Eae Gene Research Articles

Identification and Genomic Characterization of Escherichia albertii in Migratory Birds from Poyang Lake, China

Escherichia albertii is an emerging zoonotic foodborne enteropathogen leading to human gastroenteritis outbreaks. Although E. albertii has been isolated from birds which have been considered as the potential reservoirs of this bacterium, its prevalence in migratory birds has rarely been described. In this study, E. albertii in migratory birds from Poyang Lake was investigated and characterized using whole genome sequencing. Eighty-one fecal samples from nine species of migratory birds were collected and 24/81 (29.6%) tested PCR-positive for E. albertii-specific genes. A total of 47 isolates was recovered from 18 out of 24 PCR-positive samples. All isolates carried eae and cdtB genes. These isolates were classified into eight E. albertii O-genotypes (EAOgs) (including three novel EAOgs) and three E. albertii H-genotypes (EAHgs). Whole genome phylogeny separated migratory bird-derived isolates into different lineages, some isolates in this study were phylogenetically closely grouped with poultry-derived or patient-derived strains. Our findings showed that migratory birds may serve as an important reservoir for heterogeneous E. albertii, thereby acting as potential transmission vehicles of E. albertii to humans.

Extended Spectrum β-Lactamase-Producing Escherichia coli from Poultry and Wild Birds (Sparrow) in Djelfa (Algeria), with Frequent Detection of CTX-M-14 in Sparrow.

Antimicrobial resistance is a global threat that is spreading more and more in both human and animal niches. This study investigates the antimicrobial resistance and virulence threats of Escherichia coli isolates recovered from intestinal and fecal samples of 100 chickens, 60 turkeys, and 30 sparrows. Extended spectrum β-lactamase (ESBL) producing E. coli isolates were recovered in 12 of the animals tested, selecting one isolate per positive animal: sparrow (eight isolates, 26.7%), turkey (three isolates, 5%), and chicken (one isolate, 1%). The E. coli isolates were ascribed to B1 and D phylogenetic groups. The blaCTX-M-14 gene was detected in all ESBL-producing E. coli isolates from sparrow. The blaCTX-M-15 (two isolates) and blaCTX-M-14 genes (one isolate) were detected in the isolates of turkey, and the blaCTX-M-1 gene in one isolate from broiler. Three lineages were revealed among the tested isolates (ST/phylogenetic group/type of ESBL/origin): ST117/D/CTX-M-1/broiler, ST4492 (CC405)/D/CTX-M-15/turkey, and ST602/B1/CTX-M-14/sparrow. All isolates were negative for stx1, sxt2, and eae virulence genes. Our findings provide evidence that the sparrow could be a vector in the dissemination of ESBL-producing E. coli isolates to other environments. This study also reports, to our knowledge, the first detection of blaCTX-M-14 from sparrow at a global level and in turkey in Algeria.

A step forward for Shiga toxin-producing Escherichia coli identification and characterization in raw milk using long-read metagenomics.

Shiga toxin-producing Escherichia coli (STEC) are a cause of severe human illness and are frequently associated with haemolytic uraemic syndrome (HUS) in children. It remains difficult to identify virulence factors for STEC that absolutely predict the potential to cause human disease. In addition to the Shiga-toxin (stx genes), many additional factors have been reported, such as intimin (eae gene), which is clearly an aggravating factor for developing HUS. Current STEC detection methods classically rely on real-time PCR (qPCR) to detect the presence of the key virulence markers (stx and eae). Although qPCR gives an insight into the presence of these virulence markers, it is not appropriate for confirming their presence in the same strain. Therefore, isolation steps are necessary to confirm STEC viability and characterize STEC genomes. While STEC isolation is laborious and time-consuming, metagenomics has the potential to accelerate the STEC characterization process in an isolation-free manner. Recently, short-read sequencing metagenomics have been applied for this purpose, but assembly quality and contiguity suffer from the high proportion of mobile genetic elements occurring in STEC strains. To circumvent this problem, we used long-read sequencing metagenomics for identifying eae-positive STEC strains using raw cow's milk as a causative matrix for STEC food-borne outbreaks. By comparing enrichment conditions, optimizing library preparation for MinION sequencing and generating an easy-to-use STEC characterization pipeline, the direct identification of an eae-positive STEC strain was successful after enrichment of artificially contaminated raw cow's milk samples at a contamination level as low as 5 c.f.u. ml-1. Our newly developed method combines optimized enrichment conditions of STEC in raw milk in combination with a complete STEC analysis pipeline from long-read sequencing metagenomics data. This study shows the potential of the innovative methodology for characterizing STEC strains from complex matrices. Further developments will nonetheless be necessary for this method to be applied in STEC surveillance.

