Stx2 Genes Research Articles

A Cross-Sectional Survey on Ready-to-Fry Falafel Regarding Its Potential to be Host for Escherichia coli, Staphylococcus aureus, and sea, stx1, stx2 Genes Responsible for Toxin-Origin Food Poisoning

A Cross-Sectional Survey on Ready-to-Fry Falafel Regarding Its Potential to be Host for Escherichia coli, Staphylococcus aureus, and sea, stx1, stx2 Genes Responsible for Toxin-Origin Food Poisoning

Gastrointestinal involvement in STEC-associated hemolytic uremic syndrome: 10 years in a pediatric center

BackgroundThe gastrointestinal (GI) tract represents one of the main targets of typical hemolytic uremic syndrome (HUS) in children. In this observational study, we tried to establish (1) the main features of GI complications during STEC-HUS and (2) the relationship between Escherichia coli serotypes and Shiga toxin (Stx) variants with hepatopancreatic involvement.MethodsA total of 79 STEC-HUS patients were admitted to our pediatric nephrology department between January 2012 and June 2021. Evidence of intestinal, hepatobiliary, and pancreatic involvements was reported for each patient, alongside demographic, clinical, and laboratory features. Frequency of gastrointestinal complications across groups of patients infected by specific E. coli serotypes and Stx gene variants was evaluated.ResultsSix patients developed a bowel complication: two developed rectal prolapse, and four developed bowel perforation which resulted in death for three of them and in bowel stenosis in one patient. Acute pancreatitis was diagnosed in 13 patients. An isolated increase in pancreatic enzymes and/or liver transaminases was observed in 41 and 15 patients, respectively. Biliary sludge was detected in three, cholelithiasis in one. Forty-seven patients developed direct hyperbilirubinemia. Neither E. coli serotypes nor Shiga toxin variants correlated with hepatic or pancreatic involvement.ConclusionsDuring STEC-HUS, GI complications are common, ranging from self-limited elevation of laboratory markers to bowel perforation, a severe complication with a relevant impact on morbidity and mortality. Hepatopancreatic involvement is frequent, but usually short-lasting and self-limiting.Graphical abstractA higher resolution version of the Graphical abstract is available asSupplementary information

Investigating the presence and antibiotic susceptibilities of Escherichia coli O157 and Listeria monocytogenes in ruminant feces and feed in Balıkesir province

The aim of this study is to determine the presence, virulence factors, and antibiotic susceptibilities of E. coli O157 and L. monocytogenes in ruminant feces and feed. This study was carried out for the first time in Balıkesir province. Feces, pellet feed, and silage samples were analyzed simultaneously for E. coli O157 and L. monocytogenes using feces of one gram and feed of twenty-five grams according to ISO 16654:2001/Amd 1:2017 and ISO 11290-1, respectively. 38 (38%) E. coli O157 strains were isolated and identified from a total of 100 ruminant feces. A total of 3 (3%) E. coli O157:H7 strains were detected by PCR from one hundred ruminant fecal samples. In the study, resistance to antibiotics increased, especially in E. coli O157 isolates. In this study, enterohaemolysin was the predominant virulence factor among the E. coli isolates, and it was thought that it was important for pathogenesis. The Sxt1 gene was higher than the Stx2 gene. A total of 24 L. monocytogenes strains were isolated from a total of 100 ruminant fecal samples and 50 silage samples. Three of these strains were isolated from silage samples taken from the farms, where L. monocytogenes was isolated from sheep feces. As a result, poor quality silage could be an important source of infection for listeriosis in Balıkesir province. Epidemiologically, poor quality silage was thought to be one of the sources of listeriosis. It was thought that ruminant feces played an important role as a reservoir in the spread and transmission of E. coli O157. The antibiotic resistance status of E. coli O157 and L. monocytogenes isolates should be monitored with epidemiological studies.

Molecular detection of Shiga toxin and extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli isolates from sheep and goats.

