多重耐药不动杆菌16S rRNA甲基化酶和同源性研究

Objective To characterize 16S rRNA methylase encoding genes associated with aminoglycoaides resistance, gene cassettes of class Ⅰ integrons of the multidrug-resistant Acinetobctcter spp. The sixty one Acinetobacter isolates were collected at the Second Hospital of Shanxi Medical Uni versity from July, 2007 to May, 2008. Methods Species identification was confirmed by sequence analysis of the blaOXA-51-like gene and 16S-23S rRNA gene space-region. Antimierobial susceptibility tests were performed by agar dilution method. 16S rRNA methylaae encoding genes and gene cassettes associated with integrons were amplified by PCR method. Results Among the sixty one strains, there were fifty five of Acinetobacter baumannii, three genospecies 3TU, one 13TU, one Aeinetobaeter ealcoacetieus, and one Aeinetobaeter haemolytieus. Forty eight isolates showed high-level resistance to three aminoglyeosides, including amikaein, tobramyein and gentamicin. The armA gene was found in 47 isolates and all isolates were negative for rmtA, rmtB, rmtC and rmtD genes. The Intl gene was found in 27 isolates. The gene cassettes contained arr-3, accA4,ctacCI ,catB8, aadA1 or dfrA12 genes. According to the PFGE DNA patterns, 5 distinct clones of armA-pasitive strains were identified. Clone A and Clone B were the dominant clones, widely distributed among different divisions. Condnsions 16S rRNA methylase encoding gene (armA) distributed widely in muhidrug-resistant Acinetobacter spp. The armA gene is not located in class Ⅰintegron. The class Ⅰ integron carries multiple resistant genes associated with aminoglycosides and chloramphenieol resistance.PFGE analysis suggests that armA-pesitive strains are widely spread in our hospitaL Effective infection control measure should be conducted in order to control the outbreak of resistant bacteria.

16S rRNA methylase and genetic relateness of multidrug-resistant Acinetobacter spp.