Extended-spectrum beta-lactamase (ESBL)-producing and non-ESBL-producing Escherichia coli isolates causing bacteremia in the Netherlands (2014 - 2016) differ in clonal distribution, antimicrobial resistance gene and virulence gene content

Comparison of three doses of amikacin on alternate days with a daily dose of meropenem during the same period for the treatment of urinary tract infection with E. coli: a double-blind clinical trial

OBJECTIVES

Urinary tract infections (UTIs) are very common infections in humans, and Escherichia coli (E. coli) is the commonest pathogen leading to UTIs. The generation of beta-lactamase enzymes in this bacterium results in its resistance against many antibiotics. This study compares three doses of amikacin on alternate days with a daily dose of meropenem in the same period for the treatment of UTIs with E. coli in a double-blind clinical trial.

METHODS

The current double-blind clinical trial compares three doses of amikacin on alternate days with a daily dose of meropenem in the same period for the treatment of UTIs with E. coli. The patients were assigned to two groups: Intervention (receiving a single dose of amikacin once a day at 48-h intervals for a week, three doses) and control (receiving meropenem for 1/TDS for a week).

RESULTS

The E. coli infection frequency was 61 (21 cases of non-ESBL and 40 cases of ESBL-positive infections) and the frequency of the other infections was 52 (46%). In the patients with ESBL E. coli infection, ciprofloxacin (21; 70%) showed the highest antibiotic resistance, and nitrofurantoin (33; 91.7%) showed the highest sensitivity. The baseline variables between the control and intervention groups indicated no significant difference (p > 0.05). The frequency of signs and symptoms showed no significant difference between the amikacin and meropenem groups in the first 24 h and the first week. In the second week of follow-up, no clinical signs or symptoms were observed in the two groups.

CONCLUSION

The results of this study showed that treatment with amikacin, 1 g q48h, for one week (three doses) has the same result as meropenem, 1 g q8h, for one week (21 doses). The results are the same for the treatment of UTIs with ESBL positive and ESBL negative. Amikacin can be used once every 48 h to treat UTIs, is less expensive and can be administered on an outpatient basis.

TRIAL REGISTRATION

This study was registered in the Iranian Registry of Clinical Trials (IRCT) with ID number: IRCT20170417033483N2 on the date 2018-02-13.

New methodology to assess the excess burden of antibiotic resistance using country-specific parameters: a case study regarding E. coli urinary tract infections

OBJECTIVES

Antimicrobial resistant (AMR) infections are a major public health problem and the burden on population level is not yet clear. We developed a method to calculate the excess burden of resistance which uses country-specific parameter estimates and surveillance data to compare the mortality and morbidity due to resistant infection against a counterfactual (the expected burden if infection was antimicrobial susceptible). We illustrate this approach by estimating the excess burden for AMR (defined as having tested positive for extended-spectrum beta-lactamases) urinary tract infections (UTIs) caused by E. coli in the Netherlands in 2018, which has a relatively low prevalence of AMR E. coli, and in Italy in 2016, which has a relatively high prevalence.

DESIGN

Excess burden was estimated using the incidence-based disability-adjusted life-years (DALYs) measure. Incidence of AMR E. coli UTI in the Netherlands was derived from ISIS-AR, a national surveillance system that includes tested healthcare and community isolates, and the incidence in Italy was estimated using data reported in the literature. A systematic literature review was conducted to find country-specific parameter estimates for disability duration, risks of progression to bacteraemia and mortality.

RESULTS

The annual excess burden of AMR E. coli UTI was estimated at 3.89 and 99.27 DALY/100 0000 population and 39 and 2786 excess deaths for the Netherlands and Italy, respectively.

CONCLUSIONS

For the first time, we use country-specific and pathogen-specific parameters to estimate the excess burden of resistant infections. Given the large difference in excess burden due to resistance estimated for Italy and for the Netherlands, we emphasise the importance of using country-specific parameters describing the incidence and disease progression following AMR and susceptible infections that are pathogen specific, and unfortunately currently difficult to locate.

