Surveillance of antibiotic susceptibility of urinary tract pathogens for a population of 5.6 million over 4 years

Antibiotic resistances of Pseudomonas aeruginosa and Acinetobacter baumannii in urine cultures: experience in a hospital of Southeast Spain

The objectives of this study were to perform a systematic review of publications between 2010 and 2021 on the antibiotic resistance of Pseudomonas aeruginosa and Acinetobacter baumannii from urinary tract infections and to analyze changes over time in hospital urine cultures from 2016 through 2021. The literature was searched, and a retrospective cross-sectional descriptive study was performed in the hospital. Out of 21 838 positive urine cultures, 3.86% were due to P. aeruginosa and 0.44% were due to A. baumannii. For P. aeruginosa, lower resistance rates were observed to virtually all tested antibiotics than were obtained in the systematic review, and the present series of hospital samples showed an in vitro resistance rate <10% to ceftazidime, cefepime, meropenem, piperacillin-tazobactam, amikacin, tobramycin, and colistin. For A. baumannii, the resistance rates to almost all antibiotics were higher in the present series than in the systematic review, being lowest to colistin (10%). Both microorganisms show reduced in vitro susceptibility to some antibiotics during the years of the COVID-19 pandemic in comparison to previous years. In our setting, both piperacillin-tazobactam and meropenem can be recommended for the empirical treatment of UTIs by P. aeruginosa, whereas only colistin can be recommended for UTIs by A. baumannii.

Invasion and diversity in Pseudomonas aeruginosa urinary tract infections

Introduction.P. aeruginosa is an opportunistic Gram-negative pathogen frequently isolated in urinary tract infections (UTI) affecting elderly and catheterized patients and associated with ineffective antibiotic treatment and poor clinical outcomes.

Gap statement. Invasion has been shown to play an important role in UTI caused by E. coli but has only recently been studied with P. aeruginosa. The ability of P. aeruginosa to adapt and evolve in chronic lung infections is associated with resistance to antibiotics but has rarely been studied in P. aeruginosa UTI populations.

Aim. We sought to determine whether phenotypic and genotypic heterogeneity exists in P. aeruginosa UTI isolates and whether, like urinary pathogenic Escherichia coli, these could invade human bladder epithelial cells – two factors that could complicate antibiotic treatment.

Methodology.P. aeruginosa UTI samples were obtained from five elderly patients at the Royal Liverpool University Hospital as part of routine diagnostics. Fourty isolates from each patient sample were screened for a range of phenotypes. The most phenotypically diverse isolates were genome sequenced. Gentamicin protection assays and confocal microscopy were used to determine capacity to invade bladder epithelial cells.

Results. Despite significant within-patient phenotypic differences, no UTI patient was colonized by distinct strains of P. aeruginosa. Limited genotypic differences were identified in the form of non-synonymous SNPs. Gentamicin protection assays and confocal microscopy provided evidence of P. aeruginosa’s ability to invade bladder epithelial cells.

Conclusions. Phenotypic variation and cell invasion could further complicate antibiotic treatment in some patients. More work is needed to better understand P. aeruginosa UTI pathogenesis and develop more effective treatment strategies.

Dose Selection for Phase III Clinical Evaluation of Gepotidacin (GSK2140944) in the Treatment of Uncomplicated Urinary Tract Infections

Antibiotics are the current standard-of-care treatment for uncomplicated urinary tract infections (uUTIs). However, increasing rates of bacterial antibiotic resistance necessitate novel therapeutic options. Gepotidacin is a first-in-class triazaacenaphthylene antibiotic that selectively inhibits bacterial DNA replication by interaction with the bacterial subunits of DNA gyrase (GyrA) and topoisomerase IV (ParC). Gepotidacin is currently in clinical development for the treatment of uUTIs and other infections. In this article, we review data for gepotidacin from nonclinical studies, including in vitro activity, in vivo animal efficacy, and pharmacokinetic (PK) and pharmacokinetic/pharmacodynamic (PK/PD) models that informed dose selection for phase III clinical evaluation of gepotidacin. Based on this translational package of data, a gepotidacin 1,500-mg oral dose twice daily for 5 days was selected for two ongoing, randomized, multicenter, parallel-group, double-blind, double-dummy, active-comparator phase III clinical studies evaluating the safety and efficacy of gepotidacin in adolescent and adult female participants with uUTIs (ClinicalTrials.gov identifiers NCT04020341 and NCT04187144).

Imipenem-Relebactam Susceptibility Testing of Gram-Negative Bacilli by Agar Dilution, Disk Diffusion, and Gradient Strip Methods Compared with Broth Microdilution

This study aimed to determine whether agar dilution, research-use-only disk diffusion (Mast Group Ltd., Bootle Merseyside, UK), Etest (bioMérieux, Inc., Durham, NC), and MIC test strip (MTS) (Liofilchem, Inc., Waltham, MA) methods yield equivalent results to those of broth microdilution (BMD) for imipenem-relebactam susceptibility testing using a collection of 297 Gram-negative bacilli, including members of the order Enterobacterales and Pseudomonas aeruginosa, enriched for drug resistance. MIC and disk diameter results were interpreted using United States Food and Drug Administration breakpoints. Overall, 76.8% of the isolates tested were susceptible to imipenem-relebactam by BMD. MIC values for agar dilution, Etest, and MTS were not significantly different from that for BMD, although they tended to be 1 to 2 dilutions higher. Essential agreement was 95.6% for agar dilution, 90.6% for Etest, and 85.2% for MTS. Categorical agreement was 98.0% for agar dilution, 73.1% for disk diffusion, 96.3% for Etest, and 96.6% for MTS. In conclusion, agar dilution and Etest yielded comparable results to BMD for imipenem-relebactam.