Isolation, characterization, and antimicrobial susceptibility pattern of Escherichia coli O157:H7 from foods of bovine origin in Mekelle, Tigray, Ethiopia.

Escherichia coli O157:H7 is an emerging and major zoonotic foodborne pathogen. It has an increasing concern about the spread of antimicrobial-resistant strains. This study aimed to isolate and characterize Shiga toxin-producing E. coli O157:H7 from raw milk, yogurt, and meat of bovine origin and determine their antimicrobial susceptibility pattern. A cross-sectional study was conducted from December 2014 to June 2015, and a total of 284 milk and meat samples were collected from different sources in Mekelle. The collected samples were analyzed for the presence of E. coli and Shiga toxin-producing E. coli O157:H7 and the determination of their antimicrobial susceptibility pattern following the standard bacteriological and molecular techniques and procedures and antimicrobial sensitivity test. Out of the total 284 samples, 70 (24.6%) were bacteriologically positive for E. coli and 14.3% were found to be Shiga toxin-producing E. coli O157:H7. Of note, 100% of E. coli isolates carried the pal gene and 41.7% eaeA gene (EHEC). Of these EHEC isolates, 40% and 60% were positive for stx1 and stx2, respectively. E. coli isolates showed the highest level of susceptibility to gentamycin (91.7%) but the highest level of resistance to amoxicillin (95.8%). Of the tested isolates, 18 (75%) of E. coli showed multidrug-resistant. This study revealed the occurrence of Shiga toxin-producing E. coli O157:H7 in foods of bovine origin in the study area. In conclusion, a nationwide phenotypic and molecular characterization, in-depth typing, and drug-resistant gene identification of E. coli O157:H7 should be undertaken.

Molecular analysis of enteropathogenic Escherichia coli (EPEC) isolates from healthy food-producing animals and humans with diarrhoea.

Enteropathogenic Escherichia coli (EPEC) is a pathogen associated with acute diarrhoea in humans. To determine whether EPEC isolated from healthy food-producing animals possesses the same virulence gene repertoire as EPEC isolated from human with diarrhoea, we compared six typical EPEC (tEPEC) and 20 atypical EPEC (aEPEC) from humans with diarrhoea and 42 aEPEC from healthy animals (swine, sheep and buffaloes), using pulsed-field gel electrophoresis (PFGE), virulence markers, serotyping and subtyping of eae and tir genes. We found that human and animal isolates shared virulence genes, including nleB, nleE and nleF, which were associated with human diarrhoea. Serogroups and serotypes identified in isolates of food-producing animals such as O26:H11, O128:H2, O76:H7, O103, O108, O111 and O145, have previously been implicated in human disease. The subtypes eae and tir were also shared between human and animal isolates, being eae-γ1 and eae-β1 the most prevalent in both groups, while the most common tir subtypes were α and β. Despite PFGE analysis demonstrating that EPEC strains are heterogeneous and there was no prevalent clone identified, EPEC isolated from humans and food-producing animals shared some characteristics, such as virulence genes associated with human diarrhoea, indicating that food-producing animals could play a role as reservoirs for those genes.

Occurrence and Characteristics of Escherichia albertii in Wild Birds and Poultry Flocks in Switzerland.

