Confirmational identification of Escherichia coli, a comparison of genotypic and phenotypic assays for glutamate decarboxylase and beta-D-glucuronidase

Variations in antimicrobial resistance genes present in the rectal faeces of seals in Scottish and Liverpool Bay coastal waters

Antibiotic resistance genes originating from human activity are considered important environmental pollutants. Wildlife species can act as sentinels for coastal environmental contamination and in this study we used qPCR array technology to investigate the variety and abundance of antimicrobial resistance genes (ARGs), mobile genetic elements (MGEs) and integrons circulating within seal populations both near to and far from large human populations located around the Scottish and northwest English coast. Rectal swabs were taken from 50 live grey seals and nine live harbour seals. Nucleic acids were stabilised upon collection, enabling extraction of sufficient quality and quantity DNA for downstream analysis. 78 ARG targets, including genes of clinical significance, four MGE targets and three integron targets were used to monitor genes within 22 sample pools. 30 ARGs were detected, as well as the integrons intl1 and intl2 and tnpA transposase. Four β-lactam, nine tetracycline, two phenicol, one trimethoprim, three aminoglycoside and ten multidrug resistance genes were detected as well as mcr-1 which confers resistance to colistin, an important drug of last resort. No sulphonamide, vancomycin, macrolide, lincosamide or streptogramin B (MLSB) resistance genes were detected. Resistance genes were detected in all sites but the highest number of ARGs (n = 29) was detected in samples derived from grey seals on the Isle of May, Scotland during the breeding season, and these genes also had the highest average abundance in relation to the 16S rRNA gene. This pilot study demonstrates the effectiveness of a culture-independent workflow for global analysis of ARGs within the microbiota of live, free-ranging, wild animals from habitats close to and remote from human habitation, and highlights seals as a valuable indicator species for monitoring the presence, abundance and land-sea transference of resistance genes within and between ecosystems.

High Genetic Diversity in Third-Generation Cephalosporin-Resistant Escherichia coli in Wastewater Systems of Schleswig-Holstein

The spread of multidrug-resistant bacteria from humans or livestock is a critical issue. However, the epidemiology of resistant pathogens across wastewater pathways is poorly understood. Therefore, we performed a detailed comparison of third-generation cephalosporin-resistant Escherichia coli (3GCREC) from wastewater treatment plants (WWTPs) to analyze dissemination pathways. A total of 172 3GCREC isolated from four WWTPs were characterized via whole genome sequencing. Clonal relatedness was determined using multi-locus sequence typing (MLST) and core genome MLST. Resistance genotypes and plasmid replicons were determined. A total of 68 MLST sequence types were observed with 28 closely related clusters. Resistance genes to eight antibiotic classes were detected. In fluoroquinolone-resistant isolates, resistance was associated with three-or-more point mutations in target genes. Typing revealed high genetic diversity with only a few clonal lineages present in all WWTPs. The distribution paths of individual lines could only be traced in exceptional cases with a lack of enrichment of certain lineages. Varying resistance genes and plasmids, as well as fluoroquinolone resistance-associated point mutations in individual isolates, further corroborated the high diversity of 3GCREC in WWTPs. In total, we observed high diversity of 3GCREC inside the tested WWTPs with proof of resistant strains being released into the environment even after treatment processes.

Association between bacterial pathogenicity, endometrial histological changes and clinical prognosis in canine pyometra

Despite the high frequency and clinical relevance of canine pyometra, its pathogenesis remains poorly understood. In this study, the clinical data, histopathological alterations, and microbiological findings of 39 dogs with pyometra were analyzed to assess possible associations. The mean age of the affected animals was 9.6 ± 3.8 years; 76.3 % (29/38) had open cervix pyometra, 88 % (22/25) had tachypnea, 71 % (27/38) had anorexia, and 60.5 % (23/38) had leukocytosis. Histopathological analysis revealed that 66.5 % (26/39) of the uteri had a high degree of inflammation (score 4). Third-degree hyperplasia of the endometrial epithelium (72 %, 28/39) and intralesional or intrauterine bacteria (66.5 %, 26/39) were identified in most animals. Bacterial isolates were obtained from 82 % (32/39) of the uterine contents and five bacterial species were identified. Escherichia coli, classified in phylogroup B2, is associated with virulent adhesion genes (fimH, focG, and papC), and serum resistance (traT) was the most common isolate. There was an association between the detection of papC in E. coli isolates and higher necrosis scores. Additionally, the necrosis score was positively associated with the length of hospitalization, with each point increase in the necrosis score leading to two more days of hospitalization. These results suggest that papC-positive E. coli play an important role in the severity of pyometra in dogs. The present study revealed the possibility of using this virulence gene to better understand the prognosis of the disease in an affected animal.

Characterization of ESBL/AmpC-producing extraintestinal Escherichia coli (ExPEC) in dogs treated at a veterinary hospital in Brazil

The clinical aspects and lineages involved in Extraintestinal pathogenic Escherichia coli (ExPEC) infections in dogs remain largely unknown. In this study, we investigated the antimicrobial resistance and molecular structures of ExPECs isolated from infected dogs in Brazil. Samples were obtained from dogs (n = 42) with suspected extraintestinal bacterial infections. Phylogroup B2 was predominant (65.1%). No association was observed between the site of infection, phylogroups, or virulence factors. Almost half of the isolates (44.2%) were MDR, and 20.9% were extended-spectrum β-lactamase (ESBL)-positive. E. coli isolates that were resistant to fluoroquinolones (27.9%) were more likely to be MDR. The CTX-M-15 enzyme was predominant among the ESBL-producing strains, and seven sequence types were identified, including the high-risk clones ST44 and ST131. Single SNPs analysis confirmed the presence of two clonal transmissions. The present study showed a high frequency of ExPECs from phylogroup B2 infecting various sites and a high frequency of ESBL-producing strains that included STs frequently associated with human infection. This study also confirmed the nosocomial transmission of ESBL-producing E. coli, highlighting the need for further studies on the prevention and diagnosis of nosocomial infections in veterinary settings.

Transmission of Escherichia coli Causing Pyometra between Two Female Dogs

Despite its clinical relevance, the pathogenesis of canine pyometra remains poorly understood. To date, it is recognized as a non-transmissible infectious disease. In this study, the simultaneous occurrence of pyometra and Escherichia coli in two cohabitant female dogs underwent in-depth investigation due to the hypothesis of transmission between these animals. Two 5-year-old Chow Chow dogs (namely, dogs 23 and 24-D23 and D24) were referred to a veterinary hospital with suspected pyometra. Both animals showed prostration, anorexia, and purulent vulvar discharge over a 1-week period. After ovariohysterectomy, uterine tissue, uterine contents, and rectal swabs were collected for histopathological and microbiological analysis. Uterine histology demonstrated purulent material and multifocal necrosis with endometrial ulceration, and a morphological diagnosis of pyometra was confirmed. Furthermore, E. coli from the same phylogroup (B2) and positive for the same virulence factors with the same antimicrobial susceptibility profile was isolated from the uterine contents of both dogs and the rectum of D23. Conversely, the E. coli strains recovered from D24 differed in phylogroup (one isolate), virulence factors (all three isolates), and antimicrobial susceptibility (all three isolates). Enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) suggested that all isolates from the uterine content of both dogs and the rectal swab of D23 were 100% the same, but different from all isolates in the rectal swab of D24. One isolate from the uterine content of each animal as well as rectal swabs were subjected to whole-genome sequencing (WGS). Both whole-genome multilocus sequence typing(wgMLST) and single-nucleotide polymorphism (SNP) analysis supported the hypothesis that the isolates from the uterine content of both animals and the rectal swab of D23 were clonal. Taken together, these clinical features, pathology, microbiology, and molecular findings suggest, to the best of our knowledge, the first transmission of E. coli associated with pyometra between two animals. These results could impact the management of sites where several females cohabit in the same local area such as kennels.

Clonal Dissemination of Extended-Spectrum Cephalosporin-Resistant Enterobacterales between Dogs and Humans in Households and Animal Shelters of Romania

Faecal carriage of extended-spectrum cephalosporin-resistant (ESC-R) Enterobacterales in healthy pets is a concerning issue. This study aimed to determine the prevalence, genetic background, and potential for interspecies transmission of these bacteria between dogs and humans within the same household (HH) or shelter environment in Romania. Faecal samples (n = 263) collected from healthy dogs (n = 102), their owners (n = 32), as well as dogs (n = 110) and staff (n = 19) from dog shelters, were screened for ESC-R carriage. Clonal relatedness of canine and human Escherichia coli isolates was established using Fourier Transform Infrared Spectroscopy (FTIR), followed by Illumina WGS of selected isolates. The highest prevalence of ESC-R Enterobacterales faecal carriage was identified in staff working at dog shelters (78.9%), followed by dogs from households (44.11%), dog owners (43.7%), and dogs from shelters (27%). FTIR identified 15 clusters of closely related E. coli isolates, including dog and human isolates from the same environment. Co-carriage of ESC-R isolates in both the dog and owner was identified in 12 HHs (37.5%), with two HHs (6%) having both the owner and dog carrying isolates with identical FTIR spectra, phylogroup, resistance genes, and Inc plasmids. Major ExPEC lineages such as ST127, ST10, ST155, and ST88 were detected in human and dog isolates. Our study revealed a high prevalence of faecal ESC-R E. coli carriage in both dogs and humans from Romanian households and shelters, where bidirectional clonal transmission between humans and dogs is likely. Furthermore, we identified ESC-R Enterobacterales co-carriage in people and dogs sharing the same environment using FTIR, demonstrating its value in AMR surveillance for humans and animals.