Trends in antimicrobial resistance over 10 years among key bacterial pathogens from Canadian hospitals: results of the CANWARD study 2007-16

OBJECTIVES

We sought to analyse 10 years of longitudinal surveillance data (2007-16) from the CANWARD study and describe emerging trends in antimicrobial resistance for key bacterial pathogens across Canada.

METHODS

Longitudinal data from CANWARD study sites that contributed isolates every year from 2007 to 2016 were analysed to identify trends in antimicrobial resistance over time using univariate tests of trend and multivariate regression models to account for the effects of patient demographics.

RESULTS

Statistically significant increases occurred in the proportion of Escherichia coli isolates resistant to extended-spectrum cephalosporins, amoxicillin/clavulanate, trimethoprim/sulfamethoxazole and ciprofloxacin. Similarly, the proportion of Klebsiella pneumoniae isolates resistant to extended-spectrum cephalosporins, amoxicillin/clavulanate, trimethoprim/sulfamethoxazole, ciprofloxacin and carbapenems increased during the study. The proportion of Enterobacter cloacae isolates resistant to ceftazidime and trimethoprim/sulfamethoxazole increased. The proportion of both ESBL-positive E. coli and K. pneumoniae (including bloodstream isolates) increased significantly between 2007 and 2016. A reduction in the proportion of Pseudomonas aeruginosa that were ciprofloxacin, cefepime, colistin, amikacin and gentamicin resistant and an increase in the proportion of P. aeruginosa isolates non-susceptible to meropenem were observed. The proportion of isolates of Staphylococcus aureus non-susceptible to clarithromycin, clindamycin and trimethoprim/sulfamethoxazole decreased over time while an increase in the proportion of isolates of Streptococcus pneumoniae non-susceptible to clarithromycin, clindamycin and doxycycline was observed.

CONCLUSIONS

Increases in Enterobacteriaceae resistance to multiple classes of antimicrobials, increases in ESBL-positive E. coli and K. pneumoniae, and the small but significant increase in carbapenem-resistant K. pneumoniae were the most remarkable changes in antimicrobial resistance observed from 2007 to 2016 in Canada.

Routine laboratory surveillance of antimicrobial resistance in community-acquired urinary tract infections adequately informs prescribing policy in England

Objectives

To assess whether resistance estimates obtained from sentinel surveillance for antimicrobial resistance (AMR) in community-acquired urinary tract infections (UTIs) differ from routinely collected laboratory community UTI data.

Methods

All patients aged ≥18 years presenting to four sentinel general practices with a suspected UTI, from 13 November 2017 to 12 February 2018, were asked to provide urine specimens for culture and susceptibility. Specimens were processed at the local diagnostic laboratory. Antibiotic susceptibility testing was conducted using automated methods. We calculated the proportion of Escherichia coli isolates that were non-susceptible (according to contemporaneous EUCAST guidelines) to trimethoprim, nitrofurantoin, cefalexin, ciprofloxacin and amoxicillin/clavulanic acid, overall and by age group and sex, and compared this with routine estimates.

Results

Sentinel practices submitted 740 eligible specimens. The specimen submission rate had increased by 28 specimens per 1000 population per year (95% CI 21-35). Uropathogens were isolated from 23% (169/740) of specimens; 67% were E. coli (113/169). Non-susceptibility of E. coli to trimethoprim was 28.2% (95% CI 20.2-37.7) on sentinel surveillance (33.4%; 95% CI 29.5-37.6 on routine data) and to nitrofurantoin was 0.9% (95% CI 0-5.7) (1.5%; 95% CI 0.7-3.0 on routine data).

Conclusions

Routine laboratory data resulted in a small overestimation in resistance (although the difference was not statistically significant) and our findings suggest that it provides an adequate estimate of non-susceptibility to key antimicrobials in community-acquired UTIs in England. This study does not support the need for ongoing local sentinel surveillance.

Eight-Year Surveillance of Uropathogenic Escherichia coli in Southwest China

Purpose

To assess antimicrobial resistance profiles change in uropathogenic Escherichia coli (UPEC) during an 8-year period, especially extended-spectrum β-lactamase (ESBL)-producing and carbapenem-resistant isolates.

Materials and Methods

A retrospective observational study of urinary tract infections (UTIs) was performed in a territory hospital between 2012 and 2019. Isolates were identified using matrix-assisted laser desorption/ionization time of flight mass spectrometry or the VITEK 2 Compact system. The antimicrobial susceptibility testing was performed using the VITEK 2 Compact system and the modified Kirby-Bauer disc diffusion method.

