García José, Martínez Dianny, Caña Luisa, González Diorelis, Rodríguez Lucy, Rodulfo Hectorina, Donato Marcos De, Guzmán Militza
Laboratorio de Bacteriología, Hospital Universitario "Antonio Patricio de Alcalá", Cumaná, Venezuela.
Laboratorio de Genética Molecular, Instituto de Biomedicina y Ciencias Aplicadas Dra. "SusanTai", Cumaná, Venezuela.
Rev Chilena Infectol. 2018 Apr;35(2):147-154. doi: 10.4067/s0716-10182018000200147.
Enterobacteria resistant to quinolones is increasing worldwide, including Venezuela. The mechanism for this resistance could be due to genes included in the chromosome or in transmissible plasmids.
To evaluate the resistance to quinolones, coded by qnr genes present in enterobacteria species, isolated in the University Hospital of Cumana, Venezuela.
Antimicrobial susceptibility tests to quinolones, beta-lactams and aminoglycosides were carried out to all the isolates. The presence of qnr genes were determined by PCR. The isolates carrying the qnr genes were used for bacterial conjugation tests to determine the presence of transferable plasmids. Antimicrobial susceptibility tests and PCR were carried out in the transconjugants to verify the transfer of the genes.
High levels of antimicrobial resistance to quinolones and beta-lactams were found among the isolates. We found that 33.6% of the isolates carry the qnrB gene and 0.9% qnr A gene. Of the 23 transconjugants, 20 showed to have qnrB gene, but none qnrA.
We concluded that the high frequency of qnr genes found in the enterobacteria isolates and their presence on transferable plasmids, complicate the use of quinolones for the treatment of bacterial infections, thus, a treatment plan should be designed with the rational use and the rotation of different types of antimicrobials, in order to avoid the selection of increasingly resistant strains.
包括委内瑞拉在内，全球范围内对喹诺酮类耐药的肠杆菌正在增加。这种耐药机制可能归因于染色体或可传递质粒中包含的基因。
评估委内瑞拉库马纳大学医院分离出的肠杆菌属物种中由qnr基因编码的对喹诺酮类的耐药性。
对所有分离株进行了对喹诺酮类、β-内酰胺类和氨基糖苷类的药敏试验。通过聚合酶链反应（PCR）确定qnr基因的存在。携带qnr基因的分离株用于细菌接合试验以确定可转移质粒的存在。在接合子中进行药敏试验和PCR以验证基因的转移。
在分离株中发现对喹诺酮类和β-内酰胺类有高水平的耐药性。我们发现33.6%的分离株携带qnrB基因，0.9%携带qnrA基因。在23个接合子中，20个显示有qnrB基因，但没有qnrA基因。
我们得出结论，在肠杆菌分离株中发现的qnr基因的高频率及其在可转移质粒上的存在，使喹诺酮类用于治疗细菌感染变得复杂，因此，应设计一个合理使用和轮换不同类型抗菌药物的治疗方案，以避免选择耐药性越来越强的菌株。
