rfbE Gene Research Articles

Prevalence of multidrug-resistant Escherichia coli isolates and virulence gene expression in poultry farms in Jos, Nigeria.

Antimicrobial resistance is increasingly becoming a global health concern. This study aimed to investigate and report MDR Escherichia coli (E. coli) prevalence, resistance, and virulence genes from poultry in Jos, Plateau State, Nigeria. The samples were analyzed using microbiological standard methods and polymerase chain reactions (PCRs). A total of 179 cloacal swabs were collected from bothlocal and exotic poultry breeds, of which 99.4% (178/179) tested positive for E. coli. Among these culturally identified samples, 99.4% (177/178) were furtherconfirmed Escherichia coli with a molecular weight of 401 bp. Multidrugresistance of 45% (80/178) was observed from the confirmed isolates. PCR assays were conducted to detect genes associated with resistance to antibiotics, specifically, tetracycline (tetA gene), sulfonamide (sul1 gene), ampicillin (ampC gene), and quinolone (gyrA gene). Antimicrobial susceptibility test (AST) results revealed substantial antibiotic resistance, with 81.9% (145/177) of the isolates being resistant to tetracycline, 80.2% (142/177) to quinolone, 69.5% (123/177) to sulfonamide, and 66.1% (117/177) to ampicillin. Further analysis on 18 isolates that showed resistance to up to four different antibiotics was carried out using multiplex PCR to detect eae, hlyA, rfbE, fliC, and fstx virulence genes. The study found that 44.4% (15/18) of the isolates were positive for the eae gene, 27.7% (5/18) for stx, 22.2% (4/18) for rfbe gene, and 5.5% (1) for hlya gene, and none tested positive for fliC gene. These results showed high antibiotic resistance, virulent genes, and significant levels of MDR in E. coli from poultry. This study highlights the urgent need for antimicrobial stewardship practices within the poultry industry due to their profound implications for food safety and public health. This issue is particularly critical in Nigeria, where poultry farming constitutes a significant portion of smallholder farming practices.

Detection of Escherichia coli O157H7 and Campylobacter jejuni in Bovine Carcasses in Two Slaughterhouses in Bio-Bío District, Chile.

Escherichia coli O157:H7 (E. coli O157:H7) and Campylobacter jejuni (C. jejuni) are pathogenic microorganisms that can cause severe clinical symptoms in humans and are associated with bovine meat consumption. Specific monitoring for E. coli O157: H7 or C. jejuni in meat is not mandatory under Chilean regulations. In this study, we analyzed 544 samples for the detection of both microorganisms, obtained from 272 bovine carcasses (280 kg average) at two slaughterhouses in the Bio-Bío District, Chile. Sampling was carried out at post-shower of carcasses and after channel passage through the cold chamber. Eleven samples were found to be positive for E. coli O157:H7 (4.0%) using microbiological and biochemical detection techniques and were subjected to a multiplex PCR to detect fliC and rfbE genes. Six samples (2.2%) were also found to be positive for the pathogenicity genes stx1, stx2, and eaeA. Twenty-two carcasses (8.0%) were found to be positive for C. jejuni using microbiological and biochemical detection techniques, but no sample with amplified mapA gene was found.

Development and Application of Four Foodborne Pathogens by TaqMan Multiplex Real-Time PCR.

A TaqMan multiplex real-time PCR (mRT-PCR) was developed to detect simultaneously Salmonella spp., Escherichia coli O157, Staphylococcus aureus, and Listeria monocytogenes in food samples. The method involves four sets of primers and probes tailored to the unique DNA sequences found in the invA, nuc, rfbE, and hly genes of each pathogen. The generated standard curves, correlating gene copy numbers with Ct values, demonstrated high accuracy (R2 > 0.99) and efficiency (92%-104%). Meanwhile, the limit of detection was 100 CFU/mL for the four target bacteria in artificially contaminated food samples after 6-8 h of enrichment. The assay's effectiveness was further verified by testing 80 naturally contaminated food samples, showing results largely in agreement with traditional culture methods. Overall, this newly developed TaqMan mRT-PCR, inclusive of a pre-enrichment step, proves to be a dependable and effective tool for detecting single or multiple pathogens in diverse food items, offering significant potential for in vitro diagnostics.

