An investigation of drug-resistant Acinetobacter baumannii infections in a comprehensive hospital of East China

BACKGROUND: To investigate the drug resistant gene profiles and molecular typing of Acinetobacter baumannii isolates collected from clinical specimens in a comprehensive hospital, Jiangsu province. METHODS: This study included 120 patients in a comprehensive hospital with drug-resistant A. baumannii infections on clinical specimens from October 2011 to December 2013. Antibiotic susceptibility test was determined by Vitek 2 Compact system. OXA-51, OXA-23, OXA-24, OXA-58, VIM, IMP, SHV, GES, TEM, AmpC, qacEΔ1-sul1, intI l, CarO, aac(6′)-Ib, and aac(6′)-II were analyzed by PCR. The analysis of molecular typing for 50 multidrug resistant A. baumannii isolates was performed by PFGE. RESULTS: A total of 64(53%) isolates were multidrug-resistant A.baumannii. The antibiotic susceptibility tests showed that the resistant rates to common antibiotics of mutidrug-resistant A. baumannii were extremely high, most of which over 60%. One hundred and ten isolates harbored OXA-51 (91.7%), 100 for OXA-23(83.3%), 103 for VIM-1(85.8%), 90 for AmpC(75.00%), 50 for aac(6′)-Ib(41.7%), 77 for the loss of CarO (64.2%), 85 for intl1(70.8%), and 64 for qacEΔ1-sul1(53.33%), while OXA-24 was undetected. Fifty multidrug-resistant A. baumannii isolates belong to 14 clones according to the PFGE DNA patterns. Main clone A includes 24 isolates, while clone B and clone C includes 6 and 9 isolates, respectively and others with no common source identified. CONCLUSION: There is high morbidity of A. baumannii infections in the hospital, especially in ICU and sputum is the most common sample type.The mainly drug-resistant genes of A. baumannii are OXA-51, OXA-23, and VIM-1 in the hospital. Clonal dissemination provides evidence for the prevalence of multidrug-resistant A. baumannii among clinical isolates. It is suggested that there is an urgent need for effective control and prevention measures.