The Shiga toxin (Stx)-producing Escherichia coli (STEC) have become important global public health concerns. This study investigated the prevalence, antimicrobial resistance profile, and extended-spectrum beta-lactamase-producing E. coli in sheep and goat faeces. A total of 53 E. coli isolates were confirmed by PCR targeting the uidA [β-D glucuronidase] gene. The Shiga toxin genes stx1 and stx2, as well as bfpA, vir, eaeA, lt and aafII virulence genes, were detected in this study. Of the 53 isolates confirmed to be STEC, 100% were positive for stx2 and 47.2% for stx1. Three isolates possessed a combination of stx1 + stx2 + eaeA, while four isolates harboured stx1 + stx2 + vir virulence genes. The isolates displayed phenotypic antimicrobial resistance against erythromycin (66.04%), colistin sulphate (43.4%), chloramphenicol (9.4%) and ciprofloxacin (1.9%). A total of 28.8% of the strains were phenotypically considered ESBL producers and contained the beta-lactamase blaCTX-M-9 and blaCTX-M-25 gene groups. A larger proportion of the E. coli strains (86.8%) contained the antibiotic sulphonamide resistant (sulII) gene, while 62.3%, 62.3%, 52.8%, 43.4%, 41.5%, 20.8%, 18.9%, 11.3%, 11.3%, 9.4%, 9.4% and 5.7% possessed mcr-4, floR, mcr-1, tet(A), sulI, tet(O), tet(W), parC, mcr-2, ampC 5, qnrS and ermB genes, respectively. Thirteen isolates of the ESBL-producing E. coli were considered multi-drug resistant (MDR). One Shiga toxin (stx2) and two beta-lactamase genes (blaCTX-M-9 and blaCTX-M-25 groups) were present in 16 isolates. In conclusion, the E. coli isolates from the small stock in this study contained a large array of high antibiotic resistance and virulence profiles. Our findings highlight the importance of sheep and goats as sources of virulence genes and MDR E. coli. From a public health and veterinary medicine perspective, the characterization of ESBL producers originating from small livestock (sheep and goats) is crucial due to their close contact with humans.

Moving towards on-site detection of Shiga toxin-producing Escherichia coli in ready-to-eat leafy greens

Rapid identification of Shiga toxin-producing Escherichia coli, or STEC, is of utmost importance to assure the innocuousness of the foodstuffs. STEC have been implicated in outbreaks associated with different types of foods however, among them, ready-to-eat (RTE) vegetables are particularly problematic as they are consumed raw, and are rich in compounds that inhibit DNA-based detection methods such as qPCR. In the present study a novel method based on Loop-mediated isothermal amplification (LAMP) to overcome the limitations associated with current molecular methods for the detection of STEC in RTE vegetables targeting stx1 and stx2 genes. In this sense, LAMP demonstrated to be more robust against inhibitory substances in food. In this study, a comprehensive enrichment protocol was combined with four inexpensive DNA extraction protocols. The one based on silica purification enhanced the performance of the method, therefore it was selected for its implementation in the final method. Additionally, three different detection chemistries were compared, namely real-time fluorescence detection, and two end-point colorimetric strategies, one based on the addition of SYBR Green, and the other based on a commercial colorimetric master mix. After optimization, all three chemistries demonstrated suitable for the detection of STEC in spiked RTE salad samples, as it was possible to reach a LOD50 of 0.9, 1.4, and 7.0 CFU/25 g for the real-time, SYBR and CC LAMP assays respectively. All the performance parameters reached values higher than 90 %, when compared to a reference method based on multiplex qPCR. More specifically, the analytical sensitivity was 100, 90.0 and 100 % for real-time, SYBR and CC LAMP respectively, the specificity 100 % for all three assays, and accuracy 100, 96 and 100 %. Finally, a high degree of concordance was also obtained (1, 0.92 and 1 respectively). Considering the current technological advances, the method reported, using any of the three detection strategies, demonstrated suitable for their implementation in decentralized settings, with low equipment resources.

Phylogenetic Analysis of Attaching and Effacing E. coli Strains Isolated From Pet Birds in Iran

