Comparative Genome Analysis of an Extensively Drug-Resistant Isolate of Avian Sequence Type 167 Escherichia coli Strain Sanji with Novel In Silico Serotype O89b:H9

Multidrug-resistant Escherichia coli isolated from patients and surrounding hospital environments in Bangladesh: A molecular approach for the determination of pathogenicity and resistance

Extended spectrum β-lactamase producing Escherichia coli (ESBL E. coli) is a primary concern for hospital and community healthcare settings, often linked to an increased incidence of nosocomial infections. This study investigated the characteristics of ESBL E. coli isolated from hospital environments and clinical samples. In total, 117 ESBL E. coli isolates were obtained. The isolates were subjected to molecular analysis for the presence of resistance and virulence genes, antibiotic susceptibility testing, quantitative adherence assay, ERIC-PCR for phylogenetic analysis and whole genome sequencing of four highly drug resistant isolates. Out of the 117 isolates, 68.4% were positive for blaCTX-M, 39.3% for blaTEM, 30.8% for blaNDM-1, 13.7% for blaOXA and 1.7% for blaSHV gene. Upon screening for diarrheagenic genes, no isolates were found to harbour any of the tested genes. In the case of extraintestinal pathogenic E. coli (ExPEC) virulence factors, 7.6%, 11%, 5.9%, 4.3% and 21.2% of isolates harbored the focG, kpsMII, sfaS, afa and iutA genes, respectively. At a temperature of 25°C, 14.5% of isolates exhibited strong biofilm formation with 21.4% and 28.2% exhibiting moderate and weak biofilm formation respectively, whereas 35.9% were non-biofilm formers. On the other hand at 37°C, 2.6% of isolates showed strong biofilm formation with 3.4% and 31.6% showing moderate and weak biofilm formation respectively, whereas, 62.4% were non-biofilm formers. Regarding antibiotic susceptibility testing, all isolates were found to be multidrug-resistant (MDR), with 30 isolates being highly drug resistant. ERIC-PCR resulted in 12 clusters, with cluster E-10 containing the maximum number of isolates. Hierarchical clustering and correlation analysis revealed associations between environmental and clinical isolates, indicating likely transmission and dissemination from the hospital environment to the patients. The whole genome sequencing of four highly drug resistant ExPEC isolates showed the presence of various antimicrobial resistance genes, virulence factors and mobile genetic elements, with isolates harbouring the plasmid incompatibility group IncF (FII, FIB, FIA). The sequenced isolates were identified as human pathogens with a 93.3% average score. This study suggests that ESBL producing E. coli are prevalent in the healthcare settings of Bangladesh, acting as a potential reservoir for AMR bacteria. This information may have a profound effect on treatment, and improvements in public healthcare policies are a necessity to combat the increased incidences of hospital-acquired infections in the country.

An ST131 clade and a phylogroup A clade bearing an O101-like O-antigen cluster predominate among bloodstream Escherichia coli isolates from South-West Nigeria hospitals

Escherichia coli bloodstream infections are typically attributed to a limited number of lineages that carry virulence factors associated with invasiveness. In Nigeria, the identity of circulating clones is largely unknown and surveillance of their antimicrobial resistance has been limited. We verified and whole-genome sequenced 68 2016-2018 bloodstream E. coli isolates from three sentinel sites in South-Western Nigeria and susceptibility tested 67 of them. Resistance to antimicrobials commonly used in Nigeria was high, with 67 (100 %), 62 (92.5 %), 53 (79.1 %) and 37 (55.2 %) showing resistance to trimethoprim, ampicillin, ciprofloxacin and aminoglycosides, respectively. Thirty-five (51 %) isolates carried extended-spectrum β-lactamase genes and 32 (91 %) of these were multidrug resistant. All the isolates were susceptible to carbapenems and colistin. The strain set included globally disseminated high-risk clones from sequence type (ST)12 (2), ST131 (12) and ST648 (4). Twenty-three (33.8 %) of the isolates clustered within two clades. The first of these consisted of ST131 strains, comprising O16:H5 and O25:H4 sub-lineages. The second was an ST10-ST167 complex clade comprising strains carrying O-antigen and capsular genes of likely Klebsiella origin, identical to those of avian pathogenic E. coli Sanji, and serotyped in silico as O89, O101 or ONovel32, depending on the tool used. Four temporally associated ST90 strains from one sentinel were closely related enough to suggest that at least some of them represented a retrospectively detected outbreak cluster. Our data implicate a broad repertoire of E. coli isolates associated with bloodstream infections in South-West Nigeria. Continued genomic surveillance is valuable for tracking clones of importance and for outbreak identification.

