Queensland Paediatric Infectious Diseases Laboratory, Queensland Children's Medical Research Institute, Royal Children's Hospital, The University of Queensland, Brisbane, Queensland, Australia.
PLoS One. 2012;7(9):e44199. doi: 10.1371/journal.pone.0044199. Epub 2012 Sep 6.
Pseudomonas aeruginosa is an opportunistic pathogen and an important cause of infection, particularly amongst cystic fibrosis (CF) patients. While specific strains capable of patient-to-patient transmission are known, many infections appear to be caused by unique and unrelated strains. There is a need to understand the relationship between strains capable of colonising the CF lung and the broader set of P. aeruginosa isolates found in natural environments. Here we report the results of a multilocus sequence typing (MLST)-based study designed to understand the genetic diversity and population structure of an extensive regional sample of P. aeruginosa isolates from South East Queensland, Australia. The analysis is based on 501 P. aeruginosa isolates obtained from environmental, animal and human (CF and non-CF) sources with particular emphasis on isolates from the Lower Brisbane River and isolates from CF patients obtained from the same geographical region. Overall, MLST identified 274 different sequence types, of which 53 were shared between one or more ecological settings. Our analysis revealed a limited association between genotype and environment and evidence of frequent recombination. We also found that genetic diversity of P. aeruginosa in Queensland, Australia was indistinguishable from that of the global P. aeruginosa population. Several CF strains were encountered frequently in multiple ecological settings; however, the most frequently encountered CF strains were confined to CF patients. Overall, our data confirm a non-clonal epidemic structure and indicate that most CF strains are a random sample of the broader P. aeruginosa population. The increased abundance of some CF strains in different geographical regions is a likely product of chance colonisation events followed by adaptation to the CF lung and horizontal transmission among patients.
铜绿假单胞菌是一种机会性病原体，也是感染的重要原因，尤其是在囊性纤维化（CF）患者中。虽然已知有一些特定的菌株能够在患者之间传播，但许多感染似乎是由独特且不相关的菌株引起的。我们需要了解能够定植 CF 肺部的菌株与在自然环境中发现的更广泛的铜绿假单胞菌分离株之间的关系。在这里，我们报告了一项基于多位点序列分型（MLST）的研究结果，该研究旨在了解澳大利亚东南部昆士兰州广泛区域的铜绿假单胞菌分离株的遗传多样性和种群结构。该分析基于从环境、动物和人类（CF 和非 CF）来源获得的 501 株铜绿假单胞菌分离株，特别强调了来自下布里斯班河的分离株和来自同一地理区域的 CF 患者的分离株。总体而言，MLST 确定了 274 个不同的序列类型，其中 53 个序列类型在一个或多个生态环境中共享。我们的分析表明基因型和环境之间的关联有限，并且存在频繁重组的证据。我们还发现，澳大利亚昆士兰州的铜绿假单胞菌遗传多样性与全球铜绿假单胞菌群体的遗传多样性无法区分。一些 CF 菌株在多个生态环境中频繁出现；然而，最常遇到的 CF 菌株仅限于 CF 患者。总体而言，我们的数据证实了非克隆的流行结构，并表明大多数 CF 菌株是更广泛的铜绿假单胞菌群体的随机样本。一些 CF 菌株在不同地理区域的丰度增加很可能是偶然定植事件的产物，随后是对 CF 肺部的适应以及患者之间的水平传播。
