Long-term gut colonization with ESBL-producing Escherichia coli in participants without known risk factors from the southeastern United States

We evaluated gut carriage of extended spectrum beta lactamase producing Enterobacteriaceae (ESBL-E) in southeastern U.S. residents without recent in-patient healthcare exposure. Study enrollment was January 2021-February 2022 in Athens, Georgia, U.S. and included a diverse population of 505 adults plus 50 child participants (age 0-5). Based on culture-based screening of stool samples, 4.5% of 555 participants carried ESBL-Es. This is slightly higher than reported in studies conducted 2012-2015, which found carriage rates of 2.5-3.9% in healthy U.S. residents. All ESBL-E confirmed isolates (n=25) were identified as Escherichia coli. Isolates belonged to 11 sequence types, with 48% classified as ST131. Ninety six percent of ESBL-E isolates carried a blaCTX-M gene. Isolated ESBL-Es frequently carried virulence genes as well as multiple classes of antibiotic resistance genes. Long-term colonization was common, with 64% of ESBL-E positive participants testing positive when rescreened three months later. One participant yielded isolates belonging to two different E. coli sequence types that carried blaCTX-M-1 genes on near-identical plasmids, suggesting intra-gut plasmid transfer. Isolation of E. coli on media without antibiotics revealed that ESBL-E. coli typically made up a minor fraction of the overall gut E. coli population, although in some cases they were the dominant strain. ESBL-E carriage was not associated with a significantly different stool microbiome composition. However, some microbial taxa were differentially abundant in ESBL-E carriers. Together, these results suggest that a small subpopulation of US residents are long-term, asymptomatic carriers of ESBL-Es, and may serve as an important reservoir for community spread of these ESBL genes.

A nested cohort 5-year Canadian surveillance of Gram-negative antimicrobial resistance for optimized antimicrobial therapy

We analyzed 5 years (2016-2020) of nested Canadian data from the Study for Monitoring Antimicrobial Resistance Trends (SMART) to identify pathogen predominance and antimicrobial resistance (AMR) patterns of adult Gram-negative infections in Canadian health care and to complement other public surveillance programs and studies in Canada. A total of 6853 isolates were analyzed from medical (44%), surgical (18%), intensive care (22%) and emergency units (15%) and from respiratory tract (36%), intra-abdominal (25%), urinary tract (24%) and bloodstream (15%) infections. Overall, E. coli (36%), P. aeruginosa (18%) and K. pneumoniae (12%) were the most frequent isolates and P. aeruginosa was the most common respiratory pathogen. 18% of Enterobacterales species were ESBL positive. Collective susceptibility profiles showed that P. aeruginosa isolates were highly susceptible (> 95%) to ceftolozane/tazobactam and colistin, though markedly less susceptible (58-74%) to other antimicrobials tested. Multi-drug resistance (MDR) was present in 10% of P. aeruginosa isolates and was more frequent in those from respiratory infections and from ICU than non-ICU locations. Of P. aeruginosa isolates that were resistant to combinations of ceftazidime, piperacillin/tazobactam and meropenem, 73-96% were susceptible to ceftolozane/tazobactam over the period of the study. These national data can now be combined with clinical prediction rules and genomic data to enable expert antimicrobial stewardship applications and guide treatment policies to optimize adult patient care.

Community carriage of ESBL-producing Escherichia coli and Klebsiella pneumoniae: a cross-sectional study of risk factors and comparative genomics of carriage and clinical isolates

The global prevalence of infections caused by extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) is increasing, and for Escherichia coli, observations indicate that this is partly driven by community-onset cases. The ESBL-E population structure in the community is scarcely described, and data on risk factors for carriage are conflicting. Here, we report the prevalence and population structure of fecal ESBL-producing E. coli and Klebsiella pneumoniae (ESBL-Ec/Kp) in a general adult population, examine risk factors, and compare carriage isolates with contemporary clinical isolates. Fecal samples obtained from 4,999 participants (54% women) ≥40 years in the seventh survey of the population-based Tromsø Study, Norway (2015, 2016), were screened for ESBL-Ec/Kp. In addition, we included 118 ESBL-Ec clinical isolates from the Norwegian surveillance program in 2014. All isolates were whole-genome sequenced. Risk factors associated with carriage were analyzed using multivariable logistic regression. ESBL-Ec gastrointestinal carriage prevalence was 3.3% [95% confidence interval (CI) 2.8%-3.9%, no sex difference] and 0.08% (0.02%-0.20%) for ESBL-Kp. For ESBL-Ec, travel to Asia was the only independent risk factor (adjusted odds ratio 3.46, 95% CI 2.18-5.49). E. coli ST131 was most prevalent in both collections. However, the ST131 proportion was significantly lower in carriage (24%) versus clinical isolates (58%, P < 0.001). Carriage isolates were genetically more diverse with a higher proportion of phylogroup A (26%) than clinical isolates (5%, P < 0.001), indicating that ESBL gene acquisition occurs in a variety of E. coli lineages colonizing the gut. STs commonly related to extraintestinal infections were more frequent in clinical isolates also carrying a higher prevalence of antimicrobial resistance, which could indicate clone-associated pathogenicity.IMPORTANCEESBL-Ec and ESBL-Kp are major pathogens in the global burden of antimicrobial resistance. However, there is a gap in knowledge concerning the bacterial population structure of human ESBL-Ec/Kp carriage isolates in the community. We have examined ESBL-Ec/Kp isolates from a population-based study and compared these to contemporary clinical isolates. The large genetic diversity of carriage isolates indicates frequent ESBL gene acquisition, while those causing invasive infections are more clone dependent and associated with a higher prevalence of antibiotic resistance. The knowledge of factors associated with ESBL carriage helps to identify patients at risk to combat the spread of resistant bacteria within the healthcare system. Particularly, previous travel to Asia stands out as a major risk factor for carriage and should be considered in selecting empirical antibiotic treatment in critically ill patients.

Carriage of multidrug-resistant Gram-negative bacilli: duration and risk factors

Identification of risk factors influencing the duration of carriage of multidrug-resistant Gram-negative bacilli (MDR-GNB) may be useful for infection control. The aim of this study is to estimate the impact of several factors collected for routine hospital surveillance on the duration of carriage of selected MDR-GNB. From January 2015 to July 2021, patients with at least two clinical/surveillance samples positive for MDR-GNB different from ESBL-producing E. coli or AmpC - exclusively producing Enterobacterales were assessed. Microorganisms, age, number of admissions, clinical or rectal sample, sex, and admission service were evaluated as risk factors. Multivariate analysis was performed by a Cox proportional hazard model. A total of 1981 episodes of colonization were included. Involved microorganisms were ESBL-Klebsiella pneumoniae (KP) in 1057 cases (53.4%), other ESBL-non-E. coli Enterobacterales in 91 (4.6%), OXA-48-KP in 263 (13.3%), KPC-KP in 90 (4.5%), VIM-KP in 29 (1.5%), carbapenemase-producing non-KP Enterobacterales (CP-non-KP) in 124 (6.3%), and MDR Pseudomonas aeruginosa (MDR-PAER) in 327 (16.5%). No differences in duration of colonization were observed among ESBL-KP (median colonization time 320 days), ESBL-non-E. coli Enterobacterales (226 days), OXA48-KP (305 days), and MDR-PAER (321 days). For each group, duration of colonization was significantly longer than that of KPC-KP (median colonization time 60 days), VIM-KP (138 days), and CP-non-KP (71 days). Male sex (HR = 0.88; 95% CI 0.78-0.99), detection in Hepatology-Gastroenterology (HR = 0.71; 95% CI 0.54-0.93), clinical sample (HR = 0.61; 95% CI 0.53-0.69), and > 2 admissions after first detection (HR = 0.47; 95% CI 0.42-0.52) were independent predictors of longer carriage, whereas VIM-KP (HR = 1.61; 95% CI 1.04-2.48), KPC-KP (HR = 1.85; 95% CI 1.49-2.3), and CP-non-KP (HR = 1.92; 95% CI 1.49-2.47) were associated with shorter colonization time. Duration of colonization was significantly longer for ESBL-KP, other ESBL-non-E. coli Enterobacterales, OXA-48-KP, and MDR-PAER. For these microorganisms, prolonging surveillance up to 2.5-3 years should be considered. Male sex, clinical sample, multiple readmissions, admission service, and type of microorganism are independent predictors of the duration of carriage.

Intestinal colonization with multidrug-resistant Enterobacterales: screening, epidemiology, clinical impact, and strategies to decolonize carriers

The clinical impact of infections due to extended-spectrum β-lactamase (ESBL)- and/or carbapenemase-producing Enterobacterales (Ent) has reached dramatic levels worldwide. Infections due to these multidrug-resistant (MDR) pathogens-especially Escherichia coli and Klebsiella pneumoniae-may originate from a prior asymptomatic intestinal colonization that could also favor transmission to other subjects. It is therefore desirable that gut carriers are rapidly identified to try preventing both the occurrence of serious endogenous infections and potential transmission. Together with the infection prevention and control countermeasures, any strategy capable of effectively eradicating the MDR-Ent from the intestinal tract would be desirable. In this narrative review, we present a summary of the different aspects linked to the intestinal colonization due to MDR-Ent. In particular, culture- and molecular-based screening techniques to identify carriers, data on prevalence and risk factors in different populations, clinical impact, length of colonization, and contribution to transmission in various settings will be overviewed. We will also discuss the standard strategies (selective digestive decontamination, fecal microbiota transplant) and those still in development (bacteriophages, probiotics, microcins, and CRISPR-Cas-based) that might be used to decolonize MDR-Ent carriers.