Genomics and pathotypes of the many faces of Escherichia coli

Escherichia coli is the most researched microbial organism in the world. Its varied impact on human health, consisting of commensalism, gastrointestinal disease, or extraintestinal pathologies, has generated a separation of the species into at least eleven pathotypes (also known as pathovars). These are broadly split into two groups, intestinal pathogenic E. coli (InPEC) and extraintestinal pathogenic E. coli (ExPEC). However, components of E. coli's infinite open accessory genome are horizontally transferred with substantial frequency, creating pathogenic hybrid strains that defy a clear pathotype designation. Here, we take a birds-eye view of the E. coli species, characterizing it from historical, clinical, and genetic perspectives. We examine the wide spectrum of human disease caused by E. coli, the genome content of the bacterium, and its propensity to acquire, exchange, and maintain antibiotic resistance genes and virulence traits. Our portrayal of the species also discusses elements that have shaped its overall population structure and summarizes the current state of vaccine development targeted at the most frequent E. coli pathovars. In our conclusions, we advocate streamlining efforts for clinical reporting of ExPEC, and emphasize the pathogenic potential that exists throughout the entire species.

Whole genome sequencing and characteristics of extended-spectrum beta-lactamase producing Escherichia coli isolated from poultry farms in Banaskantha, India

Worldwide dissemination of extended-spectrum -lactamase (ESBL)-producing Escherichia coli constitutes an emerging global health issue, with animal food products contributing as potential reservoirs. ESBL E. coli infection is associated with the high mortality and mobility rate in developing countries due to less susceptibility to antibiotics. The present study aimed to elucidate the molecular characteristics and sequence-based analysis of ESBL E. coli in the Gujarat state of India. This study included 108 E. coli strains were isolated from different poultry farms (broiler and layer) in the Banaskantha District. PCR was employed to identify genotypic ESBL-producing antimicrobial resistance genes. Overall, a high occurrence of ESBL genes was found in poultry farms due to the high usage of antimicrobials. The PCR analysis revealed that 79.62% of isolates were detected positive with one or more ESBL genes. Among them, bla_TEM (63.88%) was found to be the predominant genotype, followed by bla_SHV (30.55%) and bla_OXA (28.70%). In the bla_CTX-M group, a higher occurrence was observed in bla_CTX-M-9 (23.14%), followed by bla_CTX-M-2 (24.07%) and bla_CTX-M-1 (22.22%). We used the whole-genome sequencing (WGS) method to evaluate the antimicrobial resistance genes, virulence factors, single nucleotide polymorphisms (SNPs), plasmid replicons, and plasmid-mediated AMR genes of one ESBL E. coli isolated. We examined the genetic relatedness of a human pathogenic E. coli strain by comparing its sequence with the broad geographical reference E. coli sequences. Escherichia coli ST 681 was determined using multi-locus sequence typing. We compared our findings to the reference sequence of Escherichia coli str. K- 12 substr. MG1655. We found 24,937 SNPs with 21,792 in the genic region, 3,145 in the intergenic region, and six InDels across the genome. The WGS analysis revealed 46 antimicrobial resistance genes and seven plasmid-mediated AMR genes viz., tetA, qnrS1, dfrA14, sul2, aph(3”)-lb, aph(6)-ld, and Aph(3’)-la. The ST 681 was found to have Cib, traT, and terC virulence factors and two plasmid replicons, IncFII(pHN7A8) and IncI1-I(Alpha). This study revealed a higher occurrence of ESBL E. coli detected in poultry.

High prevalence of multiple antibiotic resistance in clinical E. coli isolates from Bangladesh and prediction of molecular resistance determinants using WGS of an XDR isolate

Multi-drug-resistance (MDR) is a severe public health concern worldwide, and its containment is more challenging in developing countries due to poor antimicrobial resistance (AMR) surveillance and irrational use of antibiotics. The current study investigated 100 clinical E. coli isolates and revealed that 98% of them were MDR. PCR analysis using 25 selected isolates showed the predominance of metallo-β-lactamase gene bla_NDM (80%) and ESBL genes bla_OXA (48%) and bla_CTX-M-15 (32%). The AmpC gene was detected in 68% of the isolates, while 32% was tetC positive. Notably, 34% of the isolates were resistant to carbapenem. Whole genome sequence (WGS) analysis of an extensively drug-resistant (XDR) isolate (L16) revealed the presence of the notorious sequence type 131 responsible for multi-drug-resistant infections, multiple antibiotic resistance genes (ARGs), virulence genes, and mobile genetic elements that pose risks to environmental transmission. Our results indicate that MDR is alarmingly increasing in Bangladesh that critically limits the treatment option against infections and contributes to further aggravation to the prevailing situation of MDR worldwide. The findings of this study will be valuable in designing sustainable strategies to contain MDR in the region.

