Cause Of Foodborne Illness Research Articles

Predicting Salmonella MIC and Deciphering Genomic Determinants of Antibiotic Resistance and Susceptibility.

Salmonella spp., a leading cause of foodborne illness, is a formidable global menace due to escalating antimicrobial resistance (AMR). The evaluation of minimum inhibitory concentration (MIC) for antimicrobials is critical for characterizing AMR. The current whole genome sequencing (WGS)-based approaches for predicting MIC are hindered by both computational and feature identification constraints. We propose an innovative methodology called the "Genome Feature Extractor Pipeline" that integrates traditional machine learning (random forest, RF) with deep learning models (multilayer perceptron (MLP) and DeepLift) for WGS-based MIC prediction. We used a dataset from the National Antimicrobial Resistance Monitoring System (NARMS), comprising 4500 assembled genomes of nontyphoidal Salmonella, each annotated with MIC metadata for 15 antibiotics. Our pipeline involves the batch downloading of annotated genomes, the determination of feature importance using RF, Gini-index-based selection of crucial 10-mers, and their expansion to 20-mers. This is followed by an MLP network, with four hidden layers of 1024 neurons each, to predict MIC values. Using DeepLift, key 20-mers and associated genes influencing MIC are identified. The 10 most significant 20-mers for each antibiotic are listed, showcasing our ability to discern genomic features affecting Salmonella MIC prediction with enhanced precision. The methodology replaces binary indicators with k-mer counts, offering a more nuanced analysis. The combination of RF and MLP addresses the limitations of the existing WGS approach, providing a robust and efficient method for predicting MIC values in Salmonella that could potentially be applied to other pathogens.

Epidemiological characteristics of mortality from infectious intestinal diseases (diarrhea) Paraguay (2015-2019)

Introduction: Infectious intestinal diseases (diarrhea) are a major cause of morbidity and mortality worldwide. In 2015, it constituted the ninth leading cause of death for all ages. Objective: To describe the epidemiological characteristics of mortality due to infectious intestinal diseases (diarrhea) in Paraguay from 2015 to 2019. Methods: Descriptive, ecological, cross-sectional, retrospective, and non-probabilistic sampling of consecutive cases was performed. ICD-10 deaths included cholera (A01), typhoid and paratyphoid fever (A01), shigellosis (A03), other bacterial intestinal infections (A04), other bacterial food poisoning (A05), amebiasis (A06), other intestinal diseases due to protozoa (A07), intestinal infections due to viruses (A08), and diarrhea and gastroenteritis of presumed infectious origin (A09). Open access data were obtained from the WEB page of the General Directorate of Strategic Information in Health of the MSP and BS of all the Departments of the country. Crude and adjusted rates (per 100,000 inhabitants) were calculated. Excel and EPI INFO 7.0 were used. Results: 495 deaths were registered; the highest prevalence was in 2019 (adjusted rate of 1.83) and the lowest in 2017 (1.36). The months with the highest mortality rates were January and July (9.9%). 51.72% were women (256), 30.91% were over 80 years old and 28.28% (140) were under 5 years old, average age 50.8, single 56.77% (281) and without any type of education 41.82% (207). A total of 80.61% (399) of the respondents resided in urban areas. The highest rates were registered in Boquerón (33.3) and Amambay (15.2). Diarrhea and gastroenteritis of infectious origin accounted for 95.56% of the cases (473). Discussion: There was a high percentage of mortality from infectious diarrhea. Extremes of life were the most vulnerable populations.

Anti-bacterial activity of essential oils against multidrug-resistant foodborne pathogens isolated from raw milk.

