Branley James, Bachmann Nathan L, Jelocnik Martina, Myers Garry S A, Polkinghorne Adam
Department of Microbiology and Infectious Diseases, Nepean Hospital Penrith NSW, Australia.
Centre for Animal Health Innovation, University of the Sunshine Coast, Sippy Downs, Australia.
Sci Rep. 2016 Aug 4;6:30019. doi: 10.1038/srep30019.
Chlamydia psittaci is an avian pathogen and zoonotic agent of atypical pneumonia. The most pathogenic C. psittaci strains cluster into the 6BC clade, predicted to have recently emerged globally. Exposure to infected parrots is a risk factor with limited evidence also of an indirect exposure risk. Genome sequencing was performed on six Australian human and a single avian C. psittaci strain isolated over a 9 year period. Only one of the five human patients had explicit psittacine contact. Genomics analyses revealed that the Australian C. psittaci strains are remarkably similar, clustering tightly within the C. psittaci 6BC clade suggested to have been disseminated by South America parrot importation. Molecular clock analysis using the newly sequenced C. psittaci genomes predicted the emergence of the 6BC clade occurring approximately 2,000 years ago. These findings reveal the potential for an Australian natural reservoir of C. psittaci 6BC strains. These strains can also be isolated from seriously ill patients without explicit psittacine contact. The apparent recent and global spread of C. psittaci 6BC strains raises important questions over how this happened. Further studies may reveal whether the dissemination of this important zoonotic pathogen is linked to Australian parrot importation rather than parrots from elsewhere.
鹦鹉热衣原体是一种禽类病原体以及非典型肺炎的人畜共患病原体。致病性最强的鹦鹉热衣原体菌株聚集在6BC进化枝中，预计是最近在全球出现的。接触受感染的鹦鹉是一个风险因素，也有有限的证据表明存在间接接触风险。对在9年期间分离出的6株澳大利亚人类和1株禽类鹦鹉热衣原体菌株进行了基因组测序。5名人类患者中只有1人有明确的鹦鹉接触史。基因组学分析表明，澳大利亚的鹦鹉热衣原体菌株非常相似，紧密聚集在鹦鹉热衣原体6BC进化枝内，推测是由南美洲鹦鹉进口传播的。使用新测序的鹦鹉热衣原体基因组进行分子钟分析预测，6BC进化枝大约在2000年前出现。这些发现揭示了澳大利亚存在鹦鹉热衣原体6BC菌株天然宿主的可能性。这些菌株也可以从没有明确鹦鹉接触史的重症患者中分离出来。鹦鹉热衣原体6BC菌株最近在全球范围内的明显传播引发了关于其传播方式的重要问题。进一步的研究可能会揭示这种重要的人畜共患病原体的传播是否与澳大利亚鹦鹉进口有关，而不是与其他地方的鹦鹉有关。
