Escherichia coli ST1193: Following in the Footsteps of E. coli ST131

Emergent Escherichia coli of the highly virulent B2-ST1193 clone producing KPC-2 carbapenemase in ready-to-eat vegetable

OBJECTIVES

Critical priority carbapenem-resistant pathogens constitute a worldwide public health problem. Escherichia coli ST1193 is an emerging high-risk clone that demonstrates prolonged gut persistence, and association with community-onset urinary and bloodstream infections. The purpose of this study is to report microbiological and genomic data on the emergence of KPC-2-producing E. coli ST1193 in ready-to-eat (RTE) vegetable.

METHODS

RTE vegetables were purchased from markets in southeastern Brazil. Epiphytic and endophytic Gram-negative bacteria displaying resistance to broad-spectrum beta-lactams were identified by MALDI-TOF. WGS was conducted using the Illumina NextSeq platform. Antimicrobial susceptibility, conjugation, and acid tolerance assays were performed. Virulence behavior was evaluated using the Galleria mellonella infection model.

RESULTS

Epiphytic KPC-2-producing E. coli belonging to pandemic ST1193 was identified in RTE arugula. Genomic analysis predicted clinically relevant genes conferring resistance to β-lactams, fluoroquinolones, hazardous heavy metals, pesticides, disinfectants, and chlorine sanitizer. The blaKPC-2 gene was carried by a conjugative IncF plasmid. Resistance of E. coli KPC-2/ST1193 at pH 2.0 was confirmed, being associated with gadWX and ibaG pH tolerance genes, supporting survival to stomach acid prior to reaching small intestine, and potential for a dietary mode of host colonization. Virulent behavior was supported by wide virulome of the highly virulent phylogroup B2, whereas cgSNP-based phylogenomics revealed clonal relationship with healthcare-associated lineages circulating in the United States, China, Mexico, France and Brazil.

CONCLUSIONS

We report the occurrence of KPC-2-producing E. coli of the highly virulent B2-ST1193 clone in RTE vegetable, highlighting a possible route of dissemination of WHO priority pathogens to humans.

Genomic Epidemiology of Pseudomonas aeruginosa Sequence Type 111

PURPOSE

Pseudomonas aeruginosa ST111 is a global multidrug resistant (MDR) high-risk clone and comprehensive data about its molecular epidemiology is limited in Canada. Comprehensive data about the evolution of ST111 clades is limited. We characterized a Canadian collection of ST111 causing bloodstream infections and investigated the genomic relationship between Canadian and global ST111.

MATERIAL AND METHODS

We used long and short read WGS to characterize Canadian ST111 (n = 10 from 2010-18). We performed phylogenetic analysis on a global collection of ST111 (n = 969) and investigated the evolutionary history of clades using BEAST.

RESULTS

ST111 belonged to 3 clades (A, B, C) and two subclades (C1, C2). ST111-A was the ancestral clade while clades B, C1 and C2 emerged during the 1700s and 1800s. ST111-C2 dominated the global ST111 population. Serotype switching from O4 to O12 and the acquisition of Tn21, gyrA_T83I, parC_S87L, In59 with blaVIM-2 and aacA29 over time, were important in the evolution of ST111-C2. The Calgary ST111 strains consisted of a diverse collection that belonged to ST111-A (O4), ST111-C1 (O4) and ST111-C2 (O12) with different transposon structures.

CONCLUSIONS

We provided details on the emergence and evolution of different ST111 clades over time and highlighted the roles of serotype switching and the acquisition of certain AMR determinants and transposon structures in the evolution of ST111-C2.

Characterization of bla NDM in two Escherichia coli ST1193 clinical isolates in the Gulf region

Introduction

Escherichia coli ST1193 is an emerging high-risk clone associated with the production of plasmid-mediated CTX-type extended-spectrum β-lactamases. However, this clone has seldom been found to contain plasmids carrying carbapenemase genes. We report two epidemiologically unlinked multidrug-resistant (MDR) clinical isolates of E. coli ST1193 with plasmids harbouring NDM-type carbapenemase genes from the Gulf region.

Methods

The isolates were identified by MALDI-TOF MS and antibiotic susceptibility testing was performed using the VITEK 2/Phoenix system. A conjugation experiment was performed to assess the transferability of the resistance plasmids. Genomic DNA of both isolates was subject to Illumina sequencing; one isolate was also sequenced using Oxford Nanopore technology. Bioinformatics analyses were performed to detect antimicrobial resistance genes, and to annotate the genetic context of the NDM genes.

Results and Conclusions

Both isolates were resistant to carbapenems using phenotypic tests. Conjugation experiment confirmed that NDM-5-encoding plasmids of both strains could be transferred to the recipient cells. The completed NDM-5-encoding plasmid of E. coli isolate FQ71 was highly similar to several plasmids from ST410 isolates in the NCBI database. Genomic analysis revealed the presence of transposase genes and transposons in the flanking regions of the NDM genes in the plasmids. Since carbapenems constitute first-line agents for the treatment of serious infections caused by ESBL producers, E. coli ST1193 isolates co-producing ESBL and NDM-type carbapenemases represent a serious challenge for antimicrobial stewardship and infection control programmes.

Emergence of Carbapenem-Resistant Uropathogenic Escherichia coli (ST405 and ST167) Strains Carrying blaCTX-M-15, blaNDM-5 and Diverse Virulence Factors in Hospitalized Patients

BACKGROUND

Urinary tract infections (UTIs) are common infectious diseases in hospital settings, and they are frequently caused by uropathogenic Escherichia coli (UPEC). The emergence of carbapenem-resistant (Carb-R) E. coli strains poses a significant threat due to their multidrug resistance and virulence. This study aims to characterize the antimicrobial resistance and virulence profiles of Carb-R UPEC strains isolated from hospitalized patients.

METHODS

A total of 1100 urine samples were collected from patients in Lahore and Faisalabad, Pakistan, between May 2023 and April 2024. The samples were processed to isolate and identify E. coli using standard microbiological techniques and VITEK®2, followed by amplification of the uidA gene. Antimicrobial susceptibility was evaluated using the Kirby-Bauer disc diffusion method and broth microdilution. Resistance and virulence genes were detected through PCR and DNA sequencing, and sequence typing was performed using MLST.

RESULTS

Among the 118 Carb-R UPEC isolates, resistance was most frequently observed against sulfamethoxazole-trimethoprim (96.6%) and doxycycline (96.6%). All of the isolates remained sensitive to colistin and tigecycline. Sequence types ST405 (35.6%) and ST167 (21.2%) were predominant and carried the blaCTX-M-15 and blaNDM-5 genes. The distribution of virulence genes and a variety of antimicrobial resistance genes (ARGs), conferring resistance to aminoglycosides, fluoroquinolones, tetracyclines, and sulfonamides, were observed as specifically linked to certain sequence types.

CONCLUSIONS

This study provides insights into the molecular epidemiology of carbapenem-resistant Uropathogenic E. coli (Carb-R UPEC) strains and highlights the presence of globally high-risk E. coli clones exhibiting extensive drug resistance phenotypes in Pakistani hospitals. The findings underscore the urgent need for enhanced surveillance and stringent antibiotic stewardship to manage the spread of these highly resistant and virulent strains within hospital settings.

Urogenital colonization and pathogenicity of E. Coli in the vaginal microbiota during pregnancy

This study explores the role of the vaginal microbiota (VM) in the pathophysiology of asymptomatic bacteriuria (ASB) in a cohort of 1,553 pregnant women. Worldwide, E. coli remains the most common etiological agent of bacteriuria during pregnancy and also a major causative agent of newborn infections. A healthy VM is typically characterized by low diversity and is dominated by lactic acid-producing species, notably those from the Lactobacillus genus. Our results point to decreases in Lactobacillus spp associated with an increase of gut-microbiota-associated species from the Enterobacterales order. Escherichia coli exhibited the most pronounced increase in abundance within the VM during bacteriuria and was notably associated with ASB. Molecular typing and antimicrobial resistance characterization of 72 metagenome assembled E. coli genomes (MAGs) from these pregnant women revealed a genomic signature of extraintestinal pathogenic E. coli ("ExPEC") strains, which are involved in various extraintestinal infections such as urinary tract infections, newborn infections and bacteremia. Microbial diversity within the vaginal samples from which an E. coli MAG was obtained showed a substantial variation, primarily marked by a decrease in abundance of Lactobacillus species. Overall, our study shows how disruption in key bacterial group within the VM can disrupt its stability, potentially leading to the colonization by opportunistic pathogens.

