Feizabadi Mohammad Mehdi, Shokrzadeh Leila, Sayady Sara, Asadi Soroor
Department of Microbiology, School of Medicine, Medical Sciences, University of Tehran, Tehran, Iran.
Can J Microbiol. 2008 Oct;54(10):887-90. doi: 10.1139/w08-073.
Infections with high levels of gentamicin-resistant (HLGR) isolates of Enterococcus faecalis are common in Tehran hospitals. Genes encoding such resistance are transmissible by conjugation at high frequency. The purpose of this study was to determine the existence of Tn5281 and its flanking aminoglycoside modifying enzyme gene aac(6')-aph(2") among 102 HLGR isolates of E. faecalis cultured from patients at three hospitals in Tehran, Iran. These isolates were detected by disks containing 120 microg of gentamicin and made 65% of all E. faecalis during the study period. DNA was extracted from HLGR isolates and subjected to PCR assays targeting aac(6')-aph(2") and conjugative transposon Tn5281. The amplified aac(6')-aph(2") gene was labeled with digoxigenin and probed with Tn5281 amplicons in dot blot hybridization assays. The aac(6')-aph(2") gene was detected in 91%-92% (n = 93) of the HLGR isolates. All isolates containing aac(6')-aph(2") were positive in long-PCR targeting Tn5281 and the probe hybridized with Tn5281 amplicons. The number of HLGR isolates of E. faecalis has increased considerably in Tehran hospitals. Tn5281 is the main cause of transmission of aac(6')-aph(2") to different isolates of E. faecalis in the hospitals studied.
在德黑兰的医院中，粪肠球菌高水平庆大霉素耐药（HLGR）菌株感染很常见。编码这种耐药性的基因可通过接合高频传播。本研究的目的是确定在伊朗德黑兰三家医院从患者中培养的102株粪肠球菌HLGR菌株中Tn5281及其侧翼氨基糖苷修饰酶基因aac(6')-aph(2")的存在情况。这些菌株通过含120微克庆大霉素的纸片检测，在研究期间占所有粪肠球菌的65%。从HLGR菌株中提取DNA，并进行针对aac(6')-aph(2")和接合转座子Tn5281的PCR检测。扩增的aac(6')-aph(2")基因用地高辛标记，并在斑点杂交试验中用Tn5281扩增子进行探针检测。在91%-92%（n = 93）的HLGR菌株中检测到aac(6')-aph(2")基因。所有含有aac(6')-aph(2")的菌株在针对Tn5281的长PCR中呈阳性，且探针与Tn5281扩增子杂交。在德黑兰的医院中，粪肠球菌HLGR菌株的数量显著增加。Tn5281是在所研究医院中aac(6')-aph(2")传播到不同粪肠球菌菌株的主要原因。
