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This study characterized the effect of distance from beef cattle feedlots, environmental factors, and climate on the occurrence of airborne bacterial indicators and pathogens. Three hundred air samples were collected over 6 months from five feedlots, with each air sample comprising 6000 L of air. Air samples were processed onto TSB-enriched air filters, qPCR-screened, and then qPCR-confirmed for suspect positive colonies of E. coli O157, non-O157-Shiga-toxin-producing E. coli (STEC), Salmonella, and E. coli. Direct enumeration of E. coli was also collected. Although no bacterial pathogens were qPCR-confirmed for the 300 samples, E. coli was detected in 16.7% (50/300) of samples, with an overall mean concentration of 0.17 CFU/6000 L air. Logistic regression analyses revealed a higher odds of E. coli for samples in close proximity compared to >610 m (2000 ft) distance from feedlots, along with significant associations with meteorological factors, sampling hour of day, and the presence of a dust-generating activity such as plowing a field or nearby vehicular traffic. The lack of bacterial pathogen detection suggests airborne deposition from nearby feedlots may not be a significant mechanism of leafy green bacterial pathogen contamination; the result of our study provides data to inform future revisions of produce-safety guidance.

Loop-mediated isothermal amplification, LAMP, is nowadays the most popular isothermal nucleic acid amplification technique, and as such, several commercial, ready-to-use master mixes have flourished. Unfortunately, independent studies to determine their performance are limited. The current study performed an independent evaluation of the existing ready-to-use commercial LAMP master mixes WarmStart® LAMP Kit, LavaLAMP™ DNA Master Mix, Saphir Bst Turbo GreenMaster, OptiGene Fast Master Mix ISO-004, and SynLAMP Mix. To reduce bias, three different genes, namely ttr (Salmonella spp.), rfbE (E. coli O157), and hly (Listeria monocytogenes), were targeted. The comparison was based on amplification speed, performance with decreasing DNA concentrations, and the effect of five typical LAMP reaction additives (betaine, DMSO, pullulan, TMAC, and GuHCl). Significant differences were observed among the different master mixes. OptiGene provided the fastest amplification and showed less detrimental effects associated with the supplements evaluated. Out of the chemicals tested, pullulan provided the best results in terms of amplification speed. It is noteworthy that the different additives impacted the master mixes differently. Overall, the current study provides insights into the performance of commercial LAMP master mixes, which can be of value for the scientific community to better select appropriate reagents when developing new methods. [ABSTRACT FROM AUTHOR]

Foodborne illnesses are frequently caused by Escherichia coli (E. coli). E. coli O157 is regarded as a potentially harmful cause of gastrointestinal disorders associated with consumption of foods with animal origin. Therefore, this study was conducted to determine the presence of E. coli O157:H7 in food outlets in some touristic cities in Egypt. For this purpose, 648 samples including raw chicken meat, cooked chicken meat, raw beef meat, cooked beef meat, food handlers and equipment swabs were collected from 54 food outlets in some touristic cities in Egypt. E. coli O157 was 1.1% (7/648) and 1.2% (5/432) in all examined samples and food samples respectively. Cooked chicken samples were the most contaminated with E. coli O157:H7 with an overall prevalence of 1.9% (2/108). The highest prevalence of E. coli O157:H7 (8.3%) isolates was recovered from raw chicken and cooked beef meat in Hurghada Governorate followed by Luxor Governorate (6.3%). There is no E. coli O157:H7 isolates were identified in Sharm El Sheikh and Aswan governorates. All E. coli O157:H7 isolates (100%) showed resistance to ampicillin (AMP), cefixime, ciprofloxacin and cotrimoxazole. Multidrug resistance (MDR) was observed among all E. coli O157:H7 isolates. All E. coli O157:H7 isolates harbor the eae gene with complete absence of stx1 gene. The most prevalent phylogroup among the E. coli O157:H7 strains was B2 identified in raw and cooked beef and cooked chicken, collected from Luxor, Hurghada, and Alexandria governorates, respectively. Whereas, D phylogenetic group E. coli O157:H7 was only found in raw chicken sample collected from Hurghada Governorate. In conclusion, the detection of pathogenic MDR E. coli O157:H7 in food samples, food handlers and food equipment in some touristic cities in Egypt poses a serious risk to public health. Therefore, it is recommended to focus on identifying practices which increase the risk of food contamination, and on implementing measures to improve the sanitary conditions in the food outlets in touristic cities. [ABSTRACT FROM AUTHOR]

The current study outlines the advancement of an innovative technique for the simultaneous detection of E. coli O157:H7 and its Shiga-like toxins in food samples by utilizing a photonic label-free biosensor coupled with a microfluidic system. This detection method relies on ring resonator transduction that is functionalized with specific bioreceptors against O157:H7 on silicon nitride surfaces capable of binding specifically to the antigen bacterium and its verotoxins. This experiment included the characterization of selected monoclonal and polyclonal antibodies employed as detection probes through ELISA immunoassays exposed to target bacterial antigens. A thorough validation of photonic immunosensor detection was conducted on inoculated minced beef samples using reference standards for E. coli O157:H7 and its verotoxins (VTx1 and VTx2) and compared to gold-standard quantification. The lowest limit-of-detection values of 10 CFU/mL and 1 ppm were achieved for the detection of bacteria and its verotoxins. In this study, the lowest limit of quantification (LoQ) achieved for bacterial quantification was 100 CFU/mL, and, for verotoxins, it was 2 ppm. This study confirmed the effectiveness of a new quality control and food hygiene method, demonstrating the rapid and sensitive detection of E. coli O157:H7 and its verotoxins. This innovative approach has the potential to be applied in food production environments. [ABSTRACT FROM AUTHOR]

Background: Escherichia coli O157 is recognized as a major food-borne pathogen of great concern which can be transmitted by consumption of meat and meat products. Aim: This cross sectional study was conducted to determine the prevalence and antimicrobial resistance of E. coli O157 in mutton meat from butcher shops in Khartoum State, Sudan. Methods: A total of 500 mutton meat carcass swabs were collected in the period March-December 2021 and processed according to ISO16654:2001 methods. Six antibiotics were used to evaluate antimicrobial susceptibility by disc diffusion method according to the guidelines of CLSI. Results: The results showed that the prevalence of E. coli O157 was 1% (5/500) from mutton meat. All isolates were sensitive to amikacin 5 (100%), while all isolates were resistant to ampicillin 5 (100%). For other antimicrobials, the resistance was cotrimoxazole 4 (80%), cefuroxime and cefotaxime 3 (60%). Three out of five isolates (60%) showed multiple drug resistance (MDR). Conclusions: The findings of this study demonstrated that E. coli O157 was present in mutton meat and frequently exhibited multiple drug resistance. Proper manufacturing processes and regular antimicrobial resistance monitoring should be taken into account,