Extended-spectrum beta-lactamase- and carbapenemase-producing Escherichia coli isolates causing hospital- and community-acquired infections in Tunisia (2001-2019): expansion of CTX-M-15-C2 and CTX-M-27-C1 ST131 subclades

The prevalence of infections caused by extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) and carbapenemase-producing E. coli (CP-EC) is increasing worldwide. We investigated the epidemiology of ESBL-EC and CP-EC causing hospital-acquired (HA) infections in a large teaching hospital in Tunisia over the last two decades and compared it with a collection of 107 community-acquired (CA) ESBL-EC isolates. Between 2001 and 2019, the incidence of HA ESBL-EC increased significantly from 0.08 to 0.32 cases per 1,000 patient days, due entirely to the rapid emergence and expansion of ST131, which accounted for 42.3% (157/371) of HA ESBL-EC. Most ESBL-EC harbored the CTX-M type (92%) with a predominance of blaCTX-M-15. The C2/H30-Rx subclone (n = 103, 65.6%) accounted for 90% of ST131 isolates between 2003 and 2012 and was exclusively associated with CTX-M-15, whereas cluster C1-M27, which was associated with CTX-M-27, emerged in 2013 and expanded gradually to 55% of ST131 in 2019. ST131 prevalence was higher among CA ESBL-EC than HA ESBL-EC (63.6% vs. 42.3%, P = 0.002). CA C2 subclone and non-ST131 isolates showed higher virulence scores than HA isolates. The incidence of CP-EC remained stable over the study period with a mean of 0.08 cases per 1,000 patient days. Among the 38 identified CP-EC isolates, only 16.2% belonged to the ST131 clone and 81.5% produced OXA-48-like carbapenemases. ST131 is the major driver of ESBL-EC spread in both hospital and community settings in Tunisia, mainly linked to the expansion of the CTX-M-15-C2 and CTX-M-27-C1 subclades. The emergence of CP-EC requires ongoing genomic surveillance.

IMPORTANCE

We aimed to investigate the microbiological features of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) and carbapenemase-producing E. coli (CP-EC) causing hospital- and community-acquired infections in Tunisia over the last two decades. The study captured the emergence and expansion of the CTX-M-15-C2 ST131 subclade and successively the CTX-M-27-C1 ST131 subclade, which were responsible for the steady increase in the prevalence of ESBL-EC. However, the incidence of CP-EC remained stable over the study period with a highly diverse content in carbapenemase genes dominated by blaOXA-48-like. This is the first study to provide comprehensive data on the epidemiology of ESBL-EC and CP-EC in a North African country.

Clonal and resistance profiles of fluoroquinolone-resistant uropathogenic Escherichia coli in countries with different practices of antibiotic prescription

Background

Antibiotic prescription practices differ between countries, influencing regional antimicrobial resistance prevalence. However, comparisons of clonal diversity among resistant bacteria in countries with different prescribing practices are rare. The rise of fluoroquinolone-resistant Escherichia coli (FQREC), often multidrug-resistant, exacerbates global antibiotic resistance. Unlike in the USA, antibiotics are commonly dispensed in Iraq without prescriptions, leading to widespread overuse and misuse. This study aimed to assess the impact of varying antibiotic use practices on FQREC diversity.

Methods

We compared FQREC prevalence, multidrug resistance, and clonality of FQREC among E. coli isolated from urine submitted between 2017 and 2018 to three US hospitals and two Iraqi hospitals. All FQREC isolates were analyzed for QRDR mutations and the presence of PMQR genes. A subset of FQREC strains from the ST131-H30R/Rx subgroups underwent whole-genome sequencing (WGS) and phylogenetic analysis.

Results

E. coli from Iraq showed significantly higher resistance to all tested antibiotics compared to those from the USA, with 76.2% being FQREC versus 31.2% in the USA (p < 0.01). Iraqi FQREC strains were more frequently multidrug resistant. The predominant subgroup in both countries was ST131-H30, with the notable absence of ST1193 among Iraqi FQREC. Iraqi-origin ST131-H30 strains exhibited higher minimum inhibitory concentrations (MICs) for ciprofloxacin and greater resistance to third-generation cephalosporins (3GC), trimethoprim/sulfamethoxazole (TMP/STX), and imipenem (IMI) than those from the USA. Increased 3GC resistance in Iraqi strains was linked to a higher proportion of bla CTX-M-15-carrying H30Rx subclade isolates. Additionally, Iraqi H30 strains exhibited higher MICs for fluoroquinolones due to more frequent carriage of PMQR determinants compared to US strains. Whole-genome sequencing was performed on 46 Iraqi and 63 US H30 isolates. Phylogenetic analysis revealed two clades-H30R and H30Rx-present in both countries, with isolates from both regions distributed throughout, without the emergence of distinct new major subclones. However, Iraqi isolates tended to cluster in separate subclades, indicating endemic circulation of the strain groups.

Conclusion

In regions like Iraq, where antibiotics are overused and misused, resistance among uropathogenic E. coli to various antibiotics is significantly higher. Most Iraqi resistant strains belong to well-known international groups, and no new highly successful strains have emerged. The absence of ST1193 in Iraq may reflect regional, socioeconomic, demographic, or cultural factors that hinder the success of certain strain groups in the country.

Genomic Epidemiology of Multidrug-Resistant Escherichia coli and Klebsiella pneumoniae in Kenya, Uganda, and Jordan

Surveillance of antimicrobial resistance in Kenya, Uganda, and Jordan identified multidrug-resistant high-risk bacterial clones: Escherichia coli sequence types 131, 1193, 69, 167, 10, 648, 410, 405 and Klebsiella pneumoniae sequence types 14, 147, 307, 258. Clones emerging in those countries exhibited high resistance mechanism diversity, highlighting a serious threat for multidrug resistance.

Characterization of Gram-negative Bloodstream Infections in Hospitalized Australian Children and Their Clinical Outcomes

BACKGROUND

Gram-negative bloodstream infections (GNBSIs) more commonly occur in children with comorbidities and are increasingly associated with antimicrobial resistance. There are few large studies of GNBSIs in children that relate the clinical presentation, pathogen characteristics, and outcomes.

METHODS

A 3-year prospective study of GNBSIs in children aged <18 years was conducted in 5 Australian children's hospitals between 2019 and 2021. The clinical characteristics, disease severity, and outcomes were recorded. Causative pathogens underwent antibiotic susceptibility testing and whole genome sequencing.

RESULTS

There were 931 GNBSI episodes involving 818 children. Median age was 3 years (interquartile range, 0.6-8.5). A total of 576/931 episodes (62%) were community onset, though 661/931 (71%) occurred in children with comorbidities and a central venous catheter was present in 558/931 (60%). Central venous catheter (145/931) and urinary tract (149/931) were the most common sources (16% each). One hundred of 931 (11%) children required intensive care unit admission and a further 11% (105/931) developed GNBSIs in intensive care unit. A total of 659/927 (71%) isolates were Enterobacterales, of which 22% (138/630) were third-generation cephalosporin resistant (3GCR). Extended spectrum beta-lactamase genes were confirmed in 65/138 (47%) 3GCR Enterobacterales. Most common extended spectrum beta-lactamase genes were blaCTX-M-15 (34/94, 36%) and blaSHV-12 (10/94, 11%). There were 48 deaths overall and 30-day in-hospital mortality was 3% (32/931). Infections with 3GCR Enterobacterales were independently associated with higher mortality (adjusted odds ratio, 3.2; 95% confidence interval, 1.6-6.4).

CONCLUSIONS

GNBSIs in children are frequently healthcare associated and affect children younger than age 5 years. Infections with 3GCR Enterobacterales were associated with worse outcomes. These findings will inform optimal management guidelines and help prioritize future antimicrobial clinical trials.

Comprehensive Genomic Analysis of Uropathogenic E. coli: Virulence Factors, Antimicrobial Resistance, and Mobile Genetic Elements

Our whole-genome sequencing analysis of sixteen uropathogenic E. coli isolates revealed a concerning picture of multidrug resistance and potentially virulent bacteria. All isolates belonged to four distinct clonal groups, with the highly prevalent ST131 lineage being associated with extensive antibiotic resistance and virulence factors. Notably, all isolates exhibited multidrug resistance, with some resistant to as many as 12 antibiotics. Fluoroquinolone resistance stemmed primarily from efflux pumps and mutations in gyrase and topoisomerase genes. Additionally, we identified genes encoding resistance to extended-spectrum cephalosporins, trimethoprim/sulfamethoxazole, and various heavy metals. The presence of diverse plasmids and phages suggests the potential for horizontal gene transfer and the dissemination of virulence factors. All isolates harbored genomic islands containing virulence factors associated with adhesion, biofilm formation, and invasion. Genes essential for iron acquisition, flagella biosynthesis, secretion systems, and toxin production were also prevalent. Adding further complexity to understanding the isolates' genetic makeup, we identified CRISPR-Cas systems. This study underscores the need for continued genomic surveillance in understanding the pathogenic mechanisms and resistance profiles of uropathogenic E. coli to aid in developing targeted therapeutic strategies.

