High-level fluoroquinolone resistance in ophthalmic clinical isolates belonging to the species Corynebacterium macginleyi
High-level fluoroquinolone resistance in ophthalmic clinical isolates belonging to the species Corynebacterium macginleyi
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DOI：
10.1128/jcm.01741-07
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发表时间：
2008-02-01
影响因子：
9.4
通讯作者：
Shiota, Hiroshi
中科院分区：
文献类型：
--
作者：
Eguchi, Hiroshi;Kuwahara, Tomomi;Shiota, Hiroshi
非白喉棒状杆菌是正常人类皮肤和粘膜微生物群中普遍存在的成员，其对于眼表感染的临床重要性最近已得到认识。我们使用 Etest 试纸对三种氟喹诺酮类药物（环丙沙星、诺氟沙星和左氧氟沙星）进行了抗菌敏感性测试，并对眼科样本中的 21 株棒状杆菌分离株进行了分类学分析。根据 16S rRNA 基因序列比较，其中 16 个分离株在物种水平上被鉴定为 C. macginleyi。其余 5 个分离株被确定为 C. mastitidis（4 个）或 C. accolens（1 个）。 11 个 C. macginleyi 分离株对所有测试的氟喹诺酮类药物均表现出高水平的耐药性，其中 1 个分离株仅对诺氟沙星具有耐药性。对gyrA基因扩增的喹诺酮耐药决定区的分析表明，gyrA产物第83位的单个氨基酸取代足以产生诺氟沙星耐药表型，而导致第83位和第87位氨基酸变化的双突变对于对其他氟喹诺酮类药物的高水平耐药是必要的。我们对 C. macginleyi 进行了第一个多位点序列分型 (MLST) 分析。 MLST 分析将大多数 C. macginleyi 分离株分组为单一谱系，而通过随机扩增的多态性 DNA 片段模式进行的另一种分子菌株分型支持了这一发现，表明 C. macginleyi 的特定谱系在人类眼表面占主导地位。这类人群可能特别适应人类眼表的环境。
The clinical importance of nondiphtherial Corynebacterium, a ubiquitous member of the normal human microflorra of the skin and mucous membrane, for ocular surface infections has been recognized recently. We performed an antimicrobial susceptibility test with Etest strips for three fluoroquinolones (ciproffoxacin, norfloxacin, and levofloxacin) and a taxonomic analysis on 21 isolates of Corynebacterium from ophthalmic samples. Of these, 16 isolates were identified as C. macginleyi at the species level on the basis of 16S rRNA gene sequence comparisons. The remaining five isolates were determined to be C. mastitidis (four) or C. accolens (one). Eleven of the C. macginleyi isolates showed high levels of resistance to all of the fluoroquinolones tested, and one isolate was resistant to norfloxacin alone. An analysis of the amplified quinolone-resistance-determining regions of the gyrA genes revealed that a single amino acid substitution in position 83 of the gyrA product was sufficient to generate the norfloxacin resistance phenotype, and double mutations leading to amino acid changes in positions 83 and 87 were necessary for high-level resistance against the other fluoroquinolones. We conducted the first example of multilocus sequence typing (MLST) analysis on C. macginleyi. The MLST analysis grouped the majority of C. macginleyi isolates into a single lineage, and another molecular strain typing by random amplified polymorphic DNA fragment patterns supported the finding, indicating that a particular lineage of C. macginleyi is dominant on the human ocular surface. This type of population might be particularly adaptable to the milieu on the human ocular surface.