Phylogroup and virulence gene association with clinical characteristics of Escherichia coli urinary tract infections from dogs and cats

Genotypic Characterization of Uropathogenic Escherichia coli from Companion Animals: Predominance of ST372 in Dogs and Human-Related ST73 in Cats

Extraintestinal pathogenic Escherichia coli (ExPEC) account for over 80% and 60% of bacterial urinary tract infections (UTIs) in humans and animals, respectively. As shared uropathogenic E. coli (UPEC) strains have been previously reported among humans and pets, our study aimed to characterize E. coli lineages among UTI isolates from dogs and cats and to assess their overlaps with human UPEC lineages. We analysed 315 non-duplicate E. coli isolates from the UT of dogs (198) and cats (117) collected in central Germany in 2019 and 2020 utilizing whole genome sequencing and in silico methods. Phylogroup B2 (77.8%), dog-associated sequence type (ST) 372 (18.1%), and human-associated ST73 (16.6%), were predominant. Other STs included ST12 (8.6%), ST141 (5.1%), ST127 (4.8%), and ST131 (3.5%). Among these, 58.4% were assigned to the ExPEC group and 51.1% to the UPEC group based on their virulence associated gene (VAG) profile (ExPEC, presence of ≥VAGs: papAH and/or papC, sfa/focG, afaD/draBC, kpsMTII, and iutA; UPEC, additionally cnf1 or hlyD). Extended-spectrum cephalosporin (ESC) resistance mediated by extended-spectrum β-lactamases (ESBL) and AmpC-β-lactamase was identified in 1.9% of the isolates, along with one carbapenemase-producing isolate and one isolate carrying a mcr gene. Low occurrence of ESC-resistant or multidrug-resistant (MDR) isolates (2.9%) in the two most frequently detected STs implies that E. coli isolated from UTIs of companion animals are to a lesser extent associated with resistance, but possess virulence-associated genes enabling efficient UT colonization and carriage. Detection of human-related pandemic lineages suggests interspecies transmission and underscores the importance of monitoring companion animals.

Occurrence of Major Human Extraintestinal Pathogenic Escherichia coli Sequence Types Among Diarrheic Pet Animals: A Potential Public Health Threat

Background: Extraintestinal pathogenic Escherichia coli (ExPEC) has become a mounting public health concern. The present study was conducted to address the role of diarrheic pet animals as potential reservoirs for major human ExPEC sequence types (STs). Materials and Methods: Rectal swabs were collected from 145 diarrheic pet animals (75 dogs and 70 cats). Samples were processed for isolation and identification of E. coli by culture methods. Afterward, ExPEC isolates were identified on a molecular basis through detection of ExPEC phylogroups (B2 and D) coupled with carriage of two or more of the virulence genes associated with ExPEC (papAH, papC, sfa/focDE, afa/draBC, iutA, and kpsMT II). ExPEC STs 131, 73, 69, and 95 were identified among ExPEC isolates by quadruplex PCR and tested for their antimicrobial susceptibility. Eventually, two isolates underwent gene sequencing for the phylogenetic analysis. Results: Of 145 pet animals, 16 (11%) E. coli strains were identified as ExPEC, in which 15 (10.3%) isolates belonged to phylogroup B2 and 1 (0.69%) strain belonged to phylogroup D. The major human ExPEC STs were detected in 13 (9%) isolates, whereas the prevalence rates were 5.3% and 12.9% for dogs and cats, respectively. The isolation rates of ExPEC STs were 4.8%, 2.8%, 0.69%, and 0.69% for ST73, ST131, ST95, and ST69, respectively. Regarding the prevalence of virulence genes among ExPEC STs, the most prevalent ones were papC and sfa/focDE (92.3%), followed by papAH (76.9%), iutA (53.8%), afa/draBC (30.8%), and kpsMT II (30.8%). Moreover, 38.5% of the obtained human ExPEC STs were multidrug resistant. The phylogenetic analysis of two ExPEC ST73 gene sequences showed high genetic relatedness to those isolated from humans in different countries. Conclusions: The fecal carriage of major human ExPEC STs among diarrheic dogs and cats poses a potential zoonotic hazard with serious public health implications.