Molecular epidemiology of NDM-5-producing Escherichia coli high-risk clones identified in two Italian hospitals in 2017-2019

Between November 2018 and October 2019, carbapenem-resistant Enterobacterales carrying New Delhi Metallo-β-lactamase (NDM) caused one of the largest and persistent outbreaks occurred in Italy and intensified surveillance measures have been taken in all Italian hospitals. In this study we analyzed NDM-5- producing Escherichia coli identified in 2 hospitals of the Lazio region in Italy. Epidemiological and microbiological data demonstrated that in 2018-2019 the NDM-5-producing high-risk E. coli ST167 clone circulated in patients from both hospitals. In 2019, another NDM-5-producing E. coli clone, identified by MLST as ST617 was introduced in one of the 2 hospitals and caused an outbreak. This study describes an application of genomics as a useful method to discern endemic and outbreak clones when applied to strains of the same species (E. coli) with the same resistance determinant (NDM-5) and the relevance of screening patients admitted in critical units for carbapenemase producers to prevent outbreaks.

Cross-Border Emergence of Escherichia coli Producing the Carbapenemase NDM-5 in Switzerland and Germany

A series of clinical NDM-5-producing Escherichia coli isolates obtained from two surveillance networks for carbapenem-producing Enterobacterales from 2018 to 2019, namely, Switzerland (NARA) and Germany (SurvCARE), were analyzed. The 33 NDM-5-producing E. coli isolates were highly resistant to β-lactams, including novel β-lactam/β-lactamase inhibitor combinations (ceftazidime-avibactam, imipenem-relebactam, and meropenem-vaborbactam), and remained susceptible to fosfomycin, colistin, and tigecycline. These isolates were assigned to different sequence types (STs) and indicated a predominance of isolates exhibiting ST167 in Switzerland and Germany (n = 10) (phylogenetic group C), followed by ST405 (n = 4) (phylogenetic group E), ST1284 (n = 4) (phylogenetic group C), and ST361 (n = 4) (phylogenetic group C). The bla _NDM-5 gene was predominantly present on an IncF-type plasmid (n = 29) and, to a lesser extent, on the narrow-host-range IncX3 plasmid (n = 4). Sequence analyses of eight NDM-5 plasmids indicated that NDM-5-encoding F-type plasmids varied in size between 86 and 132 kb. The two IncX3 plasmids pCH8NDM5 and pD12NDM5 were 46 and 45 kb in size, respectively. The highly conserved bla _NDM-5 genetic surrounding structures (ΔISAba125-bla _NDM-5-ble _MBL-trpT-dsbD-IS26) of both the F-type and IncX3 plasmids suggested a common genetic origin. The emergence of the NDM-5 carbapenemase was evidenced in particular for the E. coli ST167 clone, which is a successful epidemic clone known to be associated with both multiresistance and virulence traits and is therefore of high public health concern. The occurrence of clonally related NDM-5-producing E. coli isolates in Switzerland and Germany further indicates the international spread of this multidrug-resistant superbug at least throughout Europe.

Surveillance of OXA-244-producing Escherichia coli and epidemiologic investigation of cases, Denmark, January 2016 to August 2019

Background

Carbapenemase-producing Escherichia coli are increasing worldwide. In recent years, an increase in OXA-244-producing E. coli isolates has been seen in the national surveillance of carbapenemase-producing organisms in Denmark.

Aim

Molecular characterisation and epidemiological investigation of OXA-244-producing E. coli isolates from January 2016 to August 2019.

Methods

For the epidemiological investigation, data from the Danish National Patient Registry and the Danish register of civil registration were used together with data from phone interviews with patients. Isolates were characterised by analysing whole genome sequences for resistance genes, MLST and core genome MLST (cgMLST).

Results

In total, 24 OXA-244-producing E. coli isolates were obtained from 23 patients. Among the 23 patients, 13 reported travelling before detection of the E. coli isolates, with seven having visited countries in Northern Africa. Fifteen isolates also carried an extended-spectrum beta-lactamase gene and one had a plasmid-encoded AmpC gene. The most common detected sequence type (ST) was ST38, followed by ST69, ST167, ST10, ST361 and ST3268. Three clonal clusters were detected by cgMLST, but none of these clusters seemed to reflect nosocomial transmission in Denmark.

Conclusion

Import of OXA-244 E. coli isolates from travelling abroad seems likely for the majority of cases. Community sources were also possible, as many of the patients had no history of hospitalisation and many of the E. coli isolates belonged to STs that are present in the community. It was not possible to point at a single country or a community source as risk factor for acquiring OXA-244-producing E. coli.