Investigation of In Vitro Susceptibility and Resistance Mechanisms in Skin Pathogens: Perspectives for Fluoroquinolone Therapy in Canine Pyoderma

Fluoroquinolones (FQ) are commonly used in dogs with bacterial skin infections. Their use as first choice, along with the increased incidence of FQ-resistance, represents a risk to animal and public health. Our study determined minimum inhibitory (MIC) and bactericidal (MBC) concentrations of five FQs in Staphylococcus aureus, Staphylococcus pseudintermedius, and Escherichia coli, together with FQ-resistance mechanisms. MICs, efflux pump (EP) overexpression and MBCs were measured in 249 skin infection isolates following CLSI guidelines (CLSI VET01-A4, CLSI M26-A). Chromosomal and plasmid-mediated resistance genes were investigated after DNA extraction and sequencing. FQ-resistance was detected in 10% of methicillin-susceptible (MS), 90% of methicillin-resistant (MR) staphylococci and in 36% of E. coli. Bactericidal effect was observed except in 50% of MRSA/P for ciprofloxacin and in 20% of MRSPs for enrofloxacin. Highest MICs were associated with double mutation in gyrA (Ser83Leu + Asp87Asn), efflux pumps and three PMQR genes in E. coli, and grlA (Ser80Phe + Glu84Lys) in S. aureus. EP overexpression was high among E. coli (96%), low in S. aureus (1%) and absent in S. pseudintermedius. Pradofloxacin and moxifloxacin showed low MICs with bactericidal effect. Since in vitro FQ resistance was associated with MR, FQ use should be prudently guided by susceptibility testing.

Longitudinal Study Detects the Co-Carriage of ESBL and mcr-1 and -4 Genes in Escherichia coli Strains in a Portuguese Farrow-to-Finish Swine Herd

Cephalosporins and polymyxins are employed in antimicrobial protocols to control and treat neonatal infections and post-weaning diarrhoea in swine operations. We conducted a longitudinal study to evaluate the colonization and transmission of antibiotic–resistant Escherichia coli in sows and their piglets in a farrow-to-finish operation, focusing on characterization of Extended Spectrum Beta-Lactamase (ESBL) and mcr genes, virulence traits and genetic relatedness. A total of 293 E. coli isolates were obtained from faecal samples collected in five time points. At birth blaCTX-M-1group cluster was detected in E. coli isolates from 9 sows and 49 piglets (73.41%), while in the following four’ piglets sampling moments it was detected in 91.8%, 57.6%, 71.4% and 97.4%. The gene mcr-1 was detected in E. coli from one sow and from three piglets from different litters at birth and increased in the first weeks of piglet life (68.85%, 100%, 90% and 8.1%). A new mcr-4 allele, mcr-4.7, was identified in 3.28%, 28.57%, 7.5% of E. coli isolates. Most mcr-positive E. coli isolates (96,7%) carried blaCTX-M-1Group genes and 93,33% carried both mcr-4 and mcr-1. CTX-M-1 and CTX-M-32 were the most predominant ESBLs. Plasmids belonged to IncI1, IncF and IncN groups. Most isolates belong to phylogenetic group B1; PAI IV536 marker was detected in nine isolates. The strains were kept in the different stages of the piglets’ life. The use of ceftiofur and colistin may explain the high prevalence and co-selection of blaCTX-M-1Group and mcr-1 and/or -4 genes, contributing to the maintenance of resistant and virulent isolates throughout the pig life cycle that may reach the food chain.

Characterization of Escherichia coli in Dogs with Pyometra and the Influence of Diet on the Intestinal Colonization of Extraintestinal Pathogenic E. coli (ExPEC)

Despite its high frequency and clinical relevance, the pathogenesis of canine pyometra remains poorly understood. The most accepted hypothesis is that bacteria involved ascend from the intestinal tract, causing the uterine infection. Extraintestinal pathogenic Escherichia coli (ExPEC) is the most frequent pathogen in canine pyometra, accounting for 57–100% of cases. The aim of the present study was to determine the frequency of phylogenetic groups and virulence factors in E. coli strains isolated from the uterine and rectal swabs of bitches with pyometra (n = 72) and from rectal swabs from healthy bitches fed commercial dry feed (n = 53) or a raw meat-based diet (RMBD; n = 38). A total of 512 strains of E. coli were isolated and divided into five categories according to the origin of the sample: 120 isolates from the uterine content of dogs with E. coli pyometra, 102 from the feces of bitches with E. coli pyometra, 75 from the feces of bitches without E. coli pyometra, 130 feces samples from healthy dogs fed commercial feed, and 85 feces samples from healthy dogs fed a raw meat-based diet. E. coli strains belonging to the B2 phylogroup and positive for virulence factor genes associated with adhesion (fimbriae type P [papC]) and production of toxins (α-hemolysin [hlyA] and uropathogenic specific protein [usp]) predominated in the uterine content and rectal swabs of bitches with E. coli pyometra. Interestingly, a lower growth rate of E. coli from the B2 phylogroup was observed in dogs fed a RMBD than in those fed commercial dry feed. The present study suggests that intestinal colonization by certain types of E. coli could be a risk factor for the occurrence of E. coli pyometra in bitches and that diet can influence intestinal colonization by such strains.

ESBL/pAmpC-Producing Escherichia coli Causing Urinary Tract Infections in Non-Related Companion Animals and Humans

Urinary tract infections (UTI) caused by Escherichia coli are frequently diagnosed in humans and companion animals. Extended-spectrum beta-lactamase (ESBL)- and cephalosporinase (pAmpC)-producing Escherichia coli are worldwide-disseminated and frequently multidrug-resistant, hence leading to treatment failure and public health concerns. This study aimed to characterize and compare ESBL/pAmpC-producing E. coli strains causing community-acquired UTI in companion animals and non-related humans. Third-generation cephalosporin (3GC)-resistant E. coli (companion animals n = 35; humans n = 85) isolated from patients with UTI were tested against 14 antimicrobials following CLSI guidelines. PCR-based assays were used to detect the major E. coli phylogenetic groups, pathogenicity associated-islands (PAIs), virulence genes, and ESBLs/pAmpC resistance genes. ESBL/pAmpC-producing E. coli isolates were typed by multi-locus sequence typing (MLST) and PCR. E. coli strains from companion animals and humans shared two MDR high-risk clonal lineages: ST131 and ST648. To the best of our knowledge, this study reports the first description of E. coli ST131 clade C1-M27 and the clonal lineage ST131 clade A in humans with community-acquired UTI in Portugal. Considering that companion animals with UTI are generally treated at home by the owners, measures should be implemented to avoid the spread of multidrug-resistant high-risk clones to humans and their household environment.

Fecal Shedding of Multidrug Resistant Escherichia coli Isolates in Dogs Fed with Raw Meat-Based Diets in Brazil

The practice of feeding dogs raw meat-based diets (RMBDs) is growing in several countries, and the risks associated with the ingestion of pathogenic and antimicrobial-resistant Escherichia coli in dogs fed these diets are largely unknown. We characterized E. coli strains isolated from dogs fed either an RMBD or a conventional dry feed, according to the phylogroup, virulence genes, and antimicrobial susceptibility profiles of the bacteria. Two hundred and sixteen E. coli strains were isolated. Dogs fed RMBDs shed E. coli strains from the phylogroup E more frequently and were positive for the E. coli heat-stable enterotoxin 1-encoding gene. Isolates from RMBD-fed dogs were also frequently positive for multidrug-resistant E. coli isolates including extended-spectrum beta-lactamase (ESBL) producers. Whole-genome sequencing of seven ESBL-producing E. coli strains revealed that they predominantly harbored blaCTX-M-55, and two strains were also positive for the colistin-resistant gene mcr-1. These results suggest that feeding an RMBD can affect the dog’s microbiota, change the frequency of certain phylogroups, and increase the shedding of diarrheagenic E. coli. Also, feeding an RMBD seemed to be linked with the fecal shedding of multidrug-resistant E. coli, including the spread of strains harboring mobilizable colistin resistance and ESBL genes. This finding is of concern for both animal and human health.

UK dogs eating raw meat diets have higher risk of Salmonella and antimicrobial-resistant Escherichia coli faecal carriage

Objectives

To compare detection of Salmonella species and antimicrobial‐resistant Escherichia coli in the faeces of dogs eating raw meat or non‐raw diets and examine risk factors for their carriage.

Materials and Methods

Canine faecal samples (raw fed n=114; non‐raw fed n=76) were collected from May to July 2015 from across the UK. Enrichment and selective culture and biochemical and PCR assays were used to identify isolates. Escherichia coli underwent susceptibility testing to a range of antimicrobials, including third‐generation cephalosporins; PCR assays were used to detect antimicrobial‐resistant genes. Questionnaires were used to collect data on independent variables as risks for antimicrobial‐resistant (resistant to ≥1 tested antimicrobial), multi‐drug‐resistant (resistant to ≥3 antimicrobial classes) and third‐generation cephalosporin resistant Escherichia coli.

Results

Antimicrobial‐resistant, multi‐drug‐resistant and third‐generation cephalosporin resistant Escherichia coli were significantly more likely to be detected in raw fed (54, 25 and 31%, respectively) compared to non‐raw fed (17, 4 and 4%, respectively) dogs; Salmonella species were detected in eight (4%) raw fed dogs only.

Clinical Significance

Raw fed dogs may be a source of Salmonella species and Escherichia coli, resistant to highest priority critically important antimicrobials, representing a potential animal welfare and public health issue. Owners should be aware of the risks, especially households with members, both human and canine, who are very young, elderly or immunocompromised.

Prevalence, diversity and genetic structure of Escherichia coli isolates from septic tanks

The present study investigated the diversity and genetic structure of Escherichia coli isolates from 100 septic tanks in the Canberra region, Australia. The physicochemical characteristics of the septic tanks were determined to examine the extent to which environmental factors might influence E. coli prevalence, diversity and population structure. The results of this study indicated that the temperature of the septic tank could explain some of the variation observed in the number of E. coli isolates recovered per septic tank, whereas pH was an important driver of E. coli diversity. Conductivity, pH and household size had a significant impact on E. coli population structure, and household size significantly affected the probability of detecting human-associated E. coli lineages [sequence types (STs) 69, 73, 95 and 131] in septic tanks. Phylogroup A and B1 strains were not randomly distributed among septic tanks, and the strong negative association between them may indicate intraspecific competition. The findings of this study suggest that the combination of environmental factors and intraspecific interactions may influence the distribution and genetic structure of E. coli in the environment.