Increasing Fluroquinolone Susceptibility and Genetic Diversity of ESBL-Producing E. coli from the Lower Respiratory Tract during the COVID-19 Pandemic

Lower respiratory tract infections (LRTIs) are the fourth leading cause of death worldwide, among which Escherichia coli (E. coli) pneumonia is considered a rare phenomenon. Treatment options for LRTIs have become limited, especially for extended-spectrum β-lactamase-producing E. coli (ESBL-EC), which are usually resistant to other groups of antimicrobials as well. The aim of our study was to compare the phenotypic resistance profiles and genotypes of ESBL-EC isolates associated with LRTIs before (pre-COVID-19) and during (COVID-19) the COVID-19 pandemic. All isolates were screened for antimicrobial resistance genes (ARGs) and virulence-associated genes (VAGs) and assigned to phylogenetic groups, sequence types and clonal groups by PCR. During the pandemic, a significantly lower proportion of ciprofloxacin-, levofloxacin- and trimethoprim-sulfamethoxazole-resistant ESBL-EC isolates was retrieved from lower respiratory tract (LRT) samples. PCR-based genotypization revealed greater clonal diversity and a significantly lower proportion of isolates with blaTEM, aac(6')-Ib-cr and qacEΔ1 genes. In addition, a higher proportion of isolates with the integrase gene int1 and virulence genes sat and tsh was confirmed. The lower prevalence of fluoroquinolone resistance and greater genetic diversity of ESBL-EC isolated during the COVID-19 period may have been due to the introduction of new bacterial strains into the hospital environment, along with changes in clinical establishment guidelines and practices.

Escherichia coli ST1193 O75 H5: A rare cause of native valve endocarditis with multifocal emboli to brain and spleen

Escherichia coli (E. coli) is a facultative anaerobic gram-negative rod bacterium, which can acquire pathogenicity through the acquisition of additional genetic material. We present a case of E. coli ST1193, an emerging global multidrug-resistant (MDR) high-risk clone, causing native valve endocarditis and septic brain and splenic emboli in a 67-year-old woman.

The Scr and Csc pathways for sucrose utilization co-exist in E. coli, but only the Scr pathway is widespread in other Enterobacteriaceae

Most Escherichia coli isolates from humans do not utilize D-sucrose as a substrate for fermentation or growth. Previous work has shown that the Csc pathway allows some E. coli to utilize sucrose for slow growth, and this pathway has been engineered in E. coli W strains to enhance use of sucrose as a feedstock for industrial applications. An alternative sucrose utilization pathway, Scr, was first identified in Klebsiella pneumoniae and has been reported in some E. coli and Salmonella enterica isolates. We show here that the Scr pathway is native to an important subset of E. coli phylogroup B2 lineages that lack the Csc pathway but grow rapidly on sucrose. Laboratory E. coli strains derived from MG1655 (phylogroup A, ST10) are unable to utilize sucrose and lack the scr and csc genes, but a recombinant plasmid-borne scr locus enables rapid growth on and fermentation of sucrose. Genome analyses of Enterobacteriaceae indicate that the scr locus is widespread in other Enterobacteriaceae; including Enterobacter and Klebsiella species, and some Citrobacter and Proteus species. In contrast, the Csc pathway is limited mostly to E. coli, some Shigella species (in which csc loci are rendered non-functional by various mutations), and Citrobacter freundii. The more efficient Scr pathway likely has greater potential than the Csc pathway for bioindustrial applications of E. coli and other Enterobacteriaceae using sucrose as a feedstock.

Antimicrobial resistance and phylogenetic relatedness of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli in peridomestic rats (Rattus norvegicus and Rattus tanezumi) linked to city areas and animal farms in Hong Kong

Extended-spectrum β-lactamase-producing Escherichia (E.) coli (ESBL-EC) in the clinical setting have emerged as a major threat to public and animal health. Wildlife, including Rattus spp. may serve as reservoirs and spreaders of ESBL-EC in the environment. Peridomestic rats are well adapted to living in proximity to humans and animals in a variety of urban and agricultural environments and may serve as sentinels to identify variations of ESBL-EC within their different habitats. In this study, a set of 221 rats (Rattus norvegicus, R. tanezumi, R. andamanensis, and Niviventer huang) consisting of 104 rats from city areas, 44 from chicken farms, 52 from pig farms, and 21 from stables of horse-riding schools were screened for ESBL-EC. Overall, a total of 134 ESBL-EC were isolated from the caecal samples of 130 (59%) rats. The predominant blaESBL genes were blaCTX-M-14, blaCTX-M-15, blaCTX-M-55, and blaCTX-M-65. Phylogenetic analysis revealed a total of 62 sequence types (STs) and 17 SNP clusters. E. coli ST10 and ST155 were common to ESBL-EC from city areas and chicken farms, and ST44 were found among ESBL-EC from city areas and pig farms. Extra-intestinal pathogenic E. coli (ExPEC) ST69, ST131 and ST1193 were found exclusively among rats from city areas, and avian pathogenic E. coli (APEC) ST177 was restricted to ESBL-EC originating from chicken farms. Phylogenetic analysis showed that the populations of rodent ESBL-EC from city areas, chicken farms and pig farms were genetically different, suggesting a certain degree of partitioning between the human and animal locations. This study contributes to current understanding of ESBL-EC occurring in rats in ecologically diverse locations.

Longitudinal molecular analysis of clinical and fecal Escherichia coli isolates at a Veterans Affairs Medical Center in Minnesota, USA, 2012-2019

Introduction

Extraintestinal Escherichia coli infections represent a growing public health threat, However, current studies often overlook important factors such as temporal patterns of infection, phylogenetic and clonal background, or the host gut E. coli population, despite their likely significance.

Methods

In this study, we analyzed >7000 clinical E. coli isolates from patients at the Minneapolis Veterans Affairs Health Care System (2012-2019), and concurrent fecal E. coli from uninfected veterans. We assessed phylogenetic group distribution, membership in selected sequence types (STs), and subsets thereof-including the pandemic, resistance-associated ST131-H30R, and ST1193 lineages-and strain type, as defined by pulsed-field gel electrophoresis. We then analyzed these features alongside the temporal patterns of infection in individual hosts.

Results

The H30R lineage emerged as the leading lineage, both overall and among fluoroquinolone-resistant isolates, with ST1193 following among fluoroquinolone-resistant isolates. Recurrences were common, occurring in 31% of subjects and 41% of episodes, and often multiple and delayed/prolonged (up to 23 episodes per subject; up to 2655d post-index). Remarkably, these recurrences typically involved the subject's index strain (63% of recurrences), even when affecting extra-urinary sites. ST131, H30R, ST1193, and fluoroquinolone-resistant strains generally caused significantly more recurrences than did other strains, despite similar recurrence intervals. ST131 strain types shifted significantly over the study period. Infection-causing strains were commonly detectable in host feces at times other than during an infection episode; the likelihood of detection varied with surveillance intensity and proximity to the infection. H30R and ST1193 were prominent causes of fecal-clinical clonal overlap.

Discussion

These findings provide novel insights into the temporal and clonal characteristics of E. coli infections in veterans and support efforts to develop anti-colonization interventions.

Multidrug-resistant Escherichia coli causing canine pyometra and urinary tract infections are genetically related but distinct from those causing prostatic abscesses

Despite extensive characterisation of uropathogenic Escherichia coli (UPEC) causing urinary tract infections (UTIs), the genetic background of non-urinary extraintestinal pathogenic E. coli (ExPEC) in companion animals remains inadequately understood. In this study, we characterised virulence traits of 104 E. coli isolated from canine pyometra (n = 61) and prostatic abscesses (PAs) (n = 38), and bloodstream infections (BSIs) in dogs (n = 2), and cats (n = 3). A stronger association with UPEC of pyometra strains in comparison to PA strains was revealed. Notably, 44 isolates exhibited resistance to third-generation cephalosporins and/or fluoroquinolones, 15 were extended-spectrum ß-lactamase-producers. Twelve multidrug-resistant (MDR) strains, isolated from pyometra (n = 4), PAs (n = 5), and BSIs (n = 3), along with 7 previously characterised UPEC strains from dogs and cats, were sequenced. Genomic characteristics revealed that MDR E. coli associated with UTIs, pyometra, and BSIs belonged to international high-risk E. coli clones, including sequence type (ST) 38, ST131, ST617, ST648, and ST1193. However, PA strains belonged to distinct lineages, including ST12, ST44, ST457, ST744, and ST13037. The coreSNPs, cgMLST, and pan-genome illustrated intra-clonal variations within the same ST from different sources. The high-risk ST131 and ST1193 (phylogroup B2) contained high numbers of ExPEC virulence genes on pathogenicity islands, predominating in pyometra and UTI. Hybrid MDR/virulence IncF multi-replicon plasmids, containing aerobactin genes, were commonly found in non-B2 phylogroups from all sources. These findings offer genomic insights into non-urinary ExPEC, highlighting its potential for invasive infections in pets beyond UTIs, particularly with regards to high-risk global clones.

Colonization by Extended-Spectrum β-Lactamase-Producing Enterobacterales and Bacteremia in Hematopoietic Stem Cell Transplant Recipients

BACKGROUND

Assessing the risk of multidrug-resistant colonization and infections is pivotal for optimizing empirical therapy in hematopoietic stem cell transplants (HSCTs). Limited data exist on extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) colonization in this population. This study aimed to assess whether ESBL-E colonization constitutes a risk factor for ESBL-E bloodstream infection (BSI) and to evaluate ESBL-E colonization in HSCT recipients.

METHODS

A retrospective analysis of ESBL-E colonization and BSI in HSCT patients was conducted from August 2019 to June 2022. Weekly swabs were collected and cultured on chromogenic selective media, with PCR identifying the β-lactamase genes. Pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS) assessed the colonizing strains' similarities.

