Extended-spectrum β-lactamase producing Escherichia coli: changing epidemiology and clinical impact

Multi-drug-resistant Gram-negative bacteria causing urinary tract infections: a review

Urinary tract infections (UTIs) are among the most frequent infectious diseases affecting humans, and represent an important public health problem with a substantial economic burden. Due to the high empiric use of antibiotics for the treatment of UTI, antibacterial resistance of Enterobacteriaceae, specifically the main uropathogens Escherichia coli and Klebsiella pneumoniae, has significantly increased worldwide. In this article the worldwide epidemiology of resistant Gram-negative bacteria causing UTIs, with a special focus on extended spectrum beta lactamase (ESBL) positive pathogens, as well as new threats such as multi-drug-resistant (MDR) clones (e.g. E. coli 131 (ST131) and K. pneumoniae ST258), are reviewed. The increased prevalence of MDR Enterobacteriaceae, limiting available treatment options for infections caused by these organisms, and the lack of new antibiotics provide good rationale for using older antibiotics, such as fosfomycin, that have been shown to retain some activity against MDR bacteria.

Fecal carriage of multidrug-resistant Escherichia coli by community children in southern Taiwan

BACKGROUND

The emergence of multidrug-resistant (MDR) Escherichia coli (E. coli), particularly E. coli sequence type ST131, is becoming a global concern. Commensal bacteria, an important reservoir of antibiotic resistance genes, facilitate the spread of such genes to pathogenic bacterial strains. The objective of the study is to investigate the fecal carriage of MDR E. coli and ST131 E. coli in community children in Southern Taiwan.

METHODS

In this prospective study, stool samples from children aged 0-18 years were obtained within 3 days of hospitalization from October 2013 to September 2014. Children with a history of underlying diseases, antibiotic treatment, or hospitalization in the 3 months before specimen collection were excluded. E. coli colonies were selected and tested for antimicrobial susceptibility, and O25b-ST131, multilocus sequence typing, and blaCTX-M gene groups were detected.

RESULTS

Among 157 E. coli isolates, the rates of nonsusceptibility to ampicillin, amoxycillin + clavulanate, trimethoprim-sulfamethoxazole, and cefazolin were 70, 65.6, 47.1, and 32.5%, respectively. Twenty-nine (18.5%) isolates were nonsusceptible to ciprofloxacin. MDR E. coli accounted for 58 (37%) of all isolates. Thirteen (8.3%) isolates produced extended-spectrum β-lactamase (ESBL). Furthermore, 26 (16.6%) and 13 (8.3%) isolates were O25b and ST131 positive, respectively. Five (38.5%) of the 13 ESBL-producing E. coli belonged to blaCTX-M group 9, among which were CTXM-14 and 4 (80%) were O25b-ST131 positive. Compared with the non-ESBL and ciprofloxacin-susceptible groups, the ESBL and ciprofloxacin-nonsusceptible groups showed significantly higher rates of O25b-ST131 positivity.

CONCLUSIONS

The prevalence of the fecal carriage of nonsusceptible E. coli in children was high; among these E. coli, 37% were MDR, 18.5% were nonsusceptible to ciprofloxacin, and 8.3% produced ESBL. O25b-ST131 was the most common ESBL-producing E. coli clonal group present in the feces of children, and the ESBL and ciprofloxacin-nonsusceptible groups showed significantly higher rates of O25b-ST131 positivity.

Rapid detection of ESBL, carbapenemases, MRSA and other important resistance phenotypes within 6-8 h by automated disc diffusion antibiotic susceptibility testing

Background

In principle, automated systems allow rapid reading of disc diffusion AST (rAST) within 6-8 h.

Objectives

This study analysed whether rAST can discriminate resistance phenotypes such as ESBL, carbapenemases and MRSA/methicillin-resistant Staphylococcus epidermidis from WT populations. We describe species-drug combinations that may require clinical breakpoint adaptions for early reading due to zone diameter changes during the incubation period.

Methods

In total, 1852 clinical strains [Escherichia coli (n = 475), Klebsiella pneumoniae (n = 375), Enterobacter cloacae (n = 301), Staphylococcus aureus (n = 407) and S. epidermidis (n = 294)] were included in this study comprising WT populations and important resistance phenotypes, e.g. ESBL, carbapenemases and MRSA. We assessed (i) separation of resistance phenotypes and WT populations after 6, 8 and 12 h as compared with the 18 h standard, and (ii) diameter changes of WT populations and associated putative epidemiological cut-offs during the incubation period. Disc diffusion plates were automatically streaked, incubated and imaged using the WASPLabTM system.

Results and conclusions

We demonstrated that important resistance phenotypes could reliably be separated from WT populations at early reading times for the most prevalent bacterial pathogens encountered in the clinical laboratory. Current AST expert rules and algorithms for identification of resistance mechanisms can readily be applied for rAST, e.g. EUCAST recommended rules for detection of ESBL, AmpC, carbapenemases and MRSA/methicillin-resistant S. epidermidis. However, several species-drug combinations may require clinical breakpoint adaptations when using rAST as the diameter, and hence the epidemiological cut-off, changes during the incubation period.

Trend and seasonality of community-acquired Escherichia coli antimicrobial resistance and its dynamic relationship with antimicrobial use assessed by ARIMA models

INTRODUCTION

We studied the trend and seasonality of community-acquired Escherichia coli resistance and quantified its correlation with the previous use of certain antibiotics.

METHODS

A time series study of resistant community-acquired E. coli isolates and their association with antibiotic use was conducted in a Primary Health Care Area from 2008 to 2012. A Poisson regression model was constructed to estimate the trend and seasonality of E. coli resistance.