Previous Antibiotic Exposure Reshapes the Population Structure of Infecting Uropathogenic Escherichia coli Strains by Selecting for Antibiotic Resistance over Urovirulence

Antibiotic therapy is the standard of care for urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC). However, previous antibiotic therapy may impart a selective pressure that influences the population structure and pathogenic potential of infecting UPEC strains. Here, we conducted a 3-year study using whole-genome-sequencing analysis and retrospective medical record review to characterize how antibiotic exposure influenced the phenotypic antibiotic resistance, acquired resistome, virulome, and population structure of 88 UTI-causing E. coli strains from dogs. A majority of UTI-associated E. coli strains were from phylogroup B2 and clustered within sequence type 372. Previous antibiotic exposure was associated with a population shift toward UPEC from phylogroups other than the typical urovirulent phylogroup B2. The specific virulence profiles within the accessory virulome that were associated with antibiotic use were elicited by the effect of antibiotics on UPEC phylogenetic structure. Among phylogroup B2, antibiotic exposure increased the quantity of genes within the resistome and the odds of developing reduced susceptibility to at least one antibiotic. Non-B2 UPEC strains harbored a more diverse and greater resistome that conferred reduced susceptibility to multiple antibiotic classes following antibiotic exposure. Collectively, these data suggest that previous antibiotic exposure establishes an environment that provides a selective edge to non-B2 UPEC strains through their diverse and abundant antibiotic resistance genes, despite their lack of urovirulence genes. Our findings highlight the necessity for judicious use of antibiotics as we uncover another mechanism by which antibiotic exposure and resistance can influence the dynamics of bacterial infectious disease. IMPORTANCE Urinary tract infections (UTIs) are one of the most common infections of dogs and humans. While antibiotic therapy is the standard of care for UTIs and other infections, antibiotic exposure may influence the pathogenic profile of subsequent infections. We used whole-genome sequencing and retrospective medical record review to characterize the effect of systemic antibiotic therapy on the resistance, virulence, and population structure of 88 UTI-causing UPEC strains isolated from dogs. Our results indicate that antibiotic exposure alters the population structure of infecting UPEC strains, providing a selective edge for non-B2 phylogroups that harbor diverse and abundant resistance gene catalogues but fewer urovirulence genes. These findings highlight how antibiotic resistance can influence pathogen infection dynamics and have clinical implications for the judicious use of antibiotics for bacterial infections.

Escherichia coli-associated follicular cystitis in dogs: Clinical and pathologic characterization

BACKGROUND

Follicular cystitis is an uncommon inflammatory change in the urinary bladder wall characterized by the formation of tertiary lymphoid structures (TLSs) in the submucosa.

OBJECTIVES

To characterize clinical and pathologic features of follicular cystitis in dogs and to explore in situ distribution and possible role of Escherichia coli as an associated cause.

ANIMALS

Eight dogs diagnosed with follicular cystitis and 2 control dogs.

METHODS

Retrospective descriptive study. Dogs diagnosed with follicular cystitis (macroscopic follicular lesions in the urinary bladder mucosa and histopathologic detection of TLSs in bladder wall biopsies) were identified from medical records. Paraffin embedded bladder wall biopsies were subject to in situ hybridization for E. coli 16SrRNA identification.

RESULTS

Follicular cystitis was diagnosed in large breed (median weight 24.9 kg, interquartile range [IQR] 18.8-35.4 kg) female dogs with a history of chronic recurrent urinary tract infections (UTIs; median duration of clinical signs 7 months, IQR 3-17 months; median number of previous UTIs 5, IQR 4-6). Positive E. coli 16SrRNA signal was detected within developing, immature and mature TLSs in 7/8 dogs, through submucosal stroma in 8/8 dogs and within the urothelium in 3/8 dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Chronic inflammation associated with an intramural E. coli infection in the urinary bladder wall represents a possible triggering factor for the development of follicular cystitis.

An Emerging Lineage of Uropathogenic Extended Spectrum β-Lactamase Escherichia coli ST127

