Acanthamoeba containing endosymbiotic chlamydia isolated from hospital environments and its potential role in inflammatory exacerbation

BMC Microbiology

Research Article

Torahiko Okubo¹  Junji Matsuo¹  Hiroyuki Yamaguchi¹  Shinji Nakamura²  Hitoshi Shibuya³  Chikara Shimizu³  Kouji Akizawa³  Tatsuya Fukumoto³  Kentaro Miyamoto⁴  Motomichi Takahashi⁴  Kentaro Oka⁴ 

[1] Department of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University Graduate School of Health Sciences, Nishi-5 Kita-12 Jo, Kita-ku, 060-0812, Sapporo, Hokkaido, Japan;Division of Biomedical Imaging Research, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, 113-8421, Tokyo, Japan;Hokkaido University Hospital, Nishi-5 Kita-14 Jo, Kita-ku, 060-8648, Sapporo, Hokkaido, Japan;Miyarisan Pharmaceutical Co., Ltd., 2-3-13-209, Minami, 351-0104, Wako-shi, Saitama, Japan;

关键词: Acanthamoeba;    Environmental chlamydiae;    Hospital;    IL-8;    Genome sequence;   

DOI  :  10.1186/s12866-016-0906-1

 received in 2016-05-22, accepted in 2016-11-29,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundEnvironmental chlamydiae belonging to the Parachlamydiaceae are obligate intracellular bacteria that infect Acanthamoeba, a free-living amoeba, and are a risk for hospital-acquired pneumonia. However, whether amoebae harboring environmental chlamydiae actually survive in hospital environments is unknown. We therefore isolated living amoebae with symbiotic chlamydiae from hospital environments.ResultsOne hundred smear samples were collected from Hokkaido University Hospital, Sapporo, Japan; 50 in winter (February to March, 2012) and 50 in summer (August, 2012), and used for the study. Acanthamoebae were isolated from the smear samples, and endosymbiotic chlamydial traits were assessed by infectivity, cytokine induction, and draft genomic analysis. From these, 23 amoebae were enriched on agar plates spread with heat-killed Escherichia coli. Amoeba prevalence was greater in the summer-collected samples (15/30, 50%) than those of the winter season (8/30, 26.7%), possibly indicating a seasonal variation (p = 0.096). Morphological assessment of cysts revealed 21 amoebae (21/23, 91%) to be Acanthamoeba, and cultures in PYG medium were established for 11 of these amoebae. Three amoebae contained environmental chlamydiae; however, only one amoeba (Acanthamoeba T4) with an environmental chlamydia (Protochlamydia W-9) was shown the infectious ability to Acanthamoeba C3 (reference amoebae). While Protochlamydia W-9 could infect C3 amoeba, it failed to replicate in immortal human epithelial, although exposure of HEp-2 cells to living bacteria induced the proinflammatory cytokine, IL-8. Comparative genome analysis with KEGG revealed similar genomic features compared with other Protochlamydia genomes (UWE25 and R18), except for a lack of genes encoding the type IV secretion system. Interestingly, resistance genes associated with several antibiotics and toxic compounds were identified.ConclusionThese findings are the first demonstration of the distribution in a hospital of a living Acanthamoeba carrying an endosymbiotic chlamydial pathogen.

【 授权许可】

CC BY   
© The Author(s). 2016