Overlapped sequence types (STs) and serogroups of avian pathogenic (APEC) and human extra-intestinal pathogenic (ExPEC) Escherichia coli isolated in Brazil

Prevalence of specific serogroups, antibiotic resistance and virulence factors of avian pathogenic Escherichia coli (APEC) isolated from clinical cases: A systematic review and meta-analysis

Pathogenic strains of Escherichia coli infecting poultry, commonly called avian pathogenic E. coli (APEC) present significant risks, to the health of both poultry and the general public. This systematic review aimed to examine the prevalence of APEC serotypes, sequence types (ST), phylogenetic groups, virulence factors and antibiotic resistance patterns based on 189 research papers sourced from PubMed, Web of Science, and ProQuest. Then, data were extracted from the selected studies and analyzed to assess the global distribution and characteristics of APEC strains. The metaprop codes in the Meta and Metafor packages of R as implemented in RStudio were then used to conduct meta-analysis. Among APEC strains identified from these different research reports serogroup O78 had the highest overall prevalence (16 %), followed by serogroups O2 (10 %), and O117 (8 %). The most common ST profiles were ST117 (20 %), ST140 (15 %), ST95 (12 %), and ST131 (9 %). ST117 and ST140 are known reservoirs for pathogenic E. coli in humans. Moreover, phylogenetic assessment highlighted the prevalence of phylogroups A, A1, F, D, and B2 among APEC strains indicating diversity in phylogenetic origin within poultry populations. The presence of antimicrobial resistance was notable among APEC strains against antibiotics such as tetracyclines, penicillins, and cephalosporins. This resistance may be linked to use of antimicrobials in poultry production in certain regions presenting challenges for both animal health management and human infection control. Analysis of sequences linked to adherence or virulence indicated that genes encoding adhesins (csg, fimC), iron/metal uptake (sitB, sitC, iroD) and cytotoxicity (estB, hlyF), and serum resistance (traT, iss) were highly prevalent. These factors have been reported to contribute to APEC host colonization and virulence in poultry. In summary, this overview of the characteristics of APEC highlights the pressing importance of monitoring and implementing management approaches to reduce antimicrobial resistance considering that a phylogenetic diversity of E. coli strains causes infections in both poultry and humans and represents a risk to both animal and public health. Further, determining the major conserved aspects and predominant mechanisms of virulence of APEC is critical for improving diagnostics and developing preventative measures to reduce the burden of infection caused by pathogenic E. coli in poultry and lower risks associated with foodborne transmission of E. coli to humans through poultry and poultry products.

The detection of KPC-2, NDM-1, and VIM-2 carbapenemases in international clones isolated from fresh vegetables highlights an emerging food safety issue

Resistance to carbapenems emerged in clinical settings and has rapidly spread to other sectors, such as food and the environment, representing a One Health problem. In this regard, vegetables contaminated by critical priority pathogens have raised global concerns. Here, we have performed a whole-genome sequence-based analysis of extensively drug-resistant Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa strains isolated from cabbage, spinach, and lettuce, respectively. Genomic analysis revealed the emergence of international and high-risk clones belonging to ST340, ST155, and ST233, harboring a broad resistome to clinically important antimicrobials. In this context, K. pneumoniae, E. coli, and P. aeruginosa strains carried blaKPC-2, blaNDM-1, and blaVIM-2, respectively. The blaKPC-2 gene with a non-Tn4401 element (NTEKPC-Ic) was located on an IncX3-IncU plasmid, while the blaVIM-2 gene was associated with a Tn402-like class 1 integron, In559, on the chromosome. Curiously, the blaNDM-1 gene coexisted with the blaPER-2 gene on an IncC plasmid and the regions harboring both genes contained sequences of Tn3-like element ISKox2-like family transposase. Comparative genomic analysis showed interspecies and clonal transmission of carbapenemase-encoding genes at the human-animal-environmental interface. These findings raise a food safety alert about hospital-associated carbapenemase producers, supporting that fresh vegetables can act as a vehicle for the spread of high-risk clones.

Surveillance of Enterobacteriaceae from Diabetic Foot Infections in a Tunisian Hospital: Detection of E. coli-ST131-blaCTX-M-15 and K. pneumoniae-ST1-blaNDM-1 Strains

The study determined the prevalence, antimicrobial resistant (AMR) determinants, and genetic characteristics of Escherichia coli and Klebsiella pneumoniae isolates from patients with diabetic foot infection (DFI) in a Tunisian hospital. A total of 26 Escherichia spp. and Klebsiella spp. isolates were recovered and identified by MALDI-TOF-MS. Antimicrobial susceptibility testing, the detection of AMR determinants and Shiga-like toxin genes, phylogenetic grouping, and molecular typing were performed. Twelve E. coli, 10 K. pneumoniae, 3 K. oxytoca, and 1 E. hermanii were isolated. A multidrug-resistant phenotype was detected in 65.4% of the isolates. About 30.8% of isolates were extended-spectrum β-lactamase (ESBL) producers and mainly carried blaCTX-M-15 and blaCTX-M-14 genes. One blaNDM-1-producing K. pneumoniae-ST1 strain was identified. Class 1 integrons were detected in 11 isolates and 5 gene cassette arrangements were noted: dfrA1+aadA1 (n = 1), dfrA12+aadA2 (n = 3), and dfrA17+aadA5 (n = 1). Other non-β-lactam resistance genes detected were as follows (number of isolates): aac(3')-II (3), aac(6')-Ib-cr(8), qnrB (2), qnrS (4), cmlA (2), floR (4), sul1 (11), sul2 (11), and sul3 (2). The phylogroup B1 was the most frequent (41.7%) among E. coli, and two ESBL-producing isolates corresponded to the ST131-B2 lineage. The ESBL- and carbapenemase-producing Enterobacteriaceae in DFIs are described for the first time in Tunisia.

Characterization of Escherichia coli pathogenicity and drug resistance in yolk peritonitis

Yolk Peritonitis can lead to a rapid decline in egg production, which seriously affects the health of laying hens and the profitability of chicken farms. Escherichia coli (E. coli) is the most common cause of yolk peritonitis in laying hens. In this study, bacterial samples were collected from the ovaries and fallopian tubes of laying hens with suspected yolk peritonitis from a laying farm in Jiangsu Province, and their pathogenicity and drug resistance were investigated. Initially, morphological and biochemical detection methods were employed to isolate and identify the pathogenic bacteria. The results showed that a total of 16 strains of E. coli were isolated from laying hens with yolk peritonitis. Subsequently, the drug resistance and pathogenicity of a randomly selected E. coli strain were analyzed and predicted by genome sequencing technology, and the drug resistance of E. coli was verified by drug sensitivity test and PCR. Finally, the virulence was verified by infection experiment in mice. The study revealed that the egg-yolk peritonitis in laying hens was caused by E. coli infection, and the genome sequencing analysis revealed that the bacteria had multidrug resistance and high virulence. The drug susceptibility testing indicates that E. coli exhibited resistance to aminoglycosides, β-lactam, macrolides, fluoroquinolones, and sulfonamides. In this study, resistance genes including KdpE, aadA5, APH(3 ")-ID, APH(6)-ID, and TEM-1 were identified, and their expression levels varied across different stages of bacterial growth. The results of virulence analysis indicated a mortality rate of 50% in mice infected with E. coli at a concentration of 2.985 × 107 CFU/mL. E. coli infection resulted in damage to various tissues and organs in mice, with the intestinal tissue structure being the most severely affected. This study provides a reference for the study of drug resistance mechanisms in E. coli and provides valuable insights into the selection of drugs for the treatment of vitelline peritonitis.

Whole-Genome Sequence Analysis of Antibiotic Resistance, Virulence, and Plasmid Dynamics in Multidrug-Resistant E. coli Isolates from Imported Shrimp

We analyzed antimicrobial resistance and virulence traits in multidrug-resistant (MDR) E. coli isolates obtained from imported shrimp using whole-genome sequences (WGSs). Antibiotic resistance profiles were determined phenotypically. WGSs identified key characteristics, including their multilocus sequence type (MLST), serotype, virulence factors, antibiotic resistance genes, and mobile elements. Most of the isolates exhibited resistance to gentamicin, streptomycin, ampicillin, chloramphenicol, nalidixic acid, ciprofloxacin, tetracycline, and trimethoprim/sulfamethoxazole. Multilocus sequence type (MLST), serotype, average nucleotide identity (ANI), and pangenome analysis showed high genomic similarity among isolates, except for EC15 and ECV01. The EC119 plasmid contained a variety of efflux pump genes, including those encoding the acid resistance transcriptional activators (gadE, gadW, and gadX), resistance-nodulation-division-type efflux pumps (mdtE and mdtF), and a metabolite, H1 symporter (MHS) family major facilitator superfamily transporter (MNZ41_23075). Virulence genes displayed diversity, particularly EC15, whose plasmids carried genes for adherence (faeA and faeC-I), invasion (ipaH and virB), and capsule (caf1A and caf1M). This comprehensive analysis illuminates antimicrobial resistance, virulence, and plasmid dynamics in E. coli from imported shrimp and has profound implications for public health, emphasizing the need for continued surveillance and research into the evolution of these important bacterial pathogens.

Raw milk cheeses from Beira Baixa, Portugal-A contributive study for the microbiological hygiene and safety assessment

Due to specific bacterial microbiota, raw milk cheeses have appreciated sensory properties. However, they may pose a threat to consumer safety due to potential pathogens presence. This study evaluated the microbiological contamination of 98 raw milk cheeses from Beira Baixa, Portugal. Presence and enumeration of Coagulase Positive Staphylococci (CPS), Listeria monocytogenes, Salmonella spp., pathogenic Escherichia coli, and indicator microorganisms (non-pathogenic E. coli and Listeria spp.) was attained. E. coli antimicrobial resistance (AMR) was also evaluated. PCR and/or Whole genome sequencing (WGS) was used to characterize E. coli, Salmonella spp. and L. monocytogenes isolates. Sixteen cheeses (16.3%) were classified as Satisfactory, 59 (60.2%) as Borderline and 23 (23.5%) as Unsatisfactory/Potential Injurious to Health. L. monocytogenes, CPS > 104 cfu g-1, Extraintestinal pathogenic E. coli (ExPEC) and Salmonella spp. were detected in 4.1%, 6.1%, 3.1% and 1.0% of the samples, respectively. Listeria innocua (4.1%) and E. coli > 104 cfu g-1 (16.3%) were also detected. AMR E. coli was detected in 23/98 (23.5%) of the cheese samples, of which two were multidrug resistant. WGS identified genotypes already associated to human disease and Listeria spp. cluster analysis indicated that cheese contamination might be related with noncompliance with Good Hygiene Practices during cheese production.