Influence of transition from open bay units to single room units in a neonatal intensive care unit on hospital transmission of multi-drug-resistant Enterobacterales

BACKGROUND

It was shown previously that changing the design of a hospital neonatal intensive care unit (NICU) from open bay units (OBUs) to single room units (SRUs) was not associated with a reduction in Gram-negative multi-drug-resistant organism (MDRO) colonization rates. It was therefore hypothesized that colonization mainly occurs vertically, or through parents and healthcare workers, and not through environmental factors, and that transition to SRUs would not decrease the number of clusters of MDROs with an epidemiological link. To investigate this, core-genome multi-locus sequence typing (cgMLST) was applied on MDROs cultured from infants at the study hospital.

METHODS

This retrospective cohort study included all infants carrying MDROs admitted to the NICU of a tertiary care academic hospital 2 years prior to the transition from OBUs to SRUs in May 2017, and 1.5 years after the transition (2018-2020).

RESULTS

In total, 55 infants were diagnosed with MDRO carriership. Isolates were available from 49 infants for cgMLST. In the OBU period, one cluster involving four of 20 (20%) infants was identified, and in the SRU period, four clusters involving nine of 29 (31%) infants were identified. It was possible to make an epidemiological link in all four SRU MDRO clusters, but this was not possible for the OBU cluster. In the latter case, transmission from an environmental source on the ward seemed likely.

CONCLUSION

After transition to SRUs, there was no decrease in the number of clusters of MDROs with an epidemiological link, suggesting that nursing infants in an NICU with an SRU design is not, in itself, protective against the acquisition of MDROs.

Identification and Evaluation of Pathogenic Genes (traT, hly, aer, pap, and fimH) and Antibiotic Resistance Genes (blaTEM, blaSHV, and blaCTX) in Escherichia coli in Patients Referred to Gonabad Hospitals, Iran

Background

Urinary tract infection (UTI) is one of the common bacterial infections. Escherichia coli is the most common cause of UTI. In this research, the prevalence of several virulence factors and beta-lactam resistance genes was investigated.

Methods

One hundred E. coli isolates were collected from patients' specimens with UTI referred to Allame-Bohlol Gonabadi hospital. Polymerase chain reaction (PCR) was performed to identify five pathogenic genes (fimH, aer, pap, hly, traT) and three antibiotic resistance genes (blaTEM, blaCTX, blaSHV).

Results

The frequencies of blaSHV, blaTEM and blaCTX beta-lactamase genes among extended-spectrum-beta-lactamases (ESBLs) positive isolates were 11.1%, 48.1%, and 93.3%, respectively. A significant number of isolates were resistant to the most commonly used antibiotics.

Conclusion

Pathogenic genes may also increase the severity, progression, and expansion of urinary tract infections. Therefore, identifying these genes as critical controllers of illness can use for better manage the treatment.

Antibiotic resistance spectrum of E. coli strains from different samples and age-grouped patients: a 10-year retrospective study

OBJECTIVE

Escherichia coli (E. coli) is the most common opportunistic clinical micro-organism with high drug resistance. This study aimed to analyse the resistance pattern of E. coli according to patient age and clinical sample type.

DESIGN AND SETTING

This retrospective observational study was conducted in a tertiary hospital in southeastern China.

PARTICIPANTS

E. coli strains were isolated from blood, urine and sputum of infected inpatients. The patients were divided into four age groups: children (0-14 years old, including neonatal and non-neonatal groups), youths (15-40 years old), middle-aged (41-60 years old) and old (>60 years old).

RESULTS

A total of 7165 E. coli strains were collected from all samples. Compared with urine and blood isolates, more sputum isolates were resistant against 12 tested antibiotics. Furthermore, urine isolates were more resistant to levofloxacin than sputum and blood isolates. Although the patients' age was not associated with resistance rates of E. coli strains isolated from blood, a larger proportion of urine-derived strains from youths were resistant to sulfamethoxazole-trimethoprim and piperacillin-tazobactam than those from old people. The sputum strains from the elderly were more resistant to most of the tested antibiotics compared with sputum strains isolated from children.

