老年人肺炎克雷伯菌耐药性和β-内酰胺酶基因分析

β-lactamase Genes and Drug Resistance of Klebsiella Pneumoniae Isolated from old Patients

目的分析老年人肺炎克雷伯菌的耐药谱及其携带的β-内酰胺酶基因。方法抗菌药物敏感试验采用微量肉汤稀释法测定临床分离的肺炎克雷伯菌对抗菌药物的耐药性,采用PCR法检测β-内酰胺酶耐药基因型。结果20株肺炎克雷伯菌对阿莫西林、替卡西林、哌拉西林、头孢噻吩、头孢他啶、头孢吡肟的耐药率均为100%,复方阿莫西林60%、头孢西丁40%、复方哌拉西林30%。PCR扩增后有19株均发现有产酶基因,阳性率为95%,最多的一株有4种基因。基因型主要是TEM型,20株中有19株为TEM型,少数为CTX-M型。结论肺炎克雷伯菌株大多携带β-内酰胺酶耐药基因,其对β-内酰胺类的高耐药率与TEM型基因有关。

Objective To investigate the drug resistance and β- laetamase genes of Klebsiella pneumoniae isolated from old patients. Methods Broth microdilution antimicrobial susceptibility test was performed. Drug resistance genes encoding β- lactamase were detected by PCR amplification and verified by DNA sequencer. Results The resistance rates of 20 strains of K . pneumoniae to amoxicillin, ticarcillin, piperacillin, cephalothin, ceftazidime and cefepime were all 100%. The resistance rates to amoxicillin/clavulanate, cefoxitin and piperacillin/tazobactam were 60%, 40% and 30% , respectively. 19 out of 20 strains of K. pneurnoniae contained β- lactamase genes, and the positive rate was 95%. One strain was even found with 4 kinds of β- lactamase genes. Most of the genes belonged to type TEM （ 19 out of 20） , and only a few belonged to CTX - M. Conclusion Most of the K. pneumoniae carried β- lactamase genes. The high resistance to β- lactam antibiotics of K. pneumoniae may have close relationship with TEM genes.