Captive wildlife from India as carriers of Shiga toxin-producing, Enteropathogenic and Enterotoxigenic Escherichia coli

Detection of pathogenic, heteropathogenic and hybrid Escherichia coli strains in psittacines from zoos and breeders in the state of Ceará, Brazil

The current study aimed to detect virulence, hetero-pathogenicity, and hybridization genes in Escherichia coli strains, previously isolated from cloacal swabs in commercial breeding psittacines and zoological collections, via multiplex PCR. A total of 68 strains of E. coli, previously isolated from psittacines in zoos and commercial breeding facilities in Ceará, Brazil, were assessed for the presence of the following genes and/or probes: eae, bfpA (EPEC - Enteropathogenic E. coli), CVD432 (EAEC - Enteroaggregative E. coli); LT gene and ST gene (ETEC - Enterotoxigenic E. coli); ipaH (EIEC - Enteroinvasive E. coli); stx1 and stx2 (STEC - Shiga toxin-producing E. coli); iroN, ompT, hlyF, iss, and iutA (APEC - Avian pathogenic E. coli). Of the 68 E. coli strains analyzed, 61 (98.7 %) were positive for the following genes and/or probes: Stx1 (61/98.7 %), ST gene (54/79.4 %), CVD432 (49/72 %), bfpA (44/64.7 %), eae (42/61.8 %), Stx2 (41/60.3 %), ipaH (34/50 %), LT gene (33/48.5 %), iroN (21/30.9 %), hlyF (11/6.2 %), iss (06/8.8 %) and iutA (06/8.8 %). The following diarrheagenic pathotypes were identified: 66 (97 %) from STEC, 49 (72 %) from EAEC, 35 (52 %) from EIEC, 25 (37 %) from ETEC, and one (1.5 %) from EPEC. Regarding hetero-pathogenicity, 50 (74 %) heterogeneous strains were identified. Positivity for APEC was seen in four (6 %) strains, all characterized as pathogenic hybrids. This study describes significant associations of virulence factors in E. coli strains DEC/DEC and DEC/APEC, which were isolated from psittacines and may be potentially harmful to One Health.

Biofilm-forming antimicrobial-resistant pathogenic Escherichia coli: A one health challenge in Northeast India

This study aimed to investigate the prevalence of Shiga toxin-producing Escherichia coli (STEC), Enteropathogenic E. coli (EPEC), and Enterotoxigenic E. coli (ETEC) in common food animals (cattle, goats, and pigs) reared by tribal communities and smallholder farmers in Northeast India. The isolates were characterized for the presence of virulence genes, extended-spectrum beta-lactamases (ESBL) production, antimicrobial resistance, and biofilm production, and the results were statistically interpreted. In pathotyping 141 E. coli isolates, 10 (7.09%, 95% CI: 3.45%-12.66%) were identified as STEC, 2 (1.42%, 95% CI: 0.17%-5.03%) as atypical-EPEC, and 1 (0.71%, 95% CI: 0.02%-3.89%) as typical-EPEC. None of the isolates were classified as ETEC. Additionally, using the phenotypic combination disc method (ceftazidime with and without clavulanic acid), six isolates (46.1%, 95% CI: 19.22%-74.87%) were determined to be ESBL producers. Among the STEC/EPEC strains, eleven (84.6%, 95% CI: 54.55%-98.08%) and one (7.7%, 95% CI: 0.19%-36.03%) strains were capable of producing strong or moderate biofilms, respectively. PFGE analysis revealed indistinguishable patterns for certain isolates, suggesting clonal relationships. These findings highlight the potential role of food animals reared by tribal communities and smallholder farmers as reservoirs of virulent biofilm-forming E. coli pathotypes, with implications for food contamination and zoonotic infections. Therefore, monitoring these pathogens in food animals is crucial for optimizing public health through one health strategy.