The faecal microbiome of the Australian silver gull contains phylogenetically diverse ExPEC, aEPEC and Escherichia coli carrying the transmissible locus of stress tolerance

Wildlife are implicated in the dissemination of antimicrobial resistance, but their roles as hosts for Escherichia coli that pose a threat to human and animal health is limited. Gulls (family Laridae) in particular, are known to carry diverse lineages of multiple-antibiotic resistant E. coli, including extra-intestinal pathogenic E. coli (ExPEC). Whole genome sequencing of 431 E. coli isolates from 69 healthy Australian silver gulls (Chroicocephalus novaehollandiae) sampled during the 2019 breeding season, and without antibiotic selection, was undertaken to assess carriage in an urban wildlife population. Phylogenetic analysis and genotyping resolved 123 sequence types (STs) representing most phylogroups, and identified diverse ExPEC, including an expansive phylogroup B2 cluster comprising 103 isolates (24 %; 31 STs). Analysis of the mobilome identified: i) widespread carriage of the Yersinia High Pathogenicity Island (HPI), a key ExPEC virulence determinant; ii) broad distribution of two novel phage elements, each carrying sitABCD and iii) carriage of the transmissible locus of stress tolerance (tLST), an element linked to sanitation resistance. Of the 169 HPI carrying isolates, 49 (48 %) represented diverse B2 isolates hosting FII-64 ColV-like plasmids that lacked iutABC and sitABC operons typical of ColV plasmids, but carried the serine protease autotransporter gene, sha. Diverse E. coli also carried archetypal ColV plasmids (52 isolates; 12 %). Clusters of closely related E. coli (<50 SNVs) from ST58, ST457 and ST746, sourced from healthy gulls, humans, and companion animals, were frequently identified. In summary, anthropogenically impacted gulls host an expansive E. coli population, including: i) putative ExPEC that carry ColV virulence gene cargo (101 isolates; 23.4 %) and HPI (169 isolates; 39 %); ii) atypical enteropathogenic E. coli (EPEC) (17 isolates; 3.9 %), and iii) E. coli that carry the tLST (20 isolates; 4.6 %). Gulls play an important role in the evolution and transmission of E. coli that impact human health.

Phenotypic and genotypic characterization of colistin-resistant Escherichia Coli with mcr-4, mcr-5, mcr-6, and mcr-9 genes from broiler chicken and farm environment

BACKGROUND

Colistin is an antibiotic used as a last-resort to treat multidrug-resistant Gram-negative bacterial infections. Colistin had been used for a long time in veterinary medicine for disease control and as a growth promoter in food-producing animals. This excessive use of colistin in food animals causes an increase in colistin resistance. This study aimed to determine molecular characteristics of colistin-resistant Escherichia coli in broiler chicken and chicken farm environments.

RESULTS

Four hundred fifty-three cloacal and farm environment samples were collected from six different commercial chicken farms in Kelantan, Malaysia. E. coli was isolated using standard bacteriological methods, and the isolates were tested for antimicrobial susceptibility using disc diffusion and colistin minimum inhibitory concentration (MIC) by broth microdilution. Multiplex PCR was used to detect mcr genes, and DNA sequencing was used to confirm the resistance genes. Virulence gene detection, phylogroup, and multilocus sequence typing (MLST) were done to further characterize the E. coli isolates. Out of the 425 (94%; 425/453) E. coli isolated from the chicken and farm environment samples, 10.8% (48/425) isolates were carrying one or more colistin-resistance encoding genes. Of the 48 colistin-resistant isolates, 54.2% (26/48) of the mcr positive isolates were genotypically and phenotypically resistant to colistin with MIC of colistin ≥ 4 μg/ml. The most prominent mcr gene detected was mcr-1 (47.9%; 23/48), followed by mcr-8 (18.8%; 9/48), mcr-7 (14.5%; 7/48), mcr-6 (12.5%; 6/48), mcr-4 (2.1%; 1/48), mcr-5 (2.1%; 1/48), and mcr-9 (2.1%; 1/48) genes. One E. coli isolate originating from the fecal sample was found to harbor both mcr-4 and mcr-6 genes and another isolate from the drinking water sample was carrying mcr-1 and mcr-8 genes. The majority of the mcr positive isolates were categorized under phylogroup A followed by phylogroup B1. The most prevalent sequence typing (ST) was ST1771 (n = 4) followed by ST206 (n = 3). 100% of the mcr positive E. coli isolates were multidrug resistant. The most frequently detected virulence genes among mcr positive E. coli isolates were ast (38%; 18/48) followed by iss (23%; 11/48). This is the first research to report the prevalence of mcr-4, mcr-5, mcr-6, mcr-7, and mcr-8 genes in E. coli from broiler chickens and farm environments in Malaysia.

CONCLUSION

Our findings suggest that broiler chickens and broiler farm environments could be reservoirs of colistin-resistant E. coli, posing a risk to public health and food safety.

A Review of Resistance to Polymyxins and Evolving Mobile Colistin Resistance Gene (mcr) among Pathogens of Clinical Significance

The global rise in antibiotic resistance in bacteria poses a major challenge in treating infectious diseases. Polymyxins (e.g., polymyxin B and colistin) are last-resort antibiotics against resistant Gram-negative bacteria, but the effectiveness of polymyxins is decreasing due to widespread resistance among clinical isolates. The aim of this literature review was to decipher the evolving mechanisms of resistance to polymyxins among pathogens of clinical significance. We deciphered the molecular determinants of polymyxin resistance, including distinct intrinsic molecular pathways of resistance as well as evolutionary characteristics of mobile colistin resistance. Among clinical isolates, Acinetobacter stains represent a diversified evolution of resistance, with distinct molecular mechanisms of intrinsic resistance including naxD, lpxACD, and stkR gene deletion. On the other hand, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa are usually resistant via the PhoP-PhoQ and PmrA-PmrB pathways. Molecular evolutionary analysis of mcr genes was undertaken to show relative relatedness across the ten main lineages. Understanding the molecular determinants of resistance to polymyxins may help develop suitable and effective methods for detecting polymyxin resistance determinants and the development of novel antimicrobial molecules.

Plasmid-mediated colistin resistance from fresh meat and slaughtered animals in the Czech Republic: nation-wide surveillance 2020-2021

The aim of this study was to determine the occurrence of plasmid-mediated colistin resistance in domestic and imported meat and slaughter animals in the Czech Republic during 2020-2021 by using selective cultivation and direct PCR testing. A total of 111 colistin-resistant Escherichia coli isolates with mcr-1 gene were obtained from 65 (9.9%, n = 659) samples and subjected to whole-genome sequencing. Isolates with mcr were frequently found in fresh meat from domestic production (14.2%) as well as from import (28.8%). The mcr-1-positive E. coli isolates predominantly originated from meat samples (16.6%), mainly poultry (27.1%), and only minor part of the isolates came from the cecum (1.7%). In contrast to selective cultivation, 205 (31.1%) samples of whole-community DNA were positive for at least one mcr variant, and other genes besides mcr-1 were detected. Analysis of whole-genome data of sequenced E. coli isolates revealed diverse sequence types (STs) including pathogenic lineages and dominance of ST1011 (15.6%) and ST162 (12.8%). Most isolates showed multidrug-resistant profile, and 9% of isolates produced clinically important beta-lactamases. The mcr-1 gene was predominantly located on one of three conjugative plasmids of IncX4 (83.5%), IncI2 (7.3%), and IncHI2 (7.3%) groups. Seventy-two percent isolates of several STs carried ColV plasmids. The study revealed high prevalence of mcr genes in fresh meat of slaughter animals. Our results confirmed previous assumptions that the livestock, especially poultry production, is an important source of colistin-resistant E. coli with the potential of transfer to humans via the food chain. IMPORTANCE We present the first data on nation-wide surveillance of plasmid-mediated colistin resistance in the Czech Republic. High occurrence of plasmid-mediated colistin resistance was found in meat samples, especially in poultry from both domestic production and import, while the presence of mcr genes was lower in the gut of slaughter animals. In contrast to culture-based approach, testing of whole-community DNA showed higher prevalence of mcr and presence of various mcr variants. Our results support the importance of combining cultivation methods with direct culture-independent techniques and highlight the need for harmonized surveillance of plasmid-mediated colistin resistance. Our study confirmed the importance of livestock as a major reservoir of plasmid-mediated colistin resistance and pointed out the risks of poultry meat for the transmission of mcr genes toward humans. We identified several mcr-associated prevalent STs, especially ST1011, which should be monitored further as they represent zoonotic bacteria circulating between different environments.

Distribution of virulence-associated genes, antibiotic resistance and phylogenetic groups in Escherichia coli isolated from domestic and racing pigeons

Despite a lot of information about virulence and resistance of Escherichia coli (E. coli) in poultry, very limited data are currently available on its occurrence in pigeon isolates, although this poses a threat to human and animal health. Therefore, this study was conducted to explore the phylogenetic classification, antibiotic sensitivity, and virulence factors in E. coli isolated from cloacal swabs of domestic pigeons bred for meat (n = 47) and racing pigeons (n = 44). The most frequent phylogroup in racing pigeons was E (36, 82.00%), unlike domestic pigeons (B2- 19, 40.00%). The most abundant iron uptake system in both groups of bird was feoB (racing = 40, 90.90%; domestic = 44, 93.61%). The presence of ibeA (52, 57.10%) and kpsMTII (46, 50.50%) genes was detected in more than half of all strains belonging exclusively to phylogroups B2, D, E, F, clade I. Antibiotic resistance was higher in racing pigeons. All racing pigeon isolates were resistant to tetracycline and trimethoprim + sulphonamide. Resistance to ciprofloxacin was determined in three isolates (6.38%) of domestic and 33 isolates (75%) of racing pigeons. Aminoglycosides and β-lactamases resistance were also recorded. One of the important detected phenotypic mechanisms of resistance occurring in isolates from racing pigeons was AGL AAC(6´)I. Our study confirms that healthy pigeons are a reservoir of antibiotic-resistant E. coli containing an arsenal of virulence factors, thus capable of potentially causing infection. Pigeons with the option to fly to multiple places can transfer virulent and resistant bacteria. Direct contact with pigeons and their faeces and the contamination of water and food pose a threat of infection to humans and other animal species.