RESULTS

Of 222 evaluated HSCT patients, 59.45% were colonized by ESBL-E, with 48.4% at admission. The predominant β-lactamase genes were blaTEM (52%) and blaSHV (20%). PFGE analysis did not reveal predominant clusters in 26 E. coli and 15 K. pneumoniae strains. WGS identified ST16 and ST11 as the predominant sequence types among K. pneumoniae. Thirty-three patients developed thirty-five Enterobacterales-BSIs, with nine being third-generation cephalosporin-resistant. No association was found between ESBL-E colonization and ESBL-BSI (p = 0.087).

CONCLUSIONS

Although the patients presented a high colonization rate of ESBL-E upon admission, no association between colonization and infection were found. Thus, it seems that ESBL screening is not a useful strategy to assess risk factors and guide therapy for ESBL-BSI in HSCT-patients.

Assessment of three antibiotic combination regimens against Gram-negative bacteria causing neonatal sepsis in low- and middle-income countries

Gram-negative bacteria (GNB) are a major cause of neonatal sepsis in low- and middle-income countries (LMICs). Although the World Health Organization (WHO) reports that over 80% of these sepsis deaths could be prevented through improved treatment, the efficacy of the currently recommended first- and second-line treatment regimens for this condition is increasingly affected by high rates of drug resistance. Here we assess three well known antibiotics, fosfomycin, flomoxef and amikacin, in combination as potential antibiotic treatment regimens by investigating the drug resistance and genetic profiles of commonly isolated GNB causing neonatal sepsis in LMICs. The five most prevalent bacterial isolates in the NeoOBS study (NCT03721302) are Klebsiella pneumoniae, Acinetobacter baumannii, E. coli, Serratia marcescens and Enterobacter cloacae complex. Among these isolates, high levels of ESBL and carbapenemase encoding genes are detected along with resistance to ampicillin, gentamicin and cefotaxime, the current WHO recommended empiric regimens. The three new combinations show excellent in vitro activity against ESBL-producing K. pneumoniae and E. coli isolates. Our data should further inform and support the clinical evaluation of these three antibiotic combinations for the treatment of neonatal sepsis in areas with high rates of multidrug-resistant Gram-negative bacteria.

Detecting Class 1 Integrons and Their Variable Regions in Escherichia coli Whole-Genome Sequences Reported from Andean Community Countries

Various genetic elements, including integrons, are known to contribute to the development of antimicrobial resistance. Class 1 integrons have been identified in E. coli isolates and are associated with multidrug resistance in countries of the Andean Community. However, detailed information on the gene cassettes located on the variable regions of integrons is lacking. Here, we investigated the presence and diversity of class 1 integrons, using an in silico approach, in 2533 whole-genome sequences obtained from EnteroBase. IntFinder v1.0 revealed that almost one-third of isolates contained these platforms. Integron-bearing isolates were associated with environmental, food, human, and animal origins reported from all countries under scrutiny. Moreover, they were identified in clones known for their pathogenicity or multidrug resistance. Integrons carried cassettes associated with aminoglycoside (aadA), trimethoprim (dfrA), cephalosporin (blaOXA; blaDHA), and fluoroquinolone (aac(6')-Ib-cr; qnrB) resistance. These platforms showed higher diversity and larger numbers than previously reported. Moreover, integrons carrying more than three cassettes in their variable regions were determined. Monitoring the prevalence and diversity of genetic elements is necessary for recognizing emergent patterns of resistance in pathogenic bacteria, especially in countries where various factors are recognized to favor the selection of resistant microorganisms.

Gut resident Escherichia coli profile predicts the eighteen-month probability and antimicrobial susceptibility of urinary tract infections

Background

Community-acquired UTI is the most common bacterial infection managed in general medical practice that can lead to life-threatening outcomes. While UTIs are primarily caused by Escherichia coli colonizing the patient's gut, it is unclear whether the gut resident E. coli profiles can predict the person's risks for UTI and optimal antimicrobial treatments. Thus, we conducted an eighteen-month long community-based observational study of fecal E. coli colonization and UTI in women aged 50 years and above.

Methods and Findings

We enrolled a total of 1,804 women distributed among age groups 50-59 yo (437 participants), 60-69 yo (632), 70-79 yo (532), and above 80 yo (203), lacking antibiotic prescriptions for at least one year. The provided fecal samples were plated for the presence of E. coli and other enterobacteria resistant to trimethoprim/sulfamethoxazole (TMP/STX), ciprofloxacin (CIP) and 3rd generation cephalosporins (3GC). E. coli was also characterized as belonging to the pandemic multi-drug resistant clonal groups ST131 (subclone H30) and ST1193. Following sample collection, the women were monitored for 18 months for occurrence of UTI.E. coli was cultured from 90.8% fecal samples, with 24.1% containing bacteria resistant to TMP/STX, 19.4% to CIP, and 7.9% to 3GC. In 62.5% samples, only all-susceptible E. coli were present. Overall, there were no age-related differences in resistance prevalence. However, while the total E. coli H30 and ST1193 carriage rates were similar (4.3% and 4.2%, respectively), there was a notable increase of H30 carriage with age (P = .001), while carriage decreased with age for ST1193 (P = .057).Within 18 months, 184 women (10.2%) experienced at least one episode of UTI - 10.9% among the gut E. coli carriers and 3.0% among the non-carriers (P=.0013). The UTI risk among carriers of E. coli H30 but not ST1193 was significantly above average (24.3%, P = .0004). The UTI probability increased with age, occurring in 6.4% of 50-59 yo and 19.7% of 80+ yo (P<.001), with the latter group being especially at high risk for UTI, if they were colonized by E. coli H30 (40.0%, P<.001).E. coli was identified in 88.1% of urine samples, with 16.1% resistant to TMP/STX, 16.1% to CIP, 4.2% to 3GC and 73.1% to none of the antibiotics. Among tested urinary E. coli resistant to antibiotics, 86.1% matched the resistance profile of E. coli in the fecal samples, with the clonotyping and whole genome sequencing confirming the matching strains' identity. Positive predictive value (PPV) of using gut resistance profiles to predict UTI pathogens' susceptibility to TMP/STX, CIP, 3GC and all three antibiotics were 98.4%, 98.3%, 96.6% and 95.3%, respectively. Corresponding negative predictive values (NPV) were 63.0%, 54.8%, 44.4% and 75.8%, respectively. The AUC ROC curve values for the accuracy of fecal diagnostic testing for the prediction of UTI resistance ranged .86-.89. The fecal test-guided drug-bug mismatch rate for empirical (pre-culture) prescription of TMP-SXT or CIP is reduced to ≤2% in 89.6% of patients and 94.8% of patients with an optional 3GC prescription.

Conclusion

The resistance profile and clonal identity of gut colonizing E. coli, along with the carrier's age, can inform personalized prediction of a patients' UTI risk and the UTI pathogen's antibiotic susceptibility within an 18-month period.

Clinical validation of loop-mediated isothermal amplification for the detection of Escherichia coli sequence type complex 131

The dissemination of Escherichia coli multidrug-resistant (MDR) STc131 is related to its persistence in the human gastrointestinal tract as efficient gut colonizers. Infection and prevention measures are the cornerstones for preventing STc131 spread. Oral decolonization therapies that target ST131 are being developed. There are no rapid methods available to identify STc131 in human specimens. A loop-mediated isothermal amplification (LAMP) assay (named LAMP-ST131) was developed for the detection of STc131 on well-characterized E. coli isolates and then compared to culture and PCR for urines and stool swabs. With E. coli isolates (n = 720), LAMP-ST131 had a sensitivity (sens) of 100% [95% confidence interval (C.I.) = 98.1-100%)] and a specificity (spec) of 98.9% (95% C.I. = 97.5-99.5%). On urines (n = 550), LAMP-ST131 had a sens of 97.6% (95% C.I. = 89.68-94.33%) and a spec of 92.3% (95% C.I. = 87.68-99.88%), while on stool swabs (n = 278), LAMP-ST131 had a sens of 100% (95% C.I. = 88.7-100%) and a spec of 83.9% (95% C.I. = 78.8-87.9%). LAMP-ST131 detected 10 (urines) and 100 (stool swabs) gene copies/μL. LAMP-ST131 accurately identified STc131 within E. coli isolates and human specimens. The implementation of LAMP-ST131 will aid genomic surveys, enable the rapid implementation of effective infection prevention measures, and identify patients suitable for ST131 decolonization therapies. Such approaches will curb the spread of STc131 and decrease incidence rates of global MDR E. coli infections.

IMPORTANCE

We developed an accurate non-culture-based loop-mediated isothermal amplification (LAMP) methodology for the detection of (sequence type) STc131 among Escherichia coli isolates and human specimens. The use of LAMP-ST131 for global genomic surveillance studies and to identify patients that are suitable for ST131 decolonization therapies will be important for decreasing multidrug-resistant E. coli infections across the globe.