The presence of pathogenic bacteria in food is considered as a primary cause of food-borne illness and food quality deterioration worldwide. The present study aimed to determine the effectiveness of five essential oils (EOs) against multidrug-resistant foodborne pathogens. In the current study Gram-negative bacteria (Escherichia, Enterobacter, Citrobacter, Proteus, Pseudomonas, and Klebsiella) and the Gram-positive bacteria Staphylococcus were isolated from raw milk and biochemically characterized. The anti-bacterial effect of different antibiotics and EOs (thyme, oregano, lemongrass, mint, and rosemary) was determined using the standard disc diffusion method. The antibiogram study revealed that Gram-negative bacteria were highly resistant to penicillin while Staphylococcus was resistant to streptomycin, amoxicillin, and lincomycin. Moderate resistance was observed to doxycycline, amikacin, enrofloxacin, kanamycin and cefixime. Isolates were found less resistant to gentamycin, chloramphenicol, and ciprofloxacin. EOs showed a broad range of antimicrobial activity against all bacteria except P. aeruginosa. Of these, thyme was more effective against most of the multi-drug resistant bacterial strains and formed the largest zone of inhibition (26 mm) against Escherichia followed by oregano oil (18 mm) against Staphylococcus (p<0.05). Klebsiella spp and Citrobacter spp showed resistance to mint and lemongrass oil respectively. The EOs such as lemongrass, mint and rosemary were less active against all the bacteria. The findings of the recent study suggest the use of EOs as natural antibacterial agents for food preservation.

Digital PCR assay for the specific detection and estimation of Salmonella contamination levels in poultry rinse

Strains of Salmonella are a frequent cause of foodborne illness and are known to contaminate poultry products. Most Salmonella testing methods can qualitatively detect Salmonella and cannot quantify or estimate the Salmonella load in samples. Therefore, the aim of this study was to standardize and validate a partitioned-based digital PCR (dPCR) assay for the detection and estimation of Salmonella contamination levels in poultry rinses. Pure culture Salmonella strains were cultured, enumerated, cold-stressed for 48 h, and used to inoculate whole carcass chicken rinse (WCCR) at 1–4 log CFU/30 mL and enriched at 37 °C for 5 h. Undiluted DNA samples with primer and probes targeting the Salmonella-specific invA gene were used for the dPCR assay. The dPCR assay was highly specific, with a limit of detection of 0.001 ng/μL and a limit of quantification of 0.01 ng/μL. The dPCR assay further showed no PCR reaction inhibition up to 5 μg of crude DNA extract. The assays accurately detected all cold-stressed Salmonella in inoculated WCCR samples following a 5-h enrichment. Most importantly, when converted to log, the dPCR copies/μL values accurately estimated the inoculated Salmonella levels. The dPCR assay standardized in this study is a robust method for the detection and estimation of Salmonella concentration in contaminated food samples. This approach can allow same-day decision-making for poultry processors attempting to maintain limits and controls on Salmonella contamination.

Inactivation of Salmonella Enteritidis in liquid egg yolk and egg white using bacteriophage cocktails

Salmonella Enteritidis (SE) is a significant global cause of foodborne illness, often linked to egg contamination. This study evaluated the inhibitory effects of eight bacteriophages (phages) against three SE strains isolated from poultry environments. The most effective phages were selected to formulate different phage cocktails, to enhance the efficacy and prolong inhibition. Four phage cocktails were tested at a multiplicity of infection (MOI) of 100 in tryptic soy broth (TSB), and at MOIs of 100 and 1000 in liquid egg white (EW) and egg yolk (EY) with storage at 8 °C for up to 30 days (d). The effectiveness of the phage cocktails varied significantly among bacterial strains, yet all demonstrated significant reductions compared to the positive control in liquid culture (P < 0.05). Similarly, the tested SE strains in both EW and EY showed significant reductions with phage treatments (P < 0.005), although the effectiveness was influenced by the MOI and medium composition. Treating EY proved to be more challenging, with lower magnitudes of reduction and longer treatment durations required, compared to EW. Reductions ranged from 1 to greater than 4 log CFU/mL in EW and EY after 30 d, with consistently higher reductions achieved at MOI 1000. Phage titers decreased initially, but remained stable following SE inoculation in broth and liquid eggs at 8 °C, indicating that lysis from without mechanisms may have contributed to the inhibitory effect. Notably, phages exhibited stronger attachment to SE in EW, which can be attributed to be less viscous nature of EW compared to EY. This study demonstrated that phage applications in both EW and EY effectively reduced SE counts at 8 °C, with no regrowth during long-term storage. These findings contribute to the development of biocontrol methods that enhance food safety and reduce foodborne outbreaks associated with contaminated egg products.