Clinically relevant antibiotic resistance in Escherichia coli from black kites in southwestern Siberia: a genetic and phenotypic investigation

Wild birds including raptors can act as vectors of clinically relevant bacteria with antibiotic resistance. The aim of this study was to investigate the occurrence of antibiotic-resistant Escherichia coli in black kites (Milvus migrans) inhabiting localities in proximity to human-influenced environments in southwestern Siberia and investigate their virulence and plasmid contents. A total of 51 E. coli isolates mostly with multidrug resistance (MDR) profiles were obtained from cloacal swabs of 35 (64%, n = 55) kites. Genomic analyses of 36 whole genome sequenced E. coli isolates showed: (i) high prevalence and diversity of their antibiotic resistance genes (ARGs) and common association with ESBL/AmpC production (27/36, 75%), (ii) carriage of mcr-1 for colistin resistance on IncI2 plasmids in kites residing in proximity of two large cities, (iii) frequent association with class one integrase (IntI1, 22/36, 61%), and (iv) presence of sequence types (STs) linked to avian-pathogenic (APEC) and extra-intestinal pathogenic E. coli (ExPEC). Notably, numerous isolates had significant virulence content. One E. coli with APEC-associated ST354 carried qnrE1 encoding fluoroquinolone resistance on IncHI2-ST3 plasmid, the first detection of such a gene in E. coli from wildlife. Our results implicate black kites in southwestern Siberia as reservoirs for antibiotic-resistant E. coli. It also highlights the existing link between proximity of wildlife to human activities and their carriage of MDR bacteria including pathogenic STs with significant and clinically relevant antibiotic resistance determinants. IMPORTANCE Migratory birds have the potential to acquire and disperse clinically relevant antibiotic-resistant bacteria (ARB) and their associated antibiotic resistance genes (ARGs) through vast geographical regions. The opportunistic feeding behavior associated with some raptors including black kites and the growing anthropogenic influence on their natural habitats increase the transmission risk of multidrug resistance (MDR) and pathogenic bacteria from human and agricultural sources into the environment and wildlife. Thus, monitoring studies investigating antibiotic resistance in raptors may provide essential data that facilitate understanding the fate and evolution of ARB and ARGs in the environment and possible health risks for humans and animals associated with the acquisition of these resistance determinants by wildlife.

Whole Genome Sequencing of Avian Pathogenic Escherichia coli Causing Bacterial Chondronecrosis and Osteomyelitis in Australian Poultry

Bacterial chondronecrosis with osteomyelitis (BCO) impacts animal welfare and productivity in the poultry industry worldwide, yet it has an understudied pathogenesis. While Avian Pathogenic Escherichia coli (APEC) are known to be one of the main causes, there is a lack of whole genome sequence data, with only a few BCO-associated APEC (APEC_BCO) genomes available in public databases. In this study, we conducted an analysis of 205 APEC_BCO genome sequences to generate new baseline phylogenomic knowledge regarding the diversity of E. coli sequence types and the presence of virulence associated genes (VAGs). Our findings revealed the following: (i) APEC_BCO are phylogenetically and genotypically similar to APEC that cause colibacillosis (APEC_colibac), with globally disseminated APEC sequence types ST117, ST57, ST69, and ST95 being predominate; (ii) APEC_BCO are frequent carriers of ColV-like plasmids that carry a similar set of VAGs as those found in APEC_colibac. Additionally, we performed genomic comparisons, including a genome-wide association study, with a complementary collection of geotemporally-matched genomes of APEC from multiple cases of colibacillosis (APEC_colibac). Our genome-wide association study found no evidence of novel virulence loci unique to APEC_BCO. Overall, our data indicate that APEC_BCO and APEC_colibac are not distinct subpopulations of APEC. Our publication of these genomes substantially increases the available collection of APEC_BCO genomes and provides insights for the management and treatment strategies of lameness in poultry.

Polymyxin B inhibits pro-inflammatory effects of E. coli outer membrane vesicles whilst increasing immune cell uptake and clearance

Polymyxin B (PMB) is a peptide based antibiotic that binds the lipid A moiety of lipopolysaccharide (LPS) with a resultant bactericidal effect. The interaction of PMB with LPS presented on outer membrane vesicles (OMVs) is not fully known, however, a sacrificial role of OMVs in protecting bacterial cells by sequestering PMB has been described. Here we assess the ability of PMB to neutralize the immune-stimulatory properties of OMVs whilst modulating the uptake of OMVs in human immune cells. We show for the first time that PMB increases immune cell uptake of Escherichia coli derived OMVs whilst inhibiting TNF and IL-1β production. Therefore, we present a potential new role for PMB in the neutralization of OMVs via LPS masking and increased immune cell uptake.

Antimicrobial resistance pattern of avian pathogenic Escherichia coli with detection of extended-spectrum β-lactamase-producing isolates in broilers in east Algeria

Background and Aim: Avian pathogenic Escherichia coli (APEC) is the causative agent of colibacillosis, one of the most prevalent bacterial diseases responsible for significant economic losses in the poultry industry worldwide. This study aimed to assess the antimicrobial resistance (AMR) patterns of APEC isolates recovered from poultry in east Algeria and estimate the prevalence of extended-spectrum β-lactamase (ESBL)-producing isolates. Materials and Methods: In the slaughterhouse of Batna City (Algeria), livers indicating colibacillosis were sampled from 204 suspected carcasses with growth retardation and generalized congestion. Escherichia coli isolation and identification were performed on MacConkey agar using conventional methods and the API 20E system. Antimicrobial resistance susceptibility was tested by the disk diffusion method according to the Clinical Laboratory Standards Institute Guidelines. Extended-spectrum β-lactamase detection was carried out using the double-disk confirmation test. Results: One hundred sixty E. coli isolates were recovered (one isolate per sample). Avian pathogenic Escherichia coli isolates showed high levels of resistance to ampicillin and tetracycline (100%), nalidixic acid (95%), ofloxacin (93.75%), doxycycline (91.87), ciprofloxacin (87.50%), trimethoprim/sulfamethoxazole (62.50%), gentamycin (32.50%), chloramphenicol (27.50%), amoxicillin/clavulanic acid (16.25%), colistin (14.37%), and nitrofurantoin (10.62%). All strains were multidrug-resistant to at least three antibiotics, and more than half (52.52%) of the isolates were resistant to at least seven antibiotics. All isolates were susceptible to ceftriaxone, ceftazidime, and aztreonam. Two E. coli isolates were ESBL producers (1.25%). Conclusion: Avian pathogenic Escherichia coli resistance to most antimicrobial agents used in poultry may lead to antimicrobial therapy failure. Keywords: antimicrobial resistance, avian pathogenic Escherichia coli, broilers, colibacillosis, Eastern Algeria, extended-spectrum β-lactamase.

One health clones of multidrug-resistant Escherichia coli carried by synanthropic animals in Brazil

WHO priority pathogens have disseminated beyond hospital settings and are now being detected in urban and wild animals worldwide. In this regard, synanthropic animals such as urban pigeons (Columba livia) and rodents (Rattus rattus, Rattus norvegicus and Mus musculus) are of interest to public health due to their role as reservoirs of pathogens that can cause severe diseases. These animals usually live in highly contaminated environments and have frequent interactions with humans, domestic animals, and food chain, becoming sentinels of anthropogenic activities. In this study, we report genomic data of Escherichia coli strains selected for ceftriaxone and ciprofloxacin resistance, isolated from pigeons and black rats. Genomic analysis revealed the occurrence of international clones belonging to ST10, ST155, ST224 and ST457, carrying a broad resistome to beta-lactams, aminoglycosides, trimethoprim/sulfamethoxazole, fluoroquinolones, tetracyclines and/or phenicols. SNP-based phylogenomic investigation confirmed clonal relatedness with high-risk lineages circulating at the human-animal-environmental interface globally. Our results confirm the dissemination of WHO priority CTX-M-positive E. coli in urban rodents and pigeons in Brazil, highlighting potential of these animals as infection sources and hotspot for dissemination of clinically relevant pathogens and their resistance genes, which is a critical issue within a One Health perspective.

Comparison of Fitness Cost, Stability, and Conjugation Frequencies of tet(X4)-Positive Plasmids in Chicken and Pig Escherichia coli

The large-scale epidemic of the tet(X4) gene in the livestock and poultry industry is threatening public health; however, there is still a lack of comparative studies on tet(X4)-bearing plasmids in chicken and pig Escherichia coli. To evaluate the prevalence trend of tet(X4)-bearing plasmids and the factors influencing their persistence in the livestock and poultry industry, we examined the fitness cost, stability under tetracyclines pressure, and conjugation frequencies at various temperatures of six tet(X4)-bearing plasmids in four representative pig E. coli isolates and chicken E. coli isolates. Compared with pig E. coli, the plasmid in chicken E. coli showed lower fitness cost, and stronger ability to promote bacterial biofilm formation and motility. Meanwhile, the presence of tetracycline may favor the stability of tet(X4)-bearing plasmids, which was more common in chicken E. coli. Furthermore, the optimal temperature for IncX1 tet(X4)-bearing plasmid conjugation was 42 °C, and its conjugation frequency in chicken E. coli was higher than that in pig E. coli, whereas the optimal temperature for IncFII tet(X4)-bearing plasmid conjugation was 37 °C and it performed better in pig E. coli, suggesting the predominant plasmid types circulating in chicken E. coli and pig E. coli may be distinct. Collectively, although tet(X4) currently appears to be more prevalent in pig E. coli, this is probably independent of the fitness cost caused by tet(X4)-plasmids. To curb the future spread of the tet(X4) gene, reduced tetracyclines usage and tailored interventions should be applied in different breeding industries.

Complete genomic analysis of ST117 lineage extraintestinal pathogenic Escherichia coli (ExPEC) to reveal multiple genetic determinants to drive its global transmission: ST117 E. coli as an emerging multidrug-resistant foodborne ExPEC with zoonotic potential

Avian pathogenic Escherichia coli (APEC) is recognized as a primary source of foodborne extraintestinal pathogenic E. coli (ExPEC), which poses a significant risk of extraintestinal infections in humans. The potential of human infection with ST117 lineage APEC/ExPEC from poultry is particularly concerning. However, relatively few whole-genome studies have focused on ST117 as an emerging ExPEC lineage. In this study, the complete genomes of 11 avian ST117 isolates and the draft genomes of 20 ST117 isolates in China were sequenced to reveal the genomic islands and large plasmid composition of ST117 APEC. With reference to the extensive E. coli genomes available in public databases, large-scale comprehensive genomic analysis of the ST117 lineage APEC/ExPEC was performed to reveal the features of the ST117 pan-genome and population. The high variability of the accessory genome emphasized the diversity and dynamic traits of the ST117 pan-genome. ST117 isolates recovered from different hosts and geographic sources were randomly located on a phylogeny tree, suggesting that ST117 E. coli lacked host specificity. A time-scaled phylogeny tree showed that ST117 was a recent E. coli lineage with a relatively short evolutionary period. Further characterization of a wide diversity of ExPEC-related virulence genes, pathogenicity islands (PAIs), and resistance genes of the ST117 pan-genome provided insights into the virulence and resistance of ST117 APEC/ExPEC. The results suggested zoonotic potential of ST117 APEC/ExPEC between birds and humans. Moreover, genomic analysis showed that a pool of diverse plasmids drove the virulence and multidrug resistance of ST117 APEC/ExPEC. Several types of large plasmids were scattered across the ST117 isolates, but there was no strong plasmid-clade adaptation. Combined with the pan-genome analysis, a double polymerase chain reaction (PCR) method was designed for rapid and cost-effective detection of ST117 isolates from various avian and human APEC/ExPEC isolates. Overall, this study addressed a gap in current knowledge about the ST117 APEC/ExPEC genome, with significant implications to understand the success and spread of ST117 APEC/ExPEC.