RESULTS

A significant increasing trend in mean E. coli resistance to cephalosporins, aminoglycosides and nitrofurantoin was observed. Seasonal resistance to ciprofloxacin and amoxicillin-clavulanic acid was significantly higher in autumn-winter. There was a delay of 7, 10 and 12 months between the use of cotrimoxazole (P<0.038), fosfomycin (P<0.024) and amoxicillin-clavulanic acid (P<0.015), respectively, and the occurrence of E. coli resistance.

CONCLUSIONS

An average delay of 10 months between the previous use of amoxicillin-clavulanic acid, cotrimoxazole and fosfomycin and the appearance of resistant community-acquired E. coli strains was detected.

Structural Insights into the TLA-3 Extended-Spectrum β-Lactamase and Its Inhibition by Avibactam and OP0595

The development of effective inhibitors that block extended-spectrum β-lactamases (ESBLs) and restore the action of β-lactams represents an effective strategy against ESBL-producing Enterobacteriaceae We evaluated the inhibitory effects of the diazabicyclooctanes avibactam and OP0595 against TLA-3, an ESBL that we identified previously. Avibactam and OP0595 inhibited TLA-3 with apparent inhibitor constants (K_iapp) of 1.71 ± 0.10 and 1.49 ± 0.05 μM, respectively, and could restore susceptibility to cephalosporins in the TLA-3-producing Escherichia coli strain. The value of the second-order acylation rate constant (k₂/K, where k₂ is the acylation rate constant and K is the equilibrium constant) of avibactam [(3.25 ± 0.03) × 10³ M^-1 · s^-1] was closer to that of class C and D β-lactamases (k₂/K, <10⁴ M^-1 · s^-1) than that of class A β-lactamases (k₂/K, >10⁴ M^-1 · s^-1). In addition, we determined the structure of TLA-3 and that of TLA-3 complexed with avibactam or OP0595 at resolutions of 1.6, 1.6, and 2.0 Å, respectively. TLA-3 contains an inverted Ω loop and an extended loop between the β5 and β6 strands (insertion after Ser237), which appear only in PER-type class A β-lactamases. These structures might favor the accommodation of cephalosporins harboring bulky R1 side chains. TLA-3 presented a high catalytic efficiency (k_cat/K_m ) against cephalosporins, including cephalothin, cefuroxime, and cefotaxime. Avibactam and OP0595 bound covalently to TLA-3 via the Ser70 residue and made contacts with residues Ser130, Thr235, and Ser237, which are conserved in ESBLs. Additionally, the sulfate group of the inhibitors formed polar contacts with amino acid residues in a positively charged pocket of TLA-3. Our findings provide a structural template for designing improved diazabicyclooctane-based inhibitors that are effective against ESBL-producing Enterobacteriaceae.

Urinary tract infection caused by community-acquired extended-spectrum β-lactamase-producing bacteria in infants

OBJECTIVE

Urinary tract infection (UTI) caused by resistant strains of bacteria is increasingly prevalent in children. The aim of this study was to investigate the clinical characteristics and risk factors for UTI caused by community-acquired extended-spectrum β-lactamase (CA-ESBL)-producing bacteria in infants.

METHODS

This was a retrospective study performed over 5 years in a single Korean center. Hospitalized infants with febrile UTI were enrolled and divided into two groups (CA-ESBL vs. CA non-ESBL UTI). The yearly prevalence was calculated. Baseline characteristics and clinical course such as fever duration, laboratory and radiological findings were compared between the two groups. Risk factors associated with the CA-ESBL UTI were investigated.

RESULTS

Among the enrolled infants (n=185), 31 (17%) had CA-ESBL UTI. The yearly prevalence of ESBL of CA-ESBL UTI increased during the study (0% in 2010, 22.2% in 2015). Infants with CA-ESBL UTI had a longer duration of fever after initiating antibiotics (2.0±1.1 vs. 1.5±0.6 days, p=0.020). Cortical defects on renal scan and early treatment failure were more frequent in CA-ESBL (64.5 vs. 42.2%, p=0.023; 22.6 vs. 4.5%, p=0.001). A logistic regression analysis revealed that urinary tract abnormalities and previous UTI were independent risk factors for CA-EBSL UTI (odds ratio, 2.7; p=0.025; 10.3; p=0.022).

CONCLUSION

The incidence of UTI caused by ESBL-producing bacteria has increased in Korean infants. Recognition of the clinical course and risk factors for ESLB-producing UTI may help to determine appropriate guidelines for its management.

[Community acquired urinary tract infections - association with risk factors : Changes in causative organisms and resistance over time]

BACKGROUND

Published studies on community-acquired urinary tract infections (UTI) often do not link microbiological findings with clinical risk factors and patient data.

MATERIALS AND METHODS

We retrospectively correlated clinical findings of all patients with UTI of a urological outpatient clinic with the respective microbiological analysis of their urine samples over 2 periods of time: (A: 2005-2006 and B: 2011-2012). Patients were stratified to the following risk groups: uncomplicated cystitis, diabetes mellitus type 2, nursing home resident, prostatitis/epidydimitis, permanent catheter.

RESULTS

The incidence of Escherichia coli (p < 0.001) and proteus (p < 0.001) significantly decreased from period A to B, while enterococci (p = 0.003) and staphylococci (p < 0.001) significantly increased. Antibiotic sensitivity to fosfomycin (p < 0.001), doxycycline (p < 0.001), nitrofurantoin (p < 0.001), and nitroxoline increased (p < 0. 001) and sensitivity to amoxicillin (p < 0.001) and gentamicin decreased (p < 0.001). Patients with a permanent catheter had significantly poorer sensitivity rates (50% and less) for almost all antibiotics tested compared to the overall group. The risk of a UTI with 3MRGN or MRSA bacteria was significantly higher for catheter carriers and nursing home residents.

CONCLUSIONS

Empiric antibiotic first-line therapy with nitrofurantoin and fosfomycin for uncomplicated community acquired UTIs are well indicated in conformity with guidelines. The accumulation of multiresistant pathogens in patients with a permanent bladder catheter requires restrictive use of any permanent catheter drainage.

