Dağlar Duygu, Ongüt Gözde, Oğünç Dilara, Ozhak Baysan Betil, Demirbakan Hadiye, Sepin Özen Nevgün, Gültekin Meral
Akdeniz Üniversitesi Tıp Fakültesi, Tıbbi Mikrobiyoloji Anabilim Dalı, Antalya, Türkiye.
Mikrobiyol Bul. 2010 Jul;44(3):367-74.
The aim of this study was to determine the extended-spectrum beta-lactamase (ESBL) types by isoelectric focusing (İEF) and polymerase chain reaction (PCR) methods in 56 Escherichia coli strains isolated from urine samples of patients with community-acquired urinary tract infection and determined as ESBL positive with the phenotypic screening tests (E test and combined disk method). IEF revealed that most of the strains produced 1 to 3 different bands, mostly at the isoelectric points 8.2 (n= 44, 79%) compatible with CTX-M. Twenty four (43%) isolates had CTX-M and TEM enzyme bands together, 16 (29%) isolates had only CTX-M enzyme bands, 3 (5%) isolates had CTX-M, TEM, SHV bands, one had CTX-M and SHV enzyme bands together, and one had only TEM band. Eleven E.coli strains did not yield any enzyme bands. PCR analysis revealed that 93% (n= 52) of the isolates had CTX-M, 64% (n= 36) had TEM and 11% (n= 6) had SHV, while 29 (52%) had CTX-M + TEM, three had CTX-M + SHV, and three had CTX-M + TEM + SHV genes together. PER-1 type beta-lactamases were not detected by PCR method. PCR analysis of the eleven strains that yielded no band in IEF showed that 5 strains had CTX-M + TEM, 3 had CTX-M and 3 had TEM enzyme genes. The consistency between IEF and PCR methods for the determination of CTX-M, TEM and SHV enzymes was 85%, 78% and 67%, respectively. Genes encoding ESBL's are usually located on transferrable plasmids that may also carry other resistance determinants. Thus detection of beta-lactamase enzyme types in ESBL positive bacteria is important for the choice of appropriate antimicrobial agents for treatment.
本研究的目的是通过等电聚焦（IEF）和聚合酶链反应（PCR）方法，对从社区获得性尿路感染患者尿液样本中分离出的56株大肠埃希菌进行超广谱β-内酰胺酶（ESBL）类型测定，这些菌株经表型筛选试验（E试验和复合纸片法）确定为ESBL阳性。IEF显示，大多数菌株产生1至3条不同的条带，主要在与CTX-M兼容的等电点8.2处（n = 44，79%）。24株（43%）分离株同时具有CTX-M和TEM酶条带，16株（29%）分离株仅有CTX-M酶条带，3株（5%）分离株具有CTX-M、TEM、SHV条带，1株同时具有CTX-M和SHV酶条带，1株仅有TEM条带。11株大肠埃希菌未产生任何酶条带。PCR分析显示，93%（n = 52）的分离株具有CTX-M，64%（n = 36）具有TEM，11%（n = 6）具有SHV，而29株（52%）同时具有CTX-M + TEM，3株具有CTX-M + SHV，3株同时具有CTX-M + TEM + SHV基因。PCR方法未检测到PER-1型β-内酰胺酶。对在IEF中未产生条带的11株菌株进行PCR分析显示，5株具有CTX-M + TEM，3株具有CTX-M，3株具有TEM酶基因。IEF和PCR方法在测定CTX-M、TEM和SHV酶方面的一致性分别为85%、78%和67%。编码ESBL的基因通常位于可转移质粒上，这些质粒也可能携带其他耐药决定子。因此，检测ESBL阳性细菌中的β-内酰胺酶类型对于选择合适的抗菌药物进行治疗很重要。