Hcp2a of APEC affects mRNA splicing and protein quality control in DF-1 cells

Background

Bacteria deliver effector proteins into the host cell via a secretory system that can directly act on the target to cause disease. As an important pipeline structural protein of the type VI secretion system (T6SS) complex, Hcp acts together with other virulence factors in the target cell. There is growing evidence that T6SS plays a key role in the pathogenic mechanism of APEC. However, the regulatory function played by the effector protein Hcp during its interaction with host cells is not clear. Here, tandem mass tag (TMT) analysis was used to quantify the proteins affected by increased expression of Hcp2a in DF-1 cells.

Results

The host response was significantly different between the overexpression and null groups at the protein level. A total of 195 differentially expressed proteins (DEPs) were detected in the overexpression group (upregulated, n = 144, downregulated, n = 51). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to predict the biological functions and pathways of differentially expressed proteins. The results showed that these DEPs were mainly enriched in RNA degradation, spliceosome, and mRNA surveillance pathways.

Conclusions

This study suggests that Hcp2a, the effector protein of APEC, plays an important role in regulating mRNA splicing and protein quality control in DF-1 cells. These findings provide useful clues to elucidate the pathogenic mechanism of effector protein Hcp2a on host target cells.

Phylotypic Profiling, Distribution of Pathogenicity Island Markers, and Antimicrobial Susceptibility of Escherichia coli Isolated from Retail Chicken Meat and Humans

Escherichia coli (E.coli) found in retail chicken meat could be causing a wide range of infections in humans and constitute a potential risk. This study aimed to evaluate 60 E. coli isolates from retail chicken meat (n = 34) and human urinary tract infections (UTIs, n = 26) for phylogenetic diversity, presence of pathogenicity island (PAI) markers, antimicrobial susceptibility phenotypes, and antimicrobial resistance genes, and to evaluate their biofilm formation capacity. In that context, confirmed E.coli isolates were subjected to phylogrouping analysis using triplex PCR, antimicrobial susceptibility testing using the Kirby–Bauer disc diffusion method; PAI distribution was investigated by using two multiplex PCRs. Most of the chicken isolates (22/34, 64.7%) were identified as commensal E. coli (A and B1), while 12 isolates (35.3%) were classified as pathogenic virulent E. coli (B2 and D). Similarly, the commensal group dominated in human isolates. Overall, 23 PAIs were detected in the chicken isolates; among them, 39.1% (9/23) were assigned to group B1, 34.8% (8/23) to group A, 4.34% (1/23) to group B2, and 21.7% (5/23) to group D. However, 25 PAIs were identified from the human isolates. PAI IV536 was the most prevalent (55.9%, 69.2%) PAI detected in both sources. In total, 37 (61.7%) isolates of the chicken and human isolates were biofilm producers. Noticeably, 100% of E. coli isolates were resistant to penicillin and rifamycin. Markedly, all E. coli isolates displayed multiple antibiotic resistance (MAR) phenotypes, and the multiple antibiotic resistance index (MARI) among E. coli isolates ranged between 0.5 and 1. Several antibiotic resistance genes (ARGs) were identified by a PCR assay; the sul2 gene was the most prevalent (38/60, 63.3%) from both sources. Interestingly, a significant positive association (r = 0.31) between biofilm production and resistance to quinolones by the qnr gene was found by the correlation analysis. These findings were suggestive of the transmission of PAI markers and antibiotic resistance genes from poultry to humans or humans to humans through the food chain. To avoid the spread of virulent and multidrug-resistant E. coli, intensive surveillance of retail chicken meat markets is required.

A comparative genomics approach for identifying genetic factors in Escherichia coli isolates associated with bovine diseases

AIMS

Escherichia coli are ubiquitously present bacterial pathogens that cause septicaemia, diarrhoea and other clinical illness in farm animals. Many pathogen factors can be associated with disease conditions. Currently, studies inferring E. coli genetic factors associated with infection in bovines are limited. Hence, the present study envisaged to determine the pathogen genetic factors associated with bovine disease conditions.

METHOD AND RESULTS

The comparative genomic analysis involved genome sequence data of 135 diseased and 145 healthy bovine origin E. coli strains. Phylogroups A and C, as well as pathotypes ExPEC and EPEC, were found to have a strong connection with bovine disease strains. STEC strains, including EHEC, seem to play a less important role in bovine disease. Sequence types (STs) predominant among strains from diarrhoeal origin were ST 301 (CC 165) and ST 342. Correlation of core genome phylogeny with accessory gene based clustering, phylogroups and pathotypes indicated lineage specific virulence factors mostly associated with disease conditions.

CONCLUSIONS

Comparative genomic analysis was applied to infer genetic factors significant in bovine disease origin E. coli strains. Isolates from bovine disease origin were enriched for the phylogroups A and C, and for the pathotypes ExPEC and EPEC. However, there was minimal evidence of STEC involvement. The study also indicated predominant genetic lineages and virulence genes (pap, sfa and afa) associated with disease origin strains. SIGNIFICANCE AND IMPACT OF STUDY;: The study revealed significant pathotypes, phylgroups, serotypes and sequence types associated with bovine disease conditions. These identified genetic factors can be applied for disease diagnosis, implementing vaccine and therapeutic measures. In addition, E. coli isolates from the bovine species revealed a complex pattern of disease epidemiology.

World Health Organization critical priority Escherichia coli clone ST648 in magnificent frigatebird (Fregata magnificens) of an uninhabited insular environment

Antimicrobial resistance is an ancient natural phenomenon increasingly pressured by anthropogenic activities. Escherichia coli has been used as markers of environmental contamination and human-related activity. Seabirds may be bioindicators of clinically relevant bacterial pathogens and their antimicrobial resistance genes, including extended-spectrum-beta-lactamase (ESBL) and/or plasmid-encoded AmpC (pAmpC), in anthropized and remote areas. We evaluated cloacal swabs of 20 wild magnificent frigatebirds (Fregata magnificens) of the Alcatrazes Archipelago, the biggest breeding colony of magnificent frigatebirds in the southern Atlantic and a natural protected area with no history of human occupation, located in the anthropized southeastern Brazilian coast. We characterized a highly virulent multidrug-resistant ST648 (O153:H9) pandemic clone, harboring blaCTX–M–2, blaCMY–2, qnrB, tetB, sul1, sul2, aadA1, aac(3)-VIa and mdfA, and virulence genes characteristic of avian pathogenic (APEC) (hlyF, iroN, iss, iutA, and ompT) and other extraintestinal E. coli (ExPEC) (chuA, kpsMII, and papC). To our knowledge, this is the first report of ST648 E. coli co-producing ESBL and pAmpC in wild birds inhabiting insular environments. We suggest this potentially zoonotic and pathogenic lineage was likely acquired through indirect anthropogenic contamination of the marine environment, ingestion of contaminated seafood, or by intra and/or interspecific contact. Our findings reinforce the role of wild birds as anthropization sentinels in insular environments and the importance of wildlife surveillance studies on pathogens of critical priority classified by the World Health Organization.

A Siderophore-Encoding Plasmid Encodes High-Level Virulence in Escherichia coli

A plasmid that harbored the virulence factors highly like those of the virulence plasmid commonly found in clinical hypervirulent Klebsiella pneumoniae strains was detected in a foodborne Escherichia coli strain EC1108 and designated p1108-IncFIB. This virulent-like plasmid was found to be common in E. coli from various sources. To understand the contribution of this plasmid to the virulence of E. coli, plasmid p1108-IncFIB in strain EC1108 was first cured to generate strain EC1108-PC. The virulence plasmid p15WZ-82_Vir in Klebsiella pneumoniae strain 15WZ-82 was then transmitted to EC1108-PC to produce the transconjugant, EC1108-PC-TC to assess the contribution of this virulence plasmid to the virulence level of E. coli. During the process of conjugation, p15WZ-82_Vir was found to be evolved into p15WZ-82_int, which underwent homologous recombination with a plasmid encoding a carbapenemase gene, bla_NDM-1, p1108-NDM, in EC1108-PC. Comparison between the level of virulence in the EC1108, EC1108-PC-TC, and EC1108-PC through serum and macrophage resistance assay, as well as animal experiments, confirmed that plasmid p1108-IncFIB encoded a high level of virulence in E. coli, yet the fusion plasmid derived from p15WZ-82_Vir did not encode virulence but instead imposed a high fitness cost in the E. coli strain EC1108-PC-TC. These findings indicate that E. coli strains carrying the virulence plasmid p1108-IncFIB in multidrug-resistant (MDR) strains may also impose serious public health threats like that of hypervirulent Klebsiella pneumoniae strains harboring the p15WZ-82_Vir plasmid.

IMPORTANCE Acquisition of pLVPK-like virulence plasmid by Klebsiella pneumoniae converts it to hypervirulent K. pneumoniae (HvKP), which has become one of the most important clinical bacterial pathogens. The potential of transmission of this virulence plasmid and its contribution to the virulence of other Enterobacteriaceae, such as E. coli, are not clear yet. In this study, we showed that pLVPK-like virulence plasmid exhibited fitness costs and did not contribute to the virulence in E. coli. However, we identified a novel virulence plasmid, p1108-IncFIB, that encodes similar siderophore genes as those of pLVPK from a foodborne E. coli strain and showed that p1108-IncFIB encoded a high level of virulence in E. coli. BLAST of E. coli genomes from GenBank showed that these siderophore genes were widespread in clinical E. coli strains. Further studies are warranted to understand the impact of this plasmid in the control of clinical infections caused by E. coli.

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.

