Matar G M, Al Khodor S, El-Zaatari M, Uwaydah M
Department of Microbiology and Immunology, Faculty of Medicine, American University of Beirut, Lebanon.
Ann Trop Med Parasitol. 2005 Jun;99(4):413-7. doi: 10.1179/136485905X36235.
The prevalences of extended-spectrum beta-lactamases (ESBL) and their encoding bla genes, TEM, SHV and CTX_M, were investigated in isolates of Escherichia coli that were resistant to beta-lactam and/or non-beta-lactam antibiotics. Of the 250 E. coli isolates investigated, all of which came from patients in a major hospital in southern Lebanon, 61 (13.3%) were found to have ESBL, their production of beta-lactamase being confirmed by the ceftazidime and ceftazidime/clavulanic-acid disc methods. All 61 ESBL isolates were resistant to beta-lactams and sensitive to imipenem, piperacillin/tazobactam and cefoxitime. Only 40% were resistant to fluoroquinolones, 33% were resistant to aminoglycosides, and 18% were considered to have multi-drug resistance. The results of the PCR-based amplification of the bla gene in DNA samples from the 61 ESBL isolates indicated that 11 (18%) of the isolates carried both the TEM and SHV genes, 37 (61%) carried the TEM gene but not the SHV, and 13 (21%) had the SHV gene but not the TEM. None of the isolates carried the CTX_M gene. Of the 37 TEM-positive/SHV-negative isolates, 43% were resistant to fluoroquinolones and 37% to aminoglycosides. Increased resistance to non-beta-lactam antibiotics was observed in the isolates harbouring both the TEM and SHV genes, of which 54% were resistant to all of the tested antibiotics except imipenem, 36% were only resistant to fluoroquinolones, and 9.1% only resistant to aminoglycosides. The possibility that the concomitant presence of TEM- and SHV-type beta-lactamases is associated with resistance to non-beta-lactam antibiotics requires further research. The prevalences of ESBL and their encoding genes in Gram-negative bacteria collected from various regions in Lebanon will now be investigated.
在对β-内酰胺类和/或非β-内酰胺类抗生素耐药的大肠杆菌分离株中，研究了超广谱β-内酰胺酶（ESBL）及其编码bla基因（TEM、SHV和CTX_M）的流行情况。在研究的250株大肠杆菌分离株中，所有菌株均来自黎巴嫩南部一家大型医院的患者，发现61株（13.3%）具有ESBL，通过头孢他啶和头孢他啶/克拉维酸纸片法确认了它们的β-内酰胺酶产生情况。所有61株ESBL分离株均对β-内酰胺类耐药，对亚胺培南、哌拉西林/他唑巴坦和头孢西丁敏感。仅40%对氟喹诺酮类耐药，33%对氨基糖苷类耐药，18%被认为具有多重耐药性。对61株ESBL分离株的DNA样本进行基于PCR的bla基因扩增结果表明，11株（18%）分离株同时携带TEM和SHV基因，37株（61%）携带TEM基因但不携带SHV基因，13株（21%）携带SHV基因但不携带TEM基因。没有分离株携带CTX_M基因。在37株TEM阳性/SHV阴性分离株中，43%对氟喹诺酮类耐药，37%对氨基糖苷类耐药。在同时携带TEM和SHV基因的分离株中观察到对非β-内酰胺类抗生素的耐药性增加，其中54%对除亚胺培南外的所有测试抗生素耐药，36%仅对氟喹诺酮类耐药，9.1%仅对氨基糖苷类耐药。TEM型和SHV型β-内酰胺酶同时存在与对非β-内酰胺类抗生素耐药之间的关联可能性需要进一步研究。现在将对从黎巴嫩不同地区收集的革兰氏阴性菌中ESBL及其编码基因的流行情况进行调查。