Background: Escherichia coli O157 is recognized as a major food-borne pathogen of great concern which can be transmitted by consumption of meat and meat products. Aim: This cross sectional study was conducted to determine the prevalence and antimicrobial resistance of E. coli O157 in mutton meat from butcher shops in Khartoum State, Sudan. Methods: A total of 500 mutton meat carcass swabs were collected in the period March-December 2021 and processed according to ISO16654:2001 methods. Six antibiotics were used to evaluate antimicrobial susceptibility by disc diffusion method according to the guidelines of CLSI. Results: The results showed that the prevalence of E. coli O157 was 1% (5/500) from mutton meat. All isolates were sensitive to amikacin 5 (100%), while all isolates were resistant to ampicillin 5 (100%). For other antimicrobials, the resistance was cotrimoxazole 4 (80%), cefuroxime and cefotaxime 3 (60%). Three out of five isolates (60%) showed multiple drug resistance (MDR). Conclusions: The findings of this study demonstrated that E. coli O157 was present in mutton meat and frequently exhibited multiple drug resistance. Proper manufacturing processes and regular antimicrobial resistance monitoring should be taken into account. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Over 20% of E. coli O157 illnesses and over 5% of Salmonella illnesses are estimated to be attributable to beef consumption in the United States. Irradiating ground beef is one possible method to reduce disease burden. We simulated the effect of ground beef irradiation on illnesses, hospitalizations, deaths, and direct healthcare costs from ground beef-associated E. coli O157 and Salmonella illnesses in the United States. To estimate the fraction of illnesses, hospitalizations, deaths, and direct healthcare costs preventable by ground beef irradiation, we multiplied the disease burden attributable to ground beef; the estimated percentage of ground beef sold that is not currently irradiated; the percentage of unirradiated ground beef that would be irradiated; and the percentage reduction in risk of illness after irradiation. We multiplied this fraction by estimates of burden and direct healthcare costs to calculate the numbers or amounts averted. Model inputs were obtained from the literature and expert opinion. We used Monte Carlo simulation to incorporate uncertainty in inputs into model estimates. Simulation outcomes were summarized with means and 95% uncertainty intervals (UI). Irradiating 50% of the currently unirradiated ground beef supply would avert 3,285 (95% UI: 624–9,977) E. coli O157 illnesses, 135 (95% UI: 24–397) hospitalizations, 197 (95% UI: 34–631) hemolytic uremic syndrome cases, 2 (95% UI: 0–16) deaths, and $2,972,656 (95% UI: $254,708–$14,496,916) in direct healthcare costs annually. For Salmonella, irradiation would avert 20,308 (95% UI: 9,858–38,903) illnesses, 400 (95% UI: 158–834) hospitalizations, 6 (95% UI: 0–18) deaths, and $7,318,632 (95% UI: $1,436,141–$26,439,493) in direct healthcare costs. Increasing ground beef irradiation could reduce E. coli O157 and Salmonella burden in the United States. Additional studies should assess whether targeted irradiation of higher-risk ground beef products could prevent similar numbers of illnesses with less total product irradiated.

The current study outlines the advancement of an innovative technique for the simultaneous detection of E. coli O157:H7 and its Shiga-like toxins in food samples by utilizing a photonic label-free biosensor coupled with a microfluidic system. This detection method relies on ring resonator transduction that is functionalized with specific bioreceptors against O157:H7 on silicon nitride surfaces capable of binding specifically to the antigen bacterium and its verotoxins. This experiment included the characterization of selected monoclonal and polyclonal antibodies employed as detection probes through ELISA immunoassays exposed to target bacterial antigens. A thorough validation of photonic immunosensor detection was conducted on inoculated minced beef samples using reference standards for E. coli O157:H7 and its verotoxins (VTx1 and VTx2) and compared to gold-standard quantification. The lowest limit-of-detection values of 10 CFU/mL and 1 ppm were achieved for the detection of bacteria and its verotoxins. In this study, the lowest limit of quantification (LoQ) achieved for bacterial quantification was 100 CFU/mL, and, for verotoxins, it was 2 ppm. This study confirmed the effectiveness of a new quality control and food hygiene method, demonstrating the rapid and sensitive detection of E. coli O157:H7 and its verotoxins. This innovative approach has the potential to be applied in food production environments.

Objective: This study was designed to show the effect of adding different levels of microbial (lab-produced) and commercial xanthan (CX) for 30 days on the sensory, chemical, and microbiological parameters of mozzarella cheese (MC). Materials and Methods: The production of xanthan was done in Garcia-Ochoa's medium. The sensory evaluation of the examined MC was achieved through a tabulated scorecard. The Gerber method was used for the determination of MC fat%. The mean counts of staphylococci [colony forming unit (CFU)/gm], coliforms (most probable number/gm), fungi (CFU/gm), and mesophilic bacteria (CFU/gm) were estimated in different fortified cheeses. Also, mean counts of Escherichia coli O157 and Staphylococcus aureus in artificially contaminated MC were determined. Results: The microbial xanthan (MX) had a significant (p < 0.05) effect on the sensory parameters of the examined samples with its concentration (0.0007%) after 20 days of storage. The MX (0.0005%) and CX (0.0002%) had a significant effect on moisture, fat in dry matter, and protein percentage of MC throughout the storage period. The high meltability degree of MC was observed in samples with both types of xanthan (0.0002%) at the end of storage. Conclusion: Both types of xanthan at all concentrations had a significant reducing effect on E. coli O157 and S. aureus in all samples from 10 to 30 days of storage. Xanthan has accepted attentiveness and offers beneficial and safe characteristics that improve its adaptability in MC. In the Middle East, this survival trial of E. coli O157 and S. aureus in the MC supplemented by xanthan is considered a scarce exploratory investigation. [ABSTRACT FROM AUTHOR]

Microbial spoilage is a major cause of food waste. Microbial spoilage is dependent on the contamination of food from the raw materials or from microbial communities residing in food processing facilities, often as bacterial biofilms. However, limited research has been conducted on the persistence of non-pathogenic spoilage communities in food processing facilities, or whether the bacterial communities differ among food commodities and vary with nutrient availability. To address these gaps, this review re-analyzed data from 39 studies from various food facilities processing cheese (n = 8), fresh meat (n = 16), seafood (n = 7), fresh produce (n = 5) and ready-to-eat products (RTE; n = 3). A core surface-associated microbiome was identified across all food commodities, including Pseudomonas, Acinetobacter, Staphylococcus, Psychrobacter, Stenotrophomonas, Serratia and Microbacterium. Commodity-specific communities were additionally present in all food commodities except RTE foods. The nutrient level on food environment surfaces overall tended to impact the composition of the bacterial community, especially when comparing high-nutrient food contact surfaces to floors with an unknown nutrient level. In addition, the compositions of bacterial communities in biofilms residing in high-nutrient surfaces were significantly different from those of low-nutrient surfaces. Collectively, these findings contribute to a better understanding of the microbial ecology of food processing environments, the development of targeted antimicrobial interventions and ultimately the reduction of food waste and food insecurity and the promotion of food sustainability. [ABSTRACT FROM AUTHOR]

Foodborne illnesses are leading source of morbidity and mortality in both developed and developing nations. Escherichia coli O157 is one of the most reported foodborne pathogen that emerged in the past few decades. South East Asia region suffers the highest average burden of diarrhoeal mortality, especially when it comes to child mortality.Query Many studies were undertaken in the developed nations to evaluate the role of E. coli O157 as one of the etiological agent in foodborne outbreaks. In this article, we discuss the distribution of E. coli O157 serotype in the food chains of South East Asian countries, with a special focus on India where more than half a million child diarrhoeal deaths occurs every year and the reasons for which is often not ascertained to the fullest extent. The article also describes in detail about the various detection methods and control measures with respect to E. coli O157. The aim of this study is to document and highlight the extent of Foodborne infections of E. coli O157 origin and thereby taking effective and proactive preventive measures. [ABSTRACT FROM AUTHOR]

The objective of the study was to assess the microbiological safety of popular recreational swimming sites in Central California. Water samples were collected from eleven monitoring sites across the lower reaches of two watersheds for two consecutive swimming seasons (2012-2013), and levels of indicator and pathogenic microorganisms were determined. Data on ambient weather and water chemistry were collected for analyzing their associations with microorganisms in water. All water samples were positive for indicator E. coli with mean concentrations per site ranging from 3.07 to 216.11 MPN/100 ml in 2012 and 13.4 to 226.97 MPN/100 ml in 2013. Mean E. coli concentrations in 27% and 36% samplings sites exceeded the EPA 2012 Recreational Water Quality Criteria recommended mean concentration of ≤ 126 CFU/100 ml of E. coli, in 2012 and 2013, respectively. Cryptosporidium spp. oocysts were detected in all water samples from all sampling sites, with an overall prevalence of 50% and mean concentrations of 0.08 oocysts/l in 2012 and 0.19 oocysts/l in 2013. Giardia spp. cysts were detected at eight sites, with an overall prevalence of 28.8% and mean concentration of 0.2 cysts/l in both years. The majority of the detected Cryptosporidium spp. oocysts and Giardia spp. cysts appeared damaged under microscopy. E. coli O157:H7 was detected in 9% of water samples, with positive samples limited to three sites. Salmonella spp. were detected in all but one site across the two years, with mean concentrations of 0.94 MPN/l in 2012 and 1.85 MPN/l in 2013. Cryptosporidium spp. oocyst concentrations were negatively associated with 30-day mean wind speed and cumulative precipitation and dissolved oxygen in water. Giardia spp. cyst concentrations were positively associated with turbidity and pH of water and negatively associated with E. coli concentrations and 24-h mean air temperature. Salmonella spp. concentrations were positively associated with 30-day mean air temperature. The occurrence of E. coli O157:H7 was positively associated with previous 30-day cumulative precipitation.