A rich mosaic of resistance in extended-spectrum β-lactamase-producing Escherichia coli isolated from red foxes (Vulpes vulpes) in Poland as a potential effect of increasing synanthropization

In our research, we analyzed the resistance of cephalosporin-resistant E. coli strains to antimicrobial agents. The strains were collected during five years from wild animal species commonly inhabiting Poland. We have identified the type of β-lactamases produced and the multidrug-resistance profile. Most strains (73.8%) had genes encoding ESBL enzymes, mainly CTX-M-1 and TEM. Almost all AmpC-β-lactamase-producing isolates had the bla_CMY-2 gene. Almost 70% of the strains tested showed a multi-drug resistance profile. The dominant phenotype was resistance to tetracycline (69.05%), and/or sulfamethoxazole (57.1%). We also found high resistance to quinolones: ciprofloxacin 35.7% and nalidixic acid 52.4%. The phenotypic resistance of the strains was in most cases confirmed by the presence of corresponding genes. Among strains, 26.2% were carriers of plasmid-mediated quinolone resistance genes (PMQR). MLST analysis revealed a large clonal variation of the strains, which was reflected in 28 different sequence types. More than half of the strains (54.7%) were classified into the following sequence complexes: 10, 23, 69, 101, 155, 156, 168, 354, 398, 446, and 648. Only one strain in the studied group was assigned to the ExPEC pathotype and represented sequence type 117. The results of our research have confirmed that isolates obtained from wild animals possess many resistance determinants and sequence types, which are also found in food-producing animals and humans. This reflects the doctrine of "One health", which clearly indicates that human health is inextricably linked with animal health as well as degree of environmental contamination. We conclude that the resistance and virulence profiles of strains isolated from wildlife animals may be a resultant of various sources encountered by animals, creating a rich and varied mosaic of genes, which is very often unpredictable and not reflected in the correlation between the sequence type and the gene profile of resistance or virulence observed in epidemic clones.

Virulome and genome analyses identify associations between antimicrobial resistance genes and virulence factors in highly drug-resistant Escherichia coli isolated from veal calves

Food animals are known reservoirs of multidrug-resistant (MDR) Escherichia coli, but information regarding the factors influencing colonization by these organisms is lacking. Here we report the genomic analysis of 66 MDR E. coli isolates from non-redundant veal calf fecal samples. Genes conferring resistance to aminoglycosides, β-lactams, sulfonamides, and tetracyclines were the most frequent antimicrobial resistance genes (ARGs) detected and included those that confer resistance to clinically significant antibiotics (bla_CMY-2, bla_CTX-M, mph(A), erm(B), aac(6’)Ib-cr, and qnrS1). Co-occurrence analyses indicated that multiple ARGs significantly co-occurred with each other, and with metal and biocide resistance genes (MRGs and BRGs). Genomic analysis also indicated that the MDR E. coli isolated from veal calves were highly diverse. The most frequently detected genotype was phylogroup A-ST Cplx 10. A high percentage of isolates (50%) were identified as sequence types that are the causative agents of extra-intestinal infections (ExPECs), such as ST69, ST410, ST117, ST88, ST617, ST648, ST10, ST58, and ST167, and an appreciable number of these isolates encoded virulence factors involved in the colonization and infection of the human urinary tract. There was a significant difference in the presence of multiple accessory virulence factors (VFs) between MDR and susceptible strains. VFs associated with enterohemorrhagic infections, such as stx, tir, and eae, were more likely to be harbored by antimicrobial-susceptible strains, while factors associated with extraintestinal infections such as the sit system, aerobactin, and pap fimbriae genes were more likely to be encoded in resistant strains. A comparative analysis of SNPs between strains indicated that several closely related strains were recovered from animals on different farms indicating the potential for resistant strains to circulate among farms. These results indicate that veal calves are a reservoir for a diverse group of MDR E. coli that harbor various resistance genes and virulence factors associated with human infections. Evidence of co-occurrence of ARGs with MRGs, BRGs, and iron-scavenging genes (sit and aerobactin) may lead to management strategies for reducing colonization of resistant bacteria in the calf gut.

Whole-genome sequencing and gene sharing network analysis powered by machine learning identifies antibiotic resistance sharing between animals, humans and environment in livestock farming

Anthropogenic environments such as those created by intensive farming of livestock, have been proposed to provide ideal selection pressure for the emergence of antimicrobial-resistant Escherichia coli bacteria and antimicrobial resistance genes (ARGs) and spread to humans. Here, we performed a longitudinal study in a large-scale commercial poultry farm in China, collecting E. coli isolates from both farm and slaughterhouse; targeting animals, carcasses, workers and their households and environment. By using whole-genome phylogenetic analysis and network analysis based on single nucleotide polymorphisms (SNPs), we found highly interrelated non-pathogenic and pathogenic E. coli strains with phylogenetic intermixing, and a high prevalence of shared multidrug resistance profiles amongst livestock, human and environment. Through an original data processing pipeline which combines omics, machine learning, gene sharing network and mobile genetic elements analysis, we investigated the resistance to 26 different antimicrobials and identified 361 genes associated to antimicrobial resistance (AMR) phenotypes; 58 of these were known AMR-associated genes and 35 were associated to multidrug resistance. We uncovered an extensive network of genes, correlated to AMR phenotypes, shared among livestock, humans, farm and slaughterhouse environments. We also found several human, livestock and environmental isolates sharing closely related mobile genetic elements carrying ARGs across host species and environments. In a scenario where no consensus exists on how antibiotic use in the livestock may affect antibiotic resistance in the human population, our findings provide novel insights into the broader epidemiology of antimicrobial resistance in livestock farming. Moreover, our original data analysis method has the potential to uncover AMR transmission pathways when applied to the study of other pathogens active in other anthropogenic environments characterised by complex interconnections between host species.

Livestock have been suggested as an important source of antimicrobial-resistant (AMR) Escherichia coli, capable of infecting humans and carrying resistance to drugs used in human medicine. China has a large intensive livestock farming industry, poultry being the second most important source of meat in the country, and is the largest user of antibiotics for food production in the world. Here we studied antimicrobial resistance gene overlap between E. coli isolates collected from humans, livestock and their shared environments in a large-scale Chinese poultry farm and associated slaughterhouse. By using a computational approach that integrates machine learning, whole-genome sequencing, gene sharing network and mobile genetic elements analysis we characterized the E. coli community structure, antimicrobial resistance phenotypes and the genetic relatedness of non-pathogenic and pathogenic E. coli strains. We uncovered the network of genes, associated with AMR, shared across host species (animals and workers) and environments (farm and slaughterhouse). Our approach opens up new avenues for the development of a fast, affordable and effective computational solutions that provide novel insights into the broader epidemiology of antimicrobial resistance in livestock farming.

Characterization and antimicrobial susceptibility of biofilm-producing Avian Pathogenic Escherichia coli from broiler chickens and their environment in India

Avian pathogenic Escherichia coli (APEC) is responsible for colibacillosis in poultry. APEC remains a constant problem for the poultry industry, despite the use of antimicrobials and disinfectants in farms. The endemicity of APEC in poultry farms is associated with its biofilm-forming ability, which is further aggravated by various virulence factors and resistance to multiple drugs that help bacteria to thrive under different environmental conditions. To characterize APEC from affected broiler chickens and their environments, samples (n=114) from dead birds (heart, liver, lungs, and cloacal swab) and surrounding environments such as feeder, drinker, litter, PVC pipe, water tank wall, feed, and water were collected. The collected samples were subjected to microbial isolation using MacConkey Lactose agar (MLA) and Eosin Methylene Blue agar (EMB), which led to the isolation of 62 E. coli isolates. This was confirmed by uspA gene amplification and Vitek 2 Compact. These isolates were characterized using a set of five virulence genes (hlyF, ompT, iroN, iss, iutA), which yielded 47 (75.80%) isolates as APEC and the remaining as non-APEC. Furthermore, all the 62 isolates were subjected to microtiter plate assay for biofilm detection and the result showed that 36 (58.06%) isolates were able to form moderate to strong biofilms in Trypticase soy broth (TSB) at 72h of incubation. Of the 36 biofilm-producing isolates, 30 were APEC. Biofilm-related genes (crl, csgA, fimH, luxS, and papC) were also detected with higher prevalence among APEC isolates. Antimicrobial susceptibility test using Vitek 2 Compact revealed 43 (91.48%) of 47 APEC isolates as multiple drug resistant (MDR) and 8 (17.02%) as ESBL positive. This study reveals that APEC with biofilm formation ability is present in poultry farms. Further studies are needed to understand the role of biofilms in the pathogenesis and antimicrobial resistance of APEC.

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli survey in wild seabirds at a pristine atoll in the southern Atlantic Ocean, Brazil: First report of the O25b-ST131 clone harboring blaCTX-M-8

Antimicrobial resistance is among the most serious public health threats of the 21st century, with great impact in terms of One Health. Among antimicrobial resistant bacteria (ARB), extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) represent major challenges to human healthcare. Wild birds have been commonly used as environmental bioindicators of ESBL-EC. Remote locations represent a unique opportunity to evaluate the occurrence, dissemination and epidemiology of ARB in the environment. Herein we surveyed ESBL-EC in 204 cloacal swabs from six nonsynanthropic seabird species at the pristine Rocas Atoll, Brazil. We identified ESBL-EC isolates in 2.4% (5/204) of the tested seabirds, all in magnificent frigatebirds (Fregata magnificens). We isolated strains of O25b-ST131-fimH22 harboring gene bla_CTX-M-8 (3 clones), ST117 harboring gene bla_SHV-12, and a novel ST11350 (clonal complex 349) harboring genes bla_CTX-M-55 and fosA3. All the isolates presented Extraintestinal pathogenic E. coli (ExPEC) virulence profiles. We suggest that magnificent frigatebirds may act as "flying bridges", transporting ESBL-EC and ARGs from an anthropogenically-impacted archipelago geographically close to our pristine and remote study site. The characteristics of our isolates suggest zoonotic potential and, despite the apparent good health of all the evaluated birds, may represent a hypothetical potential threat to the avian population using the atoll. To our knowledge, this is the first description of: (1) the pandemic and public health relevant ST131-O25b harboring bla_CTX-M-8 worldwide; (2) ST131-fimH22 in wild birds; and (3); fosA3 in wildlife. Our findings expand the current epidemiological knowledge regarding host and geographical distribution of ESBL-EC and ARGs in wild birds, and emphasize the disseminating characteristics and adaptability of ST131 and ST117 strains within the human-animal-interface. Herein we discuss the involvement of nonsynanthropic wild birds in the epidemiology of antimicrobial resistance and their potential as sentinels of ESBL E. coli in insular environments.

