Murphy Timothy F, Brauer Aimee L, Sethi Sanjay, Kilian Mogens, Cai Xueya, Lesse Alan J
Department of Medicine, University at Buffalo, State University of New York, Buffalo, NY, USA.
J Infect Dis. 2007 Jan 1;195(1):81-9. doi: 10.1086/509824. Epub 2006 Nov 27.
Haemophilus influenzae is a common pathogen in adults with chronic obstructive pulmonary disease (COPD). In a prospective study, selected isolates of apparent H. influenzae had an altered phenotype. We tested the hypothesis that these variant strains were genetically different from typical H. influenzae.
A prospective study of adults with COPD was conducted. Strains of apparent H. influenzae obtained from a range of clinical sources were evaluated by ribosomal DNA sequence analysis, multilocus sequence analysis, DNA-DNA hybridization, and sequencing of the conserved P6 gene.
Variant strains were determined to be Haemophilus haemolyticus by means of 4 independent methods. Analysis of 490 apparent H. influenzae strains, identified by standard methods, revealed that 39.5% of sputum isolates and 27.3% of nasopharyngeal isolates were H. haemolyticus. Isolates obtained from normally sterile sites were all H. influenzae. In a prospective study, acquisitions of new strains of H. haemolyticus were not associated with exacerbations of COPD, whereas 45% of acquisitions of new strains of H. influenzae were associated with exacerbations.
Standard methods do not reliably distinguish H. haemolyticus from H. influenzae. H. haemolyticus is a respiratory tract commensal. The recognition that some strains of apparent H. influenzae are H. haemolyticus substantially strengthens the association of true H. influenzae with clinical infection.
流感嗜血杆菌是慢性阻塞性肺疾病（COPD）成年患者中的常见病原体。在一项前瞻性研究中，部分表面上的流感嗜血杆菌分离株出现了表型改变。我们检验了这样一个假设，即这些变异菌株在基因上与典型的流感嗜血杆菌不同。
对COPD成年患者进行了一项前瞻性研究。通过核糖体DNA序列分析、多位点序列分析、DNA-DNA杂交以及保守的P6基因测序，对从一系列临床来源获得的表面上的流感嗜血杆菌菌株进行了评估。
通过4种独立方法确定变异菌株为溶血嗜血杆菌。对用标准方法鉴定的490株表面上的流感嗜血杆菌菌株进行分析发现，痰液分离株中有39.5%以及鼻咽分离株中有27.3%为溶血嗜血杆菌。从通常无菌部位获得的分离株均为流感嗜血杆菌。在一项前瞻性研究中，获得新的溶血嗜血杆菌菌株与COPD加重无关，而获得新的流感嗜血杆菌菌株中有45%与加重有关。
标准方法不能可靠地区分溶血嗜血杆菌和流感嗜血杆菌。溶血嗜血杆菌是呼吸道共生菌。认识到部分表面上的流感嗜血杆菌菌株实际上是溶血嗜血杆菌，大大加强了真正的流感嗜血杆菌与临床感染之间的关联。