High level of colonization with 3rd-generation cephalosporin-resistant Enterobacterales in African community settings, Ghana

A cross-sectional survey was conducted in eight Ghanaian communities to investigate the extent of intestinal colonization with 3^rd-generation cephalosporin-resistant Enterobacterales. The study collected faecal samples and corresponding lifestyle data from 736 healthy residents to assess the occurrence of cephalosporin-resistant Escherichia coli and Klebsiella pneumoniae, with a focus on genotypes of plasmid-mediated ESBLs, AmpCs, and carbapenemases. The results showed that 371 participants (50.4%) carried 3^rd-generation cephalosporin-resistant E. coli (n=362) and K. pneumoniae (n=9). Most of these were ESBL-producing E. coli (n=352, 94.9%), carrying CTX-M genes (96.0%, n=338/352), mostly for CTX-M-15 (98.9%, n=334/338). Nine participants (1.2%) carried AmpC-producing E. coli that harboured bla_DHA-1 or blaCMY-2 genes, and two participants (0.3%) each carried a carbapenem-resistant E. coli that harboured both bla_NDM-1 and bla_CMY-2. Quinolone-resistant O25b: ST131 E. coli were recovered from six participants (0.8%) and were all CTX-M-15 ESBL-producers. Having a household toilet facility was significantly associated with a reduced risk of intestinal colonization (adjusted odds ratio, 0.71; 95% CI, 0.48-0.99; P-value=0.0095) in multivariate analysis. These findings raise serious public health concerns, and effective control of the spread of antibiotic-resistant bacteria is possible by providing better sanitary conditions for communities.

Prevalence of Antimicrobial Resistance and Infectious Diseases in a Hospitalised Migrant Population in Paris, France, a Retrospective Study

Objectives: The aim of this study was to estimate the prevalence of anti-microbial resistance (AMR) carriage and its risk factors in hospitalized migrants. Additionally, the prevalence of infectious diseases was evaluated, as well as symptoms of psychological trauma. Methods: We conducted a retrospective monocentric cross-sectional study including all migrant patients recently arrived and hospitalised over a one-year period. Results: Among 101 patients, seventy-nine percent originated from Sub-Saharan Africa. The overall AMR carriage rate was 20.7% [95% CI: 12.4; 28.9%]. We isolated 5/92 methicillin-resistant Staphylococcus aureus strains (5.4%) and 15/92 extended-spectrum beta-lactamase-producing Enterobacteriaceae (16.4%). AMR carriage was associated with older age, region of origin and length of migration. Rates of HIV, HBV, and HCV infection were 39.6%, 32.7%, and 5%, reflecting sampling bias linked to reasons for hospitalization. Eleven percent had serological evidence of treponemasis and 7.8% had Chlamydia trachomatis infection. Symptoms of depression or post-traumatic stress disorder were observed for more than half the patients. Conclusion: It appears essential to offer a systematic and comprehensive post-arrival screening of AMR carriage, infectious diseases and psychological trauma to subjects who experienced migration.

Faecal carriage of multidrug-resistant bacteria and associated risk factors: results from a point prevalence study

OBJECTIVES

Since 2003, incidences of carbapenemase-producing Gram-negative bacilli (CP-GNB) and vancomycin-resistant Enterococcus faecium (VRE) have steadily increased in France. We therefore conducted a point prevalence study to estimate carriage rates of CP-GNB, VRE and ESBL-producing Enterobacterales (ESBL-PE) and associated risk factors.

METHODS

Between September 2019 and January 2020, all inpatients hospitalized on a given day in 11 teaching hospitals in the Paris urban area were eligible. Patient interviews and rectal swab screening results were recorded by dedicated nurses. The swabs were plated onto selective chromogenic media and processed using the GeneXpert® system.

RESULTS

Of 2396 patients, 364 (15.2%) yielded at least one multiresistant bacterial isolate, including 29 CP-GNB carriers (1.2%), 13 VRE carriers (0.5%) and 338 ESBL-PE carriers (14%). In 15 patients (4.4% of ESBL-PE carriers and 36.6% of CP-GNB/VRE carriers), concomitant CP-GNB/VRE and ESBL-PE carriage was observed. In 7/29 CP-GNB and 7/13 VRE carriers, carbapenemase production and vanA in the screening samples was only detected with Xpert® tests. The OXA-48 gene was predominant in 13/34 CP-GNB isolates from 29 carriers. From the 338 ESBL-PE carriers, 372 isolates were recovered, mainly Escherichia coli (61.2%). Among 379 children, 1.1% carried a CP-GNB/VRE strain, and 12.4% carried an ESBL strain. Previous hospitalization outside mainland France, previous antimicrobial treatment and previous ESBL-PE carriage were the main risk factors associated with CP-GNB and/or VRE carriage.

CONCLUSIONS

The low CP-GNB and VRE prevalence likely reflects the French policy to limit intrahospital spread of CP-GNB and VRE strains.

Prevalence and household risk factors for fecal carriage of ESBL-producing, sequence type 131, and extraintestinal pathogenic Escherichia coli among children in southern Taiwan

BACKGROUND

The rapidly increasing prevalence of antimicrobial-resistant Escherichia coli (E. coli) is a global concern. This study determined the prevalence and risk factors for the fecal carriage of drug-resistant E. coli and extraintestinal pathogenic E. coli (ExPEC) among children.

MATERIALS AND METHODS

In this prospective study, stool samples from children aged 0-18 years were obtained within three days of hospitalization between April 2016 and March 2019. E. coli were selected and tested for extended-spectrum β-lactamase (ESBL)-production and antimicrobial susceptibility. Multilocus sequence typing, blaCTX-M gene groups and ExPEC were determined using polymerase chain reactions. Questionnaires were recorded for risk factor analysis.

RESULTS

Among 179 E. coli isolates, 44.1% were multi-drug resistant, 20.7% produced ESBL, and 50.3% were ExPEC. Children carrying ESBL-producing E. coli were younger than those carrying non-ESBL strains. Several anthropogenic factors, including drinking water process, pork consumption, pets and household density might be associated with ESBL-producing E. coli, sequence type (ST) 131 E. coli, or ExPEC fecal carriage. Compared with families who live in less crowded houses, participants with pets had a similar trend of higher risks of ESBL-producing E. coli, ST131 E. coli, and ExPEC fecal carriage among those living in houses accommodating relatively more people.

CONCLUSIONS

Children accounted for a large proportion of instances of feces carrying ESBL E. coli. In addition to antimicrobial control for people and livestocks, avenues of exposure, such as drinking water, food, pets, household density, and socioeconomic deprivation might present potentially novel opportunities to reduce the burden of nonsusceptible E. coli and ExPEC.

Extended Spectrum β-Lactamase Producing Lactose Fermenting Bacteria Colonizing Children with Human Immunodeficiency Virus, Sickle Cell Disease and Diabetes Mellitus in Mwanza City, Tanzania: A Cross-Sectional Study

Rectal carriage of extended spectrum β-lactamase-lactose fermenters (ESBL-LF) is the major risk factor for the development of subsequent endogenous infections. This study determined the patterns and factors associated with the rectal carriage of ESBL-LF among children with Human Immunodeficiency Virus (HIV), Diabetes Mellitus (DM), and Sickle Cell Disease (SCD) attending clinics at different health care facilities in the city of Mwanza, Tanzania. A cross-sectional study was conducted among children living with HIV (n = 236), DM (n = 42) and SCD (n = 126) between July and September 2021. Socio-demographic and clinical data were collected using a structured questionnaire. Rectal swabs/stool samples were collected and processed to detect the rectal carriage of ESBL-LF following laboratory standard operating procedures (SOPs). Descriptive statistical analysis was conducted using STATA 13.0. The overall prevalence of ESBL-LF carriage was 94/404 (23.3%). Significantly higher resistance was observed to ampicillin, trimethoprim-sulfamethoxazole, and tetracycline among Enterobacteriaceae isolated from HIV infected children than in non-HIV infected children (p < 0.05). The commonest ESBL allele 45/62 (72.6%) detected was blaCTX-M. Generally, a parent’s low education level was found to be associated with ESBL-LF colonization among children living with HIV; (OR 4.60 [95%CI] [1.04−20], p = 0.044). A higher proportion of ESBL-LF from DM 10/10 (100%) carried ESBL genes than ESBL-LF from HIV 37/56 (66.1%) and SCD 15/28 (53.6%), p = 0.02. There is a need to collect more data regarding trimethoprim-sulfamethoxazole (SXT) prophylaxis and antibiotic resistance to guide the decision of providing SXT prophylaxis in HIV-infected children especially at this time, when testing and treatment is carried out.

Spread of the blaOXA-48/IncL Plasmid within and between Dogs in City Parks, France

The bla_OXA-48/IncL plasmid is increasingly reported in dogs, even in the absence of carbapenem use in animals. In this study, we witnessed the spread of this plasmid within and between dogs sharing the same relaxing area. This indicates a very dynamic situation where carbapenem resistance can be transmitted between dogs and expanded in the dogs’ gut. As a consequence, picking up dog feces may lower both this dynamic and the global antimicrobial resistance burden.

IMPORTANCE The use of carbapenems in animals is forbidden in France due to their critical importance to treat human diseases. Nevertheless, bla_OXA-48-producing Enterobacterales were sporadically recovered in cats and dogs, most likely as a spill over from the human reservoir. This study highlights the rapid spread of bla_OXA-48 once transmitted to dogs, suggesting that companion animals can play a role in the transmission routes of carbapenemase genes.