Background: Enteropathogenic E. coli (EPEC) and Shiga toxin-producing E. coli (STEC) are categorized as attaching and effacing E. coli (AEEC) due to their eae gene. One of the essential causes of diarrhea in humans is AEEC, which affects birds, too, thereby being considered a zoonotic pathogen. Objectives: Our study aimed to determine AEEC and evaluate its antibiotic resistance and phylogroups. Methods: A total of 200 fecal samples were collected from pet birds referred to the Veterinary Medicine Hospital, University of Tehran. PCR methods were used to detect AEEC using uspA, eae, bfpA, stx1, and stx2 gene-specific primers. The antimicrobial susceptibility of the recovered isolates was determined by the agar disk diffusion and MIC methods. Their phylogroups were analyzed based on Clermont phylotyping methods. Results: Of 200 samples, we isolated 26 (13%) E. coli strains, 9 harbor eae genes. None of the ease-positive samples possessed the bfpA gene, but 4 had stx2, and 5 had stx1 and stx2 genes. Phylogenetic analysis identified the phylogenetic groups of all AEEC isolated strains but 2 (duck and cockatiel). Detected phylogroups include four B2 and three D. Based on our results, 7 out of 9 AEEC isolated strains showed multi-drug resistance. Conclusion: The discovery of common phylogroups of AEEC in pet birds (a common companion animal in Iran with intimate contact with their owners, especially children) and humans, as well as their resistance to a wide range of antibiotics used in human medicine, verifies AEEC as a serious public health threat.

Assessing the Public Health Implications of Virulent and Antibiotic-Resistant Bacteria in Côte d'Ivoire's Ready-to-Eat Salads.

In Côte d'Ivoire, the popularity of ready-to-eat salads has grown substantially. Despite their convenience, these products often face criticism for their microbiological safety. This research was conducted to assess the virulence and antibiotic resistance profiles of Escherichia coli (E. coli), Salmonella spp., and Staphylococcus aureus (S. aureus) isolated from salads available in hypermarkets across Abidjan. The study utilized a combination of microbiological and molecular biology techniques. Results indicated that E. coli isolates harbored virulence genes such as stx2 (50%) and ST (62.50%), though genes stx1 and LT were absent in the samples tested. In S. aureus, virulence genes detected included sea (55.55%), sec (11.110%), and sed (44.44%). The antibiotic resistance assessment revealed high resistance in E. coli to β-lactam antibiotics, with all isolates resistant to cefuroxime (100%) and the majority to ampicillin and cefoxitin (87.5%). Most Salmonella spp. isolates were sensitive to the antibiotics tested, except for cefoxitin and ampicillin, showing resistance rates of 42.85% and 57.15%, respectively. Staphylococcus aureus demonstrated considerable resistance, particularly to cefoxitin (44.44%), benzylpenicillin (100%), and ampicillin (55.55%). In addition, resistance to aminoglycosides (55.55% to both kanamycin and gentamicin) and macrolides (66.66% to erythromycin and 55.55% to clindamycin) was noted. Resistance to various fluoroquinolones ranged between 33.33% and 55.55%. The presence of resistance genes such as blaTEM (10.52%), qnrA (2.26%), qnrB (5.26%), qnrS (5.26%), and mecA (13.15%) in E. coli and S. aureus underscores the challenge of multidrug resistance, exhibiting phenotypes such as ESBL (50%), Meti-R (55.55%), KTG (44.44%), MLSB (44.44%), and FQ-R (25%). These results carry significant epidemiological and public health implications, highlighting the urgent need for improved safety regulations and practices regarding ready-to-eat salads in urban food markets.

Escherichia coli and Salmonella enterica isolated from Egyptian dairy cattle herds: The prevalence and molecular characteristics.

The pathogens Escherichia coli and Salmonella enterica that caused substantial health problems and financial losses were believed to have originated primarily from Egypt's dairy farms. The purpose of this study was to ascertain the occurrence of E. coli and S. enterica in three large dairy farms located in the Egyptian governorate of Sharkia. Furthermore, biochemical and serological characteristics of the isolated isolates were described. Further analysis revealed that several E. coli serovars had the genes stx1, stx2, eaeA, and hylA, while invA, stn, and hilA genes were found in several S. enterica serotypes using a multi-plex PCR. A total of 540 samples of fresh raw cow milk, water, feedstuffs, feces, (108 each), as well as swabs from feeders, milker hands and cattle crushes (36 each ), were gathered and analyzed. The recovery of E. coli from various sampling sources was shown to have an overall prevalence of 62.2% (336/540) in the results. Fecal samples had isolated S. enterica, with a frequency of 0.74% (4/540). The existence of various groups of serovars, such as O26, O44, O55, O78 and O111 for E. coli and Salmonella enteritidis, Salmonella typhimurium and Salmonella inganda for S. enterica was revealed by serological identification of the two species. However, it was discovered that a number of E. coli serovars had much higher percentages of the eaeA and hylA genes as well as shiga-toxin types 1 and 2 (stx1 and stx2). The presence of the invA gene, a diagnostic marker for S. enterica was 100% across all serovars. Salmonella enteritidis possessed both the enterotoxin gene (stn) and the hyper-invasive locus gene (hilA). Salmonella typhimurium had the hilA gene, whereas S. inganda had the stn gene. Escherichia coli and S. enterica recovered in this study have significant genetic risk factors for high pathogenicity and virulence, posing a real threat to dairy population productivity and health, which could spread to the general public through milk.

