Association between antibiotic pressure and the risk of colonization/infection by multidrug-resistant Acinetobacter baumannii complex: a time series analysis

Abstract

Introduction. To analyze the association between antibiotic pressure and the risk of colonization/infection by Acinetobacter baumannii complex (AB), evaluating both the individual and general prescriptions of antibiotics. Methods. This is an analytical, observational, case-control study on patients admitted to an Intensive Care Unit (ICU) during an AB outbreak (14 months). A five-year time series was constructed with the monthly incidence of cases of infection/colonization with strains of AB resistant to each antibiotic administered and with the monthly consumption of these antibiotics in the ICU. Results. We identified 40 patients either infected (23) or colonized (17) by AB and 73 controls. We found an epidemic multidrug-resistant clone of AB in 75% of cases. Risk factors associated with the development of AB infection/colonization were: greater use of medical instruments, the presence of a tracheostomy, cutaneous ulcers, surgical lesions and prior antibiotic therapies. The regression analysis of individual use of antibiotics showed that prior treatment with ceftazidime, ceftriaxone, amoxicillin/clavulanate, imipenem, levofloxacin, linezolid, and vancomycin was a risk factor for acquiring AB. ARIMA models showed that the relationship were greatest and statistically significant when the treatment occurred between 6 months (ceftazidime) and 9 months (imipenem and levofloxacin) prior. Conclusions. The dynamic and aggregate relationship between the incidence of infection/colonization by multidrug-resistant strains of AB and prior antibiotic treatment was statistically significant for intervals of 6 to 9 months.

Insights into the epidemiology, risk factors, and clinical outcomes of carbapenem-resistant Acinetobacter baumannii infections in critically ill children

“…Long-term and high frequency use of such antibiotics makes A. baumannii undergo gene mutation or acquire new resistance genes to survive under the pressure of antibiotics, resulting in changes in the resistance characteristics of bacteria ( 28 ). This phenomenon was mainly observed when the treatment had occurred between 6 months (ceftazidime) and 9 months (imipenem and levofloxacin) prior ( 29 ). Considering these factors, hospitals should strengthen antibiotic management and pay more attention to patients with CSAB infection who have prior exposure to carbapenems.…”