Efficacy and safety of de-escalation therapy to ertapenem for treatment of infections caused by extended-spectrum-β-lactamase-producing Enterobacteriaceae: an open-label randomized controlled trial

Efficacy and safety of a structured de-escalation from antipseudomonal β-lactams in bloodstream infections due to Enterobacterales (SIMPLIFY): an open-label, multicentre, randomised trial

BACKGROUND

De-escalation from broad-spectrum to narrow-spectrum antibiotics is considered an important measure to reduce the selective pressure of antibiotics, but a scarcity of adequate evidence is a barrier to its implementation. We aimed to determine whether de-escalation from an antipseudomonal β-lactam to a narrower-spectrum drug was non-inferior to continuing the antipseudomonal drug in patients with Enterobacterales bacteraemia.

METHODS

An open-label, pragmatic, randomised trial was performed in 21 Spanish hospitals. Patients with bacteraemia caused by Enterobacterales susceptible to one of the de-escalation options and treated empirically with an antipseudomonal β-lactam were eligible. Patients were randomly assigned (1:1; stratified by urinary source) to de-escalate to ampicillin, trimethoprim-sulfamethoxazole (urinary tract infections only), cefuroxime, cefotaxime or ceftriaxone, amoxicillin-clavulanic acid, ciprofloxacin, or ertapenem in that order according to susceptibility (de-escalation group), or to continue with the empiric antipseudomonal β-lactam (control group). Oral switching was allowed in both groups. The primary outcome was clinical cure 3-5 days after end of treatment in the modified intention-to-treat (mITT) population, formed of patients who received at least one dose of study drug. Safety was assessed in all participants. Non-inferiority was declared when the lower bound of the 95% CI of the absolute difference in cure rate was above the -10% non-inferiority margin. This trial is registered with EudraCT (2015-004219-19) and ClinicalTrials.gov (NCT02795949) and is complete.

FINDINGS

2030 patients were screened between Oct 5, 2016, and Jan 23, 2020, of whom 171 were randomly assigned to the de-escalation group and 173 to the control group. 164 (50%) patients in the de-escalation group and 167 (50%) in the control group were included in the mITT population. 148 (90%) patients in the de-escalation group and 148 (89%) in the control group had clinical cure (risk difference 1·6 percentage points, 95% CI -5·0 to 8·2). The number of adverse events reported was 219 in the de-escalation group and 175 in the control group, of these, 53 (24%) in the de-escalation group and 56 (32%) in the control group were considered severe. Seven (5%) of 164 patients in the de-escalation group and nine (6%) of 167 patients in the control group died during the 60-day follow-up. There were no treatment-related deaths.

INTERPRETATION

De-escalation from an antipseudomonal β-lactam in Enterobacterales bacteraemia following a predefined rule was non-inferior to continuing the empiric antipseudomonal drug. These results support de-escalation in this setting.

FUNDING

Plan Nacional de I+D+i 2013-2016 and Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Ciencia, Innovación y Universidades, Spanish Network for Research in Infectious Diseases; Spanish Clinical Research and Clinical Trials Platform, co-financed by the EU; European Development Regional Fund "A way to achieve Europe", Operative Program Intelligence Growth 2014-2020.

Towards optimizing carbapenem selection in stewardship strategies: a prospective propensity score-matched study of ertapenem versus class 2 carbapenems for empirical treatment of third-generation cephalosporin-resistant Enterobacterales bacteraemia

BACKGROUND

Third-generation cephalosporin-resistant Enterobacterales (3GCRE) are increasing in prevalence, leading to greater carbapenem consumption. Selecting ertapenem has been proposed as a strategy to reduce carbapenem resistance development. However, there are limited data for the efficacy of empirical ertapenem for 3GCRE bacteraemia.

OBJECTIVES

To compare the efficacy of empirical ertapenem and class 2 carbapenems for the treatment of 3GCRE bacteraemia.