Fecal carriage of extended spectrum β-lactamase producing Escherichia coli and Klebsiella pneumoniae after urinary tract infection - A three year prospective cohort study

We have performed a prospective cohort study to investigate the duration of and risk factors for prolonged fecal carriage of ESBL-producing Escherichia coli or Klebsiella pneumoniae in patients with community acquired urinary tract infection caused by these bacteria. From 2009 to 2011, 101 Norwegian patients were recruited. Stool swabs and questionnaires were collected every three months for one year and at the end of the study in 2012. Information on antibiotic prescriptions was collected from the Norwegian Prescription Database. Stool samples were cultured directly on ChromID ESBL agar as well as in an enrichment broth, and culture positive isolates were examined by blaCTX-M multiplex PCR. Isolates without blaCTX-M were investigated for alternative ESBL-determinants with a commercial microarray system. Time to fecal clearance of ESBL producing Enterobacteriaceae was also analysed using Kaplan-Meier estimates. Uni- and multivariate logistic regression was used to compare groups according to previously described risk factors. The ESBL point prevalence of fecal carriage were 61% at 4 months, 56% at 7 months, 48% at 10 months, 39% at 13 months, 19% after two years, and 15% after three years or more. We found no correlation between duration of carriage, comorbidity, antibiotic use or travel to ESBL high-prevalence countries. Prolonged carriage was associated with E. coli isolates of phylogroup B2 or D. Importantly, comparative MLST and MLVA analyses of individual paired urine and fecal E. coli isolates revealed that ESBL production commonly occurred in diverse strains within the same host. When investigating cross-transmission of ESBL producing bacteria in health care institutions, this notion should be taken into account.

Detection of Escherichia coli ST131 clonal complex (ST705) and Klebsiella pneumoniae ST15 among faecal carriage of extended-spectrum β-lactamase- and carbapenemase-producing Enterobacteriaceae

PURPOSE

The objective of the present study was to evaluate the prevalence of intestinal colonization with extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) and carbapenemase-producing Enterobacteriaceae (CPE) in non-selected hospitalized and non-hospitalized patients from the same geographic area of Madrid.

METHODOLOGY

A total of 501 fecal samples were screened. Diluted samples in saline were cultured in MacConkey agar plates with ceftazidime, cefotaxime, imipenem and meropenem disks. Colonies growing within the inhibition zone of either disk were selected. Characterization of ESBLs and CPEs were performed by PCR and sequencing. The Wider system was used for the bacterial identification. In addition, clonal analysis was carried out for species predominant among the fecal carriage.

KEY FINDINGS

Among the 501 patients enrolled, 43 (8.6 %) carried ESBL-E and 8 (1.6 %) patients exhibited CPE. The main intestinal colonizer among ESBL-E was CTX-M-producing Escherichia coli isolates in both settings (community and hospital). ST131 clonal complex was the most common among faecal ESBL-producing E. coli. All gut carriers of CPE were hospitalized patients, Klebsiella pneumoniae being the most prevalent species. Two OXA-48-producing K. pneumoniae isolates belonging to ST15 were detected.

CONCLUSION

Present study reveals that faecal carriage of ESBL is common among inpatients and outpatients, whereas carbapenemase producers are only present in the hospital setting. Therefore, active surveillance will be useful for reducing transmission of antimicrobial-resistant bacteria and preventing infection.

Evaluation of reticulated gelatin-hibiscus-propolis against intestinal commensal species commonly associated with urinary tract infections

AIM

Reticulated gelatin (RG), hibiscus and propolis (RGHP) is a medical device that can reduce the bacterial adherence to epithelial cultured cells and invasion by enteropathogens, thus gathering relevant properties to decrease the risk of urinary tract infections (UTIs). We aimed at evaluating in Wistar rats the efficacy of RGHP, RG and vehicle against intestinal commensals commonly involved in UTIs.

METHODS

Animals received orally (with supplemental Na₂CO₃): RGHP 1540 mg/day/rat; RG 500 mg/day/rat or vehicle.

RESULTS

RGHP significantly reduced fecal Escherichia coli and Enterococcus spp. levels without affecting other targeted Enterobacteriaceae. The antagonistic property of RGHP was confirmed in streptomycin-pretreated rats highly colonized with a human commensal E. coli strain with uropathogenic potential.

CONCLUSION

RGHP may decrease the risk of UTIs by reducing colonization by opportunistic uropathogens.

Lethal Necrotizing Cellulitis Caused by ESBL-Producing E. Coli after Laparoscopic Intestinal Vaginoplasty

BACKGROUND

The absence of a functional vagina has a negative effect on the quality of life of women. Multiple surgical procedures have been described for vaginal reconstruction in these patients.

CASE

We present a case of an 18-year-old transgender woman, who underwent laparoscopic intestinal vaginoplasty as vaginal reconstruction, and subsequently developed septic shock and multiple organ failure on the basis of an extended-spectrum β-lactamase-producing Escherichia coli. A severe progression of the necrotizing fasciitis was lethal, despite repeated surgical debridement, intravenous antibiotic use, and supportive care at the intensive care unit.

SUMMARY AND CONCLUSION

Although vaginal reconstruction has a positive influence on the quality of life in transgender women, physicians and patients need to be aware of serious complications that might arise.

The occurrence of ESBL-producing Escherichia coli carrying aminoglycoside resistance genes in urinary tract infections in Saudi Arabia

Background

The infection and prevalence of extended-spectrum β-lactamases (ESBLs) is a worldwide problem, and the presence of ESBLs varies between countries. In this study, we investigated the occurrence of plasmid-mediated ESBL/AmpC/carbapenemase/aminoglycoside resistance gene expression in Escherichia coli using phenotypic and genotypic techniques.