Rectal colonization by resistant bacteria increases the risk of infection by the colonizing strain in critically ill patients with cirrhosis

BACKGROUND & AIMS

It remains unclear whether rectal colonization with multidrug-resistant organisms (MDROs) is prevalent and predisposes to infections by the same pathogens in patients with cirrhosis.

METHODS

Two series of critically ill patients were evaluated. In the Barcelona cohort, 486 consecutive patients were prospectively evaluated, 129 with and 357 without cirrhosis (2015-2016). Rectal swabs were performed at admission and weekly thereafter (until intensive care unit [ICU] discharge) to detect MDRO colonization. Risk factors for colonization and infection by MDROs were evaluated. A retrospective cohort from Frankfurt (421 patients with cirrhosis; 2010-2018) was investigated to evaluate MDRO rectal colonization in another epidemiological scenario.

RESULTS

In the Barcelona cohort, 159 patients were colonized by MDROs (32.7%), 102 (64.2%) at admission and 57 (35.8%) during follow-up. Patients with cirrhosis showed higher rates of rectal colonization at admission than those without cirrhosis (28.7% vs. 18.2%, p = 0.01) but similar colonization rates during ICU stay. Extended-spectrum beta-lactamase-Enterobacterales were the most frequent MDROs isolated in both groups. Colonization by MDROs independently increased the risk of infection by MDROs at admission and during follow-up. Risk of new infection by the colonizing strain was also significantly increased in patients with (hazard ratio [HR] 7.41) and without (HR 5.65) cirrhosis. Rectal colonization by MDROs was also highly prevalent in Frankfurt (n = 198; 47%; 131 at admission [66.2%] and 67 [33.8%] during follow-up), with vancomycin-resistant enterococci being the most frequent colonizing organism. Rectal colonization by MDROs was also associated with an increased risk of infection by MDROs in this cohort. Infections occurring in MDR carriers were mainly caused by the colonizing strain.

CONCLUSION

Rectal colonization by MDROs is extremely frequent in critically ill patients with cirrhosis. Colonization increases the risk of infection by the colonizing resistant strain.

LAY SUMMARY

Rectal colonization by multidrug-resistant organisms (MDROs) is a prevalent problem in patients with cirrhosis requiring critical care. The pattern of colonizing bacteria is heterogeneous with relevant differences between centers. Colonization by MDROs is associated with increased risk of infection by the colonizing bacteria in the short term. This finding suggests that colonization data could be used to guide empirical antibiotic therapy and de-escalation policies in patients with cirrhosis.

Urban Wildlife Crisis: Australian Silver Gull Is a Bystander Host to Widespread Clinical Antibiotic Resistance

The Australian silver gull is an urban-adapted species that frequents anthropogenic waste sites. The enterobacterial flora of synanthropic birds often carries antibiotic resistance genes. Whole-genome sequence analyses of 425 Escherichia coli isolates from cloacal swabs of chicks inhabiting three coastal sites in New South Wales, Australia, cultured on media supplemented with meropenem, cefotaxime, or ciprofloxacin are reported. Phylogenetically, over 170 antibiotic-resistant lineages from 96 sequence types (STs) representing all major phylogroups were identified. Remarkably, 25 STs hosted the carbapenemase gene bla_IMP-4, sourced only from Five Islands. Class 1 integrons carrying bla_IMP and bla_OXA alongside bla_CTX-M and qnrS were notable. Multiple plasmid types mobilized bla_IMP-4 and bla_OXA-1, and 121 isolates (28%) carried either a ColV-like (18%) or a pUTI89-like (10%) F virulence plasmid. Phylogenetic comparisons to human isolates provided evidence of interspecies transmission. Our study underscores the importance of bystander species in the transmission of antibiotic-resistant and pathogenic E. coli. IMPORTANCE By compiling various genomic and phenotypic data sets, we have provided one of the most comprehensive genomic studies of Escherichia coli isolates from the Australian silver gull, on media containing clinically relevant antibiotics. The analysis of genetic structures capturing antimicrobial resistance genes across three gull breeding colonies in New South Wales, Australia, and comparisons to clinical data have revealed a range of trackable genetic signatures that highlight the broad distribution of clinical antimicrobial resistance in more than 170 different lineages of E. coli. Conserved truncation sizes of the class 1 integrase gene, a key component of multiple-drug resistance structures in the Enterobacteriaceae, represent unique deletion events that are helping to link seemingly disparate isolates and highlight epidemiologically relevant data between wildlife and clinical sources. Notably, only the most anthropogenically affected of the three sites (Five Islands) was observed to host carbapenem resistance, indicating a potential reservoir among the sites sampled.

Evidence of sexual transmission of extended-spectrum β-lactamase-producing Enterobacterales: a cross-sectional and prospective study

BACKGROUND

Extended spectrum β-lactamase-producing Enterobacterales (ESBL-E) represent a major threat to public health. Little is known on their potential for sexual transmission.

METHODS

We recruited individuals at a sexually transmitted infection and HIV-outpatient clinic in Paris, France in whom we evaluated the prevalence of ESBL-E intestinal carriage and among those positive, the proportion with clearance 6 months thereafter. We compared carriage prevalence between groups using logistic regression adjusted for age, geographic origin, travel outside of Europe, and antibiotic use <6 months.

RESULTS

2157 individuals participated, of whom 226 (10.5%) were ESBL-E carriers. The proportion of ESBL-E carriers varied across sexual groups: HIV-negative men who have sex with men (MSM) on pre-exposure prophylaxis (PrEP), 16.3% (n=41/251); HIV-negative MSM not on PrEP, 9.7% (n=47/487); HIV-positive MSM, 12.2% (n=61/500); HIV-negative men who exclusively have sex with women, 10.0% (n=44/439); and HIV-negative women who have sex with men (WSM), 6.9% (n=33/480). After adjustment, ESBL-E prevalence was significantly higher in HIV-negative MSM on PrEP (p<0.001) and HIV-positive MSM (p=0.01) compared to WSM. Number of sexual partners <6 months was associated with ESBL-E carriage after adjustment (p=0.004). blaSHV-12-producing ESBL-E and E. coli Sequence Type 14 were observed only in MSM. Of 102 individuals with ESBL-E returning for testing, 26 (25%) had carriage at 6 months.

CONCLUSION

ESBL-E carriage is more frequent in MSM undergoing PrEP or living with HIV, and with increasing number of sexual partners. More research is warranted to understand the consequences of ESBL-E carriage in these populations and how transmission can be reduced.

From Pathophysiological Hypotheses to Case–Control Study Design: Resistance from Antibiotic Exposure in Community-Onset Infections

Antimicrobial resistance is a global public health concern, at least partly due to the misuse of antibiotics. The increasing prevalence of antibiotic-resistant infections in the community has shifted at-risk populations into the general population. Numerous case–control studies attempt to better understand the link between antibiotic use and antibiotic-resistant community-onset infections. We review the designs of such studies, focusing on community-onset bloodstream and urinary tract infections. We highlight their methodological heterogeneity in the key points related to the antibiotic exposure, the population and design. We show the impact of this heterogeneity on study results, through the example of extended-spectrum β-lactamases producing Enterobacteriaceae. Finally, we emphasize the need for the greater standardization of such studies and discuss how the definition of a pathophysiological hypothesis specific to the bacteria–resistance pair studied is an important prerequisite to clarify the design of future studies.

Novel insights into pivotal risk factors for rectal carriage of extended-spectrum-β-lactamase-producing enterobacterales within the general population in Lower Saxony, Germany

AIMS

To estimate the prevalence of extended-spectrum-β-lactamase (ESBL)-producing enterobacterales (ESBL-E) carriage in the general population of Lower Saxony, Germany, and to identify risk factors for being colonized.

METHODS AND RESULTS

Participants were recruited through local press and information events. Detection of ESBL-E by culture was conducted using ESBL-selective chromagar plates containing third-generation cephalosporins. Identification of pathogens was performed using matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF)_technology on Vitek mass spectrometry. Antibiotic susceptibility testing was conducted by microdilution (Vitek II) and an ESBL confirmation assay was carried out using a combination disk test. Of 527 randomly collected stool samples from healthy volunteers, 5.5% were tested positive for ESBL-E. Post-stratification for age and gender yielded a similar population estimate (5.9%). People traveling abroad and taking antibiotics had the greatest rectal ESBL-E carriage.

CONCLUSIONS

Potential risk factors (eg, working in healthcare facilities, recent inpatient stay) did not attribute to rectal ESBL-E carriage as other factors (eg, travelling, taking antibiotics). Rectal ESBL-E carriage within the general population seems to be high.

SIGNIFICANCE AND IMPACT OF THE STUDY

The known risk factors for carriage with MDRO might not be fully applicable to ESBL-E and require further examination in order to develop effective strategies for the prevention of ESBL-E dissemination within the general population.

Carriage of Multidrug-Resistant Bacteria in Healthy People: Recognition of Several Risk Groups

The increase in multidrug-resistant (MDR) bacteria in hospitalized people and the hospital environment has been thoroughly documented. In contrast, little is known about their presence in the community. However, increasing evidence is showing a high level of carriage in people without infectious signs. Colonized people can later develop infections due to MDR bacteria and may be able to transmit them to susceptible people (the number of which is increasing worldwide), for example, people with comorbidities such as diabetes, cancer, or inflammatory diseases and those in extreme age groups. Risk factors for the acquisition of MDR bacteria are as follows: (1) residence or travel in countries with high levels of MDR bacteria; (2) occupational risks such as health workers or people with close contact with animals (farmers, veterinarians) who frequently use antibiotics; and (3) comorbidities. Eradication is rather difficult and, thus far, has not shown clear-cut results. Preventive measures will be important in the future with a reinforcement of hygienic measures not only in the hospital, but also in the community.