Uropathogenic Escherichia coli (UPEC) is one of the most common causes of urinary tract infections. Here, we report for the first time the whole-genome sequencing (WGS) and analysis of four extended-spectrum β-lactamase (ESBL), UPEC sequence type (ST) 127 isolates that were recovered from patients in five hospitals in Armenia from January to August of 2019. A phylogenetic comparison revealed that our isolates were closely related to each other by their core and accessory genomes, despite having been isolated from different regions and hospitals in Armenia. We identified unique genes in our isolates and in a closely related isolate recovered in France. The unique genes (hemolysin E virulence gene, lactate utilization operon lutABC, and endonuclease restriction modification operon hsdMSR) were identified in three separate genomic regions that were adjacent to prophage genes, including one region containing the TonB-dependent iron siderophore receptor gene ireA, which was only found in 5 other ST127 isolates from the European Nucleotide Archive (ENA). We further identified that these isolates possessed unique virulence and metabolic genes and harbored antibiotic resistance genes, including the ESBL genes bla_CTX-M-3 (n = 3), bla_CTX-M-236 (n = 1), and bla_TEM-1 (n = 1), in addition to a quinolone resistance protein gene qnrD1 (n = 1), which was absent in the ST127 isolates obtained from the ENA. Moreover, a plasmid replicon gene IncI2 (n = 1) was unique to ARM88 of the Armenian isolates. Our findings demonstrate that at the time of this study, E. coli ST127 was a cause of urinary tract infections in patients in different regions of Armenia, with a possibility of cross-country transmission between Armenia and France. IMPORTANCE Whole-genome sequencing studies of pathogens causing infectious diseases are seriously lacking in Armenia, hampering global efforts to track, trace and contain infectious disease outbreaks. In this study, we report for the first-time the whole-genome sequencing and analysis of ESBL UPEC ST127 isolates recovered from hospitalized patients in Armenia and compare them with other E. coli ST127 retrieved from the ENA. We found close genetic similarities of the Armenian isolates, indicating that E. coli ST127 was potentially a dominant lineage causing urinary tract infections in Armenia. Furthermore, we identified unique genes that were horizontally acquired in the clusters of Armenian and French isolates that were absent in other ST127 isolates obtained from the ENA. Our findings highlight a possible cross-country transmission between Armenia and France and the idea that the implementation of WGS surveillance could contribute to global efforts in tackling antibiotic resistance, as bacteria carrying antimicrobial resistance (AMR) genes do not recognize borders.

Antimicrobial Resistance and Prevalence of Extended Spectrum β-Lactamase-Producing Escherichia coli from Dogs and Cats in Northeastern China from 2012 to 2021

(1) Background: there has been a growing concern about pet-spread bacterial zoonosis in recent years. This study aimed to investigate the trend in drug-resistance of canine Escherichia coli isolates in northeast China between 2012-2021 and the differences in drug-resistance of E. coli of different origins in 2021. (2) Methods: E. coli were isolated from feces or anal swab samples from dogs and cats, and their antibiotic susceptibility profiles and phylogenetic grouping were identified. PCR was applied on the extended spectrum β-lactamase (ESBL) E. coli for antibiotic resistance genes. (3) Results: five hundred and fifty-four E. coli isolates were detected in 869 samples (63.75%). The multidrug resistance (MDR) rates of E. coli in pet dogs showed a decreasing trend, but working dogs showed the opposite trend. Resistance genes blaCTX-M and blaCTX-M+TEM were dominant among the ESBL producers (n = 219). The consistency between the resistance phenotypes and genes was high except for fluoroquinolone-resistant ESBL E. coli. All ESBL E. coli-carrying blaNDM were isolated from working dogs, and one of the strains carried mcr-1 and blaNDM-4. Phylogroup B2 was the dominant group in pet cats, and more than half of the isolates from companion cats were ESBL E. coli. (4) Conclusions: the measures taken to reduce resistance in China were beginning to bear fruit. Companion cats may be more susceptible to colonization by ESBL E. coli. The problem of resistant bacteria in working dogs and pet cats warrants concern.

Pathogenomics and clinical recurrence influence biofilm capacity of Escherichia coli isolated from canine urinary tract infections

Biofilm formation enhances bacteria’s ability to colonize unique niches while protecting themselves from environmental stressors. Escherichia coli that colonize the urinary tract can protect themselves from the harsh bladder environment by forming biofilms. These biofilms promote persistence that can lead to chronic and recurrent urinary tract infections (UTI). While biofilm formation is frequently studied among urinary E. coli, its association with other pathogenic mechanisms and adaptations in certain host populations remains poorly understood. Here we utilized whole genome sequencing and retrospective medical record analysis to investigate associations between the population structure, phenotypic resistance, resistome, virulome, and patient demographic and clinical findings of 104 unique urinary E. coli and their capacity to form biofilms. We show that population structure including multilocus sequence typing and Clermont phylogrouping had no association with biofilm capacity. Among clinical factors, exposure to multiple antibiotics within that past 30 days and a clinical history of recurrent UTIs were positively associated with biofilm formation. In contrast, phenotypic antimicrobial reduced susceptibility and corresponding acquired resistance genes were negatively associated with biofilm formation. While biofilm formation was associated with increased virulence genes within the cumulative virulome, individual virulence genes did not influence biofilm capacity. We identified unique virulotypes among different strata of biofilm formation and associated the presence of the tosA/R-ibeA gene combination with moderate to strong biofilm formation. Our findings suggest that E. coli causing UTI in dogs utilize a heterogenous mixture of virulence genes to reach a biofilm phenotype, some of which may promote robust biofilm capacity. Antimicrobial use may select for two populations, non-biofilm formers that maintain an arsenal of antimicrobial resistance genes to nullify treatment and a second that forms durable biofilms to avoid therapeutic insults.