Results

Of the 7713 non-repetitive UPEC isolates, 7075 (91.7%) were from inpatients and 638 (8.3%) were from outpatients. The prevalence of ESBL declined from 62.5% to 49.7% (P = 0.003). Except for cefoxitin, the resistance rates of ESBL-producing isolates were mostly higher than that of non-ESBL-producing isolates (P < 0.001). The resistance rates of ampicillin (P = 0.013), ampicillin/sulbactam (P = 0.013), ceftriaxone (P < 0.001), gentamycin (P = 0.001), tobramycin (P = 0.011), and trimethoprim/sulfamethoxazole (P = 0.028) declined slightly, while the resistance rate of imipenem increased slightly (P = 0.001). The prevalence of carbapenem-resistant Escherichia coli was <2.0%.

Conclusion

ESBL-producing Escherichia coli is still the main drug-resistant bacteria causing UTIs. We should pay attention to antimicrobial resistance in high-risk inpatient areas and take effective measures to prevent and control nosocomial infections.

Characterisation and risk factor profiling of Pseudomonas aeruginosa urinary tract infections: pinpointing those likely to be caused by multidrug-resistant strains

This study aimed to characterise UTIs caused by Pseudomonas aeruginosa in hospitalised adults and to identify risk factors for infections caused by multidrug-resistant (MDR) strains. A retrospective case-case-control study was conducted in two Italian teaching hospitals. Totally, 242 monomicrobial P. aeruginosa UTIs were analysed; 65 (26.9%) were caused by MDR strains. Clinical treatment failure at 72 h in 215 patients receiving empirical therapy was more frequent in MDR versus non-MDR cases [35/59 (59.3%) vs. 55/156 (35.3%); P = 0.001], particularly when a β-lactam/β-lactamase inhibitor or fluoroquinolone was initially prescribed. By Day 7 (when all regimens were consistent with antimicrobial susceptibility results), treatment failure rates were similar [MDR 15/65 (23.1%) vs. non-MDR 25/177 (14.1%); P = 0.09]. In-hospital mortality rates remained low in both groups [6/65 (9.2%) vs. 22/177 (12.4%); P = 0.49], but median hospital stay for MDR cases was longer (48 vs. 22 days; P ≤ 0.001). Models for predicting MDR and non-MDR P. aeruginosa UTIs displayed good discriminatory power. Presence of ≥3 risk factors for MDR P. aeruginosa UTI was associated with an OR for this outcome of 7.44 (95% CI 3.24-17.57; P < 0.001; specificity 91%, accuracy 75%). The model for predicting non-MDR P. aeruginosa UTI displayed similar accuracy (74%) with a risk factor burden threshold of ≥2 (OR = 7.02, 95% CI 4.61-10.70; P < 0.001). Risk factor assessment can identify UTIs in hospitalised patients likely to be caused by MDR P. aeruginosa, thereby facilitating targeted infection control and timelier effective treatment.

CTX-M ESBL-producing Enterobacteriaceae: estimated prevalence in adults in England in 2014

Background

ESBL-producing Enterobacteriaceae (ESBLPE) are increasing in prevalence worldwide and are more difficult to treat than non-ESBLPE. Their prevalence in the UK general population is unknown, as the only previous UK ESBLPE faecal colonization study involved patients with diarrhoea.

Objectives

To estimate the prevalence of CTX-M ESBLPE faecal colonization in the general adult population of England in 2014, and investigate risk factors.

Methods

A stratified random sample of 58 337 registered patients from 16 general practices within four areas of England were invited to participate by returning faeces specimens and self-completed questionnaires. Specimens were tested for ESBLPE and carbapenemase-producing Enterobacteriaceae (CPE).

Results

2430 individuals participated (4% of those invited). The estimated prevalence of colonization with CTX-M ESBLPE in England was 7.3% (95% CI 5.6%–9.4%) (Shropshire 774 participants, 4.9% colonization; Southampton City 740 participants, 9.2%; Newham 612 participants, 12.7%; Heart of Birmingham 234 individuals, 16.0%) and was particularly high in: those born in Afghanistan (10 participants, 60.0% colonization, 95% CI 29.7%–84.2%); those born on the Indian subcontinent (India, Pakistan, Bangladesh or Sri Lanka) (259 participants, 25.0% colonization, 95% CI 18.5%–32.9%); travellers to South Asia (India, Pakistan, Bangladesh, Sri Lanka or Nepal) in the last year (140 participants, 38.5% colonization, 95% CI 27.8%–50.5%); and healthcare domestics (8 participants, unweighted 37.5% colonization, 95% CI 8.5%–75.5%). Risk factors identified included: being born in the Indian subcontinent (aOR 5.4, 95% CI 3.0–9.7); travel to South Asia (aOR 2.9, 95% CI 1.8–4.8) or to Africa, China, South or Central America, South East or Pacific Asia or Afghanistan (aOR 2.6, 95% CI 1.7–4.1) in the last year; and working as a healthcare domestic (aOR 6.2, 95% CI 1.3–31). None of the 48 participants who took co-amoxiclav in the last year was colonized with CTX-M ESBLPE. bla_CTX-M-15 accounted for 66% of CTX-M ESBLPE positives. 0.1% (two participants) were colonized with CPE.