Spread of ESC-, carbapenem- and colistin-resistant Escherichia coli clones and plasmids within and between food workers in Lebanon

OBJECTIVES

Knowledge on the dynamic of MDR Escherichia coli in the human community is still limited, especially in low- and middle-income countries. Our goal was to decipher the dynamics of E. coli lineages and plasmids resistant to ESC, carbapenem and colistin within and between food workers in Lebanon using genomic-based approaches.

METHODS

Eighty-four healthy adults working in three bakeries were sampled twice at a 6 monthly interval. E. coli resistant to ESC (ESC-E), carbapenem (CP-E) and colistin (CO-E) were collected on selective plates. Non-duplicate isolates were whole-genome sequenced using the Illumina technology and plasmid transmission was assessed by long-read sequencing. Data were analysed using bioinformatics tools and SNP-based phylogeny.

RESULTS

ESC-E carriage rate reached 34.5% (t0) and 52.9% (t6), and 15 workers were positive at both t0 and t6. Carbapenem resistance (blaOXA-181, blaOXA-204, blaNDM-5) was found in five workers at t0 and two at t6, while colistin resistance (mcr-1.1) was found in five workers at t0 and one at t6. Forty-seven different STs were identified, of which three STs were predominant (ST131, n = 9; ST10, n = 5; ST69, n = 5). One worker presented the same ESC-E clone at t0 and t6. Twelve different events of clonal transmission among individuals were exemplified while plasmid transmission was only shown once.

CONCLUSIONS

Our study revealed a high carriage rate of MDR E. coli (60.7%) and the emergence of CP and colistin resistance in the Lebanese community. Incidental and long-term ESC-E carriage was observed in 41.7% and 17.9% of the workers, respectively. The high clonal diversity suggests an important dynamic of acquisition and loss of MDR E. coli and limited plasmid spread.

Dynamics of extended-spectrum beta-lactamase-producing Enterobacterales colonization in long-term carriers following travel abroad

Travel to tropical regions is associated with high risk of acquiring extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) that are typically cleared in less than 3 months following return. The conditions leading to persistent carriage that exceeds 3 months in some travellers require investigation. Whole-genome sequencing (Illumina MiSeq) was performed on the 82 ESBL-E isolates detected upon return and 1, 2, 3, 6 and 12 months later from the stools of 11 long-term (>3 months) ESBL-E carriers following travel abroad. One to five different ESBL Escherichia coli strains were detected per traveller upon return, and this diminished to one after 3 months. Long-term carriage was due to the presence of the same ESBL E. coli strain, for more than 3 months, in 9 out of 11 travellers, belonging to epidemic sequence type complexes (STc 10, 14, 38, 69, 131 and 648). The mean carriage duration of strains belonging to phylogroups B2/D/F, associated with extra-intestinal virulence, was higher than that for commensal-associated A/B1/E phylogroups (3.5 vs 0.5 months, P=0.021). Genes encoding iron capture systems (fyuA, irp), toxins (senB, sat), adhesins (flu, daaF, afa/nfaE, pap, ecpA) and colicin (cjrA) were more often present in persistent strains than in transient ones. Single-nucleotide polymorphism (SNP) analysis in persistent strains showed a maximum divergence of eight SNPs over 12 months without signs of adaptation. Genomic plasticity was observed during the follow-up with the loss or gain of mobile genetic elements such as plasmids, integrons and/or transposons that may contain resistance genes at different points in the follow-up. Long-term colonization of ESBL-E following travel is primarily due to the acquisition of E. coli strains belonging to epidemic clones and harbouring ‘virulence genes’, allowing good adaptation to the intestinal microbiota.

The global prevalence and trend of human intestinal carriage of ESBL-producing Escherichia coli in the community

OBJECTIVES

Intestinal colonization by ESBL Escherichia coli and its association with community-acquired MDR infections is of great concern. This review determined the worldwide prevalence of human faecal ESBL E. coli carriage and its trend in the community over the past two decades.

METHODS

A systematic literature search was conducted using PubMed, EMBASE and Google Scholar to retrieve articles published between 1 January 2000 and 13 February 2020 that contained data on the prevalence of faecal carriage of ESBL E. coli among healthy individuals. A cumulative (for the whole period) meta-analysis was used to estimate the global and regional pooled prevalence rates. Articles were grouped into study periods of 3 years, and subgroup meta-analyses were undertaken to examine the global pooled prevalence over time.

RESULTS

Sixty-two articles covering 29 872 healthy persons were included in this meta-analysis. The cumulative (2003-18) global pooled prevalence of ESBL E. coli intestinal carriage in the community was 16.5% (95% CI 14.3%-18.7%; P  <  0.001). The pooled prevalence showed an upward trend, increasing from 2.6% (95% CI 1.6%-4.0%) in 2003-05 to 21.1% (95% CI 15.8%-27.0%) in 2015-18. Over the whole period, the highest carriage rate was observed in South-East Asia (27%; 95% CI 2.9%-51.3%), while the lowest occurred in Europe (6.0%; 95% CI 4.6%-7.5%).

CONCLUSIONS

Globally, an 8-fold increase in the intestinal carriage rate of ESBL E. coli in the community has occurred over the past two decades. Prevention of its spread may require new therapeutic and public health strategies.

Intestinal Carriage of Extended-Spectrum β-Lactamase- (ESBL-) Possessing Escherichia coli and Klebsiella Species among Nepalese Health Science and Non-Health Science Students

Infections due to extended-spectrum β-lactamase- (ESBL-) producing Gram-negative bacteria have led to increased mortality, morbidity, and economic burden worldwide. These bacteria can colonize the healthy intestine of human beings and can disseminate in communities and hospital. This study aimed to investigate the prevalence of fecal carriage of ESBL-producing Escherichia coli and Klebsiella species among health science (HS) and non-health science (NHS) students. This descriptive cross-sectional study was conducted on 104 HS and 104 NHS students in which one stool sample from each student was collected and processed for bacterial culture and sensitivity testing according to standard bacteriological procedures. Each morphotype was identified and characterized phenotypically. The antimicrobial sensitivity profile of bacterial isolates was determined by the Kirby–Bauer disk diffusion technique. ESBL production was tested by combination disk method as recommended by the Clinical and Laboratory Standards Institute. Out of 208 stool samples, E. coli and Klebsiella spp. were recovered from 203 (86.8%) and 31 (13.2%) stool samples, respectively. Among those 234 isolates, 69 were positive for ESBL which included E. coli (n = 66, 95.7%) and Klebsiella spp. (n = 3, 4.3%). Fifty (42.4%) out of 118 isolates from HS students and 19 (16.4%) out of 116 from NHS students were colonized by ESBL-producers. Compared to non-ESBL producers, a higher number of ESBL-producing isolates were resistant to ciprofloxacin (14.5% vs. 1.8%, p < 0.001), cotrimoxazole (59.4% vs. 16.4%, p < 0.001), and amikacin (10.1% vs 4.2%, p < 0.001). All E. coli and Klebsiella species isolates were susceptible to meropenem. The prevalence of fecal carriage of ESBL-producing bacteria was higher in HS students; however, there was a considerable number of these strains colonizing NHS students as well. This “iceberg phenomenon” of asymptomatic carriage of ESBL-producing pathogens might act as a source of infection in both the community and hospitals. Therefore, surveillance of carriage of drug-resistant bacteria should be performed regularly.

Abundance of extended-spectrum β-lactamase genes among intestinal Escherichia coli strains from drug users

Drug users may represent a hidden reservoir of antibiotic resistance genes among their intestinal flora due to the poor hygiene and inappropriate use of antibiotics. Therefore, this study was focused to examine the prevalence of extended-spectrum β-lactamase (ESBL) genes among intestinal Escherichia coli isolated from drug users in Ahvaz, Iran. Among clients of toxicology laboratory who were confirmed their addiction to each of Morphine, Amphetamine or Methamphetamine, 109 drug users were examined voluntarily for infection with hepatitis B or C using commercial enzyme linked immunosorbent assays (ELISA) method. Their stool specimens were obtained to isolate intestinal E. coli. The disc diffusion and combination disk methods were conducted to demonstrate antibiotic resistance pattern and phenotypically ESBL producers. ESBL-encoding genes (bla-TEM, bla-CTX-M, and bla-SHV) were also examined by PCR. Based on results, hepatitis C infection was more prevalent than hepatitis B among drug users. Of 109 isolates, a total of 57 (52.29%) ESBL positive E. coli were obtained from drug users and bla-TEM gene (60.55%) was found to be the most prevalent type, followed by bla-CTX-M (40.36%) and bla-SHV (39.44%). All isolates represented different resistance levels to tested antibiotics and 54.43% of the ESBL‑producing isolates showed multidrug resistance (MDR) and the most frequent MDR pattern was simultaneous resistance to the seven (27.90%) of antimicrobials particularly erythromycin, penicillin, amoxycilin, cefteriaxon, cefotaxim, tetracycline and trimethoprim-Sulfamethoxazole. Fecal carriage of ESBL-production and MDR commensal isolates such as E. coli among drug users underlines the risk of transferring resistance genes between nonpathogenic and pathogenic bacteria.

