铜绿假单胞菌中Ambler A和D类酶流行状况与药物敏感性研究

Prevalence of Ambler Class A and D β-lactamase and Drug Susceptibility of Pseudomonas aeruginosa

目的了解Ambler A和D类β-内酰胺酶在铜绿假单胞菌(PA)的流行状况及其与药物敏感性的关系。方法用琼脂稀释法检测101株铜绿假单胞菌对8种常用抗菌药物的最低抑菌浓度,并PCR测序法鉴定101株铜绿假单胞菌中Ambler A和D类β-内酰胺酶流行状况。结果101株铜绿假单胞菌对8种常用药物的MIC50的范围为232μg/ml。最有效的药物是美罗培南,但也仅能抑制80·2%的菌株。1种或1种以上β-内酰胺酶基因阳性的有27株,其中tem-1型是最常见的亚型,共有14株菌阳性;有10株菌oxa-10基因阳性;菌株PA36的oxa-Ⅰ群酶基因在基因库中无完全同源序列,将其暂命名为oxa-56like,并已提交基因库,序列号为EF437948。结论铜绿假单胞菌对β-内酰胺类耐药现象非常普遍,产酶株有对广谱抗菌药物广泛耐药的趋势。因此,早期及时地检出产酶菌株对临床治疗中抗菌药物的选择和控制感染的播散都是非常重要的。

Objective To understand prevalence of Ambler class A and D β-1actamase and drug resistance in Pseudomonas aeruginosa. Method The minimum inhibitory concentrations（MICs） of 8 kinds of drugs for 101 P. aeruginosa isolates were determined by the agar dilution method. Ten kinds of Ambler class A and D β-1actamase genes were identified by PCR-sequencing. Result The MIC50 of 8 antimicrobials to 101 isolates P. aeruginosa ranged from 2 to 32μg/ ml. The most effective antimicrobial agent was meropenem, but it could only inhibit 80. 2% of the P. aeruginosa strains tested in this study. 27 isolates harbored one or more kinds of β -1actamase genes, in which tern-1 （ 14 strains, 13.9% ） was the most frequently and oxa-10（^-10 strains, 9.9% ） was the second. The oxa-I group gene frangment of PA36 had no 100% identity corresponding sequence in GenBank. This gene frangment was named oxa-56 like and has been submitted to GenBank. The accession number is EF437948. Conclusion Resistance of P. aeruginosa to β-1actams seems very common Xijing Hospital. The early recognition of β-lactamase producers is critical for antimicrobial agents selection in the treatment of clinical infection and for the prevention of their widespread dissemination