title: Development of a method for detecting Coxiella burnetii in cheese samples.
abstract: Coxiella burnetii is the causative agent of Q fever, and the main route of infection in humans is inhalation of contaminated aerosols. Although oral transmission by contaminated raw milk or dairy products is also a possible route of human infection, there have been few studies investigating the presence of C. burnetii in dairy products. We developed a new method of extracting DNA from cheese and detecting C. burnetii DNA in cheese samples with a nested PCR assay. The limit of detection was 6.0 × 10(2) C. burnetii particles per gram. We subsequently used this method to examine the presence of C. burnetii in cheese at commercial markets in Tokyo from June 2005 to December 2008. Twenty-eight of 147 cheese samples were found to be positive for C. burnetii DNA. However, when we assessed the viability of C. burnetii by inoculating mice with DNA-positive samples, all of the samples were found to be negative. Thus, the viability of C. burnetii appears to have been lost in these cheese samples.
authors: Department of Microbiology, Tokyo Metropolitan Institute of Public Health, 3–24–1 Hyakunin-cho, Shinjuku-ku, Tokyo 169–0073, Japan. Akihiko_Hirai@member.metro.tokyo.jp
authors: Akihiko
authors: A
authors: Hirai
authors: Akiko
authors: A
authors: Nakama
authors: Takashi
authors: T
authors: Chiba
authors: Akemi
authors: A
authors: Kai
mesh_terms: D000818:Animals; D001681:Biological Assay; D002611:Cheese / Q000382:microbiology*; D016997:Coxiella burnetii / Q000235:genetics / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005516:Food Microbiology; D051379:Mice; D016133:Polymerase Chain Reaction / Q000379:methods*; D011778:Q Fever / Q000382:microbiology / Q000517:prevention & control
chemical_list: D004269:DNA, Bacterial