Case-case-control study of risk factors of carbapenem-resistant Acinetobacter baumannii infection

Objective To assess the risk factors of carbapenem-resistant Acinetobacter baumannii (CRAB) infection. Methods Clinical data of patients with positive bacterial culture in Tianjin Medical University General Hospital during January 2011 and December 2015 were retrospectively analyzed, including 68 patients with carbapenem resistant Acinetobacter baumannii (CRAB) bacteremia, 68 patients with carbapenem sensitive Acinetobacter baumannii (CSAB) bacteremia, and 68 patients with positive culture of other bacteria (control group). The risk factors of Acinetobacter baumannii infection were analyzed by univatiate and multivariate Logistic regression analyses. Results Univariate analysis showed that bacteremia/sepsis, use of carbapenems, β-lactamase inhibitor compound, tigecycline, combined antibiotics, glucocorticoids, surgery within one month, mechanical ventilation, central venous catheters(CVCs), arteriopuncture, indwelling catheter≥3 days and indwelling gastric tube were risk factors of CRAB infection (CRAB vs. control: χ2=4.96, 15.56, 7.64, 9.22, 5.89, 6.80, 17.00, 11.83, 18.22, 8.24, 25.24 and 7.70, P<0.05 or P<0.01, respectively); while use of third-generation cephalosporin, CVCs, length of hospital stay were risk factors of CSAB infection (CSAB vs. control: χ2=11.93 and 6.94, U=1555, P<0.05). Multivariate logistic analysis showed that bacteremia/sepsis (OR=4.01, 95%CI: 1.13~14.20), use of carbapenems (OR=4.17, 95%CI : 1.79~9.73), CVCs (OR=2.93, 95% CI: 1.22~7.08), indwelling catheter≥3 days (OR=6.08, 95%CI: 2.39~15.46) were independent risk factors of CRAB infection; use of third-generation cephalosporin (OR=3.98, 95% CI : 1.88~8.43 ), CVCs(OR=3.40, 95% CI: 1.48~7.81) were independent risk factors of CSAB infection. Conclusions Long-term use of carbapenems and invasive procedures are associated with CRAB infection, strict control of invasive procedures and rational use of antibiotics may reduce CRAB infection. Key words: Acinetobacter baumannii; Drug resistance, multiple; Risk factors; Case-case-control study