Extended spectrum beta-lactamases in Escherichia coli & Klebsiella pneumoniae & associated risk factors.
Extended spectrum beta-lactamases in Escherichia coli & Klebsiella pneumoniae & associated risk factors.
复制标题
大肠杆菌中的超广谱 β-内酰胺酶
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
A. Ayyagari
中科院分区：
文献类型：
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作者：
A. Goyal;K. Prasad;A. Prasad;Sapna Gupta;Ujjula Ghoshal;A. Ayyagari
背景与目的
超广谱β-内酰胺酶（ESBLs）已成为全球范围内的主要威胁，治疗选择有限。在印度，产ESBL菌株的基因型在很大程度上仍是未知的，因此本研究的目的是确定大肠埃希菌和肺炎克雷伯菌中ESBL的发生率，其分子类型和相关的危险因素在三级医院。
方法
共收集200株临床分离的大肠埃希菌。coli（n=143）和K.对2006年2月至7月在印度北部的一家三级保健医院Sanjay Gandhi医学科学研究生院收集的57例肺炎链球菌（n=57）进行ESBL产生的表型检查。用特异性引物对ESBL菌株进行bla（TEM/SHV/CTX-M）基因分型。通过限制性内切酶分析确定bla（CTX-M）簇，并通过PCR产物测序确定基因型。还研究了对其他抗菌剂的耐药性。用Logistic回归分析ESBL感染的各种危险因素。
结果
ESBLs检出率为63.6%。大肠杆菌和K.肺炎分离株。大多数可分型菌株携带两种或两种以上的ESBL基因（57.3%）。总的来说，bla（CTX-M）是最常见的基因型（85.4%），其次是bla（TEM）（54.9%）和bla（SHV）（32.9%），无论是单独还是联合使用。所有CTX-M酶在E.大肠埃希菌和克雷伯氏菌的阳性率为87.5%。pneumoniae属于CTX-M-1簇。对随机选择的20个bla（CTX-M）PCR产物进行测序，并且全部鉴定为CTXM- 3。ESBL菌株对其他抗生素的耐药率依次为阿米卡星14.7%、庆大霉素66.7%、甲氧苄啶/磺胺甲恶唑79.1%、环丙沙星93.8%。单因素分析显示，既往抗生素暴露、静脉输液器和导尿管使用、肾功能不全和ICU入院与ESBL感染相关。在多变量分析中，抗生素暴露（P=0.001）和导尿管使用（P<0.001）是ESBL感染的危险因素。
解释和结论
我们的研究表明ESBL的发生率很高，CTX-M是我院的新兴类型，CTX-M-3在印度首次报道。对其他非β-内酰胺类抗生素的高共耐药性是ESBL感染管理的主要挑战。
BACKGROUND & OBJECTIVE
Extended spectrum beta-lactamases (ESBLs) have emerged as a major threat worldwide with limited treatment options. The genotypes of ESBL producing strains largely remain unknown in India; hence the present study was aimed to determine the occurrence of ESBLs in Escherichia coli and Klebsiella pneumoniae, their molecular types and associated risk factors in a tertiary care hospital.
METHODS
Total 200 consecutive clinical isolates of E. coli (n=143) and K. pneumoniae (n=57) collected between February and July 2006 at Sanjay Gandhi Postgraduate Institute of Medical Sciences, a tertiary care hospital in north India, were examined phenotypically for ESBL production. ESBL strains were further typed for the bla(TEM/SHV/CTX-M) genes by PCR using specific primers. The bla(CTX-M) cluster was identified by restriction analysis and genotype by sequencing of PCR product. Resistance to other antimicrobial agents was also studied. Various risk factors associated with ESBL infections were analyzed by logistic regressions.
RESULTS
ESBLs were found in 63.6 per cent E. coli and 66.7 per cent K. pneumoniae isolates. Majority of the typeable isolates harboured two or more ESBL genes (57.3%). Overall bla(CTX-M) was the commonest genotype (85.4%) followed by bla(TEM) (54.9%) and bla(SHV) (32.9%) either alone or in combination. All CTX-M enzymes in E. coli and 87.5 per cent in K. pneumoniae belonged to the CTX-M-1 cluster. Sequencing was done for randomly selected 20 bla(CTX-M) PCR products and all were identified as CTXM- 3. Resistance of ESBL isolates to other antibiotics was amikacin 14.7 per cent, gentamicin 66.7 per cent, trimethoprim/sulphamethoxazole 79.1 per cent and ciprofloxacin 93.8 per cent. Prior antibiotic exposure, use of intravenous device and urinary catheter, renal insufficiency and ICU admission were associated with ESBL infection on univariate analysis. On multivariate, antibiotic exposure (P=0.001) and use of urinary catheter (P<0.001) were identifified as risk for ESBL infection.
INTERPRETATION & CONCLUSION
Our study showed high ESBL occurrence with CTX-M as the emerging type in our hospital and CTX-M-3 being reported for the fi rst time in India. High co-resistance to other non-beta-lactam antibiotics is a major challenge for management of ESBL infections.