Conclusions

CTX-M ESBLPE are established in the general population in England and prevalence is particularly high in people from certain countries of birth or with recent travel. We recommend that these findings be taken into account in guidance on the empirical management of patients presenting with a likely Enterobacteriaceae infection.

Effect of general practice characteristics and antibiotic prescribing on Escherichia coli antibiotic non-susceptibility in the West Midlands region of England: a 4 year ecological study

Objectives

To assess the effect of general practice characteristics and antibiotic prescribing on the number of non-susceptible Escherichia coli isolated from urine specimens submitted from community settings, we undertook an ecological study of the general practice population in the West Midlands.

Methods

Descriptive analysis and multilevel modelling of temporal trends in antibiotic prescribing and non-susceptibility of E. coli urine isolates to a range of antibiotics prescribed in the community over a 4 year period.

Results

Nine of the 16 antibiotic prescribing/non-susceptibility combinations demonstrated a significant statistical linear correlation with non-susceptibility either for prescribing in a quarter or for prescribing within the previous 12 months. The magnitude of the effect varied, from a 0.3% increase in the odds of non-susceptibility to ampicillin/amoxicillin (when prescribing ampicillin/amoxicillin) to a 6.3% increase in the odds of non-susceptibility to nitrofurantoin (when prescribing nitrofurantoin) for an increase of 50 DDDs per 1000 practice population within a quarter (equivalent to ∼10 courses of antibiotics). In all 16 models, single-handed general practices were shown to have a significant association with increased numbers of non-susceptible E. coli urine isolates (adjusted ORs 1.083-1.657). Increased prescribing of ampicillin/amoxicillin in winter periods was associated with increased non-susceptibility of E. coli isolated from urine specimens.

Conclusions

Small increases in antibiotic prescribing in individual general practices reduce the number of susceptible bacteria in the practice population. To maintain the effectiveness of available treatment, antibiotic stewardship should be encouraged and supported within each practice.

Treatment of infections caused by multidrug-resistant Gram-negative bacteria: report of the British Society for Antimicrobial Chemotherapy/Healthcare Infection Society/British Infection Association Joint Working Party

The Working Party makes more than 100 tabulated recommendations in antimicrobial prescribing for the treatment of infections caused by multidrug-resistant (MDR) Gram-negative bacteria (GNB) and suggest further research, and algorithms for hospital and community antimicrobial usage in urinary infection. The international definition of MDR is complex, unsatisfactory and hinders the setting and monitoring of improvement programmes. We give a new definition of multiresistance. The background information on the mechanisms, global spread and UK prevalence of antibiotic prescribing and resistance has been systematically reviewed. The treatment options available in hospitals using intravenous antibiotics and in primary care using oral agents have been reviewed, ending with a consideration of antibiotic stewardship and recommendations. The guidance has been derived from current peer-reviewed publications and expert opinion with open consultation. Methods for systematic review were NICE compliant and in accordance with the SIGN 50 Handbook; critical appraisal was applied using AGREE II. Published guidelines were used as part of the evidence base and to support expert consensus. The guidance includes recommendations for stakeholders (including prescribers) and antibiotic-specific recommendations. The clinical efficacy of different agents is critically reviewed. We found there are very few good-quality comparative randomized clinical trials to support treatment regimens, particularly for licensed older agents. Susceptibility testing of MDR GNB causing infection to guide treatment needs critical enhancements. Meropenem- or imipenem-resistant Enterobacteriaceae should have their carbapenem MICs tested urgently, and any carbapenemase class should be identified: mandatory reporting of these isolates from all anatomical sites and specimens would improve risk assessments. Broth microdilution methods should be adopted for colistin susceptibility testing. Antimicrobial stewardship programmes should be instituted in all care settings, based on resistance rates and audit of compliance with guidelines, but should be augmented by improved surveillance of outcome in Gram-negative bacteraemia, and feedback to prescribers. Local and national surveillance of antibiotic use, resistance and outcomes should be supported and antibiotic prescribing guidelines should be informed by these data. The diagnosis and treatment of both presumptive and confirmed cases of infection by GNB should be improved. This guidance, with infection control to arrest increases in MDR, should be used to improve the outcome of infections with such strains. Anticipated users include medical, scientific, nursing, antimicrobial pharmacy and paramedical staff where they can be adapted for local use.

Variations in presentation, management, and patient outcomes of urinary tract infection: a prospective four-country primary care observational cohort study

BACKGROUND

Regional variations in the presentation of uncomplicated urinary tract infection (UTI) and pathogen sensitivity to antibiotics have been cited as reasons to justify differences in how the infections are managed, which includes the prescription of broad-spectrum antibiotics.

AIM

To describe presentation and management of UTI in primary care settings, and explore the association with patient recovery, taking microbiological findings and case mix into account.

DESIGN AND SETTING

Prospective observational study of females with symptoms of uncomplicated UTI presenting to primary care networks in England, Wales, the Netherlands, and Spain.