METHODS

A prospective non-inferiority observational cohort study was performed from May 2019 to December 2021. Adult patients with monomicrobial 3GCRE bacteraemia receiving carbapenems within 24 h were included at two hospitals in Thailand. Propensity scores were used to control for confounding, and sensitivity analyses were performed in several subgroups. The primary outcome was 30 day mortality. This study is registered with clinicaltrials.gov (NCT03925402).

RESULTS

Empirical carbapenems were prescribed in 427/1032 (41%) patients with 3GCRE bacteraemia, of whom 221 received ertapenem and 206 received class 2 carbapenems. One-to-one propensity score matching resulted in 94 pairs. Escherichia coli was identified in 151 (80%) of cases. All patients had underlying comorbidities. Septic shock and respiratory failure were the presenting syndromes in 46 (24%) and 33 (18%) patients, respectively. The overall 30 day mortality rate was 26/188 (13.8%). Ertapenem was non-inferior to class 2 carbapenems in 30 day mortality (12.8% versus 14.9%; mean difference -0.02; 95% CI: -0.12 to 0.08). Sensitivity analyses were consistent regardless of aetiological pathogens, septic shock, source of infection, nosocomial acquisition, lactate levels or albumin levels.

CONCLUSIONS

Ertapenem may be of comparable efficacy to class 2 carbapenems in the empirical treatment of 3GCRE bacteraemia.

Strategy of elimination of antibiotcoresistance to carbapenems – actual modern problem

Strategy of elimination of antibiotcoresistance to carbapenems – actual modern problem

Implementation of Clinical Practice Guidelines for Empirical Antibiotic Therapy of Bacteremia, Urinary Tract Infection, and Pneumonia: A Multi-Center Quasi-Experimental Study

A quasi-experimental study was conducted on the implementation of locally developed clinical practice guidelines (CPGs) for empirical antibiotic (ATB) therapy of common infections (bacteremia, urinary tract infection (UTI), pneumonia) in the hospitals from January 2019 to December 2020. The CPGs were developed using data from patients with these infections at individual hospitals. Relevant CPG data pre- and post-implementation were collected and compared. Of the 1644 patients enrolled in the study, 808 and 836 were in the pre- and post-implementation periods, respectively, and patient outcomes were compared. Significant reductions in the mean durations of intensive care unit stay (3.44 ± 9.08 vs. 2.55 ± 7.89 days; p = 0.035), ventilator use (5.73 ± 12.14 vs. 4.22 ± 10.23 days; p = 0.007), piperacillin/tazobactam administration (0.954 ± 3.159 vs. 0.660 ± 2.217 days, p = 0.029), and cefoperazone/sulbactam administration (0.058 ± 0.737 vs. 0.331 ± 1.803 days, p = 0.0001) occurred. Multivariate analysis demonstrated that CPG-implementation was associated with favorable clinical outcomes (adjusted odds ratio 1.286, 95% confidence interval: 1.004–1.647, p = 0.046). Among patients who provided follow-up cultures (n = 284), favorable microbiological responses were significantly less frequent during the pre-implementation period than the post-implementation period (80.35% vs. 91.89%; p = 0.01). In conclusion, the locally developed CPG implementation is feasible and effective in improving patient outcomes and reducing ATB consumption. Hospital antimicrobial stewardship teams should be able to facilitate CPG development and implementation for antimicrobial therapy for common infections.

Thirty-Day Mortality Rates in Patients with Extended-Spectrum β-Lactamase-Producing Enterobacterales Bacteremia Receiving Ertapenem versus Other Carbapenems

