Ertapenem for the treatment of urinary tract infections caused by extended-spectrum β-lactamase-producing bacteria in children

Antibiotic-induced gut dysbiosis elicits gut-brain axis relevant multi-omic signatures and behavioral and neuroendocrine changes in a nonhuman primate model

Emerging evidence indicates that antibiotic-induced dysbiosis can play an etiological role in the pathogenesis of neuropsychiatric disorders. However, most of this evidence comes from rodent models. The objective of this study was to evaluate if antibiotic-induced gut dysbiosis can elicit changes in gut metabolites and behavior indicative of gut-brain axis disruption in common marmosets (Callithrix jacchus) - a nonhuman primate model often used to study sociability and stress. We were able to successfully induce dysbiosis in marmosets using a custom antibiotic cocktail (vancomycin, enrofloxacin and neomycin) administered orally for 28 days. This gut dysbiosis altered gut metabolite profiles, behavior, and stress reactivity. Increase in gut Fusobacterium spp. post-antibiotic administration was a novel dysbiotic response and has not been observed in any rodent or human studies to date. There were significant changes in concentrations of several gut metabolites which are either neurotransmitters (e.g., GABA and serotonin) or have been found to be moderators of gut-brain axis communication in rodent models (e.g., short-chain fatty acids and bile acids). There was an increase in affiliative behavior and sociability in antibiotic-administered marmosets, which might be a coping mechanism in response to gut dysbiosis-induced stress. Increase in urinary cortisol levels after multiple stressors provides more definitive proof that this model of dysbiosis may cause disrupted communication between gut and brain in common marmosets. This study is a first attempt to establish common marmosets as a novel model to study the impact of severe gut dysbiosis on gut-brain axis cross-talk and behavior.

Effectiveness of ertapenem for treatment of infections in children: An evidence mapping and meta-analysis

OBJECTIVES

To assess and summarize current evidence on the effectiveness and safety of ertapenem for treatment of childhood infections, in consideration of high infection prevalence in children and wide use of ertapenem.

METHODS

The following 8 databases were searched on 13th May 2021: Web of Science, Embase via Ovid SP, PubMed, The Cochrane Library (CENTRAL), Chinese BioMedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), VIP and Wanfang. The primary outcome was treatment success rate. Risk ratios (RRs) and 95% confidence interval (CI) were estimated using random-effect models. Subgroup analysis was conducted where heterogeneity was found.

RESULTS

Fifteen studies (8 randomized controlled trials, 1 observational comparative study, and 6 before and after studies) involving 2,528 patients were included in the final review. Ertapenem had similar treatment success rates with β-lactam antibiotics [relative risk (RR) = 1.08, 95% CI: 0.99-1.19]. In a subgroup analysis, similar efficacy (RR = 1.08, 95% CI: 0.97-1.20) between ertapenem and other carbapenems. Compared with β-lactam antibiotics, ertapenem did not increase the risk of any adverse events (RR = 1.02, 95%CI: 0.71-1.48), drug-related diarrhea (all non-Asian children, RR = 0.62, 95%CI: 0.31-1.25), or injection site pain (all non-Asian children, RR = 1.66, 95%CI: 0.59-4.68). Subgroup analysis showed no obvious difference between ertapenem group and carbapenems or non-carbapenems group on risk of adverse events.

CONCLUSION

Our findings suggest that ertapenem is effective and safe in treatment for children with infection. Further comparative real-world data is needed to supplement clinical evidence on the overall benefits of ertapenem in this population.

Is it time to reconsider prophylactic antimicrobial use for hematopoietic stem cell transplantation? a narrative review of antimicrobials in stem cell transplantation

INTRODUCTION

Hematopoietic Stem Cell Transplantation (HSCT) is a life-saving procedure for multiple types of hematological cancer, autoimmune diseases, and genetic-linked metabolic diseases in humans. Recipients of HSCT transplant are at high risk of microbial infections that significantly correlate with the presence of graft-versus-host disease (GVHD) and the degree of immunosuppression. Infection in HSCT patients is a leading cause of life-threatening complications and mortality.

AREAS COVERED

This review covers issues pertinent to infection in the HSCT patient, including bacterial and viral infection; strategies to reduce GVHD; infection patterns; resistance and treatment options; adverse drug reactions to antimicrobials, problems of antimicrobial resistance; perturbation of the microbiome; the role of prebiotics, probiotics, and antimicrobial peptides. We highlight potential strategies to minimize the use of antimicrobials.