Methods

A total of 58 E. coli isolates were collected from hospitals in the city of Makkah and screened for the production of ESBL/AmpC/carbapenemase/aminoglycoside resistance genes. All samples were subjected to phenotypic and genotypic analyses. The antibiotic susceptibility of the E. coli isolates was determined using the Vitek-2 system and the minimum inhibitory concentration (MIC) assay. Antimicrobial agents tested using the Vitek 2 system and MIC assay included the expanded-spectrum (or third-generation) cephalosporins (e.g., cefoxitin, cefepime, aztreonam, cefotaxime, ceftriaxone, and ceftazidime) and carbapenems (meropenem and imipenem). Reported positive isolates were investigated using genotyping technology (oligonucleotide microarray-based assay and PCR). The genotyping investigation was focused on ESBL variants and the AmpC, carbapenemase and aminoglycoside resistance genes. E. coli was phylogenetically grouped, and the clonality of the isolates was studied using multilocus sequence typing (MLST).

Results

Our E. coli isolates exhibited different levels of resistance to ESBL drugs, including ampicillin (96.61%), cefoxitin (15.25%), ciprofloxacin (79.66%), cefepime (75.58%), aztreonam (89.83%), cefotaxime (76.27%), ceftazidime (81.36%), meropenem (0%) and imipenem (0%). Furthermore, the distribution of ESBL-producing E. coli was consistent with the data obtained using an oligonucleotide microarray-based assay and PCR genotyping against genes associated with β-lactam resistance. ST131 was the dominant sequence type lineage of the isolates and was the most uropathogenic E. coli lineage. The E. coli isolates also carried aminoglycoside resistance genes.

Conclusions

The evolution and prevalence of ESBL-producing E. coli may be rapidly accelerating in Saudi Arabia due to the high visitation seasons (especially to the city of Makkah). The health authority in Saudi Arabia should monitor the level of drug resistance in all general hospitals to reduce the increasing trend of microbial drug resistance and the impact on patient therapy.

Treatment of febrile geriatric patients with suspected urinary tract infections in a hospital with high rates of ESBL producing bacteria: a cohort study

PURPOSE

To determine the consequences of treating febrile geriatric patients with a suspected urinary tract infection (UTI) with antibiotics that have high resistance rates due primarily to extended-spectrum β-lactamase (ESBL) producing bacteria.

METHODS

In this cohort study, we selected 257 consecutive hospitalised patients aged ≥70 years with a chief symptom of fever, possibly due to a UTI and initially treated with antibiotics with rates in our hospital of urinary culture resistance >20%. Patients with severe sepsis were excluded. The main outcomes measures were in vitro bacterial resistance to initial antibiotic therapy (BRIAT), response to therapy, hospitalisation days and mortality.

RESULTS

Urine cultures were positive in 64.2% (165 of 257) of the patients and BRIAT occurred in 28.0% (72 of 257). Response rates were 100% (93 of 93) in those with bacteria sensitive to initial antibiotic therapy, 95.7% (88 of 92) in the culture negative patients, and 66.7% (48 of 72) in those with BRIAT (p<0.001). There were no deaths due to deterioration during the initial treatment period because of BRIAT. In the patients with BRIAT, the median length of hospitalisation was 3 days longer than that in the other patients (7 and 4 days, respectively, p<0.001).

CONCLUSIONS

We conclude that initial broad spectrum antibiotic treatment could potentially lower the median length of hospitalisation by 3 days in many hospitalised geriatric patients without an extra-urinary tract source for their fever. This benefit needs to be balanced against the risk to the individual patient and to the general public of increasing bacterial resistance rates to broader spectrum antibiotics often held in reserve.

Acquisition of extended spectrum β-lactamases during travel abroad-A qualitative study among Swedish travellers examining their knowledge, risk assessment, and behaviour

BACKGROUND

Travel to foreign countries involves the risk of becoming a carrier of antibiotic-resistant bacteria, especially when the destination is a country with a high prevalence of this type of bacteria.

AIM AND METHODS

The aim of this study was to learn about the knowledge of antibiotic resistance, and the behaviour and risk-taking among travellers, who had become carriers of extended spectrum beta-lactamases (ESBL)-producing bacteria during travel to a high-prevalence country. A modified version of grounded theory was used to analyse 15 open interviews.

RESULTS

The analysis resulted in a core category: A need for knowledge to avoid risk-taking. Before the journey, the participants did not perceive there to be any risk of becoming a carrier of antibiotic- resistant bacteria. The low level of knowledge of antibiotic-resistant bacteria and transmission routes influenced their behaviour and risk-taking during their journey, resulting in them exposing themselves to risk situations. After their trip, the majority did not believe that their personal risk behaviour could have caused them to become carriers of ESBL.

CONCLUSION

The participants' lack of knowledge of antibiotic-resistant bacteria resulted in unconscious risk-taking during their journey, which may have resulted in becoming carriers of ESBL-producing bacteria.

Effect of kpsM on the virulence of porcine extraintestinal pathogenic Escherichia coli

In recent years, extraintestinal pathogenic Escherichia coli (ExPEC) has been found to pose a great threat to human and animal health, but its pathogenic mechanism is not fully understood yet. Capsular polysaccharide, an essential virulence factor in these bacteria, can damage the host immune system, and kpsM is a member of the gene cluster responsible for capsular polysaccharide synthesis. In this study, whole sequence alignment of the virulent strain PCN033 and the attenuated strain PCN061 revealed that kpsM exists in PCN033 but not in PCN061. To determine its function and biological characteristics, we deleted kpsM from PCN033 by homologous recombination. The results of adhesion assays, phagocytosis assays and serum bactericidal assays together with the results of colonization assays in mice indicate that the deletion of kpsM decreases the virulence of porcine ExPEC. Our findings about the biological characteristics of kpsM help to elucidate the complex pathogenic mechanism of ExPEC.