Virulence Genotype and Phenotype of Multiple Antimicrobial-Resistant Escherichia coli Isolates from Broilers Assessed from a "One-Health" Perspective

ABSTRACT

Extraintestinal pathogenic Escherichia coli (ExPEC) include several serotypes that have been associated with colibacillosis in poultry and with urinary tract infections (UTIs) and newborn meningitis in humans. In this study, 57 antimicrobial-resistant E. coli from apparently healthy broiler chickens were characterized for their health and safety risks. These isolates belonged to 12 serotypes, and isolates of the same serotype were clonal based on single nucleotide variant analysis. Most of the isolates harbored plasmids; IncC and IncFIA were frequently detected. The majority of the resistant isolates harbored plasmid-mediated resistance genes, including aph(3″)-Ib, aph(6)-Id, blaCMY-2, floR, sul1, sul2, tet(A), and tet(B), in agreement with their resistant phenotypes. The class 1 integron was detected in all E. coli serotypes except O124:H25 and O7:H6. Of the 57 broiler E. coli isolates, 27 were avian pathogenic, among which 18 were also uropathogenic E. coli and the remainder were other ExPEC. The two isolates of serotype O161:H4 (ST117) were genetically related to the control avian pathogenic strains and a clinical isolate associated with UTIs. A strain of serotype O159:H45 (ST101) also was closely related to a UTI isolate. The detected virulence factors included adhesins, invasins, siderophores, type III secretion systems, and toxins in combination with other virulence determinants. A broiler isolate of serotype O7:H18 (ST38) carried the ibeA gene encoding a protein involved in invasion of brain endothelium on a 102-kbp genetic island. This isolate moderately adhered and invaded Caco-2 cells and induced mortality (42.5%) in a day-old-chick infection model. The results of this study suggest that multiple antimicrobial-resistant E. coli isolates recovered from apparent healthy broilers can be pathogenic and act as reservoirs for antimicrobial resistance genes, highlighting the necessity of their assessment in a "One-Heath" context.

HIGHLIGHTS

Presence of the Extended-Spectrum-β-Lactamase and Plasmid-Mediated AmpC-Encoding Genes in Escherichia coli from Companion Animals-A Study from a University-Based Veterinary Hospital in Taipei, Taiwan

Extended-spectrum-β-lactamase (ESBL) and AmpC β-lactamase are two enzymes commonly found in Enterobacteriaceae that confer resistance to major antibiotics, such as third-generation cephalosporins that are widely prescribed for both human and animals. We screened for Escherichia coli producing ESBL and plasmid-mediated AmpC β-lactamase (pAmpC) from dogs and cats brought to National Taiwan University Veterinary Hospital, Taipei, Taiwan from 29 June 2020, to 31 December 2020. The genotypes and phylogenetic relatedness of these E. coli were also analyzed. Fifty samples of E. coli obtained from 249 bacterial isolates were included in this study. Among them, eight isolates had ESBL, seven had pAmpC, and one had both. Thirty-two percent (16/50) of E. coli isolates were resistant to third-generation cephalosporins. The detected ESBL genes included the bla_CTX-M-1 and bla_CTX-M-9 groups, and the bla_CMY-2 group was the only gene type found in pAmpC. ESBL-producing E. coli belonged to the pathogenic phylogroup B2, and the sequence types (STs) were ST131 and ST1193. Three isolates were determined to be ST131-O25b, a highly virulent epidemic clone. The pAmpC-producing E. coli were distributed in multiple phylogroups, primarily the commensal phylogroup B1. The STs of the pAmpC-producing E. coli included ST155, ST315, ST617, ST457, ST767, ST372, and ST93; all of these have been reported in humans and animals. Imipenem was active against all the ESBL/pAmpC-producing E. coli; however, since in humans it is a last-resort antimicrobial, its use in companion animals should be restricted.

Molecular Epidemiology of Multidrug-Resistant Uropathogenic Escherichia coli O25b Strains Associated with Complicated Urinary Tract Infection in Children

Background: Uropathogenic Escherichia coli (UPEC) has increased the incidence of urinary tract infection (UTI). It is the cause of more than 80% of community-acquired cystitis cases and more than 70% of uncomplicated acute pyelonephritis cases. Aim: The present study describes the molecular epidemiology of UPEC O25b clinical strains based on their resistance profiles, virulence genes, and genetic diversity. Methods: Resistance profiles were identified using the Kirby–Bauer method, including the phenotypic production of extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs). The UPEC serogroups, phylogenetic groups, virulence genes, and integrons were determined via multiplex PCR. Genetic diversity was established using pulsed-field gel electrophoresis (PFGE), and sequence type (ST) was determined via multilocus sequence typing (MLST). Results: UPEC strains (n = 126) from hospitalized children with complicated UTIs (cUTIs) were identified as O25b, of which 41.27% were multidrug resistant (MDR) and 15.87% were extensively drug resistant (XDR). The O25b strains harbored the fimH (95.23%), csgA (91.26%), papGII (80.95%), chuA (95.23%), iutD (88.09%), satA (84.92%), and intl1 (47.61%) genes. Moreover, 64.28% were producers of ESBLs and had high genetic diversity. ST131 (63.63%) was associated primarily with phylogenetic group B2, and ST69 (100%) was associated primarily with phylogenetic group D. Conclusion: UPEC O25b/ST131 harbors a wide genetic diversity of virulence and resistance genes, which contribute to cUTIs in pediatrics.

Antimicrobial Susceptibility and Detection of Virulence-Associated Genes in Escherichia coli Strains Isolated from Commercial Broilers

The aim of this study was to investigate the presence of iron-uptake and virulence genes, antibiotic resistance profiles, and phylogenetic relatedness in 115 Escherichia coli (E. coli) strains isolated from broilers in Slovakia and to determine their potential threat to human health. The most frequent phylogroups were B1 (37%) and A (21%), and 33.9% strains were included in pathogenic groups. The commonly observed iron-uptake genes were feoB (94%), sitA (83%), and iutA (58%). Protectins (iss, kpsMTII) were identified in 30% of samples. Four percent of B2-associated broilers carried the papC (P fimbria) gene connected with upper urinary tract infection. The dominant resistance was to tetracycline (49%), ampicillin (66%), ampicillin + sulbactam (27%), ciprofloxacin (61%), and trimethoprim + sulfonamide (34%); moreover, sporadically occurring resistance to cephalosporins, aminoglycosides, fluoroquinolones, and polypeptide colistin was observed. Genotypic analysis of resistance revealed the presence of bla_CTX-M-1 and bla_CTX-M-2 in two isolates from broilers. Commercial broilers can be reservoirs of virulent and resistant genes as well as E. coli causing (extra-)intestinal infections, which can be a potential threat to humans via direct contact and food.

Occurrence of genes associated with virulence in Escherichia coli isolates from chicken carcasses at different stages of processing at a slaughterhouse

Escherichia coli is a bacterium frequently found in chicken carcasses, causing carcass condemnation with losses to the industry and when present in food, it carries a risk to public health as there is evidence that some strains pathogenic to birds (APEC - Avian Pathogenic E. coli) have zoonotic potential. Carcass contamination can occur at the slaughterhouse, but the influence of the different stages of processing in the selection of potential extraintestinal pathogenic E. coli strains is unknown. This study aimed to analyze the influence of the processing steps in the slaughterhouse on the detection of E. coli isolates carrying APEC predictor's virulence-associated genes (VAGs), and to relate their presence with post-mortem condemnation. A sample consisted of four pooled carcasses collected at seven different stages of slaughter (before scalding, after scalding, after plucking, before evisceration/after shower wash, after evisceration, after pre-coolers, and after packing) from 15 batches of broilers. The total samples obtained was 105 pools with four carcasses each, totaling 420 carcasses analyzed. Enterobacteriaceae were counted from each pool and E. coli were subsequently selected, which were submitted to pentaplex PCR to identify the five VAG APEC predictor's: iroN, ompT, hlyF, iss, and iutA. The Enterobacteriaceae count demonstrated a reduction of 4.25 log CFU per gram of carcass from the first to the last stage analyzed, with scalding and pre-cooling by immersion being the procedures that contributed most to this reduction. The presence of VAGs and potential APEC (presence of two or more of these gene predictors) was observed at all points evaluated in the slaughterhouse, which suggested that bacteria carrying these genes could reach the consumer.

Co-relationship between Escherichia coli in broiler cellulitis and liver lesions

Pathogenic strains of Escherichia coli may invade the subcutaneous tissue of poultry and cause cellulitis, whilst the pathogen may also cause lesions in internal organs such as the liver. Current paper co-relates Escherichia coli and virulence genes characteristic of Avian Pathogenic Escherichia coli (APEC) in broilers´ cellulitis and liver lesions. One hundred carcasses were retrieved from the production chain in an avian abattoir in the state of Bahia, Brazil, between August 2013 and January 2014, due to detection of cellulitis lesions. Cellulitis and liver samples were retrieved aseptically to quantify E. coli by Petrifilm™ count fast method (3M Company) (AOAC 998.8). Virulent genes iss and iutA were removed from E. coli isolates by Polymerase Chain Reaction (PCR). Escherichia coli was isolated from 82.0% of broilers removed from the production chain and the bacterium was concomitantly detected in cellulitis and liver lesions in 40.0% of broilers. E. coli counts ranged between 1.00 and 4.73 log CFU/g in liver lesions and between 2.00 and 9.00 log UFC/g in cellulitis lesions. Virulent genes iutA and iss were detected in 97.56% and 89.02% of E. coli isolates, respectively. Genotype analysis demonstrated the concomitant amplification of genes iutA and iss in 60.0% (n=40) of samples of cellulitis and liver lesions in which the simultaneous isolation of E. coli occurred. There was a positive and significant co-relationship (r=0.22; p<0.05) between the variables occurrence of E. coli isolated from liver samples and the occurrence of E. coli isolated from cellulitis lesions. There were also positive and significant co-relationships between populations of E. coli from liver isolates and cellulitis lesions (r=0.46; p<0.05) when E. coli isolated in the liver and in cellulitis lesions was detected. Since results showed a relationship between E. coli in cellulitis and liver lesions and possible systemic infection, the occurrence of cellulitis lesions as a criterion for total discarding of carcass may be suggested.

The Avian Pathogenic Escherichia coli (APEC) pathotype is comprised of multiple distinct, independent genotypes

Avian Pathogenic E. coli (APEC) is the causative agent of avian colibacillosis, resulting in economic losses to the poultry industry through morbidity, mortality and carcass condemnation, and impacts the welfare of poultry. Colibacillosis remains a complex disease to manage, hampered by diagnostic and classification strategies for E. coli that are inadequate for defining APEC. However, increased accessibility of whole genome sequencing (WGS) technology has enabled phylogenetic approaches to be applied to the classification of E. coli and genomic characterization of the most common APEC serotypes associated with colibacillosis O1, O2 and O78. These approaches have demonstrated that the O78 serotype is representative of two distinct APEC lineages, ST-23 in phylogroup C and ST-117 in phylogroup G. The O1 and O2 serotypes belong to a third lineage comprised of three sub-populations in phylogroup B2; ST-95, ST-140 and ST-428/ST-429. The frequency with which these genotypes are associated with colibacillosis implicates them as the predominant APEC populations and distinct from those causing incidental or opportunistic infections. The fact that these are disparate clusters from multiple phylogroups suggests that these lineages may have become adapted to the poultry niche independently. WGS studies have highlighted the limitations of traditional APEC classification and can now provide a path towards a robust and more meaningful definition of the APEC pathotype. Future studies should focus on characterizing individual APEC populations in detail and using this information to develop improved diagnostics and interventions.

