Resistance and infection analysis of multidrug-resistant Acinetobacter baumannii in intensive care unit

Abstract

Objective In order to prevent the infection of Acinetobacter baumannii and use antibiotics rationally, the clinical infection and drug resistant data of multi-drug resistance Acinetobacter baumannii (MRAB) detected in intensive care unit (ICU) of Beijing Friendship Hospital from 2011 to 2013were analyzed. Methods This study is a retrospective study. One hundred and eighty five strains of MRAB were collected from the patients in ICU from January 2011 to December 2013. Identificationand antibiotic susceptibility of strains were determined with Vitek-2 Compact automatic bacteria identification system. The annual infection rate of MRAB was counted. PCR was used to detect the resistance genes. The clinical features of the patients with MRAB were analyzed. The average age, acute physiology and chronic health evaluation (APACHE) Ⅱ score, duration in ICU and mortality ratio of the MRAB patients were compared with the patients without MRAB. Rank-sum test was used to analyze the average age, APACHE Ⅱscore and duration in ICU. Chi-squared test was used to analyze the mortality ratio and annual infection rate. Results The average age [(67±17) vs (59±19) years old, Z=-5.365, P=0], APACHEⅡ score [(25.68±7.93) vs (17.62±8.39), Z=-14.821, P=0], duration in ICU [(27±29) vs (5±8) d, Z=-4.342, P=0] and mortality ratio [10.82% (53/185) vs 28.65% (147/1 359), χ2=45.92, P=0] of the patients infected by MRAB were significantly higher than those without the infection. The MRAB was found mostly in sputum and bronchial precipitates (83.78%, 155/185). Though detection rate reduced yearly and there was a significant reduction in 2013 compared with 2011 [11.07% (69/469) vs 8.37% (52/621), χ2=8.755, P=0.003], the drug resistant rate was in high level and did not show any change in the 3 years. OXA-23 and OXA-51 were detected in all MRAB. Conclusions The main drug resistant mechanism of MRAB in ICU is related to OXA-23. More active methods of control and prevention of MRAB should be used in elderly and severely pneumonic patients. Intensive disinfection and isolation measures can decrease MRAB detection rate. Combined antibiotics should be used in patients with MRAB infection. (Chin J Lab Med, 2015, 38: 55-58) Key words: Acinetobacter baumannii; Drug resistance, multiple, bacterial; Intensive care units