Simultaneous Detection of Four Main Foodborne Pathogens in Ready-to-Eat Food by Using a Simple and Rapid Multiplex PCR (mPCR) Assay

The increasing consumption of organic or ready-to-eat food may cause serious foodborne disease outbreaks. Developing microbiological culture for detection of food-borne pathogens is time-consuming, expensive, and laborious. Thus, alternative methods such as polymerase chain reaction (PCR) are usually employed for outbreaks investigation. In this work, we aimed to develop a rapid and simple protocol for the simultaneous detection of Escherichia coli (E coli), Listeria monocytogenes (L. monocytogenes), Staphylococcus aureus (S. aureus) and Salmonella enterica (S. enterica), by the combination of an enrichment step in a single culture broth and a multiplex PCR (mPCR) assay. The effectiveness of several enrichment media was assessed by culture and PCR. Buffered peptone water (BPW) was selected as the optimum one. Then, mPCR conditions were optimized and applied both to pure co-cultures and artificially inoculated food samples (organic lettuce and minced meat). In the culture medium inoculated at 10⁰ CFU/mL, mPCR was able to detect the four microorganisms. When performed on artificially food samples, the mPCR assy was able to detect E. coli, S. enterica, and L. monocytogenes. In conclusion, BPW broth can effectively support the simultaneous growth of E. coli, S. aureus, L. monocytogenes, and S. enterica and could be, thus, used prior to a mPCR detection assay in ready-to-eat food, thereby considerably reducing the time, efforts and costs of analyzes.

Enteric Organisms Detected in Feces of Dogs With Bloody Diarrhea: 45 Cases

Bloody diarrhea is a common condition in dogs, but studies evaluating the enteropathogens involved specifically in adult dogs are scarce. In the present study, stool samples from 45 adult dogs with bloody diarrhea were evaluated for the four enteric organisms mainly reported in these cases: canine parvovirus type 2 (CPV-2), Clostridioides difficile, Clostridium perfringens, and Salmonella spp. In addition, the samples were also tested for coronavirus, rotavirus, Giardia spp., and Escherichia coli pathotypes to provide a better understanding of possible co-occurrence. Vaccination status, diet, and clinical outcome were also obtained when available. CPV-2b was identified in 17 dogs (37.8%), being the most frequent cause of bloody diarrhea, including completely vaccinated adult dogs. Toxigenic C. difficile and C. perfringens netF⁺ were detected in 6 (13.3%) and 5 (11.1%) dogs, in some cases in a co-occurrence with other enteric organisms. Three fatal cases of salmonellosis were identified in dogs fed a raw meat-based diet, raising the risks associated with this increasing practice.

Prevalence of qnrS-positive Escherichia coli from chicken in Thailand and possible co-selection of isolates with plasmids carrying qnrS and trimethoprim-resistance genes under farm use of trimethoprim

One hundred and twenty chicken samples from feces (n = 80), the carcass surface at slaughter at 2 meat chicken farms (n = 20), and retail chicken meat from 5 markets (n = 20) collected during 2018 and 2019 were examined for the prevalence of plasmid-mediated quinolone resistance (PMQR) in Escherichia coli. We detected qnrS-positive E. coli in a total of 74 samples from feces (n = 59), the carcass surface (n = 7), and retail meat (n = 8). These 74 qnrS-positive isolates were tested for antimicrobial susceptibility to determine the minimum inhibitory concentrations (MICs) of certain antimicrobials and genetically characterized. Ampicillin-resistance accounted for 71 of the 74 isolates (96%), followed by resistance to oxytetracycline (57/74; 77%), enrofloxacin (ERFX) (56/74; 76%), sulfisoxazole (SUL) (56/74; 76%), trimethoprim (TMP) (49/74; 66%), and dihydrostreptomycin (48/74; 65%). All farm-borne SUL- and TMP-resistant isolates except one were obtained from samples from farm A where a combination of sulfadiazine and TMP was administered to the chickens. Concentrations of ERFX at which 50 and 90% of isolates were inhibited were 2 μg/mL and 32 μg/mL, respectively. Diverse pulsed-field gel electrophoresis (PFGE) patterns of XbaI-digested genomic DNA were observed in the qnrS-positive isolates from fecal samples. Several isolates from feces and the carcass surface had identical XbaI-digested PFGE patterns. S1-nuclease PFGE and Southern blot analysis demonstrated that 7 of 11 dfrA13-positive fecal isolates carried both the qnrS and dfrA13 genes on the same plasmid, and 2 of 3 dfrA1-positive isolates similarly carried both qnrS and dfrA1 on the same plasmid, although the PFGE patterns of XbaI-digested genomic DNA of the isolates were different. These results suggest that the qnrS gene is prevalent in chicken farms via horizontal transfer of plasmids and may partly be co-selected under the use of TMP.

Temporal, Spatial, and Genomic Analyses of Enterobacteriaceae Clinical Antimicrobial Resistance in Companion Animals Reveals Phenotypes and Genotypes of One Health Concern

Background

Antimicrobial resistance (AMR) is a globally important one health threat. The impact of resistant infections on companion animals, and the potential public health implications of such infections, has not been widely explored, largely due to an absence of structured population-level data.

Objectives

We aimed to efficiently capture and repurpose antimicrobial susceptibility test (AST) results data from several veterinary diagnostic laboratories (VDLs) across the United Kingdom to facilitate national companion animal clinical AMR surveillance. We also sought to harness and genotypically characterize isolates of potential AMR importance from these laboratories.

Methods

We summarized AST results for 29,330 canine and 8,279 feline Enterobacteriaceae isolates originating from companion animal clinical practice, performed between April 2016 and July 2018 from four VDLs, with submissions from 2,237 United Kingdom veterinary practice sites.

Results

Escherichia coli (E. coli) was the most commonly isolated Enterobacteriaceae in dogs (69.4% of AST results, 95% confidence interval, CI, 68.7-70.0) and cats (90.5%, CI 89.8-91.3). Multi-drug resistance was reported in 14.1% (CI 13.5-14.8) of canine and 12.0% (CI 11.1-12.9) of feline E. coli isolates. Referral practices were associated with increased E. coli 3rd generation ≤ cephalosporin resistance odds (dogs: odds ratio 2.0, CI 1.2-3.4). We selected 95 E. coli isolates for whole genome analyses, of which seven belonged to sequence type 131, also carrying the plasmid-associated extended spectrum β-lactamase gene bla _{CTX-M- 15}. The plasmid-mediated colistin resistance gene mcr-9 was also identified for the first time in companion animals.

Conclusions

Linking clinical AMR data with genotypic characterization represents an efficient means of identifying important resistance trends in companion animals on a national scale.

Unveiling the Virulent Genotype and Unusual Biochemical Behavior of Escherichia coli ST59

Extraintestinal pathogenic Escherichia coli (ExPEC) is a leading cause of human and animal infections worldwide. The utilization of selective and differential media to facilitate the isolation and identification of E. coli from complex samples, such as water, food, sediment, and gut tissue, is common in epidemiological studies. During a surveillance study, we identified an E. coli strain isolated from human blood culture that displayed atypical light cream-colored colonies in chromogenic agar and was unable to produce β-glucuronidase and β-galactosidase in biochemical tests. Genomic analysis showed that the strain belongs to sequence type 59 (ST59) and phylogroup F. The evaluation in silico of 104 available sequenced lineages of ST59 complex showed that most of them belong to serotype O1:K1:H7, are β-glucuronidase negative, and harbor a virulent genotype associated with the presence of important virulence markers such as pap, kpsE, chuA, fyuA, and yfcV. Most of them were isolated from extraintestinal human infections in diverse countries worldwide and could be clustered/subgrouped based on papAF allele analysis. Considering that all analyzed strains harbor a virulent genotype and most do not exhibit biochemical behavior typical of E. coli, we report that they could be misclassified or underestimated, especially in epidemiological studies where the screening criteria rely only on typical biochemical phenotypes, as happens when chromogenic media are used. IMPORTANCE The use of selective and differential media guides presumptive bacterial identification based on specific metabolic traits that are specific to each bacterial species. When a bacterial specimen displays an unusual phenotype in these media, this characteristic may lead to bacterial misidentification or a significant delay in its identification, putting a patient at risk depending on the infection type. In the present work, we describe a virulent E. coli sequence type (ST59) that does not produce beta-glucuronidase (GUS negative), production of which is the metabolic trait widely used for E. coli presumptive identification in diverse differential media. The recognition of this unusual metabolic trait may help in the proper identification of ST59 isolates, the identification of their reservoir, and the evaluation of the frequency of these pathogens in places where automatic identification methods are not available.

Multidrug resistance IncC plasmid carrying blaCMY-97 in Shiga toxin-producing Escherichia coli ST215-H54 of ovine origin

CMY-type β-lactamases are the most reported plasmid-mediated AmpC (pAmpC), with the CMY-2-like group being the most clinically relevant described in Escherichia coli at human-animal-environment interface. Shiga toxin-producing E. coli (STEC) lineages are zoonotic pathogens commonly reported causing serious clinical conditions in humans, including severe diarrheagenic diseases. Therefore, this study aimed to investigate a multidrug-resistant (MDR) STEC isolate (A313) recovered from a healthy sheep and carrying mobile bla_CMY-97, that encodes a pAmpC belonging to the CMY-2-like group. The A313 isolate exhibited a MDR profile to clinically relevant antimicrobials (i.e., cephalosporins, aminoglycosides, and fluoroquinolones), but reduced susceptibility to extended-spectrum cephalosporins and aztreonam. Besides, virulence genes (stx2, gad and iutA) were detected in A313, which belonged to ST215/CC10 and phylogenetic group A, whereas the fimH54 was identified. The bla_CMY-97 gene and other antimicrobial resistance determinants [aph(6)-Id, aph(3″)-Ib, aac(3)-IId, aadA5, floR, tetA, sul1, and sul2], as well as genes encoding tolerance to mercury (merRTPCADE), were harbored by an IncC plasmid (named pA313-CMY-97, ~ 176 kb). A novel genetic context of bla_CMY-2-like, in which a 208-bp ISEcp1 was truncated by an IS26 in the opposite orientation upstream of the bla_CMY-97 gene (IS26-∆ISEcp1-bla_CMY-97-blc-sugE-encR), was also identified in pA313-CMY-97. To the best of our knowledge, this is the first report on the acquisition of bla_CMY-97 into a plasmid. Therefore, we reported ovine as reservoir of clinically relevant MDR bacteria carrying mobile bla_CMY-97 with potential for zoonotic transmission.