On-site monitoring of Escherichia coli O157:H7 in drinking water based on rapid detection of the rfbE gene at the single copy level

The sensitive and on-site detection of highly pathogenic Escherichia coli O157:H7 (E. coli O157:H7) is of great importance to ensure public health. However, conventional methods for E. coli O157:H7 detection may suffer disadvantages such as high expense and time consumption. Herein, we reported a cost-effective colorimetric platform based on loop-mediated isothermal amplification (LAMP) for ultrasensitive and rapid detection of E. coli O157:H7. In this study, a novel quantitative colorimetric LAMP assay was established by in-situ measurement of hydroxy naphthol blue (HNB) color change with a designed portable device, which was applied to the amplification of the specific rfbE gene of E. coli O157:H7. As expected, this method featured a wide linear range (100-104 copies µL−1) with excellent linear regression analysis (R2 > 0.99) and possessed a record-low detection limit of 1 copy µL−1 to lower the risk of missed detection. The proposed strategy could be employed on drinking water samples with favorable recoveries and also demonstrated potential in the analysis of complex samples. This work exhibits the promising application prospect in on-site detection without the need for expensive instrumentation and seeks to provide an original paradigm for the rapid and sensitive detection of waterborne pathogens.

Molecular and biological Study of Colibacillosis Susceptibility in broiler

This study was aimed to Detection of virulence genes(rfbE) It was carried in College of Veterinary Medicine at Baghdad university, During a time span of November (2021) to March (2022). (100) samples were collected from diarrheal chicken . 100 chicks were used in the present study, One day old chicks were weighed (Average of chick weight was 160 gm±2) then transferred to the poultry house. Chicks in wards that were divided by wood barriers. Diagnosis of bacterial colonies were first done by the bacteriological methods. From (100) fecal samples of diarrheal cases of chicken , 90(90%) isolates were Escherichia coli.In the present study using vitek 2 compact system and Api 20 Escherichia coli. for the identification isolated bacteria. PCR technique was used to Detection of virulence genes(rfbE) ,The result for rfbE gene in this study was showed that this gene was detected in(60) isolates of (90) samples of chicken observed carried the rfbE gene which represent (67%).

A propidium monoazide-polymerase spiral reaction (PMA-PSR) designed for direct detection of Escherichia coli O157:H7 viable cell

Escherichia coli O157:H7 is a major foodborne pathogen causing food poisoning. Standard detection method for foodborne E. coli is plate counting, which is time consuming and omits VBNC cells. PSR is an isothermal amplification technique identifying trace amount DNA. However, its effectiveness is influenced by residual DNA from dead cells. This study aimed at designing a PMA-PSR system for accurate determination of viable cells of E. coli O157:H7. Firstly, PSR was optimized in fluorescence indicator, betaine concentration and reaction time. The optimized system could successfully identify rfbE, stx1 and stx2 genes within 45 min at 65 °C. Secondly, sensitivity and specificity were tested in pure culture and different food samples. With 100% specificity, PSR could determine DNA amount as low as 1.12 pg/μL. Thirdly, a PMA-PSR system was designed for accurate determination of viable cells. Cells were treated with 5 μg/mL PMA to remove residual DNA from dead cells. Pretreated cells were adapted to PSR, thus viable cells were specifically detected. Fourthly, the system was applied in food samples with VBNC cells. Viable cells could be accurately determined in accordance with regular assay. In conclusion, the PMA-PSR system was an efficient tool for accurate determination of E. coli O157:H7 viable cells.

Antibiotic resistant shiga toxin producing Escherichia coli isolates from milk and milk products

Totally 450 milk and milk products (50 each of raw buffalo & cow milk; Kareish, Tallaga and Roquefort cheeses; yoghurt; rayeb; condensed milk and sour cream) samples were randomly purchased from various markets in Kafr El-Sheikh for isolation and identification of STEC. Results showed that 60%, 80%, 30%, 10%, 12%, 20%, 6% and 22% of buffalo & cow milk, Kareish, Roquefort, Tallaga, yoghurt, rayeb and sour cream respectively, contained E.coli, but negative in condensed milk. Fifty suspected isolates were serologically identified using E.coli O157:H7 kits, and confirmed in 69.2%, 53.8%, 60%, 16.7% and 20% isolates of buffalo & cow milk, Kareish, Tallaga and yoghurt, while was negative in Roqufort, rayeb, and sour cream. Using PCR assay, 21 confirmed isolates were examined, 44.4, 71.4, 66.7, 100 and 100% isolates of buffalo & cow milk, Kareish, Tallaga and yoghurt were positive for rfbE gene; while 55.6, 42.8, 66.7, 100 and 100 % isolates of buffalo & cow milk, Kareish, Tallaga and yoghurt were positive for blaTEM, but all isolates were negative for blaCMY2. Consequently, raw milk and most dairy products including fermented products were possible source of E.coli O157:H7food poisoning, so usage of accurate hygienic measures through manufacture and retail of milk products be essential.

