title: Impact of free-living amoebae on presence of Parachlamydia acanthamoebae in the hospital environment and its survival in vitro without requirement for amoebae.
abstract: Parachlamydia acanthamoebae is an obligately intracellular bacterium that infects free-living amoebae and is a potential human pathogen in hospital-acquired pneumonia. We examined whether the presence of P. acanthamoebae is related to the presence of Acanthamoeba in an actual hospital environment and assessed the in vitro survival of P. acanthamoebae. Ninety smear samples were collected between November 2007 and March 2008 (trial 1, n = 52) and between October 2008 and February 2009 (trial 2, n = 38) from the floor (dry conditions, n = 56) and sink outlets (moist conditions, n = 34) of a hospital. The prevalences of P. acanthamoebae DNA in the first and second trials were 64.3% and 76%, respectively. The prevalences of Acanthamoeba DNA in the first and second trials were 48% and 63.1%, respectively. A statistical correlation between the prevalence of P. acanthamoebae and that of Acanthamoeba was found (trial 1, P = 0.011; trial 2, P = 0.022), and that correlation increased when samples from just the dry area (floor smear samples, P = 0.002) were analyzed but decreased when samples from a moist area were analyzed (P = 0.273). The in vitro experiment showed that, without Acanthamoeba, P. acanthamoebae could not survive in dry conditions for 3 days at 30 degrees C or 15 days at 15 degrees C. Thus, both organisms were coincidentally found in an actual hospital environment, with the presence of Acanthamoeba having a significant effect on the long-term survival of P. acanthamoebae, suggesting that this potential human pathogen could spread through a hospital environment via Acanthamoeba.
authors.affiliation: Hokkaido University Hospital, Nishi-5 Kita-14 Jo, Kita-ku, Sapporo, Hokkaido 060-0812, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Fukumoto
authors.forename: Junji
authors.initials: J
authors.lastname: Matsuo
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hayashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Oguri
authors.forename: Shinji
authors.initials: S
authors.lastname: Nakamura
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Mizutani
authors.forename: Takashi
authors.initials: T
authors.lastname: Yao
authors.forename: Kouzi
authors.initials: K
authors.lastname: Akizawa
authors.forename: Haruki
authors.initials: H
authors.lastname: Suzuki
authors.forename: Chikara
authors.initials: C
authors.lastname: Shimizu
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Matsuno
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yamaguchi
mesh_terms: D000048:Acanthamoeba / Q000302:isolation & purification* / Q000382:microbiology*; D000818:Animals; D002695:Chlamydiales / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology*; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004783:Environmental Microbiology; D006761:Hospitals; D006801:Humans; D050296:Microbial Viability; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S