Molecular epidemiology of Acinetobacter baumannii strains from elderly patients with chronic obstructive pulmonary disease

OBJECTIVE To investigate the molecular epidemiology of Acinetobacter baumannii isolates from the elderly patients with chronic obstructive pulmonary disease(COPD) in the hosptial.METHODS Fifty-seven A.baumannii isolates were collected during the period between 2009 and 2011.All isolates were subjected to the Whonet 5.6 software to analyze the susceptibility,and the most prevalent clone genealogy of A.baumannii was identified with the multiple PCR based on the genotype sequencing,the enzyme digestion and PFGE trial of genome DNA of the study strains were performed;PCR and gene sequencing were used to detect the 10 drug resistance-related genes,the corresponding drug resistance gene spectra were analyzed and named.RESULTS The drug resistance rate to the 15 antibiotics tested varied between 70.2% and 98.2% except the drug resistance rate to polymycin B was 8.8%;the majority of isolates(59.6%) belonged to the defined RGP1;all isolates were broadly classified into 18 genotypes by PFGE typing with a similarity coefficient of 87.0%,and PFGE type A was a predominant clone,accounting for 59.65%;there were totally 15 types of resistance gene spectra detected,among which RGP1 accounted for 52.63%.CONCLUSION The prevalent clonal lineages of A.baumannii isolated from the elderly COPD patients may be highly homologous to European clone Ⅱ;the carrying rate of the multidrug-resistance realted genes which can horizontally transfer through the A.baumannii strains with various genetic backgrounds is high.