Molecular Evaluation of rfbE Gene Expression Changes under Different Creatinine Concentrations in Escherichia coli Strains Via Real-Time PCR

Background and objective. Escherichia coli (E. coli) O157: H7 as an enterohemorrhagic pathogen causes severe damage to the gastrointestinal tract and dangerous diseases in humans such as hemolytic uremic syndrome (HUS) and acute renal failure, which is associated with increased blood creatinine levels. This study aimed to evaluate antibiotic resistance of E. coli O157: H7 pathotypes to detect the virulence of gene rfbE and to study variations in its expression. Methods. The isolates were first inoculated on eosin methylene blue (EMB) agar and then identified using the Microgen kit and the presence of rfbE gene. Antibiotic susceptibility of the identified strains was tested by the disk diffusion technique, followed by inoculating E. coli O157: H7 strains at concentrations of 1, 3, and 6 mg dl–1 in BHI broth. DNA and RNA were then extracted from the bacteria, and cDNA was prepared from purified RNA. Then, the rfbE gene expression was evaluated using a real-time PCR approach, and the data were analysed with Rest software. Results. The research results revealed high resistance of isolated strains against some of the studied antibiotics, and variations in the expression of the rfbE gene were found to be different at different creatinine concentrations and at different time points. A significant decrease in variations in the rfbE gene expression was observed at low concentrations (1 mg dl-1), but, on the contrary, a significant increase in variations in the rfbE gene expression was found at higher concentrations (3 and 6 mg dl-1) (p<0.05). Conclusions. The rfbE gene is one of the factors affecting the bacterial virulence. We believe that a secondary increase in creatinine for any reason can exacerbate kidney disease and failure by affecting the rfbE gene expression while producing O antigen or bacterial endotoxin.

Multiplex Real-Time PCR for the Detection of Shiga Toxin-Producing Escherichia coli in Foods.

Shiga toxin-producing Escherichia coli (STEC) is a group of human foodborne pathogens transmitted to humans through the consumption of different types of food. Their detection is mainly performed by targeting specific serogroups by classical microbiological methods and, later, by molecular typing with different techniques. The application of multiplex real-time PCR (qPCR) can significantly improve the turnaround time of the existing methodologies as in one single run it is possible to detect and characterize specific microorganisms. In the present chapter, a pentaplex qPCR assay is described for the identification of STEC which may also be applied for the rapid screening of these pathogens in different types of foods. The assay targets the most important virulence factors of these microorganisms, the genes stx1, stx2, and eae, along with the rfbE gene which encodes for the "O157" antigen as this is the most prevalent serogroup among all STEC, as well as an internal amplification control to rule out false-negative results due to qPCR inhibition.

Target nucleic acid amplification-free detection of Escherichia coli O157:H7 by CRISPR/Cas12a and hybridization chain reaction based on an evanescent wave fluorescence biosensor

As the main foodborne pathogen, Escherichia coli O157:H7 poses a serious threat to public health. Herein, a target nucleic acid amplification-free method was developed integrating a hybridization chain reaction and CRISPR/Cas12a called the CHANCE (Cas12a-HCR evANescent wave fluorescenCE) system for the rapid and sensitive detection of E. coli O157:H7. The specific crRNA was designed with the rfbE gene of E. coli O157:H7 as the target. In the presence of the target, the trans-cleavage activity of Cas12a is activated and cleaves the HCR initiator, resulting in a decrease in the fluorescence signal. Under the optimized conditions, the CHANCE method could quantify E. coli O157:H7 with a concentration range from 10 to 108 CFU/mL, with a detection limit of 17.4 CFU/mL. By using the rapid extraction method, the accurate detection of E. coli O157:H7 can be achieved within 50 min and successfully applied in actual environmental water samples. Benefiting from free amplification and high flexibility, the CHANCE method provides an ideal alternative tool for the rapid and on-site detection of pathogenic bacteria in the environment and food.