METHOD

Clinicians recorded history, symptom severity, management, and requested mid-stream urine culture. Participants recorded, in a diary, symptom severity each day for 14 days. Time to recovery was compared between patient characteristics and between countries using two-level Cox proportional hazards models, with patients nested within practices.

RESULTS

In total, 797 females attending primary care networks in England (n = 246, 30.9% of cohort), Wales (n = 213, 26.7%), the Netherlands (n = 133, 16.7%), and Spain (n = 205, 25.7%) were included. In total, 259 (35.8%, 95% confidence interval 32.3 to 39.2) of 726 females for whom there was a result were urine culture positive for UTI. Pathogens and antibiotic sensitivities were similar. Empirical antibiotics were prescribed for 95.1% in England, 92.9% in Wales, 95.1% in Spain, and 59.4% in the Netherlands There were no meaningful differences at a country network level before and after controlling for severity, prior UTIs, and antibiotic prescribing.

CONCLUSION

Variation in presentation and management of uncomplicated UTI at a country primary care network level is clinically unwarranted and highlights a lack of consensus concerning optimal symptom control and antibiotic prescribing.

Stratification by demographic and clinical data of the antibiotic susceptibility of Escherichia coli from urinary tract infections of the community

Aim

To determine the patterns of antibiotic susceptibility of Escherichia coli strains isolated from adult patients with urinary tract infection (UTI), and to stratify the results by age and type of UTI to verify if there are statistically significant differences that can help physicians to prescribe better empirical antibiotherapy.

Design

Cross-sectional prospective study.

Location

Community of Getafe (Madrid). Primary care level.

Participants

100 E. coli strains, randomly chosen, isolated from the urine (10⁴–10⁵ cfu/ml) of different patients from primary care centers in the Getafe area.

Main measurements

The antibiotic susceptibility of the strains was evaluated and the results were stratified by age and type of UTI. The clinical and demographic data of the patients were analyzed, classifying each episode as complicated UTI or uncomplicated UTI.

Results

Strains isolated from patients with uncomplicated UTI showed significantly greater susceptibility than those of complicated UTI to amoxicillin (65.9% vs. 30.6%, p = 0.001), amoxicillin/clavulanic acid (95.5% vs. 77.6%, p = 0.013) and ciprofloxacin (81.8% vs. 63.3%, p = 0.047). In complicated UTI, susceptibility to ciprofloxacin was significantly greater in the ≤65 years age group compared to the older age group (78.3% vs. 50%, respectively, p = 0.041). In the rest of antibiotics, no statistically significant differences were obtained when comparing by age (≤65 years versus >65 years), both in uncomplicated and complicated UTI.

Conclusions

Clinical and demographic data of patients with UTI are of great importance in the results of the antibiotic susceptibility in E. coli. Antibiograms stratified by patient characteristics may better facilitate empirical antibiotic selection for UTI in primary care.

Impact of long-term care facility residence on the antibiotic resistance of urinary tract Escherichia coli and Klebsiella

Background

Long-term care facilities (LTCFs) are thought to be important reservoirs of antimicrobial-resistant (AMR) bacteria; however, there is no routine surveillance of resistance in LTCF residents, or large population-based studies comparing AMR in LTCFs with the community, so the relative burden of AMR in LTCFs remains unknown.

Objectives

To compare the frequency of antibiotic resistance of urinary tract bacteria from residents of LTCFs for the elderly and adults aged 70 years or older living in the community.

Methods

Positive urine specimens reported to any diagnostic microbiology laboratory in the West Midlands region (England) from 1 April 2010 to 31 March 2014 collected from individuals aged 70 years or older were analysed. The resistance of Escherichia coli and Klebsiella to trimethoprim, nitrofurantoin, third-generation cephalosporins and ciprofloxacin and the rate of laboratory-confirmed E. coli and Klebsiella urinary tract infection (UTI) were assessed in LTCF residents and in the community.

Results

LTCF residents had a laboratory-confirmed E. coli and Klebsiella UTI rate of 21 per 100 person years compared with 8 per 100 person years in the elderly living in the community [rate ratio (RR)=2.66, 95% CI = 2.58-2.73] and a higher rate of developing E. coli and Klebsiella UTIs caused by bacteria resistant to trimethoprim (RR = 4.41, 95% CI = 4.25-4.57), nitrofurantoin (RR = 4.38, 95% CI = 3.98-4.83), ciprofloxacin (RR = 5.18, 95% CI = 4.82-5.57) and third-generation cephalosporins (RR = 4.49, 95% CI = 4.08-4.94).

Conclusions

Residents of LTCFs for the elderly had more than double the rate of E. coli and Klebsiella UTI and more than four times the rate of E. coli and Klebsiella UTI caused by antibiotic-resistant bacteria compared with those living in the community.

ls clinical practice aligned with the latest scientific evidence on GAG therapy?

The role of glycosaminoglycans (GAGs) as key components of the protective bladder barrier is well accepted. Replenishment of the GAG layer could restore the normal protective barrier function of the damaged bladder urothelium and re-establish normal permeability. A number of bladder diseases, including interstitial cystitis/bladder pain syndrome, recurrent urinary tract infections, radiation cystitis, and other forms of cystitis may benefit from GAG therapy.