Ertapenem is one of the carbapenems recommended for treating extended-spectrum β-lactamase (ESBL)-producing Enterobacterales. However, efficacy data are limited. We compared 30-day mortality rates for patients receiving ertapenem and other carbapenems for treatment of ESBL-producing Enterobacterales bacteremia. A multicenter, retrospective study was performed from January 2013 to December 2020 at three hospitals. Patients who received only members of one group of carbapenems (group 1 or group 2) throughout their treatment for ESBL-producing Escherichia coli or Klebsiella pneumoniae bacteremia were enrolled. To compare 30-day all-cause mortality rates in the two groups, propensity score matching was used to control for selection bias. Subgroup analyses were performed for several subgroups. Secondary outcomes included Clostridioides difficile infection (CDI) and the emergence of multidrug-resistant Gram-negative bacteria within 90 days after initiation of carbapenem treatment. One-to-one propensity score matching yielded 162 pairs of patients from the total of 603 patients included. There was no difference in 30-day mortality rates between ertapenem and the other carbapenems in adjusted analyses (hazard ratio, 0.60 [95% confidence interval [CI], 0.29 to 1.22]) of the propensity score-matched cohorts. A similar result was obtained in a subgroup analysis of patients who suffered severe sepsis or septic shock and those who did not (P = 0.54 for interaction). Emergence of CDI (odds ratio [OR], 0.99 [95% CI, 0.44 to 2.20]) and carbapenem-resistant Enterobacterales (OR, 1.31 [95% CI, 0.51 to 3.53]) did not differ between the two groups. Our study suggests that the efficacy of ertapenem may be comparable to that of the other carbapenems in treatment of ESBL-producing E. coli and K. pneumoniae bacteremia.

Impact of Antibiotic Authorisation at Three Provincial Hospitals in Thailand: Results from a Quasi-Experimental Study

Implementing antimicrobial stewardship (AMS) at non-university hospitals is challenging. A quasi-experimental study was conducted to determine the impact of customised antibiotic authorisation implementation on antimicrobial consumption and clinical outcomes at three provincial hospitals in Thailand. Customised pre-authorisation of selected restricted antibiotics and post-authorisation of selected controlled antibiotics were undertaken and implemented at each hospital by the local AMS team with guidance from the AMS team at the university hospital. From January 2019−December 2020, there were 1802 selected patients (901 patients during the pre-implementation period and 901 patients during the post-implementation period). The most commonly used targeted antimicrobial was meropenem (49.61%), followed by piperacillin/tazobactam (36.46%). Comparison of the outcomes of the patients during the pre- and post-implementation periods revealed that the mean day of therapy of the targeted antimicrobials was significantly shorter during the post-implementation period (6.24 vs. 7.64 days; p < 0.001), the favourable clinical response (the improvement in all clinical and laboratory parameters at the end of antibiotic therapy) was significantly higher during the post-implementation period (72.70% vs. 68.04%; p = 0.03) and the mean length of hospital stay was significantly shorter during the post-implementation period (15.78 vs. 18.90 days; p < 0.001). In conclusion, implementation of antibiotic authorisation at provincial hospitals under experienced AMS team’s guidance was feasible and useful. The study results could be a good model for the implementation of customised AMS strategies at other hospitals with limited resources.

European Society of clinical microbiology and infectious diseases (ESCMID) guidelines for the treatment of infections caused by Multidrug-resistant Gram-negative bacilli (endorsed by ESICM -European Society of intensive care Medicine)

SCOPE

These ESCMID guidelines address the targeted antibiotic treatment of 3^rd generation cephalosporin-resistant Enterobacterales (3GCephRE) and carbapenem-resistant Gram-negative bacteria, focusing on the effectiveness of individual antibiotics and on combination vs. monotherapy.

METHODS

An expert panel was convened by ESCMID. A systematic review was performed including randomized controlled trials and observational studies, examining different antibiotic treatment regimens for the targeted treatment of infections caused by the 3GCephRE, carbapenem-resistant Enterobacterales (CRE), carbapenem-resistant Pseudomonas aeruginosa (CRPA) and carbapenem-resistant Acinetobacter baumanni (CRAB). Treatments were classified as head-to-head comparisons between individual antibiotics and monotherapy vs. combination therapy regimens, including defined monotherapy and combination regimens only. The primary outcome was all-cause mortality, preferably at 30 days and secondary outcomes included clinical failure, microbiological failure, development of resistance, relapse/recurrence, adverse events and length of hospital stay. The last search of all databases was conducted in December 2019, followed by a focused search for relevant studies up until ECCMID 2021. Data were summarized narratively. The certainty of the evidence for each comparison between antibiotics and between monotherapy vs. combination therapy regimens was classified by the GRADE recommendations. The strength of the recommendations for or against treatments was classified as strong or conditional (weak).