Multidrug Resistance Dissemination in Escherichia coli Isolated from Wild Animals: Bacterial Clones and Plasmid Complicity

Objectives. Epidemiological data concerning third-generation cephalosporin (3GC) resistance in wild fauna are scarce. The aim of this study was to characterize the resistance genes, their genetic context, and clonal relatedness in 17 Escherichia coli resistant to 3GC isolated from wild animals. Methods. The isolates were characterized by short-read whole genome sequencing, and long-read sequencing was used for the hybrid assembly of plasmid sequences. Results. The 3GC resistance gene most identified in the isolates was the extended-spectrum β-lactamases (ESBL)-encoding gene blaCTX-M-1 (82.3%), followed by blaCTX-M-32 (5.9%), blaCTX-M-14 (5.9%), and blaSHV-12 (5.9%). E. coli isolates mainly belonged to the sequence types (STs) rarely reported from humans. The single nucleotide polymorphism (SNP)-based typing showed that most E. coli genomes from wild animals (wild boars, birds of prey, and buzzards) formed clonal clusters (<5 SNPs), showing a clonal dissemination crossing species boundaries. blaCTX-M-1-harboring IncI1-ST3 plasmid was the predominant ESBL-encoding plasmid (76.4%) in wild animal isolates. Plasmid comparison revealed a 110-kb self-transferable plasmid consisting of a conserved backbone and two variable regions involved in antimicrobial resistance and in interaction with recipient cells during conjugation. Conclusion. Our results highlighted the unexpected clonal dissemination of blaCTX-M-1-encoding clones and the complicity of IncI1-ST3 plasmid in the spread of blaCTX-M-1 within wild fauna.

Stewardship program on carbapenem prescriptions in a tertiary hospital for adults and children in France: a cohort study

Antimicrobial stewardship programs aim at reducing the overuse of broad-spectrum antibiotics such as carbapenems, but their impact remains unclear. We compared the use of carbapenems between paediatric and adult subjects admitted to a French tertiary hospital and described the intervention of an antibiotic stewardship team (AST). As part of AST routine activity, all adult and paediatric patients receiving carbapenems are identified in real time using a computer-generated alert system and reviewed by the AST. Data associated with carbapenem prescriptions were extracted for 2 years (2014-2015) and were compared between paediatric and adult wards. Prescription appropriateness (i.e. no clinically suitable narrower spectrum alternative to carbapenem for de-escalation) and AST intervention were analysed. In total, 775 carbapenem prescriptions for 291 children and 262 adults were included. Most patients (95%) had a comordity and 52% had known recent carriage of extended-spectrum beta-lactamase producing Enterobacteriaceae (ESBLE). Most carbapenem prescriptions came from intensive care units (n = 269, 35%) and were initiated for urinary tract (n = 200, 27%), sepsis (n = 181, 25%), and lung (n = 153, 21%) infections. Carbapenems were initiated empirically in 537 (70%) cases, and an organism was isolated in 523 (67%) cases. Among the isolated organisms, 47% (n = 246) were ESBLE and 90% (n = 468) were susceptible to carbapenems, but an alternative existed in 61% (n = 320) of cases according to antibiotic susceptibility testing. Among prescriptions reviewed by the AST, 39% (n = 255) were considered non-appropriate and led to either antibiotic discontinuation (n = 47, 7%) or de-escalation (n = 208, 32%). Non-appropriate prescriptions were more frequent in paediatric wards (p = 0.01) and in microbiologically documented infections (p = 0.013), and less observed in immunocompromised patients (p = 0.009) or with a known ESBLE carriage (p < 0.001). Tailored stewardship programs are essential to better control carbapenem use and subsequent antimicrobial resistance.

Dissemination of IncF group F1:A2:B20 plasmid-harbouring multidrug-resistant Escherichia coli ST131 before the acquisition of blaCTX-M in Japan

OBJECTIVES

The Escherichia coli O25-ST131 clone is responsible for global dissemination of the bla_CTX-M gene. However, the prevalence of this clone in the digestive tract, devoid of antimicrobial selection, and its molecular epidemiology remain unclear. In this study, we examined the origin of bla_CTX-M-positive E. coli O25-ST131 and its distribution.

METHODS

We separately sequenced the chromosomal and plasmid genomes of 50 E. coli O25 isolates obtained from faecal samples of patients with diarrhoea in Japan.

RESULTS

Although 36 (72%) of 50 E. coli O25 isolates were ST131, only 6 harboured bla_CTX-M. According to the fimH and ybbW sequences and fluoroquinolone susceptibility, H30R1 isolates were dominant (27/36; 75%) and possessed IncFII-FIA-FIB with FAB formula subtype F1:A2:B20 plasmids at a high frequency (24/27; 89%). The F1:A2:B20 plasmids possessed more resistance genes such as bla_TEM-1, aminoglycoside resistance genes and trimethoprim/sulfamethoxazole resistance genes compared with non-F1:A2:B20 plasmids. In contrast, only one bla_CTX-M-14 gene was located on the F1:A2:B20 plasmids, whereas the other three were located on IncFII (F4:A-:B-) (n = 1) and IncZ (n = 2) plasmids. Two H30Rx-ST131 isolates harboured bla_CTX-M-15: one was on the chromosome and the other on the IncFIA-R plasmid. The stability and conjugation ability of the F1:A2:B20 plasmids were compared with those of non-F1:A2:B20 plasmids, which revealed higher stability but lower conjugative ability.

CONCLUSIONS

These results suggest that E. coli H30R1-ST131 is a multidrug-resistant clone containing several resistance genes in the F1:A2:B20 plasmid, which were widely distributed before the acquisition of bla_CTX-M.

Bacteria which are highly resistant to antibiotics are not resistant hydro-alcoholic products

BACKGROUND

Preventing the emergence of antibiotic-resistant bacteria requires strict adherence to standard precautions, including hand hygiene by hydro-alcoholic friction, a technique now recommended. Our study evaluates the in vitro efficacy of an hydro-alcoholic product on four emerging resistant bacteria.

METHODS AND MATERIALS

The product was tested using the dilution-neutralization method using the NF/EN 13727+A2 standard on Staphylococcus epidermidis which is resistant to methicillin and has a reduced reaction to glycopeptide antibiotics, on Enterococcus faecium which is resistant to glycopeptides, as well as on Klebsiella pneumoniae and Pseudomonas aeruginosa which produce carbapenemases. Each of the steps was performed as a blind test on the test product as on the comparator. The surviving bacteria count was measured after 24 and 48 hours' incubation and the rate of reduction was calculated.

RESULTS

A reduction which was higher than 5 decimal logarithms was observed 30seconds after contact. The test product had an 80% bactericidal concentration on Pseudomonas aeruginosa and 40% on the three other germs. The bactericidal concentration of the comparator was 80% on the four micro-organisms.

DISCUSSION

The present study confirms the effect of hydro-alcoholic products on emerging resistant bacteria. The results make it possible to answer questions from healthcare professionals who often confuse antibiotics and antiseptics and question whether using hydro-alcoholic hand sanitizer is worth it. Proof of efficacy at 30seconds is reassuring since this time is close to that observed when evaluating practices. The data could be completed by performing in vitro tests using the NF/EN 1500 standard.

Reducing antibiotic prescribing and addressing the global problem of antibiotic resistance by targeted hygiene in the home and everyday life settings: A position paper

Antimicrobial resistance (AMR) continues to threaten global health. Although global and national AMR action plans are in place, infection prevention and control is primarily discussed in the context of health care facilities with home and everyday life settings barely addressed. As seen with the recent global SARS-CoV-2 pandemic, everyday hygiene measures can play an important role in containing the threat from infectious microorganisms. This position paper has been developed following a meeting of global experts in London, 2019. It presents evidence that home and community settings are important for infection transmission and also the acquisition and spread of AMR. It also demonstrates that the targeted hygiene approach offers a framework for maximizing protection against colonization and infections, thereby reducing antibiotic prescribing and minimizing selection pressure for the development of antibiotic resistance. If combined with the provision of clean water and sanitation, targeted hygiene can reduce the circulation of resistant bacteria in homes and communities, regardless of a country's Human Development Index (overall social and economic development). Achieving a reduction of AMR strains in health care settings requires a mirrored reduction in the community. The authors call upon national and international policy makers, health agencies, and health care professionals to further recognize the importance of targeted hygiene in the home and everyday life settings for preventing and controlling infection, in a unified quest to tackle AMR.

Characterisation of plasmids harbouring extended-spectrum cephalosporin resistance genes in Escherichia coli from French rivers

Antimicrobial resistance is a "One Health" issue that requires improved knowledge of the presence and abundance of resistant bacteria in the environment. Extended-spectrum cephalosporins (ESCs) are critically important antibiotics (CIAs), and resistance to these CIAs is often encoded by beta-lactamase genes borne on conjugative plasmids. We thus decided to characterise 21 plasmids of ESC-resistant Escherichia coli randomly selected from isolates previously obtained from river water collected in a rural area in western France. The plasmids encoding ESC resistance were sequenced to investigate the diversity of the genes encoding ESC resistance and their genetic context. Sequences revealed that eleven IncI1 pMLST3 plasmids carried the bla_CTX-M-1 and sul2 genes, and some of them also had the tet(A), aadA5 or dfrA17 genes. The bla_CTX-M-1 gene was also detected on an IncN plasmid. Five plasmids obtained from four rivers contained bla_CTX-M-14, either on IncI1 or on IncFII plasmids. Two strains from two rivers contained bla_CTX-M-15 on IncN pMLST7 plasmids, with qnrS1 and dfrA14 genes. One plasmid contained the bla_CTX-M-55, a bla_TEM-1B-like, and fosA genes. One plasmid contained the bla_CMY-2 gene. The diversity of the genes and plasmids of the resistant bacteria isolated from French rivers is probably related to the various animal and human origins of the isolated bacteria.

