Investigation of .BETA.-lactamase genes and outer membrane porin gene in multidrug-resistant Acinetobacter baumannii

OBJECTIVE To investigate the distribution and variation of β-lactamase genes,and outer membrane porin gene in multidrug-resistant Acinetobacter baumannii. METHODS From Nov 2008 to Dec 2009,30 strains of A.baumannii isolated from inpatients were collected from Hangzhou Yuhang Hospital of Traditional Chinese Medicine.Then,three-dimensional modified test was performed to detect activities of cephalosporinase(AmpC),extended spectrum beta-lactamases(ESBLs) and metallo-beta-lactamases(MBL).Furthermore,24 kinds of β-lactamase genes and outer membrane porin gene carO were analyzed by PCR. RESULTS In 30 strains of A.baumannii,3 kinds of acquired β-lactam-resistance genes TEM,ADC,OXA-23 were detected,with the positive rates of 100.0%,60.0%,80.0% respectively.and ADC gene in Strain NO.30 was a new subtype.All outer membrane porin gene carO had mutations(100.0%). CONCLUSION In this group of A.baumannii,3 kinds of β-lactamase genes,TEM,ADC,OXA-23,and outer membrane porin carO gene might play a role in its resistance to β-lactam antimicrobial agents.