Diverse mutations in the ftsI gene in ampicillin-resistant Haemophilus influenzae isolates from pediatric patients with acute otitis media
Diverse mutations in the ftsI gene in ampicillin-resistant Haemophilus influenzae isolates from pediatric patients with acute otitis media
复制标题
DOI：
10.1007/s10156-009-0011-6
复制
发表时间：
2010-04-01
影响因子：
2.2
通讯作者：
Ubukata, Kimiko
中科院分区：
文献类型：
--
作者：
Kishii, Kozue;Chiba, Naoko;Ubukata, Kimiko
为了阐明日本儿童急性中耳炎(AOM)患者中不产生β-内酰胺酶的耐氨苄西林流感嗜血杆菌(BLNAR)的分子变化，我们确定了BLNAR菌株的青霉素结合蛋白3中的氨基酸(AA)替换。2005年10月至2008年3月，从AOM患儿中耳液中分离出191株流感嗜血杆菌，其中BLNAR占49.2%。在BLNAR菌株中，91.5%有4个氨基酸替换：Met377Ile、Ser385Thr、Leu389Phe以及Asn526Lys或Arg517His。此外，还注意到在Ser327-Thr-Val-Lys的保守AA基序中具有Val329Ala的新的AA替换，或与Lys512-Thr-Gly的保守AA基序相邻的Val511Ala的BLNAR菌株的出现。将FTSI基因转化到RD参考菌株(ATCC 51907)中，表明这两个AA替换比头孢菌素更能降低阿莫西林的敏感性。BLNAR菌株的脉冲场凝胶电泳谱高度多样化。这些结果表明，不适当的抗生素使用可能通过选择FTSI基因的突变来增加BLNAR菌株，这种使用可能有利于新的AA替换。
To clarify molecular changes in beta-lactamase-nonproducing, ampicillin-resistant (BLNAR) Haemophilus influenzae, which is increasing in pediatric patients with acute otitis media (AOM) in Japan, we identified amino acid (aa) substitutions in penicillin-binding protein 3 for the BLNAR strains. Of 191 H. influenzae strains isolated from middle ear fluid of pediatric AOM patients between October 2005 and March 2008, BLNAR strains determined by PCR accounted for 49.2%. Of the BLNAR strains, 91.5% possessed 4 aa substitutions: Met377Ile, Ser385Thr, Leu389Phe, and either Asn526Lys or Arg517His. Additionally, the emergence of BLNAR strains possessing a new aa substitution of Val329Ala in the conserved aa motif of Ser327-Thr-Val-Lys, or Val511Ala adjacent to the conserved aa motif of Lys512-Thr-Gly, was noted. Transformation of the ftsI gene into the Rd reference strain (ATCC 51907) demonstrated that these two aa substitutions reduced susceptibility to amoxicillin more than to cephalosporins. Pulsed-field gel electrophoretic profiles of BLNAR strains were highly diverse. These results suggested that inadequate antibiotic use may increase BLNAR strains by selecting mutations in the ftsI gene and that such use may have favored the new aa substitutions.