A Comprehensive Account of Escherichia coli Sequence Type 131 in Wastewater Reveals an Abundance of Fluoroquinolone-Resistant Clade A Strains

In the ten years since its discovery, the Escherichia coli clone sequence type 131 (ST131) has become a major international health threat, with the multidrug-resistant and extended-spectrum β-lactamase (ESBL)-producing clade C emerging as the globally dominant form. ST131 has previously been isolated from wastewater; however, most of these studies selectively screened for ESBL-producing organisms, thereby missing the majority of remaining ST131 clades. In this study, we used a high-throughput PCR-based screening strategy to comprehensively examine wastewater for the presence of ST131 over a 1-year period. Additional multiplex PCRs were used to differentiate clades and obtain an unbiased account of the total ST131 population structure within the collection. Furthermore, antimicrobial susceptibility profiles of all ST131-positive samples were tested against a range of commonly used antibiotics. From a total of over 3,762 E. coli wastewater samples, 1.86% (n = 70) tested positive for ST131, with the majority being clade A isolates. In total, 63% (n = 44) were clade A, 29% (n = 20) were clade B, 1% (n = 1) were clade C0, 6% (n = 4) were clade C1, and 1% (n = 1) were clade C2. In addition, a very high rate of resistance to commonly used antibiotics among wastewater isolates is reported, with 72.7% (n = 32) of clade A resistant to ciprofloxacin and high rates of resistance to gentamicin, sulfamethoxazole-trimethoprim, and tetracycline in clades that are typically sensitive to antibiotics.IMPORTANCE ST131 is a global pathogen. This clone causes urinary tract infections and is frequently isolated from human sources. However, little is known about ST131 from environmental sources. With the widely reported increase in antibiotic concentrations found in wastewater, there is additional selection pressure for the emergence of antibiotic-resistant ST131 in this niche. The unbiased screening approach reported herein revealed that previously antibiotic-sensitive lineages of ST131 are now resistant to commonly used antibiotics present in wastewater systems and may be capable of surviving UV sterilization. This is the most comprehensive account of ST131 in the wastewater niche to date and an important step in better understanding the ecology of this global pathogen.

Prevalence and risk factors for carriage of ESBL-producing Enterobacteriaceae in a population of Dutch travellers: A cross-sectional study

BACKGROUND

We investigated prevalence and predictive factors for ESBL-E carriage in a population of mostly travellers prior to their travel (n = 2216). In addition, we examined ESBL genotype before travel and compared these to returning travellers.

METHOD

A questionnaire and faecal sample were collected before travel, and a second faecal sample was collected immediately after travel. Faecal samples were analysed for ESBL-E, with genotypic characterization by PCR and sequencing. Risk factors for ESBL-E carriage prior to travel were identified by logistic regression analyses.

RESULTS

Before travel, 136 participants (6.1%) were colonized with ESBL-E. Antibiotic use in the past three months (OR_adjusted 2.57; 95% CI 1.59-4.16) and travel outside of Europe in the past year (1.92, 1.28-2.87) were risk factors for ESBL-E colonisation prior to travel. Travel outside of Europe carried the largest attributable risk (39.8%). Prior to travel 31.3% (40/128) of participants carried blaCTX-M 15 and 21.9% (28/128) blaCTX-M 14/18. In returning travellers 633 acquired ESBL-E of who 53.4% (338/633) acquired blaCTX-M 15 and 17.7% (112/633) blaCTX-M 14/18.

CONCLUSION

In our population of Dutch travellers we found a pre-travel ESBL-E prevalence of 6.1%. Prior to travel, previous antibiotic use and travel outside of Europe were the strongest independent predictors for ESBL-E carriage, with travel outside of Europe carrying the largest attributable risk. Our molecular results suggest ESBL genes found in our study population prior to travel were in large part travel related.

Intestinal Colonization Traits of Pandemic Multidrug-Resistant Escherichia coli ST131

Background

Epidemiological studies point to the gut as a key reservoir of multidrug resistant Escherichia coli multilocus sequence type 131 (ST131), a globally dominant pathogenic clone causing urinary tract and bloodstream infections. Here we report a detailed investigation of its intestinal lifestyle.

Methods

Clinical ST131 isolates and type 1 fimbriae null mutants were assessed for colonization of human intestinal epithelia and in mouse intestinal colonization models. Mouse gut tissue underwent histologic analysis for pathology and ST131 localization. Key findings were corroborated in mucus-producing human cell lines and intestinal biopsy specimens.

Results

ST131 strains adhered to and invaded human intestinal epithelial cells more than probiotic and commensal strains. The reference ST131 strain EC958 established persistent intestinal colonization in mice, and expression of type 1 fimbriae mediated higher colonization levels. Bacterial loads were highest in the distal parts of the mouse intestine and did not cause any obvious pathology. Further analysis revealed that EC958 could bind to both mucus and underlying human intestinal epithelia.

Conclusions

ST131 strains can efficiently colonize the mammalian gut and persist long term. Type 1 fimbriae enhance ST131 intestinal colonization, suggesting that mannosides, currently developed as therapeutics for bladder infections and Crohn’s disease, could also be used to limit intestinal ST131 reservoirs.

Evaluation in general practice of the patient's feelings about a recent hospitalization and isolation for a multidrug-resistant infection

BACKGROUND

Isolation precautions used against multidrug-resistant (MDR) organisms are responsible for many emotional side effects. We evaluated patient's feeling after a hospitalization for an MDR infection.

METHODS

We conducted a qualitative study that included 11 interviews from August 2017 to June 2018. We used phenomenology and verbatim transcription analysis was performed using NVivo software. Patients reported mainly negative feelings. Among them, 4 main themes were expressed: a desire to "be free from carriage," self-questioning regarding its nosocomial origin, the reduction of the therapeutic arsenal, and the expression of many fears especially relapse.

RESULTS

For most of the participants (n = 6/11), the type of bacteria that colonized their digestive tract was precisely known including the MDR characteristics of the infection. Participants were convinced that the infection was strongly linked to the hospital and considered it as nosocomial that led to anxiety, especially regarding the origin of the infection and the absence of formal source of infection.

CONCLUSIONS

MDR infections are negatively impacting patient's lived experience even after hospital discharge, partly owing to prior implementation of isolation precautions. We need to improve communication between specialists and general practitioners to reassure the patient and his surroundings regarding the anxiety resulting from such hospitalization.

Unexpected Activity of Oral Fosfomycin against Resistant Strains of Escherichia coli in Murine Pyelonephritis

Fosfomycin tromethamine activity is well established for oral treatment of uncomplicated lower urinary tract infections, but little is known about its potential efficacy in pyelonephritis. Ascending pyelonephritis was induced in mice infected with 6 strains of Escherichia coli (fosfomycin MICs, 1 μg/ml to 256 μg/ml). The urine pH was 4.5 before infection and 5.5 to 6.0 during infection. Animals were treated for 24 h with fosfomycin (100 mg/kg of body weight subcutaneously every 4 h), and the CFU were enumerated in kidneys 24 h after the last fosfomycin injection. Peak (20.5 μg/ml at 1 h) and trough (3.5 μg/ml at 4 h) levels in plasma were comparable to those obtained in humans after an oral dose of 3 g. Fosfomycin treatment significantly reduced the bacterial loads in kidneys (3.65 log₁₀ CFU/g [range, 1.83 to 7.03 log₁₀ CFU/g] and 1.88 log₁₀ CFU/g [range, 1.78 to 5.74 log₁₀ CFU/g] in start-of-treatment control mice and treated mice, respectively; P < 10^-6). However, this effect was not found to differ across the 6 study strains (P = 0.71) or between the 3 susceptible and the 3 resistant strains (P = 0.09). Three phenomena may contribute to explain this unexpected in vivo activity: (i) in mice, the fosfomycin kidney/plasma concentration ratio increased from 1 to 7.8 (95% confidence interval, 5.2, 10.4) within 24 h in vitro when the pH decreased to 5, (ii) the fosfomycin MICs for the 3 resistant strains (64 to 256 μg/ml) decreased into the susceptible range (16 to 32 μg/ml), and (iii) maximal growth rates significantly decreased for all strains and were the lowest in urine. These results suggest that local fosfomycin concentrations and physiological conditions may favor fosfomycin activity in pyelonephritis, even against resistant strains.

Extended spectrum beta-lactamase producing Enterobacterales faecal carriage in a medical intensive care unit: low rates of cross-transmission and infection

Background

Extended-spectrum beta-lactamases-producing Enterobacterales (ESBL-E) are disseminating worldwide especially in Intensive Care Units (ICUs) and are responsible for increased health costs and mortality. The aims of this work were to study ESBL-E dissemination in ICU and to assess the impact of ESBL-E fecal carriage on subsequent infections during a non-outbreak situation.

Methods

We therefore screened every patient at admission then once a week in a medical ICU between January and June 2015. Each ESBL-E isolate was characterized by ESBL genes PCR amplification and the clonal dissemination was assessed by Pulsed-Field Gel Electrophoresis (PFGE).

Results

Among the 608 screened patients, 55 (9%) were colonized by ESBL-E. Forty-four isolates were available for further analysis. Most of them (43/44, 98%) contained a ESBL gene from the CTX-M group. Only one case of ESBL-E cross-transmission occurred, even for acquired ESBL-E colonization. Subsequent infection by ESBL-E occurred in 6/55 (11%) patients and infecting ESBL-E strains were the colonizing ones. ESBL-E faecal carriage had a negative predictive value of 100% and a positive predictive value of 40% to predict ESBL-E ventilator associated-pneumonia (VAP). Alternatives to carbapenems consisting in piperacillin-tazobactam, ceftolozane-tazobactam and ceftazidime-avibactam were all active on this panel of ESBL-E.