Characterization of antibiotic resistance in Escherichia coli isolates from Black-headed gulls (Larus ridibundus) present in the city of Novi Sad, Serbia

Despite common resistance to antimicrobials in Escherichia coli isolates from farm animals in Serbia, no data are currently accessible on its occurrence in E. coli isolated from gulls. Therefore, 67 cloacal swabs and 70 fecal samples from black-headed gulls were investigated for the presence of antibiotic-resistant E. coli isolates. Ninety-nine isolates were obtained during the study. Resistotyping and resistance gene typing has shown that 44 isolates harbor resistance to one or more antibiotics. Multidrug resistance was detected in 24 E. coli isolates. Ten isolates were resistant to extended-spectrum cephalosporin antibiotics and were studied in detail including virulence gene typing, phylogenetic and multilocus sequence typing, and mating. These ten isolates belonged to phylogenetic groups B2 (five isolates), D (four isolates) and B1 (one isolate). Five different sequence types (ST38, ST2307, ST224, ST162 and ST34) were detected in E. coli isolates with AmpC phenotype and genotype. One isolate carried the Inc I2/FIB replicon type plasmid with the bla_CTX-M-1 gene. Nine isolates had bla_CMY-2 genes, which were detected on conjugative plasmids in seven isolates. The virulence genes hly, iroN, iss, ompT and cvaC were detected in one transconjugant. Ten isolates were found to be resistant to ciprofloxacin, whose MIC ranged from 4 to 32 mg/L. Genotyping revealed single or double mutations in the quinolone resistance determining region (QRDR) of the gyrA or gyrA, parC and parE genes, respectively. So, Black-headed gulls from Serbia may be colonized by multidrug-resistant E. coli, some of which are resistant to critically important antibiotics in medicine.

Plasmid Replicon Typing of Antibiotic-Resistant Escherichia coli From Clams and Marine Sediments

Unlike human isolates, environmental Escherichia coli isolates have not been thoroughly investigated for the diversity and transferability of antibiotic-resistant plasmids. In this study, antibiotic-resistant strains from marine sediment (n = 50) and clams (n = 53) were analyzed (i) for their plasmid content using a PCR-based plasmid replicon typing (PBRT) kit and (ii) for the transferability of plasmid-associated antibiotic resistance (AR) traits by mating experiments. Fifteen of the thirty replicons targeted by the PBRT kit were detected in the isolates; 8/15 were identified in both sediment and clam isolates, although at different frequencies. The most frequent replicons in sediment (74%) and in clam strains (66%) alike, were FIA, FIB, or FII, which are associated with the IncF group, followed by the I1α replicon, which was more frequent in clam (24.5%) than in sediment (10%) strains. More than 50% of the strains contained multiple replicons; although 15 were untypable, S1-PFGE analysis demonstrated that 14/15 carried no plasmids. All cryptic strains were successfully typed and were positive for IncF or IncI replicons. Antibiotic-resistant strains accounted for 63% of all isolates and were significantly (p < 0.05) more frequent in phylogroup A. Most (35%) multidrug-resistant (MDR) strains belonged to phylogroup A, too. Although 25/26 MDR strains were positive for IncF plasmids (the exception being a clam strain), the FII-FIB rep combination was predominant (63%) among the sediment isolates, whereas most clam isolates (40%) carried the FII replicon alone. In mating experiments, selected MDR strains carrying FIB, FII, and I1α replicons, used as the donors, transferred multiple ARs together with the IncF or IncI plasmids at high frequency. Since IncI plasmids are common in E. coli and Salmonella enterica isolates from poultry, our findings suggest an animal origin to the E. coli clam strains carrying IncI plasmids. They also suggest a role for IncI plasmids in the spread of ARs among environmental Enterobacteriaceae and, through the food chain, to human isolates. In conclusion, the PBRT kit proved to be a useful tool to identify plasmids carrying antibiotic-resistant genes and to shed light on the factors underpinning their diffusion.

Regional differences in presence of Shiga toxin-producing Escherichia coli virulence-associated genes in the environment in the North West and East Anglian regions of England

Shiga toxin-producing Escherichia coli is carried in the intestine of ruminant animals, and outbreaks have occurred after contact with ruminant animals or their environment. The presence of STEC virulence genes in the environment was investigated along recreational walking paths in the North West and East Anglia regions of England. In all, 720 boot sock samples from walkers' shoes were collected between April 2013 and July 2014. Multiplex PCR was used to detect E. coli based on the amplification of the uidA gene and investigate STEC-associated virulence genes eaeA, stx1 and stx2. The eaeA virulence gene was detected in 45·5% of the samples, where stx1 and/or stx2 was detected in 12·4% of samples. There was a difference between the two regions sampled, with the North West exhibiting a higher proportion of positive boot socks for stx compared to East Anglia. In univariate analysis, ground conditions, river flow and temperature were associated with positive boot socks. The detection of stx genes in the soil samples suggests that STEC is present in the English countryside and individuals may be at risk for infection after outdoor activities even if there is no direct contact with animals. SIGNIFICANCE AND IMPACT OF THE STUDY: Several outbreaks within the UK have highlighted the danger of contracting Shiga toxin-producing Escherichia coli from contact with areas recently vacated by livestock. This is more likely to occur for STEC infections compared to other zoonotic bacteria given the low infectious dose required. While studies have determined the prevalence of STEC within farms and petting zoos, determining the risk to individuals enjoying recreational outdoor activities that occur near where livestock may be present is less researched. This study describes the prevalence with which stx genes, indicative of STEC bacteria, were found in the environment in the English countryside.

Routine antibiotic therapy in dogs increases the detection of antimicrobial-resistant faecal Escherichia coli

Background

Antimicrobial resistance (AMR) is a critical health problem, with systemic antimicrobial therapy driving development of AMR across the host spectrum.

Objectives

This study compares longitudinal carriage, at multiple timepoints, of AMR faecal Escherichia coli in dogs undergoing routine antimicrobial treatment.

Methods

Faecal samples (n = 457) from dogs (n = 127) were examined pretreatment, immediately after treatment and 1 month and 3 months post-treatment with one of five antimicrobials. Isolates were tested for susceptibility to a range of antimicrobials using disc diffusion for each treatment group at different timepoints; the presence/absence of corresponding resistance genes was investigated using PCR assays. The impact of treatment group/timepoint and other risk factors on the presence of resistance [MDR, fluoroquinolone resistance, third-generation cephalosporin resistance (3GCR) and ESBL and AmpC production] was investigated using multilevel modelling. Samples with at least one AMR E. coli from selective/non-selective agar were classed as positive. Resistance was also assessed at the isolate level, determining the abundance of AMR from non-selective culture.

Results

Treatment with β-lactams or fluoroquinolones was significantly associated with the detection of 3GCR, AmpC-producing, MDR and/or fluoroquinolone-resistant E. coli, but not ESBL-producing E. coli, immediately after treatment. However, 1 month post-treatment, only amoxicillin/clavulanate was significantly associated with the detection of 3GCR; there was no significant difference at 3 months post-treatment for any antimicrobial compared with pretreatment samples.

Conclusions

Our findings demonstrated that β-lactam and fluoroquinolone antibiotic usage is associated with increased detection of important phenotypic and genotypic AMR faecal E. coli following routine therapy in vet-visiting dogs. This has important implications for veterinary and public health in terms of antimicrobial prescribing and biosecurity protocols, and dog waste disposal.

Emergence of carriage of CTX-M-15 in faecal Escherichia coli in horses at an equine hospital in the UK; increasing prevalence over a decade (2008-2017)

Background

This study investigated changes over time in the epidemiology of extended-spectrum β-lactamase (ESBL) producing Escherichia coli within a single equine referral hospital in the UK. Faecal samples were collected from hospitalised horses in 2008 and 2017, processed using selective media and standard susceptibility laboratory methods. A novel real-time PCR with high resolution melt analysis was used to distinguish bla_CTX-M-1 and bla_CTX-M-15 within CTX-M-1 group.

Results

In 2008, 457 faecal samples from 103 horses were collected, with ESBL-producing E. coli identified in 131 samples (28.7, 95% CI 24.6–33.1). In 2017, 314 faecal samples were collected from 74 horses with ESBL-producing E. coli identified in 157 samples (50.0, 95% CI 44.5–55.5). There were 135 and 187 non-duplicate ESBL-producing isolates from 2008 and 2017, respectively. In 2008, 12.6% of isolates belonged to CTX-M-1 group, all carrying bla_CTX-M-1, whilst in 2017, 94.1% of isolates were CTX-M-1 group positive and of these 39.2 and 60.8% of isolates carried bla_CTX-M-1 and bla_CTX-M-15, respectively. In addition, the prevalence of doxycycline, gentamicin and 3rd generation cephalosporin resistance increased significantly from 2008 to 2017 while a decreased prevalence of phenotypic resistance to potentiated sulphonamides was observed.

