Impact of empirical treatment in extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella spp. bacteremia. A multicentric cohort study

Carbapenem-sparing beta-lactam/beta-lactamase inhibitors versus carbapenems for bloodstream infections caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae: a systematic review and meta-analysis

OBJECTIVES

Bloodstream infections (BSIs) caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) have become a worldwide public health threat, and beta-lactam/beta-lactamase inhibitor combinations (BLBLIs) are considered as one reliable carbapenem-sparing antibiotic. However, it is still controversial whether BLBLIs are truly noninferior to carbapenems. Therefore, we conducted this meta-analysis to compare the efficacy of BLBLIs with carbapenems for ESBL-PE BSIs.

METHODS

A systematic search of PubMed, Cochrane Library, and Embase was conducted until December 2021 to enroll studies comparing BLBLIs with carbapenems for ESBL-PE BSIs. A subgroup analysis was performed based on the choice of therapy (empirical, definitive, and mixed therapy). The protocol was registered in the International Prospective Register of Systematic Reviews (#CRD42022316011).

RESULTS

A total of 2786 patients from one randomized clinical trial and 25 cohorts were included. There was no statistically significant difference between BLBLIs and carbapenems groups in therapeutical response (odds ratio [OR] = 1.19, P = 0.45) and mortality (OR = 1.06, P = 0.68). Furthermore, although the statistical difference was also not found in the subgroup analysis, BLBLIs performed better in definitive therapy than empirical therapy than carbapenems, with a numerically higher therapeutical response (OR = 1.42 vs 0.89) and a mildly lower mortality (OR = 0.85 vs 1.14).

CONCLUSION

BLBLIs were noninferior to carbapenems for ESBL-PE BSIs, especially in definitive therapy. BLBLIs may be a valid alternative to spare the use of carbapenems.

Retrospective analysis of bacteraemia due to extended-spectrum beta-lactamase-producing Enterobacterales: the challenge of healthcare-associated infections

Objectives

Healthcare-associated bacteraemia is defined as bacteraemia diagnosed ≤48 h after hospital admission in patients recently exposed to healthcare procedures or settings. It differs from hospital-acquired bacteraemia, which is diagnosed >48 h after hospital admission. Healthcare-associated bacteraemia is reported increasingly, often due to resistant pathogens including extended-spectrum beta-lactamase (ESBL) producers, representing a challenge to empirical treatment. This study aimed to assess the appropriateness of empirical treatment for ESBL bacteraemia at the authors' centre, to perform a descriptive analysis according to the mode of infection acquisition (community-acquired, healthcare-associated, hospital-acquired), and to assess the risk factors for mortality.

Methods

A retrospective study on patients with ESBL bacteraemia was undertaken.

Results

In total, 129 consecutive cases of bacteraemia due to ESBL producers were included in this study. Compared with community- and hospital-acquired bacteraemia, healthcare-associated bacteraemia affected older patients (P=0.001) and patients with higher Charlson Comorbidity Index scores (P=0.007), and was more frequently associated with piperacillin-tazobactam resistance (P=0.025) and multi-drug resistance (P=0.026). Overall, ineffective empirical treatment was common (42%). Factors associated with 30-day mortality were septic shock [odds ratio (OR) 7.096, 95% confidence interval (CI) 2.58-24.58], high Pitt score (OR 6.636, 95% CI 1.71-23.62) and unknown source of bacteraemia (OR 19.28, 95% CI 2.80-30.70).

Conclusions

Antimicrobial stewardship interventions focusing on both in-hospital and community settings are advocated to better manage healthcare-associated infections due to ESBL producers.

Initial empirical antibiotics of non-carbapenems for ESBL-producing E. coli and K. pneumoniae bacteremia in children: a retrospective medical record review

BACKGROUND

The efficacy of non-carbapenems as an empirical antibiotic for extended-spectrum β-lactamases (ESBL)-producing Escherichia coli and Klebsiella pneumoniae bacteremia in children remains controversial. We compared clinical and microbial outcomes according to the types of empirical antibiotics for treating pediatric patients with ESBL-producing E. coli and K. pneumoniae bacteremia.

METHODS

Data from pediatric patients aged ≤ 18 years who were hospitalized with monomicrobial ESBL-producing E. coli or K. pneumoniae bacteremia at Asan Medical Center Children's Hospital, Seoul, Korea between January 2014 and May 2019 were analyzed retrospectively. The impact of empirical therapy was assessed as 30-day all-cause mortality and 2-day microbiological outcomes evaluated by the sterility of blood cultures collected on day 2 after empirical antibiotic administration. Logistic regression analysis was used to control for the effects of confounding variables.

RESULTS

A total of 53 patients with bacteremia caused by ESBL-producing E. coli (n = 29) and K. pneumoniae (n = 24) were included in this study; the median age was 3.6 years, and all had underlying comorbidities. As empirical antibiotics, 27 patients were treated with meropenem, and non-carbapenem agents were administered to 26 patients; 84.6% (22/26) were converted to carbapenem antibiotics as the definitive antibiotic by day 2 after empirical antibiotic administration. Overall, the 30-day all-cause mortality of ESBL-producing E. coli and K. pneumoniae bacteremia was 17.0% (9/53). After adjustment, there was no statistically significant association of use of a non-carbapenem agent as an empirical antibiotic with microbiological failure on day 2 and 30-day all-cause mortality [adjusted odds ratio (OR) 1.0; 95% confidence interval (CI) 0.22-4.88, and adjusted OR 0.1; 95% CI 0.01-1.56].

CONCLUSIONS

The empirical use of non-carbapenems might not be a risk factor for mortality and early microbiological outcomes in pediatric patients with ESBL-producing E. coli and K. pneumoniae BSI if early transition to appropriate antimicrobial therapy was possible.

Effects of Inappropriate Administration of Empirical Antibiotics on Mortality in Adults With Bacteraemia: Systematic Review and Meta-Analysis

Introduction

Bloodstream infections are associated with high mortality rates and contribute substantially to healthcare costs, but a consensus on the prognostic benefits of appropriate empirical antimicrobial therapy (EAT) for bacteraemia is lacking.

Methods

We performed a systematic search of the PubMed, Cochrane Library, and Embase databases through July 2021. Studies comparing the mortality rates of patients receiving appropriate and inappropriate EAT were considered eligible. The quality of the included studies was assessed using Joanna Briggs Institute checklists.

Results

We ultimately assessed 198 studies of 89,962 total patients. The pooled odds ratio (OR) for the prognostic impacts of inappropriate EAT was 2.06 (P < 0.001), and the funnel plot was symmetrically distributed. Among subgroups without between-study heterogeneity (I² = 0%), those of patients with severe sepsis and septic shock (OR, 2.14), Pitt bacteraemia scores of ≥4 (OR, 1.88), cirrhosis (OR, 2.56), older age (OR, 1.78), and community-onset/acquired Enterobacteriaceae bacteraemia infection (OR, 2.53) indicated a significant effect of inappropriate EAT on mortality. The pooled adjusted OR of 125 studies using multivariable analyses for the effects of inappropriate EAT on mortality was 2.02 (P < 0.001), and the subgroups with low heterogeneity (I² < 25%) exhibiting significant effects of inappropriate EAT were those of patients with vascular catheter infections (adjusted OR, 2.40), pneumonia (adjusted OR, 2.72), or Enterobacteriaceae bacteraemia (adjusted OR, 4.35). Notably, the pooled univariable and multivariable analyses were consistent in revealing the negligible impacts of inappropriate EAT on the subgroups of patients with urinary tract infections and Enterobacter bacteraemia.

Conclusion

Although the current evidence is insufficient to demonstrate the benefits of prompt EAT in specific bacteraemic populations, we indicated that inappropriate EAT is associated with unfavorable mortality outcomes overall and in numerous subgroups. Prospective studies designed to test these specific populations are needed to ensure reliable conclusions.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42021270274.

Activity of temocillin against third-generation cephalosporin-resistant Escherichia coli and Klebsiella pneumoniae bloodstream isolates from a clinical trial

Background

Extended spectrum β-lactamase (ESBL) and AmpC-producing Gram-negative bacilli contribute significantly to the antimicrobial resistance (AMR) burden worldwide. Temocillin is an intravenous semisynthetic antibiotic that is stable to hydrolysis by ESBLs and AmpC. Temocillin may be a treatment option for serious infections due to these organisms.