RECOMMENDATIONS

The guideline panel reviewed the evidence per pathogen, preferably per site of infection, critically appraising the existing studies. Many of the comparisons were addressed in small observational studies at high risk of bias only. Notably, there was very little evidence on the effects of the new, recently approved, beta-lactam beta-lactamase inhibitors on infections caused by carbapenem-resistant Gram-negative bacteria. Most recommendations are based on very-low and low certainty evidence. A high value was placed on antibiotic stewardship considerations in all recommendations, searching for carbapenem-sparing options for 3GCephRE and limiting the recommendations of the new antibiotics for severe infections, as defined by the sepsis-3 criteria. Research needs are addressed.

An outbreak of ertapenem-resistant, carbapenemase-negative and porin-deficient ESBL-producing Klebsiella pneumoniae complex

Introduction

Carbapenem-resistant Klebsiella pneumoniae is an emerging healthcare-associated pathogen with dynamic molecular epidemiology. This study presents a retrospective analysis of the distribution and antibiotic resistance patterns of ertapenem-resistant ESBL-producing K. pneumoniae strains recovered during an outbreak from 2012 to 2014 in a Croatian University hospital.

Methods

We aimed to estimate genetic relatedness of clinical isolates and underlying mechanisms that conferred the ertapenem-resistant phenotype.

Results

Expression analysis of genes involved in the antibiotic resistance showed reduced expression of major non-selective porin channel OmpK35. Reduced expression of OmpK36 porin channel in isolates resistant to at least one more carbapenem, apart from the ertapenem, was found to a lesser degree. Pulsed-field gel electrophoresis analysis of genomic DNA revealed that almost all isolates belonged to the same genetic clone.

Conclusions

Caution regarding ertapenem-resistant, carbapenemase-negative porin-deficient mutants of K. pneumoniae is required as they are widespread, and under selective pressure this could result in a local clonal outbreak.

The role of antimicrobial stewardship in preventing KPC-producing Klebsiella pneumoniae

Antimicrobial stewardship programmes are widely considered to be a core component of the response to the antimicrobial resistance threat. However, a positive impact of these interventions in terms of microbiological outcomes remains difficult to demonstrate, especially when focusing on specific resistant phenotypes. The first part of this review aims to explore the complex relationship between antibiotic exposure and resistance development in KPC-producing Klebsiella pneumoniae. In the second part we aim to summarize published examples of antimicrobial stewardship interventions intended to impact on the epidemiology of KPC-producing K. pneumoniae. For this purpose, a literature search was performed and seven studies were included in the review. Both restrictive and non-restrictive interventions were associated with an overall reduction in antibiotic consumption, and a decrease in carbapenem resistance rates was observed in five studies. The overall quality of the evidence was low, mainly due to the poor reporting of microbiological outcomes, lack of a control group and suboptimal study design. Although the link between antibiotic use and resistance development is supported by strong evidence, demonstrating the impact of antimicrobial stewardship interventions on microbiological outcomes remains difficult. Studies with adequate design and appropriate outcome measures are needed to further promote antimicrobial stewardship and elucidate which interventions are more successful for controlling the spread of KPC-producing K. pneumoniae.

β-Lapachone Increases Survival of Septic Mice by Regulating Inflammatory and Oxidative Response

