Study for biofilm formed by Haemophilus influenzae on human bronchial epithelial cells

为了评价非分型流感嗜血杆菌(NTHi)和b型流感嗜血杆菌(Hib)的生物被膜形成情况，我们进行了以下对比研究。在进行血清学分型和聚合酶链式反应鉴定β-内酰胺酶阴性氨苄西林敏感株NTHi、β-内酰胺酶阴性Amp耐药株NTHi、TEM1型产β内酰胺酶耐药株NTHi和Hib后，进行生物被膜检测和扫描电子显微镜观察。生物被膜形成试验和扫描电子显微镜观察表明，除少数产生物膜的菌株外，大多数Hib菌株的生物被膜形成均低于NTHi，其中包括BLNAR、BLNAS和BLPAR菌株的生物被膜形成情况相似。聚合酶链式反应鉴定b型衣壳基因和序列表明，5株产生物膜的Hib菌株失去了其b型衣壳。此外，我们还通过生物被膜生成实验比较了几种抗生素对BLNAR和BLNAS菌株的抗生物被膜效果。结果表明，青霉素和头孢菌素对BLNAR和BLNAS菌株无抗生物被膜作用，而大环内酯类和喹诺酮类对BLNAR和BLNAS菌株有抗生物被膜作用，且呈剂量依赖关系。我们的数据表明，大多数Hib菌株形成生物被膜的程度低于NTHi，而BLNAR、BLNAS和BLPAR NTHi之间的生物被膜形成是不同的，并且几乎相似，并且流感嗜血杆菌中b被膜表达的丧失可能导致生物被膜形成的增强。此外，我们的数据表明，大环内酯类和喹诺酮类药物可以抑制流感嗜血杆菌形成的生物被膜。

To evaluate the biofilm formation between Nontypeable Haemophilus influenzae (NTHi) and H. influenzae type b (Hib), we conducted the following comparative study. After serotyping and performing PCR to identify β-lactamase-negative ampicillin (AMP)-susceptible (BLNAS) NTHi, β-lactamase-negative AMP-resistant (BLNAR) NTHi, TEM-1 type β-lactamase-producing AMP-resistant (BLPAR) NTHi and Hib, we conducted biofilm production assays and scanning electron microscopy (SEM). The biofilm production assay and SEM showed that NTHi, including the BLNAR, BLNAS and BLPAR strains were similar in terms of forming biofilms, whereas in most of the Hib strains biofilm formation was decreased, compared to NTHi except for a few biofilm-producing strains. PCR to identify the type b cap gene and sequences indicated that 5 of the biofilm-producing Hib strains had lost their b capsule. Also, we compared anti-biofilm effect by several antibiotics between BLNAR and BLNAS strains using biofilm production assays. The assay indicates that penicillin and cephalosporin do not have anti-biofilm effect, but macrolide and quinolone have anti-biofilm effect against BLNAR and BLNAS strains dose-dependently. Our data indicate that most Hib strains form biofilms to a lesser extent than NTHi, whereas biofilm formation among BLNAR, BLNAS and BLPAR NTHi are variable and almost similar, and that the loss of b capsule expression in H. influenzae may result in enhanced biofilm formation. Also, our data demonstrate that macrolide and quinolone may inhibit biofilm formed by Haemophilus influenzae.