Methods

Third-generation cephalosporin-resistant Escherichia coli and Klebsiella pneumoniae isolates from the MERINO trial were collected. The majority originated from the urinary tract. Isolates had previously undergone whole genome sequencing (WGS) to identify antimicrobial resistance genes. Temocillin minimum inhibitory concentration (MIC) values were determined by broth microdilution (BMD) with a concentration range of 2 to 128 mg/L. A recent EUCAST guideline has recommended clinical breakpoints for urinary E. coli, Klebsiella spp. (except K. aerogenes) and Proteus mirabilis (resistant &gt;16 mg/L).

Results

317 index bloodstream isolates (275 E. coli and 42 K. pneumoniae) were used. The frequency of β-lactamases among isolates was: CTX-M-15 (56%), OXA-1 (31%), CTX-M-27 (14%), CTX-M-14 (12%) and CMY-2 (8%). Overall, 95% of isolates were susceptible, increased exposure according to EUCAST clinical breakpoints v11.0. Summary MIC values were obtained: MIC50 was 8 mg/L and MIC90 was16 mg/L (range ≤2 to ≥128 mg/L) and did not differ markedly between species. Higher MIC values were seen among isolates that produced more than one β-lactamase but this did not appear to be specific to a single β-lactamase.

Conclusions

Temocillin demonstrated favourable in vitro activity against ceftriaxone-resistant Enterobacterales bloodstream isolates and may be a suitable agent to be trialled for treatment of serious infections due to these organisms.

Ceftolozane-tazobactam versus meropenem for definitive treatment of bloodstream infection due to extended-spectrum beta-lactamase (ESBL) and AmpC-producing Enterobacterales ("MERINO-3"): study protocol for a multicentre, open-label randomised non-inferiority trial

BACKGROUND

Extended-spectrum beta-lactamase (ESBL) and AmpC-producing Enterobacterales are common causes of bloodstream infection. ESBL-producing bacteria are typically resistant to third-generation cephalosporins and result in a sizeable economic and public health burden. AmpC-producing Enterobacterales may develop third-generation cephalosporin resistance through enzyme hyper-expression. In no observational study has the outcome of treatment of these infections been surpassed by carbapenems. Widespread use of carbapenems may drive the development of carbapenem-resistant Gram-negative bacilli.

METHODS

This study will use a multicentre, parallel group open-label non-inferiority trial design comparing ceftolozane-tazobactam and meropenem in adult patients with bloodstream infection caused by ESBL or AmpC-producing Enterobacterales. Trial recruitment will occur in up to 40 sites in six countries (Australia, Singapore, Italy, Spain, Saudi Arabia and Lebanon). The sample size is determined by a predefined quantity of ceftolozane-tazobactam to be supplied by Merck, Sharpe and Dohme (MSD). We anticipate that a trial with 600 patients contributing to the primary outcome analysis would have 80% power to declare non-inferiority with a 5% non-inferiority margin, assuming a 30-day mortality of 5% in both randomised groups. Once randomised, definitive treatment will be for a minimum of 5 days and a maximum of 14 days with the total duration determined by treating clinicians. Data describing demographic information, risk factors, concomitant antibiotics, illness scores, microbiology, multidrug-resistant organism screening, discharge and mortality will be collected.

DISCUSSION

Participants will have bloodstream infection due to third-generation cephalosporin non-susceptible E. coli and Klebsiella spp. or Enterobacter spp., Citrobacter freundii, Morganella morganii, Providencia spp. or Serratia marcescens. They will be randomised 1:1 to ceftolozane-tazobactam 3 g versus meropenem 1 g, both every 8 h. Secondary outcomes will be a comparison of 14-day all-cause mortality, clinical and microbiological success at day 5, functional bacteraemia score, microbiological relapse, new bloodstream infection, length of hospital stay, serious adverse events, C. difficile infection, multidrug-resistant organism colonisation. The estimated trial completion date is December 2024.

TRIAL REGISTRATION

The MERINO-3 trial is registered under the US National Institute of Health ClinicalTrials.gov register, reference number: NCT04238390 . Registered on 23 January 2020.

Population Pharmacokinetics of Piperacillin in Non-Critically Ill Patients with Bacteremia Caused by Enterobacteriaceae

This study analyzes the pharmacokinetic variability of piperacillin in non-critically ill patients with Enterobacteriaceae bloodstream infections (EBSI) and explores predicted clinical outcomes and piperacillin-related neurotoxicity under different renal conditions. Hospitalized, non-critically ill patients treated with piperacillin–tazobactam for EBSI were included. Four serum samples per patient were collected and analyzed. A population pharmacokinetic model was developed using the Pmetrics package for R. Monte Carlo simulations of various dosage regimens of 4 g piperacillin, administered q8 h or q12 h by short (0.5 h) or long (4 h) infusion, following the different glomerular filtration rate (GFR) categories used to classify chronic kidney disease (Kidney Disease: Improving Global Outcomes, KDIGO) to determine the probability of target attainment (PTA) using a free drug concentrations above the minimal inhibitory concentration (fT > MIC) of 50% for efficacy and targets for piperacillin-associated neurotoxicity. Twenty-seven patients (102 samples) were included. Extended piperacillin infusions reached a PTA > 90% (50%fT > MIC) within the susceptibility range, although a loading dose did not greatly improve the expected outcome. Long infusions reduced the expected toxicity in patients with severe renal impairment. The study supports the use of extended infusions of piperacillin in non-critically ill patients with EBSI. No benefits of a loading dose were expected in our population. Finally, extended infusions may reduce the risk of toxicity in patients with severe renal impairment.

Efficacy of β-lactam/β-lactamase inhibitors to treat extended-spectrum beta-lactamase-producing Enterobacterales bacteremia secondary to urinary tract infection in kidney transplant recipients (INCREMENT-SOT Project)

BACKGROUND

Whether active therapy with β-lactam/β-lactamase inhibitors (BLBLI) is as affective as carbapenems for extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) bloodstream infection (BSI) secondary to urinary tract infection (UTI) in kidney transplant recipients (KTRs) remains unclear.

METHODS

We retrospectively evaluated 306 KTR admitted to 30 centers from January 2014 to October 2016. Therapeutic failure (lack of cure or clinical improvement and/or death from any cause) at days 7 and 30 from ESBL-E BSI onset was the primary and secondary study outcomes, respectively.

RESULTS

Therapeutic failure at days 7 and 30 occurred in 8.2% (25/306) and 13.4% (41/306) of patients. Hospital-acquired BSI (adjusted OR [aOR]: 4.10; 95% confidence interval [CI]: 1.50-11.20) and Pitt score (aOR: 1.47; 95% CI: 1.21-1.77) were independently associated with therapeutic failure at day 7. Age-adjusted Charlson Index (aOR: 1.25; 95% CI: 1.05-1.48), Pitt score (aOR: 1.72; 95% CI: 1.35-2.17), and lymphocyte count ≤500 cells/μL at presentation (aOR: 3.16; 95% CI: 1.42-7.06) predicted therapeutic failure at day 30. Carbapenem monotherapy (68.6%, primarily meropenem) was the most frequent active therapy, followed by BLBLI monotherapy (10.8%, mostly piperacillin-tazobactam). Propensity score (PS)-adjusted models revealed no significant impact of the choice of active therapy (carbapenem-containing vs any other regimen, BLBLI- vs carbapenem-based monotherapy) within the first 72 hours on any of the study outcomes.

CONCLUSIONS

Our data suggest that active therapy based on BLBLI may be as effective as carbapenem-containing regimens for ESBL-E BSI secondary to UTI in the specific population of KTR. Potential residual confounding and unpowered sample size cannot be excluded (ClinicalTrials.gov identifier: NCT02852902).

The Association Between Empirical Antibiotic Treatment and Mortality in Severe Infections Caused by Carbapenem-resistant Gram-negative Bacteria: A Prospective Study

Background

Empirical colistin should be avoided. We aimed to evaluate the association between covering empirical antibiotics (EAT) and mortality for infections caused by carbapenem-resistant gram-negative bacteria (CRGNB).