Prevalence and Implications of Shiga Toxin-Producing E. coli in Farm and Wild Ruminants

Shiga-toxin-producing Escherichia coli (STEC) is a food-borne pathogen that causes human gastrointestinal infections across the globe, leading to kidney failure or even death in severe cases. E. coli are commensal members of humans and animals' (cattle, bison, and pigs) guts, however, may acquire Shiga-toxin-encoded phages. This acquisition or colonization by STEC may lead to dysbiosis in the intestinal microbial community of the host. Wildlife and livestock animals can be asymptomatically colonized by STEC, leading to pathogen shedding and transmission. Furthermore, there has been a steady uptick in new STEC variants representing various serotypes. These, along with hybrids of other pathogenic E. coli (UPEC and ExPEC), are of serious concern, especially when they possess enhanced antimicrobial resistance, biofilm formation, etc. Recent studies have reported these in the livestock and food industry with minimal focus on wildlife. Disturbed natural habitats and changing climates are increasingly creating wildlife reservoirs of these pathogens, leading to a rise in zoonotic infections. Therefore, this review comprehensively surveyed studies on STEC prevalence in livestock and wildlife hosts. We further present important microbial and environmental factors contributing to STEC spread as well as infections. Finally, we delve into potential strategies for limiting STEC shedding and transmission.

Phylogenetic Groups, Pathotypes and Antimicrobial Resistance of Escherichia coli Isolated from Western Lowland Gorilla Faeces (Gorilla gorilla gorilla) of Moukalaba-Doudou National Park (MDNP)

(1) Background: Terrestrial mammals in protected areas have been identified as a potential source of antimicrobial-resistant bacteria. Studies on antimicrobial resistance in gorillas have already been conducted. Thus, this study aimed to describe the phylogroups, pathotypes and prevalence of antimicrobial resistance of Escherichia coli isolated from western lowland gorilla's faeces living in MDNP. (2) Materials and Methods: Ninety-six faecal samples were collected from western lowland gorillas (Gorilla gorilla gorilla) during daily monitoring in the MDNP. Sixty-four E. coli isolates were obtained and screened for phylogenetic and pathotype group genes by polymerase chain reaction (PCR) after DNA extraction. In addition, antimicrobial susceptibility was determined by the disk diffusion method on Mueller Hinton agar. (3) Results: Sixty-four (64%) isolates of E. coli were obtained from samples. A high level of resistance to the beta-lactam family, a moderate rate for fluoroquinolone and a low rate for aminoglycoside was obtained. All E. coli isolates were positive in phylogroup PCR with a predominance of A (69% ± 11.36%), followed by B2 (20% ± 19.89%) and B1 (10% ± 8.90%) and low prevalence for D (1% ± 3.04%). In addition, twenty E. coli isolates (31%) were positive for pathotype PCR, such as EPEC (85% ± 10.82%) and EPEC/EHEC (15% ± 5.18%) that were obtained in this study. The majority of these MDR E. coli (DECs) belonged to phylogenetic group A, followed by MDR E. coli (DECs) belonging to group B2. (4) Conclusion: This study is the first description of MDR E. coli (DECs) assigned to phylogroup A in western lowland gorillas from the MDNP in Gabon. Thus, wild gorillas in MDNP could be considered as asymptomatic carriers of potential pathogenic MDR E. coli (DECs) that may present a potential risk to human health.

Detection of novel sequence types and zoonotic transmission potentiality among strains of Shiga toxigenic Escherichia coli (STEC) from dairy calves, animal handlers and associated environments