EXPERT OPINION

Measures to control infection and its transmission remain significant HSCT management policy and planning issues. Transplant centers need to consider carefully prophylactic use of antimicrobials for neutropenic patients. The judicious use of appropriate antimicrobials remains a crucial part of the treatment protocol. However, antimicrobials' adverse effects cause microbiome diversity and dysbiosis and have been shown to increase morbidity and mortality.

Enhanced quantitative urine culture technique, a slight modification, in detecting under-diagnosed pediatric urinary tract infection

Objectives

The pediatric urinary tract infection (UTI) often remains under-diagnosed or neglected owing to non-specific clinical presentations, patients failing to describe the actual situation and of clinical practice in diagnosis. The study was aimed to determine the etiologies of UTI in children with enhanced quantitative urine culture (EQUC) technique.

Results

Of enrolled 570 pediatric urine samples, the significant growth positivity was higher in EQUC 92 (16.15%) compared to standard urine culture (SUC) 73 (12.80%) technique. 20.6% of the significant isolates as detected with EQUC were missed on the SUC technique. The age group, in range 1–4 years, was more prone to the infection, where E. coli was the commonest pathogen. EQUC detected, probably all isolates, contributing UTI i.e. multidrug-resistant (MDR), extensive drug-resistant (XDR), and extended-spectrum β-lactamase (ESBL) producers, as some of them skipped on the SUC technique. Of total organisms isolated from EQUC, 46% were ESBL producer, 56.5% were MDR, and 1.4% were XDR. However, 40.5% ESBL, 44% MDR but no XDR detected on SUC. Hence a simple modification on conventional culture protocol could be a crucial modification for the detection of etiologies, contributing UTI, and hence to reduce inapt antimicrobial burden.

Antibiotics and Cure Rates in Childhood Febrile Urinary Tract Infections in Clinical Trials: A Systematic Review and Meta-analysis

PURPOSE

Urinary tract infections (UTIs) are common bacterial infections among children.

OBJECTIVE

To systematically review the antimicrobials used for febrile UTIs in paediatric clinical trials and meta-analyse the observed cure rates and reasons for treatment failure.

MATERIALS AND METHODS

We searched Medline, Embase and Cochrane central databases between January 1, 1990, and November 24, 2016, combining MeSH and free-text terms for: "urinary tract infections", AND "therapeutics", AND "clinical trials" in children (age range 0-18 years). Two independent reviewers assessed study quality and performed data extraction. The major outcome measures were clinical and microbiological cure rates according to different antibiotics.

RESULTS

We identified 2762 published studies and included 30 clinical trials investigating 3913 cases of paediatric febrile urinary tract infections. Children with no underlying condition were the main population included in the trials (n = 2602; 66.5%). Cephalosporins were the most frequent antibiotics studied in trials (22/30, 73.3%). Only a few antibiotics active against resistant UTIs have been tested in randomised clinical trials, mainly aminoglycosides. The average point cure rate of all investigational drugs was estimated to 95.3% (95% CI 93.5-96.9%). Among 3002 patients for whom cure and failure rates were reported, only 3.9% (3.9%; 118/3002) were considered clinically to have treatment failure, while 135 (4.5%; 135/3002) had microbiological failure.

CONCLUSIONS

We observed high treatment cure rates, regardless of the investigational drug chosen, the route of administration, duration and dosing. This suggests that future research should prioritise observational studies and clinical trials on children with multi-drug-resistant infections.

Treatment of Infections Caused by Extended-Spectrum-Beta-Lactamase-, AmpC-, and Carbapenemase-Producing Enterobacteriaceae

Therapy of invasive infections due to multidrug-resistant Enterobacteriaceae (MDR-E) is challenging, and some of the few active drugs are not available in many countries. For extended-spectrum β-lactamase and AmpC producers, carbapenems are the drugs of choice, but alternatives are needed because the rate of carbapenem resistance is rising. Potential active drugs include classic and newer β-lactam-β-lactamase inhibitor combinations, cephamycins, temocillin, aminoglycosides, tigecycline, fosfomycin, and, rarely, fluoroquinolones or trimethoprim-sulfamethoxazole. These drugs might be considered in some specific situations. AmpC producers are resistant to cephamycins, but cefepime is an option. In the case of carbapenemase-producing Enterobacteriaceae (CPE), only some "second-line" drugs, such as polymyxins, tigecycline, aminoglycosides, and fosfomycin, may be active; double carbapenems can also be considered in specific situations. Combination therapy is associated with better outcomes for high-risk patients, such as those in septic shock or with pneumonia. Ceftazidime-avibactam was recently approved and is active against KPC and OXA-48 producers; the available experience is scarce but promising, although development of resistance is a concern. New drugs active against some CPE isolates are in different stages of development, including meropenem-vaborbactam, imipenem-relebactam, plazomicin, cefiderocol, eravacycline, and aztreonam-avibactam. Overall, therapy of MDR-E infection must be individualized according to the susceptibility profile, type, and severity of infection and the features of the patient.