CONCLUSIONS

The resistance profile of E. coli is different among age groups and specimen sources and should be considered during E. coli infection treatment.

The Prevalence of Multidrug-Resistant Escherichia coli Producing ESBL among Male and Female Patients with Urinary Tract Infections in Riyadh Region, Saudi Arabia

The Escherichia coli that produces extended-spectrum lactamases (ESBL-E. coli) can develop resistance to many antibiotics. The control of ESBL-E. coli disorders is challenging due to their restricted therapeutic approaches, so this study aims to determine the prevalence and pattern of the antibiotic resistance of ESBL-E. coli among male and female patients with urinary tract infections in Riyadh, Saudi Arabia. During the period of 2019 to 2020 at King Fahd Medical City, Riyadh, 2250 urine samples from patients with urinary tract infections (UTIs) were collected, and microbial species were cultured and identified using standard biochemical techniques. A double-disc synergy test was used to identify ESBL-producing strains of E. coli, and an in vitro method and the clinical laboratory standard institute (CLSI) criteria were employed to determine the resistance of these strains to antimicrobial drugs. ESBL-E. coli was detected in 510 (33.49%) of the 1523 E. coli isolates, 67.27% of which were recovered from women and 33.7% of which were recovered from men. A total of 284 (55.69%) ESBL-E. coli isolates were found in patients under 50 years of age, and 226 (44.31%) were found in patients over 50 years of age. Nearly all the isolates of ESBL-E. coli were resistant to cephalosporins (ceftriaxone, cefotaxime, cefepime, cefuroxime, and cephalothin) and penicillin (ampicillin), whereas the majority of the isolates were sensitive to several carbapenems (imipenem, meropenem, and ertapenem), aminoglycosides (amikacin), and nitrofurantoins. The development of antibiotic resistance by ESBL-E. coli, the most frequent pathogen linked to urinary tract infections, plays a crucial role in determining which antibiotic therapy is appropriate.

Convergence of virulence and antimicrobial resistance in increasingly prevalent Escherichia coli ST131 papGII+ sublineages

Escherichia coli lineage ST131 is an important cause of urinary tract and bloodstream infections worldwide and is highly resistant to antimicrobials. Specific ST131 lineages carrying invasiveness-associated papGII pathogenicity islands (PAIs) were previously described, but it is unknown how invasiveness relates to the acquisition of antimicrobial resistance (AMR). In this study, we analysed 1638 ST131 genomes and found that papGII+ isolates carry significantly more AMR genes than papGII-negative isolates, suggesting a convergence of virulence and AMR. The prevalence of papGII+ isolates among human clinical ST131 isolates increased dramatically since 2005, accounting for half of the recent E. coli bloodstream isolates. Emerging papGII+ lineages within clade C2 were characterized by a chromosomally integrated blaCTX-M-15 and the loss and replacement of F2:A1:B- plasmids. Convergence of virulence and AMR is worrying, and further dissemination of papGII+ ST131 lineages may lead to a rise in severe and difficult-to-treat extraintestinal infections.

Genomic analyses indicate that the ST131 lineage of E. coli, responsible for urinary and bloodstream infections globally, is evolving towards both increased virulence and increased resistance to antimicrobials.

External validation of WGS-based antimicrobial susceptibility prediction tools, KOVER-AMR and ResFinder 4.1 for Escherichia coli clinical isolates

OBJECTIVE

To externally validate whole genome sequence-antimicrobial susceptibility testing (WGS-AST) phenotype prediction tools KOVER-AMR and ResFinder 4.1 for Escherichia coli clinical isolates from Dutch routine care.

METHODS

A random sample of 234 E. coli, and 283 3^rd generation cephalosporin-resistant E. coli isolates from urine and blood were collected (2014-17). Culture-AST was performed using VITEK 2 and BD Phoenix. Sequences were used as input for KOVER-AMR-SCM, KOVER-AMR-CART and ResFinder 4.1. The concordance, major error rate (MER), and very major error rate (VMER) were calculated, with subsequent comparison to U.S. Food and Drug Administration (FDA) criteria (MER ≤3%, and VMER with a 95% confidence interval (CI) ≤1.5%-≤7.5%).

