CHARACTERIZATION OF THE AAC(6')-IB GENE ENCODING AN AMINOGLYCOSIDE 6'-N-ACETYLTRANSFERASE IN PSEUDOMONAS-AERUGINOSA BM2656
CHARACTERIZATION OF THE AAC(6')-IB GENE ENCODING AN AMINOGLYCOSIDE 6'-N-ACETYLTRANSFERASE IN PSEUDOMONAS-AERUGINOSA BM2656
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DOI：
10.1128/aac.37.7.1456
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发表时间：
1993-07-01
影响因子：
4.9
通讯作者：
COURVALIN, P
中科院分区：
文献类型：
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作者：
GALIMAND, M;LAMBERT, T;COURVALIN, P
纸片扩散法检测铜绿假单胞菌BM 2656对妥布霉素耐药，对庆大霉素和阿米卡星敏感。这种不寻常的耐药性不能通过与大肠杆菌或铜绿假单胞菌PAO 38接合而转移，并且在该菌株中未检测到质粒DNA。将含有妥布霉素抗性基因的0.9kb片段从BM 2656克隆到pUC 18中，产生pAT 129。BM 2656和E.结果表明，妥布霉素耐药是由于合成了氨基糖苷类6 ′-N-乙酰基转移酶I [AAC（6 ′）-I]，该酶修饰了阿米卡星和妥布霉素。虽然阿米卡星被乙酰化，但这种氨基糖苷类与头孢他啶对BM 2656的杀菌协同作用受到的影响最小。测定了DNA片段的序列。它含有一个aac（6 '）-Ib样基因，位于Tn 21相关保守区的下游。该aac（6 '）-Ib基因的翻译序列与粘质沙雷氏菌和肺炎克雷伯氏菌aac（6'）-Ib基因盒的推定产物具有99.2%的同源性，与铜绿假单胞菌aacA（6 '）-II基因的推定产物具有69%的同源性。我们的结论是aac（6 '）-Ib基因已经扩散到铜绿假单胞菌的染色体上，可能是通过转座。
Pseudomonas aeruginosa BM2656 was resistant to tobramycin and susceptible to gentamicin and amikacin by disk diffusion testing. This unusual resistance was not transferable by conjugation to Escherichia coli or P. aeruginosa PAO38, and plasmid DNA was not detected in this strain. A 0.9-kb fragment harboring the tobramycin resistance gene was cloned from BM2656 into pUC18, generating pAT129. Analysis for aminoglycoside-modifying activity in extracts of BM2656 and E. coli harboring pAT129 indicated that tobramycin resistance was due to synthesis of an aminoglycoside 6'-N-acetyltransferase type I [AAC(6')-I] enzyme which modified amikacin and tobramycin. Although amikacin was acetylated, the bactericidal synergism of this aminoglycoside with ceftazidime against BM2656 was minimally affected. The sequence of the DNA fragment was determined. It contained an aac(6')-Ib-like gene and was located downstream from a conserved region related to Tn21. The translated sequence of this aac(6')-Ib gene possessed 99.2% identity with the putative products of the aac(6')-Ib gene cassettes from Serratia marcescens and Klebsiella pneumoniae and 69% identity with the putative aacA(6')-II gene product from P. aeruginosa. We conclude that an aac(6')-Ib gene has spread to the chromosome of P. aeruginosa, probably by transposition.