Childhood urinary tract infection caused by extended-spectrum β-lactamase-producing bacteria: Risk factors and empiric therapy

BACKGROUND

This study investigated risk factors of childhood urinary tract infection (UTI) associated with extended-spectrum β-lactamase (ESBL)-producing bacteria (ESBL-positive UTI) and evaluated antimicrobial resistance as well as empiric treatment of childhood UTI.

METHODS

The records of children with positive urine culture between 1 January 2008 and 31 December 2012 were evaluated. Patients with positive urine culture for ESBL-producing bacteria were defined as the ESBL-positive group, whereas patients of the same gender and similar age with positive urine culture for non-ESBL-producing bacteria were defined as the ESBL-negative group. Each ESBL-positive patient was matched with two ESBL-negative patients.

RESULTS

The ESBL-positive and negative groups consisted of 154 and 308 patients, respectively. Potential risk factors for ESBL-positive UTI were identified as presence of underlying disease, clean intermittent catheterization (CIC), hospitalization, use of any antibiotic and history of infection in the last 3 months (P < 0.05). On logistic regression analysis, CIC, hospitalization and history of infection in the last 3 months were identified as independent risk factors. In the present study, 324 of 462 patients had empiric therapy. Empiric therapy was inappropriate in 90.3% of the ESBL-positive group and in 4.5% of the ESBL-negative group. Resistance to nitrofurantoin was similar between groups (5.1% vs 1.2%, P = 0.072); resistance to amikacin was low in the ESBL-positive group (2.6%) and there was no resistance in the ESBL-negative group.

CONCLUSIONS

Clean intermittent catheterization, hospitalization and history of infection in the last 3 months should be considered as risk factors for ESBL-positive UTI. The combination of ampicillin plus amikacin should be taken into consideration for empiric therapy in patients with acute pyelonephritis who have the risk factors for ESBL-positive UTI. Nitrofurantoin seems to be a logical choice for the empiric therapy of cystitis.

High rates of multidrug resistance among uropathogenic Escherichia coli in children and analyses of ESBL producers from Nepal

Background

Emergence of Extended-spectrum beta-lactamase producing Escherichia coli causing urinary tract infections (UTI) among pediatric patients is an increasing problem worldwide. However, very little is known about pediatric urinary tract infections and antimicrobial resistance trend from Nepal. This study was conducted to assess the current antibiotic resistance rate and ESBL production among uropathogenic Escherichia coli in pediatric patients of a tertiary care teaching hospital of Nepal.

Methods

A total of 5,484 urinary tract specimens from children suspected with UTI attending a teaching hospital of Nepal over a period of one year were processed for the isolation of bacterial pathogens and their antimicrobial susceptibility testing. Escherichia coli (n = 739), the predominant isolate in pediatric UTI, was further selected for the detection of ESBL-production by phenotypic combination disk diffusion test.

Results

Incidence of urinary tract infection among pediatric patients was found to be 19.68% and E coli (68.4%) was leading pathogen involved. Out of 739 E coli isolates, 64.9% were multidrug resistant (MDR) and 5% were extensively drug resistant (XDR). Extended spectrum beta lactamase (ESBL) was detected in 288 (38.9%) of the E coli isolates.

Conclusion

Alarming rate of drug resistance among pediatric uropathogens and high rate of ESBL-producing E. coli was observed. It is extremely necessary to routinely investigate the drug resistance among all isolates and formulate strict antibiotics prescription policy in our country.

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.

Validation of Cefazolin as Initial Antibiotic for First Upper Urinary Tract Infection in Children

To validate the policy of administering cefazolin (CEZ) as a first-line antibiotic to children who are hospitalized with their first febrile urinary tract infection (UTI), we evaluated microbial susceptibility to CEZ and the efficacy of CEZ. The 75 enrolled children with febrile UTI were initially treated with CEZ. Switching CEZ was not required in 84% of the patients. The median fever duration, prevalence of bacteremia, prevalence of UTI caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli, and median duration of hospitalization were significantly higher in the CEZ-ineffective group. The risks of vesicoureteral reflux, indication of operation, and renal scarring are not increased, even when CEZ is ineffective as a first-line antibiotic. CEZ is effective in more than 80% of pediatric patients with their first febrile UTI, but it should be switched to appropriate antibiotics considering sepsis or the ESBL-producing Enterobacteriaceae pathogen, when fever does not improve within 72 hours.