Escherichia albertii, a zoonotic pathogen, has sporadically been associated with infectious diarrhea in humans. Poultry and wild birds are considered potential reservoirs. We assessed the occurrence of E. albertii in 280 fecal samples from wild birds (n = 130) and pooled fecal samples collected at slaughterhouse level from poultry flocks (n = 150) in Switzerland. Using an E. albertii-specific PCR targeting the Eacdt gene, 23.8% (31/130) of the samples from wild birds, but not from the pooled poultry fecal samples, tested positive for Eacdt. The positive samples originated from 11 bird species belonging to eight families. Strain isolation was attempted on the PCR-positive samples by subculturing the broth cultures onto xylose-MacConkey plates. Isolation was possible on 12 of the 31 Eacdt-PCR-positive samples. Whole-genome sequencing revealed that the strains belonged to nine distinct sequence types, with ST13420 and ST5967 being represented by two and three isolates, respectively. All strains harbored the eae gene, while two strains were also positive for stx2f. Our study thus shows that E. albertii is present in the Swiss wild bird population, which can potentially act as a source of this pathogen to humans, other animals, and the environment.

Development of a Novel Real-Time Polymerase Chain Reaction Assay to Detect Escherichia albertii in Chicken Meat.

Escherichia albertii is an emerging enteropathogen. Several foodborne outbreaks of E. albertii have been reported in Japan; however, foods associated with most outbreaks remain unidentified. Therefore, polymerase chain reaction (PCR) assays detecting E. albertii specifically and sensitively are required. Primers and probe for real-time PCR assays targeting E. albertii-specific gene (EA-rtPCR) was designed. With 74 strains, including 43 E. albertii strains and several of its close relatives, EA-rtPCR specifically amplified E. albertii; therefore, the sensitivity of EA-rtPCR was then evaluated. The detection limits were 2.8 and 2.0-3.2 log colony-forming unit (CFU)/mL for E. albertii culture and enriched chicken culture inoculated with the pathogen, respectively. In addition, E. albertii was detected from 25 g of chicken meat inoculated with 0.1 log CFU of the pathogen by EA-rtPCR. The detection of E. albertii from chicken meat by EA-rtPCR was also evaluated by comparing with the nested-PCR assay, and 28 retail chicken meat and 193 dissected body parts from 21 chicken carcass were tested. One and three chicken meat were positive in the nested-PCR assay and EA-rtPCR, respectively. Fourteen carcasses had at least one body part that was positive for EA-rtPCR, and 36 and 48 samples were positive for the nested-PCR assay and EA-rtPCR, respectively. A total of 37 strains of E. albertii were isolated from seven PCR-positive samples obtained from six chicken carcass. All E. albertii isolates harbored eae gene, and were classified as E. albertii O-genotype (EAOg)3 or EAOg4 by EAO-genotyping. The EA-rtPCR developed in this study has potential to improve E. albertii detection in food and advance research on E. albertii infection.

Virulence Characteristics, Antibiotic Resistance Patterns and Molecular Typing of Enteropathogenic Producing Escherichia coli (EPEC) Isolates in Eastern Province of Saudi Arabia: 2013-2014.

The Kingdom of Saudi Arabia has limited data on enteropathogenic Escherichia coli (EPEC). Therefore, this study was undertaken to contribute to EPEC surveillance and investigate the molecular epidemiology of EPEC strains that have been implicated in human infection in King Fahd Hospital of the University (KFHU) between 2013 and 2014 in the Eastern Province of Saudi Arabia. A total of 60 non-duplicate E. coli isolates associated with human gastroenteritis were included in this study. They were characterized using PCR to determine virulence genes, antimicrobial resistance patterns, and enterobacterial repetitive intergenic consensus (ERIC-PCR). Among the 60 strains, 20% of those examined were positive for the intimin eae and bfpA genes and identified as typical EPEC (tEPEC). Furthermore, 44 of E. coli strains tested positive for the eae gene only and revealed a high occurrence rate of 73.3% of atypical EPEC (aEPEC) within the overall examined strains. All strains were positive for the EAST1 gene, and none tested positive for the stx gene. More than 70% of EPEC strains were multi-drug resistant (MDR) and aEPEC strains with the highest proportion of this feature of MDR. ERIC-PCR fingerprint revealed a total of 19 ERIC types with eight related distinct clusters and a similarity rate cut-off with ≥90% homology from the identified isolates. A high antibiotic resistance rate was reported for first-line antibiotics, such as ampicillin, tetracycline, nalidixic acid, trimethoprim-sulfamethoxazole, noroxin, and ciprofloxacin.

