铜绿假单胞菌耐药性分析及耐药基因检测

Antimicrobial resistance and resistant genes of Pseudomonas aeruginosa

目的观察杭州市第一人民医院临床分离的铜绿假单胞菌的耐药性变迁及相关耐药基因。方法采用WHONET软件对2003-2007年临床分离的1489株铜绿假单胞菌的药物敏感性试验结果进行统计分析；用琼脂稀释法测定11种抗菌药物对36株多药耐药铜绿假单胞菌的最低抑菌浓度（MIC）；用PCR法检测β-内酰胺酶、氨基糖苷类修饰酶等编码基因，并对PCR扩增产物进行测序分析。结果铜绿假单胞菌对氨曲南、亚胺培南、头孢他啶、头孢吡肟、哌拉西林、哌拉西林／他唑巴坦、头孢哌酮／舒巴坦、环丙沙星、左氧氟沙星、庆大霉素和阿米卡星的耐药率由2003年的13．4％、10．6％、8．7％、7．9％、12．7％、12．7％、6．7％、15．8％、20．5％、24．7％和10．9％分别增至2007年的35．3％、40．9％、18．4％、32．4％、32．9％、32．0％、21．9％、37．8％、38．6％、39．4％和34．8％；11种抗菌药物对多药耐药铜绿似单胞菌的MIC90均≥128μg/mL。36株多药耐药铜绿假单胞菌中，β-内酰胺酶编码基因阳性占58．3％（21／36），氨基糖苷类修饰酶基因阳性占88．9％（32／36），oprD2基因缺失率为80．6％（29／36）。结论铜绿假单胞菌对常用抗菌药物的耐药率呈增高趋势，多药耐药情况严重，临床上应给予高度重视。多药耐药铜绿假单胞菌携带多种β-内酰胺酶编码基因及氨基糖苷类修饰酶基因，oprD2基因的缺失率高。

Objective To investigate the trend of antimicrobial resistance and the prevalence of resistant genes in Pseudomonas aeruginosa strains isolated from Hangzhou First People＇ s Hospital. Methods Antimicrobial susceptibilities of 1489 Pseudomonas aeruginosa strains isolated from 2003 to 2007 were statistically analyzed using WHONET. MICs of 11 antimierobials to 36 multi-drug-resistant Pseudomonas aeruginosa strains were determined by agar dilution method. Genes of β-lactamases （BLA） and aminoglycoside-modifying enzymes （AMEs） were detected by PCR and the PCR products were sequenced. Results The resistant rates to aztreonam, imipenem, ceflazidime, cefepime, piperaeillin, piperaeillin/ tazobaetam, cefoperazone/sulbactam, ciprufloxaein, levofloxacin, gentamicin and amikacin were increased from13.4%, 10.6%,8.7%,7.9%, 12.7%, 12.7%,6.7%, 15.8%,20.5% , 24. 7% and 10.9% in 2003 to 35.3% , 40. 9%, 18.4% , 32.4% , 32.9% , 32.0%, 21.9% , 37.8% , 38. 6% , 39.4% and 34. 8% in 2007, respectively. High MICs of 11 antimicrobials for muhi-drug resistant Pseudomonas aeruginosa were determined with MIC90 ≥ 128 μg/mL. In 36 multi-drug resistant Pseudomonas aeruginosa strains, 21 （58.3%） strains carried β-lactamase genes and 32 strains （88.9%） carried aminoglyeosidemodifying enzyme genes, while the deletion rate of oprD2 was 80. 6% （29/36）. Conclusions The resistant rates to common antibiotics of Pseadomonas aerugiaosa have increased, resulting in multi-drug resistance. Genes of β-lactamases and aminoglycoside-modifying enzymes are prevalent in multi-drug resistant Pseudomonas aeruginosa strains, with the common deletion of oprD2.