Systematic longitudinal survey of invasive Escherichia coli in England demonstrates a stable population structure only transiently disturbed by the emergence of ST131

Escherichia coli associated with urinary tract infections and bacteremia has been intensively investigated, including recent work focusing on the virulent, globally disseminated, multidrug-resistant lineage ST131. To contextualize ST131 within the broader E. coli population associated with disease, we used genomics to analyze a systematic 11-yr hospital-based survey of E. coli associated with bacteremia using isolates collected from across England by the British Society for Antimicrobial Chemotherapy and from the Cambridge University Hospitals NHS Foundation Trust. Population dynamics analysis of the most successful lineages identified the emergence of ST131 and ST69 and their establishment as two of the five most common lineages along with ST73, ST95, and ST12. The most frequently identified lineage was ST73. Compared to ST131, ST73 was susceptible to most antibiotics, indicating that multidrug resistance was not the dominant reason for prevalence of E. coli lineages in this population. Temporal phylogenetic analysis of the emergence of ST69 and ST131 identified differences in the dynamics of emergence and showed that expansion of ST131 in this population was not driven by sequential emergence of increasingly resistant subclades. We showed that over time, the E. coli population was only transiently disturbed by the introduction of new lineages before a new equilibrium was rapidly achieved. Together, these findings suggest that the frequency of E. coli lineages in invasive disease is driven by negative frequency-dependent selection occurring outside of the hospital, most probably in the commensal niche, and that drug resistance is not a primary determinant of success in this niche.

Antibiotic resistance patterns of Escherichia coli urinary isolates and comparison with antibiotic consumption data over 10 years, 2005-2014

INTRODUCTION

Escherichia coli is a common cause of urinary tract infections (UTI). Reviews of antibiotic resistance of this organism can inform choice of empiric treatment of UTI and other infections and strategies for combating antimicrobial resistance. We reviewed laboratory and hospital pharmacy records to assess trends in non-susceptibility rates and the effect of antimicrobial stewardship interventions.

METHODS

A retrospective observational study of isolates of E. coli from MSU samples at a Dublin teaching hospital from inpatients and community, obtained from January 2005 to December 2014. Susceptibility to a panel of antibiotics was determined using the disc diffusion method, as well as extended-spectrum beta-lactamase (ESBL) production status. Trends in resistance were plotted graphically and analysed in a descriptive manner.

RESULTS

Except for nitrofurantoin and gentamicin, non-susceptibility increased for all antimicrobials tested. Co-amoxiclav non-susceptibility reached 48% in hospital and 32.6% in the community by 2014. Piperacillin-tazobactam non-susceptibility increased from 6.8 to 23.8% in hospital and from <1 to 12.5% in community, with similar increases for ESBL producing isolates. Ciprofloxacin non-susceptibility peaked at 25.5% in hospital in 2012 and 11.44% in the community in 2014.

CONCLUSION

Escherichia coli isolates from community MSU samples have high rates of non-susceptibility to trimethoprim and co-amoxiclav. Nitrofurantoin remains the best empiric therapy for cystitis. Increasing non-susceptibility to co-amoxiclav and piperacillin-tazobactam in hospital isolates is concerning. Ciprofloxacin non-susceptibility is increasing faster in the community than in hospital. A sharp reduction in hospital fluoroquinolone consumption did not result in a significant reduction in ciprofloxacin non-susceptibility of hospital E. coli isolates.

Antibiotic Resistance of Bacteria Involved in Urinary Infections in Brazil: A Cross-Sectional and Retrospective Study

Empirical and prolonged antimicrobial treatment of urinary tract infections caused by Escherichia coli is associated with the emergence of bacterial resistance, and not all countries have strict policies against the indiscriminate use of drugs in order to prevent resistance. This cross-sectional and retrospective study (2010–2015) aimed to evaluate the sensitivity and resistance of patient-derived E. coli to different drugs broadly used to treat urinary infections in Brazil: ampicillin + sulbactam, cephalothin, ciprofloxacin, norfloxacin, and nitrofurantoin. We obtained 1654 E. coli samples from ambulatory patients with disease symptoms of the urinary tract from a Brazilian public hospital. While all antibiotics were effective in killing E. coli to a large degree, nitrofurantoin was the most effective, with fewer samples exhibiting antibiotic resistance. We assessed the costs of generic and brand name versions of each antibiotic. Nitrofurantoin, the most effective antibiotic, was the cheapest, followed by the fluoroquinolones (ciprofloxacin and norfloxacin), ampicillin + sulbactam and, lastly, cephalothin. Finally, assessment of antibiotic resistance to fluoroquinolones over the study period and extrapolation of the data led to the conclusion that these antibiotics could no longer be effective against E. coli-based urinary infections in approximately 20 years if their indiscriminate use in empirical treatment continues.

Escherichia coli antimicrobial susceptibility profile and cumulative antibiogram to guide empirical treatment of uncomplicated urinary tract infections in women in the province of Québec, 2010-15

OBJECTIVES

Empirical treatment of uncomplicated urinary tract infections (UTIs) in women should be based on local susceptibility data. We aimed to generate regional and provincial cumulative antibiograms combining data from different laboratory information systems and determine the impact of basic patient characteristics on susceptibility results.