Renal Abscess Due to Community-acquired Extended-spectrum β-Lactamase-producing Escherichia coli in a 15-Year-old Girl

Infections caused by community-acquired (CA) extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae are an increasing public health concern. We report a 15-year-old girl with a history of recurrent urinary tract infections who developed a right renal abscess. Percutaneous abscess drainage and subsequent microbiological culture revealed CA-ESBL Escherichia coli. To our knowledge, this is the first reported pediatric case of CA-ESBL E coli renal abscess complicating urinary tract infection. Establishing a definitive diagnosis of ESBL E coli renal abscess may necessitate obtaining a microbiological culture via surgical specimen, especially in children with apparent risk factors for the selection of ESBL-producing organisms.

Multidrug-Resistant Organisms: Considerations in Antibiotic Selection and Administration

Managing infections caused by multidrug-resistant organisms is a significant clinical challenge. Multidrug-resistant organisms' treatment is complicated in the pediatric population because of the lack of primary data, treatment guidelines, rapidly changing pharmacokinetic/pharmacodynamic parameters, and fewer approved antibiotic indications and dosing guidance. Treatment decisions must incorporate available pediatric data, clinical experience, and careful extrapolation from adult data while considering the unique challenges faced by children with complicated infections.

The Clinical Efficacy and Safety of Ertapenem for the Treatment of Complicated Urinary Tract Infections Caused by ESBL-Producing Bacteria in Children

Background. Urinary tract infections (UTIs) are common and important clinical problem in childhood, and extended-spectrum-beta-lactamase- (ESBL-) producing organisms are the leading cause of healthcare-related UTIs. In this study, we aimed to evaluate the clinical efficacy and safety of ertapenem therapy in children with complicated UTIs caused by ESBL-producing organisms. Methods. Seventy-seven children with complicated UTIs caused by ESBL-producing organisms were included in this retrospective study, and all had been treated with ertapenem between January 2013 and June 2014. Results. Sixty-one (79%) females and sixteen (21%) males with a mean ± standard deviation (SD) age of 76.6 ± 52 months (range 3–204, median 72 months) were enrolled in this study. Escherichia coli (E. coli) (n = 67; 87%) was the most common bacterial cause of the UTIs followed by Klebsiella pneumoniae (K. pneumoniae) (n = 9; 11.7%) and Enterobacter cloacae (E. cloacae) (n = 1; 1.3%). The mean duration of the ertapenem therapy was 8.9 ± 1.6 days (range 4–11). No serious drug-related clinical or laboratory adverse effects were observed, and the ertapenem therapy was found to be safe and well tolerated in the children in our study. Conclusion. Ertapenem is a newer carbapenem with the advantage of once-daily dosing and is highly effective for treating UTIs caused by ESBL-producing microorganisms.

Community-acquired urinary tract infection in hospitalized children: etiology and antimicrobial resistance. A comparison between first episode and recurrent infection

Urinary tract infection (UTI) is common in infants and children, and Escherichia coli is the leading pathogen. The aims of this study were to compare first episode of UTI with recurrent infection, reveal organisms that cause UTI, uropathogen resistance, and presence of bacteria producing extended-spectrum β-lactamase (ESBL). The first-UTI group included 456 children. E coli was the leading pathogen (80.5%), and Pseudomonas aeruginosa was found in 1.5%. The uropathogens were resistant to gentamicin (3.41%) and cefuroxime (5.71%), and highly resistant to cefamezin (37.39%). The recurrent-infection group included 106 children. E coli was also the leading pathogen, but 7.5% of the isolates were P aeruginosa (P = .002 compared with first-episode group); 6.6% were ESBL-producing bacteria compared with 1.1% in the first-episode group (P = .002). E coli is the leading pathogen in both groups. P aeruginosa and ESBL-producing bacteria were more common in the recurrent infection group.