Demonstrating the utility of Escherichia coli asymptomatic bacteriuria isolates’ virulence profile towards diagnosis and management—A preliminary analysis

Asymptomatic bacteriuria (ASB) caused by Escherichia coli (E. coli) is a significant condition associated with pregnancy and is considered as prognostic for the development of symptomatic urinary tract infection (UTI). However, treating all ASB increases the use of antibiotics and leads to the development of multidrug resistance (MDR). Therefore, this study aimed to identify the distribution of UPEC associated virulence genes and antibiotic susceptibility among phylogroups of E. coli isolated from ASB in pregnancy. Moreover, the gene expression of selected virulence genes was also compared among two E. coli isolates (with different pathogenic potential) to determine its pathogenicity. One hundred and sixty E. coli isolates from midstream urine samples of pregnant women with ASB were subjected to PCR-based detection for its phylogroups and virulence genes. The antibiotic susceptibility of isolated strains was determined by the disc diffusion method. Expression of the virulence genes were determined through microarray analysis and quantitative Real-Time PCR. The prevalence of ASB in this study was 16.1%. Within ASB isolates, the occurrence of phylogroup B2 was the highest, and isolates from this group harboured most of the virulence genes studied. Overall, the most identified virulence genes among all phylogroups in descending order were fimH, chuA, kpsMTII, usp, fyuA, hlyA, iroN, cnf, papC, sfa, ompT, and sat. In this study, higher resistance to antibiotics was observed for ampicillin (77.5%), amoxicillin-clavulanate (54.4%), trimethoprim-sulfamethoxazole (46.9%) and amikacin (43.8%) compared to the other tested antibiotics and 51.9% of the tested isolates were MDR. Furthermore, hierarchical clustering and gene expression analysis demonstrated extreme polarization of pathogenic potential of E. coli causing ASB in pregnancy necessitating the need for bacterial isolate focused approach towards treatment of ASB.

Antibiotic Resistant and Biofilm-Associated Escherichia coli Isolates from Diarrheic and Healthy Dogs

Bacteria isolated from companion animals are attracting concerns in a view of public health including antimicrobial resistance and biofilm development, both contributing to difficult-to-treat infections. The purpose of this study was to evaluate the minimum inhibitory concentrations (MIC) of 18 antibiotics in Escherichia coli isolated from two groups of dogs (healthy and diarrheic). Isolates were classified into phylogroups, examined for the presence of resistance genes and biofilm-formation capacity. In healthy dogs, phylogenetic analysis showed that 47.37% and 34.22% of E. coli isolates belonged to commensal groups (A; B1) in contrast to diarrheic dogs; 42.2% of isolates were identified as the B2 phylogroup, and these E. coli bacteria formed a stronger biofilm. The results of healthy dogs showed higher MIC levels for tetracycline (32 mg/L), ampicillin (64 mg/L), ciprofloxacin (8 mg/L) and trimethoprim-sulphonamide (8 mg/L) compared to clinical breakpoints. The most detected gene encoding plasmid-mediated resistance to quinolones in the healthy group was qnrB, and in dogs with diarrhea, qnrS. The resistance genes were more frequently detected in healthy dogs. The presence of the integron int1 and the transposon tn3 increases the possibility of transfer of many different cassette-associated antibiotic-resistance genes. These results suggest that dogs could be a potential reservoir of resistance genes.