RESULTS

ResFinder 4.1 performed better than KOVER-AMR-models, however, neither tools achieved overall (V)MERs below FDA criteria. KOVER-AMR-SCM, KOVER-AMR-CART, and ResFinder 4.1, MER (cumulative all antimicrobials) were: 5.1% (4.4-5.9), 4.3% (3.6-5.0), and 5.1% (4.5-5.8), respectively. MERs ≤3% were achieved for 6 (SCM) and 5 (CART) of the 11 tested antimicrobials for KOVER-AMR-models, and for 9/13 antimicrobials tested with ResFinder 4.1. KOVER-AMR-SCM, KOVER-AMR-CART, and ResFinder 4.1, cumulative VMERs were: 26% (24-28), 29% (27-31), and 11% (9.2-12). VMERs with a 95%CI ≤1.5-≤7.5 were only achieved for 4/13 tested antimicrobials with ResFinder 4.1.

CONCLUSION

In this study, WGS-AST phenotype prediction tools, KOVER-AMR and ResFinder 4.1, did not meet the FDA criteria needed for clinical diagnostic use in 517 E. coli clinical isolates from Dutch routine care. The tested tools should be further improved before they can be used for clinical decision making.

GLO1 Contributes to the Drug Resistance of Escherichia coli Through Inducing PER Type of Extended-Spectrum β-Lactamases

Background

Escherichia coli-associated antimicrobial resistance (AMR) issue so far needs urgent considerations. This study aims to screen the potent genes associated with extended-spectrum β-lactamases (ESBLs) in drug-resistant Escherichia coli and elucidate the specific drug-resistant mechanism.

Methods

Clinical ESBLs-EC samples were obtained based on the microbial identification, and the whole genome was sequenced. In combination with the significantly enriched pathways, several differently expressed genes were screened and verified by RT-PCR. Furthermore, through knocking out glyoxalase 1 (GLO1) gene and transfecting overexpressed plasmids, the potential relationship between GLO1 and ESBLs was then investigated. Lastly, the concentrations of β-lactamases in bacteria and supernatant from different groups were examined by enzyme-linked immunosorbent assay (ELISA).

Results

After successful isolation and identification of ESBLs-EC, the whole genome and eighteen differential metabolic pathways were analyzed to select differently expressed genes, including add, deoD, guaD, speG, GLO1, VNN1, etc. RT-PCR results showed that there were no differences in these genes between the standard bacteria and susceptible Escherichia coli. Remarkably, the relative levels of four genes including speG, Hdac10, GLO1 and Ppcdc were significantly increased in ESBLs-EC in comparison with susceptible strains, whereas other gene expression was decreased. Further experiments utilizing gene knockout and overexpression strains confirmed the role of GLO1. At last, a total of 10 subtypes of β-lactamases were studied using ELISA, including BES-, CTX-M1-, CTX-M2-, OXA1-, OXA2-, OXA10-, PER-, SHV-, TEM-, and VEB-ESBLs, and results demonstrated that GLO1 gene expression only affected PER-β-lactamases but had no effects on other β-lactamases.

Conclusion

SpeG, Hdac10, GLO1 and Ppcdc might be associated with the drug-resistant mechanism of Escherichia coli. Of note, this study firstly addressed the role of GLO1 in the drug resistance of ESBLs-EC, and this effect may be mediated by increasing PER-β-lactamases.

Drug susceptibility and molecular epidemiology of Escherichia coli in bloodstream infections in Shanxi, China

Objectives

We carried out a retrospective study to investigate the drug susceptibility and genetic relationship of clinical Escherichia coli isolates from patients with BSIs in Shanxi, China.

Methods

E. coli isolates causing BSIs were consecutively collected from June 2019 to March 2020. Antimicrobial susceptibility testing was performed by broth microdilution method. PCR was used to detect antimicrobial resistance genes coding for extended-spectrum β-lactamases (ESBLs), phylogenetic groups and seven housekeeping genes of E. coli.