Efficacy, pharmacokinetic and pharmacodynamic profile of ceftolozane + tazobactam in the treatment of complicated urinary tract infections

INTRODUCTION

Urinary tract infections (UTIs) are the second most common nosocomially acquired infections, responsible for approximately 21% of healthcare-associated pyelonephritis and 10.5% of urosepsis. Worldwide trends of increasing resistance resulted in the urgent need for novel antimicrobials that would be active against bacterial resistance mechanisms as an alternative to carbapenems, which are considered last resort antibiotics.

AREAS COVERED

The current review is based on a Medline search of published English language literature and contains summary information regarding the evaluation of pharmacologic properties, efficacy, safety and activity of ceftolozane+tazobactam against common bacterial resistance mechanisms.

EXPERT OPINION

In vivo and vitro studies demonstrated high activity of ceftolozane+tazobactam in the combination of 2:1 against a variety of uropathogens, including ESBL-producers. Phase II and Phase III studies performed in patients with complicated UTIs showed good tolerability and safety of ceftolozane+tazobactam when prescribed intravenously 1.5 g every 8 h for 7 days and at least non-inferiority to a high dose (750 mg) of levofloxacin. The pharmacokinetics of ceftolozane+tazobactam makes it a worthy alternative to carbapenems in cases of complicated UTIs, also caused by multidrug resistant uropathogens.

Protective Effect of Curcumin on Carbapenem-Resistant Escherichia coli–Induced Lung Injury in Rats

Curcumin has remarkable anti-inflammatory and antioxidant properties. The aim of this study was to investigate the protective effects of curcumin on a rat model of carbapenem-resistant Escherichia coli–induced acute lung injury (ALI). Thirty-two rats were randomly allocated to 4 groups to induce an ALI: negative control group (rats not infected with E coli with no antibiotic treatment), positive control group (rats infected with E coli with no antibiotic treatment), imipenem group (rats infected with E coli that received intraperitoneal injection of imipenem), and the imipenem+curcumin group (rats infected with E coli that received intraperitoneal injection of imipenem and were fed on curcumin).The rats were killed, and lung tissues samples were harvested for biochemical analyses and histopathologic examination. Total antioxidant status (TAS), total oxidant status (TOS), tumor necrosis factor α (TNFα), and interleukin-6 (IL6) were measured. TOS increased in the positive control group (P &lt; 0.001) and decreased in the imipenem and imipenem+curcumin groups (P &lt; 0.001 and P &lt; 0.001, respectively). TAS decreased in the positive control group (P = 0.005). Imipenem treatment did not increase TAS, but the imipenem+curcumin group increased TAS (P = 0.014). TNFα and IL6 increased in the positive control group compared with the negative control group (P &lt; 0.001 and P = 0.010, respectively). Imipenem decreased TNFα (P &lt; 0.001), but did not decrease IL6 (P = 0.418). Imipenem+curcumin decreased TNFα (P &lt; 0.001); this decrease was more pronounced compared with the imipenem group (P = 0.008). IL6 decreased in the curcumin group compared with the positive control group (P = 0.011). Curcumin combined with imipenem can be an alternative therapeutic agent to overcome the resistance of E coli strains.

Ertapenem in outpatient parenteral antimicrobial therapy for complicated urinary tract infections

BACKGROUND

Ertapenem is a broad-spectrum antibiotic that is increasingly being utilized. Its dosing convenience renders it suitable for outpatient therapy, and its pharmacokinetic characteristics favour its use against complicated urinary tract infections (cUTIs). Despite this, sufficient clinical data are lacking for its use against cUTIs in the outpatient setting. We assessed the microbiological and clinical cure rates associated with ertapenem treatment for cUTIs in two outpatient parenteral antimicrobial therapy (OPAT) departments.

METHODS

We undertook a prospective observational study of adult patients who received ertapenem for cUTIs between August 2010 and August 2014. Data on patient characteristics, clinical progress and microbiological results were collected and analysed.

RESULTS

Sixty-one patients were enrolled. The median age was 59 years (range 24, 83) and 61% were male. The most common diagnoses were pyelonephritis (39%) and prostatitis (15%). The most common causative organism was Escherichia coli (67%). Extended-spectrum β-lactamase (ESBL)-producing organisms were detected in 72% of infections. Microbiological cure was achieved in 67% overall, and was less likely in those with Klebsiella pneumoniae infection (OR = 0.21 [95%CI: 0.05 to 0.85] p = 0.029). Clinical cure was observed in 92% of patients.

CONCLUSION

In this study of treating cUTIs with ertapenem, we have demonstrated good clinical outcomes. A lower than expected microbiological cure rate was observed in those with Klebsiella pneumoniae infection.

Carbapenemase-producing Escherichia coli is becoming more prevalent in Spain mainly because of the polyclonal dissemination of OXA-48

OBJECTIVES

The objective of this study was to analyse the microbiological traits and the population structure of carbapenemase-producing (CP) Escherichia coli isolates collected in Spain between 2012 and 2014.

METHODS

Two-hundred-and-thirty-nine E. coli isolates non-susceptible to carbapenems were studied. The carbapenemase genes and the phylogenetic groups were characterized using PCR. MLST was carried out using the typing schemes of the University of Warwick and the Institut Pasteur. The diversity of the population structure was estimated by calculating a simple diversity index (SDI).

RESULTS

One-hundred-and-twenty-one isolates (50.6%) produced carbapenemases, of which 87 (71.9%) were OXA-48, 27 (22.3%) were VIM-1, 4 (3.3%) were KPC-2, 2 (1.7%) were NDM and 1 (0.8%) was IMP-22; 4 isolates were collected in 2012, 40 in 2013 and 77 in 2014. Ertapenem was more sensitive than imipenem or meropenem for screening for OXA-48-producing E. coli. Using the Warwick typing scheme, 59 different STs were identified, the most prevalent being ST131 (16.5%). The population diversity was higher among VIM-1-producing isolates (SDI = 81.5%) than among OXA-48-producing isolates (SDI = 44.8%). The Pasteur scheme had a higher discrimination capability (SDI = 55.4%) than the Warwick scheme (SDI = 48.8%).