Molecular identification of the most frequent pathotypes of Escherichia coli in calves with diarrhoea in the Cajamarca region of Peru

Background: Colibacillosis caused by Escherichia coli causes significant economic losses in the livestock sector worldwide and is one of the calves' leading causes of diarrhoea. Aim: This study aimed to identify the most frequent E. coli molecularly pathotypes in calves with diarrhoea in six provinces of the Cajamarca region in the northern highlands of Peru. Methods: Twenty-eight herds of dairy cattle under a semi-intensive rearing system were evaluated; 95 samples were isolated from calves with diarrhoea up to the first month of life, 62 males and 33 females, during the rainy season. Results: The presence of virulence genes of E. coli strains was more prevalent in males; the astA (89.47%), st (83.15%) and f5 (57.89%) genes were more expressed, and the lt (17.89%) and stx2 (1.05%) genes were less expressed. The eae gene (21.05%) was more present in females. Conclusion: When E. coli strains express virulence genes astA, st and f5 and their atypical double, triple and quadruple combination between different observed pathotypes, they give rise to the formation of several pathotypes by the horizontal transfer of virulence genes, which can cause colibacillosis processes in more virulent calves, which is one of the most important causes of diarrhoea in calves in the region of Cajamarca, compromising the sanitary viability in the herds.

Risk Mitigation of E. coli O157 and its Intimin (eaeA) and Shiga Toxin (stx2) Gene Expression in Chilled Chicken Fillets Using Chitosan Nanoparticle Loaded with Lysozyme

Risk Mitigation of E. coli O157 and its Intimin (eaeA) and Shiga Toxin (stx2) Gene Expression in Chilled Chicken Fillets Using Chitosan Nanoparticle Loaded with Lysozyme

Microbiological evaluation of cattle carcasses in some local slaughterhouses at Menoufia governorate

Beef carcass evaluation is generally the basis for judging the commercial value of the livestock and is consequently one of the most common quality control tests carried out in the meat industry. In the current study, sixty swabs were taken from the outer surface of neck and groin (30 of each) of freshly dressed beef carcasses taken from three local slaughterhouses located in El-Bagour, El-May and El-Shohada provinces of Menoufia governorate, Egypt. Swabs were microbiologically examined; the results revealed that groin samples had significantly (P≤0.05) lower contamination levels than that of neck samples. In addition, samples that were collected from El-May’s abattoir revealed the highest bacterial counts, followed by El-Bagour and El-Shohada, respectively. Regarding to detection of some pathogenic bacteria in the examined swab samples, S. aureus was the most detected bacteria, followed by Salmonella spp. and E. coli with total incidence 23.3, 18.3 and 15.0, respectively. However, equal number of S. aureus isolates was obtained from neck and groin samples, groin samples showed higher incidence of Salmonella and E. coli than those of neck samples. In addition, staphylococcal enterotoxins were investigated in the contaminated samples. Results revealed that all of the examined samples had enterotoxin type A only. Moreover, E. coli isolates were serotyped into O103:H2, O146:H21 and O117:H4; out of which, three strains were molecularly examined for their Shiga toxin types 1 (stx-1) and 2 (stx-2) genes; where, stx-1 was detected in 66.7% of the examined strains, while stx-2 was not detected in any of the examined isolates. On the other hand, Salmonella strains were serotyped into S. Enteritidis, S. Montevideo, S. Tsevie, S. Typhimurium and S. Shangani were the detected serotypes. Salmonella Typhimurium was detected in higher incidence than the other detected strains. So, regular monitoring of beef carcasses microbiological evaluation, and application of strict hygienic measures are recommended.

Molecular characterization of common zoonotic protozoan parasites and bacteria causing diarrhea in dairy calves in Ningxia Hui Autonomous Region, China.