The Ability of Shiga Toxin-Producing Escherichia coli to Grow in Raw Cow's Milk Stored at Low Temperatures.

Despite the lack of scientific evidence, some consumers assert that raw milk is a natural food with nutritional and immunological properties superior to pasteurized milk. This has led to the increased popularity of unpasteurized cow milk (UPM) and disregard for the risks of being exposed to zoonotic infections. Dairy cattle are healthy carriers of Shiga toxin (Stx)-producing E. coli (STEC), and contaminated UPM has caused STEC outbreaks worldwide. The association between STEC, carrying the eae (E. coli attachment effacement) gene, and severe diseases is well-established. We have previously isolated four eae positive STEC isolates from two neighboring dairy farms in the Southeast of Norway. A whole genome analysis revealed that isolates from different farms exhibited nearly identical genetic profiles. To explore the risks associated with drinking UPM, we examined the ability of the isolates to produce Stx and their growth in UPM at different temperatures. All the isolates produced Stx and one of the isolates was able to propagate in UPM at 8 °C (p < 0.02). Altogether, these results highlight the risk for STEC infections associated with the consumption of UPM.

STEC non-0157 strains in meat from Southern Sonora, Mexico and its antibiotic resistance

Escherichia coli is one of the most important bacteria associated with the consumption of meat products causing human disease, with bovines as the main reservoir for this organism. Microbiological quality of raw meat sampled at slaughterhouses was evaluated by measuring the presence of Escherichia coli serogroups that produce the Shiga toxin (referred to as STEC), including both O157:H7 and non-O157 strains can cause Hemolytic Uremic Syndrome (HUS). The purpose of this study was to detect STEC O157 and non-O157 in meat products from Federal Inspection Type (FIT, n=52) and non-FIT (n=88) slaughterhouses, as well as butcheries (n=50), in southern Sonora, Mexico. To achieve this aim, selective media were employed to obtain putative O157:H7 colonies (TS-SMAC agar and Rainbow® agar O157), followed by multiplex PCR for the stx1, stx2, eaeA, and rfB genes, using the O157:H7 serotype as a control. No STEC O157 was found in beef products, but some non-O157 isolates were found containing the stx2 pathogenicity gene (1.40%, 3/224) and/or the fliCH4 flagellar antigen (1.78%, 4/224). This work also confirmed the susceptibility of strains with the stx2 and/or fliCH4 genes to several antibiotics and multi-resistance of all or some of these strains to trimethoprim/sulfamethoxazole, tetracycline, clarithromycin, penicillin G, oxacillin, ampicillin and cefazolin. This study comprises the first report of STEC non-O157 in Sonora and will be useful to establish their association with foodborne outbreaks originating from beef and pork consumption in the future.

First isolation of verocytotoxin-producing Escherichia coli O157:H7 from sports animals in Southern Thailand.