Identification of an extensively drug-resistant Escherichia coli clinical strain harboring mcr-1 and blaNDM-1 in Korea

The development of colistin resistance in carbapenem-resistant strains poses a serious public health problem. In this study, we collected 249 carbapenem-resistant Escherichia coli isolates from patients in Seoul in 2018, and screened all isolates for colistin resistance and for the presence of mobile colistin resistance (mcr) genes. Colistin-resistant strains were further analyzed using multilocus sequence typing, antimicrobial susceptibility testing, detection of antibiotic resistance determinants, plasmid transconjugation, and whole-genome sequencing. Three of the 249 carbapenem-resistant isolates were resistant to colistin, and mcr-1 was detected in one isolate (SECR18-0888), which belonged to sequence type 156 and was resistant to all antibiotics tested except tigecycline. The mcr-1.1 gene was located on an ~62 kb self-transferable IncI2 plasmid along with the bla_CTX-M-55 gene, and the bla_NDM-1, bla_TEM, qepA1, and rmtB genes were additionally detected in SECR18-0888. As an extensively drug-resistant E. coli strain producing MCR-1 and NDM-1 was identified in Korea for the first time, continued monitoring of colistin resistance in carbapenem-resistant Enterobacteriaceae should be reinforced.

Novel Insights and Features of the NDM-5-Producing Escherichia coli Sequence Type 167 High-Risk Clone

Escherichia coli sequence type 167 (ST167), producing the metallo beta-lactamase NDM-5, has been isolated as a colonizer of patients recovered at the University Hospital Policlinico Umberto I of Rome. Phylogenesis and comparative analysis of the genomes of these strains were performed against 343 ST167 genomes available from the EnteroBase database. These analyses revealed that resistance plasmids, integrative conjugative elements (ICEs), carrying the yersiniabactin virulence trait and capsular synthesis gene clusters had variable compositions and distributions within different strains of the ST167 clone. A novel capsular synthesis gene cluster, highly similar to the K48 cluster previously described only for Klebsiella pneumoniae, was identified in phylogenetically related strains of the ST167 clone.IMPORTANCE Global dissemination of some E. coli high-risk clones has been described in the last decades. The most widespread was the ST131 clone, associated with extended-spectrum-beta-lactamase (ESBL) production. Genomics of ST131 demonstrated that one clade within the ST emerged in the early 2000s, followed by a rapid, global expansion. The E. coli ST167 clone is emerging throughout the world, being frequently reported for its association with carbapenem resistance. Our study shows that virulence features are differently represented within the ST167 population. One clade shows the K48 capsular synthesis gene cluster of K. pneumoniae, not previously described for E. coli, and is populated by NDM-5-producing strains. The combination of resistance and virulence may sustain the global expansion of this specific ST167 clade.

Type VI Secretion System in Pathogenic Escherichia coli: Structure, Role in Virulence, and Acquisition

Bacterial pathogens utilize a myriad of mechanisms to invade mammalian hosts, damage tissue sites, and evade the immune system. One essential strategy of Gram-negative bacteria is the secretion of virulence factors through both inner and outer membranes to reach a potential target. Most secretion systems are harbored in mobile elements including transposons, plasmids, pathogenicity islands, and phages, and Escherichia coli is one of the more versatile bacteria adopting this genetic information by horizontal gene transfer. Additionally, E. coli is a bacterial species with members of the commensal intestinal microbiota and pathogens associated with numerous types of infections such as intestinal, urinary, and systemic in humans and other animals. T6SS cluster plasticity suggests evolutionarily divergent systems were acquired horizontally. T6SS is a secretion nanomachine that is extended through the bacterial double membrane; from this apparatus, substrates are conveyed straight from the cytoplasm of the bacterium into a target cell or to the extracellular space. This nanomachine consists of three main complexes: proteins in the inner membrane that are T4SS component-like, the baseplate complex, and the tail complex, which are formed by components evolutionarily related to contractile bacteriophage tails. Advances in the T6SS understanding include the functional and structural characterization of at least 13 subunits (so-called core components), which are thought to comprise the minimal apparatus. So far, the main role of T6SS is on bacterial competition by using it to kill neighboring non-immune bacteria for which antibacterial proteins are secreted directly into the periplasm of the bacterial target after cell-cell contact. Interestingly, a few T6SSs have been associated directly to pathogenesis, e.g., roles in biofilm formation and macrophage survival. Here, we focus on the advances on T6SS from the perspective of E. coli pathotypes with emphasis in the secretion apparatus architecture, the mechanisms of pathogenicity of effector proteins, and the events of lateral gene transfer that led to its spread.