Sepsis is characterized by a dysregulated immune response to infection characterized by an early hyperinflammatory and oxidative response followed by a subsequent immunosuppression phase. Although there have been some advances in the treatment of sepsis, mortality rates remain high, urging for the search of new therapies. β-Lapachone (β-Lap) is a natural compound obtained from Tabebuia avellanedae Lorentz ex Griseb. with several pharmacological properties including bactericidal, anti-inflammatory, and antioxidant activity. Thus, the aim of this study was to evaluate the effects of β-Lap in a mouse sepsis model. To this, we tested two therapeutic protocols in mice submitted to cecal ligation and puncture- (CLP-) induced sepsis. First, we found that in pretreated animals, β-Lap reduced the systemic inflammatory response and improved bacterial clearance and mouse survival. Moreover, β-Lap also decreased lipid peroxidation and increased the total antioxidant capacity in the serum and peritoneal cavity of septic animals. In the model of severe sepsis, the posttreatment with β-Lap was able to increase the survival of animals and maintain the antioxidant defense function. In conclusion, the β-Lap was able to increase the survival of septic animals by a mechanism involving immunomodulatory and antioxidant protective effects.

Management of infections caused by WHO critical priority Gram-negative pathogens in Arab countries of the Middle East: a consensus paper

Antimicrobial resistance is an important global issue that impacts the efficacy of established antimicrobial therapy. This is true globally and within the Arab countries of the Middle East, where a range of key Gram-negative pathogens pose challenges to effective therapy. There is a need to establish effective treatment recommendations for this region given specific challenges to antimicrobial therapy, including variations in the availability of antimicrobials, infrastructure and specialist expertise. This consensus provides regional recommendations for the first-line treatment of hospitalized patients with serious infections caused by World Health Organization critical priority Gram-negative pathogens Acinetobacter baumannii and Pseudomonas aeruginosa resistant to carbapenems, and Enterobacteriaceae resistant to carbapenems and third-generation cephalosporins. A working group comprising experts in infectious disease across the region was assembled to review contemporary literature and provide additional consensus on the treatment of key pathogens. Detailed therapeutic recommendations are formulated for these pathogens with a focus on bacteraemia, nosocomial pneumonia, urinary tract infections, skin and soft tissue infections, and intra-abdominal infections. First-line treatment options are provided, along with alternative agents that may be used where variations in antimicrobial availability exist or where local preferences and resistance patterns should be considered. These recommendations take into consideration the diverse social and healthcare structures of the Arab countries of the Middle East, meeting a need that is not filled by international guidelines. There is a need for these recommendations to be updated continually to reflect changes in antimicrobial resistance in the region, as well as drug availability and emerging data from clinical trials.

Choice of therapeutic interventions and outcomes for the treatment of infections caused by multidrug-resistant gram-negative pathogens: a systematic review

Background

Antimicrobial resistance is an increasingly serious threat to public health, and the increased occurrence of multidrug-resistant (MDR) bacteria is a concern in both high-income and low- and middle-income countries. The purpose of this systematic review was to identify and critically appraise current antimicrobial treatment options for infections with MDR Gram-negative bacteria.

Methods

A literature search for treatment of MDR extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, A. baumannii, and P. aeruginosa was conducted in MEDLINE in January 2019. Relevant studies published in English, German, and French that evaluated clinical success, microbiological success, and 30-day mortality outcomes were included. The population of interest was adult patients.

Results

Of 672 studies, 43 met the inclusion criteria. Carbapenems are the most common antibiotics used for the treatment of ESBL-producing Enterobacteriaceae. The clinical and microbiological success was similar for group 1 carbapenems (imipenem, meropenem, or doripenem), group 2 carbapenems (ertapenem), and non-carbapenem antibiotics. Mortality data were contradictory for group 1 carbapenems compared to group 2 carbapenems. The most common treatment option for A. baumannii and P. aeruginosa infections was intravenous colistin, regardless of infection site. Clinical success and mortality were similar in A. baumannii infections treated with colistin combination therapy vs. colistin monotherapy, whereas heterogeneous results were found with respect to microbiological success. Monotherapy and colistin combination therapy were used against P. aeruginosa with clinical and microbiological success (70–100%) depending on the infection site and severity, and the antibiotic used. Ceftazidime-avibactam therapy for ESBL-producing Enterobacteriaceae and P. aeruginosa showed good clinical success in one study.