CONCLUSIONS

A progressive increase in the prevalence of CP E. coli was observed, mainly due to the dissemination of OXA-48 producers. The most sensitive method for detecting decreased susceptibility of CP E. coli to carbapenems was disc diffusion with ertapenem using the EUCAST screening cut-offs. The spread of CP E. coli was due to a polyclonal population. The Pasteur scheme showed the highest discrimination power. Surveillance is crucial for the early detection of CP E. coli.

LN-1-255, a penicillanic acid sulfone able to inhibit the class D carbapenemase OXA-48

OBJECTIVES

Carbapenemases are the most important mechanism responsible for carbapenem resistance in Enterobacteriaceae. Among carbapenemases, OXA-48 presents unique challenges as it is resistant to β-lactam inhibitors. Here, we test the capacity of the compound LN-1-255, a 6-alkylidene-2'-substituted penicillanic acid sulfone, to inhibit the activity of the carbapenemase OXA-48.

METHODS

The OXA-48 gene was cloned and expressed in Klebsiella pneumoniae and Escherichia coli in order to obtain MICs in the presence of inhibitors (clavulanic acid, tazobactam and sulbactam) and LN-1-255. OXA-48 was purified and steady-state kinetics was performed with LN-1-255 and tazobactam. The covalent binding mode of LN-1-255 with OXA-48 was studied by docking assays.

RESULTS

Both OXA-48-producing clinical and transformant strains displayed increased susceptibility to carbapenem antibiotics in the presence of 4 mg/L LN-1-255 (2-32-fold increased susceptibility) and 16 mg/L LN-1-255 (4-64-fold increased susceptibility). Kinetic assays demonstrated that LN-1-255 is able to inhibit OXA-48 with an acylation efficiency (k2/K) of 10 ± 1 × 10(4) M(-1) s(-1) and a slow deacylation rate (koff) of 7 ± 1 × 10(-4) s(-1). IC50 was 3 nM for LN-1-255 and 1.5 μM for tazobactam. Lastly, kcat/kinact was 500-fold lower for LN-1-255 than for tazobactam.

CONCLUSIONS

In these studies, carbapenem antibiotics used in combination with LN-1-255 are effective against the carbapenemase OXA-48, an important emerging mechanism of antibiotic resistance. This provides an incentive for further investigations to maximize the efficacy of penicillin sulfone inhibition of class D plasmid-carried Enterobacteriaceae carbapenemases.

International travel and acquisition of multidrug-resistant Enterobacteriaceae: a systematic review

International travel is considered to be an important risk factor for acquisition of multidrug-resistant Enterobacteriaceae (MRE). The aim of this systematic review was to determine the effect of international travel on the risk of post-travel faecal carriage of MRE. Secondary outcomes were risk factors for acquisition of MRE. A systematic search for relevant literature in seven international databases was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Articles needed to report on (i) foreign travel, (ii) screening of asymptomatic participants, (iii) antimicrobial susceptibility data and (iv) faecal Enterobacteriaceae carriage. Two researchers independently screened the abstracts, assessed the full article texts for eligibility and selected or rejected them for inclusion in the systematic review. In case of disagreement, a third researcher decided on inclusion. Eleven studies were identified. In all studies, a high prevalence (>20%) of carriage of MRE after international travel was found. The highest prevalence was observed in travellers returning from southern Asia. Foreign travel was associated with an increased risk of carriage of MRE. Further research is needed to assess if this leads to an increase in the number of infections with MRE. Systematic review registration number: PROSPERO CRD42015024973.

Carbon monoxide releasing molecule-2 (CORM-2) inhibits growth of multidrug-resistant uropathogenic Escherichia coli in biofilm and following host cell colonization

Background

Increased resistance to antimicrobial agents is a characteristic of many bacteria growing in biofilms on for example indwelling urinary catheters or in intracellular bacterial reservoirs. Biofilm-related infections caused by multidrug-resistant bacteria, such as extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, are a major challenge. The aim of this study was to investigate if a carbon monoxide-releasing molecule (CORM-2) has antibacterial effects against ESBL-producing uropathogenic E. coli (UPEC) in the biofilm mode of growth and following colonization of host bladder epithelial cells.

Results

The effect of CORM-2 was examined on bacteria grown within an established biofilm (biofilm formed for 24 h on plastic surface) by a live/dead viability staining assay. CORM-2 (500 μM) exposure for 24 h killed approximately 60 % of the ESBL-producing UPEC isolate. A non-ESBL-producing UPEC isolate and the E. coli K-12 strain TG1 were also sensitive to CORM-2 exposure when grown in biofilms. The antibacterial effect of CORM-2 on planktonic bacteria was reduced and delayed in the stationary growth phase compared to the exponential growth phase. In human bladder epithelial cell colonization experiments, CORM-2 exposure for 4 h significantly reduced the bacterial counts of an ESBL-producing UPEC isolate.

Conclusion

This study shows that CORM-2 has antibacterial properties against multidrug-resistant UPEC under biofilm-like conditions and following host cell colonization, which motivate further studies of its therapeutic potential.