Conclusions

The real-time PCR proved a reliable and high throughput method to distinguish between bla_CTX-M-1 and bla_CTX-M-15. Furthermore, its use in this study demonstrated the emergence of faecal carriage of CTX-M-15 in hospitalised horses, with an increase in prevalence of ESBL-producing E. coli as well as increased antimicrobial resistance to frequently used antimicrobials.

Diversity, Virulence, and Clinical Significance of Extended-Spectrum β-Lactamase- and pAmpC-Producing Escherichia coli From Companion Animals

Escherichia coli are opportunistic pathogens with the potential to cause a variety of infections in both humans and animals and in many cases have developed antimicrobial resistance. In this study, we characterized extended-spectrum cephalosporin resistant (ESCR) E. coli isolates from diseased companion animals (dogs, cats, and horses) and related the results to clinical findings. ESCR E. coli clinical isolates obtained over a 6-year period were screened for extended-spectrum β-lactamase (ESBL) and/or plasmid mediated AmpC (pAmpC) and virulence markers likely to be associated with extraintestinal pathogenic E. coli (ExPEC). ESBL and/or pAmpC genetic determinants were identified in 79.9% of the ESCR E. coli isolates with bla_CTX-M genes being the most common ESBL genotype of which bla_CTX-M-15, bla_CTX-M-14, and bla_CTX-M-55 were the most prevalent. In addition, bla_{CMY -2} was the most common genotype identified amongst pAmpC producing isolates. Phylogenetic group typing showed that B2 was the most prevalent phylogroup among the ESCR E. coli isolates, followed by the closely related phylogroups D and F which are also associated with extra-intestinal infections. ESCR was also identified in phylogroups commonly regarded as commensals (B1, A, and C). Virulence factor (VF) scores >2 were mostly present amongst isolates in phylogroup B2. Higher virulence scores were found in isolates lacking ESBL/pAmpC resistance genes compared with those carrying both genes (p < 0.05). Five of phylogroup B2 isolates, were typed to the pandemic virulent O25b-ST131 clone and three ST131 isolates carrying bla_CTX-M-15 belonged to the subclade C2/H30Rx whilst one isolate carrying bla_CTX-M-27 typed to the recently described sub-clade C1-M27. MLST typing also identified other sequence types commonly associated with infections in humans (ST410, ST10, and ST648). Most ESCR E. coli isolates obtained in pure growth were cultured from normally sterile body sites (mostly from urinary tract infections, UTIs) whilst only a small proportion were obtained from body sites populated with commensal flora (p < 0.0001). Our study has shown that ExPEC ESBL/pAmpC producing E. coli isolates are common amongst companion animal isolates and are associated with colonization and infection. In addition, their isolation from a normally sterile site is likely to be clinically significant and warrants antimicrobial treatment.

Shiga toxin-producing Escherichia coli in wild ungulates

Shiga toxin-producing Escherichia coli (STEC) are zoonotic pathogens that live in the gastrointestinal tract of wildlife and cattle without causing disease. In humans, their colonization and infection lead to life-threatening disease. We investigated the occurrence of STEC in wild ungulates (wild boar, red deer and roe deer) inhabiting areas differently impacted by anthropogenic activities. STEC were detected in 9% (n = 6) of the samples and were recovered from the three species: 1 of wild boar, 4 of red deer and 1 of roe deer. All the isolates (n = 7) were non-O157 STEC encoding stx1 (n = 2; 29%) and/or stx2 genes (n = 6; 86%). O27:H30 was the most frequent serotype identified, followed by O146:H21 and O146:H28. Two STEC were O-untypable: ONT:H28 and ONT:H52. The phylo-groups identified were B1 (n = 3), E (n = 3) and F (n = 1). All the isolates recovered were susceptible to the different classes of antibiotics tested, although resistance genes were found in two strains. Apart from stx, all STEC encode many virulence factors (VF), particularly adhesins and/or other toxins. A strain with 13 VF collected from roe deer has a high enterohemorrhagic risk due to the presence of intimin, hemolysin and protease effectors genes. Enterohemorrhagic E. coli (EHEC) are implicated in the major cases of human infection and mortality, highlighting the zoonotic potential of wildlife-associated STEC. Wild ungulates are reservoirs of STEC potentially pathogenic to humans. Therefore, following the One Health concept, it is crucial to establish worldwide local monitoring programs that will benefit human, animal and environmental health.

Prevalence of faecal carriage of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in veterinary hospital staff and students

Extended-spectrum β-lactamase (ESBL)-producing bacteria causing clinical infections are often also multidrug-resistant (MDR; resistance to ≥3 antimicrobial drug classes), therefore treatment options may be limited. High carriage rates of these potentially zoonotic bacteria have been found in livestock and companion animals. Therefore, people working in veterinary hospitals may be a high-risk population for carriage. This is the first study to determine the prevalence and longitudinal carriage of antimicrobial-resistant (AMR) and ESBL-producing faecal Escherichia coli in veterinary hospital staff and students. Prevalence of faecal AMR and ESBL-producing E coli was determined in 84 staff members and students in three UK veterinary hospitals. Twenty-seven participants were followed for six weeks to investigate longitudinal carriage. Antimicrobial susceptibility and phenotypic ESBL production were determined and selected isolates were whole genome sequenced. ESBL-producing E coli were isolated from five participants (5.95 per cent; 95 per cent CI 0.89 to 11.0 per cent); two participants carried ESBL-producing E coli resistant to all antimicrobials tested. Carriage of MDR E coli was common (32.1 per cent; 95per cent CI 22.2 to 42.1 per cent) and there was a high prevalence of ciprofloxacin resistance (11.9 per cent; 95 per cent CI 4.98 to 18.8 per cent). ESBL-producing E coli were isolated from seven longitudinal participants (25.9 per cent; 95 per cent CI 9.40 to 42.5 per cent); two participants carried ESBL-producing E coli for the entire study period. Twenty-six participants (96.3 per cent; 95 per cent CI 89.2 to 100) carried ≥1 MDR E coli isolate during the six-week period, with seven participants (25.9 per cent) carrying ≥1 MDR isolate for at least five out of six weeks. The prevalence of faecal ESBL-producing E coli in cross-sectional participants is similar to asymptomatic general populations. However, much higher levels of carriage were observed longitudinally in participants. It is vital that veterinary hospitals implement gold-standard biosecurity to prevent transmission of MDR and ESBL-producing bacteria between patients and staff. Healthcare providers should be made aware that people working in veterinary hospitals are a high-risk population for carriage of MDR and ESBL-producing bacteria, and that this poses a risk to the carrier and for transmission of resistance throughout the wider community.

The Transferable Resistome of Produce

Produce is increasingly recognized as a reservoir of human pathogens and transferable antibiotic resistance genes. This study aimed to explore methods to characterize the transferable resistome of bacteria associated with produce. Mixed salad, arugula, and cilantro purchased from supermarkets in Germany were analyzed by means of cultivation- and DNA-based methods. Before and after a nonselective enrichment step, tetracycline (TET)-resistant Escherichia coli were isolated and plasmids conferring TET resistance were captured by exogenous plasmid isolation. TET-resistant E. coli isolates, transconjugants, and total community DNA (TC-DNA) from the microbial fraction detached from leaves or after enrichment were analyzed for the presence of resistance genes, class 1 integrons, and various plasmids by real-time PCR and PCR-Southern blot hybridization. Real-time PCR primers were developed for IncI and IncF plasmids. TET-resistant E. coli isolated from arugula and cilantro carried IncF, IncI1, IncN, IncHI1, IncU, and IncX1 plasmids. Three isolates from cilantro were positive for IncN plasmids and blaCTX-M-1 From mixed salad and cilantro, IncF, IncI1, and IncP-1β plasmids were captured exogenously. Importantly, whereas direct detection of IncI and IncF plasmids in TC-DNA failed, these plasmids became detectable in DNA extracted from enrichment cultures. This confirms that cultivation-independent DNA-based methods are not always sufficiently sensitive to detect the transferable resistome in the rare microbiome. In summary, this study showed that an impressive diversity of self-transmissible multiple resistance plasmids was detected in bacteria associated with produce that is consumed raw, and exogenous capturing into E. coli suggests that they could transfer to gut bacteria as well.IMPORTANCE Produce is one of the most popular food commodities. Unfortunately, leafy greens can be a reservoir of transferable antibiotic resistance genes. We found that IncF and IncI plasmids were the most prevalent plasmid types in E. coli isolates from produce. This study highlights the importance of the rare microbiome associated with produce as a source of antibiotic resistance genes that might escape cultivation-independent detection, yet may be transferred to human pathogens or commensals.

Are the Hands of Veterinary Staff a Reservoir for Antimicrobial-Resistant Bacteria? A Randomized Study to Evaluate Two Hand Hygiene Rubs in a Veterinary Hospital

Hand hygiene (HH) is the most successful intervention for hospital infection control. HH rubs with residual action are desired. This study aimed to compare the efficacy of alcohol (A-HH) and lactic acid (LA-HH) rubs, with the latter being marketed as having residual activity. We investigated reductions in bacterial colony-forming units (CFUs), prevalence of antimicrobial-resistant (AMR) organisms, and risk factors for increased counts on the hands of veterinary staff. A randomized, crossover study (53 individuals) was performed in a referral veterinary teaching hospital. Hand plates were taken before, immediately after, and 6 hours after HH. A blinded investigator counted CFUs per plate. Methicillin-resistant Staphylococcus aureus/pseudintermedius (MRSA/MRSP), Enterobacteriaceae, and Pseudomonas species (spp.) were characterized. Gender, profession, time point, and HH product were included as variables within multivariable analyses. A significant reduction in bacterial CFU was seen immediately after A-HH rub application (p < 0.001); however, neither product showed any significant residual action. Veterinarians had higher bacterial CFUs than nurses (p = 0.005); contact with patients, rather than the environment, was also associated with higher counts (p < 0.001). MRSA, MRSP, Enterobacteriaceae spp., and Pseudomonas spp. were detected on 7%, 2%, 14%, and 2% of study participant's hands (n = 208 samples), respectively. Frequent HH administration using an A-HH rub was effective at reducing bacterial CFU on hands in vivo in this veterinary hospital setting, but its use needs further encouragement in veterinary staff. The high prevalence of antimicrobial bacteria on hands is of concern; they might act as reservoirs for patients, the environment, and in-contact people.