Shiga toxin producing Escherichia coli (STEC) serotypes are recognized as potentially important food-borne pathogens for humans. Ingestion of E. coli contaminated food is largely known to originate from livestock. Cattle and sheep herds hold the majority of agricultural revenue in Türkiye but Anatolian water buffaloes have often been underestimated for foodborne pathogens. The aim of this study is to determine virulence genes harboring E. coli O157 and six major non-O157 STEC (O26, O45, O103, O111, O121, and O145) serotypes in feces of healthy Anatolian water buffaloes by using multiplex PCR (mPCR) method. Of the collected 458 fecal samples from healthy live animals, we have performed virulence and serotype targeting mPCR following direct DNA extraction from collected samples. Results indicate that there is 0.9% of O157 prevalence while six major non-O157 E. coli have not been identified. The characterization results of the virulence genes also showed that eae is most prevalent (5.7%) followed by ehxA (3.9%) and stx1 (3.1%). In this study, we have shown Anatolian buffaloes might have a relationship with other O-type E. coli strains. Non-O157 STECs, which are often disregarded in both animals and humans, should be investigated. As a consequence, gaining regional or national data collection will allow to implement better effective diagnosis and treatment options. [ABSTRACT FROM AUTHOR]

Escherichia coli serogroup O157 is the main causative agent of several intestinal and extra‐intestinal foodborne diseases in humans through consumption of low‐dose contaminated foods such as milk, beef, and vegetables. To date, studies regarding the quantitative prevalence of E. coli O157 in foods are so limited. Therefore, this study aimed to evaluate the quantitative prevalence rate of E. coli serogroup O157 in raw milk (n = 144), vegetable salad (n = 174), and minced beef samples (n = 108) using the real‐time qPCR SYBR green melting curve method targeting the rfbA gene. First, we evaluated the method and found a sensitive and specific qPCR assay with 1 log of CFU/ml detection limit to detect E. coli O157 (Tm = 80.3 ± 0.1°C). About 2.77%, 10.18%, and 9.19% of raw milk, minced beef, and vegetable salad samples, respectively, were contaminated with E. coli O157. Minced beef and vegetable salad samples were significantly more contaminated than raw milk samples. Population average of E. coli O157 in raw milk, minced beef, and vegetable salad samples were 2.22 ± 0.57, 3.30 ± 0.40, and 1.65 ± 0.44 log CFU/ml or gr, respectively. Significantly higher levels of population of E. coli O157 were observed in minced beef samples. Minced beef can be regarded as the main food in the transmission of this foodborne pathogen. Routine quantitative rapid monitoring is strongly suggested to be carried out to prevent foodborne diseases caused by E. coli O157. [ABSTRACT FROM AUTHOR]

Microbial biofilms on environmental plastic pollution can serve as a reservoir for both pathogenic and commensal bacteria. Associating with this 'plastisphere', provides a mechanism for the wider dissemination of pathogens within the environment and a greater potential for human exposure. For pathogens to bind to environmental plastic waste they need to be in close contact with it; therefore, understanding how rapidly pathogens can bind to plastics and the temporal colonisation dynamics of the continual cycling between the plastisphere and the environment are important factors for quantifying the persistence of human pathogens. Using simulated environmental conditions, we demonstrate that pathogenic E. coli O157 can rapidly colonise plastics (within 30 min) and persist for extended periods (at least 21 days), at concentrations sufficient to cause human infection. Importantly, repeated colonisation and dissociation cycles of E. coli O157 from the plastisphere leads to an enhanced capacity for persistence and the emergence of variants with increased virulence traits, including improved biofilm formation and antibiotic tolerance. This phenotypic adaptation to repeated colonisation of environmental plastic surfaces could be selecting for more persistent and virulent strains of pathogens, and hence increase the co-pollutant risks associated with plastic pollution. [Display omitted] • Plastic can be rapidly colonised with potentially pathogenic bacteria. • Pathogenic bacteria become adapted to the plastisphere following repeated exposure. • Plastisphere adaptation can result in concomitant increases in biofilm formation and antibiotic tolerance. • The co-pollutant risk of plastics and pathogens poses a heightened human health risk. [ABSTRACT FROM AUTHOR]

This study aimed to develop novel primer-probe sets specifically optimized for detecting E. coli and E. coli O157 through comparative genomic analysis. Genomic data from 2396 E. coli strains, including 228 strains of E. coli O157, were retrieved from the National Center for Biotechnology Information (NCBI). From the analysis, yegR and GDP-mannose mannosyl hydrolase (GDPMH) genes were selected as primer targets for E. coli and E. coli O157:H7, respectively. The sensitivity and specificity of the designed primer-probe sets were evaluated in 48 E. coli strains (including 30 E. coli O157) and 17 non- E. coli strains, totaling 65 strains, and the results indicated high sensitivity and specificity. Tryptic soy broth (TSB), carrots, chicken, milk, potatoes, apple juice, and orange juice did not significantly interfere with detecting E. coli and E. coli O157; however, 50% potato samples did. The efficacy of the designed primers was compared among ground pork, lettuce, and potato samples. Reduced detection efficiency was noted in the lettuce and potato samples. Wavelength interference with components of the lettuce homogenate may have reduced detection efficiency. For potato samples, the high affinity of chlorogenic acid, a compound found in potatoes, for Taq DNA polymerase, a component of the mastermix, contributed to the reduced detection efficiency. The primer and probe sets described in this study, coupled with an understanding of possible interference from food components, will aid in detecting E. coli O157 in the food industry. [ABSTRACT FROM AUTHOR]

Escherichia coli O157 (E. coli O157) is responsible for outbreaks of high morbidity in food-borne infections. The development of sensitive, reliable, and selective detection systems is of great importance in food safety. In this work, two high fundamental frequency (HFF) piezoelectric genosensors (100 and 150 MHz) were designed and validated for the rfbE gene detection, which encodes O-antigen in E. coli O157. HFF resonators offer improved sensitivity, small sample volumes, and the possibility of integration into lab-on-a-chip devices, but their sensing capabilities have not yet been fully explored. This HFF-QCM genosensor uses the method of physisorption based on the union between the streptavidin and the biotin to immobilize the genetic bioreceptor on the surface and detect its hybridization with the target sequence. Parameters such as molecular coating, specificity, and variability were tested to enhance its performance. Although both genosensors evaluated are able to determine the target, the 100 MHz device has a higher response to the analyte than the 150 MHz platform. This is the first step in the development of an HFF-QCM genosensor that may be used as a trial test of E. coli O157 in large batches of samples. [ABSTRACT FROM AUTHOR]

Hemolytic uremic syndrome (HUS) is a systemic sequelae from gastrointestinal infection with Shiga toxin (Stx) producing Escherichia coli (STEC) that can result in acute kidney injury, lasting renal disease, and death. Despite a window for intervention between hemorrhagic diarrhea and onset of HUS, no specific therapies exist to prevent or treat HUS following STEC infection. Furthermore, there is no way to predict which patients with STEC will develop HUS or any rapid way to determine which Stx variant is present. To address this, we have broadened the therpay to neutralize additional toxin variants. It contains a multimer of nanobodies derived from camelid heavy chain antibody fragments (VHHs). An improved V HH-based n eutralizing a gent (VNA2) is delivered intramuscularly as RNA combined with LION nanoparticles rather than mRNA, that replicates on administration (repRNA), resulting in a rapidly circulating VNA that can bind systemic toxin. The RNA/VNA2-Stx administered intramuscularly prevents toxicity and death in a mouse model of acute Stx toxicity., Competing Interests: The authors declare no conflict of interest.