Shiga toxigenic Escherichia coli (STEC) is one of the most important food-borne zoonotic bacterial pathogens responsible for causing gastrointestinal infections, haemorrhagic colitis and haemolytic uremic syndrome. The present study was aimed to isolate and characterize STEC from neonatal dairy calves, animal handlers and their surrounding environment and to establish the genetic relationship among isolates by multilocus sequence typing (MLST). A total number of 115 samples were collected and processed for the isolation of E. coli. The occurrence rate of E. coli was 92.2% (106/115), of which, 18 were typed as STEC. Antibacterial susceptibility analysis revealed 11 (61.1%) strains as multiple drug-resistant (MDR). MLST analysis has delineated 16 sequence types (STs) including nine novel STs. Among STs, ST58 dominated with three strains and was recovered from the environment and neonatal calves. Strains from neonatal calves and humans showed genetic relatedness with significant bootstrap support values indicative of zoonotic transmission potentiality. Analysis of 211 global isolates belonging to 61 STs indicated predominant STs (ST 21, ST 33 and ST 3416) that can be either host-specific (ST 33 and ST 3416) or can be shared among human and bovine hosts (ST 21). The MLST analysis indicates genetic relatedness among isolates and the results predispose inter-host transmission and zoonotic spread.

Wildlife omnivores and herbivores as a significant vehicle of multidrug-resistant and pathogenic Escherichia coli strains in environment

The phenomenon of resistance of Escherichia coli strains in free-living animals has been constantly expanding in recent years. However, the data are still fragmented and, due to the growing threat to public health, there is a constant need to search for and analyse new reservoirs and indicate their role and importance in the circulation of resistance genes in the environment. Therefore, the target group in this study were free-living non-predatory animals as reservoirs of drug-resistant and potentially virulent E. coli strains. We obtained 70 different isolates, including 71.4% of multidrug-resistant strains. In strains isolated from all species of animals, we determined high resistance to ampicillin (95.7%), tetracycline (64.3%), streptomycin (51.4%) and chloramphenicol (38.6%). Every third of the E. coli-positive individual was a carrier of more than one resistant clone. Moreover, 11.4% of isolates among the resistant strains had the ExPEC, ETEC, or EHEC pathotype. Our study confirmed that not only free-living predatory animals are reservoirs of resistance but also many synanthropic species of herbivores and omnivores contribute substantially to the spread of resistant and virulent E. coli strains.

Pathogenicity of Shiga Toxin Type 2e Escherichia coli in Pig Colibacillosis

Shiga toxin type 2e (Stx2e) Escherichia coli is the causative factor of diarrhea and edema in swine. The aims of this study were to determine the prevalence of Stx2e-producing E. coli isolates and to characterize isolates from clinical cases of pig colibacillosis and healthy swine. During the 11 years of the study (2006–2017), a total of 233 Stx2e-producing isolates were detected−230 out of 2,060 (11.16%) E. coli isolated from diseased pigs and 3 out of 171 (1.75%) from healthy swine. Stx2e-producing isolates were indeed more present in clinical colibacillosis cases than in healthy pigs (p = 0.0002). The predominant serogroup was O139 (79.82%) and the most common fimbrial factor present in these isolates was F18 (177 isolates), followed by F6 (5 isolates). The enterotoxins LTI, STa, and STb were detected in 10.43, 41.73, and 48.26% of the isolates, respectively. The predominant virotypes F18-Stx2e and -STa-STb-Stx2e were similarly present in weaners (33.33 and 35.52%) and finishers (38.30 and 25.53%). Among isolates from diseased pigs, O139 and F18 were the more frequently identified serogroup and virulence factor, respectively. Of the tested 230 Stx2e-producing isolates isolated from diseased pigs, 29 (12.60%) harbored genes encoding ESBL, particularly TEM (79.30%), CTX-M1 (17.20%), and CMY-2 (3.40%). Antimicrobial resistance to tetracycline was the most common characteristic (98.25%), followed by ampicillin (93.91%), cephalotin (90.43%) and trimethoprim/sulfamethoxazole (82.17%). Our results showed that Stx2e-producing E. coli were more frequently associated with clinical forms of colibacillosis, with minimal probability to isolate these isolates from healthy pigs.