A review of the taxonomy, genetics, and biology of the genus Escherichia and the type species Escherichia coli

Historically, bacteriologists have relied heavily on biochemical and structural phenotypes for bacterial taxonomic classification. However, advances in comparative genomics have led to greater insights into the remarkable genetic diversity within the microbial world, and even within well-accepted species such as Escherichia coli. The extraordinary genetic diversity in E. coli recapitulates the evolutionary radiation of this species in exploiting a wide range of niches (i.e., ecotypes), including the gastrointestinal system of diverse vertebrate hosts as well as non-host natural environments (soil, natural waters, wastewater), which drives the adaptation, natural selection, and evolution of intragenotypic conspecific specialism as a strategy for survival. Over the last few years, there has been increasing evidence that many E. coli strains are very host (or niche)-specific. While biochemical and phylogenetic evidence support the classification of E. coli as a distinct species, the vast genomic (diverse pan-genome and intragenotypic variability), phenotypic (e.g., metabolic pathways), and ecotypic (host-/niche-specificity) diversity, comparable to the diversity observed in known species complexes, suggest that E. coli is better represented as a complex. Herein we review the taxonomic classification of the genus Escherichia and discuss how phenotype, genotype, and ecotype recapitulate our understanding of the biology of this remarkable bacterium.

Genetic Characterization of AmpC and Extended-Spectrum Beta-Lactamase Phenotypes in Escherichia coli and Salmonella From Alberta Broiler Chickens

Horizontal gene transfer is an important mechanism which facilitates bacterial populations in overcoming antimicrobial treatment. In this study, a total of 120 Escherichia coli and 62 Salmonella enterica subsp. enterica isolates were isolated from broiler chicken farms in Alberta. Fourteen serovars were identified among Salmonella isolates. Thirty one percent of E. coli isolates (37/120) were multiclass drug resistant (resistant to ≥ 3 drug classes), while only about 16% of Salmonella isolates (10/62) were multiclass drug resistant. Among those, eight E. coli isolates had an AmpC-type phenotype, and one Salmonella isolate had an extended-spectrum beta-lactamase (ESBL)-type beta-lactamase phenotype. We identified both AmpC-type (bla_CMY-2) and ESBL-type (bla_TEM) genes in both E. coli and Salmonella isolates. Plasmids from eight of nine E. coli and Salmonella isolates were transferred to recipient strain E. coli J53 through conjugation. Transferable plasmids in the eight E. coli and Salmonella isolates were also transferred into a lab-made sodium azide-resistant Salmonella recipient through conjugation. The class 1 integrase gene, int1, was detected on plasmids from two E. coli isolates. Further investigation of class 1 integron cassette regions revealed the presence of an aadA gene encoding streptomycin 3’’-adenylyltransferase, an aadA1a/aadA2 gene encoding aminoglycoside 3’’-O-adenyltransferase, and a putative adenylyltransferase gene. This study provides some insight into potential horizontal gene transfer events of antimicrobial resistance genes between E. coli and Salmonella in broiler chicken production.

Molecular assessment of antimicrobial resistance and virulence in multi drug resistant ESBL-producing Escherichia coli and Klebsiella pneumoniae from food fishes, Assam, India

The present study investigated the prevalence of Extended-Spectrum Beta Lactamase (ESBL) -producing E. coli and K. pneumoniae from the food fishes in retail markets in Assam, India. A total of 54 ESBL-producing E. coli and 12 K. pneumoniae isolates were recovered from 79 fish samples and were analyzed for antimicrobial resistance genes (ARGs) and virulence genes. E. coli isolates were categorized as multi drug resistant with resistance up to 12 different antibiotics with multiple antibiotic resistances (MAR) index ranging from 0.26 to 0.63. In E. coli, 100% resistance to cefotaxime along with 6% resistance to ceftazidime (third-generation cephalosporins) was observed. Moreover, 85% of the E. coli isolates were resistant to cefepime, a fourth-generation cephalosporin. K. pneumoniae showed resistance to 11 different antibiotics with MAR index value ranging from 0.21 to 0.57. All K. pneumoniae isolates showed 100% resistance to cefotaxime, 67% resistance to ceftazidime and 75% resistance to cefepime. Molecular characterization of ARGs revealed the presence of CTX-M group 1(CTX-M-15) in almost all E. coli isolates (98%, n = 53) and 100% in K. pneumoniae. A combination of uniplex and multiplex PCRs revealed fewer ARGs in E. coli isolates, with each isolate carrying 3 to 5 genes (tetA, dfrA1, sul1, sul2, qnrB, qnrS, aac(6')-Ib-cr). Majority of the E. coli were assigned to low-virulence phylogroup B1 and A while 8% of them belonged to pathogenic phylogroup D. 31 unique genetic profiles were identified for E. coli isolates by Pulsed-Field Gel Electrophoresis (PFGE) typing. K. pneumoniae isolates were highly diverse with 11 unique genetic profiles and a substantial ARG profile (bla_TEM, bla_SHV, bla_OXA-1-like, tetA, strA, strB, dfrA1, sul1, sul2, qnrB, qnrS, aac(6')-Ib-cr, oqxA, oqxB). The frequency of ARGs ranged between 4 and 11. All K. pneumoniae isolates belonged to capsular serotype with wzi gene. Virulence gene iutA was prominent in all isolates while ybtS and kfu were confirmed in two isolates. Our findings raise concerns that fishes bought for consumption may serve as potential reservoirs of AMR genes and pose serious threat to public health. The study emphasizes the need for extensive surveillance of resistant strains in aquaculture and related settings, their in-depth analysis of population structure and transmission dynamics.

