小児気道由来 nontypable Haemophilus influenzae の付着因子と biofilm 形成能 [in Japanese] Prevalence of adhesin genes and biofilm formation among clinical isolates of nontypable Haemophilus influenzae [in Japanese]
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本邦の小児気道由来nontypable <I>Haemophilus influenzae</I> (NTHi) の付着因子とbiofilm形成能についての報告はない。NTHi108株について, 線毛遺伝子<I>hif A</I>, 付着遺伝子<I>hmw, hia, hap</I>, biofilm関連遺伝子sia BをPCRで検出し, biofilm形成能をmicrotiter plate法で測定した。保有頻度は, <I>hif A</I>22.2%, <I>hmw</I>48.1%, <I>hia</I>55.6%, <I>hap</I>22.2%, <I>sia B</I>38.0%。保有状況とbiofilm形成能には多様性がみられた。<I>hifA</I>と<I>hia</I>陽性株にはbiofilm形成株が多く (P=0.0245, 0.0360), hif Aとhiaはbiofilm形成能と関連していた。反復性下気道感染症患者9名19株には, 急性患者に比べてbiofilm形成株が多く (89.5%vs.63.2%), 下気道感染症の遷延にbiofilmの関与が示唆された。
The pathogenesis of repiratory infections due to nontypable <I>Haemophilus influenzae</I> (NTHi) begins with bacterial colonization of mucosa. Adhesins such as hemagglutinating pili (Hif A), HMW1/2, Hia, Hap are important in this process.Recently, biofilm formation of NTHi was reported to play a role in the pathogenesis of otitis media and the respiratory infections.However, there are few reports on the prevalence of adhesins and the biofilm formation among clinical isolates of NTHi. We examined 108 strains of NTHi for adhesin genes and a biofilm-related gene by PCR, and for biofilm formation by a quantitative biofilm assay.The prevalence of adhesin genes were as follows: <I>hif A</I> 22.2%, <I>hmw</I> 48.1%, <I>hia</I> 55.6%, <I>hap</I> 22.2%, <I>sia B</I> 38.0%.Variability among isolates was observed in their ability to form biofilms.The rate of a biofilm-positive strain was significantly higher in hif A or hia positive strains than negative strains (p =0.0245 and 0.0360, respectively).Furthermore, the incidence of a biofilm-positive strain was higher among strains from patients with recurrent respiratory infections than those from patients with acute infections (89.5% vs.63.2%).We conclude that hemagglutinating pili and Hia are associated with bioflm formation, and that biofilm formation plays an important role in recurrent respiratory infections.
JJPP 17(2), 143-150, 2006-12-28
Japanese Society of Pediatric Pulmonology