Conclusion

We did not find robust evidence for antibiotic treatment of any infection with MDR Gram-negative bacteria, including ESBL-producing Enterobacteriaceae, A. baumannii, and P. aeruginosa, that would lead to a firm recommendation for one specific antibiotic over another or for monotherapy over combination therapy. The choice of antibiotic treatment should be based on susceptibility testing balancing the expected clinical success rate against the risk of development of antibiotic resistance and the risk of severe side effects.

Treatment of urinary tract infections in the era of antimicrobial resistance and new antimicrobial agents

Urinary tract infections (UTIs) caused by antibiotic-resistant Gram-negative bacteria are a growing concern due to limited treatment options. Knowledge of the common uropathogens in addition to local susceptibility patterns is essential in determining appropriate empiric antibiotic therapy of UTIs. The recommended first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females is a 5-day course of nitrofurantoin, a 3-g single dose of fosfomycin tromethamine, or a 5-day course of pivmecillinam. High rates of resistance for trimethoprim-sulfamethoxazole and ciprofloxacin preclude their use as empiric treatment of UTIs in several communities, particularly if patients who were recently exposed to them or in patients who are at risk of infections with extended-spectrum β-lactamases (ESBLs)-producing Enterobacteriales. Second-line options include oral cephalosporins such as cephalexin or cefixime, fluoroquinolones and β-lactams, such as amoxicillin-clavulanate. Current treatment options for UTIs due to AmpC- β -lactamase-producing Enterobacteriales include nitrofurantoin, fosfomycin, pivmecillinam, fluoroquinolones, cefepime, piperacillin-tazobactam and carbapenems. Treatment oral options for UTIs due to ESBLs-E coli include nitrofurantoin, fosfomycin, pivmecillinam, amoxicillin-clavulanate, finafloxacin, and sitafloxacin while pivmecillinam, fosfomycin, finafloxacin, and sitafloxacin are treatment oral options for ESBLs- Klebsiella pneumoniae. Parenteral treatment options for UTIs due to ESBLs-producing Enterobacteriales include piperacillin-tazobactam (for ESBL-E coli only), carbapenems including meropenem/vaborbactam, imipenem/cilastatin-relebactam, and sulopenem, ceftazidime-avibactam, ceftolozane-tazobactam, aminoglycosides including plazomicin, cefiderocol, fosfomycin, sitafloxacin, and finafloxacin. Ceftazidime-avibactam, meropenem/vaborbactam, imipenem/cilastatin-relebactam, colistin, fosfomycin, aztreonam and ceftazidime-avibactam, aztreonam and amoxicillin-clavulanate, aminoglycosides including plazomicin, cefiderocol, tigecycline are treatment options for UTIs caused by carbapenem-resistant Enterobacteriales (CRE). Treatment options for UTIs caused by multidrug resistant (MDR)-Pseudomonas spp. include fluoroquinolones, ceftazidime, cefepime, piperacillin-tazobactam, carbapenems including imipenem-cilastatin/relebactam, meropenem, and fosfomycin, ceftolozane-tazobactam, ceftazidime-avibactam, aminoglycosides including plazomicin, aztreonam and ceftazidime-avibactam, cefiderocol, and colistin. It is important to use the new antimicrobials wisely for treatment of UTIs caused by MDR-organisms to avoid resistance development.

Current options for the treatment of infections due to extended-spectrum beta-lactamase-producing Enterobacteriaceae in different groups of patients

BACKGROUND

Extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) are a frequent cause of invasive infections worldwide. Carbapenems are nowadays the most used drugs to treat these infections. However, due to the increasing rates of resistance to these antimicrobials, carbapenem-sparing alternatives are being investigated.

OBJECTIVES AND SOURCES

The aim of this narrative literature review is to summarize the published information on the currently available antibiotics for the treatment of ESBL-E infections, providing specific information on three subgroups of patients: Group 1, patients with severe infections or infections from high-risk sources or in severely immunocompromised patients; Group 2, patients with non-severe infections from intermediate-risk source; and Group 3, patients with non-severe urinary tract infection.