Comparative virulotyping of extended-spectrum cephalosporin-resistant E. coli isolated from broilers, humans on broiler farms and in the general population and UTI patients

During the last decade extended-spectrum cephalosporin (ESC)-resistant Escherichia coli from food-producing animals, especially from broilers, have become a major public health concern because of the potential transmission of these resistant bacteria or their plasmid-encoded resistance genes to humans. The objective of this study was to compare ESC-resistant E. coli isolates from broilers (n=149), humans in contact with these broilers (n=44), humans in the general population (n=63), and patients with a urinary tract infection (UTI) (n=10) with respect to virulence determinants, phylogenetic groups and extended-spectrum β-lactamase (ESBL)/plasmidic-AmpC (pAmpC) genes. The most prevalent ESBL/pAmpC genes among isolates from broilers and individuals on broiler farms were bla_CTX-M-1, bla_CMY-2 and bla_SHV-12. In isolates from humans in the general population bla_CTX-M-1, bla_CTX-M-14 and bla_CTX-M-15 were found most frequently, whereas in UTI isolates bla_CTX-M-15 predominated. The marker for enteroaggregative E. coli, aggR, was only identified in a broiler and human isolates from the general population. The extraintestinal virulence genes afa and hlyD were exclusively present in human isolates in the general population and UTI isolates. Multivariate analysis, based on ESBL/pAmpC resistance genes, virulence profiles and phylogenetic groups, revealed that most UTI isolates formed a clearly distinct group. Isolates from broilers and humans associated with broiler farms clustered together. In contrast, isolates from the general population showed some overlap with the former two groups but primarily formed a separate group. These results indicate than transmission occurs between broilers and humans on broiler farms, but also indicate that the role of broilers as a source of foodborne transmission of ESC-resistant E. coli to the general population and subsequently causative agents of human urinary tract infections is likely relatively small.

A New Approach to the Treatment of Uncomplicated Cystitis: Results of a Randomized Placebo-Controlled Clinical Trial

OBJECTIVE

To assess the efficacy and safety of a new medical device (MD; a capsule whose main component is a cross-linked protein) in the prevention of uncomplicated cystitis recurrences.

METHODS

Adult women with acute cystitis symptoms and a ciprofloxacin-susceptible isolate in urine culture were included in a randomized, double-blind clinical trial. Patients were treated with ciprofloxacin 500 mg/day and 1 capsule/day or matched placebo for 5 days, 1 capsule/day or placebo for 15 additional days, and 2 additional cycles of 1 capsule/day or placebo for 15 days on months 1 and 2 after initial treatment.

RESULTS

No recurrence was observed after the first month of follow-up in the MD-treated group. In addition, symptomatic recurrence was reduced by 19.4% compared with placebo after 6 months.

CONCLUSIONS

The new MD can help prevent the recurrence of uncomplicated cystitis as well as help to reduce antibiotic use in management of urinary tract infection in women.

The prevalence of ESBL-producing Enterobacteriaceae in a nursing home setting compared with elderly living at home: a cross-sectional comparison

Background

The aim of the study was to investigate the prevalence of faecal carriage of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae among residents living in nursing homes and to compare it with a corresponding group of elderly people living in their own homes.

Methods

A total of 160 persons participated in the study between February and April 2014, 91 were residents in nursing homes (n = 10) and the remaining 69 were elderly living in their own homes. In addition to performing faecal samples, all participants answered a standardized questionnaire regarding known risk factors for ESBL-carriage.

Results

There was no significant difference between the groups, as 10 of the 91 (11 %) residents from nursing homes were ESBL-carriers compared with 6 of 69 (8,7 %) elderly living in their own homes. There was no significant difference between the groups. The total prevalence was 10 %. A univariate analysis revealed that the only studied risk factor significantly associated with ESBL-carriage was recent foreign travel (p = 0,017). All ESBL-positive isolates were Escherichia coli and there was a high degree of co-resistance to other antibiotics. All isolates (n = 17) were susceptible to imipenem and amikacin.

Conclusion

Residents of nursing homes as well as elderly living in their own homes have high rates of faecal carriage of ESBL-producing bacteria. These findings may affect the choice of empirical antibiotic treatment of severe infections in older adults.

Outbreak of multidrug-resistant Escherichia coli sequence type 131 in a neonatal intensive care unit: efficient active surveillance prevented fatal outcome

BACKGROUND

Outbreaks of infections with multidrug-resistant bacteria in neonatal intensive care units (NICUs) pose a major threat, especially to extremely preterm infants. This study describes a 35-day outbreak of multidrug-resistant Escherichia coli (E. coli) in a tertiary-level NICU in Germany.

AIM

To underline the importance of surveillance policies in the particularly vulnerable cohort of preterm infants and to describe the efficacy of outbreak control strategies.

METHODS

Data were collected retrospectively from medical reports. Infants and environment were tested for E. coli.

FINDINGS

The outbreak affected a total of 13 infants between 25(+1) and 35(+0) weeks of gestation with seven infants showing signs of infection. The outbreak strain was identified as E. coli sequence type 131. Environmental screening provided no evidence for an environmental source. Through colonization surveillance and immediate and adequate treatment of potentially infected preterm infants, no fatalities occurred. Outbreak control was achieved by strict contact precautions, enhanced screening and temporary relocation of the NICU. Relocation and reconstruction improved the NICU's structural layout, focusing on isolation capacities. Follow-up indicated carriage for several months in some infants.

CONCLUSION

Routine surveillance allowed early detection of the outbreak. The identification of carriers of the outbreak strain was successfully used to direct antibiotic treatment in case of infection. Enhanced hygienic measures and ward relocation were instrumental in controlling the outbreak.

The Increasing Challenge of Multidrug-Resistant Gram-Negative Bacilli: Results of a 5-Year Active Surveillance Program in a Neonatal Intensive Care Unit