Results

A total of 76 E. coli were collected. Antimicrobial susceptibility testing revealed that the top six E. coli resistant antibiotics were ampicillin (90.7%), ciprofloxacin (69.7%), cefazolin (65.7%), levofloxacin (63.1%), ceftriaxone and cefotaxime (56.5%). Among the 76 isolates, 43 produced ESBLs. Molecular analysis showed that CTX-M-14 was the most common ESBLs, followed by CTX-M-15 and CTX-M-55. Phylogenetic group D (42.2%) predominated, followed by group B2 (34.2%), group A (18.4%) and group B1 (5.2%). The most prevalent sequence types (STs) were ST131 (15/76), ST69 (12/76) and ST38 (6/76).

Conclusions

This study is the first to report the phenotypic and molecular characteristics of E. coli isolated from BSIs in Shanxi, China. Our results indicated a high prevalence of MDR in E. coli strains isolated from BSIs and a serious spread of ESBL genes in Shanxi, especially the epidemiological bla _CTX-M. Phylogenetic analysis indicated genetic diversity among E. coli BSIs isolates.

Antibiotic Resistance Pattern of Extended Spectrum Beta Lactamase Producing Escherichia coli Isolated From Patients With Urinary Tract Infection in Morocco

Extended-spectrum β-lactamases producing Escherichia coli (ESBL-EC) lend resistance to most β-lactam antibiotics. Because of limited treatment options, ESBL-EC infections are generally more difficult to treat, leading to higher hospital costs, reduced rates of microbiological and clinical responses, and a threat to the patient’s life. This study aimed to determine the antibiotic resistance pattern of ESBL-EC isolated from patients with urinary tract infection in Morocco. This retrospective laboratory-based study was conducted at Cheikh Khalifa International University Hospital, Casablanca, from January 2016 to June 2019. A total of 670 urine samples were collected from urinary tract infection patients and processed by standard microbiological methods. In vitro susceptibility testing to different antibiotics of all identified isolates of Escherichia coli (E. coli) was performed following Kirby–Bauer’s disc diffusion method on Mueller–Hinton Agar according to the EUCAST standards. The reviewing of ESBL-EC was confirmed by the appearance of a characteristically shaped zone referred to as a “champagne cork” using the Combined Disk Test. Among a total of 438 E. coli isolated from nonrepetitive urine samples, two hundred fifty-nine (59%) were ESBL-EC, of which 200 (77%) were isolated from adult patients (over the age of 50) and the majority were female. All ESBL-EC isolates were resistant to third-generation cephalosporin and quinolones and sensitive to carbapenem and fosfomycin. Knowledge of antimicrobial resistance patterns in ESBL-EC, the major pathogen associated with urinary tract infection, is indispensable as a guide in choosing empirical antimicrobial treatment.

Ten-year longitudinal molecular epidemiology study of Escherichia coli and Klebsiella species bloodstream infections in Oxfordshire, UK

Background

The incidence of Gram-negative bloodstream infections (BSIs), predominantly caused by Escherichia coli and Klebsiella species, continues to increase; however, the causes of this are unclear and effective interventions are therefore hard to design.

Methods

In this study, we sequenced 3468 unselected isolates over a decade in Oxfordshire (UK) and linked this data to routinely collected electronic healthcare records and mandatory surveillance reports. We annotated genomes for clinically relevant genes, contrasting the distribution of these within and between species, and compared incidence trends over time using stacked negative binomial regression.

Results

We demonstrate that the observed increases in E. coli incidence were not driven by the success of one or more sequence types (STs); instead, four STs continue to dominate a stable population structure, with no evidence of adaptation to hospital/community settings. Conversely in Klebsiella spp., most infections are caused by sporadic STs with the exception of a local drug-resistant outbreak strain (ST490). Virulence elements are highly structured by ST in E. coli but not Klebsiella spp. where they occur in a diverse spectrum of STs and equally across healthcare and community settings. Most clinically hypervirulent (i.e. community-onset) Klebsiella BSIs have no known acquired virulence loci. Finally, we demonstrate a diverse but largely genus-restricted mobilome with close associations between antimicrobial resistance (AMR) genes and insertion sequences but not typically specific plasmid replicon types, consistent with the dissemination of AMR genes being highly contingent on smaller mobile genetic elements (MGEs).