Methods

This was a secondary analysis of a randomized controlled trial, including adults with bloodstream infections, pneumonia, or urosepsis caused by CRGNB. All patients received EAT followed by covering targeted therapy. The exposure variable was covering EAT in the first 48 hours. The outcome was 28-day mortality. We adjusted the analyses by multivariable regression analysis and propensity score matching.

Results

The study included 406 inpatients with severe CRGNB infections, mostly Acinetobacter baumannii (312/406 [77%]). Covering EAT was given to 209 (51.5%) patients, mostly colistin (n = 200). Patients receiving noncovering EAT were older, more frequently unconscious and dependent, carrying catheters, and mechanically ventilated with pneumonia. Mortality was 84 of 197 (42.6%) with noncovering vs 96 of 209 (45.9%) with covering EAT (P = .504). Covering EAT was not associated with survival in the adjusted analysis; rather, there was a weak association with mortality (odds ratio [OR], 1.37; 95% confidence interval [CI], 1.02-1.84). Results were similar for colistin monotherapy and colistin-carbapenem combination EAT. In the propensity score-matched cohort (n = 338) covering antibiotics were not significantly associated with mortality (OR, 1.42; 95% CI, .91-2.22). Similar results were obtained in an analysis of 14-day mortality.

Conclusions

Empirical use of colistin before pathogen identification, with or without a carbapenem, was not associated with survival following severe infections caused by CRGNBs, mainly A. baumannii.

Clinical effectiveness of carbapenems versus alternative antibiotics for treating ESBL-producing Enterobacteriaceae bacteraemia: a systematic review and meta-analysis

Objectives

The widespread administration of carbapenems to patients with ESBL-producing Enterobacteriaceae bacteraemia (ESBL-B) has accelerated the emergence of carbapenem-resistant Enterobacteriaceae. This study aimed to systematically review recently published data to evaluate the clinical effectiveness of carbapenems, compared with other antibiotics, in the treatment of ESBL-B.

Methods

We searched the Ovid-Medline, Ovid-Embase, Cochrane Library and five Korean local databases until January 2016. We selected studies that reported overall mortality in patients with ESBL-B who had been treated with carbapenems and alternatives. Overall mortality was assessed as the primary outcome and sepsis-related mortality and adverse events were analysed as secondary outcomes.

Results

Thirty-five publications fulfilled the inclusion criteria. Regarding empirical therapy, there were no significant differences between the groups that received carbapenems and those that received non-carbapenems in relation to overall mortality. Regarding definitive therapy, overall mortality was lower for patients administered carbapenems compared with those administered non-carbapenems [risk ratio (RR) 0.78, 95% CI 0.61-0.98], non-β-lactam/β-lactamase inhibitor combinations (non-BL/BLI) (RR 0.71, 95% CI 0.56-0.90) and cephalosporins (RR 0.56, 95% CI 0.42-0.74). There were no differences between the carbapenems and the other antibiotics, namely BL/BLIs, quinolones and aminoglycosides.

Conclusions

This meta-analysis showed that BL/BLIs may be promising alternative antibiotics for definitive therapy in patients with ESBL-B. However, the lack of robust data derived from randomized controlled trials limits the conclusions and inferences from the pooled data.

Increased community-acquired upper urinary tract infections caused by extended-spectrum beta-lactamase-producing Escherichia coli in children and the efficacy of flomoxef and cefmetazole

Background

Urinary tract infections caused by extended-spectrum beta-lactamase-producing bacteria are increasing worldwide. At our hospital, the number of pediatric patients hospitalized because of an upper urinary tract infection has dramatically increased since 2016. In total, 60.5% of urinary tract infections are caused by extended-spectrum beta-lactamase-producing Escherichia coli. Such a high prevalence of extended-spectrum beta-lactamase-producing E. coli has not been detected previously in Japan. Therefore, we evaluated the clinical and bacteriologic characteristics and efficacy of antibiotics against upper urinary tract infections caused by E. coli in children.

Methods

This retrospective study surveyed 152 patients who were hospitalized in the pediatric department of Shimane Prefectural Central Hospital because of upper urinary tract infections caused by E. coli. Medical records were reviewed to examine patient characteristics. O antigens, antibiotic susceptibility, gene typing, and pulse-field gel electrophoresis were studied at the Shimane Prefectural Institute of Public Health and Environmental Science.

Results

Urine sample analyses showed extended-spectrum beta-lactamase types such as CTX-M-9 and plural virulence genes. We changed the primary antibiotic treatment to flomoxef or cefmetazole to treat upper urinary tract infections caused by Gram-negative bacilli. After changing treatment, the time to fever alleviation was significantly shortened.

Conclusion

Extended-spectrum beta-lactamase-producing E. coli should be suspected in community-acquired upper urinary tract infections. Therefore, when treating patients, it is necessary to focus on antibiotic susceptibility and the prevalence of extended-spectrum beta-lactamase-producing bacteria found in each area. Flomoxef and cefmetazole are useful primary treatments for upper urinary tract infections caused by extended-spectrum beta-lactamase-producing E. coli.

Extended-Spectrum Beta-Lactamase-Producing Escherichia coli Meningitis and Cerebral Abscess in a Neonate: Therapeutic Challenge

We report a case of a 12-day-old term neonate with extended-spectrum beta-lactamase (ESBL) producing Escherichia coli (E. coli) meningitis and cerebral abscess. The patient received a 7-day course of antibiotics just few days prior to the infection. The incidence of infections from ESBL-producing E. coli is increasingly emerging. Antimicrobial agents must be vigilantly utilized to prevent the new highly resistant bacteria.

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

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

Prevalence of and risk factor for community-onset third-generation cephalosporin-resistant Escherichia coli bacteremia at a medical center in Taiwan

Background

Increased resistance to third-generation cephalosporin (3GC) is a serious concern for community-onset Escherichia coli infection because this resistance easily delays effective treatment. This study surveyed the current antimicrobial resistance pattern among E. coli isolates that cause community-onset bacteremia, with a special focus on the prevalence of and the risk factors for 3GC resistance, and determined factors for poor outcomes among patients with community-onset E. coli bacteremia.

Methods

This retrospective study was conducted at a tertiary-care teaching hospital in Taiwan. All adult patients with community-onset E. coli bacteremia between January 1, 2015, and December 31, 2015 were enrolled and were divided into two groups depending on whether the E. coli isolate was susceptible to 3GCs. Risk factors for 3GC resistance, 14-day all-cause mortality, and length of hospital stay were analyzed.

Results

The overall rate of 3GC resistance among E. coli isolates causing community-onset bacteremia was 19.7%, whereas it was 9.6% if only isolates causing community-acquired bacteremia were considered. Independent risk factors for 3GC-resistant community-onset E. coli bacteremia were hospitalization within the past 1 year (odds ratio: 2.4, 95% confidence interval: 1.6–3.7, P < 0.001), exposure to antibiotics within the past 15 days (2.6, 1.4–4.9, P = 0.002), residence in nursing home or long-term care facility (3.6, 1.0–12.3, P = 0.044), presence of underlying genitourinary disease (1.9, 1.2–2.9, P = 0.005), and presence of indwelling implantable intravenous port (2.2, 1.1–4.1, P = 0.021). 3GC resistance was independently associated with increased length of hospital stays (P < 0.001).

Conclusion

In this study, the prevalence of 3GC resistance was high among both patients with community-onset and those with community-acquired E. coli bacteremia. 3GC resistance is a strong independent risk factor for length of hospital stay. The effectiveness of empirical antibiotic treatment would partially explain the impact of 3GC resistance, but more evidence is needed. The choice of appropriate empirical antibiotics for community-onset E. coli bacteremia might impact outcomes in terms of the length of hospital stay and need to be individualized according to the patient-specific risk for acquiring drug-resistant pathogens.

A multicenter epidemiology study on the risk factors and clinical outcomes of nosocomial intra-abdominal infections in China: results from the Chinese Antimicrobial Resistance Surveillance of Nosocomial Infections (CARES) 2007-2016

Objective

This study aimed to determine the risk factors for intra-abdominal infections (IAIs), assess the clinical outcomes of IAIs, and investigate the spectrum and antimicrobial resistance of major pathogens causing IAIs.