CONTENT AND IMPLICATIONS

For patients in Group 1, the current data would support the use of carbapenems. For milder infections, however, particularly urinary tract infections, other non-carbapenem antibiotics can be considered in selected cases, including beta-lactam/beta-lactam inhibitor combinations, cephamycins, temocillin and aminoglycosides. While specific studies should be performed in these situations, individualized decisions may be taken in order to avoid overuse of carbapenems.

Monitoring the antimicrobial susceptibility of Gram-negative organisms involved in intraabdominal and urinary tract infections recovered during the SMART study (Spain, 2016 and 2017)

OBJECTIVE

Continuous antimicrobial resistance surveillance is recommended by Public Health authorities. We up-dated data from the SMART (Study for Monitoring Antimicrobial Resistance Trends) surveillance study in Spain.

METHODS

The antimicrobial susceptibility data and extended-spectrum beta-lactamase (ESBL) production in isolates recovered from intra-abdominal (IAI) (n=1,429) and urinary tract (UTI) (n=937) infections during the 2016- 2017 SMART study in 10 Spanish hospitals were analysed.

RESULTS

Escherichia coli was the most frequently microorganism isolated (48.3% and 53.7%) followed by Klebsiella spp. (11.5% and 21.9%) in IAIs and UTIs, respectively. Figures for Pseudomonas aeruginosa were 9.0% and 6.1%, being more frequently recovered from patients with nosocomial infections. Overall, 9.9% (IAI) and 14.0% (UTI) of E. coli, Klebsiella spp. and Proteus mirabilis isolates were ESBL-producers, being Klebsiella pneumoniae (34.5%) from UTI of nosocomial origin the most frequent. ESBL-producers were higher in patients >60 years in both IAIs and UTIs. As in previous years, amikacin (96.3%-100% susceptibility), ertapenem (84.2%-100%) and imipenem (70.3%- 100%) were the most active antimicrobials tested among Enterobacterales species. The activity of amoxicillin-clavulanic, piperacillin-tazobactam, and ciprofloxacin susceptibility was lower, particularly among ESBL-producers. Ertapenem susceptibility (88.9%-100%) was retained in ESBL-E. coli isolates that were resistant to these antimicrobials but decreased (28.6%-100%) in similar isolates of K. pneumoniae.

CONCLUSIONS

Continuous antimicrobial resistance surveillance from the SMART study reveals overall maintenance of ESBL-producers in Spain, although with higher presence in isolates from UTIs than from IAIs. Moreover, ertapenem activity was high in E. coli irrespective of ESBL production but decreased in K. pneumoniae, particularly among ESBL-producers.

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.

Management of infections caused by extended-spectrum β-lactamase-producing Enterobacteriaceae: current evidence and future prospects

INTRODUCTION

The spread of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae has become a major public health threat worldwide. Area covered: A thorough systematic literature review describing the current evidence and future prospects of therapeutic options for infections caused by ESBL-producing Enterobacteriaceae. Expert commentary: The methods of detecting ESBLs have been evolving. The Clinical and Laboratory Standards Institute and the European Committee on Antimicrobial Susceptibility Testing lowered the MIC breakpoints of cephalosporins against ESBL-producing Enterobacteriaceae in 2010. Phenotypic testing for ESBLs is no longer recommended. Instead, the selection of appropriate antimicrobial agents largely depends on the report of minimum inhibitory concentrations (MICs). To date, therapeutic options for these multidrug-resistant organisms remain limited. The clinical efficacy of piperacillin/tazobactam and cefepime on in vitro-susceptible ESBL-producing Enterobacteriaceae remains a concern. Many studies found an in vitro-in vivo discordance based on current breakpoints. Carbapenems are the most reliable antibiotics for severe infections caused by ESBL-producing Enterobacteriaceae. However, their overuse has led to a serious problem of increasing drug resistance. Recently, ceftolozane/tazobactam and ceftazidime/avibactam have been approved for the treatment of complicated urinary tract infections and complicated intra-abdominal infections. The introduction of these new β-lactam/β-lactamase inhibitor combinations offers new carbapenem-sparing options for the treatment of ESBL infections.