Addressing Current Challenges in Poultry Meat Safety: Development of a Cultivation and Colony Hybridization Approach to Recover Enterotoxigenic Clostridium perfringens from Broiler Chicken Carcasses.

Enterotoxigenic Clostridium perfringens is one of the main causes of foodborne illness in Canada. The use of a conventional bacterial culture approach to isolate enterotoxigenic C. perfringens from poultry meat is common. This approach is based on the phenotype attributable to a double hemolysis phenomenon, whereas few enterotoxigenic strains of C. perfringens produce it, which further complicates the study of the reservoirs of this important pathogen. The objectives of the current study were to validate the ability of a digoxigenin-labeled probe to detect the C. perfringens cpe gene and to validate the use of either a filtration or a direct plating approach, combined with colony hybridization to detect enterotoxigenic C. perfringens. Pure DNA and pure colonies of enterotoxigenic C. perfringens and broiler chicken carcass rinsate samples were subjected to colony hybridization. The results showed that the synthesized DNA probe can detect the cpe gene from both DNA and pure colonies of enterotoxigenic C. perfringens, and from colonies grown from carcass rinsates artificially contaminated with enterotoxigenic C. perfringens. Our study suggests that this isolation method is a promising tool for a better understanding of the epidemiology of this zoonotic pathogen.

Inclusion of trans-cinnamaldehyde and caprylic acid in feed results in detectable concentrations in the chicken gut and reduces foodborne pathogen carriage

Poultry act as a major reservoir host for Salmonella and Campylobacter spp., the 2 leading causes of foodborne illnesses globally and in the United States. Preharvest stage interventions to reduce foodborne pathogen carriage in poultry are increasingly informed by consumer preference for antibiotic-free poultry production. The in-feed inclusion of plant-derived antimicrobial compounds is a promising antibiotic alternative strategy to reduce foodborne pathogen load in the broiler chicken gut. Yet, the fate of these phytochemicals through the broiler chicken gastrointestinal tract is unknown. Likewise, while in-feed phytochemicals have been widely demonstrated in challenge models to reduce foodborne pathogen carriage, little is known regarding efficacy to curb natural routes of infection. As such, the aim of the present study was 2-fold. We sought to determine the concentrations of 2 phytochemicals, trans-cinnamaldehyde and caprylic acid, in each region of the chicken gastrointestinal tract following their in-feed inclusion over a 6-wk production period. In addition, we investigated how the in-feed provision of these phytochemicals may protect against environmental acquisition of Campylobacter jejuni and Salmonella spp. Trans-cinnamaldehyde and caprylic acid were detected in crop, gizzard, duodenal, jejunal, and ileal contents. Crop and gizzard concentrations were not significantly (P > 0.05) different. A significant (P < 0.05) decrease in phytochemical concentration was observed in intestinal regions compared to crop and gizzard. Trans-cinnamaldehyde was consistently identified in cecal and colon contents, while caprylic acid was not detectable in these regions. Trans-cinnamaldehyde and caprylic acid were found to reduce (P < 0.05) Salmonella load. Together, our data establish that the in-feed addition of trans-cinnamaldehyde and caprylic acid, 2 phytochemicals that have previously been shown to exert antimicrobial activity against poultry-associated foodborne pathogens, results in detectable concentrations in the broiler chicken gastrointestinal tract. By providing researchers with a gastrointestinal region-by-region map of phytochemical concentrations, the present study is expected to inform the choice of in-feed phytochemicals targeting foodborne pathogen carriage in the broiler chicken gastrointestinal tract.

Egg-associated Salmonella enterica serovar Enteritidis: comparative genomics unveils phylogenetic links, virulence potential, and antimicrobial resistance traits.