Diarrhea caused by zoonotic pathogens is one of the most common diseases in dairy calves, threatening the health of young animals. Humans are also at risk, in particular children. To explore the pathogens causing diarrhea in dairy calves, the present study applied PCR-based sequencing tools to investigate the occurrence and molecular characteristics of three parasites (Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi) and three bacterial pathogens (Escherichia coli, Clostridium perfringens, and Salmonella spp.) in 343 fecal samples of diarrheic dairy calves from five farms in Lingwu County, Ningxia Hui Autonomous Region, China. The total positive rate of these pathogens in diarrheic dairy calves was 91.0% (312/343; 95% CI, 87.9-94.0), with C. perfringens (61.5%, 211/343; 95% CI, 56.3-66.7) being the dominant one. Co-infection with two to five pathogens was found in 67.3% (231/343; 95% CI, 62.4-72.3) of investigated samples. There were significant differences (p<0.05) in the positive rates of Cryptosporidium spp. and diarrheagenic E. coli among farms, age groups, and seasons. Two Cryptosporidium species (C. parvum and C. bovis) and five gp60 subtypes of C. parvum (IIdA15G1, IIdA20G1, IIdA19G1, IIdA14G1, and a novel IIdA13G1) were identified. Two assemblages (assemblage E and zoonotic assemblage A) of G. duodenalis and six ITS genotypes of E. bieneusi (J, Henan-IV, EbpC, I, EbpA, and ESH-01) were observed. Four virulence genes (eaeA, stx1, stx2, and st) of diarrheagenic E. coli and one toxin type (type A) of C. perfringens were detected. Our study enriches our knowledge on the characteristics and zoonotic potential of diarrhea-related pathogens in dairy calves.

Prevalence and antibiogram of shigatoxinproducing E. coli in camel meat and offal.

Camels are important animals in Egypt and other Arab countries on the basis of their economic value and ethnic culture. Escherichia coli is implicated in several gastrointestinal infections and outbreaks worldwide, especially in developing countries. It causes infections that might lead to death. Numerous biological activities, such as antioxidative, antibacterial, anti-diabetic, anti-mutagenic, anti-inflammatory, neuroprotective, and diuretic, are associated with coriander and coriander essential oils. This work targeted investigation of the prevalence, antibiogram, and occurrence of virulence genes of E. coli in camel meat liver and kidney. Besides, the anti-E. coli activity of coriander oil was further examined. Camel meat, liver, and kidneys were collected from local markets in Egypt. Isolation and identification of E. coli were performed. The antimicrobial susceptibility of the obtained E. coli isolates was screened using the disk diffusion assay. To detect the presence of virulence-associated genes (stx1, stx2, eaeA, and hylA gens), polymerase chain reaction was used. An experimental trial was done to investigate the anti-E. coli activity of coriander oil. The obtained results revealed isolation of the following E. coli pathotypes: O17:H18, O128:H2, O119:H6, O103:H4, O145:H-, and O121:H7. The recovered E. coli isolates practiced multidrug resistance profiling with higher resistance toward Erythromycin, Nalidixic Acid, Clindamycin, and Ampicillin. However, the isolates were sensitive to Meropenem and cefoxitin. The recovered isolates had expressed different virulence attributes. Coriander oil of 2% could significantly reduce E. coli O128 count in camel meat by 65%. Therefore, strict hygienic measures are highly recommended during the processing of camel meat. The use of coriander oil during camel meat processing is highly recommended to reduce E. coli count.

Molecular detection of Escherichia coli and Shiga toxin-producing genes stx1 and stx2 from diarrheal samples in dogs

Molecular detection of Escherichia coli and Shiga toxin-producing genes stx1 and stx2 from diarrheal samples in dogs

The Pervasiveness of Bio-Hazards in Street-Vended Dairy Products

A total of 60 diverse dairy product samples, including ice cream, Ras cheese, and Kariesh cheese (20 of each), were randomly collected from street vendors in different regions of Alexandria governorate, Egypt to investigate the prevalence of pathogenic E. coli. The outcomes revealed presumptive positive colonies of 83.33% and 80% in ice cream and Kariesh cheese samples, respectively. Confirmatory tests via conventional biochemical identification affirmed the presence of E. coli in 80% of the samples. However, Vitek 2 compact testing revealed that only 46.66% were positive, in contrast to PCR techniques, which substantiated a prevalence of E. coli in only 25% of the samples, with 35% in street-vended Ras cheese and 25% in Kariesh cheese. The phoA gene, integral to E. coli, was prominently featured in street-vended Ras cheese samples at a striking 100%, while the virulence genes stx1 and stx2 were conspicuously absent, except for sporadic instances of the eaeA gene in street-vended products. These findings uncovered a nuanced landscape of bacterial presence, with E. coli exhibiting a significant prevalence disparity among product sources, particularly with street-vended items showing markedly high contamination rates. It is advised that awareness programs should be established to reduce dairy product contamination among street vendors. Keywords: Dairy; Street-vended; Escherichia coli; Contamination.

