Detection of decreased fluoroquinolone susceptibility in salmonellas and validation of nalidixic acid screening test
Detection of decreased fluoroquinolone susceptibility in salmonellas and validation of nalidixic acid screening test
复制标题
DOI：
10.1128/jcm.37.11.3572-3577.1999
复制
发表时间：
1999-11-01
影响因子：
9.4
通讯作者：
Huovinen, P
中科院分区：
文献类型：
--
作者：
Hakanen, A;Kotilainen, P;Huovinen, P
根据国家临床实验室标准委员会对萘啶酸和三种氟喹诺酮类药物的敏感性指南，我们评估了1010株被分类为氟喹诺酮类药物敏感的沙门氏菌，这些分离株被分为两个不同的亚群，绝大多数（n = 960）对环丙沙星完全敏感，少数（n = 50）对环丙沙星敏感性降低（mic范围在0.125和0.5 μ g/ml之间）。环丙沙星不太敏感的菌株对萘啶酸均耐药，而完全敏感的菌株中只有12株（1.3%）耐药。对钠地酸的抗性与对氧氟沙星或诺氟沙星的敏感性降低之间也存在类似的关联。在环丙沙星mic大于或等于0.125 μ g/ml的所有分离株中都可以发现gyrA基因突变，并且在94%的耐钠地酸分离株中可以发现gyrA基因突变，但在所分析的钠地酸敏感分离株中没有发现gyrA基因突变。对环丙沙星mic≥0.125 μ g/ml的分离株，采用纸片扩散法进行耐钠地酸鉴定，灵敏度为100%，特异性为87.3%。我们认为重要的是，微生物实验室努力识别这些不太敏感的沙门氏菌菌株，以揭示其临床重要性和调查其流行传播。
We evaluated 1,010 Salmonella isolates classified as fluoroquinolone susceptible according to the National Committee for Clinical Laboratory Standards guidelines for susceptibility to nalidixic acid and three fluoroquinolones, These isolates were divided into two distinct subpopulations, with the great majority (n = 960) being fully ciprofloxacin susceptible and a minority (n = 50) exhibiting reduced ciprofloxacin susceptibility (MICs ranging between 0.125 and 0.5 mu g/ml). The less ciprofloxacin-susceptible isolates were uniformly resistant to nalidixic acid, while only 12 (1.3%) of the fully susceptible isolates were nalidixic acid resistant. A similar association was observed between resistance to nalidixic acid and decreased susceptibility to ofloxacin or norfloxacin. A mutation of the gyrA gene could be demonstrated in all isolates for which the ciprofloxacin MICs were greater than or equal to 0.125 mu g/ml and in 94% of the nalidixic acid-resistant isolates but in none of the nalidixic acid-susceptible isolates analyzed. Identification of nalidixic acid resistance by the disk diffusion method provided a sensitivity of 100% and a specificity of 87.3% as tools to screen for isolates for which the MICs of ciprofloxacin were greater than or equal to 0.125 mu g/ml. We regard it as important that microbiology laboratories endeavor to recognize these less susceptible Salmonella strains, in order to reveal their clinical importance and to survey their epidemic spread.