Foodborne pathogens and disease最新文献

Staphylococcus aureus and a few species of coagulase negative are frequently associated with food poisoning. Raw milk and dairy products are among the foods usually associated with outbreaks due to staphylococcal intoxication. This study aimed to determine phenotypic and genotypic antimicrobial resistance profiles to beta-lactam drugs in Staphylococcus coagulase positive (CoPS) and negative (CoNS) isolates. A total of 58 CoPS and 45 CoNS isolates recovered from raw milk and artisanal cheese from Santa Catarina were analyzed. All isolates (n = 103) were subjected to antimicrobial susceptibility testing. High levels of resistance to penicillin (41% of CoPS and 31% of CoNS), amoxicillin (40% CoPS), ampicillin (36% CoPS), and sulfamethoxazole-trimethoprim (35% CoNS) were observed. Twenty six percent of the isolates (18 CoPS and 9 CoNS) exhibited multiresistance profile; which means, they were resistant to at least three different classes of the antimicrobial drugs. Detection of resistance genes (mecA, mecC, and blaZ) was performed using multiplex polymerase chain reaction. Twelve isolates (9 CoPS and 3 CoNS) were positive for mecA, whereas 10 strains (4 CoPS and 6 CoNS) were positive for blaZ. The detection of resistant and multidrug resistant isolates emphasizes the necessity to develop strategies to better comply with good manufacturing practices and health care guidelines.

The objective of this study was to examine changes in healthcare-seeking behaviors and diagnostic practices around foodborne illness during the COVID-19 pandemic in a large university-based health system. A retrospective cohort study of individuals diagnosed with pathogens commonly transmitted through food between 2015 and 2020 was undertaken using electronic medical record data. Regression models were used to compare measured incidence rates of various foodborne pathogens as well as associated healthcare-seeking behaviors during the pandemic year of 2020 to previous years. Incidence of campylobacteriosis, cholera, and norovirus in 2020 significantly decreased, respectively, by 65.5% (p < 0.01), 90.1% (p = 0.02), and 73.0% (p = 0.03) compared with an average from 2017- to 019. Average annual visits for patients included in our sample significantly increased by 8.0% when comparing the average from 2017-2019 to 2020 (p < 0.01). These results suggest that the pandemic impacted healthcare use related to foodborne disease either due to reduced exposure to foodborne pathogens or reduced willingness to seek healthcare.

Because of the medical importance of cumin as well as it being one of the food additives to many Saudi dishes, there was a need to study the fungal load of this type of spice. This study aimed to determine the mycological profile of the retail black and green cumin distributed in different markets at western region, Saudi Arabia, using the dilution plat method on dichloran 18% glycerol (DG18) agar and incubation at 25°C. Using morphological criteria and molecular markers (internal transcribed spacer sequence), 39 species belonging to 18 genera were collected from different black cumin (33 species belonging to 17 genera) and green cumin (25 species belonging to 9 genera). Alternaria alternata, Aspergillus flavus, A. niger, A. ochraceus, Cladosporium cladosporioides, and Stemphylium botryosum were the most prevalent. Black cumin harbors fungal counts reaching 545 colony-forming units (CFU)/g, while green cumin included 500 CFU/g. Also, the natural occurrence of aflatoxins and ochratoxin A was also measured. Seventy-two cumin samples (90% of tested samples) showed toxin contamination. Aflatoxins and ochratoxin A ranged from 9.35 to 3.9 PPB in black cumin samples and from 4.08 to 5.75 PPB in green cumin samples.

In this study, sea buckthorn polysaccharides (SBP) were added as functional substances to chitosan (CS), and chitosan/sea buckthorn polysaccharide (SCS) composite films were prepared using the casting method. The effects of SBP addition on the optical properties, physical properties, mechanical properties, structure, antioxidant activity, and antibacterial activity of the SCS composite films were studied, and the prepared SCS composite films were used to preserve yellow cherry tomatoes. The results showed that SCS composite films exhibited good UV resistance, water solubility, and antioxidant activity, but its apparent structure, hydrophobicity, and mechanical properties needed further improvement. Meanwhile, SBP has inhibitory effects on all 8 experimental strains. In addition, the SCS composite film with the addition of 200 mg/L SBP could reduce the weight loss rate of yellow cherry tomatoes, maintain hardness, delay the decrease of total soluble solids, titratable acid, and Vitamin C content, and inhibit the accumulation of malondialdehyde. SCS composite films are beneficial for enhancing the quality of yellow cherry tomatoes during storage, and their application in fruit and vegetable preservation has development prospects.