Dynamics of extended-spectrum cephalosporin-resistant Escherichia coli in pig farms: A longitudinal study

OBJECTIVES

Point prevalence estimates of extended-spectrum cephalosporin-resistant Escherichia coli (ESC-R-Ec) are important surveillance measures but may not uncover the ESC-R-Ec dynamics within pig farms. A longitudinal study was therefore performed by sampling individual pigs, pig farmers and the environment.

METHODS

On average, 30 (range 10-46) piglets of 31 Swiss farms were sampled during the suckling, weaning and fattening stages (n= 2437 samples). In addition, stool from pig farmers and environmental samples were obtained and metadata collected by questionnaires. ESC-R-Ec was identified by routine culture, and clonal relationships and resistance genes were derived from whole genome sequencing data.

RESULTS

Working on pig farms was not associated with an increased prevalence of ESC-R-Ec in humans. ESC-R-Ec prevalence significantly decreased from 6.2% to 3.9% and 1.8% for the suckling, weaned and fattening pigs, respectively (P < 0.001). Within the 57 ESC-R-positive suckling piglets, persisting carriage was detected in 25 animals at two consecutive time points and one animal at three consecutive time points. Clonal spread (n=7 farms, 22.6%) and horizontal gene transfer (n=1 farm, 3%) within pigs but not between humans and animals was detected. Liquid manure (n=10 samples, 16.7%) was identified as the major environmental reservoir of ESC-R-Ec in the pig farm environment.

CONCLUSIONS

Pig farming practices like all-in-all-out systems, but not antimicrobial usage, were associated with reduced risk of ESC-R-Ec at the farm level. As carriage duration is normally short within the individual pigs, the risk of recolonisation and clonal spread of ESC-R-Ec might be reduced by applying appropriate decontamination strategies.

Waterborne Urinary Tract Infections: Have We Overlooked an Important Source of Exposure?

The presence of intestinal pathogenic Escherichia coli in drinking water is well recognized as a risk for diarrhea. The role of drinking water in extraintestinal infections caused by E. coli-such as urinary tract infections (UTIs)-remains poorly understood. Urinary tract infections are a leading cause of outpatient infections globally, with a lifetime incidence of 50-60% in adult women. We reviewed the scientific literature on the occurrence of uropathogenic E. coli (UPEC) in water supplies to determine whether the waterborne route may be an important, overlooked, source of UPEC. A limited number of studies have assessed whether UPEC isolates are present in drinking water supplies, but no studies have measured whether their presence in water may increase UPEC colonization or the risk of UTIs in humans. Given the prevalence of drinking water supplies contaminated with E. coli across the globe, efforts should be made to characterize UTI-related risks associated with drinking water, as well as other pathways of exposure.

Characterization of beta-lactam-resistant Escherichia coli from Australian fruit bats indicates anthropogenic origins

Antimicrobial-resistant Escherichia coli, particularly those resistant to critically important antimicrobials, are increasingly reported in wildlife. The dissemination of antimicrobial-resistant bacteria to wildlife indicates the far-reaching impact of selective pressures imposed by humans on bacteria through misuse of antimicrobials. The grey-headed flying fox (GHFF; Pteropus poliocephalus), a fruit bat endemic to eastern Australia, commonly inhabits urban environments and encounters human microbial pollution. To determine if GHFF have acquired human-associated bacteria, faecal samples from wild GHFF (n=287) and captive GHFF undergoing rehabilitation following illness or injury (n=31) were cultured to detect beta-lactam-resistant E. coli. Antimicrobial susceptibility testing, PCR and whole genome sequencing were used to determine phenotypic and genotypic antimicrobial resistance profiles, strain type and virulence factor profiles. Overall, 3.8 % of GHFF carried amoxicillin-resistant E. coli (wild 3.5 % and captive 6.5 %), with 38.5 % of the 13 GHFF E. coli isolates exhibiting multidrug resistance. Carbapenem (blaNDM-5) and fluoroquinolone resistance were detected in one E. coli isolate, and two isolates were resistant to third-generation cephalosporins (blaCTX-M-27 and ampC). Resistance to tetracycline and trimethoprim plus sulfamethoxazole were detected in 69.2% and 30.8 % of isolates respectively. Class 1 integrons, a genetic determinant of resistance, were detected in 38.5 % of isolates. Nine of the GHFF isolates (69.2 %) harboured extraintestinal virulence factors. Phylogenetic analysis placed the 13 GHFF isolates in lineages associated with humans and/or domestic animals. Three isolates were human-associated extraintestinal pathogenic E. coli (ST10 O89:H9, ST73 and ST394) and seven isolates belonged to lineages associated with extraintestinal disease in both humans and domestic animals (ST88, ST117, ST131, ST155 complex, ST398 and ST1850). This study provides evidence of anthropogenic multidrug-resistant and pathogenic E. coli transmission to wildlife, further demonstrating the necessity for incorporating wildlife surveillance within the One Health approach to managing antimicrobial resistance.

Comparative Characteristics and Zoonotic Potential of Avian Pathogenic Escherichia coli (APEC) Isolates from Chicken and Duck in South Korea

Avian pathogenic Escherichia coli (APEC) causes colibacillosis, which is an economically important disease in the poultry industry worldwide. The present study investigated O-serogroups, phylogenetic groups, antimicrobial resistance, and the existence of virulence-associated genes (VAGs) and antimicrobial resistance genes in 125 APEC isolates between 2018 and 2019 in Korea. The phylogenetic group B2 isolates were confirmed for human-related sequence types (STs) through multi-locus sequence typing (MLST). O-serogroups O2 (12.5%) and O78 (10.3%) and phylogenetic group B1 (36.5%) and A (34.5%) were predominant in chicken and duck isolates, respectively. Out of 14 VAGs, iucD, iroN, hlyF, and iss were found significantly more in chicken isolates than duck isolates (p < 0.05). The resistance to ampicillin, ceftiofur, ceftriaxone, and gentamicin was higher in chicken isolates than duck isolates (p < 0.05). The multidrug resistance (MDR) rates of chicken and duck isolates were 77.1% and 65.5%, respectively. One isolate resistant to colistin (MIC 16 μg/mL) carried mcr-1. The B2-ST95 APEC isolates possessed more than 9 VAGs, and most of them were MDR (82.4%). This report is the first to compare the characteristics of APEC isolates from chickens and ducks in Korea and to demonstrate that B2-ST95 isolates circulating in Korea have zoonotic potential and pose a public health risk.

Multi-Drug Resistant Plasmids with ESBL/AmpC and mcr-5.1 in Paraguayan Poultry Farms: The Linkage of Antibiotic Resistance and Hatcheries

Poultry represents a common source of bacteria with resistance to antibiotics including the critically important ones. Selective cultivation using colistin, cefotaxime and meropenem was performed for 66 chicken samples coming from 12 farms in Paraguay while two breeding companies supplied the farms. A total of 62 Escherichia coli and 22 Klebsiella pneumoniae isolates were obtained and representative isolates were subjected to whole-genome sequencing. Relatively high prevalence of phylogenetic group D and F was observed in E. coli isolates and several zoonotic sequence types (STs) including ST457 (14 isolates), ST38 (5), ST10 (2), ST117 (2) or ST93 (4) were detected. Isolates from three farms, which purchased chicken from a Paraguayan hatchery showed higher prevalence of mcr-5.1 and bla_CTX-M-8 compared to the other nine farms, which purchased chickens from a Brazilian hatchery. Moreover, none of the K. pneumoniae isolates were linked to the Paraguayan hatchery. ESBL/AmpC and mcr-5-carrying multi-drug resistant (MDR) plasmids were characterized, and complete sequences were obtained for eight plasmids. The study shed light on Paraguayan poultry farms as a reservoir of antibiotic resistance commonly conferred via MDR plasmids and showed linkage between resistance and origin of the chickens at the hatcheries level.

Prevalence and Antibiotic Resistance Characteristics of Extraintestinal Pathogenic Escherichia coli among Healthy Chickens from Farms and Live Poultry Markets in China

Simple Summary

Chicken meat has been proved to be a suspected source of extraintestinal pathogenic Escherichia coli (ExPEC), causing several diseases in humans, and bacteria in healthy chickens can contaminate chicken carcasses at the slaughter; however, reports about the prevalence and molecular characteristics of ExPEC in healthy chickens are still rare. In this study, among 926 E. coli isolates from healthy chickens in China, 22 (2.4%) were qualified as ExPEC and these ExPEC isolates were clonally unrelated. A total of six serogroups were identified in this study, with O78 being the most predominant type, and all the six serogroups had been frequently reported in human ExPEC isolates in many countries. All the 22 ExPEC isolates were multidrug-resistant and most isolates carried both bla_CTX-M and fosA3 resistance genes. Notably, plasmid-borne colistin resistance gene mcr-1 was identified in six ExPEC isolates, among which two carried additional carbapenemase gene bla_NDM, compromising both the efficacies of the two critically important drugs for humans, carbapenems and colistin. These results highlight that healthy chickens can serve as a potential reservoir for multidrug resistant ExPEC isolates, including mcr-1-containing ExPEC.