Fluoroquinolone resistance in complicated urinary tract infections: association with the increased occurrence and diversity of Escherichia coli of clonal complex 131, together with ST1193

Introduction

Urinary tract infections (UTIs) are one of the leading causes of multidrug-resistance (MDR) spread and infection-related deaths. Escherichia coli is by far the main causative agent. We conducted a prospective study on complicated urinary tract infections (cUTIs) i) to monitor the high-risk clones that could be compromising the therapeutic management and ii) to compare the cUTI etiology with uncomplicated infections (uUTIs) occurring in the same period and health area.

Methods

154 non-duplicated E. coli recovered from cUTIs in 2020 at the Hospital Universitario Central de Asturias (Spain) constituted the study collection.

Results

Most cUTI isolates belonged to phylogroup B2 (72.1%) and met the uropathogenic (UPEC) status (69.5%) (≥3 of chuA, fyuA, vat, and yfcV genes). MDR was exhibited by 35.7% of the isolates, similarly to data observed in the uUTI collection. A significant difference observed in cUTI was the higher level of fluoroquinolone resistance (FQR) (47.4%), where the pandemic clonal groups B2-CC131 and B2-ST1193 (CH14-64) comprised 28% of the 154 E. coli, representing 52.1% of the FQR isolates. Other prevalent FQR clones were D-ST69 (CH35-27), D-ST405 (CH37-27), and B2-ST429 (CH40-20) (three isolates each). We uncovered an increased genetic and genomic diversity of the CC131: 10 different virotypes, 8 clonotypes (CH), and 2 STs. The presence of bla CTX-M-15 was determined in 12 (7.8%) isolates (all CC131), which showed 10 different core genome (cg)STs and 2 fimH types (fimH30 and fimH602) but the same set of chromosomal mutations conferring FQR (gyrA p.S83L, gyrA p.D87N, parC p.S80I, parC p.E84V, and parE p.I529L). In addition, the plasmidome analysis revealed 10 different IncF formulae in CC131 genomes.

Conclusion

We proved here that non-lactose fermenting screening, together with the detection of O25b (rfbO25b), H4 (fliCH4), and H5 (fliCH5) genes, and phylogroup and clonotyping assignation, is a reasonable approach that can be easily implemented for the surveillance of emerging high-risk clones associated with FQR spread in cUTIs, such as the uncommonly reported O25b:H4-B2-ST9126-CC131 (CH1267-30). Since E. coli CC131 and ST1193 are also involved in the community uUTIs of this health area, interventions to eradicate these MDR clones, along with surveillance for other emerging ones, are essential for antibiotic use optimization programs.

Escherichia coli sequence type 410 with carbapenemases: a paradigm shift within E. coli toward multidrug resistance

Escherichia coli sequence type ST410 is an emerging carbapenemase-producing multidrug-resistant (MDR) high-risk One-Health clone with the potential to significantly increase carbapenem resistance among E. coli. ST410 belongs to two clades (ST410-A and ST410-B) and three subclades (ST410-B1, ST410-B2, and ST410-B3). After a fimH switch between clades ST410-A and ST410-B1, ST410-B2 and ST410-B3 subclades showed a stepwise progression toward developing MDR. (i) ST410-B2 initially acquired fluoroquinolone resistance (via homologous recombination) in the 1980s. (ii) ST410-B2 then obtained CMY-2, CTX-M-15, and OXA-181 genes on different plasmid platforms during the 1990s. (iii) This was followed by the chromosomal integration of blaCMY-2, fstl YRIN insertion, and ompC/ompF mutations during the 2000s to create the ST410-B3 subclade. (iv) An IncF plasmid "replacement" scenario happened when ST410-B2 transformed into ST410-B3: F36:31:A4:B1 plasmids were replaced by F1:A1:B49 plasmids (both containing blaCTX-M-15) followed by blaNDM-5 incorporation during the 2010s. User-friendly cost-effective methods for the rapid identification of ST410 isolates and clades are needed because limited data are available about the frequencies and global distribution of ST410 clades. Basic mechanistic, evolutionary, surveillance, and clinical studies are urgently required to investigate the success of ST410 (including the ability to acquire successive MDR determinants). Such information will aid with management and prevention strategies to curb the spread of carbapenem-resistant E. coli. The medical community can ill afford to ignore the spread of a global E. coli clone with the potential to end the carbapenem era.

Comparative genomic analysis of uropathogenic Escherichia coli strains from women with recurrent urinary tract infection

Introduction

Recurrent urinary tract infections (RUTIs) caused by uropathogenic Escherichia coli are costly public health problems impacting patients' quality of life.

Aim

In this work, a comparative genomics analysis of three clinical RUTI strains isolated from bladder biopsy specimens was performed.

Materials and methods

One hundred seventy-two whole genomes of urinary tract E. coli strains were selected from the NCBI database. The search for virulence factors, fitness genes, regions of interest, and genetic elements associated with resistance was manually carried out. The phenotypic characterization of antibiotic resistance, haemolysis, motility, and biofilm formation was performed. Moreover, adherence and invasion assays with human bladder HTB-5 cells, and transmission electron microscopy (TEM) were performed.

Results

The UTI-1_774U and UTI-3_455U/ST1193 strains were associated with the extraintestinal pathotypes, and the UTI-2_245U/ST295 strain was associated with the intestinal pathotype, according to a phylogenetic analysis of 172 E. coli urinary strains. The three RUTI strains were of clinical, epidemiological, and zoonotic relevance. Several resistance genes were found within the plasmids of these strains, and a multidrug resistance phenotype was revealed. Other virulence genes associated with CFT073 were not identified in the three RUTI strains (genes for type 1 and P fimbriae, haemolysin hlyA, and sat toxin). Quantitative adherence analysis showed that UTI-1_774U was significantly (p < 0.0001) more adherent to human bladder HTB-5 cells. Quantitative invasion analysis showed that UTI-2_245U was significantly more invasive than the control strains. No haemolysis or biofilm activity was detected in the three RUTI strains. The TEM micrographs showed the presence of short and thin fimbriae only in the UTI-2_245U strain.

Conclusion

The high variability and genetic diversity of the RUTI strains indicate that are a mosaic of virulence, resistance, and fitness genes that could promote recurrence in susceptible patients.

CRISPR-Cas9-mediated IncF plasmid curing in extraintestinal pathogenic Escherichia coli

IMPORTANCE

Understanding the role of IncF plasmids in the success of drug-resistant bacteria has far-reaching implications for tackling antibiotic resistance. The study's use of a novel CRISPR-Cas9-mediated plasmid-curing system provides a precision tool for dissecting the specific impact of IncF plasmids on ExPEC clones, especially high-risk, multidrug-resistant strains like ST131, ST1193, and ST410. The study offers a crucial stepping stone for future research into understanding how these plasmids influence more complex aspects of bacterial behavior, such as cell invasion and in vivo fitness.

Early-Onset Infection Caused by Escherichia coli Sequence Type 1193 in Late Preterm and Full-Term Neonates

Using whole-genome sequencing, we characterized Escherichia coli strains causing early-onset sepsis (EOS) in 32 neonatal cases from a 2019-2021 prospective multicenter study in France and compared them to E. coli strains collected from vaginal swab specimens from women in third-trimester gestation. We observed no major differences in phylogenetic groups or virulence profiles between the 2 collections. However, sequence type (ST) analysis showed the presence of 6/32 (19%) ST1193 strains causing EOS, the same frequency as in the highly virulent clonal group ST95. Three ST1193 strains caused meningitis, and 3 harbored extended-spectrum β-lactamase. No ST1193 strains were isolated from vaginal swab specimens. Emerging ST1193 appears to be highly prevalent, virulent, and antimicrobial resistant in neonates. However, the physiopathology of EOS caused by ST1193 has not yet been elucidated. Clinicians should be aware of the possible presence of E. coli ST1193 in prenatal and neonatal contexts and provide appropriate monitoring and treatment.

Genomic surveillance of antimicrobial-resistant Escherichia coli in fecal sludge and sewage in Uganda

The global increase of antimicrobial resistance (AMR) is a major public health concern. An effective AMR surveillance tool is needed to track the emergence and spread of AMR. Wastewater surveillance has been proposed as a resource-efficient tool for monitoring AMR carriage in the community. Here, we performed genomic surveillance of antimicrobial-resistant Escherichia coli obtained from fecal sludge and sewage in Uganda to gain insights into E. coli epidemiology and AMR burden in the underlying population. Selective media containing different antibiotic combinations (cefotaxime, ciprofloxacin, cefotaxime + ciprofloxacin + gentamicin) were used to obtain antimicrobial-resistant E. coli from fecal sludge and sewage. Short-read sequencing was performed for the obtained isolates, and a subset of isolates (selected from predominant sequence types (STs)) was also subjected to long-read sequencing. Genomic analysis of the obtained E. coli isolates (n = 181) revealed the prevalence of clonal complex 10, including ST167 (n = 43), ST10 (n = 28), ST1284 (n = 17), and ST617 (n = 4), in both fecal sludge and sewage, irrespective of antibiotics used for selection. We also detected global high-risk clones ST1193 (n = 10) and ST131 (n = 2 clade A, n = 3 subclade C1-M27, and n = 1 subclade C2). Diverse AMR determinants, including extended-spectrum β-lactamase genes (mostly blaCTX-M-15) and mutations in gyrA and parC, were identified. Analysis of the completed genomes revealed that diverse IncF plasmids and chromosomal integration were the major contributors to the spread of AMR genes in the predominant STs. This study showed that a combination of sewage surveillance (or fecal sludge surveillance) and whole-genome sequencing can be a powerful tool for monitoring AMR carriage in the underlying population.