Comprehensive phenotypic and genotypic characterization and comparison of virulence, biofilm, and antimicrobial resistance in urinary Escherichia coli isolated from canines

Urinary tract infections (UTIs) affect nearly half of women and an estimated 14 % of the canine companion animal population at least once in their lifetime. As with humans, Escherichia coli is the most commonly isolated bacteria from canine UTIs and infections are dominated by specific phylogenetic groups with notable virulence attributes. In this study, we evaluated uropathogenic E. coli (UPEC) (n = 69) isolated from canine UTIs phenotypically and genotypically for virulence factors, biofilm formation and antimicrobial resistance profiles. Biofilm formation in UPEC strains was positively associated with common virulence factors including papG (p = 0.006), fimH (p < 0.0001), sfaS (p = 0.004), focA (p = 0.004), cnf-1 (p = 0.009) and hlyA (p = 0.006). There was a negative association between biofilm formation and phenotypic antimicrobial resistance for ampicillin (p < 0.0004), ciprofloxacin (p < 0.0001), and trimethoprim-sulfamethoxazole (p < 0.02), as well as multidrug resistance (isolates resistant to ≥ 3 classes of antimicrobials) (p < 0.0002), and the presence of extended spectrum beta-lactamase (ESBL)-producing genes (p < 0.05). In conclusion, UPECs isolated from clinical cases of canine UTIs show a broad negative association between antimicrobial resistance and biofilm formation, and this observation is supported both by phenotypic and genotypic endpoints. As the biofilm formation may result in antimicrobial tolerance, this could be a secondary evasive tactic of UPEC lacking traditional antimicrobial resistance traits. This observation is important for veterinary practitioners to consider when treating puzzling chronic intractable and/or recurrent cases of UTI that appear to be susceptible to antimicrobial therapy via traditional antimicrobial susceptibility testing (AST) methods.

Current status of resistance to antibiotics in the Democratic Republic of the Congo: A review

A review of literature was conducted to assess the prevalence and mechanisms of antibiotic resistance to date, mainly to β-lactam antibiotics, cephalosporins, carbapenems, colistin, and tigecycline in the Democratic Republic of the Congo (DRC). English and French publications were listed and analysed using PubMed/Medline, Google Scholar, and African Journals database between 1 January 1990 and 31 December 2019. For the 30 published articles found: (1) bacterial resistance to antibiotics concerned both Gram-negative and Gram-positive bacteria; (2) multidrug resistance prevalence was the same in half of Streptococcus pneumoniae isolates; (3) a worrying prevalence of methicillin-resistant Staphylococcus aureus (MRSA) was noted, which is associated with co-resistance to several other antibiotics; and (4) resistance to third-generation cephalosporins was very high in Enterobacteriaceae, mainly because of bla_CTX-M-1 group and bla_SHV genes. Data on carbapenem and colistin resistance were not available in DRC until recently. Further work is required to set up a surveillance system for antibiotic resistance in DRC.