Escherichia coli O157:H7 is enterohemorrhagic E. coli, which produces verocytotoxin or Shiga toxin. It is a well-known cause of severe diseases in humans worldwide. Cattle and other ruminants are the main reservoirs of this organism. Sports animals, such as fighting bulls, riding horses, and fighting cocks, are economic animals in Southern Thailand. This study aimed to identify E. coli O157:H7 from the rectal swabs of these sports animals and determine the antimicrobial susceptibility patterns of isolated bacteria. The rectal swabs were collected from 34 fighting bulls, 32 riding horses, and 31 fighting cocks. The swabs were cultured on MacConkey (MAC) Agar; the suspected colonies were then identified by VITEK® 2 GN card, and the antimicrobial susceptibility was tested by VITEK® 2 AST N194 in VITEK® 2 Compact automation. Escherichia coli O157:H7 was confirmed by culturing on sorbitol MAC agar, the ability to grow at 44°C, and the presence of H7 antigen. In addition, the eaeA (E. coli attaching and effacing), along with stx1 and stx2 (Shiga cytotoxins) genes, were determined using polymerase chain reaction. Finally, the cytotoxicity of Shiga toxin was confirmed using the Vero cytotoxicity test. Fifty-five suspected isolates (56.70%), which were collected from 19 fighting bulls (55.88%), 13 riding horses (40.63%), and 23 fighting cocks (71.13%), were identified as E. coli. However, one sample (Bull H9/1) from fighting bulls had an equal confidence level (50%) for E. coli and E. coli O157. The confirmation of this isolate demonstrated that it was sorbitol non-fermenter, could assimilate L-lactate, was unable to grow well at 44°C, and reacted with anti-serum to H7 antigen. In addition, it was positive with stx2 and eaeA genes, and the toxin affected Vero cells by a dose-dependent response. The antimicrobial susceptibility test revealed that five out of 55 (9.09%) E. coli isolates were resistant to antimicrobial agents. All five isolates (21.74%) were collected from fighting cocks. Escherichia coli Cock H4/3 was only one of the five isolates resistant to three antimicrobial agents (ciprofloxacin, moxifloxacin, and trimethoprim/sulfamethoxazole). Fortunately, it was not multidrug-resistant bacteria. This is the first report on detection of E. coli O157:H7 in fighting bulls and antibiotic-resistant characteristic of E. coli in fighting cocks in Southern Thailand. This research is beneficial in preventing the dissemination of E. coli O157:H7 or antimicrobial agent-resistant E. coli in sports animals and humans.

Detection of virulence genes and determination of the antimicrobial susceptibility of Escherichia coli isolates with mastitis in Mashhad, Iran – a short communication

The purpose of this study was to determine the virulence genes and antimicrobial resistance patterns of Escherichia coli isolated from milk samples of cows with bovine mastitis. Forty-seven E. coli isolates from clinical mastitis milk samples, from five dairy farms in Northeast of Iran, were subjected to multiplex PCR to determine virulence genes stx1, stx2, eaeA, hlyA, sta, F4, F17, fliC, and rfbE. In addition, antimicrobial susceptibility was assessed by applying disk diffusion methods. The eaeA and stx1 genes were most frequently detected in 42 (89.3%) and 34 (72.3%) isolates, respectively. However, the least frequent gene was F41 as it was found in only one isolate (2.1%). Furthermore, 9 out of 47 isolates were hlyA positive, and four isolates harbored the sta gene. The antimicrobial susceptibility demonstrated the highest resistance against lincomycin (100%) and neomycin (91.4%). Since these bacteria represent a high-risk pathogen on farms, the emergence of multiple antibiotic-resistant and pathogenic E. coli strains should be of great concern for public health.

Characterization of the Emerging Enteropathogen Escherichia Albertii Isolated from Urine Samples of Patients Attending Sapporo Area Hospitals, Japan

Recently, Escherichia albertii has been identified as a causative agent of diarrhea in humans and is often misidentified as diarrheagenic Escherichia coli (DEC), a lactose-nondegrading bacterium. In this study, we performed biochemical characterization, gene possession status, drug susceptibility testing, and sequencing analysis of the strains detected in urine samples. One urea-degrading strain was detected in terms of biochemical characteristics, but was found to be nonurea-degrading by another method, leading to conflicting results. All target strains possessed the E. albertii-specific gene, the DEC common gene eae, and the E. coli 16S rRNA gene. In the drug susceptibility test, all urine-derived strains were sensitive to tetracycline (TC), whereas the JCM 17328 strain was resistant to TC, suggesting that TC is effective against urine-derived E. albertii strains. In 16S rRNA sequencing analysis, the E. albertii strains were ranked at the top of homology, but not in the top one, making it difficult to differentiate them from other strains. In summary, if a suspected lactose-nondegrading E. coli strain was isolated from a urine sample, it could be differentiated from E. albertii by the presence of E. albertii-specific genes.