Free-living amoebae (FLA) are widely distributed protozoa in nature, known to cause severe eye infections and central nervous system disorders. There is growing attention to the potential role that these protozoa could act as reservoirs of pathogenic bacteria and, consequently, to the possibility that, the persistence and spread of the latter may be facilitated, by exploiting internalization into amoebae. Shiga toxin-producing strains of Escherichia coli (STEC) are zoonotic agents capable of causing serious diseases, such as hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). Cattle represent the main natural reservoir of STEC, which are frequently found also in other domestic and wild ruminants, often without causing any evident symptoms of disease. The aspects related to the ecology of STEC strains in animal reservoirs and the environment are poorly known, including the persistence of these microorganisms within niches unfavorable to survival, such as soils or waters. In this study we investigated the interaction between STEC strains of serotype O157: H7 with different virulence gene profiles, and a genus of a wild free-living amoeba, Acanthamoeba sp. Our results confirm the ability of STEC strains to survive up to 20 days within a wild Acanthamoeba sp., in a quiescent state persisting in a non-cultivable form, until they reactivate following some stimulus of an unknown nature. Furthermore, our findings show that during their internalization, the E. coli O157 kept the set of the main virulence genes intact, preserving their pathogenetic potential. These observations suggest that the internalization in free-living amoebae may represent a means for STEC to resist in environments with non-permissive growth conditions. Moreover, by staying within the protozoa, STEC could escape their detection in the vehicles of infections and resist to the treatments used for the disinfection of the livestock environment. [ABSTRACT FROM AUTHOR]

Bacterial contamination of fermented dairy products has serious implications for both safeties of the final products, and the transmission of foodborne pathogens to the consumers. In this regard, 175 samples of fermented dairy products including 50 each of plain yoghurt, fruit yoghurt, laban rayeb, and 25 from mish cheese were randomly collected from different supermarkets and retail shops in Dakahlia Governorate, Egypt. Samples were examined bacteriologically for the prevalence of Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), particularly, E. coli O157. The recovered isolates were examined for the detection of toxin, and virulence-associated genes using PCR. The obtained results showed that the average counts (CFU/g) of total bacterial, psychrotrophic, coliform, and S. aureus were 1.72x105, 9.9 x103, 5.08x102, and 3.07 x102 for the plain yoghurt, 7.1 x 104, 2.3 x 103, 9.5 x10, and 3.3 x10 for fruit yoghurt, 6.07x104, 6.1 x 103, 9.8 x10, and 1.35x102 for laban rayeb, and 1.2 x 106, 2.5 x104, 8.3 x10, and 7.2 x103 for Mish cheese, respectively. E. coli and E. coli O157 were detected in 13 out of 175 (7.43%) and 4 out of 175 (2.3%) samples, respectively. Using PCR for 9 selected E. coli isolates showed that 7 out of 9 E. coli isolates were positive for the stx1 gene, 5 out of 9 were positive for stx2, and 3 out of 9 were positive for eaeA, and 4 out of 9 were positive for hylA. S. aureus showed that 55.6% of the recovered isolates were coagulase positive. Ten randomly selected S. aureus isolates tested positive for nuc (thermonuclease genes), while mecA (methicillin-resistant S. aureus "MRSA") gene was detected in 20% of the examined isolates. Therefore, strict hygienic measures should be adopted during all steps of the manufacture of such dairy products. [ABSTRACT FROM AUTHOR]

This study was planned to determine sources of contamination of E. coli O157 that are mainly discovered in animal, children's feces, milk, and water samples and serve as reservoirs for contamination by E. coli O157. About 500 samples (40 cattle fecal swabs, 150 sheep fecal swabs, 120 children fecal swabs, 100 milk samples, and 90 drinking water) were collected for bacteriological examination and identified by the Vitek2 system beside molecular detection of 16 isolates of E.coli O157 by PCR as well as detection of virulence genes (stx1, stx2, and eae) for STEC and EPEC isolates. Out of 500 examined samples 222 (44.4%) were positive for E. coli, by the Vitek2 system 16 (7.2%) isolates were positive for E. coli O157 (7.2%) with high incidence in cattle samples (20%), water samples (12.5%), children fecal samples (12.5% & 10%) but low percent (7.9%) in raw milk and (1%) in sheep. Molecular identification of 16 isolates of E. coli O157 by PCR detected 9 stx1, 6 stx2, and 16 positive - eae strains. It could be concluded that its important to put a control strategic plan for contamination by E. coli O157 on farms and hospitals to minimize the incidence of different infections in animals and humans. [ABSTRACT FROM AUTHOR]

Escherichia coli O157 (E. coli O157) is one of the most dangerous foodborne pathogens worldwide. A convenient, sensitive, and specific method for the E. coli O157 detection is necessary. The present study developed an isothermal real-time recombinase polymerase amplification (real-time RPA) assay and an RPA combined with lateral flow strip (LFS-RPA) to detect E. coli O157 targeting the conserved region of the rfbE gene. Results of this study demonstrated that the real-time RPA was successfully conducted at the constant temperature of 39 °C for 20 min. Furthermore, the LFS-RPA was performed in an incubator block at 39 °C for 15 min, with the products visible with the naked eye within 5 min. It was found that the two RPA assays were highly specific to E. coli O157 and there were no cross-reactions with other microorganisms tested. The detection limit of E. coli O157 DNA or pure culture using LFS-RPA was 3.5 × 102 fg/μL and/or 1.0 × 102 CFU/mL, respectively, which was 10 times higher than that of real-time PCR and real-time RPA. Moreover, the practicality of the way to discover E. coli O157 was validated with artificial contamination assay. Positive results were obtained within 6–15 min in the real-time RPA and within 15 min in the LFS-RPA, while it took approximately between 28 and 45 min in the real-time PCR. Furthermore, these assays require no sophisticated instruments, specialized technicians, and strict laboratory conditions. All of these helps to manifest that the developed RPA assays were simple, highly specific, sensitive, and rapid, and they could be employed in resource-constrained areas. [ABSTRACT FROM AUTHOR]

Abstract Background Gastroenteritis is a common infectious disease in children, which results in high mortality and morbidity, especially in resource-poor countries. This study presents the selected main gastroenteritis causing bacteria, including Escherichia coli O157, Salmonella and Shigella species delineating their prevalence and resistance pattern to the clinically used antibiotics. Results A total of 346 stool specimens from children of clinically suspected gastroenteritis below five years have been obtained, and bacterial pathogens were recovered using selective media, biochemical and serologic tests. We found that 35 (10%) of them were confirmed bacterial gastroenteritis (BGE) with either Escherichia coli O157 (14%), Salmonella spp. (43%), and Shigella spp. (43%). Nevertheless, the prevalence of E. coli O157, Salmonella spp., and Shigella spp. in this study were documented as 1.45%, 4.34%, and 4.34%, respectively. Moreover, 2 (40%) of E. coli O157, 4 (26.67%) of Salmonella spp., and 14 (93%) of the Shigella spp. were found as multidrug-resistant. Nonetheless, Shigella spp. isolates showed 100%, 87%, and 73% resistance to cotrimoxazole, ciprofloxacin, and azithromycin respectively, while E. coli O157 showed 80% resistance to cotrimoxazole and 60% to ciprofloxacin and azithromycin. On the contrary, cotrimoxazole, ciprofloxacin, azithromycin, and tetracycline were resistant in 40%, 47%, 27%, and 53% of Salmonella spp. isolates respectively. Conclusion These findings generate significant insights on the prevalence and antibiotic resistance of the three major gastroenteritis causing bacteria in the study area. Therefore, it will help physicians and policymakers selecting the right antibiotics in essential cases, particularly, reevaluation of recommending cotrimoxazole, ciprofloxacin, and azithromycin in the management of bacterial gastroenteritis.