Salmonella enterica serovar Enteritidis (SE) remains a frequent cause of foodborne illnesses associated with the consumption of contaminated hen eggs. Such a food-pathogen association has been demonstrated epidemiologically, but the molecular basis for this association has not been explored. Comparative genomic analysis was implemented to decipher the phylogenomic characteristics, antimicrobial resistance, and virulence potential of eggs-associated SE. Analyzing 1,002 genomes belonging to 841 sequence types of food-isolated SE strains suggests a high genomic similarity within the egg-related lineage, which is phylogenetically close to SE strains isolated from poultry but is different from those isolated from beef. Core genome- and single nucleotide polymorphism (SNP)-based phylogeny of 74 SE strains of egg origin showcased two distinct sublineages. Time-scaled phylogeny supported the possibility of a common ancestor of egg-related SE lineages. Additionally, genome mining revealed frequent antibiotic resistance due to the presence of aac(6')-Iaa and mdsAB encoded on the genomes of egg-associated SE strains. For virulence gene profiling, 103-113 virulence determinants were identified in the egg-associated SE, which were comparable to 112 determinants found in human-associated SE, emphasizing the capacity of egg-associated strains to infect humans and cause diseases. The findings of this study proved the genomic similarity of egg-associated SE strains, and these were closely related to poultry strains. The egg-associated strains also harbor virulence genes equivalent to those found in human-associated SE strains. The analysis provided critical insights into the genetic structure, phylogenomics, dynamics of virulence, and antibiotic resistance of Salmonella Enteritidis, circulating in eggs and emphasizing the necessity of implementing anti-Salmonella intervention strategies, starting at the production stage of the poultry supply chain.

Systematic Review and Meta-Analysis of Campylobacter Species Contamination in Poultry, Meat, and Processing Environments in South Korea.

Campylobacter spp. constitute a significant global threat as a leading cause of foodborne illnesses, with poultry meat as a prominent reservoir for these pathogens. South Korea is known for its diverse poultry consumption habits, and continuous outbreaks make it a matter of concern to perform a meta-analysis to identify the primary source of contamination. This systematic review and meta-analysis aimed to assess and compare the prevalence of Campylobacter in various poultry and meat types while also considering the importance of environmental factors in South Korea. The meta-analysis revealed that duck meat exhibited the highest prevalence of Campylobacter, with a pooled estimate of 70.46% (95% CI: 42.80% to 88.38%), followed by chicken meat at a pooled prevalence of 36.17% (95% CI: 26.44% to 47.91%). Additionally, our analysis highlighted the predominance of C. jejuni and C. coli in South Korea. These findings underscore the importance of implementing rigorous food safety measures and establishing robust surveillance programs in the poultry industry to mitigate the risk of Campylobacter-related foodborne illnesses associated with meat consumption in South Korea.

Genotyping and antibiotic susceptibility of Campylobacter species isolated from raw milk samples in Qazvin, Iran

ObjectiveCampylobacter species are major causes of foodborne illnesses, with unpasteurized milk being a significant carrier of these bacteria, posing a public health risk. One of the challenges in managing Campylobacter infections is the emergence and spread of antibiotic resistance. We conducted a study in Qazvin, Iran, testing 84 raw cow’s milk samples to determine the frequency of C. jejuni and C. coli using culture-based and multiplex PCR methods. Additionally, the disk diffusion and RAPD-PCR approaches were utilized to evaluate the phenotypic antibiotic resistance profile and genetic diversity of Campylobacter strains.ResultsThe findings indicated that Campylobacter spp. was present in 19.05% of the samples, with C. coli being the predominant isolate. We tested eight antibiotic agents, and the resistance levels of the isolates were as follows: erythromycin 100%, tetracycline 75%, doxycycline 56.25%, ceftriaxone 43.75%, chloramphenicol 37.5%, amoxicillin-clavulanic acid 25%, nalidixic acid 12.5%, and azithromycin 6.25%. Genetic diversity analysis categorized Campylobacter isolates into 39 clusters, indicating a wide diversity among strains. However, no significant correlation was observed between antibiotic resistance and cluster patterns. These findings underscore the role of raw milk as a reservoir for Campylobacter spp. and highlight the substantial antibiotic resistance and genetic diversity within the species population.