Patients and methods

This prospective observational study enrolled patients from the Chinese Antimicrobial Resistance Surveillance of Nosocomial Infections (CARES) program between 2007 and 2016. Data on the clinicopathological factors and causative pathogens were collected. The results of antimicrobial susceptibility tests were interpreted according to the minimum inhibitory concentration (MIC) interpretive breakpoints recommended by the Clinical and Laboratory Standards Institute in 2017.

Results

A total of 2,756 patients were included. The 30-day all-cause mortality was 9.5% (262/2,756). Multivariable analysis showed that the following independent risk factors were associated with the 30-day mortality: age >60 years, pulmonary disease, tracheal cannula, infection occurring in intensive care unit (ICU), prior admission within 3 months, antibiotic use before infection, recent use of immunosuppressants, and multidrug-resistant organisms. In addition, 2,913 clinical isolates were collected. The Gram-negative and Gram-positive bacteria accounted for 70.8% and 29.2% of all isolates, respectively. The most common pathogens were Escherichia coli (33.4%), Klebsiella pneumoniae (10.8%), and Enterococcus faecium (10.7%). Pseudomonas aeruginosa and Acinetobacter baumannii were the most common non-Enterobacteriaceae Gram-negative pathogens. E. faecium, Enterococcus faecalis, and Staphylococcus aureus were the most common Gram-positive pathogens. E. coli, A. baumannii, and Enterobacter cloacae were more commonly found in ICU patients than in non-ICU patients. Overall, the antibiotics tested in the CARES exhibited diminished susceptibility to pathogens over the study period, especially extended spectrum β-lactamase producing isolates.

Conclusion

Considering the current data set and high-level resistance of intra-abdominal pathogens to various antibiotics, further monitoring of the epidemiology of IAIs and their susceptibility to antibiotics through the CARES is warranted.

Current antimicrobial susceptibility testing for beta-lactamase-producing Enterobacteriaceae in clinical settings

The worldwide prevalence of beta-lactamase-producing Enterobacteriaceae (BL-E) is increasing. Bacterial infections involving ESBLs can be more difficult to treat because of antibiotic resistance, as there are fewer effective antibiotics left to be used. Moreover, treatment failure is often observed. Thus, quick and accurate identification of β-lactamases is imperative to minimize it. This review article describes most commonly used phenotypic techniques and molecular methods for the detection of ESBLs, acquired AmpC β-lactamases, and carbapenemases produced by Enterobacteriaceae. Phenotypic detection tests remain useful and relevant in clinical laboratories while molecular diagnostic methods are less affordable, more technically demanding, and not standardized. Molecular methods could be used to speed up results of bacterial antibiotic resistance or to clarify the results of phenotypic β-lactamases confirmation tests.

Bloodstream infections in cancer patients. Risk factors associated with mortality

OBJECTIVE

The aim of this study was to evaluate the clinical characteristics and risk factors associated with mortality in cancer patients with bloodstream infections (BSI), analyzing multidrug resistant bacteria (MDR).

METHODS

We conducted a prospective observational study at a cancer referral center from August 2016 to July 2017, which included all BSI.

RESULTS

4220 patients were tested with blood cultures; 496 were included. Mean age was 48 years. In 299 patients with solid tumors, secondary BSI and Central Line-Associated BSI (CLABSI) were the most common (55.9% and 31.8%, respectively). In 197 hematologic patients, primary and mucosal barrier injury (MBI) BSI were the main type (38.6%). Gram-negative were the most frequent bacteria (72.8%), with Escherichia coli occupying the first place (n=210, 42.3%), 48% were Extended-Spectrum Beta-Lactamase (ESBL) producers, and 1.8% were resistant to carbapenems. Mortality at day 30, was 22%, but reached 70% when patients did not receive an appropriate antimicrobial treatment. Multivariate analysis showed that progression or relapse of the oncologic disease, inappropriate antimicrobial treatment, and having resistant bacteria were independently associated with 30-day mortality.

CONCLUSIONS

Emergence of MDR bacteria is an important healthcare problem worldwide. Patients with BSI, particularly those patients with MDR bacteria have a higher mortality risk.

Molecular Epidemiology of Klebsiella pneumoniae Strains Causing Bloodstream Infections in Adults

Molecular epidemiology of Klebsiella pneumoniae bacteremic strains allows for a better understanding of preventive and therapeutic strategies. Clinical and microbiological characteristics of 348 K. pneumoniae bacteremia cases (2007-2009) were retrospectively characterized by multilocus sequence typing and extended-spectrum beta-lactamases (ESBL) production. Overall, 223 (64.08%) cases were nosocomial (NA), 58 (16.67%) healthcare associated, and 67 (19.25%) community acquired. The main infection origins were urinary tract (16.6%, 50.0%, and 43.3%), biliary tract (10.8%, 24.2%, and 31.3%), and catheter-related infection (39.9%, 5.2%, and 0%). The 30-day mortality rate was around 20%. The rates of resistance were around 45% the highest being among NA cases, and ESBL production was detected in 7.2% of cases. A total of 161 different sequence types were grouped into 13 clonal sets by e-burst analysis. No relationship could be established between clonal sets and the origin of infection or the healthcare-related settings. The high genetic variability among the isolates suggests their intrapatient endogenous origin.

Extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae from urinary tract infections: Evolution of antimicrobial resistance and treatment options

BACKGROUND AND OBJECTIVES

A study of the susceptibility to antimicrobials of the extended spectrum beta-lactamase phenotypes (ESBL) in Escherichia coli and Klebsiella spp. was performed to discover the evolution of this type of resistance from urinary tract infections.

MATERIAL AND METHOD

A retrospective study was carried out between 2012 and 2016. Susceptibility to ciprofloxacin, tobramycin, cefoxitin, fosfomycin, nitrofurantoin, co-trimoxazole, and carbapenems was analyzed using MicroScan^® system.

RESULTS

A total of 95,399 samples were processed and 9,772 E. coli, 1,784 Klebsiella pneumoniae and 248 Klebsiella oxytoca were isolated. ESBL strains were more frequent in women, although they decreased during 2015 and 2016 (65.7-67.2%). The prevalence of K. pneumoniae ESBL increased annually (28.1% in 2016). The average prevalence of E. coli ESBL was 10.5% with few oscillations. Higher resistance occurred to ciprofloxacin and cotrimoxazole, 89.5 and 94.7% in 2015, respectively, and there was lesser resistance to imipenem. Fosfomycin and nitrofurantoin were very active on E. coli ESBL.

CONCLUSIONS

ESBL producing E. coli and K. pneumoniae were prevalent, especially the latter, with a significant resistance to ciprofloxacin and cotrimoxazole. Susceptibility to imipenem was high.

The impact of inoculum size on the activity of cefoperazone-sulbactam against multidrug resistant organisms

OBJECTIVES

This study aims to assess the in vitro activity of cefoperazone alone and different cefoperazone-sulbactam ratios against different inoculum sizes of multidrug resistant organisms.

METHODS

Minimum inhibitory concentrations (MICs) of cefoperazone, cefoperazone-sulbactam at fixed ratio of 1:1 and 2:1 against a normal inoculum size of 5 × 10⁵ CFU/ml and a high inoculum size of 5 × 10⁷ CFU/ml were measured.

RESULTS

Each 33 isolates of extended-spectrum β-lactamases (ESBL)-producing Escherichia coli, ESBL-producing Klebsiella pneumoniae, carbapenem-resistant E. coli, and carbapenem-resistant Pseudomonas aeruginosa and a total of 122 isolates of carbapenem-resistant Acinetobacter baumannii were collected. After the addition of sulbactam at a 1:1 ratio, most MIC₅₀ and MIC₉₀ values decreased. Cefoperazone-sulbactam at a 1:1 ratio had a higher susceptibility rate against ESBL-producing E. coli, carbapenem-resistant E. coli, and carbapenem-resistant A. baumannii than cefoperazone-sulbactam at a 2:1 ratio (all P < 0.05). For ESBL-producing E. coli, the susceptibility rate of cefoperazone-sulbactam at ratios of (1:1) and (2:1) decreased from 97.0 to 87.9% and 90.9 to 60.6%, for normal to high inoculum, respectively. For ESBL-producing K. pneumoniae, both susceptibility rate of cefoperazone-sulbactam at ratios of (1:1) and (2:1) decreased from 75.8%, and 63.6% at normal inoculum to 51.5% and 42.4% at high inoculum.

