González-Abad Ma José, Alonso-Sanz Mercedes
Mª José González-Abad, Hospital Infantil Universitario Niño Jesús, Avda. Menéndez Pelayo, 65, 28009 Madrid, Spain.
Rev Esp Quimioter. 2015 Feb;28(1):36-8.
Decreased susceptibility to fluoroquinolones in Salmonella spp. may lead to treatment failures. The use of ciprofloxacin for extraintestinal and serious intestinal Salmonella infections in children is controversial and therefore the clinical relevance of these strains is not significant. Consequently little is know about the quinolone resistance of strains Salmonella of our paediatric population. The objective of this study was to assess the incidence of nonclassical quinolone resistance phenotype in paediatric patients.
Two hundred and sixty eight Salmonella spp. from Hospital Infantil Universitario Niño Jesús of Madrid (2009-2013) were tested against nalidixic acid and ciprofloxacin by microdilution. Moreover, 146 strains (2011-2013) were tested against ciprofloxacin by E-test. Reduced ciprofloxacin susceptibility was defined as a MIC of 0.125-1 mg/L.
Of 42 isolates with reduced ciprofloxacin susceptibility, four isolates showing nonclassical quinolone resistance phenotype. Three were confirmed as carrying of plasmid-mediated quinolone resistance-conferring genes qnr.
The percentage of strains with a genotype that confers a nonclassical quinolone resistance phenotype is low in our series. The identification of these isolates is difficult using conventional methods, but its ability of horizontal spread recommends an appropriate identification. Taking into account the low isolation rate of these strains in this study, evaluation of ciprofloxacin MIC on every nalidixic acid susceptible strain would not be cost effective. Alternatively, we propose to evaluate periodically any changing trend.
沙门氏菌属对氟喹诺酮类药物的敏感性降低可能导致治疗失败。环丙沙星用于儿童肠外和严重肠道沙门氏菌感染存在争议，因此这些菌株的临床相关性不大。因此，我们对儿科人群中沙门氏菌菌株的喹诺酮耐药性了解甚少。本研究的目的是评估儿科患者中非经典喹诺酮耐药表型的发生率。
对马德里尼尼奥·耶稣大学儿童医院（2009 - 2013年）的268株沙门氏菌进行了萘啶酸和环丙沙星的微量稀释试验。此外，对146株菌株（2011 - 2013年）进行了环丙沙星的E试验。环丙沙星敏感性降低定义为最低抑菌浓度（MIC）为0.125 - 1mg/L。
在42株环丙沙星敏感性降低的分离株中，有4株表现出非经典喹诺酮耐药表型。其中3株被确认为携带质粒介导的喹诺酮耐药基因qnr。
在我们的研究系列中，具有赋予非经典喹诺酮耐药表型基因型的菌株百分比很低。使用传统方法很难鉴定这些分离株，但其水平传播能力建议进行适当鉴定。考虑到本研究中这些菌株的分离率较低，对每一株对萘啶酸敏感的菌株进行环丙沙星MIC评估不具有成本效益。另外，我们建议定期评估任何变化趋势。