Colonization and infection by multidrug-resistant gram-negative bacilli (MDR GNB) in neonatal intensive care units (NICUs) are increasingly reported.We conducted a 5-year prospective cohort surveillance study in a tertiary NICU of the hospital "Paolo Giaccone," Palermo, Italy. Our objectives were to describe incidence and trends of MDR GNB colonization and the characteristics of the most prevalent organisms and to identify the risk factors for colonization. Demographic, clinical, and microbiological data were prospectively collected. Active surveillance cultures (ASCs) were obtained weekly. Clusters of colonization by extended spectrum β-lactamase (ESBL) producing Escherichia coli and Klebsiella pneumoniae were analyzed by conventional and molecular epidemiological tools.During the study period, 1152 infants were enrolled in the study. Prevalences of colonization by MDR GNB, ESBL-producing GNB and multiple species/genera averaged, respectively, 28.8%, 11.7%, and 3.7%. Prevalence and incidence density of colonization by MDR GNB and ESBL-producing GNB showed an upward trend through the surveillance period. Rates of ESBL-producing E coli and K pneumoniae colonization showed wide fluctuations peaking over the last 2 years. The only independent variables associated with colonization by MDR GNB and ESBL-producing organisms and multiple colonization were, respectively, the days of NICU stay (odds ratio [OR] 1.041), the days of exposure to ampicillin-sulbactam (OR 1.040), and the days of formula feeding (OR 1.031). Most clusters of E coli and K pneumoniae colonization were associated with different lineages. Ten out of 12 clusters had an outborn infant as their index case.Our study confirms that MDR GNB are an increasing challenge to NICUs. The universal once-a-week approach allowed us to understand the epidemiology of MDR GNB, to timely detect new clones and institute contact precautions, and to assess risk factors. Collection of these data can be an important tool to optimize antimicrobials use and control the emergence and dissemination of resistances in NICU.

Social structure and Escherichia coli sharing in a group-living wild primate, Verreaux's sifaka

Background

Epidemiological models often use information on host social contacts to predict the potential impact of infectious diseases on host populations and the efficiency of control measures. It can be difficult, however, to determine whether social contacts are actually meaningful predictors of transmission. We investigated the role of host social structure in the transmission of Escherichia coli in a wild population of primates, Verreaux’s sifakas (Propithecus verreauxi). Using multilocus sequence typing (MLST), we compared genetic similarities between E. coli isolates from different individuals and groups to infer transmission pathways.

Results

Correlation of social and transmission networks revealed that membership to the same group significantly predicted sharing of E. coli MLST sequence types (ST). Intergroup encounter rate and a measure of space-use sharing provided equally potent explanations for type sharing between social groups when closely related STs were taken into account, whereas animal age, sex and dispersal history had no influence. No antibiotic resistance was found, suggesting low rates of E. coli spillover from humans into this arboreal species.

Conclusions

We show that patterns of E. coli transmission reflect the social structure of this group-living lemur species. We discuss our results in the light of the species’ ecology and propose scent-marking, a type of social contact not considered in previous epidemiological studies, as a likely route of transmission between groups. However, further studies are needed to explicitly test this hypothesis and to further elucidate the relative roles of direct contact and environmental transmission in pathogen transfer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12898-016-0059-y) contains supplementary material, which is available to authorized users.

Characteristics of CTX-M Extended-Spectrum β-Lactamase-Producing Escherichia coli Strains Isolated from Multiple Rivers in Southern Taiwan

Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli sequence type ST131 has emerged as the leading cause of community-acquired urinary tract infections and bacteremia worldwide. Whether environmental water is a potential reservoir of these strains remains unclear. River water samples were collected from 40 stations in southern Taiwan from February to August 2014. PCR assay and multilocus sequence typing (MLST) analysis were conducted to determine the CTX-M group and sequence type, respectively. In addition, we identified the seasonal frequency of ESBL-producing E. coli strains and their geographical relationship with runoffs from livestock and poultry farms between February and August 2014. ESBL-producing E. coli accounted for 30% of the 621 E. coli strains isolated from river water in southern Taiwan. ESBL-producing E. coli ST131 was not detected among the isolates. The most commonly detected strain was E. coli CTX-M group 9. Among the 92 isolates selected for MLST analysis, the most common ESBL-producing clonal complexes were ST10 and ST58. The proportion of ESBL-producing E. coli was significantly higher in areas with a lower river pollution index (P = 0.025) and regions with a large number of chickens being raised (P = 0.013). ESBL-producing E. coli strains were commonly isolated from river waters in southern Taiwan. The most commonly isolated ESBL-producing clonal complexes were ST10 and ST58, which were geographically related to chicken farms. ESBL-producing E. coli ST131, the major clone causing community-acquired infections in Taiwan and worldwide, was not detected in river waters.

[Prevalence and risk factors for extended-spectrum β-lactamase-producing Escherichia coli causing community-onset urinary tract infections in Colombia]

INTRODUCTION

Urinary tract infections (UTI) are common in the community. However, information of resistant isolates in this context is limited in Latin America. This study aims to determine the prevalence and risk factors associated with community-onset UTI (CO-UTI) caused by extended-spectrum β-lactamase (ESBL)-Producing Escherichia coli in Colombia.

MATERIALS AND METHODS

A case-control study was conducted between August and December of 2011 in three Colombian tertiary-care institutions. All patients who were admitted to the Emergency Department with a probable diagnosis of CO-UTI were invited to participate. All participating patients were asked for a urine sample. ESBL confirmatory test, antibiotic susceptibility, and molecular epidemiology were performed in these E.coli isolates (Real Time-PCR for bla genes, repetitive element palindromic PCR [rep-PCR], multilocus sequence typing [MLST] and virulence factors by PCR). Clinical and epidemiological information was recorded, and a statistical analysis was performed.

RESULTS

Of the 2124 recruited patients, 629 had a positive urine culture, 431 of which grew E.coli; 54 were positive for ESBL, of which 29 were CTX-M-15. The majority of ESBL isolates were susceptible to ertapenem, phosphomycin and amikacin. Complicated UTI was strongly associated with ESBL-producing E.coli infections (OR=3.89; 95%CI: 1.10-13.89; P=.03). CTX-M-15-producing E.coli showed 10 different pulsotypes, 65% were PT1 or PT4, and corresponded to ST131. Most of these isolates had 8 out of the 9 analysed virulence factors.

DISCUSSION

E.coli harbouring bla_CTX-M-15 associated with ST131 is still frequent in Colombia. The presence of complicated CO-UTI increases the risk of ESBL-producing E.coli, and must be taken into account in order to provide an adequate empirical therapy.