CONCLUSIONS

Cefoperazone-sulbactam at a 1:1 ratio has greater in vitro activity against most multidrug resistant organisms than cefoperazone-sulbactam at a 2:1 ratio. Such combinations were not influenced by the inoculum size of ESBL-producing E. coli and K. pneumoniae and could be a therapeutic option for treating severe infections.

Results of an early intervention programme for patients with bacteraemia: analysis of prognostic factors and mortality

Background

Bacteraemia is a common cause of morbidity and mortality in patients admitted to hospital. The aim of this study is to analyse the results of a two-year programme for the early optimisation of antibiotic treatment in patients admitted to the Costa del Sol Hospital (Marbella. Spain).

Methods

A prospective two-year cohort study was conducted, evaluating all episodes of bacteraemia at the Costa del Sol Hospital. Epidemiological and microbiological characteristics, any modification of the initial antibiotic treatment, prognostic risk stratification, early mortality related to the episode of bacteraemia, and mortality after the seventh day, were included in the analysis.

Results

Seven hundred seventy-three episodes of bacteraemia were treated, 61.6% males and 38.4% females. The mean age was 65.2 years. The condition was most commonly acquired in the community (41.4%). The bacteraemia was most frequently urological in nature (30.5%), and E coli was the microorganism most frequently isolated (31.6%). In 51.1% of the episodes, a modification was made to optimise the treatment. In the first week, 8.2% died from bacteraemia, and 4.5% had died when they were located. The highest rates of death were associated with older patients, nosocomial acquisition, no source, McCabe score rapidly fatal, Charlson index ≥3, Pitt index ≥3 and treatment remained unmodified.

Conclusion

The existence of bacteraemia control programmes and teams composed of clinicians who are experienced in the treatment of infectious diseases, can improve the disease outcome by enabling more severe episodes of bacteraemia to be recognised and their empirical treatment optimised.

Comparison Between Carbapenems and β-Lactam/β-Lactamase Inhibitors in the Treatment for Bloodstream Infections Caused by Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae: A Systematic Review and Meta-Analysis

Background

Carbapenems are widely used for the management of bloodstream infections (BSIs) caused by extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE). However, the wide use of carbapenems has been associated with carbapenem-resistant Enterobacteriaceae development.

Methods

We searched the PubMed and Scopus databases (last search date was on June 1, 2016) looking for studies that reported mortality in adult patients with ESBL-PE BSIs that were treated with carbapenems or β-lactam/β-lactamase inhibitors (BL/BLIs).

Results

Fourteen studies reported mortality data in adult patients with ESBL-PE BSI that were treated with carbapenems or BL/BLIs. Among them, 13 studies reported extractable data on empiric therapy, with no statistically significant difference in mortality of patients with ESBL-PE BSI that were treated empirically with carbapenems (22.1%; 121 of 547), compared with those that received empiric BL/BLIs (20.5%; 109 of 531; relative risk [RR], 1.05; 95% confidence interval [CI], 0.83–1.37; I² = 20.7%; P = .241). In addition, 7 studies reported data on definitive therapy. In total, 767 patients (79.3%) received carbapenems and 199 patients (20.6%) received BL/BLIs as definitive therapy, and there was again no statistically significant difference (RR, 0.62; 95% CI, 0.25–1.52; I² = 84.6%; P < .001). Regarding specific pathogens, the use of empiric BL/BLIs in patients with BSI due to ESBL-Escherichia coli was not associated with a statistically significant difference in mortality (RR, 1.014; 95% CI, 0.491–2.095; I² = 62.5%; P = .046), compared with the use of empiric carbapenems.

Conclusions

These data do not support the wide use of carbapenems as empiric therapy, and BL/BLIs might be effective agents for initial/empiric therapy for patients with BSI caused by likely ESBL-PE, and especially ESBL-E coli.

Specific Clinical Profile and Risk Factors for Mortality in General Surgery Patients with Infections by Multi-Drug-Resistant Gram-Negative Bacteria

BACKGROUND

The incidence of gram-negative multi-drug-resistant (MDR) infections is increasing worldwide. This study sought to determine the incidence, clinical profiles, risk factors, and mortality of these infections in general surgery patients.

PATIENTS AND METHODS

All general surgery patients with a clinical infection by gram-negative MDR bacteria were studied prospectively for a period of five years (2007-2011). Clinical, surgical, and microbiologic parameters were recorded, with a focus on the identification of risk factors for MDR infection and mortality.

RESULTS

Incidence of MDR infections increased (5.6% to 15.2%) during the study period; 106 patients were included, 69.8% presented nosocomial infections. Mean age was 65 ± 15 years, 61% male. Extended-spectrum β-lactamases (ESBL) Escherichia coli was the most frequent MDR bacteria. Surgical site infections and abscesses were the most common culture locations. The patients presented multiple pre-admission risk factors and invasive measures during hospitalization. Mortality was 15%, and related to older age (odds ratio [OR] 1.07), malnutrition (OR 13.5), chronic digestive conditions (OR 4.7), chronic obstructive pulmonary disease (OR 3.9), and surgical re-intervention (OR 9.2).

CONCLUSION

Multi-drug resistant infections in the surgical population are increasing. The most common clinical profile is a 65-year-old male, with previous comorbidities, who has undergone a surgical intervention, intensive care unit (ICU) admission, and invasive procedures and who has acquired the MDR infection in the nosocomial setting.

The Use of Bloodstream Infection Mortality to Measure the Impact of Antimicrobial Stewardship Interventions: Assessing the Evidence

This review sets out to evaluate the current evidence on the impact of inappropriate therapy on bloodstream infections (BSI) and associated mortality. Based on the premise that better prescribing practices should result in better patient outcomes, BSI mortality may be a useful metric to evaluate antimicrobial stewardship (AMS) interventions. A systematic search was performed in key medical databases to identify papers published in English between 2005 and 2015 that examined the association between inappropriate prescribing and BSI mortality in adult patients. Only studies that included BSIs caused by ESKAPE (Enterococcus faecium/faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species) organisms were included. Study quality was assessed using the GRADE criteria and results combined using a narrative synthesis. We included 46 studies. Inappropriate prescribing was associated with an overall increase in mortality in BSI. In BSI caused by resistant gram positive organisms, such as methicillin resistant S. aureus, inappropriate therapy resulted in up to a 3-fold increase in mortality. In BSI caused by gram negative (GN) resistant organisms a much greater impact ranging from 3 to 25 fold increase in the risk of mortality was observed. While the overall quality of the studies is limited by design and the variation in the definition of appropriate prescribing, there appears to be some evidence to suggest that inappropriate prescribing leads to increased mortality in patients due to GN BSI. The highest impact of inappropriate prescribing was seen in patients with GN BSI, which may be a useful metric to monitor the impact of AMS interventions.

Effect of prior receipt of antibiotics on the pathogen distribution and antibiotic resistance profile of key Gram-negative pathogens among patients with hospital-onset urinary tract infections

BACKGROUND

This retrospective cohort study characterized the impact of prior antibiotic exposure on distribution and nonsusceptibility profiles of Gram-negative pathogens causing hospital-onset urinary tract infections (UTI).

METHODS

Hospital patients with positive urine culture for Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and other Enterobacteriaceae ≥3 days after hospital admission were included. Assessment outcomes included the distribution of bacteria in urine cultures, antibiotic susceptibility patterns, and the effect of prior antibiotic exposure, defined as 0, 1, or ≥2 prior antibiotics, on the distribution and antibiotic susceptibility profiles of the Gram-negative organisms.