Fluoroquinolone-resistant and extended-spectrum beta-lactamase producing Escherichia coli isolates from free-living wild animals

During the hunting season 2013-2014, fecal samples collected from hare, roe deer, deer and wild boars were sent to the bacteriology laboratory for the isolation of Escherichia coli and multidrug resistant isolates were characterized phenotypically and genotypically. Out of 106 fecal samples, E. coli was isolated from 101 samples. Although the majority of isolates belonged to phylogenetic groups A and B1, 14 out of 101 isolates were affiliated to group B2. A multidrug resistance phenotype was determined in 7 isolates, all of which had distinguishable genomic macrorestriction profiles. PCR analysis and sequencing revealed a variety of resistance genes, gene cassettes and cassette arrays in these multidrug resistant isolates. Resistance to fluoroquinolones was found in five E. coli isolates (two from a roe deer, one from a deer and two from a wild boar) and multiple mutations in the chromosomal topoisomerase genes were identified. In an E.coli isolate from a hare, the qnrB19 gene was detected. The same isolate carried an aadA23 gene cassette in class 1 integron. In addition, an extended- spectrum beta-lactamase bla_CTX-M-1 gene was detected in an E. coli isolate from a roe deer. The gene was located on a conjugative multi resistance plasmid, which was transferable to a plasmid free E. coli recipient. In conclusion, a number of resistance genes and mobile genetic elements were detected in E. coli isolates from wildlife in Vojvodina, emphasizing the role of environmental pollution in spreading resistant bacteria.

Study of the In Vitro Antagonistic Activity of Various Single-Strain and Multi-Strain Probiotics against Escherichia coli

Escherichia coli is an important commensal of our gut, however, many pathogenic strains exist, causing various severe infections in the gut or beyond. Due to several antibiotic resistance patterns of E. coli, research of alternative treatments or adjuvant therapy is important. One of these is the use of probiotics as antagonistic agents against E. coli. Most published studies investigate only one strain of E. coli and single-strain probiotics. The objectives of this study were to evaluate the antagonistic activity of selected single-strain and multi-strain probiotic supplements against selected clinical E. coli pathotypes using the in vitro agar spot test and the co-culturing method. Molecular methods were used to determine the presence of the genus lactobacilli and bifidobacteria as well as certain selected strains in the probiotic supplements. The agar-spot test showed that the multi-strain probiotics were more effective than the single-strain probiotics. On the other hand, the co-culturing method showed the opposite result, indicating that results are importantly influenced by the chosen method. The most effective single-strain probiotics against E. coli strains were Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus reuteri DSM 17938. The most effective multi-strain probiotics contained lactobacilli, bifidobacteria and enterococci strains, thus proving that most effective probiotics against E. coli strains are the lactic acid bacteria and bifidobacteria. The overall results from both in vitro tests reveal that all selected probiotics exhibited an antagonistic activity against all E. coli strains. From a public health perspective probiotics have thus proved to be successful in inhibiting the growth of E. coli and could therefore be used as adjuvant therapy or alternative therapy in E. coli infections.

Detection and discrimination of five E. coli pathotypes using a combinatory SYBR® Green qPCR screening system

A detection and discrimination system for five Escherichia coli pathotypes, based on a combination of 13 SYBR® Green qPCR, has been developed, i.e., combinatory SYBR® Green qPCR screening system for pathogenic E. coli (CoSYPS Path E. coli). It allows the discrimination on isolates and the screening of potential presence in food of the following pathotypes of E. coli: shigatoxigenic (STEC) (including enterohemorrhagic (EHEC)), enteropathogenic (EPEC), enteroaggregative (EAggEC), enteroaggregative shigatoxigenic (EAggSTEC), and enteroinvasive (EIEC) E. coli. The SYBR® Green qPCR assays target the uidA, ipaH, eae, aggR, aaiC, stx1, and stx2 genes. uidA controls for E. coli presence and all the other genes are specific targets of E. coli pathotypes. For each gene, two primer pairs have been designed to guarantee a sufficient detection even in case of deletion or polymorphisms in the target gene. Moreover, all the qPCR have been designed to be run together in a single analytical PCR plate. This study includes the primer pairs' design, in silico and in situ selectivity, sensitivity, repeatability, and reproducibility evaluation of the 13 SYBR® Green qPCR assays. Each target displayed a selectivity of 100%. The limit of detection of the 13 assays is between 1 and 10 genomic copies. Their repeatability and reproducibility comply with the European requirements. As a preliminary feasibility study on food, the CoSYPS Path E. coli system was subsequently evaluated on four food matrices artificially contaminated with pathogenic E. coli. It allowed the detection of an initial contamination level as low as 2 to 7 cfu of STEC/25 g of food matrix after 24 h of enrichment.

Factors affecting the presence, genetic diversity and antimicrobial sensitivity of Escherichia coli in poultry meat samples collected from Canberra, Australia

To investigate the factors determining the clonal composition of Escherichia coli in poultry meat samples, 306 samples were collected from 16 shops, representing three supermarket chains and an independent butchery located in each of the four town centers of Canberra, Australia, during the summer, autumn and winter. A total of 3415 E. coli isolates were recovered and assigned to a phylogenetic group using the Clermont quadruplex PCR method, fingerprinted using repetitive element palindromic (REP) PCR and screened for their antimicrobial susceptibility profiles. The probability of detecting E. coli and the number of fingerprint types detected per sample, as well as the phylogroup membership of the isolates and their antimicrobial sensitivity profiles varied, with one or more of retailer, store, meat type, season and husbandry. The results of this study demonstrate that poultry meat products are likely to be contaminated with a genetically diverse community of E. coli and suggest that factors relating to the nature of the meat product and distribution chain are determinants of the observed diversity.

Culture-dependent enumeration methods failed to simultaneously detect disinfectant-injured and genetically modified Escherichia coli in drinking water

Underestimation of Escherichia coli in drinking water, an indicator microorganism of sanitary risk, may result in potential risks of waterborne diseases. However, the detection of disinfectant-injured or genetically modified (GM) E. coli has been largely overlooked so far. To evaluate the accuracy of culture-dependent enumeration with regard to disinfectant-injured and GM E. coli, chlorine- or ozone-injured wild-type (WT) and GM E. coli were prepared and characterized. Then, water samples contaminated with these E. coli strains were assayed by four widely used methods, including lactose tryptose broth-based multiple-tube fermentation (MTF), m-endo-based membrane filtration method (MFM), an enzyme substrate test (EST) known as Colilert, and Petrifilm-based testing slip method (TSM). It was found that MTF was the most effective method to detect disinfectant-injured WT E. coli (with 76.9% trials detecting all these bacteria), while this method could not effectively detect GM E. coli (with uninjured bacteria undetectable and a maximal detection rate of 21.5% for the injured). The EST was the only method which enabled considerable enumeration of uninjured GM E. coli, with a detection rate of over 93%. However, the detection rate declined to lower than 45.4% once the GM E. coli was injured by disinfectants. The MFM was invalid for both disinfectant-injured and GM E. coli. This is the first study to report the failure of these commonly used enumeration methods to simultaneously detect disinfectant-injured and GM E. coli. Thus, it highlights the urgent requirement for the development of a more accurate and versatile enumeration method which allows the detection of disinfectant-injured and GM E. coli on the assessment of microbial quality of drinking water.

Antimicrobial-resistant Escherichia coli in hospitalised companion animals and their hospital environment

INTRODUCTION

Antimicrobial resistance is a growing concern with implications for animal health. This study investigated the prevalence of antimicrobial resistance among commensal and environmental Escherichia coli isolated from animals sampled in referral hospitals in the UK.

MATERIALS AND METHODS

Resistant Escherichia coli isolated from animal faeces and practice environments were tested for susceptibility to antimicrobial agents. PCR and sequencing techniques were used to identify extended spectrum beta-lactamase and AmpC-producer genotypes.

RESULTS

In total, 333 faecal and 257 environmental samples were collected. Multi-drug resistant Escherichia coli were found in 13·1% of faecal and 8·9% of environmental samples. Extended spectrum beta-lactamase and AmpC genes were identified 14% and 7·7% of faecal samples and 8·6% and 8·6% of environmental samples, respectively. The most common extended spectrum beta-lactamase gene type detected was blaCTX-M -15 , although blaTEM-158 was detected in faecal and environmental samples from one practice.

CLINICAL SIGNIFICANCE

Escherichia coli resistant to key antimicrobials were isolated from hospitalised animals and the practice environment. We identified the emergence of the inhibitor resistant and extended spectrum beta-lactamase blaTEM-158 in companion animals. Further investigation to determine risk factors for colonisation with antimicrobial-resistant bacteria is needed to provide evidence for antimicrobial stewardship and infection control programmes.

Copper Is a Host Effector Mobilized to Urine during Urinary Tract Infection To Impair Bacterial Colonization

Urinary tract infection (UTI) is a major global infectious disease affecting millions of people annually. Human urinary copper (Cu) content is elevated during UTI caused by uropathogenic Escherichia coli (UPEC). UPEC upregulates the expression of Cu efflux genes during clinical UTI in patients as an adaptive response to host-derived Cu. Whether Cu is mobilized to urine as a host response to UTI and its role in protection against UTI remain unresolved. To address these questions, we tested the hypothesis that Cu is a host effector mobilized to urine during UTI to limit bacterial growth. Our results reveal that Cu is mobilized to urine during UTI caused by the major uropathogens Proteus mirabilis and Klebsiella pneumoniae, in addition to UPEC, in humans. Ceruloplasmin, a Cu-containing ferroxidase, is found at higher levels in UTI urine than in healthy control urine and serves as the molecular source of urinary Cu during UTI. Our results demonstrate that ceruloplasmin decreases the bioavailability of iron in urine by a transferrin-dependent mechanism. Experimental UTI with UPEC in nonhuman primates recapitulates the increased urinary Cu content observed during clinical UTI. Furthermore, Cu-deficient mice are highly colonized by UPEC, indicating that Cu is involved in the limiting of bacterial growth within the urinary tract. Collectively, our results indicate that Cu is a host effector that is involved in protection against pathogen colonization of the urinary tract. Because urinary Cu levels are amenable to modulation, augmentation of the Cu-based host defense against UTI represents a novel approach to limiting bacterial colonization during UTI.