Shiga Toxin Subtypes, Serogroups, Phylogroups, RAPD Genotypic Diversity, and Select Virulence Markers of Shiga-Toxigenic Escherichia coli Strains from Goats in Mid-Atlantic US.

Understanding Shiga toxin subtypes in E. coli from reservoir hosts may give insight into their significance as human pathogens. The data also serve as an epidemiological tool for source tracking. We characterized Shiga toxin subtypes in 491 goat E. coli isolates (STEC) from the mid-Atlantic US region (stx1 = 278, stx2 = 213, and stx1/stx2 = 95). Their serogroups, phylogroups, M13RAPD genotypes, eae (intimin), and hly (hemolysin) genes were also evaluated. STEC-positive for stx1 harbored Stx1c (79%), stx1a (21%), and stx a/c (4%). Those positive for Stx2 harbored stx2a (55%) and Stx2b (32%), while stx2a/stx2d and stx2a/stx2b were each 2%. Among the 343 STEC that were serogrouped, 46% (n = 158) belonged to O8, 20% (n = 67) to 076, 12% (n = 42) to O91, 5% (n = 17) to O5, and 5% (n = 18) to O26. Less than 5% belonged to O78, O87, O146, and O103. The hly and eae genes were detected in 48% and 14% of STEC, respectively. Most belonged to phylogroup B1 (73%), followed by D (10%), E (8%), A (4%), B2 (4%), and F (1%). M13RAPD genotyping revealed clonality of 091, O5, O87, O103, and O78 but higher diversity in the O8, O76, and O26 serogroups. These results indicate goat STEC belonged to important non-O157 STEC serogroups, were genomically diverse, and harbored Shiga toxin subtypes associated with severe human disease.

Prevalence and molecular characterization of shiga toxin-producing Escherichia coli in animal source foods and green leafy vegetables.

Shiga toxin-producing Escherichia coli (STEC) has emerged as important enteric foodborne zoonotic pathogens of considerable public health significance worldwide. The aim of this study was to determine the prevalence of the top seven STEC serotypes and to identify these serotypes in samples of animal source foods and vegetables. A total of 294 samples including 84 meat samples, 135 milk and dairy product samples and 75 green leafy vegetable samples were tested. The samples were harvested in mTSB-broth pre-enriched with novobiocin and then were tested by amplifying 16S shiga toxin (stx1/2), and eae genes using multiplex polymerase chain reaction (m-PCR) assay. A total of 260 (88.4%) samples were positive for E. coli and 29 (11.1%) of them were positive for shiga toxin, and eae genes. The positive samples were cultivated on CHROMAgar STEC and the colonies were evaluated for top seven STEC by m-PCR. The top seven STEC serotypes were detected in 27 (93.1%) of the samples: the STEC O111 serotype in 11 (40.7%) beef samples, STEC O45 in 3 (11.1%) chicken, STEC O145 in 6 (22.2%) parsley, 3 (11.1%) lettuce, 1 (3.7%) spinach, and 1 (3.7%) cheese, and STEC O103 in 2 (7.4%) lettuce samples. None of the samples was found positive for STEC O26, O121, and O157 serotypes. This study highlights the fact that the top seven STEC group poses a great risk in terms of food safety and public health in both animal source foods and vegetables.

Identification of Five Serotypes of Enteropathogenic Escherichia coli from Diarrheic Calves and Healthy Cattle in Belgium and Comparative Genomics with Shigatoxigenic E. coli.