The scope of antimicrobial resistance in residential aged care facilities determined through analysis of Escherichia coli and the total wastewater resistome

IMPORTANCE

Antimicrobial resistance (AMR) is a global threat that imposes a heavy burden on our health and economy. Residential aged care facilities (RACFs), where frequent inappropriate antibiotic use creates a selective environment that promotes the development of bacterial resistance, significantly contribute to this problem. We used wastewater-based epidemiology to provide a holistic whole-facility assessment and comparison of antimicrobial resistance in two RACFs and a retirement village. Resistant Escherichia coli, a common and oftentimes problematic pathogen within RACFs, was isolated from the wastewater, and the phenotypic and genotypic AMR was determined for all isolates. We observed a high prevalence of an international high-risk clone, carrying an extended-spectrum beta-lactamase in one facility. Analysis of the entire resistome also revealed a greater number of mobile resistance genes in this facility. Finally, both facilities displayed high fluoroquinolone resistance rates-a worrying trend seen globally despite measures in place aimed at limiting their use.

The role of the plasmid-mediated fluoroquinolone resistance genes as resistance mechanisms in pediatric infections due to Enterobacterales

Introduction

Fluoroquinolones (FQs) are not commonly prescribed in children, yet the increasing incidence of multidrug-resistant (MDR) Enterobacterales (Ent) infections in this population often reveals FQ resistance. We sought to define the role of FQ resistance in the epidemiology of MDR Ent in children, with an overall goal to devise treatment and prevention strategies.

Methods

A case-control study of children (0-18 years) at three Chicago hospitals was performed. Cases had infections by FQ-susceptible, β-lactamase-producing (bla) Ent harboring a non- or low-level expression of PMFQR genes (PMFQS Ent). Controls had FQR infections due to bla Ent with expressed PMFQR genes (PMFQR Ent). We sought bla genes by PCR or DNA (BD Max Check-Points assay®) and PMFQR genes by PCR. We performed rep-PCR, MLST, and E. coli phylogenetic grouping. Whole genome sequencing was additionally performed on PMFQS Ent positive isolates. Demographics, comorbidities, and device, antibiotic, and healthcare exposures were evaluated. Predictors of infection were assessed.

Results

Of 170 β-lactamase-producing Ent isolates, 85 (50%) were FQS; 23 (27%) had PMFQR genes (PMFQS cases). Eighty-five (50%) were FQR; 53 (62%) had PMFQR genes (PMFQR controls). The median age for children with PMFQS Ent and PMFQR Ent was 4.3 and 6.2 years, respectively (p = NS). Of 23 PMFQS Ent, 56% were Klebsiella spp., and of 53 PMFQR Ent, 76% were E. coli. The most common bla and PMFQR genes detected in PMFQS Ent were bla SHV ESBL (44%) and oqxAB (57%), and the corresponding genes detected in PMFQR Ent were bla CTX-M-1-group ESBL (79%) and aac(6')-Ib-cr (83%). Whole genome sequencing of PMFQS Ent revealed the additional presence of mcr-9, a transferable polymyxin resistance gene, in 47% of isolates, along with multiple plasmids and mobile genetic elements propagating drug resistance. Multivariable regression analysis showed that children with PMFQS Ent infections were more likely to have hospital onset infection (OR 5.7, 95% CI 1.6-22) and isolates containing multiple bla genes (OR 3.8, 95% CI 1.1-14.5). The presence of invasive devices mediated the effects of healthcare setting in the final model. Differences in demographics, comorbidities, or antibiotic use were not found.

Conclusions

Paradoxically, PMFQS Ent infections were often hospital onset and PMFQR Ent infections were community onset. PMFQS Ent commonly co-harbored multiple bla and PMFQR genes, and additional silent, yet transferrable antibiotic resistance genes such as mcr-9, affecting therapeutic options and suggesting the need to address infection prevention strategies to control spread. Control of PMFQS Ent infections will require validating community and healthcare-based sources and risk factors associated with acquisition.

Commensal Fitness Advantage May Contribute to the Global Dissemination of Multidrug-Resistant Lineages of Bacteria-The Case of Uropathogenic E. coli

It is widely accepted that favorable fitness in commensal colonization is one of the prime facilitators of clonal dissemination in bacteria. The question arises as to what kind of fitness advantage may be wielded by uropathogenic strains of the two predominant fluoroquinolone- and multidrug-resistant clonal groups of E. coli-ST131-H30 and ST1193, which has permitted their unprecedented pandemic-like global expansion in the last few decades. The colonization-associated genes' content, carriage of low-cost plasmids, and integrons with weak promoters could certainly contribute to the fitness of the pandemic groups, although those genetic factors are common among other clonal groups as well. Also, ST131-H30 and ST1193 strains harbor fluoroquinolone-resistance conferring mutations targeting serine residues in DNA gyrase (GyrA-S83) and topoisomerase IV (ParC-S80) that, in those clonal backgrounds, might result in a commensal fitness benefit, i.e., beyond the antibiotic resistance per se. This fitness gain might have contributed not only to the widespread dissemination of these major clones in the healthcare setting but also to their long-term colonization of healthy individuals and, thus, circulation in the community, even in a low or no fluoroquinolone use environment. This evolutionary shift affecting commensal E. coli, initiated by mutations co-favorable in both antibiotics-treated patients and healthy individuals warrants more in-depth studies to monitor further changes in the epidemiological situation and develop effective measures to reduce the antibiotic resistance spread.

Genomic Characteristics of Extended Spectrum β-Lactamase Producing Escherichia coli Isolates Recovered from a District Hospital in China

Purpose

The isolation rate of extended spectrum β-lactamase (ESBL)-producing Escherichia coli is increasing, posing a challenge to clinical anti-infective therapy. This study aims to provide new insight into the genomic characteristics and antimicrobial resistance mechanisms of extended spectrum β-lactamase producing E. coli isolates recovered from a district hospital in China.

Methods

A total of 36 ESBL-producing E. coli isolates were collected from body fluid samples from a Chinese district hospital. All isolates were subjected to whole genome sequencing to identify their antimicrobial resistance genes, virulence genes, serotypes, sequence types, and phylogenetic relationships by BacWGSTdb 2.0 webserver.

Results

Among these isolates, all were resistant to cefazolin, cefotaxime, ceftriaxone, ampicillin, 24 (66.7%) were resistant to aztreonam, 16 (44.4%) were resistant to cefepime, and 15 were resistant (41.7%) to ceftazidime. The bla_CTX-M gene was detected in all ESBL-producing E. coli isolates. Two isolates carrying two different types of bla_CTX-M genes simultaneously. The carbapenem resistance gene bla_KPC-2 was detected in one (2.8%) isolate. A total of 17 sequence types (STs) were found, with ST131 accounting for the majority (n =13; 36.1%). The most common serotype was O16:H5 associated with seven ST131 strains, followed by O25:H4/ST131 (n = 5) and O75:H5/ST1193 (n = 5). Evaluation of clonal relatedness revealed that all bla_CTX-M gene-carrying E. coli had a difference of SNPs range from 7 to 79,198, which could be divided into four clusters. Only 7 SNPs could be found between EC266 and EC622, indicating that they are variants of the same clonal lineage.

Conclusion

This study investigated the genomic characteristics of ESBL-producing E. coli isolates recovered from a district hospital in China. Continuous surveillance of ESBL-producing E. coli infections is imperative to create efficient strategies for controlling the transmission of these multi-drug resistant bacteria in clinical and community settings.

Antibiotic susceptibility of Escherichia coli isolated from neonates admitted to neonatal intensive care units across China from 2015 to 2020

Background

Escherichia coli is one of the most common pathogens causing neonatal infections. Recently, the incidence and drug resistance of E. coli have increased, posing a major threat to neonatal health. The aim of this study was to describe and analyze the antibiotic resistance and multilocus sequence typing (MLST) characteristics of E. coli derived from infants admitted to neonatal intensive care units (NICUs) across China.

Methods

In this study, 370 strains of E. coli from neonates were collected. E. coli isolated from these specimens were subjected to antimicrobial susceptibility testing (by broth microdilution method) and MLST.

Results

The overall resistance rate was 82.68%, with the highest rate of methicillin/sulfamethoxazole (55.68%) followed by cefotaxime (46.22%). Multiple resistance rate was 36.74%, 132 strains (35.68%) had extended-spectrum β-lactamase (ESBL) phenotype and 5 strains (1.35%) had insensitivity to the tested carbapenem antibiotics. The resistance of E. coli isolated from different pathogenicity and different sites of infections varied, strains derived from sputum were significantly more resistant to β-lactams and tetracyclines. Currently, the prevalence spectrum in NICUs was dominated by ST1193, ST95, ST73, ST69 and ST131 across China. And the multidrug resistance of ST410 was the most severe. ST410 had the highest resistance rate to cefotaxime (86.67%), and its most common multidrug resistance pattern was β-lactams + aminoglycosides + quinolones + tetracyclines + sulfonamides.

