Phenotypic characterization of clonal and nonclonal Pseudomonas aeruginosa strains isolated from lungs of adults with cystic fibrosis
Phenotypic characterization of clonal and nonclonal Pseudomonas aeruginosa strains isolated from lungs of adults with cystic fibrosis
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DOI：
10.1128/jcm.02364-06
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发表时间：
2007-06-01
影响因子：
9.4
通讯作者：
Harbour, Colin
中科院分区：
文献类型：
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作者：
Tingpej, Pholawat;Smith, Lucas;Harbour, Colin
剧毒铜绿假单胞菌克隆的出现对全球囊性纤维化 (CF) 患者构成威胁。克隆铜绿假单胞菌菌株的表征对于了解其临床影响和制定解决该问题的策略至关重要。两种克隆菌株（AES-1 和 AES-2）在澳大利亚东部的 CF 中心内传播。在本研究中，比较了 43 种（14 种 AES-1、5 种 AES-2 和 24 种非克隆）铜绿假单胞菌分离株的表型特征，以深入了解克隆菌株的特性。所有 43 个分离株在 vfr、rhII、rhlR、lasA、lasB、aprA、rhlAB 和 exoS 基因的 PCR 中均产生了预测大小的条带； 42 例 lasI 和 lasR 呈阳性，无一例具有 exoU。三十七 (86%) 分离株在总蛋白酶检测中呈阳性；根据酶谱分析，24 个（56%）产生弹性蛋白酶/葡萄球菌溶血素，22 个（51%）产生碱性蛋白酶。克隆分离株比非克隆分离株更有可能呈总蛋白酶阳性（P = 0.02），通过酶谱法显示弹性蛋白酶和碱性蛋白酶活性（分别为 P = 0.04 和 P = 0.01），并通过弹性蛋白-刚果红测定显示弹性蛋白酶活性（P = 0.04）。与基因型没有其他关联。总体而言，患者年龄的增加与弹性蛋白酶活性的降低相关（P = 0.03）。通过薄层色谱分析，三十二个 (74%) 分离株至少含有一种 N-酰基高丝氨酸内酯 (AHL)。 rhl 相关的 AHL 检测与总蛋白酶和弹性蛋白酶活性的产生和水平相关（所有 P < 0.01）。通过蛋白质印迹分析，33 个 (77%) 分离株呈 ExoS 阳性，35 个 (81%) 分离株产生鼠李糖脂，34 个 (79%) 个分离株显示几丁质酶活性。研究结果表明，慢性感染期间的蛋白酶活性可能有助于这些克隆菌株的传播性或毒力。
The emergence of virulent Pseudomonas aeruginosa clones is a threat to cystic fibrosis (CF) patients globally. Characterization of clonal P. aeruginosa strains is critical for an understanding of its clinical impact and developing strategies to meet this problem. Two clonal strains (AES-1 and AES-2) are circulating within CF centers in eastern Australia. In this study, phenotypic characteristics of 43 (14 AES-1, 5 AES-2, and 24 nonclonal) P. aeruginosa isolates were compared to gain insight into the properties of clonal strains. All 43 isolates produced bands of the predicted size in PCRs for vfr, rhII, rhlR, lasA, lasB, aprA, rhlAB, and exoS genes; 42 were positive for lasI and lasR, and none had exoU. Thirty-seven (86%) isolates were positive in total protease assays; on zymography, 24 (56%) produced elastase/staphylolysin and 22 (51%) produced alkaline protease. Clonal isolates were more likely than nonclonal isolates to be positive for total proteases (P = 0.02), to show elastase and alkaline protease activity by zymography (P = 0.04 and P = 0.01, respectively), and to show elastase activity by the elastin-Congo red assay (P = 0.04). There were no other associations with genotype. Overall, increasing patient age was associated with decreasing elastase activity (P = 0.03). Thirty-two (74%) isolates had at least one N-acylhomoserine lactone (AHL) by thin-layer chromatography. rhl-associated AHL detection was associated with the production and level of total protease and elastase activity (all P < 0.01). Thirty-three (77%) isolates were positive for ExoS by Western blot analysis, 35 (81%) produced rhamnolipids, and 34 (79%) showed chitinase activity. Findings suggest that protease activity during chronic infection may contribute to the transmissibility or virulence of these clonal strains.