Virulence factors and antimicrobial resistance profiles of Campylobacter isolates recovered from consecutively reused broiler litter.

Campylobacter is a leading cause of foodborne illness in the United States due to consumption of contaminated or mishandled food products, often associated with chicken meat. Campylobacter is common in the microbiota of avian and mammalian gut; however, acquisition of antimicrobial resistance genes (ARGs) and virulence factors (VFs) may result in strains that pose significant threat to public health. Although there are studies investigating the genetic diversity of Campylobacter strains isolated from post-harvest chicken samples, there are limited data on the genome characteristics of isolates recovered from preharvest broiler production. Here, we show that Campylobacter jejuni and Campylobacter coli differ in their carriage of antimicrobial resistance and virulence factors may also differ in their ability to persist in litter during consecutive grow-out of broiler flocks. We found that presence/absence of virulence factors needed for evasion of host defense mechanisms and gut colonization played an integral role in differentiating Campylobacter strains.

A foodborne outbreak linked to Bacillus cereus at two middle schools in a rural area of Chongqing, China, 2021.

Bacillus cereus (B. cereus) is a common cause of foodborne illness. An outbreak of acute gastrointestinal illness occurred at two middle schools in a rural region of Chongqing, China, in 2021. This study aimed to elucidate the outbreak's characteristics, identify risk factors, and determine the source of contamination. A retrospective cohort study and an environmental investigation were conducted. Vomit samples, anal swabs, and food samples were collected and tested by RT-PCR for 18 species of bacteria and viruses, including B. cereus. Positive samples of B. cereus underwent biochemical experiments and bacterial quantification. A total of 198 cases were reported in this outbreak, with an attack rate of 24.63%. The main symptoms were vomiting (100%), bellyache (83.33%), and dizziness (62.63%). The retrospective cohort study showed a significant association between the outbreak and rice noodles provided by a nearby food manufacturer (RR = 39.63, p < 0.001). B. cereus was detected in 20 vomit samples, three anal swabs, and seven rice noodles samples, with a count exceeding 103 CFU/g. These findings strongly suggested that the outbreak was linked to B. cereus-contaminated rice noodles. Enhancing food safety surveillance and promoting health measures among schools and food manufacturers in rural areas is crucial to prevent similar incidents in the future in Chongqing, China.

The Socioeconomic Factors of Street Food Vending in Developing Countries and Its Implications for Public Health: A Systematic Review.

The sale of ready-to-eat (RTE) street food represents an important source of income in many developing countries. However, these foods are frequently implicated in outbreaks of gastrointestinal diseases. Street food vendors face several constraints that hamper improvement in the microbiological quality of their products. The aim of this review was to update knowledge about the main causes of foodborne illnesses in developing countries, including the growing concern with the microbial transmission of antibiotic resistance. Following PRISMA guidelines, this systematic review was conducted on original articles published from January 2010 to July 2023. The search was carried out using Scopus, PubMed, Web of Science, Food Science and Technology Abstracts (FSTA), the International Information System for Agricultural Sciences and Technology (AGRIS), as well as isolated searches of relevant articles from Google Scholar. The initial search identified 915 articles, 50 of which were included in this systematic review. The results indicate that, in the majority of the 15 countries examined, women constitute the predominant segment of street food vendors, representing more than 55% of the total number of these vendors. In 11 countries, street food vendors under the age of 18 were identified. Most vendors had a low level of education and, consequently, were unaware of good hygiene practices when handling food. The combination of factors such as poor hygiene practices on the part of food handlers and the lack of facilities, namely, the absence of available potable water, were frequently listed as the main causes of food contamination. Enterobacteriaceae such as Escherichia coli (61.9%), Salmonella (30.1%), and Shigella spp. (9.5%), as well as Staphylococcus aureus (30.1%) and Listeria monocytogenes (14.3%), were the most common pathogens found in RTE street foods. In 22 studies from 13 developing countries, 59% (13/22) reported high multidrug resistance in Enterobacteriaceae (40% to 86.4% in E. coli, 16.7 to 70% in Salmonella, and 31 to 76.4% in S. aureus). To address the challenges faced by street vendors and improve their economic activities, it is necessary for government entities, consumers, and vendors to work together collaboratively.