Conclusions

Substantial proportions of neonatal E. coli isolates were severely resistant to commonly administered antibiotics. MLST results can suggest the prevalent characteristics of antibiotic resistance in E. coli with different ST types.

Genomic Characterization of Uropathogenic Escherichia coli Isolates from Tertiary Hospitals in Riyadh, Saudi Arabia

Uropathogenic Escherichia coli (UPEC) is the most common cause of urinary tract infections (UTIs) in hospitalised and non-hospitalised patients. Genomic analysis was used to gain further insight into the molecular characteristics of UPEC isolates from Saudi Arabia. A total of 165 isolates were collected from patients with UTIs between May 2019 and September 2020 from two tertiary hospitals in Riyadh, Saudi Arabia. Identification and antimicrobial susceptibility testing (AST) were performed using the VITEK system. Extended-spectrum β-lactamase (ESBL)-producing isolates (n = 48) were selected for whole genome sequencing (WGS) analysis. In silico analysis revealed that the most common sequence types detected were ST131 (39.6%), ST1193 (12.5%), ST73 (10.4%), and ST10 (8.3%). Our finding showed that blaCTX-M-15 gene was detected in the majority of ESBL isolates (79.2%), followed by blaCTX-M-27 (12.5%) and blaCTX-M-8 (2.1%). ST131 carried blaCTX-M-15 or blaCTX-M-27, and all ST73 and ST1193 carried blaCTX-M-15. The relatively high proportion of ST1193 in this study was notable as a newly emerged lineage in the region, which warrants further monitoring.

The contributions of multidrug resistant clones to the success of pandemic extra-intestinal Pathogenic Escherichia coli

INTRODUCTION

High-risk multidrug (MDR) clones have played essential roles in the global emergence and spread of antimicrobial resistance (AMR), especially among Extra-intestinal Escherichia coli (ExPEC).

AREAS COVERED

Successful global ExPEC MDR clones are linked with the acquisition of fluoroquinolone resistance, CTX-M enzymes, and with carbapenemases. This article described the underlying mechanisms of fluoroquinolone resistance, the acquisition of CTX-M and carbapenemase genes among three global ExPEC high-risk MDR clones, namely i) ST1193 as being an example of a fluoroquinolone resistant clone. ii) ST131 as an example of a fluoroquinolone resistant and CTX-M clone. iii) ST410 as an example of a fluoroquinolone resistant, CTX-M and carbapenemase clone. This article also highlighted the contributions of these MDR determinants in the evolution of these high-risk MDR clones.

EXPERT OPINION

There is an enormous public health burden due to E. coli MDR high-risk clones such as ST1193, ST131 and ST410. These clones have played pivotal roles in the global spread of AMR. Sparse information is available on which specific features of these high-risk MDR clones have enabled them to become such successful global pathogens in relative short time periods.

Antibacterial Efficacy of N-(4-methylpyridin-2-yl) Thiophene-2-Carboxamide Analogues against Extended-Spectrum-β-Lactamase Producing Clinical Strain of Escherichia coli ST 131

Development in the fields of natural-product-derived and synthetic small molecules is in stark contrast to the ongoing demand for novel antimicrobials to treat life-threatening infections caused by extended-spectrum β-lactamase producing Escherichia coli (ESBL E. coli). Therefore, there is an interest in the antibacterial activities of synthesized N-(4-methylpyridin-2-yl) thiophene-2-carboxamides (4a–h) against ESBL-producing E. coli ST131 strains. A blood sample was obtained from a suspected septicemia patient and processed in the Bactec Alert system. The isolate’s identification and antibacterial profile were determined using the VITEK 2® compact system. Multi-locus sequence typing of E. coli was conducted by identifying housekeeping genes, while ESBL phenotype detection was performed according to CLSI guidelines. Additionally, PCR was carried out to detect the blaCTX-M gene molecularly. Moreover, molecular docking studies of synthesized compounds (4a–h) demonstrated the binding pocket residues involved in the active site of the β-lactamase receptor of E. coli. The result confirmed the detection of E. coli ST131 from septicemia patients. The isolates were identified as ESBL producers carrying the blaCTX-M gene, which provided resistance against cephalosporins and beta-lactam inhibitors but sensitivity to carbapenems. Among the compounds tested, 4a and 4c exhibited high activity and demonstrated the best fit and interactions with the binding pocket of the β-lactamase enzyme. Interestingly, the maximum of the docking confirmations binds at a similar pocket region, further strengthening the importance of binding residues. Hence, the in vitro and molecular docking studies reflect the promising antibacterial effects of 4a and 4c compounds.

The Significance of Epidemic Plasmids in the Success of Multidrug-Resistant Drug Pandemic Extraintestinal Pathogenic Escherichia coli

Epidemic IncF plasmids have been pivotal in the selective advantage of multidrug-resistant (MDR) extraintestinal pathogenic Escherichia coli (ExPEC). These plasmids have offered several advantages to their hosts that allowed them to coevolve with the bacterial host genomes and played an integral role in the success of ExPEC. IncF plasmids are large, mosaic, and often contain various types of antimicrobial resistance (AMR) and virulence associated factor (VAF) genes. The presence of AMR, VAF genes, several addition/restriction systems combined with truncated transfer regions, led to the fixation of IncF plasmids in certain ExPEC MDR clones, such as ST131 and ST410. IncF plasmids entered the ST131 ancestral lineage in the mid 1900s and different ST131 clade/CTX-M plasmid combinations coevolved over time. The IncF_CTX-M-15/ST131-C2 subclade combination emerged during the early 2000s, spread rapidly across the globe, and is one of the greatest clone/plasmid successes of the millennium. The ST410-B3 subclade containing bla_CTX-M-15 incorporated the NDM-5 carbapenemase gene into existing IncF platforms, providing an additional positive selective advantage that included the carbapenems. A "plasmid-replacement" clade scenario occurred in the histories of ST131 and ST410 as different subclades gained different AMR genes on different IncF platforms. The use of antimicrobial agents will generate selection pressures that enhance the risks for the continuous emergence of MDR ExPEC clone/IncF plasmid combinations. The reasons for clade/IncF replacements and associations between certain clades and specific IncF plasmid types are unknown. Such information will aid in designing management and prevention strategies to combat AMR.

Molecular surveillance of multidrug-resistant Gram-negative bacteria in Ukrainian patients, Germany, March to June 2022

BackgroundSince the beginning of the war in Ukraine in February 2022, Ukrainians have been seeking shelter in other European countries.AimWe aimed to investigate the prevalence and the molecular epidemiology of multidrug-resistant Gram-negative (MDRGN) bacteria and meticillin-resistant Staphylococcus aureus (MRSA) in Ukrainian patients at admittance to the University Hospital Frankfurt, Germany.MethodsWe performed screening and observational analysis of all patients from March until June 2022. Genomes of MDRGN isolates were analysed for antimicrobial resistance, virulence genes and phylogenetic relatedness.ResultsWe included 103 patients (median age: 39 ± 23.7 years), 57 of whom were female (55.3%; 95% confidence interval (CI): 45.2-5.1). Patients were most frequently admitted to the Department of Paediatrics (29/103; 28.2%; 95% CI: 19.7-37.9). We found 34 MDRGN isolates in 17 of 103 patients (16.5%; 95% CI: 9.9-25.1). Ten patients carried 21 carbapenem-resistant (CR) bacteria, five of them more than one CR isolate. Four of six patients with war-related injuries carried eight CR isolates. In six of 10 patients, CR isolates caused infections. Genomic characterisation revealed that the CR isolates harboured at least one carbapenemase gene, bla _NDM-1 being the most frequent (n = 10). Core genome and plasmid analysis revealed no epidemiological connection between most of these isolates. Hypervirulence marker genes were found in five of six Klebsiella pneumoniae CR isolates. No MRSA was found.ConclusionHospitals should consider infection control strategies to cover the elevated prevalence of MDRGN bacteria in Ukrainian patients with war-related injuries and/or hospital pre-treatment and to prevent the spread of hypervirulent CR isolates.

Emergence and Dissemination of Extraintestinal Pathogenic High-Risk International Clones of Escherichia coli

Multiresistant Escherichia coli has been disseminated worldwide, and it is one of the major causative agents of nosocomial infections. E. coli has a remarkable and complex genomic plasticity for taking up and accumulating genetic elements; thus, multiresistant high-risk clones can evolve. In this review, we summarise all available data about internationally disseminated extraintestinal pathogenic high-risk E. coli clones based on whole-genome sequence (WGS) data and confirmed outbreaks. Based on genetic markers, E. coli is clustered into eight phylogenetic groups. Nowadays, the E. coli ST131 clone from phylogenetic group B2 is the predominant high-risk clone worldwide. Currently, strains of the C1-M27 subclade within clade C of ST131 are circulating and becoming prominent in Canada, China, Germany, Hungary and Japan. The C1-M27 subclade is characterised by bla_CTX-M-27. Recently, the ST1193 clone has been reported as an emerging high-risk clone from phylogenetic group B2. ST38 clone carrying bla_OXA-244 (a bla_OXA-48-like carbapenemase gene) caused several outbreaks in Germany and Switzerland. Further high-risk international E. coli clones include ST10, ST69, ST73, ST405, ST410, ST457. High-risk E. coli strains are present in different niches, in the human intestinal tract and in animals, and persist in environment. These strains can be transmitted easily within the community as well as in hospital settings. WGS analysis is a useful tool for tracking the dissemination of resistance determinants, the emergence of high-risk mulitresistant E. coli clones and to analyse changes in the E. coli population on a genomic level.