Conclusions

Our large genomic study highlights distinct differences in the molecular epidemiology of E. coli and Klebsiella BSIs and suggests that no single specific pathogen genetic factors (e.g. AMR/virulence genes/sequence type) are likely contributing to the increasing incidence of BSI overall, that association with AMR genes in E. coli is a contributor to the increasing number of E. coli BSIs, and that more attention should be given to AMR gene associations with non-plasmid MGEs to try and understand horizontal gene transfer networks.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-021-00947-2.

Predominance of CTX-M-15-producing ST131 strains among ESBL-producing Escherichia coli isolated from asylum seekers in the Netherlands

Objectives

Numerous studies show increased prevalence of MDR bacteria amongst asylum seekers, but data on the molecular profiles of such strains are limited. We aimed to evaluate the molecular profiles of ESBL-producing Escherichia coli (ESBL-E. coli) strains isolated from asylum seekers and investigate their phylogenetic relatedness.

Methods

WGS data of ESBL-E. coli isolates from asylum seekers, retrieved from 1 January to 31 December 2016, were analysed to assess MLST STs, fim types, phylogroups and resistance genes. Fifty-two ESBL-E. coli isolates from the Dutch–German border region were used for genome comparison purposes as a control group.

Results

Among 112 ESBL-E. coli isolates from asylum seekers, originating mostly from Syria (n = 40) and Iraq (n = 15), the majority belonged to ST131 (21.4%) and ST10 (17.0%). The predominant gene for β-lactam resistance was bla_CTX-M-15 (67.9%), followed by the often co-detected bla_TEM-1B (39.3%). No mcr or carbapenemase genes were detected. The majority of the strains belonged to phylogroups B2 (38.4%) and A (32.1%), carrying fimH27 (25%) and fimH30 (19.6%). A core genome MLST minimum spanning tree did not reveal clusters containing strains from the asylum seekers and the control group. Five clusters were formed within the asylum seeker group, by strains isolated from people originating from different countries.

Conclusions

The most frequently isolated clones in this study were isolated on a regular basis within the Dutch population before the increase in the asylum seeker population. No mcr- or carbapenemase-producing clones were detected among the asylum seeker population. Minor clustering was observed amongst the asylum seeker strains.

Multidrug-Resistant Extended-Spectrum β-Lactamase-Producing Escherichia coli Isolated from Vegetable Farm Soil in South Korea

The populations of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) have increasingly disseminated in humans, animals, and the environment. This study aimed to determine the prevalence, antimicrobial susceptibilities, and molecular characteristics of ESBL-EC isolates obtained from vegetable farm soil. In total, 200 soil samples were collected from vegetable farms in Incheon, South Korea, between 2018 and 2019 and cultured on MacConkey screening plates supplemented with 2 μg/mL cefotaxime. Cefotaxime-resistant ESBL-EC isolates were recovered from 4.0% (8/200) of the soil samples. All eight isolates were nonsusceptible to ampicillin, piperacillin, cefazolin, cefotaxime, and cefepime and harbored bla_CTX-M-type ESBL genes, including bla_CTX-M-15 (50.0%), bla_CTX-M-55 (25.0%), and bla_CTX-M-14 (25.0%). Phylogenetic analysis showed that the B1 lineage was predominant (75.0%), followed by A (12.5%) and B2 (12.5%) lineages. Multilocus sequence typing revealed eight different E. coli sequence types (STs), including ST10, ST73, ST155, ST847, ST2521, ST3285, ST5173, and ST9479. Notably, ST10 and ST73 belong to the global extraintestinal pathogenic E. coli lineages. Our findings demonstrated that the farm soil environment may serve as a reservoir of human-associated multidrug-resistant ESBL-producing pathogens.