Point-of-Care Lateral Flow Detection of Viable Escherichia coli O157:H7 Using an Improved Propidium Monoazide-Recombinase Polymerase Amplification Method

The detection of both viable and viable but non-culturable (VBNC) Escherichia coli O157:H7 is a crucial part of food safety. Traditional culture-dependent methods are lengthy, expensive, laborious, and unable to detect VBNC. Hence, there is a need to develop a rapid, simple, and cost-effective detection method to differentiate between viable/dead E. coli O157:H7 and detect VBNC cells. In this work, recombinase polymerase amplification (RPA) was developed for the detection of viable E. coli O157:H7 through integration with propidium monoazide (PMAxx). Initially, two primer sets, targeting two different genes (rfbE and stx) were selected, and DNA amplification by RPA combined with PMAxx treatment and the lateral flow assay (LFA) was carried out. Subsequently, the rfbE gene target was found to be more effective in inhibiting the amplification from dead cells and detecting only viable E. coli O157:H7. The assay’s detection limit was found to be 102 CFU/mL for VBNC E. coli O157:H7 when applied to spiked commercial beverages including milk, apple juice, and drinking water. pH values from 3 to 11 showed no significant effect on the efficacy of the assay. The PMAxx-RPA-LFA was completed at 39 °C within 40 min. This study introduces a rapid, robust, reliable, and reproducible method for detecting viable bacterial counts. In conclusion, the optimised assay has the potential to be used by the food and beverage industry in quality assurance related to E. coli O157:H7.

Simultaneous Detection of Five Foodborne Pathogens Using a Mini Automatic Nucleic Acid Extractor Combined with Recombinase Polymerase Amplification and Lateral Flow Immunoassay.

In recent years, foodborne disease outbreaks have caused huge losses to the economy and have had severe impacts on public health. The accuracy and variety of detection techniques is crucial to controlling the outbreak and spread of foodborne diseases. The need for instruments increases the difficulty of field detection, while manually-handled samples are subject to user error and subjective interpretation. Here, we use a mini automatic nucleic acid extractor combined with recombinant polymerase amplification (RPA) and lateral flow immunoassay (LFIA) for simultaneous quantitative detection of five major foodborne pathogens. The pre-treatment device using the magnetic bead method allows for nucleic acid extraction of the reagent tank without manual operation, which is highly efficient and stable for preventing aerosol contamination. The nuc gene of Staphylococcus aureus, the toxR gene of Vibrio parahaemolyticus, the rfbE gene of Escherichia coli O157:H7, the hlyA gene of Listeria monocytogenes, and the fimY gene of Salmonella enterica were used as target fragments. The labeled antibody concentration is optimized on the LFIA to find the equilibrium point for the binding capacity of the five chemical markers and to efficiently and accurately visualize the bands. The RPA assay shows an optimal performance at 37 °C for 15 min. The optimized RPA-LFIA detection limit can reach 101 CFU/mL. There was no cross-reactivity among forty-eight strains. Furthermore, the average recoveries in spiked food samples were 90.5–104.5%. In summary, the RPA-LFIA established in this study can detect five pathogenic bacteria simultaneously with little dependence on laboratory equipment, and it has promising prospects for screening in low-resource areas.

High Frequency (100, 150 MHz) Quartz Crystal Microbalance (QCM) Piezoelectric Genosensor for the Determination of the Escherichia coli O157 rfbE Gene

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.

Molecular detection and phylogenetic analysis of a Shiga toxin-producing strain Escherichia coli (partial rfbE and fliCh7 gene), serotype O157:H7 isolated from a living chicken of a traditional market in Indonesia

The objective of this study was to identify a Shiga toxin-producing strain Escherichia coli partial rfbE and fliCh7 gene of O157:H7 isolated from a faeces sample collected from a live chicken in a traditional market in Bogor, Indonesia. The isolate was investigated using multiplex polymerase chain reaction (PCR) to detect stx1, stx2, rfbE, and fliCh7 gene of STEC O157:H7. Then, sequencing was applied to identify the antigen markers, which are the rfbE and fliCh7 genes. In the present study, the isolate which was obtained from a live chicken was successfully identified as STEC O157:H7 strain. This conclusion was based on multiplex PCR and a nucleotide sequence analysis. This pathogen was not only found in the live chicken, but it was further suggested that the rfbE and fliCh7 genes can be used as alternative targets for molecular identification of this pathogen.

