Abrupt Increase in Rate of Imipenem Resistance in Acinetobacter baumannii Complex Strains Isolated from General Hospitals in Korea and Correlation With Carbapenem Administration During 2002-2013

Trends and Correlation Between Antimicrobial Resistance and Antibiotics Consumption in a Specialist Children’s Hospital from 2016 to 2021

Purpose

To explore the trends and correlation between antibiotics consumption and antimicrobial resistance in children in a specialist hospital from 2016–2021 in China.

Patients and Methods

This retrospective study investigated data on the consumption of antibiotics and antimicrobial resistance in children. Antibiotics consumption was expressed as defined daily doses (DDDs)/1000 patient-days based on the Guidelines for Anatomical Therapeutic Chemical. The trends in antibiotics consumption and antimicrobial resistance rates were analyzed by linear regression, while Spearman correlation analysis was employed to evaluate their correlations.

Results

An increasing trend in the annual consumption of carbapenems and monobactams was detected (all P<0.05). A significant upward trend was detected in the annual resistance rates of Enterococcus faecium to ciprofloxacin, Streptococcus pneumonia to ceftriaxone, Acinetobacter baumannii to carbapenems, Enterobacter cloacae to carbapenems, Pseudomonas aeruginosa to ceftazidime, and Escherichia coli to cefepime, while the annual resistance rates of Escherichia coli to carbapenems had a significant downward trend (all P<0.05). The consumption of cephalosporin/β-lactamase inhibitor (C/BLI) combinations and carbapenems had significant positive correlations with the resistance rates of Acinetobacter baumannii to carbapenems (r=0.763, P<0.001; r=0.806, P<0.001), Enterobacter cloacae to carbapenems (r=0.675, P<0.001; r=0.417, P=0.043), and Pseudomonas aeruginosa to ceftazidime (r=0.625, P=0.001; r=0.753, P<0.001), respectively. Also, increasing consumption of monobactams was related to the upward resistance rates of Acinetobacter baumannii to carbapenems (r=0.557, P=0.005) and Enterobacter cloacae to carbapenems (r=0.507, P= 0.011).

Conclusion

This study demonstrated significant positive associations between antibiotics consumption and specific antimicrobial resistance rates. The current findings pointed out some directions to pursue in controlling the prevalence of certain resistant bacterial strains in children.

Trends and correlation between antibacterial consumption and carbapenem resistance in gram-negative bacteria in a tertiary hospital in China from 2012 to 2019

Background

To investigate the trends and correlation between antibacterial consumption and carbapenem resistance in Gram-negative bacteria from 2012 to 2019 in a tertiary-care teaching hospital in southern China.

Methods

This retrospective study included data from hospital-wide inpatients collected between January 2012 and December 2019. Data on antibacterial consumption were expressed as defined daily doses (DDDs)/1000 patient-days. Antibacterials were classified according to the Anatomical Therapeutic Chemical (ATC) classification system. The trends in antimicrobial usage and resistance were analyzed by linear regression, while Pearson correlation analysis was used for assessing correlations.

Results

An increasing trend in the annual consumption of tetracyclines, β-lactam/β-lactamase inhibitor (BL/BLI) combinations, and carbapenems was observed (P < 0.05). Carbapenem resistance in Acinetobacter baumannii (A. baumannii) significantly increased (P < 0.05) from 18% in 2012 to 60% in 2019. Moreover, significant positive correlations were found between resistance to carbapenems in A. baumannii (P < 0.05) and Escherichia coli (E. coli; P < 0.05) and consumption of carbapenems, while the resistance rate of A. baumannii to carbapenems was positively correlated with cephalosporin/β-lactamase inhibitor (C/BLI) combinations (P < 0.01) and tetracyclines usage (P < 0.05). We also found that use of quinolones was positively correlated with the resistance rate of Burkholderia cepacia (B. cepacia) to carbapenems (P < 0.05), and increasing uses of carbapenems (P < 0.01) and penicillin/β-Lactamase inhibitor (P/BLI) combinations (P < 0.01) were significantly correlated with reduced resistance of Enterobacter cloacae (E. cloacae) to carbapenems.

Conclusion

These results revealed significant correlations between consumption of antibiotics and carbapenem resistance rates in Gram-negative bacteria. Implementing proper management strategies and reducing the unreasonable use of antibacterial drugs may be an effective measure to reduce the spread of carbapenem-resistant Gram-negative bacteria (CRGN), which should be confirmed by further studies.