Ten years of population-level genomic Escherichia coli and Klebsiella pneumoniae serotype surveillance informs vaccine development for invasive infections

BACKGROUND

The incidence of bloodstream infections (BSIs) caused by Escherichia coli and Klebsiella pneumoniae is increasing, with substantial associated morbidity, mortality and antimicrobial resistance. Unbiased serotyping studies to guide vaccine target selection are limited.

METHODS

We conducted unselected, population-level genomic surveillance of bloodstream E. coli and Klebsiella pneumoniae isolates from 2008-2018 in Oxfordshire, UK. We supplemented this with an analysis of publicly available global sequencing data (n=3678).

RESULTS

We sequenced 3478 E. coli isolates (3278 passed quality control) and 556 K. pneumoniae isolates (535 (K-antigen) and 549 (O-antigen) passed quality control). The four most common E. coli O-antigens (O1/O2/O6/O25) were identified in 1499/3278 isolates; the incidence of these O-types increased over time (IRRy=1.14, 95% CI:1.11-1.16). These O-types accounted for 616/1434 multidrug resistant (MDR) and 173/256 extended-spectrum beta-lactamase(ESBL)-resistant isolates in Oxfordshire, but only 19/90 carbapenem-resistant isolates across all studies. For Klebsiella pneumoniae, the most common O-antigens (O2v2/O1v1/O3b/O1v2) accounted for 410/549 isolates; the incidence of BSIs caused by these also increased annually (IRRy=1.09; 95% CI:1.05-1.12). These O-types accounted for 122/148 MDR and 106/123 ESBL isolates in Oxfordshire and 557/734 carbapenem-resistant isolates across all studies. Conversely we observed substantial capsular antigen diversity. Analysis of 3678 isolates from global studies demonstrated the generalisability of these findings. For E. coli, based on serotyping, the ExPEC4V and ExPEC10V vaccines under investigation would cover 46% and 72% of Oxfordshire isolates respectively, and 47% and 71% of MDR isolates.

CONCLUSIONS

O-antigen targeted vaccines may be useful in reducing the morbidity, mortality and antimicrobial resistance associated with E. coli and K. pneumoniae BSIs.

Horizontally acquired papGII-containing pathogenicity islands underlie the emergence of invasive uropathogenic Escherichia coli lineages

Escherichia coli is the leading cause of urinary tract infection, one of the most common bacterial infections in humans. Despite this, a genomic perspective is lacking regarding the phylogenetic distribution of isolates associated with different clinical syndromes. Here, we present a large-scale phylogenomic analysis of a spatiotemporally and clinically diverse set of 907 E. coli isolates, including 722 uropathogenic E. coli (UPEC) isolates. A genome-wide association approach identifies the (P-fimbriae-encoding) papGII locus as the key feature distinguishing invasive UPEC, defined as isolates associated with severe UTI, i.e., kidney infection (pyelonephritis) or urinary-source bacteremia, from non-invasive UPEC, defined as isolates associated with asymptomatic bacteriuria or bladder infection (cystitis). Within the E. coli population, distinct invasive UPEC lineages emerged through repeated horizontal acquisition of diverse papGII-containing pathogenicity islands. Our findings elucidate the molecular determinants of severe UTI and have implications for the early detection of this pathogen.

Isolation and complete genome sequencing of the virulent phage vB_EcoS_XY3 infecting multidrug-resistant Escherichia coli

A virulent phage, named vB_EcoS_XY3, was isolated from hospital wastewater in Xiangyang, China. Its morphological characteristics, growth parameters, adsorption rate, and pH and temperature stability were determined. Phage vB_EcoS_XY3 was found to be able to infect Escherichia coli laboratory strains and also some multidrug-resistant E. coli strains. Its complete genome consists of 51,345 base pairs of double-stranded DNA with an average GC content of 55.24% and 85 putative protein-coding genes. Forty-four genes were annotated with known functions. These results will not only provide further insights into E. coli phages but also have implications for the development of potential biocontrol agents.