RESULTS

The most commonly isolated pathogens from 5574 unique UTI episodes (2027 with and 3547 without prior antibiotic exposure) were E. coli (49.5%), K. pneumoniae (17.1%), and P. aeruginosa (8.2%). P. aeruginosa was significantly more commonly isolated in patients with ≥2 prior antibiotic exposures (12.6%) compared with no exposure (8.2%; p = 0.036) or 1 prior exposure (7.9%; p = 0.025). Two or more prior antibiotic exposures were associated with slightly higher incidences of fluoroquinolone nonsusceptibility, multidrug resistance, and extended-spectrum β-lactamase phenotype compared with 0 or 1 exposure, suggesting an increased risk for resistant Gram-negative pathogens among hospital patients with urinary tract infections occurring ≥3 days after admission.

CONCLUSIONS

Clinicians should critically assess prior antibiotic exposure when selecting empirical therapy for patients with hospital-onset urinary tract infections caused by Gram-negative pathogens.

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.

Should the patients colonized with extended-spectrum beta-lactamase-producing Gram-negative bacilli (E-GNB) coming to hospital from the community with pneumonia get anti-E-GNB active empirical treatment?

Extended-spectrum beta-lactamases are responsible for resistance of Gram-negative bacilli to several beta-lactam antibiotics, including those prescribed for treatment pneumonia. To evaluate the importance of colonization with E-GNB for the choice of empirical treatment we performed a retrospective case-control study including 156 patients, hospitalized for treatment of pneumonia from 2009 through 2013. Empirical treatment success and in-hospital survival were significantly lower in patients colonized with E-GNB compared to non-colonized (p = 0.002, p = 0.035). When comparing subgroups of colonized patients, treatment success was significantly lower in patients who were colonized with E-GNB resistant to empirical antibiotic (p = 0.010), but not in those colonized by E-GNB susceptible to empirically given antibiotic (p = 0.104). Difference in in-hospital mortality was insignificant in both subgroups (p = 0.056, p = 0.331). The results of study suggest that an anti-E-GNB active antibiotic should be used for empirical treatment of pneumonia in E-GNB colonized patients.

Predominance of healthcare-associated cases among episodes of community-onset bacteraemia due to extended-spectrum β-lactamase-producing Enterobacteriaceae

Extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) are endemic pathogens worldwide. Infection with ESBL-PE may be associated with inadequate antibiotic therapy and a poor outcome. However, risk factors for ESBL-PE community-acquired infections are ill-defined. An observational multicentre study was performed in 50 hospitals to identify the prevalence of and risk factors for community-acquired ESBL-PE bacteraemia. All patients presenting with community-onset Enterobacteriaceae bacteraemia were recorded over a 2-month period (between June and November 2013). Risk factors and 14-day outcomes of patients were investigated. Among 682 Enterobacteriaceae bacteraemia episodes recorded, 58 (8.5%) were caused by ESBL-PE. The most frequent species isolated were Escherichia coli (537; 76.7%) and Klebsiella spp. (68; 9.7%), of which 49 (9.1%) and 8 (11.8%), respectively, were ESBL-producers. Most ESBL-PE episodes were healthcare-associated, and only 22 (38%) were apparently community-acquired. The main risk factor for community-acquired ESBL-PE bacteraemia was a prior hospital stay of ≥5 days within the past year. The overall 14-day survival was 90%; only 4 (6.9%) of 58 patients with ESBL-PE bacteraemia died. Inadequate initial antibiotic therapy was administered to 55% of patients with ESBL-PE bacteraemia but was not associated with increased 14-day mortality. Although many patients had community-onset ESBL-PE bacteraemia, almost two-thirds of the episodes were actually healthcare-associated, and true community-acquired ESBL-PE bacteraemia remains rare. In our essentially non-severely ill population, inappropriate initial therapy was not associated with a higher risk of mortality.

Intra-abdominal Infections: The Role of Anaerobes, Enterococci, Fungi, and Multidrug-Resistant Organisms

BACKGROUND

Intra-abdominal infections (IAI) constitute a common reason for hospitalization. However, there is lack of standardization in empiric management of (1) anaerobes, (2) enterococci, (3) fungi, and (4) multidrug-resistant organisms (MDRO). The recommendation is to institute empiric coverage for some of these organisms in "high-risk community-acquired" or in "healthcare-associated" infections (HCAI), but exact definitions are not provided.

METHODS

Epidemiological study of IAI was conducted at Assaf Harofeh Medical Center (May-November 2013). Logistic and Cox regressions were used to analyze predictors and outcomes of IAI, respectively. The performances of established HCAI definitions to predict MDRO-IAI upon admission were calculated by receiver operating characteristic (ROC) curve analyses.

RESULTS

After reviewing 8219 discharge notes, 253 consecutive patients were enrolled (43 [17%] children). There were 116 patients with appendicitis, 93 biliary infections, and 17 with diverticulitis. Cultures were obtained from 88 patients (35%), and 44 of them (50%) yielded a microbiologically confirmed IAI: 9% fungal, 11% enterococcal, 25% anaerobic, and 34% MDRO. Eighty percent of MDRO-IAIs were present upon admission, but the area under the ROC curve of predicting MDRO-IAI upon admission by the commonly used HCAI definitions were low (0.73 and 0.69). Independent predictors for MDRO-IAI were advanced age and active malignancy.

CONCLUSIONS

Multidrug-resistant organism-IAIs are common, and empiric broad-spectrum coverage is important among elderly patients with active malignancy, even if the infection onset was outside the hospital setting, regardless of current HCAI definitions. Outcomes analyses suggest that empiric regimens should routinely contain antianaerobes (except for biliary IAI); however, empiric antienterococcal or antifungals regimens are seldom needed.

Population Pharmacokinetic Analysis of Piperacillin/Tazobactam in Korean Patients with Acute Infections

Background

For more effective and safer usage of antibiotics, the dosing strategy should be individualized based on the patients’ characteristics, including race. The aim of this study was to investigate the population pharmacokinetic (PK) profiles of piperacillin and tazobactam in Korean patients with acute infections.

Materials and Methods

At least four consecutive 2/0.25 g or 4/0.5 g doses of piperacillin/tazobactam (TZP) were intravenously infused over 1 h every 8 h for patients with creatinine clearance (CL_cr) ≤50 ml/min or CL_cr >50 mL/min, respectively. Blood samples from 33 patients at a steady-state were taken pre-dose and at 0 min, 30 min, and 4-6 h after the fourth infusion. The population PK analysis was conducted using a non-linear mixed-effects method. A likelihood ratio test was used to select significant covariates, with significance levels of P <0.05 for selection and P <0.01 for elimination.

Results

Both piperacillin PK and tazobactam PK were well described by a two-compartment model with first-order elimination. Creatinine clearance and body weight, as covariates on clearance (CL) and volume of central compartment (V1), were selected among the covariates possibly affecting PK parameters of both drugs. CL was defined as CL = 2.9 + 4.03 × CL_cr /47 for piperacillin and CL = 1.76 + 4.81 × CL_cr /47 for tazobactam. V1 was defined as V1 = 19.5 × weight/60 for piperacillin and V1 = 22.6 × weight/60 for tazobactam.

Conclusion

The PK profiles of TZP at a steady-state in Korean patients with acute infections were well described by a two-compartment model with first-order elimination. Both piperacillin and tazobactam clearances were significantly influenced by creatinine clearance.

Sepsis Caused by Extended-Spectrum Beta-Lactamase (ESBL)-Positive K. pneumoniae and E. coli: Comparison of Severity of Sepsis, Delay of Anti-Infective Therapy and ESBL Genotype

Infections with extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) are associated with increased mortality. Outcome differences due to various species of ESBL-E or ESBL genotypes are not well investigated. We conducted a cohort study to assess risk factors for mortality in cases of ESBL-E bacteremia (K. pneumoniae or E. coli) and the risk factors for sepsis with organ failure. All consecutive patients of our institution from 2008 to 2011 with bacteremia due to ESBL-E were included. Basic epidemiological data, underlying comorbidities, origin of bacteremia, severity of sepsis and delay of appropriate anti-infective treatment were collected. Isolates were PCR-screened for the presence of ESBL genes and plasmid-mediated AmpC β-lactamases. Cox proportional hazard regression on mortality and multivariable logistic regression on risk factors for sepsis with organ failure was conducted. 219 cases were included in the analysis: 73.1% due to E. coli, 26.9% due to K. pneumoniae. There was no significant difference in hospital mortality (ESBL-E. coli, 23.8% vs. ESBL-K. pneumoniae 27.1%, p = 0.724). However, the risk of sepsis with organ failure was associated in cases of K. pneumoniae bacteremia (OR 4.5, p<0.001) and patients with liver disease (OR 3.4, p = 0.004) or renal disease (OR 6.8, p<0.001). We found significant differences in clinical presentation of ESBL-E bacteremia due to K. pneumoniae compared to E. coli. As K. pneumoniae cases showed a more serious clinical presentation as E. coli cases and were associated with different risk factors, treatment and prevention strategies should be adjusted accordingly.