Treatment of multidrug-resistant Gram-negative infections in children

Antibiotic resistance in conjunction with the erosion of the drug development pipeline may lead us into a bleak future, a "post-antibiotic era." Because of a shortage of studies addressing treatment options for multidrug-resistant Gram-negative (MDRGN) infections in children, data must be extrapolated from the adult literature. However, even adult studies are limited by significant methodological flaws. We are in urgent need of pediatric specific pharmacokinetic/pharmacodynamic data for agents with activity against MDRGN infections as well as improved clinical outcomes studies. For the time being, we must rely on in vitro studies, observational data, and clinical experience to guide our therapeutic decisions. In this review, we discuss treatment considerations for infections caused by extended-spectrum β-lactamase-producing organisms, AmpC β-lactamase-producing organisms, carbapenem-resistant Enterobacteriaceae, carbapenem-resistant Pseudomonas aeruginosa, and carbapenem-resistant Acinetobacter baumannii in the pediatric population.

Outcome of Antimicrobial Therapy of Pediatric Urinary Tract Infections Caused by Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae

Background

The purpose of this study was to compare the outcome of carbapenem versus non-carbapenem antimicrobial therapy for pediatric urinary tract infections (UTIs) caused by extended-spectrum β-lactamase (ESBL) producing Enterobacteriaceae.

Materials and Methods

From 2006 to 2011, 42 episodes of UTI caused by ESBL-producing Enterobacteriaceae were diagnosed at Seoul National University Children's Hospital. Patients were grouped according to the antimicrobials they received into a carbapenem group and a non-carbapenem group. Medical records were retrospectively reviewed to assess treatment outcome, time to defervescence after initiation of treatment, and relapse rate.

Results

There were 36 children with 42 episodes of UTI caused by ESBL-producing Enterobacteriaceae. Twenty-seven cases (64%) had an underlying urologic disease, 28 (67%) cases were caused by Escherichia coli, and 14 (33%) cases were caused by Klebsiella pneumoniae. Four (10%) cases were treated with carbapenem, 23 cases (55%) were treated with non-carbapenem, and 15 (36%) cases were treated by switching from a carbapenem to a non-carbapenem and vice versa. There was no treatment failure at the time of antimicrobial discontinuation. Between the carbapenem and the non-carbapenem treatment groups, there were no significant differences in bacterial etiology (P = 0.59), time to defervescence after the initiation of antimicrobials (P = 0.28), and relapse rate (P = 0.50). In vitro susceptibility to non-carbapenem antimicrobials did not affect the time to defervescence after the initiation of antimicrobial treatment, and the relapse rate in the non-carbapenem group.

Conclusions

This study found no significant difference in the treatment outcome between pediatric patients treated with carbapenem and those treated with non-carbapenem antimicrobials for UTI caused by ESBL-producing Enterobacteriaceae. Therefore, the initially administered non-carbapenem can be maintained in UTI patients showing clinical improvement.

Clinical pharmacology of carbapenems in neonates

Carbapenems are an effective tool to treat complicated bacterial infections. This review aims to summarize the available information on carbapenems in neonates to guide clinicians on drug choice and indications in neonates. Moreover, identification of knowledge gaps may stimulate researchers to design studies to further improve pharmacotherapy in neonates. To do so, a bibliographic search [infant/newborn and meropenem, imipenem, panipenem, ertapenem, doripenem or imipenem] was performed (PubMed, EMBASE) and public clinical trial registries (clinicaltrials.gov, EU registry) were searched to summarize the available information. Carbapenem clearance in neonates is low. Variability relates to maturation (weight, age) and renal function (creatinine clearance), while observations in neonates with renal failure are absent. Pharmacodynamics are almost exclusively limited to meropenem, and the available information will further increase (NeoMero-1-2, necrotizing enterocolitis, meningitis). Finally, there are also some ongoing doripenem pharmacokinetics (PK) studies in neonates. It was concluded that observations on carbapenems in neonates are limited, but studies (NeoMero, doripenem) are ongoing. Until this information becomes available, off label prescription of meropenem seems to be the most reasonable choice when a carbapenem is appropriate. Knowledge gaps relate to PK in neonates with renal failure and to the potential benefit of prolonged compared to short duration of infusion.

Urinary tract infections caused by community-acquired extended-spectrum β-lactamase-producing and nonproducing bacteria: a comparative study

OBJECTIVE

To study the clinical characteristics and associated risk factors of urinary tract infections (UTIs) caused by community-acquired extended-spectrum β-lactamase (CA-ESBL)-producing Enterobacteriaceae.