First report of the prevalence of Shiga toxinproducing Escherichia coli in ground beef in Quindío, Colombia.

Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen associated with clinical cases of diarrhea in humans. Its main virulence factors are the Shiga toxins (Stx1 and Stx2). Cattle are the main reservoir of STEC, and many outbreaks in humans have been related to the consumption of undercooked ground beef contaminated with this pathogen. To determine the prevalence of STEC in ground beef commercialized in all the butcher shops of a township in the department of Quindío and to characterize the virulence genes of the strains found. Thirty ground beef samples were taken in three different times; stx genes and other STEC virulence factors (eae, ehxA, saa) were detected by multiplex PCR. The overall prevalence of STEC was 33.33 % (10/30 positive samples). We isolated eight non-O157 (LEE-negative) strains with four different genetic profiles: stx2 / stx2-ehxA-saa / stx1-stx2-ehxA-saa / stx1-saa. This is the first report on the prevalence of STEC in ground beef in a township in the department of Quindío.

Toxigenic Escherichia coli with high antibiotic resistance index recovered from sands of recreational beaches of Mumbai, India

Mumbai, India's seven-island city, is known for its sandy beaches as a major tourist attraction, but urbanization and industrialization have weakened the environment. Unregulated sewage disposal and untreated effluents off the coast have made the beach environment vulnerable. Therefore, monitoring water and sand quality at beaches should be mandatory. This study was thus designed to determine the microbiological status of selected sandy beaches, viz. Versova, Juhu, and Girgaon. The study found fecal coliforms in the sand, with stx1 and stx2 genes specific for Shiga toxin-producing E. coli pathotypes in 5.5 % of isolates, whereas the presence of eaeA gene specific for enteropathogenic E. coli pathotype was detected in 12.2 % of isolates, and the presence of the LT and ST genes specific for enterotoxigenic E. coli pathotype was detected in 6.6 % of isolates. Multiple antibiotic-resistant indices indicated high-risk contamination sources. The study suggests routine monitoring of pollution levels at coastal cities' beaches.

Diversity of antimicrobial resistance, stress resistance, and virulence factors of Salmonella, Shiga toxin-producing Escherichia coli, and Listeria monocytogenes from produce, spices, and tree nuts by whole genome sequencing

IntroductionThe objective of this study was to analyze antimicrobial resistance (AMR), stress resistance, and virulence factors through whole genome sequencing (WGS) of 192 isolates comprising 164 Salmonella isolates, 8 non-O157 Shiga toxin-producing Escherichia coli (STEC) isolates, and 20 Listeria monocytogenes isolates.MethodsThese isolates were sourced from a national survey conducted between 2010 and 2017, involving 31,322 samples of produce (31 isolates), nuts (43 isolates), and spices (118 isolates).ResultsThe findings yielded several key insights: (1) Within all Salmonella isolates studied, the most prevalent Salmonella serotypes included Give, Kentucky, Senftenberg, Mbandaka, Anatum, Newport, and Weltevreden. (2) All eight non-O157 STEC isolates were found to carry the genes blaEC, acrF, and mdtM, while all 20 L. monocytogenes isolates possessed fosX and lin genes. The Salmonella isolates displayed diverse AMR gene profiles, with 3.65% exhibiting multi-drug resistance. (3) Both Salmonella and non-O157 STEC isolates were discovered to carry stress genes associated with acid resistance, but none of the L. monocytogenes isolates carried an acid resistance gene. Salmonella isolates were found to carry multiple metal-resistance genes. The non-O157 STEC isolates universally exhibited acid resistance genes, and 4 out of the 20 L. monocytogenes isolates were equipped with resistance genes against biocides. (4) All of the STEC isolates (100%) carried stx1 and stx2 genes, while none of them carried eae and wyz genes. Most L. monocytogenes isolates were found to contain 29 virulence genes and 1 pathogenicity island. All Salmonella isolates carried SPI-9, but lacked SPI-7, SPI-10, SPI-11, SPI-12, mig-5, prefA, tviA, and viaB genes.ConclusionThese findings on AMR, stress resistance, and virulence factors among the investigated isolates highlight the potential risks they pose to public health and provide the scientific foundation for the development of preventative and control strategies and guidance pertaining to these major foodborne pathogens.