Staphylococcus aureus contamination and prevention has always been a major concern for food industry. This work investigated the antibacterial activity and mechanisms of lauric acid (LA) against S. aureus. Results revealed 156 μg/mL was the minimum inhibitory concentration (MIC) for LA and it retarded growth rate of S. aureus. The inhibitory effect was enhanced with LA concentration. After being treated with 2 MIC LA for 24 h, the number of S. aureus decreased by 3.56 log colony-forming unit (CFU)/mL. Scanning electron microscopy profiling revealed that LA resulted in altered morphology of S. aureus cells. In addition, propidium iodide staining of flow cytometry suggested that LA treatment disrupted the cell membrane integrity. Changes in 8-anilino-1-naphthalenesulfonic acid fluorescence indicated a depolarization change in cell membrane fluidity. For practical applications, LA also displayed an antimicrobial potential in cooked chicken food model system, with 1.25-5 g/L of LA prolonging shelf life by 2 days at 4°C. Moreover, it had no adverse effect on pH values, color in cooked chicken meat, and even reduced lipid oxidation. To sum up, LA has great antimicrobial properties and is a candidate preservative for cooked meat food.

Effectively managing foodborne pathogens is imperative in food processing, where probiotics play a crucial role in pathogen control. This study focuses on the Lactiplantibacillus plantarum AR113 and its gene knockout strains, exploring their antimicrobial properties against Escherichia coli O157:H7 and Staphylococcus aureus. Antimicrobial assays revealed that the inhibitory effect of AR113 increases with its growth and the potential bacteriostatic substance is acidic. AR113Δldh, surpassed AR113Δ0273&2024, exhibited a complete absence of bacteriostatic properties, which indicates that lactic acid is more essential than acetic acid in the bacteriostatic effect of AR113. However, the exogenous acid validation test affirmed the equivalent superior bacteriostatic effect of lactic acid and acetic acid. Notably, AR113 has high lactate production and deletion of the ldh gene not only lacks lactate production but also affects acetic production. This underscores the ldh gene's pivotal role in the antimicrobial activity of AR113. In addition, among all the selected knockout strains, AR113ΔtagO and ΔccpA also had lower antimicrobial effects, suggesting the importance of tagO and ccpA genes of AR113 in pathogen control. This study contributes insights into the antimicrobial potential of AR113 and stands as the pioneering effort to use knockout strains for comprehensive bacteriostatic investigations.

Goats are often asymptomatic carriers of Campylobacter, including the foodborne pathogen Campylobacter jejuni. Infections can have significant and economically detrimental health outcomes in both humans and animals. The primary objective of this study was to estimate the prevalence of Campylobacter in U.S. goat herds. Campylobacter species were isolated from 106 of 3,959 individual animals and from 42 of 277 goat operations that participated in fecal sample collection as part of the National Animal Health Monitoring System Goat 2019 study. Weighted animal-level prevalence was 2.3% (SE = 0.5%) and operation prevalence was 13.0% (SE = 3.2%). Animal-level prevalence ranged widely from 0 to 70.0%, however, 52.4% of positive operations (22/42) had only a single isolate. C. jejuni was the most frequently isolated species (68.9%; 73/106), followed by C. coli (29.3%, 31/106). A total of 46.2% (36/78) of viable isolates were pan-susceptible to 8 antimicrobials. Resistance to tetracycline (TET) was observed in 44.9% (35/78) of isolates, while 12.8% (10/78) were resistant to ciprofloxacin (CIP) and nalidixic acid (NAL). Among all isolates, a single resistance profile CIP-NAL-TET was observed in 3.8% (3/78) of isolates. A total of 35 unique sequence types (STs) were identified, 11 of which are potentially new. Multiple C. jejuni STs were observed in 48.1% (13/27) of positive operations. Goats with access to surface water, operations reporting antibiotics in the feed or water (excluding ionophores and coccidiostats), and operations reporting abortions and without postabortion management tasks had significantly greater odds of being Campylobacter positive. This snapshot of the U.S. goat population enriches the limited pool of knowledge on Campylobacter species presence in U.S. goats.