Shiga toxin-producing Escherichia coli (STEC) in meat and leafy greens available in the Swedish retail market – Occurrence and diversity of stx subtypes and serotypes

Shiga toxin-producing Escherichia coli (STEC) is a major cause of foodborne illness, ranging from mild diarrhea to permanent kidney failure. This study summarizes the results of four surveys performed at different time periods, which investigated the occurrence and characteristics of STEC in beef, lamb and leafy greens available in the Swedish retail market. Such data is required when assessing the public health risk of varying types of STEC in different foods, and for establishing risk management measures. Samples from domestic and imported products were collected based on their availability in the retail market. The occurrence of STEC was investigated in 477 samples of beef, 330 samples of lamb and 630 samples of leafy greens. The detection of virulence genes (stx1, stx2, eae) was performed using real-time PCR followed by the isolation of bacteria from stx-positive enriched samples using immunomagnetic separation or an immunoblotting method. All STEC isolated from the food samples was further characterised in terms of stx subtyping and serotyping through whole genome sequencing. STEC was isolated from 2 to 14 % of beef samples and 20 to 61 % of lamb samples, depending on the region of origin. STEC was not isolated from samples of leafy greens, although stx genes were detected in 11 (2 %) of the samples tested. In total, 5 of the 151 sequenced STEC isolates from meat contained stx2 and eae, of which 4 such combinations had the stx2a subtype. The stx2 gene, stx2a in particular, is strongly associated with serious disease in humans, especially in combination with the eae gene. The isolates belonged to 20 different serotypes. Two isolates from beef and one from lamb belonged to the serotype O157:H7 and contained genes for stx2 and eae. Overall, several combinations of stx subtypes were found in isolates from beef, whereas stx1c, either alone or together with stx2b, was the dominant combination found in STEC from lamb. In conclusion, STEC was rare in whole meat samples of domestic beef in the Swedish retail market, whereas such bacteria were frequently found in minced meat and whole meat samples of imported beef and domestic and imported lamb. Although the number of isolates containing genes linked to an increased risk of severe disease was low, beef and lamb in the Swedish retail market is a common source of human exposure to potentially pathogenic STEC.

Controlling Multi-Drug-Resistant Traits of Salmonella Obtained from Retail Poultry Shops Using Metal-Organic Framework (MOF) as a Novel Technique.

Salmonella spp. is considered one of the most important causes of food-borne illness globally. Poultry and its products are usually incriminated in its spread. Treatment with antibiotics is the first choice to deal with such cases; however, multi-drug resistance and biofilm formation have been recorded in animals and humans. This study aimed to detect the antibiotic profile of isolated traits from different sources and to find innovative alternatives, such as MOFs. A total of 350 samples were collected from randomly selected retailed poultry shops in Beni-Suef Province, Egypt. Their antimicrobial susceptibility against eight different antibiotics was tested, and multi-drug resistance was found in most of them. Surprisingly, promising results toward MOF were detected. Cu/Ni/Co-MOF (MOF3) showed superior antibacterial efficiency to Cu/Ni-MOF (MOF2) and Cu-MOF (MOF1) at p value ≤ 0.01. These findings highlight the tendency of Salmonella spp. to develop MDR to most of the antibiotics used in the field and the need to find new alternatives to overcome it, as well as confirming the ability of the environment to act as a source of human and animal affection.