Recent Updates on Outbreaks of Shiga Toxin-Producing Escherichia coli and Its Potential Reservoirs

Following infection with certain strains of Shiga toxin-producing Escherichia coli (STEC), particularly enterohemorrhagic ones, patients are at elevated risk for developing life-threatening extraintestinal complications, such as acute renal failure. Hence, these bacteria represent a public health concern in both developed and developing countries. Shiga toxins (Stxs) expressed by STEC are highly cytotoxic class II ribosome-inactivating proteins and primary virulence factors responsible for major clinical signs of Stx-mediated pathogenesis, including bloody diarrhea, hemolytic uremic syndrome (HUS), and neurological complications. Ruminant animals are thought to serve as critical environmental reservoirs of Stx-producing Escherichia coli (STEC), but other emerging or arising reservoirs of the toxin-producing bacteria have been overlooked. In particular, a number of new animal species from wildlife and aquaculture industries have recently been identified as unexpected reservoir or spillover hosts of STEC. Here, we summarize recent findings about reservoirs of STEC and review outbreaks of these bacteria both within and outside the United States. A better understanding of environmental transmission to humans will facilitate the development of novel strategies for preventing zoonotic STEC infection.

Pathotypes and Antimicrobial Susceptibility of Escherichia Coli Isolated from Wild Boar (Sus scrofa) in Tuscany

Wild boar are among the most widespread wild mammals in Europe. Although this species can act as a reservoir for different pathogens, data about its role as a carrier of pathogenic and antimicrobial-resistant Escherichia coli are still scarce. The aim of this study was to evaluate the occurrence of antimicrobial-resistant and pathogenic Escherichia coli in wild boar in the Tuscany region of Italy. During the hunting season of 2018-2019, E. coli was isolated from 175 of 200 animals and subjected to antimicrobial resistance tests and PCR for detection of resistance and virulence factor genes. The highest resistance rates were against cephalothin (94.3%), amoxicillin-clavulanic acid (87.4%), ampicillin (68.6%), and tetracycline (44.6%). The most detected resistance genes were blaCMY-2 (54.3%), sul1 (38.9%), sul2 (30.9%), and tetG (24.6%). Concerning genes encoding virulence factors, 55 of 175 isolates (31.4%) were negative for all tested genes. The most detected genes were hlyA (47.4%), astA (29.1%), stx2 (24.6%), eaeA (17.1%), and stx1 (11.4%). E. coli was classified as Shiga toxin-producing E. coli (STEC) (21.7%), enterohemorrhagic E. coli (EHEC) (6.3%), enteroaggregative E. coli (EAEC) (5.1%), and atypical enteropathogenic E. coli (aEPEC) (3.4%). Enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and typical enteropathogenic E. coli (tEPEC) were not detected. Our results show that wild boars could carry pathogenic and antimicrobial-resistant E. coli, representing a possible reservoir of domestic animal and human pathogens.

Captive Green Iguana Carries Diarrheagenic Escherichia coli Pathotypes

The green iguana appears to be a carrier for bacteria causing gastrointestinal infections in humans. The presence of diarrheagenic E. coli (DEC) pathotypes, however, has not been studied in this reptile. The aim of the current work was to investigate the prevalence of DEC in the intestines of 240 captive green iguanas, their phylogenetic groups, and the antibiotic susceptibility profile. E. coli strains were isolated from 41.7% (N = 100/240) of the intestinal content of green iguanas. DEC strains was identified in 25.9% of the screened population and were detected in the majority (62%, p = 0.009) of those reptiles carrying E. coli strains. Among DEC strains, STEC strains carrying the stx1 gene were the most prevalent pathotype isolated (38.7%), followed by EAEC and ETEC (27.4% each). Genetic markers of DEC strains belonging to the EHEC pathotype were not detected. More than a half of DEC strains were classified into the Clade I-II phylogroup (64.5%), followed by the phylogroup A (14.5%). The antibiotic susceptibility method demonstrated that a high proportion of DEC strains were resistance, or non-susceptible, to carbenicillin, amikacin, and ampicillin. We conclude that the green iguana kept in captivity is a carrier of DEC strains bearing resistance to first-line antibiotics, including penicillins. Given the increase presence of the green iguana in Latin American households, these reptiles represent a potential source of transmission to susceptible humans and therefore a potential source of gastrointestinal disease.