METHODS

All positive urine samples for Escherichia coli obtained from women aged 18-65 years old in outpatient settings between 1 April 2010 and 31 March 2015 from four hospitals in Quebec, Canada, were included. The cumulative antibiogram for ciprofloxacin, nitrofurantoin and trimethoprim/sulfamethoxazole was calculated. A clinically significant difference in susceptibility profile was defined as factor(s) that lowered the susceptibility proportion below 80%.

RESULTS

A total of 36 293 positive urine cultures were analysed. In the last year of the study, the proportion of susceptibility for ciprofloxacin, nitrofurantoin and trimethoprim/sulfamethoxazole was 90.3%, 95.4% and 81.9%, respectively. The susceptibility proportion was <80% for trimethoprim/sulfamethoxazole in the Montreal region (73.4%; 95% CI 71.1%-75.9%), whereas it remained >80% for the other regions. A significant decrease in susceptibility with time was identified for ciprofloxacin (92.1%-90.3%, P < 0.001) and nitrofurantoin (97.1%-95.4%, P < 0.001). Increasing age, recent hospitalization and site of collection were associated with an increase in resistance for certain antibiotics.

CONCLUSIONS

Overall, all first-line antimicrobials remain acceptable choices for empirical treatment of uncomplicated UTIs in women in Quebec. The regional variability in susceptibility data within a single province emphasizes the importance of local susceptibility data to inform the development of empirical treatment guidelines for UTIs.

Temporal trends and risks factors for antimicrobial resistant Enterobacteriaceae urinary isolates from outpatients in Guadeloupe

BACKGROUND

Urinary tract infections are bacterial infections most commonly encountered in the community. The resistance rate of uropathogens to commonly prescribed antibiotics has increased worldwide but there are no published data concerning the resistance of strains isolated from community-acquired UTI in Guadeloupe. To assess the susceptibility patterns of Enterobacteriaceae strains isolated from outpatients in Guadeloupe we conducted a prospective study from December 2012 to May 2014 among outpatients consulting at private and public laboratories for urine analysis. Risk factors for E. coli resistance to amoxicillin, third-generation cephalosporin, and ciprofloxacin were also determined. To study the trends of E. coli resistance rates over the past 10 years, data on the susceptibility patterns of E. coli from 2003 to 2014 were also collected from three major laboratories for a retrospective study.

RESULTS

During the prospective study, we isolated 1293 bacterial strains from the urine of outpatients presenting for urine analysis. The most commonly isolated bacteria were E. coli (57 %) and Klebsiella pneumoniae (15.5 %). Thirty seven per cent of the E. coli strains were resistant to amoxicillin. Resistance rates to third generation cephalosporin were low for E. coli and other Enterobacteriaceae (3.1 and 12.2 % respectively) and mostly due to the presence of an Extended Spectrum Beta-lactamase. Resistance to cotrimoxazole and ciprofloxacin was moderate (17.8 and 15.6 % respectively). However, the resistance rate of E. coli to ciprofloxacin has significantly increased during the last 10 years. Risk factors were consistent with previously reported data, especially for the increasing ciprofloxacin resistance with age.

CONCLUSION

General practitioners in Guadeloupe need to be better informed to favor the prescription of fosfomycin-trometamol to reduce the risk of resistance to fluoroquinolones.

Evolution of antibiotic multiresistance in Escherichia coli and Klebsiella pneumoniae isolates from urinary tract infections: A 12-year analysis (2003-2014)

INTRODUCTION

The aim of this study was to identify multi-drug resistance (MDR) in the main enterobacteriaceae implicated in urinary tract infections (Escherichia coli and Klebsiella pneumoniae) from both, community and hospitalized patients and to analyze the evolution over a 12-year period.

METHODS

Microb Dynamic software was used to analyze the microbiology laboratory database and a chi square test was applied to compare differences in group proportions and to determine the linear trend over 12 years in three different periods: 2003-2006, 2007-2010, 2011-2014. We chose amoxicillin, gentamicin, ciprofloxacin and trimethoprim-sulphamethoxazole as MDR markers.

RESULTS

A total of 39,980 positive urine samples were analyzed, 34,564 (3786 from hospitalized patients and 30,778 from non-hospitalized patients) E. coli isolates, and 5,422 (774 from hospitalized patients and 4,648 from non-hospitalized patients) K. pneumoniae isolates. The prevalence of UTI due to MDR E. coli and MDR K. pneumoniae significantly increased in the period studied, both in hospitalized and outpatients. A higher percentage of MDR E. coli (5.89% in 2007-2010 versus 8.18% in 2011-2014) and MDR K. pneumoniae (2.38% in 2007-2010 versus 9.35% in 2011-2014) was evident and maintained constant over time in hospitalized patients in comparison to non-hospitalized ones. Infection due to MDR ESBL-producing E. coli and K. pneumoniae increased significantly during the last 8 years in both, hospitalized (20% versus 38% and 66.8% versus 82.6%, respectively) and non-hospitalized patients (18.2% versus 23.6% and 51% versus 74.6%, respectively).