Community-acquired febrile urinary tract infection caused by extended-spectrum beta-lactamase-producing bacteria in hospitalised infants

INTRODUCTION

Extended-spectrum beta-lactamase (ESBL) producing bacteria are infrequent pathogens of urinary tract infections in children. The objective of our study was to investigate the presence, clinically associated characteristics and risk factors for acquisition of urinary tract infection/acute pyelonephritis (UTI/APN) in hospitalised children <2years old caused by community-acquired ESBL.

METHODS

A case-control study in a second level community hospital in Spain, in which 537 episodes of UTI/APN were investigated in a retrospective study between November 2005 and August 2014. Cases were patients with ESBL strains. For each case, four ESBL-negative controls were selected. A questionnaire with the variables of interest was completed for every patient, and the groups were compared.

RESULTS

ESBL-positive strains were found in 19 (3,5%) cultures. Of these 16 (84%) were Escherichia coli. Vesicoureteral reflux (VUR) of any grade was more frequent in the ESBL group (60 vs. 29%), although without statistical significance. Relapses were more frequent in the ESBL group (42% vs. 18%) (P=.029; OR=3.2; 95%CI: 1.09-9.5). The prevalence of UTI/APN due to ESBL-positive strains increased slightly from 2.7% in the period 2005-2009 to 4.4% in the period 2010-2014.

CONCLUSIONS

ESBL UTI/APN were associated with more frequent relapses. VUR of any grade was twice more frequent in the ESBL group. Piperacillin/tazobactam, fosfomycin and meropenem showed an excellent activity. Aminoglycosides may be a therapeutic option, and in our patients gentamicin was the antibiotic most used.

Community-Onset Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae Invasive Infections in Children in a University Hospital in France

Limited data is available on pediatric community-onset infections with extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE), but such infections may affect both the efficacy of empiric antibiotic therapy and the rational use of antibiotics.We retrospectively analyzed data from 2007 to 2012 for all children ≤16 years old with a positive ESBL-PE strain from usually sterile sites within 48 hours of admission in a tertiary hospital in France. We analyzed healthcare- and community-associated infections among community-onset infections. In total, 3612 Enterobacteriaceae isolates were collected; the prevalence of ESBL-PE infection increased over the study period, from 2.4% to 5.1% (P < 0.001). Among the 90 children with a first community-onset ESBL-PE infection, 58% (n = 52) had a healthcare-associated infection, and 87% of isolates were susceptible to amikacin. As compared with patients with community-associated infections, those with healthcare-associated infections had fewer urinary tract infections (UTIs) (86% vs 97%) and Escherichia coli infections (35% vs 84%) and more Klebsiella pneumoniae infections (46% vs 8%). Inappropriate empiric treatment was prescribed for 54 patients (64%), but a favorable outcome was observed in 46 of 49 (94%) and 1 of 5 (20%) patients with UTIs and non-UTIs, respectively (P < 0.001). Among patients with community-associated infections, 85% had at least 1 risk factor for ESBL-PE infections. In conclusion, the prevalence of community-onset ESBL-PE infections doubled during the study period. These infections mainly occurred among children with healthcare-associated criteria or identified risk factors. Amikacin is an alternative to carbapenems for empiric treatment because most of these infections involved urinary tract and susceptible isolates.

Prevalence, risk factors and antimicrobial susceptibility pattern of extended spectrum β-lactamase-producing bacteria in a tertiary care hospital

BACKGROUND

The widespread misuse of antibiotics over the past several decades has been regarded as the contributing factor in the development of resistance toward them. Extended spectrum β-lactamases (ESBLs) are enzymes produced by certain bacteria that can make them resistant to certain antibiotics. Early detection of ESBL strains and judicious use of antibiotics and proper implementation of infection control strategies are essential to prevent the spread of this threat in the community. The study aimed at appraising the prevalence, risk factors and antimicrobial susceptibility pattern of ESBL-producing microorganisms.

METHODS

A prospective observational study was carried out in a tertiary care referral hospital located in Malappuram district of Kerala among inpatients with infection by ESBL-producing bacteria in order to estimate the prevalence, risk factors and their antibiotic susceptibility pattern.

RESULTS

Out of the total 1156 patients studied, 118 had confirmed diagnosis on the presence of ESBL-producing microorganisms. Overall, 9.79% of all samples growing Enterobacteriaceae yielded an ESBL producer. Out of the total isolates identified, 66.1% were urinary tract infections, 15.1% were respiratory tract infections, 14.4% were surgical site infections and the remaining constituted blood stream infections. The highest antimicrobial activity against ESBL-producing isolates was observed for meropenem.

CONCLUSIONS

High prevalence of ESBL-producing organisms is evident in the study setting implicating the necessity to report the ESBL production along with the routine sensitivity reports supplemented with control measures which can assist a clinician in prescribing appropriate antibiotics.

Bloodstream infections caused by multi-drug resistant Proteus mirabilis: Epidemiology, risk factors and impact of multi-drug resistance

BACKGROUND

The prevalence of antimicrobial co-resistance among ESBL-producing Enterobactereaceae is extremely high in Israel. Multidrug-resistant Proteus mirabilis strains (MDR-PM), resistant to almost all antibiotic classes have been described. The aim was to determine the risk factors for bloodstream infections caused by MDR-PM and clinical outcomes.

METHODS

A retrospective case-control study. Adult patients with PM bacteremia during 7 years were identified retrospectively and their files reviewed for demographics, underlying diseases, Charlson Comorbidity Index, treatment and outcome.

RESULTS

One hundred and eighty patients with PM-bloodstream infection (BSI) were included; 90 cases with MDR-PM and 90 controls with sensitive PM (S-PM). Compared to controls, cases more frequently were from nursing homes, had recurrent hospital admissions in the past year and received antibiotic therapy in the previous 3 months, were bedridden and suffered from peripheral vascular disease and peptic ulcer disease (p < 0.001). Two-thirds of the MDR-PM isolates were ESBL-producers vs 4.4% of S-PM isolates (p < 0.001, OR = 47.6, 95% CI = 15.9-142.6). In-hospital crude mortality rate of patients with MDR-PM BSI was 37.7% vs 23.3% in those with S-PM BSI (p = 0.0359, OR = 2, 95% CI = 1.4-3.81).

CONCLUSIONS

PM bacteremia in elderly and functionally-dependent patients is likely to be caused by nearly pan-resistant PM strains in the institution; 51.8% of the patients received inappropriate empiric antibiotic treatment. The crude mortality rate of patients with MDR-PM BSI was significantly higher than that of patients with S-PM BSI.

The challenge of antibiotic resistance in haematology patients

Bacterial infections were once a major obstacle to the treatment of acute leukaemia. Improvement in management strategies, including the use of broad-spectrum antibacterial drugs targeting Gram-negative bacteria, has reduced the mortality in neutropenic patients developing blood stream infections and other severe infections. In many countries these achievements are threatened by development of multi-resistant bacteria, such as Klebsiella pneumoniae, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus. This review addresses the epidemiology, clinical importance and possible management of these multi-resistant organisms.

The impact of revised CLSI cefazolin breakpoints on the clinical outcomes of Escherichia coli bacteremia

BACKGROUND/PURPOSE

The susceptibility breakpoints of cephalosporins for Enterobacteriaceae were revised by the Clinical and Laboratory Standards Institute (CLSI) in 2010 and 2011. The clinical outcome and susceptibility data were analyzed to evaluate the impact of revised CLSI cefazolin breakpoints on the treatment of Escherichia coli bacteremia.