STUDY DESIGN

A case-control study at a large community hospital in northern Israel, comparing children who had UTI due to CA-ESBL (n = 25) and CA non-ESBL (n = 125) in 2008-2011. Data were collected from medical charts, telephonic questionnaires administered to all participants, and groups were compared.

RESULTS

During the study period, the yearly incidence of CA-ESBL UTI increased significantly. There were no significant differences between the CA-ESBL and CA non-ESBL groups in demographics and clinical outcome. Compared with CA non-ESBL UTI, children with CA-ESBL UTI had a longer hospital stay (5.9 ± 3.3 vs 3.9 ± 2.3 days; P = .003) and higher rates of recent hospitalization (28% vs 4%; P = .001), previous UTI (40% vs 13%; P = .003), urinary tract anomalies (32% vs 5%; P < .001), UTI prophylaxis with cephalexin (32% vs 2%; P < .005), and aminoglycoside resistance. In a multivariate analysis, UTI prophylaxis (OR 12.5 [CI 2.7-58]), recent hospitalization (OR 4.8 [CI 1.1-21]), and Klebsiella spp. UTI (OR 4.7 [CI 1.3-17]), were risk factors for CA-ESBL UTI.

CONCLUSIONS

Children prescribed UTI prophylaxis (due to urinary tract anomalies or recurrent UTI) with cephalexin and those with previous hospitalizations are at increased risk for CA-ESBL UTI. Although not associated with higher rates of complications, the multidrug resistant phenotype of CA-ESBL isolates poses a challenge in choosing appropriate empiric and definitive therapy and prolongs hospital stay.

Frequent emergence of porin-deficient subpopulations with reduced carbapenem susceptibility in ESBL-producing Escherichia coli during exposure to ertapenem in an in vitro pharmacokinetic model

OBJECTIVES

Ertapenem resistance is increasing in Enterobacteriaceae. The production of extended-spectrum β-lactamases (ESBLs) and reduced expression of outer membrane porins are major mechanisms of resistance in ertapenem-resistant Klebsiella pneumoniae. Less is known of ertapenem resistance in Escherichia coli. The aim of this study was to explore the impact of ESBL production in E. coli on the antibacterial activity of ertapenem.

METHODS

Two E. coli strains, with and without ESBL production, were exposed to ertapenem in vitro for 48 h at concentrations simulating human pharmacokinetics with conventional and higher dosages.

RESULTS

Isolates with non-susceptibility to ertapenem (MICs 0.75-1.5 mg/L) were detected after five of nine time-kill experiments with the ESBL-producing strain. All of these isolates had ompR mutations, which reduce the expression of outer membrane porins OmpF and OmpC. Higher dosage did not prevent selection of porin-deficient subpopulations. No mutants were detected after experiments with the non-ESBL-producing strain. Compared with other experiments, experiments with ompR mutants detected in endpoint samples showed significantly less bacterial killing after the second dose of ertapenem. Impaired antibacterial activity against E. coli with ESBL production and ompR mutation was also demonstrated in time-kill experiments with static antibiotic concentrations.

CONCLUSIONS

The combination of ESBL production and porin loss in E. coli can result in reduced susceptibility to ertapenem. Porin-deficient subpopulations frequently emerged in ESBL-producing E. coli during exposure to ertapenem at concentrations simulating human pharmacokinetics. Inappropriate use of ertapenem should be avoided to minimize the risk of selection of ESBL-producing bacteria with reduced susceptibility to carbapenems.

[Ertapenem administered intravenously or subcutaneously for urinary tract infections caused by ESBL producing enterobacteriacea]

INTRODUCTION

Ertapenem could be used to treat urinary tract infections (UTI) caused by ESBL producing enterobacteriacae (ESBL-E) and administered subcutaneously.

METHOD

The authors made a retrospective study on adult patients treated with ertapenem administered intravenously or subcutaneously for UTI caused by ESBL-E, between May 2009 and August 2011 at the Chambery hospital, France.

RESULTS

Twenty-five patients were treated (13 cases of prostatitis, ten of pyelonephritis, two of cystitis) mostly caused by Escherichia coli (24 cases). Subcutaneous injections were administered to 20 patients and 23 were treated through outpatient parenteral antibiotic therapy (OPAT). All patients were cured at the end of the ertapenem therapy. Urine samples collected during treatment for 12 patients were sterile. Three months after the end of the treatment, five patients had relapsed, and six had developed a UTI caused by another bacteria.

CONCLUSION

Ertapenem administered intravenously or subcutaneously could be an effective treatment for UTI caused by ESBL-E, especially using OPAT.