the Midwest region of the United States at multiple seasonal timepoints. About 121 resident bacterial isolates were identified and classified into six genera, consisting of 68 Enterobacter, 34 Citrobacter, four Cronobacter, eight Klebsiella, three Proteus, and four Pseudomonas, in addition to 30 Escherichia coli and 33 Salmonella characterized previously. Among the 121 isolates discussed within the current work, the majority (48; 39.7%) came from environmental samples taken from either non-feed contact surfaces such as floors and feed contact surfaces (38; 31.4%) or transient surfaces such as brooms and workers' shoes (20; 16.5%), and only 12 samples (9.9%) came directly from finished feed. A range of ARGs and metal tolerance genes (MTGs) were identified. This research provides an initial framework to understand the diversity of resident flora in feed mill facilities in the Midwest region and identify areas to focus on for housekeeping and sanitization within mills. This information is critical to developing feed safety strategies and preventing antimicrobial resistance spread in the farm-to-table continuum.

Quinolones are one of the most widely used antibiotics globally for the treatment of Staphylococcus aureus infections, and resistance to their various generations of drugs occurs. The present study aimed to investigate the inhibitory effect of quercetin on quinolone-resistant S. aureus, triggered by efflux pumps, to assess its potential value as an efflux pump inhibitor. The minimum inhibitory concentration of ciprofloxacin for resistant bacteria was determined by the micro broth dilution method, combined with UV spectrophotometry and high-performance liquid chromatography, to observe the changes in ciprofloxacin accumulation in the antibiotic-resistant bacteria after treatment with quercetin, quantitative real-time PCR (qRT-PCR) was used to analyze the transcript levels of some efflux pump genes, finally, the whole proteins of S. aureus were extracted by the action of quercetin, following bicinchoninic acid (BCA) quantification, proteins were separated by SDS-PAGE, stained with Coomassie Brilliant Blue, and overall changes in total protein bands were observed. The results showed that 64-256 µg/mL quercetin significantly increased the accumulation of ciprofloxacin in antibiotic-resistant bacteria, inhibited the efflux of ciprofloxacin by 2-10-fold downregulation of the expression of the efflux pump genes norA, norB, norC, and mepA, and modulated the protein expression profile of S. aureus. This study revealed that quercetin has the potential to act as an efflux pump inhibitor, providing a theoretical basis for the treatment of antibiotic-resistant bacterial infections.

Shigella infection is a leading cause of diarrheal diseases, especially in developing countries like Bangladesh, contributing significantly to morbidity and mortality. Despite its importance, data on Shigella prevalence, serotype distribution, and antimicrobial resistance (AMR) patterns remained limited. This study aimed to explore the prevalence of Shigella among patients with acute diarrhea at Tangail Medical College and Hospital, Tangail, Bangladesh, and to analyze the serogroup distribution and AMR profiles of the isolated strains. Stool samples from 96 patients with diarrhea were collected from May 2018 to December 2018 and tested for Shigella using biochemical, molecular, and serotyping methods. The isolates were further examined for antibiotic resistance. In addition, pathogenicity of Shigella spp. was assessed using Caenorhabditis elegans in a solid agar infection assay. Of the total participants, 28.1% were Shigella-positive by culture, while 5.2% and 4.15% were positive by molecular and serotyping methods, respectively. All Shigella isolates exhibited varying degrees of resistance to common antibiotics. Shigella flexneri isolates exhibited high resistance for nalidixic acid only among the tested antibiotics. Shigella dysenteriae was resistant to amoxicillin-clavulanic acid, erythromycin, gentamicin, and nalidixic acid, while Shigella boydii showed resistance to ampicillin, amoxicillin-clavulanic acid, and nalidixic acid. However, no resistance was observed to azithromycin, tetracycline, levofloxacin, or ciprofloxacin. In the pathogenicity assay, a significant difference in survival was observed in C. elegans infected with Shigella spp. compared with the control group. S. dysenteriae exhibited the highest pathogenicity, with only 21.6% survival of C. elegans after 12 h postinfection, while S. boydii and S. flexneri exhibited 27.47% and 35.55% survival, respectively. This study highlights the importance of regular surveillance of Shigella prevalence and AMR patterns in Bangladesh. Furthermore, exploring genomic epidemiology and alternative treatments for Shigella infections is crucial in combating its spread and resistance in Bangladesh.

Clostridium perfringens is an important zoonotic pathogen that can be carried by both humans and small ruminants. This study aimed to investigate the virulence gene profiles and antibiotic resistance characteristics of C. perfringens isolates from farmed sika deer. A total of 10 isolates were obtained from fecal samples, with an overall isolation rate of 2.59%. All strains were identified as type A. Antimicrobial susceptibility testing revealed varying degrees of resistance to tetracycline (10%), tigecycline (50%), penicillin (50%), clindamycin (50%), and metronidazole (50%). Whole-genome sequencing identified 12 virulence-associated genes (including nagK, nagH, colA, cloSI, plc, and pfoA) and 8 resistance genes (tetA(P), tetB(P), ermQ, mprF, etc.). Molecular typing by multilocus sequence typing and core genome multilocus sequence typing uncovered limited clonal spread and substantial genetic diversity, with the majority of isolates (7/10) representing novel sequence types. These findings provide new insights into the genomic characteristics of C. perfringens in farmed sika deer and underscore the potential public health and animal health risks associated with antimicrobial-resistant strains.

Shiga toxin-producing Escherichia coli (STEC) is a significant pathogen that can cause foodborne illnesses and pose a serious public health problem. To date, no systematic evaluation or meta-analysis of STEC carriage in Chinese cattle has been conducted. Therefore, we conducted a systematic review and meta-analysis to assess the prevalence of STEC in cattle in China over the past decade. We retrieved 1868 articles from 6 databases (PubMed, Web of Science, CNKI, Wanfang, VIP, and Baidu). Based on criteria such as sample source, isolation time, and species, we selected 39 studies (comprising 16,437 samples from 14 provinces) for systematic review and meta-analysis. The analysis results indicated that the pooled prevalence of E. coli in cattle during the selected time period was 6% (95% CI: 0.03-0.09). Subgroup analysis revealed variations in STEC positivity rates across different sectors. The highest positivity rate was observed in the slaughter and processing sector (12%, 95% CI: 0.03-0.17), followed by the retail sector (6%, 95% CI: 0.01-0.13), with the breeding sector showing the lowest rate (5%, 95% CI: 0.03-0.17). Among the regions studied, Shandong exhibited the highest pooled prevalence (15%, 95% CI: 0.01-0.30), followed by Hebei (12%, 95% CI: 0.00-0.30) and Hubei (11%, 95% CI: 0.03-0.09). These findings indicate an uneven distribution of STEC in cattle across China. Our systematic evaluation of data over the past decade provides insights into the prevalence of STEC in cattle in China. These findings may assist in the prevention and control of STEC in cattle in the country. We recommend conducting further epidemiological investigations and establishing comprehensive surveillance programs to identify risk factors associated with STEC in cattle, thereby enhancing prevention and control strategies.

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.