Role of the Nuclease of Nontypeable Haemophilus influenzae in Dispersal of Organisms from Biofilms
Role of the Nuclease of Nontypeable Haemophilus influenzae in Dispersal of Organisms from Biofilms
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DOI：
10.1128/iai.02601-14
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发表时间：
2015-03-01
影响因子：
3.1
通讯作者：
Apicella, Michael A.
中科院分区：
文献类型：
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作者：
Cho, Christine;Chande, Aroon;Apicella, Michael A.
不可分型流感嗜血杆菌 (NTHI) 在人类感染期间在中耳形成生物膜。 NTHI 的生物膜基质含有细胞外 DNA。我们证明 NTHI 具有有效的核酸酶，它是金黄色葡萄球菌热核酸酶的同源物。使用生物膜分散测定，研究显示亲本菌株中存在生物膜分散模式，核酸酶突变体中没有分散的证据，而互补突变体中分散部分恢复。对 24 小时连续流动系统的生物膜 mRNA 进行定量 PCR 表明，与生物膜生长阶段相比，浮游生物的核酸酶表达显着增加 (P < 0.042)。对体外生长的生物膜的显微镜分析表明，与野生型和互补菌株相比，核酸酶突变体的核酸基质有所增加。生物体通常以大聚集体的形式存在，与野生型和补体生物膜不同，野生型和补体生物膜中生物体均匀地分散在整个生物膜中。48小时，突变型生物膜中的大多数生物体死亡。核酸酶突变体在龙猫中耳炎模型中形成生物膜，并表现出也形成类似的大型生物体聚集体的倾向。这些研究表明 NTHI 核酸酶参与生物膜重塑和生物体分散。
Nontypeable Haemophilus influenzae (NTHI) forms biofilms in the middle ear during human infection. The biofilm matrix of NTHI contains extracellular DNA. We show that NTHI possesses a potent nuclease, which is a homolog of the thermonuclease of Staphylococcus aureus. Using a biofilm dispersal assay, studies showed a biofilm dispersal pattern in the parent strain, no evidence of dispersal in the nuclease mutant, and a partial return of dispersion in the complemented mutant. Quantitative PCR of mRNA from biofilms from a 24-h continuous flow system demonstrated a significantly increased expression of the nuclease from planktonic organisms compared to those in the biofilm phase of growth (P < 0.042). Microscopic analysis of biofilms grown in vitro showed that in the nuclease mutant the nucleic acid matrix was increased compared to the wild-type and complemented strains. Organisms were typically found in large aggregates, unlike the wild-type and complement biofilms in which the organisms were evenly dispersed throughout the biofilm At 48 h, the majority of the organisms in the mutant biofilm were dead. The nuclease mutant formed a biofilm in the chinchilla model of otitis media and demonstrated a propensity to also form similar large aggregates of organisms. These studies indicate that NTHI nuclease is involved in biofilm remodeling and organism dispersal.