Free-living amoebae (FLA) are widely distributed protozoa in nature, known to cause severe eye infections and central nervous system disorders. There is growing attention to the potential role that these protozoa could act as reservoirs of pathogenic bacteria and, consequently, to the possibility that, the persistence and spread of the latter may be facilitated, by exploiting internalization into amoebae. Shiga toxin-producing strains of Escherichia coli (STEC) are zoonotic agents capable of causing serious diseases, such as hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). Cattle represent the main natural reservoir of STEC, which are frequently found also in other domestic and wild ruminants, often without causing any evident symptoms of disease. The aspects related to the ecology of STEC strains in animal reservoirs and the environment are poorly known, including the persistence of these microorganisms within niches unfavorable to survival, such as soils or waters. In this study we investigated the interaction between STEC strains of serotype O157: H7 with different virulence gene profiles, and a genus of a wild free-living amoeba, Acanthamoeba sp. Our results confirm the ability of STEC strains to survive up to 20 days within a wild Acanthamoeba sp., in a quiescent state persisting in a non-cultivable form, until they reactivate following some stimulus of an unknown nature. Furthermore, our findings show that during their internalization, the E. coli O157 kept the set of the main virulence genes intact, preserving their pathogenetic potential. These observations suggest that the internalization in free-living amoebae may represent a means for STEC to resist in environments with non-permissive growth conditions. Moreover, by staying within the protozoa, STEC could escape their detection in the vehicles of infections and resist to the treatments used for the disinfection of the livestock environment.

Microbial spoilage is a major cause of food waste. Microbial spoilage is dependent on the contamination of food from the raw materials or from microbial communities residing in food processing facilities, often as bacterial biofilms. However, limited research has been conducted on the persistence of non-pathogenic spoilage communities in food processing facilities, or whether the bacterial communities differ among food commodities and vary with nutrient availability. To address these gaps, this review re-analyzed data from 39 studies from various food facilities processing cheese (n = 8), fresh meat (n = 16), seafood (n = 7), fresh produce (n = 5) and ready-to-eat products (RTE; n = 3). A core surface-associated microbiome was identified across all food commodities, including Pseudomonas, Acinetobacter, Staphylococcus, Psychrobacter, Stenotrophomonas, Serratia and Microbacterium. Commodity-specific communities were additionally present in all food commodities except RTE foods. The nutrient level on food environment surfaces overall tended to impact the composition of the bacterial community, especially when comparing high-nutrient food contact surfaces to floors with an unknown nutrient level. In addition, the compositions of bacterial communities in biofilms residing in high-nutrient surfaces were significantly different from those of low-nutrient surfaces. Collectively, these findings contribute to a better understanding of the microbial ecology of food processing environments, the development of targeted antimicrobial interventions and ultimately the reduction of food waste and food insecurity and the promotion of food sustainability.

Korean style kimchi contaminated with Shiga toxin-producing Escherichia coli (STEC) O157:H7 was the cause of an outbreak in Canada from December 2021 to January 2022. To determine if this STEC O157:H7 has greater potential for survival in kimchi than other STEC, the outbreak strain and six other STEC strains (O26:H11, O91:H21, O103:H2, O121:H19, and two O157:H7) were inoculated individually at 6 to 6.5 log CFU/g into commercially sourced kimchi and incubation at 4 °C. At intervals of seven days inoculated and control kimchi was plated onto MacConkey agar to enumerate lactose utilising bacteria. The colony counts were interpreted as enumerating the inoculated STEC, since no colonies were observed on MacConkey agar plated with uninoculated kimchi. Over eight weeks of incubation the pH was stable at 4.10 to 4.05 and the STEC strains declined by 0.7–1.0 log, with a median reduction of 0.9 log. The linear rate of reduction of kimchi outbreak STEC O157:H7 was −0.4 log per 30 days (Slope Uncertainty 0.05), which was not significantly different from the other O157 and nonO157 STEC strains (P = 0.091). These results indicate that the outbreak was not due to the presence of strain better adapted to survival in kimchi than other STEC, and that STEC can persist in refrigerated Korean style kimchi with a minimal decline over the shelf-life of the product. • An outbreak of Shiga toxin-producing Escherichia coli O157:H7 involved kimchi. • Survival of outbreak STEC O157 in kimchi compared to other O157 and non-O157 STEC. • STEC O157 and non-O157 STEC reduced by 0.7–1.0 log over 8 weeks at 4 °C. • There was no difference in survival between outbreak STEC O157 and the other STEC. [ABSTRACT FROM AUTHOR]

This study was conducted on canine puppies (n=600) with diarrhoea during October 2019-20 in district Lahore, Pakistan to know the molecular prevalence of E. coli O157:H7, its associated risk factors and the impact of bacterial diarrhea on various blood parameters and serum electrolytes. PCR-based positive (n=21) and negative (n=21) cases were sampled for their blood, and serum for the haemato-serum electrolyte analysis. The results showed that the overall prevalence of E. coli O157:H7 was 3.5% (P<0.05) in canine diarrheic pups. The highest prevalence of E. coli O157:H7 was found within the UVAS pet center (10 %, 10/100). Season, food, drinking water plus animal breed, sex, co-habitation with other animals and contact with animals' feces, were significantly (P<0.05) associated with the E. coli O157:H7 prevalence. Mean value of Hb (P<0.01), RBCs (P<0.05), lymphocytes (P<0.01) and platelets (P<0.05) were reduced significantly, while neutrophils, PCV and TLC were increased significantly(P<0.01) in the infected group as compared to the control healthy group. A significant decrease was found in sodium mEq/l (P<0.01) and potassium mEq/l (P<0.05), while a significant (P<0.01) increase was found in chloride mEq/l and bicarbonate mmol/l in the infected group as compared to control healthy group. In conclusion, the E. coli O157:H7 was present in the canine puppies of district Lahore Pakistan and had a high effect on blood parameters and serum electrolytes. [ABSTRACT FROM AUTHOR]

The main objective of this study is to determine the PCR quantification levels required for detecting enterohemorrhagic Escherichia coli O157 by examining its most virulent genes: stx1, stx2, and rfbE. The PCR’s sensitivity results show a detection limit between 0,011 ng µL-1 of DNA and 0,033 ng µL-1 of DNA for stx1 and stx2 and of 0,0037 ng µL-1 DNA for rfbE. The lowest cut-off limit ranged between 0,033 ng µL-1 of DNA and 0,099 ng µL-1 of DNA for stx1 and stx2, while for rfbE it is 0,033 ng μL-1 of DNA. The selectivity (inclusivity and exclusivity) and the robustness are 100% for the three genes examined, showing the PCR’s reproducibility for distinguishing E. coli O157 from the other serotypes. It is concluded that conventional PCR is a technique that allows monitoring the presence of E. coli O157 by targeting its most virulent genes (stx1, stx2, and rfbE). [ABSTRACT FROM AUTHOR]

Background: Escherichia coli O157:H7 is one of foodborne pathogenic bacteria that causes serious infections in people around the world. Cattle are a barrage of E. coli O157:H7, fresh products contaminated with cattle feces are the common sources for the pathogen. E. coli O157:H7 has the ability to survive well in the environment. Two main virulence factor genes of E. coli O157 have been detected in this study, which are responsible to produce shiga toxin and increase the pathogenicity of this bacterium. Objective: To find out the rate of fresh food contamination by E. coli, and detect the genes responsible for shiga toxin production and increase the pathogenicity of E. coli among isolates from salad samples. Patients and Methods: Two hundred salad and vegetable samples were collected from different restaurants and small shops in Erbil city from April - September (2019). Samples were cultured on eosin methylene blue (EMB) agar plates; typical E. coli with a metallic shine appeared. Polymerase chain reaction technique was used for detecting (uidA, rfbo157 and stx1, stx2) genes. Results: Overall, 32% (64/200) of salad samples were contaminated by E. coli as identified by culturing on EMB agar. Then isolated E. coli was confirmed by detecting the presence of uidA gene and the rate was 88% (56/64). Pathogenicity and toxin production detection was done for all confirmed E. coli isolates, by detecting the presence of rfbo157 gene (479 bp), among 56 isolates only (4) isolates was positive for rfbo157 gene, and (7) isolates showed positive result for shiga toxin. Conclusion: This study focuses on the serotype E. coli O157:H7, a high percentage of E. coli was detected in salad samples which indicated the fecal contamination. The presence of rfbo157 gene and stx1, stx2 are the indications for pathogenicity and shiga toxin production respectively. [ABSTRACT FROM AUTHOR]