This study aimed to understand the epidemiological characteristics of Salmonella in Tibetan pigs. We isolated, identified, and examined via antimicrobial susceptibility testing on Salmonella from Tibetan pigs breeder farms and slaughterhouses in Tibet, China. A genetic evolutionary tree was constructed on the basis of whole genome sequencing (WGS). A total of 81 Salmonella isolates were isolated from 987 samples. The main serovars were Salmonella Typhimurium and Salmonella London in Tibetan pigs. The isolated Salmonella Typhimurium isolates subjected to antimicrobial susceptibility testing showed varying degrees of resistance to β-lactams, aminoglycosides, fluoroquinolones, sulfonamides, tetracyclines, and amphenicols. WGS analysis was performed on 20 Salmonella Typhimurium isolates in Tibet (n = 10), Jiangsu (n = 10), and 205 genome sequences downloaded from the Enterobase database to reveal their epidemiological and genetic characteristics. They were divided into two clusters based on core genome single-nucleotide polymorphisms: Cluster A with 112 isolates from Tibet and other regions in China and Cluster B with 113 isolates from Jiangsu and other regions. The isolates in Cluster A were further divided into two subclusters: A-1 with 40 isolates including Tibet and A-2 with 72 isolates from other regions. Virulence factors analysis revealed that all isolates from Tibet carried adeG, but this observation was not as common in Salmonella isolates from Jiangsu and other regions of China. Antibiotic resistance genes (ARGs) analysis showed that all isolates from Tibet carried bla_TEM-55 and rmtB, which were absent in Salmonella isolates from Jiangsu and other regions of China. Genetic characteristic analysis and biofilm determination indicated that the biofilm formation capabilities of the isolates from Tibet were stronger than those of the isolates from Jiangsu and other regions of China. Our research revealed the epidemic patterns and genomic characteristics of Salmonella in Tibetan pigs and provided theoretical guidance for the prevention and control of local salmonellosis.

Cronobacter species are potential pathogens that can contaminate powdered infant formula. C. sakazakii and C. malonaticus are the most common species of Cronobacter associated with infections. This study mined new molecular targets for the detection of C. sakazakii and C. malonaticus by using comparative genome approaches. Specific target genes mngB and ompR were obtained and used to detect C. sakazakii and C. malonaticus, respectively. A novel detection method, termed ladder-shape melting temperature isothermal amplification (LMTIA), was developed and evaluated. The detection limit for pure C. sakazakii DNA was 1 pg per reaction and 1 fg per reaction for C. malonaticus. The C. sakazakii, C. malonaticus, and the reference stains were all correctly identified. The amplicons can be successfully visualized and identified by naked eyes when hydroxy naphthol blue dye (HNB dye) was used in the reaction. Therefore, the LMTIA assays developed in this study showed potential application for microorganism identification and detection.

Listeria monocytogenes, one of the main foodborne pathogens, is commonly found in milk and dairy products. This study aimed to estimate the presence of L. monocytogenes in milk and dairy product supply chains using a meta-analysis based on PubMed, Embase, Web of Science, and Scopus databases. A total of 173 studies were included in this meta-analysis. The pooled prevalence in the supply chain environment was 8.69% (95% confidence interval [CI]: 5.30%-12.78%), which was higher than that in dairy products (4.60%, 95% CI: 1.72%-8.60%) and milk products (2.93%, 95% CI: 2.14%-3.82%). Subgroup analysis showed that L. monocytogenes prevalence in raw milk (3.44%, 95% CI: 2.61%-4.28%) was significantly higher than in pasteurized milk (0.60%, 95% CI: 0.00%-2.06%). The highest prevalence of L. monocytogenes in milk and dairy products was observed in North America (5.27%, 95% CI: 2.19%-8.35%) and South America (13.54%, 95% CI: 3.71%-23.37%). In addition, studies using culture and molecular methods (5.17%, 95% CI: 2.29%-8.06%) had higher prevalence than other detection methods. Serogroup 1/2a and 3a (45.34%, 95% CI: 28.74%-62.37%), serogroup 1/2b and 3b (14.23%, 95% CI: 6.05%-24.24%), and serogroup 4b/4e (13.71%, 95% CI: 6.18%-22.83%) were dominant in these studies. The results of this study provide a better understanding of the prevalence of L. monocytogenes in milk and dairy product supply chains and suggest a potential foodborne pathogen burden.