Rapid nucleic acid detection of Escherichia coli O157:H7 based on CRISPR/Cas12a system

Escherichia coli O157:H7 ( E. coli O157:H7) is one of the most dangerous foodborne pathogens causing severe illnesses in the elderly, children and immunocompromised people. Traditional methods could not meet the detection requirements of high speed, sensitivity, and specificity. The clustered regularly interspaced short palindromic repeats (CRISPR)-based diagnostic is a novel high sensitivity and specificity detection method. In this study, a rapid nucleic acid of Escherichia coli O157:H7 was detected using rfbE gene based on CRISPR/Cas12a system. The limit of detection for DNA and bacterial concentrations was 0.9 pg/μL and 6.5 × 10 4 CFU/mL, respectively. Furthermore, when the initial bacterial inoculum was 14 CFU/mL in the ground beef sample, the target was detected after 4 h of culture through Metal Organic Framework immunomagnetic beads (Fe 3 O 4 @PDA@UiO-66-NH 2 ) enrichment. • A rapid detection method based on CRISPR/Cas12a system to detect E. coli O157: H7. • CRISPR/Cas12a system was more accurate and better than g-MIRA and RT-PCR. • CRISPR/Cas12a system demonstrated the limit of 14 CFU⋅mL −1 in beef within 4h. • The detection time was 1 h earlier enriched by immunomagnetic beads.

Engineering a Novel Bivalent Oral Vaccine against Enteric Fever.

Enteric fever is a major global healthcare issue caused largely by Salmonella enterica serovars Typhi and Paratyphi A. The objective of this study was to develop a novel, bivalent oral vaccine capable of protecting against both serovars. Our approach centred on genetically engineering the attenuated S. Typhi ZH9 strain, which has an excellent safety record in clinical trials, to introduce two S. Paratyphi A immunogenic elements: flagellin H:a and lipopolysaccharide (LPS) O:2. We first replaced the native S. Typhi fliC gene encoding flagellin with the highly homologous fliC gene from S. Paratyphi A using Xer-cise technology. Next, we replaced the S. Typhi rfbE gene encoding tyvelose epimerase with a spacer sequence to enable the sustained expression of O:2 LPS and prevent its conversion to O:9 through tyvelose epimerase activity. The resulting new strain, ZH9PA, incorporated these two genetic changes and exhibited comparable growth kinetics to the parental ZH9 strain. A formulation containing both ZH9 and ZH9PA strains together constitutes a new bivalent vaccine candidate that targets both S. Typhi and S. Paratyphi A antigens to address a major global healthcare gap for enteric fever prophylaxis. This vaccine is now being tested in a Phase I clinical trial (NCT04349553).

Evaluation and comparison of recombinase polymerase amplification coupled with lateral-flow bioassay for Escherichia coli O157:H7 detection using different genes

Shiga toxin-producing Escherichia coli serotype O157:H7 is a food and waterborne zoonotic pathogen causing gastroenteritis in humans. Rapid and simple detection in water and food is imperative to control its spread. However, traditional microbial detection approaches are time-consuming, expensive and complex to operate at the point-of-care without professional training. We present a rapid, simple, sensitive, specific and portable method for detection of E. coli O157:H7 in drinking water, apple juice and milk. We evaluated the effect of gene selection in detecting E. coli O157:H7 using recombinase polymerase amplification coupled with a lateral flow assay using rfbE, fliC and stx gene targets. As low as 100 ag and 1 fg DNA, 4–5 CFU/mL and 101 CFU/mL of E. coli O157:H7 was detected using the stx and rfbE gene targets respectively with 100% specificity, whilst the detection limit was 10 fg DNA and 102 CFU/mL for the fliC gene target, with 72.8% specificity. The RPA-LFA can be completed within 8 min at temperatures between 37 and 42 °C with reduced handling and simple equipment requirements. The test threshold amplification of the target was achieved in 5–30 min of incubation. In conclusion, RPA-LFA represents a potential rapid and effective alternative to conventional methods for the monitoring of E. coli O157:H7 in food and water.

