Xie Jingping, Juliao Patricia C, Gilsdorf Janet R, Ghosh Debashis, Patel Mayuri, Marrs Carl F
Department of Epidemiology, University of Michigan School of Public Health, 109 Observatory Street, Ann Arbor, MI 48109-2029, USA.
J Clin Microbiol. 2006 Dec;44(12):4316-25. doi: 10.1128/JCM.01331-06. Epub 2006 Sep 27.
Nontypeable (NT) Haemophilus influenzae strains cause significant respiratory illness and are isolated from up to half of middle ear aspirates from children with acute otitis media. Previous studies have identified two genes, lic2B and hmwA, that are associated with NT H. influenzae strains isolated from the middle ears of children with otitis media but that are not associated with NT H. influenzae strains isolated from the throats of healthy children, suggesting that they may play a role in virulence in otitis media. In this study, genomic subtraction was used to identify additional genetic regions unique to middle ear strains. The genome of NT H. influenzae middle ear strain G622 was subtracted from that of NT H. influenzae throat strain 23221, and the resultant gene regions unique to the middle ear strain were identified. Subsequently, the relative prevalence of the middle ear-specific gene regions among a large panel of otitis media and throat strains was determined by dot blot hybridization. By this approach, nine genetic regions were found to be significantly more prevalent in otitis media strains. Classification tree analysis of lic2B, hmwA, and the nine new potential otitis media virulence genes revealed two H. influenzae pathotypes associated with otitis media.
不可分型（NT）流感嗜血杆菌菌株可引发严重的呼吸道疾病，在急性中耳炎患儿的中耳吸出物中，高达半数可分离出该菌株。此前的研究已鉴定出两个基因，即lic2B和hmwA，它们与从患有中耳炎的儿童中耳分离出的NT流感嗜血杆菌菌株相关，但与从健康儿童咽喉分离出的NT流感嗜血杆菌菌株无关，这表明它们可能在中耳炎的致病性中发挥作用。在本研究中，采用基因组消减技术来鉴定中耳菌株特有的其他基因区域。从NT流感嗜血杆菌咽喉菌株23221的基因组中消减NT流感嗜血杆菌中耳菌株G622的基因组，从而鉴定出中耳菌株特有的基因区域。随后，通过斑点杂交法测定中耳特异性基因区域在大量中耳炎菌株和咽喉菌株中的相对流行率。通过这种方法，发现9个基因区域在中耳炎菌株中显著更常见。对lic2B、hmwA和9个新的潜在中耳炎毒力基因进行分类树分析，揭示了与中耳炎相关的两种流感嗜血杆菌致病型。