Abstract

Chicken products and chickens with colibacillosis are often reported to be a suspected source of extraintestinal pathogenic Escherichia coli (ExPEC) causing several diseases in humans. Such pathogens in healthy chickens can also contaminate chicken carcasses at the slaughter and then are transmitted to humans via food supply; however, reports about the ExPEC in healthy chickens are still rare. In this study, we determined the prevalence and characteristics of ExPEC isolates in healthy chickens in China. A total of 926 E. coli isolates from seven layer farms (371 isolates), one white-feather broiler farm (78 isolates) and 17 live poultry markets (477 isolates from yellow-feather broilers) in 10 cities in China, were isolated and analyzed for antibiotic resistance phenotypes and genotypes. The molecular detection of ExPEC among these healthy chicken E. coli isolates was performed by PCRs, and the serogroups and antibiotic resistance characteristics of ExPEC were also analyzed. Pulsed-field gel electrophoresis (PFGE) and Multilocus sequence typing (MLST) were used to analyze the genetic relatedness of these ExPEC isolates. We found that the resistance rate for each of the 15 antimicrobials tested among E. coli from white-feather broilers was significantly higher than that from brown-egg layers and that from yellow-feather broilers in live poultry markets (p < 0.05). A total of 22 of the 926 E. coli isolates (2.4%) from healthy chickens were qualified as ExPEC, and the detection rate (7.7%, 6/78) of ExPEC among white-feather broilers was significantly higher than that (1.6%, 6/371) from brown-egg layers and that (2.1%, 10/477) from yellow-feather broilers (p < 0.05). PFGE and MLST analysis indicated that clonal dissemination of these ExPEC isolates was unlikely. Serogroup O78 was the most predominant type among the six serogroups identified in this study, and all the six serogroups had been frequently reported in human ExPEC isolates in many countries. All the 22 ExPEC isolates were multidrug-resistant (MDR) and the resistance rates to ampicillin (100%) and sulfamethoxazole-trimethoprim (100%) were the highest, followed by tetracycline (95.5%) and doxycycline (90.9%). bla_CTX-M was found in 15 of the 22 ExPEC isolates including 10 harboring additional fosfomycin resistance gene fosA3. Notably, plasmid-borne colistin resistance gene mcr-1 was identified in six ExPEC isolates in this study. Worryingly, two ExPEC isolates were found to carry both mcr-1 and bla_NDM, compromising both the efficacies of carbapenems and colistin. The presence of ExPEC isolates in healthy chickens, especially those carrying mcr-1 and/or bla_NDM, is alarming and will pose a threat to the health of consumers. To our knowledge, this is the first report of mcr-1-positive ExPEC isolates harboring bla_NDM from healthy chickens.

Avian Pathogenic Escherichia coli (APEC): An Overview of Virulence and Pathogenesis Factors, Zoonotic Potential, and Control Strategies

Avian pathogenic Escherichia coli (APEC) causes colibacillosis in avian species, and recent reports have suggested APEC as a potential foodborne zoonotic pathogen. Herein, we discuss the virulence and pathogenesis factors of APEC, review the zoonotic potential, provide the current status of antibiotic resistance and progress in vaccine development, and summarize the alternative control measures being investigated. In addition to the known virulence factors, several other factors including quorum sensing system, secretion systems, two-component systems, transcriptional regulators, and genes associated with metabolism also contribute to APEC pathogenesis. The clear understanding of these factors will help in developing new effective treatments. The APEC isolates (particularly belonging to ST95 and ST131 or O1, O2, and O18) have genetic similarities and commonalities in virulence genes with human uropathogenic E. coli (UPEC) and neonatal meningitis E. coli (NMEC) and abilities to cause urinary tract infections and meningitis in humans. Therefore, the zoonotic potential of APEC cannot be undervalued. APEC resistance to almost all classes of antibiotics, including carbapenems, has been already reported. There is a need for an effective APEC vaccine that can provide protection against diverse APEC serotypes. Alternative therapies, especially the virulence inhibitors, can provide a novel solution with less likelihood of developing resistance.

Clinically Relevant Escherichiacoli Isolates from Process Waters and Wastewater of Poultry and Pig Slaughterhouses in Germany

Escherichia coli is frequently associated with multiple antimicrobial resistances and a major cause of bacterial extraintestinal infections in livestock and humans. However, data on the epidemiology of (i) multidrug-resistant (MDR) and (ii) extraintestinal pathogenic E. coli (ExPEC) in poultry and pig slaughterhouses in Germany is currently lacking. Selected E. coli isolates (n = 71) with phenotypic resistance to cephalosporins from two poultry and two pig slaughterhouses expressing high MDR rates (combined resistance to piperacillin, cefotaxime and/or ceftazidime, and ciprofloxacin) of 51.4% and 58.3%, respectively, were analyzed by whole-genome sequencing. They constituted a reservoir for 53 different antimicrobial resistance determinants and were assigned various sequence types, including high-risk clones involved in human infections worldwide. An ExPEC pathotype was detected in 17.1% and 5.6% of the isolates from poultry and pig slaughterhouses, respectively. Worryingly, they were recovered from scalding water and eviscerators, indicating an increased risk for cross-contaminations. Uropathogenic E. coli (UPEC) were detected in the effluent of an in-house wastewater treatment plant (WWTP) of a poultry slaughterhouse, facilitating their further dissemination into surface waters. Our study provides important information on the molecular characteristics of (i) MDR, as well as (ii) ExPEC and UPEC regarding their clonal structure, antimicrobial resistance and virulence factors. Based on their clinical importance and pathogenic potential, the risk of slaughterhouse employees’ exposure cannot be ruled out. Through cross-contamination, these MDR E. coli pathotypes may be introduced into the food chain. Moreover, inadequate wastewater treatment may contribute to the dissemination of UPEC into surface waters, as shown for other WWTPs.

Genetic but No Phenotypic Associations between Biocide Tolerance and Antibiotic Resistance in Escherichia coli from German Broiler Fattening Farms

Biocides are frequently applied as disinfectants in animal husbandry to prevent the transmission of drug-resistant bacteria and to control zoonotic diseases. Concerns have been raised, that their use may contribute to the selection and persistence of antimicrobial-resistant bacteria. Especially, extended-spectrum β-lactamase- and AmpC β-lactamase-producing Escherichia coli have become a global health threat. In our study, 29 ESBL-/AmpC-producing and 64 NON-ESBL-/AmpC-producing E.coli isolates from three German broiler fattening farms collected in 2016 following regular cleaning and disinfection were phylogenetically characterized by whole genome sequencing, analyzed for phylogenetic distribution of virulence-associated genes, and screened for determinants of and associations between biocide tolerance and antibiotic resistance. Of the 30 known and two unknown sequence types detected, ST117 and ST297 were the most common genotypes. These STs are recognized worldwide as pandemic lineages causing disease in humans and poultry. Virulence determinants associated with extraintestinal pathogenic E.coli showed variable phylogenetic distribution patterns. Isolates with reduced biocide susceptibility were rarely found on the tested farms. Nine isolates displayed elevated MICs and/or MBCs of formaldehyde, chlorocresol, peroxyacetic acid, or benzalkonium chloride. Antibiotic resistance to ampicillin, trimethoprim, and sulfamethoxazole was most prevalent. The majority of ESBL-/AmpC-producing isolates carried bla_CTX-M (55%) or bla_CMY-2 (24%) genes. Phenotypic biocide tolerance and antibiotic resistance were not interlinked. However, biocide and metal resistance determinants were found on mobile genetic elements together with antibiotic resistance genes raising concerns that biocides used in the food industry may lead to selection pressure for strains carrying acquired resistance determinants to different antimicrobials.

Genomic characteristics of mcr-1 and blaCTX-M-type in a single multidrug-resistant Escherichia coli ST93 from chicken in China

This study was undertaken to discern the transmission characteristics of mcr-1 and bla_CTX-M-type in one multidrug-resistant Escherichia coli LWY24 from chicken in China. The genetic profiles of LWY24 isolate were determined by conjugation, S1-pulsed-field gel electrophoresis, southern blot hybridization, and whole genome sequencing analysis. Meanwhile, co-transfer of plasmids in LWY24 isolate was screened by dual conjugation assays. The LWY24 isolate was identified as ST93, and harbored 3 conjugative plasmids, pLWY24J-3 (bla_CTX-M-55-bearing IncFⅡ), pLWY24J-mcr-1 (mcr-1-carrying IncI2), and pLWY24J-4 (non-resistance-conferring IncI1), and one nonconjugative plasmid pLWY24 (bla_CTX-M-14-containing IncHI2/IncHI2A). Numerous resistance genes, insertion sequences (especially IS26), and transposons were found in the 4 plasmids, suggesting that horizontal transmission have occurred by plasmid mating, homologous recombination, and transpositions. Under the selection pressure of cefotaxime and colistin or cefotaxime alone, the mcr-1-bearing plasmid and the bla_CTX-M-55-harboring plasmid could be co-transferred at a similar frequency, with 8.00 × 10⁻⁴ or 9.00 × 10⁻⁴ transconjugants per donor cell, respectively. The specific shufflon region in mcr-1-encoding plasmid could generate up to 6 diverse PilV structures, which may further accelerate the horizontal transfer of plasmid. In conclusion, the transmission characteristics of mcr-1 and bla_CTX-M-type in LWY24 isolate could due to clonal spread of ST93, selective pressure of cefotaxime, IS26-mediate homologous recombination and transposition, and the specific shufflon region.

Poultry and Wild Birds as a Reservoir of CMY-2 Producing Escherichia coli: The First Large-Scale Study in Greece

Resistance mediated by β-lactamases is a globally spread menace. The aim of the present study was to determine the occurrence of Escherichia coli producing plasmid-encoded AmpC β-lactamases (pAmpC) in animals. Fecal samples from chickens (n = 159), cattle (n = 104), pigs (n = 214), and various wild bird species (n = 168), collected from different Greek regions during 2018-2020, were screened for the presence of pAmpC-encoding genes. Thirteen E. coli displaying resistance to third-generation cephalosporins and a positive AmpC confirmation test were detected. bla_CMY-2 was the sole pAmpC gene identified in 12 chickens' and 1 wild bird (Eurasian magpie) isolates and was in all cases linked to an upstream ISEcp1-like element. The isolates were classified into five different sequence types: ST131, ST117, ST155, ST429, and ST1415. Four chickens' stains were assigned to ST131, while five chickens' strains and the one from the Eurasian magpie belonged to ST117. Seven pAmpC isolates co-harbored genes conferring resistance to tetracyclines (tetM, tetB, tetC, tetD), 3 carried sulfonamide resistance genes (sulI and sulII), and 10 displayed mutations in the quinolone resistance-determining regions of gyrA (S83L+D87N) and parC (S80I+E84V). This report provides evidence of pAmpC dissemination, describing for the first time the presence of CMY-2 in chickens and wild birds from Greece.

First Evidence of a Relationship Between Female Major Histocompatibility Complex Diversity and Eggshell Bacteria in House Sparrows (Passer domesticus)

Bacteria are known to exert positive and negative influences on animals’ health and fitness. Bacteria, in particular those inhabiting the skin and inner organs of vertebrates, are horizontally or vertically transmitted. Specifically, mothers of bird species can transfer bacterial strains to their offspring when the egg is passing the reproductive tract, as the eggshell rubs against the wall of the uterus. In this context, the female immune system might play an important role in influencing the vertical transmission of bacteria. Here, we investigate the relationship between the major histocompatibility complex (MHC) and cultivable eggshell bacteria originating putatively from the female urogenital tract in a captive population of house sparrows (Passer domesticus). We predict that females with a more variable MHC will transfer fewer bacteria onto the eggshells. Our results show a negative relationship between the number of functional MHC class I alleles and bacteria originating in the urinary tract and growing on a selective medium. This is the first study to find a correlation between female MHC diversity and eggshell bacteria.