Identification and characterization of two bacteriophages with lytic activity against multidrug-resistant Escherichia coli

Escherichia coli is an opportunistic bacterial pathogen that causes a wide range of nosocomial infections. The emergence of multidrug resistance in E. coli poses a severe threat to global health. Phage therapies are an alternative method to control multidrug-resistant pathogens, which have been attracting increasing attention. Owing to their ability to lyse bacteria specifically and efficiently, bacteriophages are considered novel antimicrobial agents. In this study, we used multidrug-resistant E. coli as an indicator and isolated, characterized, and compared two new phages of the Siphoviridae family referred to as vB_EcoS_XF and vB_EcoS_XY2. These phages were able to infect several pathogenic multidrug-resistant E. coli strains. A short latent period and large burst size ensured their rapidly reproduction in host cells. Their tolerance of high temperatures and high pH levels meant that remained stable when used to control pathogenic E. coli strains. No obvious cytotoxicity was observed when either HEK293 T or A549 cells were incubated with these two phages. Mass spectrometry analysis allowed us to identify several phage-encoded proteins. Genomic analysis revealed that no toxic proteins or antibiotic proteins were encoded. Genome comparison and phylogenetic analysis indicated that the phages identified show high similarity with E. coli phages of the genus Kagunavirus. The desirable characteristics of the novel phages identified make them good potential therapeutic candidates, and components of phage cocktails to treat multidrug-resistant E. coli in the future.

Validation of a Worst-Case Scenario Method Adapted to the Healthcare Environment for Testing the Antibacterial Effect of Brass Surfaces and Implementation on Hospital Antibiotic-Resistant Strains

The evaluation of antibacterial activity of metal surfaces can be carried out using various published guidelines which do not always agree with each other on technical conditions and result interpretation. Moreover, these technical conditions are sometimes remote from real-life ones, especially those found in health-care facilities, and do not include a variety of antibiotic-resistant strains. A worst-case scenario protocol adapted from published guidelines was validated on two reference strains (Staphylococcus aureus ATCC 6538 and Enterobacter aerogenes ATCC 13048). This protocol was designed to be as close as possible to a healthcare facility environment, including a much shorter exposure-time than the one recommended in guidelines, and evaluated the impact of parameters such as the method used to prepare inocula, seed on the surface, and recover bacteria following exposure. It was applied to a panel of 12 antibiotic-resistant strains (methicillin resistant, vancomycin-resistant, beta-lactamase, and carbapenemase producing strains as well as efflux pump-overexpressing ones) chosen as representative of the main bacteria causing hospital acquired infections. Within a 5-min exposure time, the tested brass surface displayed an antibacterial effect meeting a reduction cut-off of 99% compared to stainless steel, whatever the resistance mechanism harbored by the bacteria.

Pathogenic Escherichia coli in Dogs Reveals the Predominance of ST372 and the Human-Associated ST73 Extra-Intestinal Lineages

Escherichia coli is a ubiquitous commensal and pathogen that has also been recognized as a multi-sectoral indicator of antimicrobial resistance (AMR). Given that latter focus, such as on resistances to extended-spectrum cephalosporins (ESC) and carbapenems, the reported population structure of E. coli is generally biased toward resistant isolates, with sequence type (ST)131 being widely reported in humans, and ST410 and ST648 being reported in animals. In this study, we characterized 618 non-duplicate E. coli isolates collected throughout France independently of their resistance phenotype. The B2 phylogroup was over-represented (79.6%) and positively associated with the presence of numerous virulence factors (VFs), including those defining the extra-intestinal pathogenic E. coli isolates (presence of ≥2 VFs: papA, sfaS, focG, afaD, iutA, and kpsMTII) and those more specifically related to uropathogenic E. coli (cnf1, hlyD). The major STs associated with clinical isolates from dogs were by far the dog-associated ST372 (20.7%) and ST73 (20.1%), a lineage that had commonly been considered until now as human-associated. Resistance to ESC was found in 33 isolates (5.3%), along with one carbapenemase-producing isolate, and was mostly restricted to non-B2 isolates. In conclusion, the presence of virulent E. coli lineages may be the issue, rather than the presence of ESC-resistant isolates, and the risk of transmission of such virulent isolates to humans needs to be further studied.