儿童感染菌中1913株产超广谱β-内酰胺酶型别特点及耐药性研究

The characteristics and anti-microbial resistance of extended-spectrum β-lactamases type in 1 913 strains of pathogenic bacteria isolated from children

目的研究武汉地区住院患儿感染菌中产超广谱β-内酰胺酶(ESBLs)的基因型及耐药性。方法应用MICs试验和PCR方法,研究武汉地区住院患儿及ICU病房收集的2258株E.coli和1129株K.pneumoniae产ESBLs的发生率、可能的基因型及耐药性。结果产ESBLs的E.coli和K.pneumoniae的发生率分别为60.2%(1360/2258)和49.0%(553/1129)。RAPD分析显示一些不同的产ESBLs的菌株具有相同的RAPD型别,而不同的RAPD型别的菌株可能含有相同的产ESBLs的基因型。这些菌株耐受绝大部分的β-lactams(包括第三代头孢菌素)和non-β-lactams(如氨基糖苷、四环素和氯霉素),几乎所有的产ESBLs菌株对亚氨培南、头孢美唑和β-内酰胺抗生素/克拉维酸敏感。TEM是产ESBLs的主要基因型,CTX-M型也常见,其中以CTX-M-3为主。产ESBLs一些E.coli和大部分的K.pneumoniae的菌株含有不止一个ESBLs的基因型。产ESBLs菌株的传播绝大部分依赖质粒的水平转移。结论武汉地区分离到的E.coli和K.pneumoniae菌株产ESBLs很常见,因此对这些菌株进行监测并阻止其传播具有重要意义。[临床儿科杂志,2009,27(6):540-544]

Objective To study the genotype distribution and antibiotic resistance of extended-spectrum β, lactamases （ESBLs） in Wuhan city. Methods Prevalence, resistance, and probable genotype of ESBLs were investigated with MICs testing and polymerase chain reaction in 2 258 Escherichia coli and 1 129 KlebsieUae pneumoniae isolates collected from hospitalized patients in Wuhan region. Results The incidence of ESBLs-producing strains was 49.0% among Klebsiellae pneumoniae （553/1 129） and 60.2% among Eseherichia coli （1 360/2 258）, most of them were collected from patients in intensive care unit. RAPD analysis showed that different ESBLs-producing strains possessed the same RAPD type, whereas different RAPD type strains contained the same ESBLs genotype. These strains were resistant to most β-laetams （including the third-generation cephalosporins）and non-β-lactams （such as aminoglycosides, tetracycline and chloramphenicol）. All or most ESBLs producers were susceptible to imipenem, cefmetazole and β-lactam/clavulanic acid. TEM was the main type of ESBLs, and CTX-M type was common （among the latter mainly CTX-M-3 subtype） based on DNA sequencing in these isolates. Some ESBLs-producing Escherichia coli and most ESBLs-producing Klebsiellae pneumoniae produced more than one type of β-lactamase. The spread of these ESBLs was mainly mediated by plasmid transfer. Conclusions These data confirmed that ESBLs producers are common among hospital strains of Escherichia coli and Klebsiellae pneumoniae in Wuhan. It is important to monitor such strains closely and prevent their spread.