Genomic analysis of fluoroquinolone-susceptible phylogenetic group B2 extraintestinal pathogenic Escherichia coli causing infections in cats

Extraintestinal pathogenic Escherichia coli (ExPEC) can cause urinary tract and other types of infection in cats, but the relationship of cat ExPEC to human ExPEC remains equivocal. This study investigated the prevalence of ExPEC-associated sequence types (STs) from phylogenetic group B2 among fluoroquinolone-susceptible cat clinical isolates. For this, 323 fluoroquinolone-susceptible cat clinical E. coli isolates from Australia underwent PCR-based phylotyping and random amplified polymorphic DNA analysis to determine clonal relatedness. Of the 274 group B2 isolates, 53 underwent whole genome sequencing (WGS), whereas 221 underwent PCR-based screening for (group B2) sequence type complexes (STc) STc12, STc73, ST131, and STc372. Group B2 was the dominant phylogenetic group (274/323, 85 %), whereas within group B2 ST73 dominated, according to both WGS (43 % of 53; followed by ST127, ST12, and ST372 [4/53, 8 % each]) and ST-specific PCR (20 % of 221). In WGS-based comparisons of cat and reference human ST73 isolates, cat isolates had a relatively conserved virulence gene profile but were phylogenetically diverse. Although in the phylogram most cat and human ST73 isolates occupied host species-specific clusters within serotype-specific clades (O2:H1, O6:H1, O25:H1, O50/O2:H1), cat and human isolates were intermingled within two serotype-specific clades: O120:H31 (3 cat and 2 human isolates) and O22:H1 (3 cat and 5 human isolates). These findings confirm the importance of human-associated group B2 lineages as a cause of urinary tract infections in cats. The close genetic relationship of some cat and human ST73 strains suggests bi-directional transmission may be possible.

Genomic Characterization of Antibiotic Resistant Escherichia coli Isolated From Domestic Chickens in Pakistan

Poultry husbandry is important for the economic health of Pakistan, but the Pakistani poultry industry is negatively impacted by infections from Escherichia coli. We performed Illumina whole genome sequencing on 92 E. coli isolates obtained from the livers of deceased chickens originating in five Pakistani geographical regions. Our analysis indicates that the isolates are predominantly from the B1 and A clade and harbor a diverse number of antibiotic resistance and virulence genes, with no linkage between phylogeny and antibiotic resistance gene presence but some association between phylogeny and virulence gene and SNP presence for the B1 and E phylogroups. The colistin resistance gene mcr-1 and the quinolone resistance gene qnrS1 were both found in 13/92 isolates. Alarmingly, 82/92 of the E. coli strains characterized in this study are multidrug resistant with 100% (92/92) resistance to lincomycin, 81.5% (75/92) to streptomycin, 79.3% (73/92) to ampicillin and 66.3% (61/92) to ciprofloxacin. These results provide a high-resolution analysis of poultry-associated E. coli isolates in an area with a high endemic burden of antibiotic resistance. Surveillance of antibiotic resistance in poultry associated E. coli isolates is an important pillar of the One Health concept to integrate analysis of potential pathogens in human, animal, and environmental niches.

Transmission of antimicrobial resistant non-O157 Escherichia coli at the interface of animal-fresh produce in sustainable farming environments

The interaction of typical host adapted enteric bacterial pathogens with fresh produce grown in fields is complex. These interactions can be more pronounced in co-managed or sustainable farms where animal operations are, by design, close to fresh produce, and growers frequently move between the two production environments. The primary objectives of this study were to 1) determine the transmission of STEC or enteric pathogens from small and large animal herds or operations to fresh produce on sustainable farms in TN and NC, 2) identify the possible sources that impact transmission of AMR E. coli, specifically STEC on these systems, and 3) WGS to characterize recovered E. coli from these sources. Samples were collected from raw and composted manure, environment, and produce sources. The serotype, virulence, and genotypic resistance profile were determined using the assembled genome sequences sequenced by Illumina technology. Broth microdilution was used to determine the antimicrobial susceptibility of each isolate against a panel of fourteen antimicrobials. The prevalence of E. coli increased during the summer season for all sources tested. ParSNP trees generated demonstrated that the transmission of AMR E. coli is occurring between animal feeding operations and fresh produce. Ten isolates were identified as serotype O45, a serotype that is associated with the "Big Six" group that is frequently linked with foodborne outbreaks caused by non-O157 E. coli. However, these isolates did not possess the stx gene. The highest frequency of resistance was detected against streptomycin (n = 225), ampicillin (n = 190) and sulfisoxazole FIS (n = 140). A total of 35 (13.7%) isolates from two TN farms were positive for the blaCMY (n = 5) and blaTEM (n = 32) genes. The results of this study show the potential of AMR E. coli transmission between animal feeding operations and fresh produce, and more studies are recommended to study this interaction and prevent dissemination in sustainable farming systems.

