Beta-Lactamase Gene Expression Level of Hospital-Acquired CRAB Isolated from Children in Picu

Abstract

Purpose

Acinetobacter baumannii is a major cause of hospital-acquired infections. Studies showed that carbapenem resistance was related to mortality. Carbapenem resistance depends on expression of β-lactamase in adults. The present study explores the relationship between β-lactamase gene expression and carbapenem resistance and outcomes in children with A. baumannii infections.

Patients and Methods

We gathered clinical data of 131 children diagnosed with hospital-associated A. baumannii infections from the pediatrics unit of Shengjing Hospital of China Medical University. We obtained 131 isolates of A. baumannii, determined the minimal inhibitory concentrations (MICs) for common antibiotics, and measured carbapenemase-encoding genes expression using real-time PCR.

Results

We isolated 131 strains, 89 of which were carbapenem-resistant (MIC ≥ 8 µg/mL), and 42 carbapenem-sensitive strains. Univariate analysis identified statistically significant differences between the carbapenem-resistant group and the carbapenem-sensitive group for in-hospital days before infection, previous deep vein catheterization, previous urinary catheterization, previous treatment with a carbapenem (meropenem/imipenem), and expression of oxa-51 and oxa-23. Logistic regression analysis of factors associated with carbapenem-resistant A. baumannii infections found significant associations with oxa-23 expression (hazard ratio [HR] 0.005, confidence interval [CI] 95% 0–0.153, P = 0.002) and previous carbapenem treatment (HR 0.031 CI 95% 0.1–0.959, P = 0.042). Of 131 patients, 27 died within 30 days. Cox regression analysis of factors associated with 30-day mortality from A.baumannii infections showed that cephalosporin combined with sulbactam (HR 0.271, CI 95% 0.101–0.723, P = 0.009) was associated with 30-day survival.

Conclusion

The expression of oxa-23 and the use of carbapenems were independent risk factors for carbapenem resistance. The use of cephalosporins combined with sulbactam was independently associated with 30-day survival. We recommend using cephalosporins combined with sulbactam in children infected with A. baumannii.

Keywords:

• β-lactamase geen
• carbapenem resistance
• Acinetobacter baumannii
• prognosis
• risk factors

Acknowledgments

Thanks for the support of laboratory department.

Abbreviations

MODS, multiple organ dysfunction syndrome; Real-time PCR, real-time reverse-transcription polymerase chain reaction; A. baumannii, Acinetobacter baumannii; ALT, alanine aminotransferase; AST, aspartate transaminase; CRP, C-reaction protein; PLT, platelet; WBC, white blood cell; Procalcitonin; IgG, immunoglobulin G; IgA, immunoglobulin A; IgM, immunoglobulin M; T cell, T-lymphocyte; B cell, B-lymphocyte; NK cell, natural killer cell; CRRT, continuous renal replacement therapy; PICU, pediatric intensive care unit; CSF, cerebrospinal fluid; AMK, amikacin; GEN, gentamicin; SCF, sulbactam and cefoperazone; FEP, cefepime; CAZ, ceftazidime; AMP, ampicillin; SAM, ampicillin/sulbactam; TZP, piperacillin sodium/tazobactam sodium; SXT, compound sulfamethoxazole; CIP, ciprofloxacin; LVX, levofloxacin; TCY, tetracycline; TGC, tigecycline.

Ethical Consideration

The ethical approval was obtained from the Ethical Review Committee of Shengjing Hospital Affiliated to China Medical University. Since we reviewed the secondary data and obtained the clinical director’s informed consent, the patient’s informed consent was not required. Strict confidentiality during the data collection process, data processing and report writing process. The research was also conducted in accordance with the Declaration of Helsinki.

Author Contributions

All authors contributed to data analysis, drafting or revising the article, gave final approval of the version to be published, agreed to the submitted journal, and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.