Comparative Use of Quantitative PCR (qPCR), Droplet Digital PCR (ddPCR), and Recombinase Polymerase Amplification (RPA) in the Detection of Shiga Toxin-Producing E. coli (STEC) in Environmental Samples

E. coli O157:H7 is a foodborne pathogen that constitutes a global threat to human health. However, the quantification of this pathogen in food and environmental samples may be problematic at the low cell numbers commonly encountered in environmental samples. In this study, we used recombinase polymerase amplification (RPA) for the detection of E. coli O157:H7, real-time quantitative PCR (qPCR) for quantification, and droplet digital PCR (ddPCR) for absolute and accurate quantification of E. coli O157:H7 from spiked and environmental samples. Primer and probe sets were used for the detection of stx1 and stx2 using RPA. Genes encoding for stx1, stx2, eae, and rfbE were used to quantify E. coli O157:H7 in the water samples. Furthermore, duplex ddPCR assays were used to quantify the pathogens in these samples. Duplex assay set 1 used stx1 and rfbE genes, while assay set 2 used stx2 and eae genes. Droplet digital PCR was used for the absolute quantification of E. coli O15:H7 in comparison with qPCR for the spiked and environmental samples. The RPA results were compared to those from qPCR and ddPCR in order to assess the efficiency of the RPA compared with the PCR methods. The assays were further applied to the dairy lagoon effluent (DLE) and the high rate algae pond (HRAP) effluent, which were fed with diluted DLE. The RPA detected was <10 CFU/mL, while ddPCR showed quantification from 1 to 104 CFU/mL with a high reproducibility. In addition, quantification by qPCR was from 103 to 107 CFU/mL of the wastewater samples. Therefore, the RPA assay has potential as a point of care tool for the detection of E. coli O157:H7 from different environmental sources, followed by quantification of the target concentrations.

MOLECULAR IDENTIFICATION OF E. COLI O157:H7, VIRULENCE GENES AND QUINOLONE / FLUOROQUINOLONE RESISTANT GENES AMONG E. COLI ISOLATES FROM RETAILED MEAT IN IBADAN, SOUTHWEST NIGERIA

Escherichia coli is classified based on their pathogenicity factor, the strain E. coli O157:H7 is implicated in diarrhoea leading to haemolytic uremic syndrome. Therefore this study identified E. coli O157:H7, virulence and quinolone/fluoroquinolone resistant genes in Escherichia coli isolates from meat. Isolates of Escherichia coli from meat were identified by standard laboratory methods using Microbact GNB 12E (Oxoid), E. coli O157:H7 was identified by serotyping and the presence of virulence gene was determined by molecular methods. Antibiotic susceptibility of E. coli and quinolone/fluoroquinolone resistance (qnr) genes were determined using disc diffusion and molecular methods respectively. Out of the 130 E. coli identified, 72 (55.4%) were resistant to at least one or more of the antibiotics tested including quinolone/fluoroquinolones. E. coli O157:H7 were detected serologically 5 (3.9%) and by the multiplex PCR 8 (6.2%) out of which, 2 (25%) carried eaeA, hly, rfbE and flich genes, 7 1(12.5%) carries eaeA, rfbE and hly genes, 1(12.5%) carries hly, rfbE, flich and stx2 genes, 3(37.5%) 7 carries hly, rfbE and flich genes, 1 (12.5%) carries rfbE and hly genes while none of the isolates have 7 stx1 genes. Quinolone resistant genes (qnr) was harboured by 41 (56.9%) of which 5 (3.9%) and 36(27.7%) isolates carried qnrA and qnrB, respectively. Only 2 (50%) of the E. coli O157:H7 harbour qnrB, no qnrA was detected. The E. coli isolated from meat carries virulence and qnr resistance gene which could be potential vehicles for spread of multi-drug resistant to humans.

Prevalence of Salmonella spp. and Escherichia coli O157 in a red deer herd (Cervus elaphus scoticus) in central Mexico

The primary objective was to evaluate the prevalence of Salmonella spp. and Escherichia coli O157 in feces of Cervus elaphus scoticus during summer and winter of 2015 to 2017. Additionally, the seasonality and environmental conditions were evaluated to investigate association with pathogen shedding. Preliminary evaluation of Salmonella spp. detection was achieved by PCR-amplification of the invA , spvR , and sopB genes, whereas for E. coli O157, the eae and rfbE genes were amplified. Candidate genes with low limit detection were not used to evaluate the prevalence of target pathogens. Red deer fecal samples (n = 89) were evaluated to detect invA and rfbE genes. The results showed that E. coli O157 prevalence was 0%, due to rfbE being absent; nevertheless, Salmonella spp. prevalence identified through the invA gene amplification was 56.2%, with the least prevalence during winter 2017. A positive correlation was observed between bacterial prevalence, atmospheric humidity, and temperature. The results showed that E. coli O157 was not detected in the stool of captive red deer; however, Salmonella spp. were present. Therefore, good practices in food handling and hygiene are indispensable to avoid the emergence of foodborne diseases.