Microbial Analysis of Fresh Fruit Juice Available in the Market

Juices made from fresh fruits that were improperly prepared are one of the main causes of food borne illnesses. In this study, the microbial qualities of some freshly prepared fruit juices were assessed. A total of 200 fresh fruit juice samples of mango, pineapple, orange, pomegranates and sugarcane were collected. The pour plate method was used to determine the total viable count of the sample. The pathogenic bacteria investigated were Bacillus E. coli, S. aureus, Lactobacillus, Acetobactor, Salmonella and Shigella using appropriate growth media. Aspergillus niger, Aspergillus flavus, Penicillium sp., Fusarium, Colleotrichum and Alternaria are the predominant moulds found in fruit juices. Yeast isolates such as Saccharomyces, Candida and Rhodotorula were also observed in freshly prepared fruit juices. It was found that sugarcane and orange juices were highly contaminated with microbes. Fungal contamination was dominant over bacterial contamination. It has been determined that the microbial load in fresh fruit juices is significantly greater than the normal permissible limits, suggesting that it may play an important role in food spoilage and food-borne illnesses. There is a need for some regulations that can improve the quality of fruit juices because some of the microorganisms found in these juice samples can cause disease in human and also produce mycotoxins which cause cancer.

The characteristics of mcr-bearing plasmids in clinical Salmonella enterica in Sichuan, China, 2014 to 2017.

Salmonella is one of the most important zoonotic pathogens and a major cause of foodborne illnesses, posing a serious global public health hazard. The emergence of plasmid-mediated mcr genes in Salmonella has greatly reduced the clinical choice of salmonellosis treatment. The aim of this study was to investigate the plasmid characteristics of mcr-positive Salmonella identified from patients in Sichuan, China during 2014 to 2017 by whole genomes sequencing. In this study, a total of 12 mcr-positive isolates (1.15%, ; mcr-1, n=10; mcr-3, n=2) were identified from 1046 Salmonella isolates using PCR. Further characterization of these isolates was performed through antimicrobial susceptibility testing, conjugation assays, whole genome sequencing, and bioinformatics analysis. The mcr-1 gene in these isolates were carried by three types of typical mcr-1-bearing plasmids widely distributed in Enterobacteriaceae (IncX4, IncI2 and IncHI2). Of note, two mcr-1-harboring IncHI2 plasmids were integrated into chromosomes by insertion sequences. Two mcr-3-bearing plasmids were IncC and IncFIB broad-host-range plasmids respectively. Genetic context analysis found that mcr-1 was mainly located in Tn6330 or truncated Tn6300, and mcr-3 shared a common genetic structure tnpA-mcr-3-dgkA-ISKpn40. Overall, we found that mcr gene in clinical Salmonella were commonly carried by broad-host plasmids and have potential to transfer into other bacteria by these plasmids. Continuous surveillance of MDR Salmonella in humans and investigation the underlying transmission mechanisms of ARGs are vital to curb the current severe AMR concern.

Oxigenic Profiling and Antibiotic Resistance of Baclllus cereus Strains Isolated from Food Consumed By School Children In Ilorin Metropolis

Background: Food poisoning is caused by toxin produced by pathogenic organisms like bacteria, viruses etc. These toxins are common causes of food borne illness. This study was carried out to determine the antibiotic susceptibility pattarn and molecular identity of enterotoxigenic Bacillus cereus strains isolated from food consumed by school children in Ilorin metropolis Methods: Bacterial isolates that were identified as Bacillus cereus (OQ235070), Bacillus cereus (OQ235071), Bacillus cereus (OQ235072), Bacillus cereus (OQ235073), Bacillus thuringiensis (OQ235074), Bacillus cereus (OQ235075) and Bacillus cereus (OQ235076) were obtained from culture collection from Microbiology laboratory, Kwara State University, Nigeria were used for this research. Antibiotic susceptibility test was carried out on the isolates using standard technique. Detection of resistance gene, plasmid profiling and curing, and detection of enterotoxigenic genes were done using standard microbiological methods. Results: All the isolates were resistant to minimum of two antibiotics before and after plasmid cur-ing. A total of 98 % of the isolates were susceptible to ofloxaxin, centamincin, pefloxacin, and augmentin while 90 % of the isolates were resistance to amoxylin, streptomycin, and chloramphenicol. Plasmid profiling shows that the bacteria harbored mega plasmid with equal size of 5000 bp. Curing removed all plasmid, presence of enterotoxin virulence gene nhe A, B, C and hbl C, D were observed but hbl A was not found. Conclusion: The Bacillus species studied were found to be multi-drug resistant and carried entero-toxigenic genes which were chromosomally borne.