Carriage of antimicrobial resistant Escherichia coli in dogs: Prevalence, associated risk factors and molecular characteristics

Resistance to antimicrobials, in particular that mediated by extended spectrum β-lactamases (ESBL) and AmpC β-lactamases are frequently reported in bacteria causing canine disease as well as in commensal bacteria, which could be a potential health risk for humans they come into contact with. This cross-sectional study aimed to estimate the prevalence and investigate the molecular characteristics of ESBL and plasmid encoded AmpC (pAmpC)-producing E. coli in the mainland UK vet-visiting canine population and, using responses from detailed questionnaires identify factors associated with their carriage. Faecal samples were cultured for antimicrobial resistant (AMR), ESBL and pAmpC-producing E. coli. A subset of ESBL and pAmpC-producing isolates were subjected to multi-locus sequence typing and DNA microarray analyses. Multivariable logistic regression analysis was used to construct models to identify risk factors associated with multidrug resistant (MDR, resistance to three or more antimicrobial classes), fluoroquinolone resistant, ESBL and AmpC-producing E. coli. AMR E.coli were isolated from 44.8% (n=260) of samples, with 1.9% and 7.1% of samples carrying ESBL and pAmpC-producing E. coli, respectively. MDR E. coli were identified in 18.3% of samples. Recent use of antimicrobials and being fed raw poultry were both identified as risk factors in the outcomes investigated. A number of virulence and resistance genes were identified, including genes associated with extra-intestinal and enteropathogenic E. coli genotypes. Considering the close contact that people have with dogs, the high levels of AMR E. coli in canine faeces may be a potential reservoir of AMR bacteria or resistance determinants.

Characterization of virulence factors and phylogenetic group determination of Escherichia coli isolated from diarrheic and non-diarrheic calves from Brazil

This study aimed to detect virulence factors, pathovars, and phylogenetic groups of Escherichia coli strains obtained from feces of calves with and without diarrhea up to 70 days old and to determine the association between occurrence of diarrhea, phylogenetic groups, and pathovars. Phylo-typing analysis of the 336 E. coli strains isolated from calves with Clermont method showed that 21 (6.25 %) belong to phylogroup A, 228 (67.85 %) to phylogroup B1, 2 (0.6 %) to phylogroup B2, 5 (1.49 %) to phylogroup C, 57 (16.96 %) to phylogroup E, and 3 (0.9 %) to phylogroup F. Phylogroup D was not identified and 20 strains (5.95 %) were assigned as "unknown." The distribution of phylogenetic groups among pathovars showed that NTEC belong to phylogroups B1 (17) and C (4); EPEC to phylogroups B1 (6) and E (8); STEC to phylogroups A (5), B1 (56), B2 (2), C (1), and E (15); EHEC to phylogroups B1 (95) and E (5); and ETEC to phylogroups A (3), B1 (7), and E (10). The EAST-1 strains were phylogroups A (13), B1 (47), E (19), and F (3); E. coli strains of "unknown" phylogroups belonged to pathovars EPEC (1), EHEC (2), STEC (7), and EAST-1 strains (6). ETEC was associated with diarrhea (P = 0.002). Our study did not find association between the phylogenetic background and occurrence of diarrhea (P = 0.164) but did find some relationship in phylogenetic group and pathovar. The study showed that EHEC and STEC are classified as phylogroup B1, EAST-1 phylogroup A, ETEC, and EPEC phylogroup E.

Distribution of Escherichia coli in a coastal lagoon (Venice, Italy): Temporal patterns, genetic diversity and the role of tidal forcing

Despite its worldwide importance as fecal indicator in aquatic systems, little is known about the diversity of Escherichia coli in the environment and the factors driving its spatial distribution. The city of Venice (Italy), lying at the forefront of a large European lagoon, is an ideal site to study the mechanisms driving the fate of fecal bacteria, due to the huge fluxes of tourists, the city's unique architecture (causing poor efficiency of sewages treatment), and the long branching network of canals crossing the city. We summarize the results of a multi-year investigation to study the temporal dynamics of E. coli around the city, describe the population structure (by assigning isolates to their phylogenetic group) and the genotypic diversity, and explore the role of environmental factors in determining its variability. E. coli abundance in water was highly variable, ranging from being undetectable up to 10(4) Colony Forming Units (CFU) per 100 ml. Abundance did not display significant relationships with the water physico-chemical variables. The analysis of the population structure showed the presence of all known phylogroups, including extra-intestinal and potentially pathogenic ones. The genotypic diversity was very high, as likely consequence of the heterogeneous input of fecal bacteria from the city, and showed site-specific patterns. Intensive sampling during the tidal fluctuations highlighted the prominent role of tides, rather than environmental variables, as source of spatial variation, with a more evident influence in water than sediments. These results, the first providing information on the genetic properties, spatial heterogeneity and influence of tides on E. coli populations around Venice, have implications to manage the fecal pollution, and the associated waterborne disease risks, in coastal cities lying in front of lagoons and semi-enclosed basins.

Evaluation of an Inexpensive Growth Medium for Direct Detection of Escherichia coli in Temperate and Sub-Tropical Waters

The cost and complexity of traditional methods for the detection of faecal indicator bacteria, including E. coli, hinder widespread monitoring of drinking water quality, especially in low-income countries and outside controlled laboratory settings. In these settings the problem is exacerbated by the lack of inexpensive media for the detection of E. coli in drinking water. We developed a new low-cost growth medium, aquatest (AT), and validated its use for the direct detection of E. coli in temperate and sub-tropical drinking waters using IDEXX Quanti-Tray^®. AT was compared with IDEXX Colilert-18^® and either EC-MUG or MLSB for detecting low levels of E. coli from water samples from temperate (n = 140; Bristol, UK) and subtropical regions (n = 50, Pretoria/Tshwane, South Africa). Confirmatory testing (n = 418 and 588, respectively) and the comparison of quantitative results were used to assess performance. Sensitivity of AT was higher than Colilert-18^® for water samples in the UK [98.0% vs. 86.9%; p<0.0001] and South Africa [99.5% vs. 93.2%; p = 0.0030]. There was no significant difference in specificity, which was high for both media (>95% in both settings). Quantitative results were comparable and within expected limits. AT is reliable and accurate for the detection of E. coli in temperate and subtropical drinking water. The composition of the new medium is reported herein and can be used freely.

Phenotypic and Phylogenetic Identification of Coliform Bacteria Obtained Using 12 Coliform Methods Approved by the U.S. Environmental Protection Agency

The current definition of coliform bacteria is method dependent, and when different culture-based methods are used, discrepancies in results can occur and affect the accuracy of identification of true coliforms. This study used an alternative approach to the identification of true coliforms by combining the phenotypic traits of the coliform isolates and the phylogenetic affiliation of 16S rRNA gene sequences with the use of lacZ and uidA genes. A collection of 1,404 isolates detected by 12 U.S. Environmental Protection Agency-approved coliform-testing methods were characterized based on their phylogenetic affiliations and responses to their original isolation media and lauryl tryptose broth, m-Endo, and MI agar media. Isolates were phylogenetically classified into 32 true-coliform, or targeted Enterobacteriaceae (TE), groups and 14 noncoliform, or nontargeted Enterobacteriaceae (NTE), groups. It was shown statistically that detecting true-positive (TP) events is more challenging than detecting true-negative (TN) events. Furthermore, most false-negative (FN) events were associated with four TE groups (i.e., Serratia group I and the Providencia, Proteus, and Morganella groups) and most false-positive (FP) events with two NTE groups, the Aeromonas and Plesiomonas groups. In Escherichia coli testing, 18 out of 145 E. coli isolates identified by enzymatic methods were validated as FN. The reasons behind the FP and FN reactions could be explained through analysis of the lacZ and uidA genes. Overall, combining the analyses of the 16S rRNA, lacZ, and uidA genes with the growth responses of TE and NTE on culture-based media is an effective way to evaluate the performance of coliform detection methods.

Understanding the association of Escherichia coli with diverse macroalgae in the lagoon of Venice

Recent studies provided evidence that the macroalga Cladopohora in lakes hosts associated Escherichia coli, with consequences on the environmental and human health. We expanded these investigations to other macroalgae (Ulva spp., Sargassum muticum and Undaria pinnatifida) widespread in the lagoon of Venice (Italy). Attached E. coli were abundant, accounting up to 3,250 CFU gram⁻¹ of alga. Macroalgal-associated isolates belonged to all E. coli phylogroups, including pathogenic ones, and to Escherichia cryptic clades. Attached E. coli showed potential to grow even at in situ temperature on macroalgal extracts as only source of carbon and nutrients, and ability to produce biofilm in vitro. The genotypic diversity of the attached isolates was high, with significant differences between algae and the overlying water. Our evidences suggest that attached populations consist of both resident and transient strains, likely resulting from the heterogeneous input of fecal bacteria from the city. We report that cosmopolitan and invasive macroalgae may serve as source of E. coli, including pathogenic genotypes, and that this habitat can potentially support their growth. Considering the global diffusion of the macroalgae here studied, this phenomenon is likely occurring in other coastal cities worldwide and deserves further investigations from either the sanitary and ecological perspectives.