Simple SummaryEnteropathogenic Escherichia coli (EPEC) from cattle receive little attention, although some belong to the most notorious O serotypes of attaching/effacing Shigatoxigenic Escherichia coli (AE-STEC) responsible for the uremic and hemolytic syndrome in humans, such as O26. Nevertheless, the O serotypes and virulotypes of the large majority of bovine EPEC remain unidentified. This study aimed to identify five non-classical O serotypes (O123/186, O156, O177, O182, and O183) by a polymerase chain reaction (PCR) among three collections of bovine EPEC from young diarrheic calves, healthy cattle at slaughterhouses, and healthy calves in dairy farms. The virulotypes and sequence types (STs) obtained after the whole genome sequencing of several O156, O177, and O182 bovine EPEC were closely related or identical to the virulotypes and STs of ten bovine and the human AE-STEC of the same O:H serotype. This study allows us to identify more EPEC O serotypes from cattle and to speculate on their evolution. Enteropathogenic Escherichia coli (EPEC) produce attaching/effacing (AE) lesions and cause non-bloody diarrhea in mammals. A minority of bovine EPEC belong to one of the ten classical serotypes of human and bovine AE-STEC. The purpose of this study was to identify five non-classical O serotypes (O123/186, O156, O177, O182, and O183) among bovine EPEC and to characterize their virulence repertoires by whole genome sequencing. Around 40% of the 307 EPEC from 307 diarrheic calves, 368 EPEC from 47 healthy cattle, and 131 EPEC from 36 healthy calves in dairy farms were analyzed. Serotype O177 was the most frequent among EPEC from diarrheic and healthy calves, while the O156 was the most frequent in healthy cattle. The genomic analysis identified different H serotypes, MLSTypes, and/or eae gene subtypes among the O156 and O177 EPEC, while the O182 was homogeneous. The virulence gene profiles of bovine EPEC were closely related to each other and to the profiles of ten bovine and human AE-STEC. These results emphasize the need for additional studies to identify more O:H serotypes of bovine EPEC and to elucidate their origin and evolution of EPEC with regard to AE-STEC belonging to the same O:H serotypes.

Molecular detection of zoonotic pathogens causing gastroenteritis in humans: Salmonella spp., Shigella spp. and Escherichia coli isolated from Rattus species inhabiting chicken farms in North West Province, South Africa.

Rodents are key carriers and reservoirs of various pathogens of public health importance to both human and animal diseases. This research was carried out in order to identify the selected pathogens, namely, Shigella spp., Salmonella spp. and Escherichia coli from rats that inhabit the poultry houses. A total of 154 samples from captured rats were examined for the zoonotic bacterial pathogens, of which 3.3%, 29.9% and 20.7% were harbouring Shigella spp., Salmonella spp., and E. coli, respectively. A total of 14 Shigella isolates expressed presence of ipaH gene, of which eight and five were positive for S. sonnei and S. boydii, respectively. For Salmonella, 68 isolates were positive for invA and other genes including spy with 26 (38%), sdfI 2 (18%), spvC 14 (20%), hilA 28 (41%), misL 43 (63%), orfL 31 (46%) and spiC 38 (56%). For E. coli, the aggR gene was the most prevalent (62 [42%]), followed by the eae gene, which was only detected in 21 (14%) isolates, while stx gene was not detected in any of the samples. This study shows that zoonotic pathogens with virulence genes are circulating in rodents from selected chicken farms in the North West Province of South Africa. Rodents must therefore be regarded as important carriers of zoonotic pathogens that can potentially infect both humans and animals.

Genetic Diversity and Virulence Profiling of Multi-Drug Resistant Escherichia coli of Human, Animal, and Environmental Origins.

Rapid urbanization has increased human-animal interaction and consequently enhanced the chances to acquire zoonotic diseases. The current investigation is focused to uncover the genetic diversity of multidrug-resistant E. coli strains between different ecologies (i.e., humans, livestock, and environment) at the molecular level by employing antimicrobial resistance profiling, virulence genes profiling, and microbial typing approach using ERIC PCR. Based on multiple antibiotic resistance, overall, 19 antibiotic resistance patterns (R1–R19) were observed. Most of the strains (49/60) were detected to have the combinations of stx, eaeA, and hlyA genes and considered STEC/EPEC/EHEC. A total of 18 unique genetic profiles were identified based on ERIC-PCR fingerprints and most of the strains (13) belong to P1 whereas the least number of strains were showing profiles P7 and P8-P11 (one member each profile). The calculated values for Shannon index (H) for human, animal, and environment are 1.70, 1.82, and 1.78, respectively revealing the highest genetic diversity among the E. coli strains of animal origin. The study revealed that drug-resistant pathogenic E. coli strains could be transmitted bidirectionally among the environment, humans, and animals.