Resistance and Virulence Surveillance in Escherichia coli Isolated from Commercial Meat Samples: A One Health Approach.

Escherichia coli is a key indicator of food hygiene, and its monitoring in meat samples points to the potential presence of antimicrobial-resistant strains capable of causing infections in humans, encompassing resistance profiles categorized as serious threats by the Centers for Disease Control and Prevention (CDC), such as Extended-Spectrum Beta-Lactamase (ESBL)-a problem with consequences for animal, human, and environmental health. The objective of the present work was to isolate and characterize ESBL-producing E. coli strains from poultry, pork, and beef meat samples, with a characterization of their virulence and antimicrobial resistance profiles. A total of 450 meat samples (150 chicken, 150 beef, and 150 pork) were obtained from supermarkets and subsequently cultured in medium supplemented with cefotaxime. The isolated colonies were characterized biochemically, followed by antibiogram testing using the disk diffusion technique. Further classification involved biofilm formation and the presence of antimicrobial resistance genes (blaCTX-M, AmpC-type, mcr-1, and fosA3), and virulence genes (eaeA, st, bfpA, lt, stx1, stx2, aggR, iss, ompT, hlyF, iutA, iroN, fyuA, cvaC, and hylA). Statistical analysis was performed via the likelihood-ratio test. In total, 168 strains were obtained, with 73% originating from chicken, 22% from pork, and 17% from beef samples. Notably, strains exhibited greater resistance to tetracycline (51%), ciprofloxacin (46%), and fosfomycin (38%), apart from β-lactams. The detection of antimicrobial resistance in food-isolated strains is noteworthy, underscoring the significance of antimicrobial resistance as a global concern. More than 90% of the strains were biofilm producers, and strains carrying many ExPEC genes were more likely to be biofilm formers (OR 2.42), which increases the problem since the microorganisms have a greater chance of environment persistence and genetic exchange. Regarding molecular characterization, bovine samples showed a higher prevalence of blaCTX-M-1 (OR 6.52), while chicken strains were more likely to carry the fosA3 gene (OR 2.43, CI 1.17-5.05) and presented between 6 to 8 ExPEC genes (OR 2.5, CI 1.33-5.01) compared to other meat samples. Concerning diarrheagenic E. coli genes, two strains harbored eae. It is important to highlight these strains, as they exhibited both biofilm-forming capacities and multidrug resistance (MDR), potentially enabling colonization in diverse environments and causing infections. In conclusion, this study underscores the presence of β-lactamase-producing E. coli strains, mainly in poultry samples, compared to beef and pork samples. Furthermore, all meat sample strains exhibited many virulence-associated extraintestinal genes, with some strains harboring diarrheagenic E. coli (DEC) genes.

Study of the transfer of Shiga toxin-producing Escherichia coli during the slaughter of cattle using molecular typing combined with epidemiologic data

Investigation on the distribution and biological characteristics of Shiga-toxin producing Escherichia coli (STEC) during beef processing is essential for in-plant critical control points and food safety risk assessment. Serogroups and subtypes of stx genes of STEC strains isolated from beef processing lines were first investigated. Identification to cross-contamination among different sampling sites was further conducted by combining multilocus sequence typing (MLST) with the previous distribution and characterization data. The PCR-positive rate for STEC in 435 samples from two slaughter plants in China was 14.3% and the isolation rate for the 62 PCR positive and the entire set of 435 samples were 26% and 3.68% respectively. The existence of serotype O157:H7 (33%) and serogroups O121 (42%) and O26 (21%) as well as the high detection rate of high pathogenic gene stx2a (68%) in these serogroups indicated potential risk to the safety of beef. Traceability analysis showed that hide plays a critical role in cross-contamination between feces, lairage pens and post-washing carcasses from a molecular perspective. Intervening measures revolves around de-hiding should be involved in the in-plant safety control policy according to the tracing analysis.