Differences in the Shiga Toxin (Stx) 2a Phage Regulatory Switch Region Influence Stx2 Localization and Virulence of Stx-Producing Escherichia coli in Mice.

Shiga toxin (Stx)-producing Escherichia coli (STEC) is a major cause of foodborne illness globally, and infection with serotype O157:H7 is associated with increased risk of hospitalization and death in the U.S. The Stxs are encoded on a temperate bacteriophage (stx-phage), and phage induction leads to Stx expression; subtype Stx2a in particular is associated with more severe disease. Our earlier studies showed significant levels of RecA-independent Stx2 production by STEC O157:H7 strain JH2010 (stx2astx2c), even though activated RecA is the canonical trigger for stx-phage induction. This study aimed to further compare and contrast RecA-independent toxin production in Stx2-producing clinical isolates. Deletion of recA in JH2010 resulted in higher in vitro supernatant cytotoxicity compared to that from JH2016ΔrecA, and the addition of the chelator ethylenediaminetetraacetic acid (EDTA) and various metal cations to the growth medium exacerbated the difference in cytotoxicity exhibited by the two deletion strains. Both the wild-type and ΔrecA deletion strains exhibited differential cytotoxicity in the feces of infected, streptomycin (Str)-treated mice. Comparison of the stx2a-phage predicted protein sequences from JH2010 and JH2016 revealed low amino acid identity of key phage regulatory proteins that are involved in RecA-mediated stx-phage induction. Additionally, other STEC isolates containing JH2010-like and JH2016-like stx2a-phage sequences led to similar Stx2 localization, as demonstrated by JH2010ΔrecA and JH2016ΔrecA, respectively. Deletion of the stx2a-phage regulatory region in the wild-type strains prevented the differential localization of Stx2 into the culture supernatant, a finding that suggests that the stx2a-phage regulatory region is involved in the differential ΔrecA phenotypes exhibited by the two strains. We hypothesize that the amino acid differences between the JH2010 and JH2016 phage repressor proteins (CIs) lead to structural differences that are responsible for differential interaction with RecA. Overall, we discovered that non-homologous stx2a-phage regulatory proteins differentially influence RecA-independent, and possibly RecA-dependent, Stx2 production. These findings emphasize the importance of studying non-homologous regulatory elements among stx2-phages and their influence on Stx2 production and virulence of STEC isolates.

Modeling the risk of Vibrio parahaemolyticus in oysters in Taiwan by considering seasonal variations, time periods, climate change scenarios, and post-harvest interventions

Vibrio parahaemolyticus is a halophilic gram-negative bacterium commonly found in marine environments, particularly in warm coastal waters. This pathogen has been reported as a common cause of foodborne illness associated with the consumption of raw or undercooked seafood. The presence and density of this bacterium in seafood are often associated with the climatological conditions of the marine environment. Herein, we developed the quantitative risk assessment model for Vibrio parahaemolyticus in oysters in Taiwan by considering seasonal variations, time periods, climate change scenarios, and post-harvest interventions. This study showed that season, time period, shared socioeconomic pathway (SSP), and post-harvest intervention significantly influenced the risk level of becoming ill from consuming oysters. The mean estimates of risk in winter, spring, summer, and fall were estimated to be 9.1 × 10−5, 2.0 × 10−3, 2.0 × 10−2, 6.9 × 10−3 per serving, respectively. Our models predict that, if global temperatures continue to increase in the coming decades due to climate change, the risk per serving of oysters is likely to increase by 18-145% by 2041-2060 and by 18-718% by 2081-2100, depending on the season and SSP. The application of thermal processing or high hydrostatic pressure processing was found to be the most effective approach in reducing risk, even under the threat of increasing global temperatures.