Colistin Plus Carbapenem versus Colistin Monotherapy in the Treatment of Carbapenem-Resistant Acinetobacter baumannii Pneumonia

Purpose

Colistin alone may not be sufficient for treating carbapenem-resistant Acinetobacter baumannii (CRAB); thus, efforts are needed to increase treatment success rates. We compared the effects of colistin plus carbapenem therapy versus colistin monotherapy in treating pneumonia caused by CRAB and attempted to identify specific populations or factors that could benefit from combination therapy.

Methods

We retrospectively collected data on cases of CRAB pneumonia. The patients were divided into colistin plus carbapenem therapy and colistin monotherapy groups. The primary outcome was 14-day mortality. The secondary outcomes were in-hospital mortality, clinical improvement at days 2 and 14, and microbiological improvement at day 14.

Results

Of 160 cases meeting criteria for CRAB pneumonia, 83 (52%) and 77 (48.0%) were treated with carbapenem combination therapy or colistin monotherapy, respectively. Among these patients, 50 (63.3%) in the combination group and 27 (39.7%) in the monotherapy group had Acute Physiologic Assessment and Chronic Health Evaluation (APACHE) II scores >24 points (p=0.010). Overall, there was no significant difference in 14-day mortality between the combination and monotherapy groups (24.1% vs 20.8%, p=0.616). Clinical improvement and sputum-negative conversion also showed no significant difference. After adjusting for disease severity according to APACHE II score, the 14-day mortality was significantly lower in the combination group than in the monotherapy group among patients with APACHE II scores of 25–29 points (9.1% vs 53.8%, P=0.020).

Conclusion

Despite more severe conditions, compared with colistin monotherapy, colistin plus carbapenem combination therapy showed equivalent primary mortality outcome in treating CRAB pneumonia. Combination therapy was more effective in patients with APACHE II score ranging from 25 to 29 points.

Prevalence and Mechanisms of Carbapenem Resistance Among Acinetobacter baumannii Clinical Isolates in Egypt

The increasing number of carbapenem-resistant Acinetobacter baumannii clinical isolates is a major concern, which restricts therapeutic options for treatment of serious infections caused by this emerging pathogen. The aim of this work is to assess the antimicrobial resistance profile and identify the molecular mechanisms involved in carbapenem resistance in A. baumannii isolated from different clinical sources in Mansoura University Hospitals, Egypt. Antimicrobial susceptibility testing has shown that resistance to carbapenem has dramatically increased (98%) with concomitant elevated levels of resistance to quinolones, trimethoprim/sulfamethoxazole, and aminoglycosides. Polymyxin B and colistin are considered the last resort. Random amplified polymorphic DNA (RAPD) typing method revealed great diversity among A. baumannii isolates. Coexistence of diverse intrinsic and acquired carbapenem-hydrolyzing β-lactamases has been detected in the tested isolates: Ambler class A: bla_KPC (56%) and bla_GES (48%), and Ambler class B: bla_NDM (30%), bla_SIM (28%), bla_VIM (20%), and bla_IMP (10%). Most isolates (94%) carried bla_OXA-23-like and bla_OXA-51-like simultaneously. bla_OXA-23-like was preceded by ISAba1 providing a potent promoter activity for its expression. Sequencing analysis revealed that ISAba1 has been also inserted in carbapenem resistance-associated outer membrane protein (OMP) (carO) gene in three isolates, two of which were clonal based on RAPD typing, leading to interruption of its expression as confirmed by SDS-PAGE analysis of OMP fractions. Carbapenem resistance genes are widely distributed among A. baumannii clinical isolates from different clinical sources. Therefore, enhanced infection control measures, effective barriers, and rational use of antimicrobials should be enforced in hospitals for minimizing the widespread resistance to carbapenems and all other antibiotics.

Epidemiology and treatment of antimicrobialresistant gram-negative bacteria in Korea

Antimicrobial resistance is becoming one of the greatest challenges to public health worldwide. Infections by antimicrobial-resistant organisms could result in the failure of treatment, increased medical costs, prolonged hospital stays, and an increased socioeconomic burden. Antimicrobial usage in Korea remains heavy, even after much effort to reduce their use. According to the Korean antimicrobial resistance surveillance system, the resistance rates of many bacteria are increasing. The resistance rate of Acinetobacter baumannii to imipenem in Korea increased to 85% in 2015, representing a major public threat. The reports of increased carbapenem resistance in Enterobacteriaceae are worrisome. More importantly, some carbapenem-resistant Enterobacteriaceae may result from the production of carbapenemases, which break down carbapenems. There are relatively few treatment options for extensively drug-resistant A. baumannii and carbapenem-resistant Enterobacteriaceae. Most reports are retrospective observational studies. Because there are little published data from randomized controlled trials, more data assessing antimicrobial treatment for extensively drug-resistant A. baumannii and carbapenem-resistant Enterobacteriaceae are needed to make treatment recommendations.