Conclusions

ESBL-E expansion and acquisition in ICU in a non-outbreak situation are not any more fully explained by cross-transmission. Mechanisms underlying ESBL-E dissemination in ICU are still to investigate. Interestingly, as far as we know, our study demonstrates for the first time by PFGE that the colonizing strain is indeed the infecting one in case of subsequent ESBL-E infection. Nevertheless, subsequent ESBL-E infection remains a rare event conferring poor positive predictive value for ESBL-E colonization to predict ESBL-E VAP. Relevance of systematic ESBL-E faecal screening at ICU admission and during ICU stay needs further investigation.

Association Between Kinetics of Early Biofilm Formation and Clonal Lineage in Escherichia coli

Background

Escherichia coli biofilm formation has mostly been assessed in specific pathogenic E. coli groups. Here, we assessed the early biofilm formation (EBF), i.e., adhesion stage, using the BioFilm Ring Test^® on 394 E. coli clinical isolates (EC) [196 consecutively isolated (CEC) in 2016 and 198 ESBL-producing E. coli (ESBLEC) isolated in 2015]. Then, biofilm-forming ability was contrasted with phylogroups, clonotypes (fumC-fimH), and sequence types (STs), all being used to define clones, virulence factors (VF), and FimB.

Result

According to both biofilm production levels at 2, 3, and 5 h, and EBF kinetics over 5 h, CEC and ESBLEC isolates segregated into three EBF groups: strong (G1), moderate (G2), and weak (G3) producers. At 2 h, strong producers were more frequent among CEC (n = 28; 14.3%) than among ESBLEC (n = 8; 4%) (P = 0.0004). As CEC and ESBLEC isolates showed similar individual EBF kinetics in each group, a comparison of isolate features between each group was applied to gathered CEC and ESBLEC isolates after 2 h of incubation, 2 h being the most representative time point of the CEC and ESBLEC isolate segregation into the three groups. Phylogroup B2 displayed by 51.3% of the 394 isolates was more frequent in G1 (77.8%) than in G3 (47.6%) (P = 0.0006). The 394 isolates displayed 153 clones, of which 31 included at least three isolates. B2-CH14-2-ST127, B2-CH40-22-ST131, B2-CH52-5/14-ST141, and E-CH100-96-ST362 clones were associated with G1 (P < 0.03) and accounted for 41.7% of G1 isolates. B2-CH40-30-ST131 clone was associated with G3 (P < 0.0001) and accounted for 25.5% of G3 isolates. VF mean was higher among G1 than among G3 isolates (P < 0.001). FimB-P2 variant was associated with G1 (P = 0.0011) and FimB-P1 variant was associated with G3 (P = 0.0023). Clone, some VF, and FimB were associated with EBF, with clonal lineage being able to explain 72% of the variability of EBF.

Conclusion

Among our 394 isolates, <10% are able to quickly and persistently produce high biofilm levels over 5 h. These isolates belong to a few clones previously described in various studies as dominant gut colonizers in mammalians and birds and comprised the B2-CH40-22-ST131 clone, i.e., the ancestor of the globally disseminated B2-CH40-30-ST131 clone that is the dominant clone among the weak biofilm producers.

Is systematic fecal carriage screening of extended-spectrum beta-lactamase-producing Enterobacteriaceae still useful in intensive care unit: a systematic review

BACKGROUND

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) are disseminating worldwide leading to increased hospital length of stay and mortality in intensive care units (ICU). ESBL-E dissemination was first due to outbreaks in hospital settings which led to the implementation of systematic fecal carriage screening to improve hygiene procedures by contact precautions. ESBLs have since spread in the community, and the relevance of contact precautions is questioned. ESBL-E dissemination led to an overuse of carbapenems triggering the emergence of carbapenem-resistant Enterobacteriaceae. Empirical antimicrobial therapy based on ESBL-E fecal carriage has been proposed but is debated as it could increase the consumption of carbapenems among ESBL-E carriers without any clinical benefit. Finally, selective decontamination among ESBL-E fecal carriers is evoked to decrease the risk for subsequent ESBL-E infection, but its efficacy remains debated. We propose to systematically review the evidence to recommend or not such systematic ESBL-E fecal carriage screening in adult ICU.

METHODS

Every article focusing on ESBL-E and ICU available on the MEDLINE database was assessed. Articles were included if focusing on cross-transmission, efficacy of hygiene procedures, link between ESBL-E colonization and infection or guidance of empirical therapy or selective decontamination efficacy.

RESULTS

Among 330 articles referenced on PubMed, 39 abstracts were selected for full-text assessment and 25 studies were included. Systematic screening of ESBL-E fecal carriage to guide contact precautions do not seem to decrease the rate of ESBL-E cross-transmission. It has a very good negative predictive value for subsequent ESBL-E infections but a positive predictive value between 40 and 50% and so does not help to spare carbapenems. Cessation of ESBL-E carriage systematic screening could decrease the use of carbapenems in ICU without any clinical harm. Nevertheless, further studies are needed to validate these results from monocentric before-after study. Selective decontamination strategy applied to ESBL-E fecal carriers could be helpful, but available data are conflicting.

CONCLUSION

Current knowledge lacks of high-quality evidence to strongly recommend in favor of or against a systematic ESBL-E fecal carriage screening policy for ICU patients in a non-outbreak situation. Further evaluation of selective decontamination or fecal microbiota transplantation among ESBL-E fecal carriers is needed.

Prevalence and risk factors for colonization by extended-spectrum β-lactamase-producing or ST 131 Escherichia coli among asymptomatic adults in community settings in Southern Taiwan

Purpose: Fecal carriage of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) is common in Asia, especially in China and Southeast Asia. There are no data about fecal carriage of ESBL-EC and mcr-1-positive E. coli in Taiwan, and few studies focusing on the risk factors of asymptomatic fecal carriage of epidemic ST131 E. coli have been published.

Patients and methods: From healthy inhabitants attending health examinations at a medical center in southern Taiwan in 2017, we collected 724 stool samples, which were examined for ESBL-EC fecal carriage using chromogenic medium. ST131 and mcr1-positive E. coli were also investigated using multiplex PCR. Clinical data from all participating adults were collected to analyze the risk factors for fecal ESBL-EC or ST131 E. coli carriage.

Results: The prevalence rate of asymptomatic ESBL-EC fecal carriage in adults was 1.9% (14/724). ST131 was found in 22 (3.0%) adults and mcr-1-positive E. coli was found in three (0.4%) adults. A multivariate analysis showed that the risk factors associated with ESBL-EC carriage were diabetes mellitus (adjusted odds ratio [aOR]: 5.5, 95% confidence interval [CI]: 1.3–22.7), a history of colonic polyps (aOR: 6.4, 95% CI: 1.6–24.9), and chronic renal insufficiency (aOR: 20.7, 95% CI: 1.4–305.7). Underlying cancer (aOR: 4.8, 95% CI: 1.0–22.5) and stroke (aOR: 18.0, 95% CI: 1.6–207.5) were associated with ST131 E. coli fecal carriage. In our cohort, travel to Asian countries and food habit were not associated with ST131 or ESBL-EC fecal carriage.

Conclusions: The ESBL-EC or ST131 E. coli fecal carriage rate is low among asymptomatic adults in Taiwan. Certain underlying medical conditions were associated with their fecal carriage.

Selection of ESBL-Producing E. coli in a Mouse Intestinal Colonization Model

Asymptomatic human carriage of antimicrobially drug-resistant pathogens prior to infection is increasing worldwide. Further investigation into the role of this fecal reservoir is important for combatting the increasing antimicrobial resistance problems. Additionally, the damage on the intestinal microflora due to antimicrobial treatment is still not fully understood. Animal models are powerful tools to investigate bacterial colonization subsequent to antibiotic treatment. In this chapter we present a mouse-intestinal colonization model designed to investigate how antibiotics select for an ESBL-producing E. coli isolate. The model can be used to study how antibiotics with varying effect on the intestinal flora promote the establishment of the multidrug-resistant E. coli. Colonization is successfully investigated by sampling and culturing stool during the days following administration of antibiotics. Following culturing, a precise identification of the bacterial strain found in mice feces is applied to ensure that the isolate found is in fact identical to the strain used for inoculation. For this purpose random amplified of polymorphic DNA (RAPD) PCR specifically developed for E. coli is applied. This method allows us to distinguish E. coli with more than 99.95% genome similarity using a duplex PCR method.

Assessing Transmission of Antimicrobial-Resistant Escherichia coli in Wild Giraffe Contact Networks

There is growing evidence that anthropogenic sources of antibiotics and antimicrobial-resistant bacteria can spill over into natural ecosystems, raising questions about the role wild animals play in the emergence, maintenance, and dispersal of antibiotic resistance genes. In particular, we lack an understanding of how resistance genes circulate within wild animal populations, including whether specific host characteristics, such as social associations, promote interhost transmission of these genes. In this study, we used social network analysis to explore the forces shaping population-level patterns of resistant Escherichia coli in wild giraffe (Giraffa camelopardalis) and assess the relative importance of social contact for the dissemination of resistant E. coli between giraffe. Of 195 giraffe sampled, only 5.1% harbored E. coli isolates resistant to one or more tested antibiotics. Whole-genome sequencing on a subset of resistant isolates revealed a number of acquired resistance genes with linkages to mobile genetic elements. However, we found no evidence that the spread of resistance genes among giraffe was facilitated by interhost associations. Giraffe with lower social degree were more likely to harbor resistant E. coli, but this relationship was likely driven by a correlation between an individual's social connectedness and age. Indeed, resistant E. coli was most frequently detected in socially isolated neonates, indicating that resistant E. coli may have a selective advantage in the gastrointestinal tracts of neonates compared to other age classes. Taken together, these results suggest that the maintenance of antimicrobial-resistant bacteria in wild populations may, in part, be determined by host traits and microbial competition dynamics within the host.IMPORTANCE Antimicrobial resistance represents a significant threat to human health, food security, and the global economy. To fully understand the evolution and dissemination of resistance genes, a complete picture of antimicrobial resistance in all biological compartments, including natural ecosystems, is required. The environment and wild animals may act as reservoirs for anthropogenically derived resistance genes that could be transferrable to clinically relevant bacteria of humans and domestic animals. Our study investigated the possible transmission mechanisms for antimicrobial-resistant bacteria within a wild animal population and, more broadly, contributes to our understanding of how resistance genes are spread and maintained in natural ecosystems.

