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.

Evaluation of PCR-based testing for surveillance of KPC-producing carbapenem-resistant members of the Enterobacteriaceae family.

The spread of carbapenem-resistant members of the Enterobacteriaceae family (CRE) harboring carbapenemases is an emerging public health threat. As KPC-producing Klebsiella species are endemic in our tertiary care hospital, we aimed to evaluate a PCR-based surveillance test for identification of rectal carriage of KPC-producing CRE. We conducted a surveillance study between May and December 2007. Rectal swabs were collected from patients known to harbor CRE and from contacts of newly discovered patients harboring CRE. Specimens were evaluated by culture and by PCR analysis for blaKPC and were defined as positive if CRE was cultured and blaKPC was identified. Discrepant results between the culture and PCR analysis were resolved by subculturing, repeating the PCR, and performing a hydrolysis assay. Positive CRE cultures prior or subsequent to the time of sampling for the study were also taken into consideration. Sensitivity, specificity, and time to result were calculated. A total of 755 swabs were included. Concordant results were documented for 735 specimens; 51 were positive as determined by both PCR and culture. Discrepancies existed for 20 swabs; 9 were blaKPC negative and CRE culture positive, and 11 were blaKPC positive and CRE culture negative. After repeat testing, a total of 64 samples were classified as blaKPC-positive CRE. The sensitivity and specificity of the PCR analysis were 92.2% and 99.6%, respectively, and those of the culture were 87.5% and 99.4%, respectively. Over the last 3 months of the study, the sensitivity of the PCR improved to 96.3%, versus 77.8% for culture. Time to result was 30 h for the PCR and 60 h (negative) and 75 h (positive) for the CRE culture. blaKPC PCR-based testing is a useful method for the surveillance of KPC-producing CRE. Its main advantage over culturing is a shorter time to result, and it may prove to be more sensitive.

Determinants of inappropriate empirical antibiotic treatment: systematic review and meta-analysis.

This systematic review assessed study-level determinants of non-covering (inappropriate) empirical antibiotic treatment (IEAT), focusing on the influence of study years and the prevalence of multidrug-resistant organisms (MDROs) in the study. Prospective and retrospective observational studies reporting on the association between IEAT and mortality in adult patients with microbiologically documented infections published between 2008-2016 were included. A meta-analysis of IEAT rates was conducted using a random-effects model. Subgroup analyses and mixed-effect single-covariate meta-regression were conducted to identify the association between clinical and methodological study-level covariates and IEAT rates. Heterogeneity was assessed using the I2 measure of inconsistency. Multi-covariate meta-regression was conducted including variables with a P-value of <0.1 on single-covariate analysis. A total of 191 studies were included assessing 73 595 patients, most commonly with bacteraemia. The pooled IEAT event rate was 32% [95% confidence interval (CI) 30-35%], with large heterogeneity (I2 = 97.7%). On multi-covariate analyses, the prevalence of any MDRO [odds ratio (OR) per 10% increase in prevalence = 1.11, 95% CI 1.07-1.15], Acinetobacter spp. specifically (OR = 1.99, 95% CI 1.22-3.25) and advancing study years were associated with IEAT rates (OR = 1.03, 95% CI 1.00-1.06 per year). MDRO rates were independently associated with mortality rates in the studies, adjusting to the rate of IEAT. The prevalence of MDROs, mainly multidrug-resistant Gram-negative bacteria, is significantly associated with the probability of prescribing IEAT and mortality rates in recent studies. We show how antibiotic resistance impacts patient management and outcomes.

Prevalence and risk factors for carriage of extended-spectrum ß-lactamase-producing Enterobacteriaceae among patients prior to bowel surgery.

Prophylactic antibiotics are an important measure in preventing perioperative infection, Failure to cover multidrug-resistant pathogens may place carriers at increased risk of infection. We conducted a prospective, cross-sectional study in patients prior to bowel surgery to measure the carriage prevalence of extended-spectrum ß-lactamase-producing Enterobacteriaceae and identify risk factors for carriage in this population. During an 11-month period, 150 patients were eligible for inclusion. 27 patients (18%) were found to be carriers of extended-spectrum ß-lactamase-producing Enterobacteriaceae. Factors independently associated with carriage were immunosuppressive therapy (OR, 4.09; 95% CI 1.55-10.81; P = 0.005) and receipt of antibiotics in the prior 3 months (OR, 2.59; 95% CI 1.08-6.24; P = 0.033). Detection of a population at risk for carriage may help in devising and modifying appropriate antibiotic regimens for surgical prophylaxis in carriers of multidrug-resistant bacteria.