The current study was conducted to analyze the protective effect of rosemary leaves extract on renal defect experimentally induced by infecting with E. coli O157. Sixty male mice were divided into 6 groups as follow: C-(control negative), C+ (infected with E.coli O157 without treatment), T1(Immunomodiolater group), T2 (infected with E. coli 0157 then treated with Rosemary Alcoholic extract at 0.5ml/20mg B.W. orally, T3 (infected with E coli 0157 then treated with meropenem 90 mg/kg.bw only and T4 (Infected with E.coli 0157 then treated with meropenem and Rosemary Alcoholic extract). The result showed significant decrease (P £ 0.05) in serum creatinine in groups treated with plant extract alone when administered as protective and as immunomodulatory. Furthermore, there were maximum depletion of serum urea levels which were significant (P £ 0.05) in the group treated with plant as treatment and also in the group treated with combination of plant extract with meropenem drug. Groups treated with meropenem and those treated with Rosemary extract alone (before infection), showed significant depletion in urea level in comparison to control +ve. Histopathological slides revealed vascular degeneration of most cortical renal tubules in kidney of animals (C+ group). While T1 group showed the presence of nephrosis associated with dilation of collecting tubules. In addition there were mild cloudy swelling of cortical renal tubules in animals of T2 group. Finally normal appearance of renal cortex was noticed in kidneys of T3 group. In conclusion, the present results provide a clear experimental evidence for the promising role of Rosmarinus officinalis leaves extract in the protection against E.coli O157. [ABSTRACT FROM AUTHOR]

Objectives: E. coli O157 is considered as one of the important pathogens causing subclinical mastitis in dairy cows. This study was undertaken to isolate E. coli O157 from the milk samples collected from subclinical mastitic cows using polymerase chain reaction (PCR) and investigate their antibiotic sensitivity patterns. Materials and Methods: 50 California Mastitis Test (CMT) positive milk samples were collected from apparently healthy crossbreed dairy cows in Baghabari, Sirajganj. For the enrichment and isolation of the organism, nutrient broth, MacConkey agar, and EMB agar were used. Later on, observing the biochemical tests result, all the isolates of E. coli were confirmed by PCR using genus-specific 16SrRNA primers. PCR-positive samples were then screened for the presence of the rfbO157 gene using gene-specific primers. The antibiotic sensitivity pattern of E. coli was assessed by the disk diffusion method against seven commonly used antibiotics. Results: Altogether, 8 (16%) isolates of E. coli were obtained, among which 5 (10%) were rfbO157 PCR positive. From the antibiotic sensitivity test, Gentamicin was the highest (75%) sensitive to the isolates, followed by Levofloxacin (62.5%), Cefixime (50%), Tetracycline (50%), and Ceftriaxone (25%). The highest resistance pattern was found against Ampicillin (100%) and Amoxycillin (87.5%). Conclusion: Raw milk containing E. coli O157 does not only reflect the status of the dairy herd. Additionally, it poses a serious threat to human health if it is consumed raw or used to make any type of value-added food product. [Vet. Res. Notes 2021; 1(2.000): 6-11]

Abstract Background Enterohemorrhagic Escherichia coli O157:H7 (EHEC) is a significant foodborne pathogen that resides asymptomatically within cattle and other ruminants. The EHEC genome harbors an extensive collection of mobile genetic elements (MGE), including multiple prophage, prophage-like elements, plasmids, and insertion sequence (IS) elements. Results A chronological collection of EHEC strains (FRIK804, FRIK1275, and FRIK1625) isolated from a Wisconsin dairy farm (farm X) comprised a closely related clade genetically differentiated by structural alterations to the chromosome. Comparison of the FRIK804 genome with a reference EHEC strain Sakai found a unique prophage like element (PLE, indel 1) and an inversion (1.15 Mb) situated symmetrically with respect to the terminus region. Detailed analysis determined the inversion was due to homologous recombination between repeat sequences in prophage. The three farm X strains were distinguished by the presence or absence of indel 3 (61 kbp) and indel 4 (48 kbp); FRIK804 contained both of these regions, FRIK1275 lacked indel 4, and indels 3 and 4 were both absent in FRIK1625. Indel 3 was the stx2 prophage and indel 4 involved a deletion between two adjacent prophage with shared repeat sequences. Both FRIK804 and FRIK1275 produced functional phage while FRIK1625 did not, which is consistent with indel 3. Due to their involvement in recombination events, direct and inverted repeat sequences were identified, and their locations mapped to the chromosome. FRIK804 had a greater number and overall length of repeat sequences than E. coli K12 strain MG1655. Repeat sequences were most commonly associated with MGE. Conclusions This research demonstrated that three EHEC strains from a Wisconsin dairy farm were closely related and distinguished by variability within prophage regions and other MGE. Chromosome alterations were associated with recombination events between repeat sequences. An inventory of direct and inverted repeat sequences found a greater abundance and total length of repeat sequences in the EHEC strains compared to E. coli strain MG1655. The locations of the repeat sequences were biased towards MGE. The findings from this study expand our understanding of the precise molecular events and elements that contributed to genetic diversification of wild-type EHEC in the bovine and farm environments.

This study characterized the effect of distance from beef cattle feedlots, environmental factors, and climate on the occurrence of airborne bacterial indicators and pathogens. Three hundred air samples were collected over 6 months from five feedlots, with each air sample comprising 6000 L of air. Air samples were processed onto TSB-enriched air filters, qPCR-screened, and then qPCR-confirmed for suspect positive colonies of E. coli O157, non-O157-Shiga-toxin-producing E. coli (STEC), Salmonella, and E. coli. Direct enumeration of E. coli was also collected. Although no bacterial pathogens were qPCR-confirmed for the 300 samples, E. coli was detected in 16.7% (50/300) of samples, with an overall mean concentration of 0.17 CFU/6000 L air. Logistic regression analyses revealed a higher odds of E. coli for samples in close proximity compared to >610 m (2000 ft) distance from feedlots, along with significant associations with meteorological factors, sampling hour of day, and the presence of a dust-generating activity such as plowing a field or nearby vehicular traffic. The lack of bacterial pathogen detection suggests airborne deposition from nearby feedlots may not be a significant mechanism of leafy green bacterial pathogen contamination; the result of our study provides data to inform future revisions of produce-safety guidance.

Objective: In this study we aimed to determine bacterial causes of diarrhea in patients presenting to the pediatric clinic. Methods: The stool specimens of 487 patients with diarrhea from pediatric emergency and other pediatric clinics were investigated in order to determine gastroenteritis causes. Microscopic examinations, and appropriate culture methods were performed to determine Salmonella, Shigella, E. coli O157: H7, Campylobacter, Yersinia enterocolitica, Vibrio cholerae, and Aeromonas species. Stool specimens of patients with diarrhea were stained with methylene blue for microscopic examination, and they were cultured on propagating selenite F medium for Salmonella spp. and Shigellas spp., and 8 h later, were subcultured to Salmonella Shigella agar. Also they were cultured to hektoen and xylose lysine desoxycholate agar, to Sorbitol MacConkey agar for E. coli O157: H7 strain, to MacConkey agar for Yersinia enterocolitica, to Campylobacter selective agar for Campylobacter spp., to vibrio selective agar for Vibrio cholerae and to 5% sheep blood agar for Aeromonas spp.. The isolated microorganisms were identified by conventional methods, biochemical tests, specific antibody/antigens and VITEK® 2 (bioMérieux, Marcy l'Etoile, France) device. Results: Salmonella spp. was the most frequently isolated bacteria that was isolated in 19 (3.9%) samples, and Campylobacter spp. was isolated in seven (1.4%), and E. coli O157:H7 and Aeromonas spp. were isolated in three (0.6%) samples. We observed that Salmonella isolation was highest in HE agar. It is remarkable that E. coli O157: H7 was observed among the bacterial agents of gastroenteritis in children. Conclusions: We concluded that E. coli O157: H7 strain should be investigated especially in stool samples with bloody diarrhea in our region, and bacteria such as Campylobacter spp. Aeromonas spp. should be investigated in addition to Salmonella spp. for investigation of gastroenteritis agents in children. [ABSTRACT FROM AUTHOR]