Genetic structure, antimicrobial resistance and frequency of human associated Escherichia coli sequence types among faecal isolates from healthy dogs and cats living in Canberra, Australia

Extraintestinal pathogenic Escherichia coli (ExPEC) cause clinical infections in humans. Understanding the evolution and dissemination of ExPEC strains via potential reservoirs is important due to associated morbidity, health care costs and mortality. To further understanding this survey has examined isolates recovered from the faeces of 221 healthy dogs and 427 healthy cats. The distribution of phylogroups varied with host species, and depended on whether the animal was living in a shelter or a home. The human associated STs 69, 73, 95, 131 and 127 were prevalent, with 30.5% of cat isolates and 10.3% of dog isolates representing these ExPEC sequence types. Resistance to the antibiotics ampicillin and tetracycline was common, but resistance to other antimicrobials was negligible.

The relation of phylogroups, serogroups, virulence factors and resistance pattern of Escherichia coli isolated from children with septicemia

The characterization of virulent and drug-resistant Escherichia coli strains helps to control and provide more accurate information regarding infection and eradication. The aim of this study was to determine the relationship between antibiotic susceptibility, phylogroups and virulence factors of E. coli isolates from children with septicaemia. One hundred dereplicated E. coli isolates were collected from paediatric patients with septicaemia in five hospitals in Tehran (May 2015 to May 2018). The antibiotic susceptibility of isolates was performed as per the 2016 guidelines of the Clinical and Laboratory Standards Institute. Extended-spectrum β-lactamases and carbapenemase genes, phylogroups, serogroups and virulence encoding genes were detected by PCR. Phylogroup B2 was dominant (40%) among strains, followed by phylogroups D (30%), A (8%) and B1 (7%). CTX-M1 was significantly higher in the B2 group (n = 21, p 0.001). Furthermore, the virulence genes iutA (n = 27, p 0.002), csgA (n = 39, p <0.001), kpsMII (n = 39, p 0.002), ibeA (n = 4, p 0.004), vat (n = 5, p 0.003), traT (n = 24, p <0.001), sat (n = 12, p 0.001) and hlyA (n = 33, p <0.001) showed significantly higher rates in phylogroup B2. Three O25/CTXM1/OXA-48 and cnf, iutA, csgA and traT positive isolates belonged to phylogroup B2. Pulsed-field gel electrophoresis analysis showed 85% similarity among 25% of isolates. More than half of the isolates were multidrug-resistant E. coli. A significant relation was observed among iutA, csgA, kpsMII, ibeA, vat, traT, sat and hlyA genes and phylogroup B2. The characterization of virulent and drug-resistant strains helps control and properly eliminate infections. There was no genetic relation among strains in the pulsed-field gel electrophoresis pattern.

Antimicrobial Resistance in Escherichia coli

Multidrug resistance in Escherichia coli has become a worrying issue that is increasingly observed in human but also in veterinary medicine worldwide. E. coli is intrinsically susceptible to almost all clinically relevant antimicrobial agents, but this bacterial species has a great capacity to accumulate resistance genes, mostly through horizontal gene transfer. The most problematic mechanisms in E. coli correspond to the acquisition of genes coding for extended-spectrum β-lactamases (conferring resistance to broad-spectrum cephalosporins), carbapenemases (conferring resistance to carbapenems), 16S rRNA methylases (conferring pan-resistance to aminoglycosides), plasmid-mediated quinolone resistance (PMQR) genes (conferring resistance to [fluoro]quinolones), and mcr genes (conferring resistance to polymyxins). Although the spread of carbapenemase genes has been mainly recognized in the human sector but poorly recognized in animals, colistin resistance in E. coli seems rather to be related to the use of colistin in veterinary medicine on a global scale. For the other resistance traits, their cross-transfer between the human and animal sectors still remains controversial even though genomic investigations indicate that extended-spectrum β-lactamase producers encountered in animals are distinct from those affecting humans. In addition, E. coli of animal origin often also show resistances to other-mostly older-antimicrobial agents, including tetracyclines, phenicols, sulfonamides, trimethoprim, and fosfomycin. Plasmids, especially multiresistance plasmids, but also other mobile genetic elements, such as transposons and gene cassettes in class 1 and class 2 integrons, seem to play a major role in the dissemination of resistance genes. Of note, coselection and persistence of resistances to critically important antimicrobial agents in human medicine also occurs through the massive use of antimicrobial agents in veterinary medicine, such as tetracyclines or sulfonamides, as long as all those determinants are located on the same genetic elements.