黏液型铜绿假单胞菌耐药性及β内酰胺酶耐药表型检测

The drug resistance and β lactamase phenotype detection of mucoid Pseudomonas aeruginosa

目的检测黏液型铜绿假单胞菌对常见抗生素的敏感性及其超广谱13内酰胺酶耐药表型的表达。方法标本接收后分别划线接种于不同平板进行细菌分离培养及鉴定，对分离出的黏液型铜绿假单胞菌进行药物敏感性检测，结果依据CLSI2013进行判断。药物敏感性检测采用K—B纸片扩散法，B内酰胺酶耐药表型检测采用Etest法。统计学方法采用SPSS19．0，不同产酶组间药物敏感性比较采用X2检验，P〈0．05为差异有统计学意义。结果黏液型铜绿假单胞菌对常见抗菌药物敏感率均在70％以上，其中阿米卡星、妥布霉素、庆大霉素、亚胺培南和美罗培南敏感率超过90％。C类头孢菌素酶（AmpC酶）阳性率28．3％（56／198），AmpC酶阳性株与阴性株相比，药物敏感性较低，哌拉西林／他唑巴坦、阿米卡星、头孢他啶、环丙沙星、左氧氟沙星和氨曲南对抗菌药物敏感率差异均有统计学意义（X2=3．89～14．45，P均〈0．05）；超光谱13内酰胺酶（ESBLs）阳性率10．6％（21／198），ESBLs阳性株头孢他啶和氨曲南敏感率[分别为42．9％（9／21）和57．1％（12／21）]与阴性株[分别为73．5％（130／177）和72．3％（128／177）]相比，差异有统计学意义（x2=5．06和19．24，P均〈0．05），对其他抗生素敏感率差异无统计学意义（X2=0．01—3．47，P均〉0．05）；金属p内酰胺酶（MBL）阳性率19．7％（39／198），除庆大霉素和氨曲南外MBL阳性株对常见抗生素敏感率均低于阴性株（X2=4．07—15．99，P均〈0．05）；所有检测株均为肺炎克雷伯菌碳青霉烯酶（KPC）阴性。结论黏液型铜绿假单胞菌对常见抗生素敏感性较高，但产酶株对某些抗生素敏感性较差，临床医生应根据实验室结果及时调整用药。

Objective To investigate the drug sensitivity of mucoid Pseudomonas aeruginosa to common antibiotics and the expression of β-1actamase-resistant phenotype. Methods The specimens were inoculated onto different disks to isolate and cultivate bacteria. The antibiotic susceptibility of mucoid Pseudomonas aeruginosa isolates was detected and judged by CLSI 2013. The detection of drug resistance was done by Kirby-Bauer （K-B） method and β lactamase-resistant phenotype was detected by E-test. SPSS19. 0 was used to statistic data and X2 test was used to compare the antibiotic susceptibility between different groups. For all statistical test, a P values less than 0. 05 was defined as statistically significant. Results The susceptibilities of mucoid Pseudomonas aeruginosa to the regular antibiotics were above 70% , of which the sensitivities to amikacin, to bramycin, gentamicin, imipenem and meropenem were higher than 90%. The positive rate of ampler class C β-1actamase （AmpC） was 28.3% （56/198）. The drug sensitivity of positive strains was lower than that of the negative strains, and the differentiation was significant to piperacillin-tazobactam, amikacin, ceftazidime, levofloxaein, ciprofloxacin and aztreonam （X2 = 3.89 - 14. 45, all P 〈0. 05 ）. The positive rate of extended spectrum β-1actamase（ESBLs） was 10. 6% （21/198）. The drug sensitivity to ceftazidime and aztreonam of positive strains [ 42. 9% （9/21）and 57.1% （12/21） , 2 respectively]. It was lower than that of the negative strains[73.5% （ 130/177 ） and 72.3% （128/177） 1 , X2= 5.06 and 19. 24, both P 〈 0. 05. The difference of the other antibiotics was not significant （ ~2 = 0. 01 - 3.47, all P 〉0. 05）. The positive rate of metallo-^-lactamase （MBL） was 19.7% （39/198）, and the drug susceptibility of positive strains was lower than that of negative strains except gentamicin and aztreonam（ X2 = 4.07 - 15.99, all P 〈 0. 05）. All the detected strains were Klebsiella pneumonia carbapenemase （ KPC ） negative. Conclusions The antibiotic susceptible rate of mucoid Pseudomonas aeruginosa was high, but some enzyme-produced strains were lower. The clinician should adjust medicine program by the results of laboratory.