Background: Shiga toxin-producing Escherichia coli (STEC) infection is the most common cause of hemolytic uremic syndrome (HUS). Only few studies correlated serotypes and stx genotypes with disease severity. This study aimed to update STEC serotypes, stx genotypes, and virulence factors (eae and ehxA) in a cohort of patients with STEC-HUS and investigate whether they influence the severity of disease. Methods: In this multicentric study, children hospitalized between 2005 and 2016 with STEC-HUS confirmed by the National Reference Laboratory were included. Serotypes (O157, O145, O121, and others), stx genotypes (stx1a, stx2a, stx2c,stx2d, and others), and virulence factors were analyzed, and their association with dialysis requirement (>10 days); severe neurological, cardiovascular, and/or bowel involvement; and death was assessed. Results: The records of 280 patients were reviewed; 160 females, median age 21 months (IQR18m). STEC O157 was isolated in 206 (73.6%) patients, O145 in 47 (16.8%), O121 in 15 (5.4%), and other serotypes in 12 (4.2%). The stx2a/2c genotype was carried by 179 (63.9%) strains, stx2a by 94 (33.6%), stx1a/stx2a by five (1.8%), and stx1a only by two (0.7%). All strains except six harbored eae and ehxA genes. Fifty-nine (21.1%) patients had severe neurological involvement, 29 (10.4%) severe bowel injury, 14 (5%) cardiovascular involvement, 53 (18.9%) required > 10 days of dialysis, and 12 (4.3%) died. Neither serotypes nor stx genotypes detected were significantly linked to severity. Conclusions: Serotype O157 and virulence stx2a/2c, eae, ehxA genotype are prevalent in Argentina, and no relationship was found between severity and serotypes and genotypes of STEC detected. [ABSTRACT FROM AUTHOR]

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Background: Gastroenteritis is a common infectious disease in children, which results in high mortality and morbidity, especially in resource-poor countries. This study presents the selected main gastroenteritis causing bacteria, including Escherichia coli O157, Salmonella and Shigella species delineating their prevalence and resistance pattern to the clinically used antibiotics. Results: A total of 346 stool specimens from children of clinically suspected gastroenteritis below five years have been obtained, and bacterial pathogens were recovered using selective media, biochemical and serologic tests. We found that 35 (10%) of them were confirmed bacterial gastroenteritis (BGE) with either Escherichia coli O157 (14%), Salmonella spp. (43%), and Shigella spp. (43%). Nevertheless, the prevalence of E. coli O157, Salmonella spp., and Shigella spp. in this study were documented as 1.45%, 4.34%, and 4.34%, respectively. Moreover, 2 (40%) of E. coli O157, 4 (26.67%) of Salmonella spp., and 14 (93%) of the Shigella spp. were found as multidrug-resistant. Nonetheless, Shigella spp. isolates showed 100%, 87%, and 73% resistance to cotrimoxazole, ciprofloxacin, and azithromycin respectively, while E. coli O157 showed 80% resistance to cotrimoxazole and 60% to ciprofloxacin and azithromycin. On the contrary, cotrimoxazole, ciprofloxacin, azithromycin, and tetracycline were resistant in 40%, 47%, 27%, and 53% of Salmonella spp. isolates respectively. Conclusion: These findings generate significant insights on the prevalence and antibiotic resistance of the three major gastroenteritis causing bacteria in the study area. Therefore, it will help physicians and policymakers selecting the right antibiotics in essential cases, particularly, reevaluation of recommending cotrimoxazole, ciprofloxacin, and azithromycin in the management of bacterial gastroenteritis. [ABSTRACT FROM AUTHOR]

Escherichia coli, the most important foodborne pathogen worldwide, can go into a state of dormancy called viable but nonculturable (VBNC) state under various stress conditions. Hence, it escapes detection by traditional culturing methods. The current research made use of Propidium monoazide (PMA)-Polymerase chain reaction (PCR) assay in order to verify whether E. coli, especially O157 strains, converted to the VBNC state under the influence of cool-warm and freeze-thaw stresses. 120 beef liver samples were collected from local markets. The samples that were positive to pathogenic E. coli were treated with cooling (4 °C)-warm and freezing (-18 °C)-thaw cycles to induce the VBNC state. Samples that demonstrated the inability to form colonies on EMB agar were tested by PMA-PCR assays to confirm the existence of VBNC E. coli. 9 samples (7.5 %) of 120 beef liver samples were positive to pathogenic E. coli by microbiological tests. Cool-warm and freeze-thaw stresses on the 9 samples led to the inability of 3 of them to grow on EMB agar plates. By using PMA-PCR assay, we found that 4 °C coolwarm cycle induced E. coli into VBNC state at a higher percentage ratio than -18 °C freeze-thaw cycle. Even though further experiments are still required, in rare cases, at - 18 °C, E. coli VBNC may lose expression of genes responsible for viability and metabolic activity. Additionally, our study evaluated the PMA-PCR assay as a rapid and accurate method to check for the presence of VBNC-associated foodborne E. coli O157. [ABSTRACT FROM AUTHOR]

The present study aims to analyze the prevalence of E. coli O157 detected in foods of animal origin by meta-analysis. The prevalence of E. coli O157 detected in the different studies was combined to provide a common prevalence estimate, and heterogeneities between studies were investigated. The study material consisted of 49 studies investigating E. coli O157 prevalence in a total of 9600 food samples, including milk and dairy products, red meat and products, poultry meat and products, and cold appetizers between the years 1997-2019 in Turkey. In the meta-analysis, the Der-Simonian-Laird method was used. Meta-analyses were performed using the R 3.6.1. As a result of the meta-analysis, the common prevalence of E. coli O157 was 0.024 (0.018-0.029). As a result of the Egger's Linear Regression Test, the study samples were found to be biased (t-value=6.092, P<0.001). To determine the source of heterogeneity between studies, sub-group and meta-regression analyses were performed in milk and dairy products, red meat and products, poultry meat and products, and ready-to-eat foods (RTEs). Accordingly, the prevalence of E. coli O157 in milk and dairy products, red meat and products, poultry meat and products, and RTEs was determined as 0.017, 0.031, 0.023, and 0.080 in Turkey, respectively. This study provides a stronger and more accurate estimation of the prevalence of E. coli O157 in foods of animal origin with the meta-analysis by eliminating inconsistencies in the effect of the sampling size of independent prevalence studies. However, in order to obtain accurate prevalence results in practice, it is necessary carefully to select the studies to be included in the analysis, to use the appropriate statistical model, and to interpret the results of the analysis correctly. [ABSTRACT FROM AUTHOR]

Cattle have been suggested as the primary reservoirs of E. coli O157 mainly as a result of colonization of the recto-anal junction (RAJ) and subsequent shedding into the environment. Although a recent study reported different gene expression at RAJ between super-shedders (SS) and non-shedders (NS), the regulatory mechanisms of altered gene expression is unknown. This study aimed to investigate whether bovine non-coding RNAs play a role in regulating the differentially expressed (DE) genes between SS and NS, thus further influencing E. coli O157 shedding behavior in the animals through studying miRNAomes of the whole gastrointestinal tract including duodenum, proximal jejunum, distal jejunum, cecum, spiral colon, descending colon and rectum. The number of miRNAs detected in each intestinal region ranged from 390 ± 13 (duodenum) to 413 ± 49 (descending colon). Comparison between SS and NS revealed the number of differentially expressed (DE) miRNAs ranged from one (in descending colon) to eight (in distal jejunum), and through the whole gut, seven miRNAs were up-regulated and seven were down-regulated in SS. The distal jejunum and rectum were the regions where the most DE miRNAs were identified (eight and seven, respectively). The miRNAs, bta-miR-378b, bta-miR-2284j, and bta-miR-2284d were down-regulated in both distal jejunum and rectum of SS (log2fold-change: −2.7 to −3.8), bta-miR-2887 was down-regulated in the rectum of SS (log2fold-change: −3.2), and bta-miR-211 and bta-miR-29d-3p were up-regulated in the rectum of SS (log2fold-change: 4.5 and 2.2). Functional analysis of these miRNAs indicated their potential regulatory role in host immune functions, including hematological system development and immune cell trafficking. Our findings suggest that altered expression of miRNA in the gut of SS may lead to differential regulation of immune functions involved in E. coli O157 super-shedding in cattle.

