摘要
目的对儿童携带214株卡他莫拉菌分离株产酶率和9种抗生素敏感性测定,研究产酶株β-内酰胺酶耐药基因特征。方法采用英国抗生素化疗学会(BSCA)琼脂稀释法进行抗生素最小抑菌浓度测定;用Nitrocefin纸片琼脂扩散法检测β- 内酰胺酶;PCR扩增结合限制性内切酶分析方法对分离株进行bro基因分型。结果214株卡他莫拉菌中β-内酰胺酶产酶率为94.4%。产酶株对β-内酰胺类抗生素:氨苄西林、头孢呋辛、头孢克洛的MlC90分别为32 mg/L、2 mg/L和8 nag/L,明显高于非产酶株的0.5 mg/L,10 mg/L和0.5 mg/L;产酶株对氨苄西林、头孢呋辛、头孢克洛耐药率分别为95%、46.5%和76 2%,明显高于非产酶株组(0%)(x2=100.889,8.159,28.961 P均<0 001);产酶株与非产酶株组对头孢噻肟、非β-内酰胺类抗生素红霉素、环丙沙星、氯霉素和四环素敏感性无显著差异,其总体敏感性分别为100%、95.8%、100%、100%、34.1%,所有分离株对复方磺胺甲(口恶)唑产生耐药(100%),MIC50和MIC90高达32 mg/L和128 mg/L。202例产酶株经bro基因分型,69.8%(141/ 202)为bro—Ⅰ型,30.2%(61/202)为bro-Ⅱ型。bro-Ⅰ型携带菌株对β-内酰胺类抗生素的MIC50和MIC90高于bro-Ⅱ型的耐药株。结论北京地区携带的卡他莫拉菌β-内酰胺酶产酶率较高。
Objective To determine the beta-lactamase producing rate and susceptibility of nine antibiotics of 214 Moraxella Catarrhalis isolates carried by children and to investigate the characteristics of beta-lactamase resistant gene. Methods British Society for Antimicrobial Chemotherapy (BSAC) disk diffusion test and agar dilution test were taken to determine minimal inhibition concentration (MIC) and antibiotic resistance of Mc strains Nitrocefin disk test was used to detect beta-lactamase producing. PCR combining restriction endonuclease analysis was employed to do the bro genotyping. Results Among 214 strains, 94. 4% of them produced the beta-lactamase. The beta-lactamase producing isolates had the MIC90 32 mg/L for ampicillin, 2 mg/L for cefuroxime, and 8 mg/L for cefaclor, which were higher than the non beta-lactamase producing isolates 0. 5 mg/L, 1.0 mg/L and 0 5 mg/L respectively The resistant rates of beta-lactamase producing isolates were 95% for ampicillin, 46. 5% for cefuroxime, and 76 2% for cefaclor, which were also higher than non beta-lactamase producing isolates (0). There was no significant difference between beta-lactamase producing isolates and non beta-lactamase producing isolates in the susceptibility for cefotaxime, erythromycine, ciprofloxacin, tetracycline and chloramphenicol, with total susceptibility rates of 100% , 95 8% , 100% , 34.1 % and 100% , respectively. All of the isolates in this study were resistant to cotrimoxazole. 69.8% (141/202) of beta-lactamase producing isolates had bro-Ⅰ and 30. 2% (61/202) bro Ⅱ The isolates carrying gene of bro-Ⅰ had higher MIC50 and MIC90 than bro- Ⅱ strains. Conclusions There is high prevalence of beta-lactamase producing Moraxella Catarrhalis in Beijing children. Those isolates have high resistant rates to ampicillin. The dominant genotype for beta-lactamase producing isolates is bro-Ⅰ. The isolates carrying bro-Ⅰ gene are strongly resistant to beta-lactamase antibiotics than that carrying bro- Ⅱ gene.
出处
《实用儿科临床杂志》
CAS
CSCD
北大核心
2005年第5期423-426,共4页
Journal of Applied Clinical Pediatrics
基金
国家自然科学基金项目资助(30271377)
国家科技攻关计划项目资助(2003BA712A11-20)