METHODS

Forty-three bacteremic Escherichia coli isolates from Taichung Veterans General Hospital, Taichung, Taiwan, during the period from January 2013 to December 2013, were selected to analyze the minimum inhibitory concentration (MIC) distributions of cefazolin and the correlated clinical responses to cefazolin therapy.

RESULTS

The modal cefazolin MIC among the 43 isolates was 1 μg/mL and accounted for 18 (42%) isolates. The cumulative percentage for MICs ≤ 2 μg/mL was 79%. The conventional dosing regimens achieved clinical cure in 33 (97%) of 34 patients with bacteremia due to E. coli with a cefazolin MIC ≤ 2 μg/mL, in all of the six patients with a cefazolin MIC of 4 μg/mL, and all of the three patients with a cefazolin MIC of 8 μg/mL.

CONCLUSION

The microbiological data support the revised CLSI breakpoints of cefazolin. The conventional cefazolin dosing regimens can still achieve satisfactory clinical cure rates for bacteremia of E. coli with a cefazolin MIC ≤ 2 μg/mL in patients without severe septic shock. Before the approval of the efficacy of cefazolin for the treatment of E. coli isolates with a cefazolin MIC of 4 μg/mL, it is prudent to use cefazolin only when a high drug level can be achieved in the infection site, such as the urinary tract.

Empirical therapies among adults hospitalized for community-acquired upper urinary tract infections: A decision-tree analysis of mortality, costs, and resistance

BACKGROUND

Poor outcomes occur when patients with serious infections receive antibiotics to which the organisms are resistant.

METHODS

Decision trees simulated in-hospital mortality, costs, incremental cost-effectiveness ratio per life year saved, and carbapenem resistance according to 3 empirical antibiotic strategies among adults hospitalized for community-acquired (CA) upper urinary tract infections (UTIs): ceftriaxone (CRO) plus gentamicin (GM) in the intensive care unit (ICU), imipenem (IMP), and individualized choice (IMP or CRO) based on clinical risk factors for CA- extended-spectrum β-lactamase (ESBL).

RESULTS

The estimated prevalence of CA-ESBL on admission was 5% (range, 1.3%-17.6%); 3% and 97% were admitted to the ICU and medical ward (MW), respectively. In the ICU, CRO plus GM was dominated; IMP was cost-effective (incremental cost-effectiveness ratio: €4,400 per life year saved compared with individualized choice). In the MW, IMP had no impact on mortality and was less costly (-€142 per patient vs CRO, -€38 vs individualized choice). The dominance of IMP was consistent in sensitivity analyses. Compared with CRO, colonization by carbapenem-resistant pathogens increased by an odds ratio of 4.5 in the IMP strategy.

CONCLUSION

Among the ICU patients, empirical IMP therapy reduces mortality at an acceptable cost. Among MW patients, individualized choice or CRO is preferred to limit carbapenem resistance at a reasonable cost.

Prevalence, risk factors, and impact on clinical outcome of extended-spectrum beta-lactamase-producing Escherichia coli bacteraemia: a five-year study

BACKGROUND

The impact of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) bacteraemia on outcome remains controversial.

METHODS

A retrospective analysis of the prevalence, risk factors, clinical features, and outcomes of all ESBL-EC bacteraemia in one French hospital over a 5-year period was performed. A case-control study was undertaken: cases had at least one ESBL-EC bacteraemia and controls a positive non-ESBL-EC bacteraemia.

RESULTS

The prevalence of ESBL-EC bacteraemia increased from 5.2% of all positive E. coli blood cultures in 2005 to 13.5% in 2009 (p<0.003). CTX-M represented 70% of ESBL-EC bacteraemia strains, and strains were not clonally related. On adjusted analysis, the only significant risk factor for ESBL-EC bacteraemia was a previous ESBL-EC colonization (odds ratio 11.3, 95% confidence interval 1.2-107; p=0.003). Initial antimicrobial therapy was less frequently adequate in the ESBL-EC group (48% vs. 85%; p=0.003). The presence of ESBL-EC bacteraemia was not associated with a longer hospital stay (p=0.088). Day 30 mortality was high, but not significantly different in the two groups (30% vs. 27%; p=0. 82).

CONCLUSION

The prevalence of ESBL-EC bacteraemia has been increasing dramatically. Previous colonization with ESBL-EC was a strong risk factor for ESBL-EC bacteraemia. More inadequate initial antimicrobial therapy was noted in the ESBL-EC group, but mortality and length of hospital stay were not significantly different from those of patients with non-ESBL-EC bacteraemia.

β-lactam and β-lactamase inhibitor combinations in the treatment of extended-spectrum β-lactamase producing Enterobacteriaceae: time for a reappraisal in the era of few antibiotic options?

The spread of extended-spectrum β-lactamase (ESBL) genes in Enterobacteriaceae such as Escherichia coli or Klebsiella spp is a major challenge to modern medical practice. Carbapenems are the treatment of choice for serious infections caused by ESBL producers; however, carbapenem resistance has increased globally. ESBL producers might be susceptible to β-lactam-β-lactamase inhibitor (BLBLI) combination antibiotics such piperacillin-tazobactam or amoxicillin-clavulanate. These drugs are frequently avoided in serious infections caused by ESBL producers because of the inoculum effect in-vitro (especially for piperacillin-tazobactam), animal data suggesting inferior efficacy when compared with carbapenems, concerns about pharmacokinetic-pharmacodynamic drug target attainment with standard doses, and poor outcomes shown in some observational studies. Prospective cohort data and a meta-analysis suggest that BLBLIs are non-inferior to carbapenems in the treatment of bloodstream infections caused by ESBL producers. We examine why BLBLIs are perceived as inferior in the treatment of infection with ESBL producers, and discuss data that suggest these concerns might not be strongly supported by clinical evidence.

Meropenem versus piperacillin-tazobactam for definitive treatment of bloodstream infections due to ceftriaxone non-susceptible Escherichia coli and Klebsiella spp (the MERINO trial): study protocol for a randomised controlled trial

Background

Gram-negative bacteria such as Escherichia coli or Klebsiella spp. frequently cause bloodstream infections. There has been a worldwide increase in resistance in these species to antibiotics such as third generation cephalosporins, largely driven by the acquisition of extended-spectrum beta-lactamase or plasmid-mediated AmpC enzymes. Carbapenems have been considered the most effective therapy for serious infections caused by such resistant bacteria; however, increased use creates selection pressure for carbapenem resistance, an emerging threat arising predominantly from the dissemination of genes encoding carbapenemases. Recent retrospective data suggest that beta-lactam/beta-lactamase inhibitor combinations, such as piperacillin-tazobactam, may be non-inferior to carbapenems for the treatment of bloodstream infection caused by extended-spectrum beta-lactamase-producers, if susceptible in vitro. This study aims to test this hypothesis in an effort to define carbapenem-sparing alternatives for these infections.

Methods/Design

The study will use a multicentre randomised controlled open-label non-inferiority trial design comparing two treatments, meropenem (standard arm) and piperacillin-tazobactam (carbapenem-sparing arm) in adult patients with bacteraemia caused by E. coli or Klebsiella spp. demonstrating non-susceptibility to third generation cephalosporins. Recruitment is planned to occur in sites across three countries (Australia, New Zealand and Singapore). A total sample size of 454 patients will be required to achieve 80% power to determine non-inferiority with a margin of 5%. Once randomised, definitive treatment will be for a minimum of 4 days, but up to 14 days with total duration determined by treating clinicians. Data describing demographic information, antibiotic use, co-morbid conditions, illness severity, source of infection and other risk factors will be collected. Vital signs, white cell count, use of vasopressors and days to bacteraemia clearance will be recorded up to day 7. The primary outcome measure will be mortality at 30 days, with secondary outcomes including days to clinical and microbiological resolution, microbiological failure or relapse, isolation of a multi-resistant organism or Clostridium difficile infection.

Trial registration

The MERINO trial is registered under the Australian New Zealand Clinical Trials Register (ANZCTR), reference number: ACTRN12613000532707 (registered 13 May 2013) and the US National Institute of Health ClinicalTrials.gov register, reference number: NCT02176122 (registered 24 June 2014).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-014-0541-9) contains supplementary material, which is available to authorized users.