CONCLUSIONS

This study includes data of a large sample size of urinary strains isolated over a 12 year period and demonstrates that MDR is an increasing phenomenon of particular importance in the main UTI-causing species.

The Pandemic H30 Subclone of Escherichia coli Sequence Type 131 Is Associated With Persistent Infections and Adverse Outcomes Independent From Its Multidrug Resistance and Associations With Compromised Hosts

BACKGROUND

The H30 subclone within Escherichia coli sequence type 131 (ST131-H30) has emerged rapidly to become the leading antibiotic-resistant E. coli strain. Hypervirulence, multidrug resistance, and opportunism have been proposed as explanations for its epidemic success.

METHODS

We assessed 1133 consecutive unique E. coli clinical isolates from 5 medical centers (2010-2011) for H30 genotype, which we compared with epidemiological and clinical data extracted from medical records by blinded reviewers. Using univariable and multivariable logistic regression analysis, we explored associations of H30 with underlying host characteristics, clinical presentations, management, and outcomes, adjusting for host characteristics.

RESULTS

The H30 (n = 107) isolates were associated with hosts who were older, male, locally and systemically compromised, and healthcare and antibiotic exposed. With multivariable adjustment for host factors, H30 lost its numerous significant univariable associations with initial clinical presentation, but remained strongly associated with clinical persistence (odds ratio [OR], 3.47; 95% confidence interval [CI], 1.89-6.37), microbiological persistence (OR, 4.46; 95% CI, 2.38-8.38), subsequent hospital admission (OR, 2.68; 95% CI, 1.35-5.33), and subsequent new infection (OR, 1.73; 95% CI, 1.01-3.00). These host-adjusted associations remained strong even with added adjustment for resistance to the initially prescribed antibiotics, and the adverse outcome associations (subsequent hospital admission, new infection) were independent of clinical and microbiological persistence.

CONCLUSIONS

In addition to targeting compromised hosts and resisting multiple antibiotics, H30 isolates may have an intrinsic ability to cause highly persistent infections and later adverse outcomes. The basis for these host- and resistance-independent associations is unclear, but they should be considered when managing patients with H30 infections.

A Comparative Analysis of the Mechanism of Toll-Like Receptor-Disruption by TIR-Containing Protein C from Uropathogenic Escherichia coli

The TIR-containing protein C (TcpC) of uropathogenic Escherichia coli strains is a powerful virulence factor by impairing the signaling cascade of Toll-like receptors (TLRs). Several other bacterial pathogens like Salmonella, Yersinia, Staphylococcus aureus but also non-pathogens express similar proteins. We discuss here the pathogenic potential of TcpC and its interaction with TLRs and TLR-adapter proteins on the molecular level and compare its activity with the activity of other bacterial TIR-containing proteins. Finally, we analyze and compare the structure of bacterial TIR-domains with the TIR-domains of TLRs and TLR-adapters.

Antimicrobial Non-Susceptibility of Escherichia coli from Outpatients and Patients Visiting Emergency Rooms in Taiwan

Longitudinal nationwide surveillance data on antimicrobial non-susceptibility and prevalence of extended-spectrum β-lactamases (ESBLs) as well as AmpC β-lactamases producers among Escherichia coli from different sources in the community settings are limited. Such data may impact treatment practice. The present study investigated E. coli from outpatients and patients visiting emergency rooms collected by the Taiwan Surveillance of Antimicrobial Resistance (TSAR) program. A total of 3481 E. coli isolates were studied, including 2153 (61.9%) from urine and 1125 (32.3%) from blood samples. These isolates were collected biennially between 2002 and 2012 from a total of 28 hospitals located in different geographic regions of Taiwan. Minimum inhibitory concentrations (MIC) were determined using methods recommended by the Clinical Laboratory Standards Institute (CLSI). The prevalence and factors associated with the presence of ESBL and AmpC β-lactamase-producers were determined. Significant increases in non-susceptibility to most β-lactams and ciprofloxacin occurred during the study period. By 2012, non-susceptibility to cefotaxime and ciprofloxacin reached 21.1% and 26.9%, respectively. The prevalence of ESBL- and AmpC- producers also increased from 4.0% and 5.3%, respectively, in 2002–2004, to 10.7% for both in 2010–2012 (P < 0.001). The predominant ESBL and AmpC β-lactamase genes were CTX-M and CMY-types, respectively. Non-susceptibility of urine isolates to nitrofurantoin remained at around 8% and to fosfomycin was low (0.7%) but to cefazolin (based on the 2014 CLSI urine criteria) increased from 11.5% in 2002–2004 to 23.9% in 2010–2012 (P <0.001). Non-susceptibility of isolates from different specimen types was generally similar, but isolates from elderly patients were significantly more resistant to most antimicrobial agents and associated with the presence of ESBL- and AmpC- β-lactamases. An additional concern is that decreased ciprofloxacin susceptibility (MIC 0.12–1 mg/L) was as high as 25% in isolates from all age groups, including those from pediatric patients. Our data indicated that there is a need to re-evaluate appropriate treatment selection for community-acquired infections in Taiwan. Identification of community reservoirs of multidrug-resistant E. coli is also warranted.