Role of the ehxA gene from Escherichia coli serotype O82 in hemolysis, biofilm formation, and in vivo virulence

Enterohemorrhagic Escherichia coli (EHEC) strains cause serious gastrointestinal disease, which can lead to potentially life-threatening systemic complications such as hemolytic uremic syndrome. Although the ehx gene is established as a major virulence factor of EHEC, the role of this gene in colonization and biofilm formation remains to be elucidated. We constructed recombinant isogenic mutants of the ehxA locus of E. coli HLJ1122 (serotype O82) using the λ Red homologous recombination system. Significantly higher levels of adherence to human epithelial cells (HEp-2) cells were observed for strain HLJ1122 compared with the mutant strain HLJ1122-ΔehxA (P < 0.05). Strain HLJ1122 also exhibited significantly higher levels of biofilm formation than strain HLJ1122-ΔehxA (P < 0.05). Mice infected with strain HLJ1122 showed severe destruction of the intestinal and gastric mucosa; in contrast, mice infected with HLJ1122-ΔehxA showed limited intestinal pathology, displaying minimal inflammatory infiltrates compared with mock-infected mice. These results showed the multifunctional role of Ehx in E. coli virulence.

High Prevalence of Escherichia coli-Producing CTX-M-15 Extended-Spectrum Beta-Lactamases in Poultry and Human Clinical Isolates in Romania

Use of antibiotics in food animals may contribute to development and spread of resistant organisms, particularly so in some countries. The aim of this study was two-fold; first, to establish the prevalence of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in chicken production in a region within Romania. Second, to study the relatedness of ESBL-producing E. coli isolates recovered from broilers, abattoir workers where the chickens were slaughtered and from the human clinical specimens from two regional hospitals. The results indicated a very high (69%) rate of carriage of ESBL and AmpC-producing E. coli in chickens with 36% CTX-M producers. Sequencing showed that chickens in Romania have the highest worldwide prevalence (53%) of blaCTX-M-15 reported in poultry E. coli isolates. The majority (53%) of the extended-spectrum cephalosporin-resistant E. coli carried plasmid-mediated blaampC genes, mostly blaCMY-2 type, one of the highest prevalences reported in Europe. The predominant CTX-M type found in the human clinical E. coli isolates was blaCTX-M-15 and most isolates coharbored blaOXA-1, blaTEM, and aac(6')-ib-cr. The majority (60%) of the human clinical isolates belonged to the pandemic virulent clone B2-ST131. The clonal relationship between broiler and the human CTX-M-producing E. coli isolates was assessed by macrorestriction pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST), which indicated strain diversity with no common STs found between human and poultry isolates. Moreover, IncI1 was the most prevalent replicon found in broiler ESBL-producing E. coli isolates and also in transconjugants, indicating that plasmids and not clonal spread may play a role in the transfer of blaCTX-M genes. This study identifies a high prevalence of ESBL-producing E. coli from broiler chickens in Romania with a high occurrence incidence of blaCTX-M-15, which reflects the main ESBL type found in human E. coli infections in this country.

Antimicrobial resistance risk factors and characterisation of faecal E. coli isolated from healthy Labrador retrievers in the United Kingdom

Antimicrobial resistant bacteria are increasingly detected from canine samples but few studies have examined commensal isolates in healthy community dogs. We aimed to characterise faecal Escherichia coli from 73 healthy non-veterinarian-visiting and non-antimicrobial treated Labrador retrievers, recruited from dog shows in the North West United Kingdom between November 2010 and June 2011. Each enrolled dog provided one faecal sample for our study. E. coli were isolated from 72/73 (99%) faecal samples. Disc diffusion susceptibility tests were determined for a range of antimicrobials, including phenotypic extended-spectrum beta-lactamase (ESBL) and AmpC-production. PCR assay detected phylogenetic groups and resistance genes (blaCTX-M, blaSHV, blaTEM, blaOXA, blaCIT, qnr), and conjugation experiments were performed to investigate potential transfer of mobile genetic elements. Multivariable logistic regression examined potential risk factors from owner-questionnaires for the presence of antimicrobial resistant faecal E. coli. Antimicrobial resistant, multi-drug resistant (≥3 antimicrobial classes; MDR) and AmpC-producing E. coli were detected in 63%, 30% and 16% of samples, respectively. ESBL-producing E. coli was detected from only one sample and conjugation experiments found that blaCTX-M and blaCIT were transferred from commensal E. coli to a recipient strain. Most isolates were phylogenetic groups B1 and A. Group B2 isolates were associated with lower prevalence of resistance to at least one antimicrobial (P<0.001) and MDR (P<0.001). Significant at P<0.003, was the consumption of raw meat for clavulanate-amoxicillin (OR: 9.57; 95% CI: 2.0-45.7) and third generation cephalosporin resistance (3GCR) (OR: 10.9; 95% CI: 2.2-54.0). AMR E. coli were surprisingly prevalent in this group of non-antimicrobial treated and non-veterinarian-visiting dogs and consumption of raw meat was a significant risk factor for antimicrobial resistance. These findings are of concern due to the increasing popularity of raw-meat canine diets, and the potential for opportunistic infection, zoonotic transmission and transmission of antimicrobial resistant determinants from commensal isolates to potential pathogenic bacteria.

Risk factors for faecal colonisation with Escherichia coli producing extended-spectrum and plasmid-mediated AmpC β-lactamases in dogs

The aim of this study was to assess the prevalence and risk factors for faecal carriage of extended-spectrum β-lactamase (ESBL) and plasmidic AmpC β-lactamase (pAmpC) Escherichia coli producers in dogs. A three-month cross-sectional study was conducted and 151 rectal swabs were obtained from healthy dogs. ESBL and pAmpC genes were detected by PCR and were sequenced. Logistic regression models were used to investigate risk factors for the carriage of ESBL and pAmpC-producing E. coli. About 15 per cent of the isolates carried ESBL genes (blaCTX-M-32 n=8, blaCTX-M-15 n=5, blaCTX-M-1 n=3, blaCTX-M-9-like n=4) and 20 per cent carried pAmpC genes (blaCMY-2 n=23, blaCMY-2-like n=2). Thirteen dogs carried an E. coli isolate with both an ESBL and a pAmpC gene. One E. coli isolate harboured the human blaDHA-1 pAmpC gene, which has not been previously reported in companion animals in Europe. Dogs with a history of antimicrobial therapy in the past year had a higher risk of being carriers of ESBL-producing (P=0.003, OR =7.85) and pAmpC-producing (P=0.005, OR=6.28) E. coli. Dogs from shelter/breeders were approximately three times more likely to have an ESBL- or a pAmpC-producing E. coli than dogs from private owners. Males have a reduced risk of carrying a pAmpC-producing E. coli than females (P=0.017, OR =0.28). The knowledge of potential risk factors may help to limit the impact of resistance through implementation of effective control measures and judicious antimicrobial therapy.

The contribution of systemic Escherichia coli infection to the early mortalities of commercial broiler chickens

Avian pathogenic Escherichia coli (APEC) are a substantial burden to the global poultry industry. APEC cause a syndromic poultry infection known as colibacillosis, which has been previously associated with broiler chickens over 2 weeks old. We recently reported that the intestinal tract of 1-day-old broilers harbours a rich reservoir of potentially pathogenic E. coli. Prior infections of the reproductive tract of breeders, egg hygiene and transportation all contribute to early colonization of the neonatal gut. Up to one-half of all flock deaths occur in the first week of production, but few data are available describing the contribution of E. coli. In the present study, all dead birds collected on the first daily welfare walk 48 and 72 h after chick placement underwent post-mortem examination. Diseased tissues were selectively cultured for E. coli and isolates subsequently virulotyped using 10 APEC virulence-associated genes (VAGs): astA, iss, irp2, iucD, papC, tsh, vat, cvi, sitA and ibeA. Approximately 70% of birds displayed signs of colibacillosis. Thirty distinct virulence profiles were identified among 157 E. coli. Isolates carried between zero and seven VAGs; ∼ 30% of E. coli isolates carried five to seven VAGs, with 12.7% sharing the same VAG profile (astA, iss, irp2, iucD, tsh, cvi and sitA). Overall, this study demonstrates the significant contribution of E. coli infections to early broiler mortalities. The identification of a diverse E. coli population is unsurprising based on our previous findings. This work emphasizes the need for an effective vaccination programme and provides preliminary data for vaccine production.

Fast detection and quantification of Escherichia coli using the base principle of the microbial fuel cell

Escherichia coli is an important microbial indicator of fecal contamination, making accurate quantitative detection of E. coli a key to ensuring public health. In this study, a microbial fuel cell (MFC) was used as a detection unit of an E. coli sensor, and specific enzymes expressed in E. coli, such as β-D-galactosidase (GAL) and β-D-glucuronidase (GUS), were exploited as biological detection elements. As substrates, 4-aminophenyl-β-D-galactopyranoside (4-APGal) were used for GAL detection, whereas 8-hydroxyquinoline glucuronide (8-HQG) and 4-nitrophenyl β-D-glucuronide (PNPG) were used for GUS detection. Once these substrates were hydrolyzed by GAL or GUS, they became electrochemically active products, which were, in turn, oxidized on the anode of the MFC reactor. The power output of the MFC reactor increased sharply when E. coli in the reactor reached the critical concentration. Accordingly, the time required to reach the highest voltage output was recorded as a detection time (DT), and a negative linear relationship was established between DT and the logarithm of the initial concentration of E. coli in the samples studied. The DTs of laboratory samples were 140 min and 560 min for initial concentrations of 1.9 × 10(7) CFU/mL and 42 CFU/mL at 44.5 °C. Moreover, the DTs for GUS assays were further shortened by induction with methyl β-D-glucuronide sodium salt (MetGlu). The quantitative relationship between DTs and initial E. coli concentrations established from replicate laboratory sample assays allowed estimation of the E. coli concentration in environmental samples, but with approximately 100 min of lag time. The lag time was also observed with E. coli samples that were prepared by starving cells in a laboratory.