儿童重症监护室产超广谱β-内酰胺酶肺炎克雷伯菌的耐药基因及其流行病学特征

Studies on the drug-resistance genes and its epidemiology of the strains produced extended spectrum β-lactamases of Klebsiella pneumoniae in Pediatric Intensive Care Unit

目的 了解贵阳市儿童医院儿科重症监护室（PICU）产超广谱β-内酰胺酶（ESBLs）肺炎克雷伯菌感染的耐药基因型及其分子流行病学特征.方法 采用纸片扩散法和自动化仪器对临床分离菌株作用药敏试验,ESBLs表型确认试验采用双纸片协同法,采用PCR法检测耐药基因.结果 2013年4月至12月住院患儿分离出44株非重复肺炎克雷伯菌,检出产ESBLs肺炎克雷伯菌共29株,阳性率达65.9％.29株产ESBLs肺炎克雷伯菌对碳青酶烯类、头霉素类及喹诺酮类高度敏感,对青霉素类和第一、二代头孢菌素类耐药率均为100％;15株非产ESBLs肺炎克雷伯菌株仅对青霉素类耐药率达100％.产ESBLs肺炎克雷伯菌对9种抗生素耐药率（氨苄西林/舒巴坦79.3％、头孢唑啉100.0％、头孢呋辛100.0％、头孢孟多100.0％、头孢曲松100.0％、头孢他啶79.3％、头孢吡肟65.5％、庆大霉素41.4％、氨曲南79.3％）明显高于与非产ESBLs菌株（氨苄西林/舒巴坦13.3％、头孢唑啉6.7％、头孢呋辛20.0％、头孢孟多20.0％、头孢曲松0、头孢他啶0、头孢吡肟0、庆大霉素6.7％、氨曲南0）（x2=17.54、35.51、28.00、28.00、44.00、24.93、17.30、4.18、24.93,P均＜0.05）.29株产ESBLs肺炎克雷伯菌共检出3种ESBLs耐药基因,检出率最高的是SHV型[93.1％（27/29株）],其次是TEM型和CTX-M型,分别占51.7％（15/29株）和37.9％（11/29株）.29株产ESBLs肺炎克雷伯菌基因型分布有5种形式：14株携带单一ESBLs基因,占48.3％;5株同时携带2种基因型,占17.2％;9株携带3种基因型,占31.0％;1株未能分型.结论 产ESBLs肺炎克雷伯菌已在贵阳市儿童医院PICU广泛流行,且具有多重耐药性,其耐药基因型已出现多样化的特征.

Obgective To explore the antimicrobial resistance genotypes and molecular epidemic features of Klebsiella pneumoniae （K.pneumoniae） producing extended spectrum 3-lactamases （ESBLs） in the Pediatric Intensive Care Unit （PICU） of Guiyang Children＆#39; s Hospital.Methods Disc diffusion technique （Kirby-Bauer method） and automatic microbiology analysis system were employed to determine the antimicrobial resistance,and Double-disk Diffusion was adopted in the phenotype confirmatory test of ESBLs,and PCR was used to determine the antimicrobial resistance genotypes.Results Among 44 straits of non-repetitive-K.pneumoniae,isolated from the children during hospitalization since April to December of 2013,29 straits （65.9%） were detected.The findings of sensitivity tests showed that 29 strains of ESBLs-producing K.pneumoniae presented a higher rate of sensitivity to carbapenems,cephamycin and quinolones,100% resistance to penicillin and cephalosporins of the first and the second generations.Fifteen non-ESBLs-producing K.pneumoniae presented 100% resistance to penicillin.The rate of resistance to 9 kinds of antibiotics （Ampicillin/Sulbactam,Cefazolin,Cefuroxime,Cefamandole,Cefiriaxone,Ceftazidime,Cefepime,Gentamicin,Aztreonam） in ESBLs-producing K.pneumoniae strains（79.3%,100.0%,100.0%,100.0%,100.0%,79.3%,65.5%,41.4%,79.3%） was significantly higher than that of non-ESBLs-producing K.pneumoniae trains （13.3%,6.7%,20.0%,20.0%,0,0,0,6.7%,0） （x2 =17.54,35.51,28.00,28.00,44.00,24.93,17.30,4.18,24.93,all P 〈 0.05）.In 29 strains of ESBLs-producing K.pneumoniae,3 genotypes were detected respectively：93.1% of SHV （27/29 strains）,51.7 % of TEM （15/29 strains） and 37.9 % of CTX-M （11/29 strains）.Five forms of genotype distribution were presented：14 （43.8%） strains carrying single ESBLs gene,5 （17.2%） strains carrying 2 types,19 （31.0%） strains carrying 3 types,and 1 strain had not been genotyped.Conclusions ESBLs-producing K.pneumoniae had been epidemic in PICU of Guiyang Children＆#39;s Hospital,with multiple antimicrobial resistances and diversification of antimicrobial resistance genotypes.