Oral ciprofloxacin activity against ceftriaxone-resistant Escherichia coli in an in vitro bladder infection model

OBJECTIVES

Pharmacodynamic profiling of oral ciprofloxacin dosing for urinary tract infections caused by ceftriaxone-resistant Escherichia coli isolates with ciprofloxacin MIC ≥ 0.25 mg/L.

BACKGROUND

Urine-specific breakpoints for ciprofloxacin do not exist. However, high urinary concentrations may promote efficacy in isolates with low-level resistance.

METHODS

Ceftriaxone-resistant E. coli urinary isolates were screened for ciprofloxacin susceptibility. Fifteen representative strains were selected and tested using a dynamic bladder infection model. Oral ciprofloxacin dosing was simulated over 3 days (250 mg daily, 500 mg daily, 250 mg 12 hourly, 500 mg 12 hourly and 750 mg 12 hourly). The model was run for 96 h. Primary endpoint was change in bacterial density at 72 h. Secondary endpoints were follow-up change in bacterial density at 96 h and area-under-bacterial-kill-curve. Bacterial response was related to exposure (AUC0-24/MIC; Cmax/MIC). PTA was determined using Monte-Carlo simulation.

RESULTS

Ninety-three clinical isolates demonstrated a trimodal ciprofloxacin MIC distribution (modal MICs at 0.016, 0.25 and 32 mg/L). Fifteen selected clinical isolates (ciprofloxacin MIC 0.25-512 mg/L) had a broad range of quinolone-resistance genes. Following ciprofloxacin exposure, E. coli ATCC 25922 (MIC 0.008 mg/L) was killed in all dosing experiments. Six isolates (MIC ≥ 16 mg/L) regrew in all experiments. Remaining isolates (MIC 0.25-8 mg/L) regrew variably after an initial period of killing, depending on simulated ciprofloxacin dose. A >95% PTA, using AUC0-24/MIC targets, supported 250 mg 12 hourly for susceptible isolates (MIC ≤ 0.25 mg/L). For isolates with MIC ≤ 1 mg/L, 750 mg 12 hourly promoted 3 log10 kill at the end of treatment (72 h), 1 log10 kill at follow-up (96 h) and 90% maximal activity (AUBKC0-96).

CONCLUSIONS

Bladder infection modelling supports oral ciprofloxacin activity against E. coli with low-level resistance (ciprofloxacin MIC ≤ 1 mg/L) when using high dose therapy (750 mg 12 hourly).

Acquisition of genomic elements were pivotal for the success of Escherichia coli ST410

BACKGROUND

Escherichia coli ST410 is an emerging MDR clone linked to blaCTX-M-15 and blaOXA-181. Limited comprehensive data about the global distribution of ST410 clades and mobile genetic elements associated with different β-lactamases are available.

METHODS

Short- and long-read WGS were performed on a collection of ST410 producing carbapenemases (n = 45) obtained from 11 countries. The evolutionary history of global E. coli ST410 was also investigated.

RESULTS

OXA-181 and NDM-5 were the most frequent carbapenemases and used different underlying strategies to ensure their successful association with ST410 clades. Our phylogenetic analysis of publicly available ST410 genomes amended the previously published ST410 B subclades: ST410-B1 is identical to B1/H24, ST410-B2 includes B2/H24R and B3/H24Rx, while ST410-B3 corresponds to B4/H24RxC. Long-read WGS identified the following genomic events that likely shaped the evolution of ST410-B3: (i) gyrA and parC mutations were acquired via homologous recombination events; (ii) chromosomal integration of blaCMY-2 among ST410-B3; (iii) the emergence of ST410-B3 from ST410-B2 was accompanied by the replacement of IncFII plasmids harbouring blaCTX-M-15 (i.e. F36:31:A4:B1 in ST410-B2 with F1:A1:B49 plasmids in ST410-B3); and (iv) the NDM-5 gene was integrated within F1:A1:B49 plasmids over time.

CONCLUSIONS

The global ST410 population producing carbapenemases is dominated by the ST410-B2 and B3 subclades with varied geographical distribution that requires ongoing genomic surveillance. We provided an updated timeline of pivotal genomic events that have shaped the success of the ST410-B3 subclade.

Non-lactose fermenting Escherichia coli: Following in the footsteps of lactose fermenting E. coli high-risk clones

Multi-resistant pathogenic strains of non-lactose fermenting Escherichia coli (NLF E. coli) are responsible for various intestinal and extraintestinal infections. Although several studies have characterised such strains using conventional methods, they have not been comprehensively studied at the genomic level. To address this gap, we used whole-genome sequencing (WGS) coupled with detailed microbiological and biochemical testing to investigate 17 NLF E. coli from a diagnostic centre (icddr,b) in Dhaka, Bangladesh. The prevalence of NLF E. coli was 10%, of which 47% (8/17) exhibited multi-drug resistant (MDR) phenotypes. All isolates (17/17) were confirmed as E. coli and could not ferment lactose sugar. WGS data analysis revealed international high-risk clonal lineages. The most prevalent sequence types (STs) were ST131 (23%), ST1193 (18%), ST12 (18%), ST501 (12%), ST167 (6%), ST73 (6%) and ST12 (6%). Phylogenetic analysis corroborated a striking clonal population amongst the studied NLF E. coli isolates. The predominant phylogroup detected was B2 (65%). The bla CTX-M-15 extended-spectrum beta-lactamase gene was present in 53% of isolates (9/17), whilst 64.7% (11/17) isolates were affiliated with pathogenic pathotypes. All extraintestinal pathogenic E. coli pathotypes demonstrated β-hemolysis. Our study underscores the presence of critical pathogens and MDR clones amongst non-lactose fermenting E. coli. We suggest that non-lactose fermenting E. coli be considered equally capable as lactose fermenting forms in causing intestinal and extraintestinal infections. Further, there is a need to undertake systematic, unbiased monitoring of predominant lineages amongst non-lactose fermenting E. coli that would help in better treatment and prevention strategies.

Longitudinal Study on Extended-Spectrum Beta-Lactamase-E. coli in Sentinel Mallard Ducks in an Important Baltic Stop-Over Site for Migratory Ducks in Germany

Antimicrobial resistance (AMR) is a serious global health threat with extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales as the most critical ones. Studies on AMR in wild birds imply a possible dissemination function and indicate their potential role as sentinel animals. This study aimed to gain a deeper insight into the AMR burden of wild waterfowl by sampling semi-wild mallard ducks used as sentinels and to identify if AMR bacteria could be recommended to be added to the pathogens of public health risks to be screened for. In total, 376 cloacal and pooled fecal samples were collected from the sentinel plant over a period of two years. Samples were screened for ESBL-carrying E. coli and isolates found further analyzed using antimicrobial susceptibility testing and whole-genome sequencing. Over the sampling period, 4.26% (16/376) of the samples were positive for ESBL-producing E. coli. BlaCTX-M-1 and blaCTX-M-32 were the most abundant CTX-M types. Although none of the top global sequence types (ST) could be detected, poultry-derived ST115 and non-poultry-related STs were found and could be followed over time. The current study revealed low cases of ESBL-producing E. coli in semi-wild mallard ducks, which proves the suitability of sentinel surveillance for AMR detection in water-associated wildlife.

Prevalence of Escherichia coli ST1193 Causing Intracranial Infection in Changsha, China

ST1193 is an emerging new virulent and resistant clone among Escherichia coli with a tendency to spread rapidly across the globe. However, the prevalence of intracranial infection-causing E. coli ST1193 is rarely reported. This study aimed at determining the prevalence of E. coli ST1193 isolates, causing intracranial infections in Changsha, central China. A total of 28 E. coli isolates were collected from the cerebrospinal fluid of patients with intracranial infection over a four-year period. All isolates were differentiated using multilocus sequence typing (MLST), and phylogenetic grouping, and tested for antibiotic resistance. MLST analysis showed 11 sequence types (ST) among the 28 E. coli isolates. The most prevalent ST was B2-ST1193 (28.6%, 8/28), followed by B2-ST131 (21.4%, 6/28) and F-ST648 (10.7%, 3/28). Of the eight ST1193 isolates, three carried CTX-M-55, and one carried CTX-M-27. All eight ST1193 isolates were resistant to Ciprofloxacin, showing gyrA1AB/parC4A mutations. Two ST1193 isolates carried the aac(6′)-Ib-cr gene. All ST1193 isolates were recovered from infants with meningitis, with a fatal outcome for one three-month-old infant. ST1193 has emerged as the predominant type of E. coli strain causing intracranial infections in Changsha, China. This study highlights the importance of implementing appropriate surveillance measures to prevent the spread of this emerging public health threat.