Virulence Genes of Pathogenic Escherichia coli in Wild Red Foxes (Vulpes vulpes).

Simple SummaryEscherichia coli is a commensal of the intestinal tract of humans and animals, but some pathotypes can cause severe infections. Enteropathogenic E. coli (EPEC), Shiga toxin-producing E. coli (STEC), and enterohemorrhagic E. coli (EHEC) are the pathotypes most frequently involved in enteric disorders observed in people and domestic animals. Wildlife may harbor and excrete these pathotypes too, therefore, they may be source of infections for humans and domestic animals. Vulpes vulpes seem to be involved in the epidemiology of pathogenic E. coli strains, and thus they could be a relevant threat mainly when they invade human settlements in rural and urban areas.Different pathotypes of Escherichia coli can cause severe diseases in animals and humans. Wildlife may contribute to the circulation of pathogenic pathotypes, including enteropathogenic E. coli (EPEC), Shiga toxin-producing E. coli (STEC), and enterohemorrhagic E. coli (EHEC). This study analyzed 109 DNA samples previously extracted from fecal specimens collected from red foxes (Vulpes vulpes) to detect E. coli virulence genes eaeA, hlyA, stx1, and stx2, that characterize the EPEC, STEC, and EHEC strains. Thirty-one (28.4%) samples were positive for at least one investigated virulence gene: eaeA gene was detected in 21 (19.2%) samples, hlyA in 10 (9.1%), stx1 in 6 (5.5%), and stx2 in 4 (3.6%). Nine DNA samples resulted positive for two or three virulence genes: five (4.6%) samples were positive for eaeA and hlyA genes, two (1.8%) for eaeA and stx1, one (0.9%) for hlyA and stx1, one (0.9%) for eaeA, hlyA and stx2. Red foxes seem to be involved in the epidemiology of these infections and their role could be relevant because they may be source of pathogenic E. coli for other wild animals, as well as domestic animals and humans.

Virulence and antimicrobial-resistance of shiga toxin-producing E. coli (STEC) Isolated from edible shellfish and its public health significance

Shiga toxin-producing E. coli (STEC) are an important cause of foodborne illness in humans with infections ranging from mild non-bloody diarrhea to bloody diarrhea (BD) and hemolytic uremic syndrome (HUS). This study aimed to investigate the distribution of STEC in shellfish from coastal shores of Lake Timsah in Ismailia Governorate, Egypt and its probable hazard to seafood consumers. Samples from the external surface and tissues of shrimp (n = 45), crabs (n = 45), and oysters (n = 45) batches were examined bacteriologically for the presence of STEC and tested for their antibiotic sensitivity. Moreover, occurrence of virulence genes was determined via detection of stx1, stx2 and eaeA genes using PCR. Overall, E. coli and presumptive STEC isolates (from CHROMagar) were identified from the surface (55.6 and 5.9%) and tissues (42.2 and 8.9%) of the examined shellfish batches, respectively. Five STEC isolates had been confirmed and found belonging to O26:H11, O125:H6, O146:H21, and O159 serogroups, those were 4 isolates from tissues of the three shellfish species and one isolate from the crab surface. The STEC isolates were multi-drug resistant, showing complete resistance to; penicillins, amoxycillin/clavulanic acid, colistin, fosfomycin, ceftriaxone, ciprofloxacin, and tetracycline, however, they were sensitive to gentamycin except O159 serogroup. The current study revealed low level of contamination of shellfish from coastal shores of Lake Timsah with STEC, however, it also highlights the extreme level of antimicrobial resistance exhibited by the presumptive and confirmed STEC isolates which is very hazardous for seafood consumers in the study area.