Cattle have been suggested as the primary reservoirs of E. coli O157 mainly as a result of colonization of the recto-anal junction (RAJ) and subsequent shedding into the environment. Although a recent study reported different gene expression at RAJ between super-shedders (SS) and non-shedders (NS), the regulatory mechanisms of altered gene expression is unknown. This study aimed to investigate whether bovine non-coding RNAs play a role in regulating the differentially expressed (DE) genes between SS and NS, thus further influencing E. coli O157 shedding behavior in the animals through studying miRNAomes of the whole gastrointestinal tract including duodenum, proximal jejunum, distal jejunum, cecum, spiral colon, descending colon and rectum. The number of miRNAs detected in each intestinal region ranged from 390 ± 13 (duodenum) to 413 ± 49 (descending colon). Comparison between SS and NS revealed the number of differentially expressed (DE) miRNAs ranged from one (in descending colon) to eight (in distal jejunum), and through the whole gut, seven miRNAs were up-regulated and seven were down-regulated in SS. The distal jejunum and rectum were the regions where the most DE miRNAs were identified (eight and seven, respectively). The miRNAs, bta-miR-378b, bta-miR-2284j, and bta-miR-2284d were down-regulated in both distal jejunum and rectum of SS (log2fold-change: −2.7 to −3.8), bta-miR-2887 was down-regulated in the rectum of SS (log2fold-change: −3.2), and bta-miR-211 and bta-miR-29d-3p were up-regulated in the rectum of SS (log2fold-change: 4.5 and 2.2). Functional analysis of these miRNAs indicated their potential regulatory role in host immune functions, including hematological system development and immune cell trafficking. Our findings suggest that altered expression of miRNA in the gut of SS may lead to differential regulation of immune functions involved in E. coli O157 super-shedding in cattle. [ABSTRACT FROM AUTHOR]

Captive amphibians and reptiles are well-documented sources of human salmonellosis through direct contact with contaminated feces or fomites. However, the relative significance of wild cold-blooded vertebrates as hosts/reservoirs of zoonotic enteric pathogens in their natural habitat is not known. Wild amphibian and reptile populations are present in the leafy green produce production environment in the central California coast, and there are reports from growers that frogs and other species sometimes intrude into produce fields. These intrusions may result in destruction of the crop and economic losses, due to food safety and quality concerns. Environmental groups have also noted potential conflicts between conservation efforts and food safety practices that result in removal or damage to aquatic habitat (e.g., farm ponds, adjacent wetland areas). To address these concerns, we conducted a survey of foodborne pathogen prevalence in common amphibian and reptile populations during the 2011 produce growing season in the central California coast. Preliminary results indicate that Salmonella prevalence was higher among wild-caught reptile (33%) compared with amphibian (4%) taxa. In contrast, all samples were negative for E. coli O157. Wildlife damage management in fresh produce production fields is challenging, due to the diversity of potential hosts/reservoirs of foodborne pathogens and a limited number of mitigation strategies. Professionals working in vertebrate pest control could play an important role in assisting fresh produce growers with implementation of co-management approaches that promote public health and conservation goals in the central coast agricultural landscape.

Abstract Background In many Asian countries including Bangladesh E. coli O157 are prevalent in animal reservoirs and in the food chain, but the incidence of human infection due to E. coli O157 is rare. One of the reasons could be inability of the organism from animal origin to produce sufficient amount of Shiga toxin (Stx), which is the main virulence factor associated with the severe sequelae of infection. This study aimed to fill out this knowledge gap by investigating the toxigenic properties and characteristics of stx phage of E. coli O157 isolated from animal sources in Bangladesh. Results We analysed 47 stx 2 positive E. coli O157 of food/animal origin for stx 2 gene variants, Shiga toxin production, presence of other virulence genes, stx phage insertion sites, presence of genes associated with functionality of stx phages (Q 933 and Q 21) and stx 2 upstream region. Of the 47 isolates, 46 were positive for both stx 2a and stx 2d while the remaining isolate was positive for stx 2d only. Reverse Passive Latex Agglutination assay (RPLA) showed that 42/47 isolates produced little or no toxin, while 5 isolates produced a high titre of toxin (64 to 128). 39/47 isolates were positive for the Toxin Non-Producing (TNP) specific regions in the stx 2 promoter. Additionally, all isolates were negative for antiterminator Q 933while a majority of isolates were positive for Q 21 gene suggesting the presence of defective stx phage. Of the yehV and wrbA phage insertion sites, yehV was found occupied in 11 isolates while wrbA site was intact in all the isolates. None of the isolates was positive for the virulence gene, cdt but all were positive for hlyA, katP, etpD and eae genes. Isolates that produced high titre Stx (n = 5) produced complete phage particles capable of infecting multiple bacterial hosts. One of these phages was shown to produce stable lysogens in host strains rendering the Stx2 producing ability. Conclusion Despite low frequency in the tested isolates, E. coli O157 isolates in Bangladesh carry inducible stx phages and have the capacity to produce Stx2, indicating a potential risk of E. coli O157 infection in humans.

A Quantitative Microbial Risk Assessment (QMRA) technique was applied to assess the public health risk from exposure to infectious microorganisms at bathing areas of three rivers in Bangladesh. The QMRA assessed the probability of illness due to the accidental ingestion of river water impacted by untreated sewage. The simplified QMRA was based on average concentrations of four reference pathogens Escherichia coli (E. coli) O157:H7, Cryptosporidium spp, norovirus and rotavirus relative to indicator bacterium E. coli. Public health risk was estimated as the probability of infection and illness from a single exposure of bathers. The risks of illness were ranged from 7 to 10% for E. coli O157:H7, 13 to 19% for Cryptosporidium, 7 to 10% for norovirus and 12 to 17% for rotavirus. The overall risk of illness at the rivers was slightly higher in children (9-19%) compared to adults (7-16%). The risks of illness in individuals exposed to the river bathing were unacceptably high, exceeding the USEPA acceptable risk of 3-6 illnesses per hundred bathing events. This study gives a basis for reducing the burden of disease in the population by applying appropriate risk management. Findings and methods of this study will be helpful for other countries with similar socio-economic and geographic settings. [ABSTRACT FROM AUTHOR]

Escherichia coli O157:H7 and Salmonella enterica are leading causes of foodborne outbreaks linked to fresh produce. Both species can enter the "viable but nonculturable" (VBNC) state that precludes detection using conventional culturebased or molecular methods. In this study, we assessed propidium monoazidequantitative PCR (PMA-qPCR) assays and novel methods combining PMA and loopmediated isothermal amplification (LAMP) for the detection and quantification of VBNC E. coli O157:H7 and S. enterica in fresh produce. The performance of PMALAMP assays targeting the wzy gene of E. coli O157:H7 and the agfA gene of S. enterica and the performance of PMA-qPCR assays were compared in pure culture and spiked tomato, lettuce, and spinach. No cross-reaction was observed in the specificity tests. The values representing the limit of detection (LOD) seen with PMA-LAMP were 9.0 CFU/reaction for E. coli O157:H7 and 4.6 CFU/reaction for S. enterica in pure culture and were 5.13 x 10³ or 5.13 x 104 CFU/g for VBNC E. coli O157:H7 and 1.05 x 104 or 1.05 x 105 CFU/g for VBNC S. enterica in fresh produce, representing results comparable to those obtained by PMA-qPCR. Standard curves showed correlation coefficients ranging from 0.925 to 0.996, indicating a good quantitative capacity of PMA-LAMP for determining populations of both bacterial species in the VBNC state. The PMA-LAMP assay was completed with considerable economy of time (30 min versus 1 h) and achieved sensitivity and quantitative capacity comparable to those seen with a PMA-qPCR assay. PMA-LAMP is a rapid, sensitive, and robust method for the detection and quantification of VBNC E. coli O157:H7 and S. enterica in fresh produce. [ABSTRACT FROM AUTHOR]