Visualization-assisted binning of metagenome assemblies reveals potential new pathogenic profiles in idiopathic travelers' diarrhea

BACKGROUND

Travelers' diarrhea (TD) is often caused by enterotoxigenic Escherichia coli, enteroaggregative E. coli, other bacterial pathogens, Norovirus, and occasionally parasites. Nevertheless, standard diagnostic methods fail to identify pathogens in more than 40% of TD patients. It is predicted that new pathogens may be causative agents of the disease.

RESULTS

We performed a comprehensive amplicon and whole genome shotgun (WGS) metagenomic study of the fecal microbiomes from 23 TD patients and seven healthy travelers, all of which were negative for the known etiologic agents of TD based on standard microbiological and immunological assays. Abnormal and diverse taxonomic profiles in TD samples were revealed. WGS reads were assembled and the resulting contigs were visualized using multiple query types. A semi-manual workflow was applied to isolate independent genomes from metagenomic pools. A total of 565 genome bins were extracted, 320 of which were complete enough to be characterized as cellular genomes; 160 were viral genomes. We made predictions of the etiology of disease for many of the individual subjects based on the properties and features of the recovered genomes. Multiple patients with low-diversity metagenomes were predominated by one to several E. coli strains. Functional annotation allowed prediction of pathogenic type in many cases. Five patients were co-infected with E. coli and other members of Enterobacteriaceae, including Enterobacter, Klebsiella, and Citrobacter; these may represent blooms of organisms that appear following secretory diarrhea. New "dark matter" microbes were observed in multiple samples. In one, we identified a novel TM7 genome that phylogenetically clustered with a sludge isolate; it carries genes encoding potential virulence factors. In multiple samples, we observed high proportions of putative novel viral genomes, some of which form clusters with the ubiquitous gut virus, crAssphage. The total relative abundance of viruses was significantly higher in healthy travelers versus TD patients.

CONCLUSION

Our study highlights the strength of assembly-based metagenomics, especially the manually curated, visualization-assisted binning of contigs, in resolving unusual and under-characterized pathogenic profiles of human-associated microbiomes. Results show that TD may be polymicrobial, with multiple novel cellular and viral strains as potential players in the diarrheal disease.

Ugly bugs in healthy guts! Carriage of multidrug-resistant and ESBL-producing commensal Enterobacteriaceae in the intestine of healthy Nepalese adults

Background

Fecal carriage of multidrug-resistant and extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is one of the important risk factors for infection with antibiotic-resistant bacteria. In this report, we examined the prevalence of multidrug-resistant and ESBL-producing common enterobacterial strains colonizing the intestinal tract of apparently healthy adults in Kathmandu, Nepal.

Methods

During a 6-month period (February-July 2016), a total of 510 stool specimens were obtained from apparently healthy students of Manmohan Memorial Institute of Health Sciences, Kathmandu, Nepal. Stool specimens were cultured, and the most common enterobacterial isolates (Escherichia coli and Klebsiella species) were subjected to antimicrobial susceptibility tests according to the standard microbiologic guidelines. Multidrug-resistant isolates were selected for ESBL confirmation by combined disk test and E-test methods. Molecular characterization of plasmid-borne ESBL genes was performed by using specific primers of cefotaximase Munich (CTX-M), sulfhydryl variant (SHV), and temoniera (TEM) by polymerase chain reaction.

Results

Among 510 bacterial strains, E. coli (432, 84.71%) was the predominant organism followed by Klebsiella oxytoca (48, 9.41%) and K. pneumoniae (30, 5.88%). ESBLs were isolated in 9.8% of the total isolates including K. oxytoca (29.17%), E. coli (7.87%), and K. pneumoniae (6.67%). Among ESBLs, bla-TEM was the predominant type (92%) followed by bla-CTX-M (60%) and bla-SHV (4%).

Conclusion

Multidrug-resistant and ESBL-producing enterobacterial commensal strains among healthy individuals are of serious concern. Persistent carriage of ESBL organisms in healthy individuals suggests the possibility of sustained ESBL carriage among the diseased and hospitalized patients. We recommend similar types of epidemiologic surveys in larger communities and in hospital settings to ascertain the extent of ESBL resistance.

Prevalence and risk factors for Extended-Spectrum Beta-Lactamase-producing- Enterobacteriaceae in French military and civilian travelers: A cross-sectional analysis

BACKGROUND

International travel is a risk factor for colonization with Extended-Spectrum Beta-Lactamase-producing- Enterobacteriaceae (ESBL-E). We describe the prevalence of and risk-factors for ESBL-E colonization in civilian and military travelers.

METHODS

Patients hospitalized in the infectious diseases department of Bégin Military Hospital (France) from May 2012 to November 2015, who had traveled abroad over the past two months, were screened for intestinal colonization with ESBL-E.

RESULTS

Forty-one out of 166 travelers (24.7%) had ESBL-E colonization, predominantly Escherichia coli. The risk factors for ESBL-E colonization in the univariate analysis were a treatment with any antibiotic in the last two months (OR 4.19, 95% CI 1.91-9.16) or with a beta-lactam in the same period (OR 3.35, 95% CI 1.44-7.82), and an hospitalization in the last two months (OR 3.96, 95% CI 1.91-9.16). The military status, military mission or military accommodation were not associated with an increased risk of ESBL-E colonization. In the multivariate analysis, a treatment with any antibiotic in the last two months was significantly associated with ESBL-E colonization (OR 6.71, 95% CI 3.36-19.08).

CONCLUSION

Antibiotic treatment in the two previous months is strongly predictive of ESBL-E colonization in international travelers, while the military status and its specific living conditions are not.

Occurrence and characteristics of extended-spectrum β-lactamase- and carbapenemase- producing bacteria from hospital effluents in Singapore

One of the most important resistance mechanisms in Gram-negative bacteria today is the production of enzymes causing resistance to cephalosporin and carbapenem antibiotics. The spread of extended-spectrum β-lactamases (ESBL)- and carbapenemase- producing Gram-negative bacteria is an emerging global public health problem. The aim of the present study was to (i) assess the prevalence of carbapenem-resistant bacteria (CRB) and ESBL-producing strains in sewage effluents from two major hospitals in Singapore, (ii) characterize the isolated strains and (iii) identify some of the ESBL and carbapenemase genes responsible for the resistance. CHROMagar ESBL and KPC plates were used to rapidly screen for ESBL-producing bacteria and those expressing reduced susceptibility to carbapenems, respectively. The abundance of ESBL-producers and CRB in hospital wastewater ranged between 10³ and 10⁶CFU/mL. Out of the 66 isolates picked from ESBL and KPC plates, 95%, 82%, 82% and 76% were resistant to ceftriaxone, ceftazidime (3rd generation cephalosporin family), ertapenem and meropenem (carbapenem family), respectively. Among the resistant isolates, the most predominant taxa identified were Pseudomonas spp. (28.2%), Klebsiella spp. (28.2%), Enterobacter spp. (18.3%) and Citrobacter spp. (11.3%). PCR and sequencing analysis showed that the predominant β-lactamase genes were bla_SHV (41.1%) followed by bla_NDM-1 (35.6%), bla_CTX (35.6%) and bla_KPC (28.8%). The results of this study show a high prevalence of bacteria resistant to modern extended-spectrum cephalosporins and carbapenems and the presence of ESBL- and carbapenemase producers in hospital effluents. These findings support the need to improve management of hospital wastewater in order to minimize the spread of antimicrobial resistant microorganisms from this source.

ESBL-producing Escherichia coli in Swedish gulls-A case of environmental pollution from humans?

ESBL-producing bacteria are present in wildlife and the environment might serve as a resistance reservoir. Wild gulls have been described as frequent carriers of ESBL-producing E. coli strains with genotypic characteristics similar to strains found in humans. Therefore, potential dissemination of antibiotic resistance genes and bacteria between the human population and wildlife need to be further investigated. Occurrence and characterization of ESBL-producing E. coli in Swedish wild gulls were assessed and compared to isolates from humans, livestock and surface water collected in the same country and similar time-period. Occurrence of ESBL-producing E. coli in Swedish gulls is about three times higher in gulls compared to Swedish community carriers (17% versus 5%) and the genetic characteristics of the ESBL-producing E. coli population in Swedish wild gulls and Swedish human are similar. ESBL-plasmids IncF- and IncI1-type carrying ESBL-genes bla_CTX-M-15 or bla_CTX-M-14 were most common in isolates from both gulls and humans, but there was limited evidence of clonal transmission. Isolates from Swedish surface water harbored similar genetic characteristics, which highlights surface waters as potential dissemination routes between wildlife and the human population. Even in a low-prevalence country such as Sweden, the occurrence of ESBL producing E. coli in wild gulls and the human population appears to be connected and the occurrence of ESBL-producing E. coli in Swedish gulls is likely a case of environmental pollution.