Cultivos

JOURNAL OF CLINICAL MICROBIOLOGY, Oct. 2010, p. 3563–3568 0095-1137/10/$12.00 doi:10.1128/JCM.02224-09 Copyright © 2010, American Society for Microbiology. All Rights Reserved.

Vol. 48, No. 10

Identification, Molecular Characterization, and Occurrence of Two Bovine Hemoplasma Species in Swiss Cattle and Development of Real-Time TaqMan Quantitative PCR Assays for Diagnosis of BovineHemoplasma Infections
Marina L. Meli,1* Barbara Willi,1 Ute M. Dreher,1 Valentino Cattori,1 Gabriela Knubben-Schweizer,2 Karl Nuss,2 Ueli Braun,2 Hans Lutz,1 and Regina Hofmann-Lehmann1
Clinical Laboratory, Vetsuisse Faculty, University of Zurich, CH-8057 Zurich, Switzerland,1 and Department of Farm Animals, Vetsuisse Faculty, University of Zurich, CH-8057 Zurich, Switzerland2
Received 13 November2009/Returned for modification 20 February 2010/Accepted 23 July 2010

Concomitantly with an outbreak of fatal anaplasmosis in a cattle herd in Switzerland in 2002, we detected two bovine hemoplasma species in diseased animals: Mycoplasma wenyonii (formerly Eperythrozoon wenyonii) and a second, novel bovine hemoplasma species later designated “Candidatus Mycoplasma haemobos” (synonym, “CandidatusMycoplasma haemobovis”). The second species was characterized by a shorter 16S rRNA gene. The aims of the present study were to provide a detailed molecular characterization of this species, to develop specific quantitative real-time PCR assays for the two bovine hemoplasma species, and to apply these assays in order to evaluate the prevalence and clinical significance of the hemoplasmas. Sequencing ofthe near-complete 16S rRNA gene of the second hemoplasma revealed that it was 94% identical to that of Mycoplasma haemofelis, an anemia-inducing feline hemoplasma species, but less than 85% identical to that of the bovine hemoplasma M. wenyonii. Using the newly developed assays, a total of 159 animals from the anaplasmosis outbreak were reexamined. In addition, we tested 57 clinically ill and 61healthy Swiss cattle, as well as 47 calves. Both hemoplasmas were highly prevalent in adult cattle but occurred rarely in calves. Animals from the herd with the fatal anemia outbreak were more frequently infected with M. wenyonii and exhibited higher M. wenyonii blood loads than animals with unrelated diseases and healthy animals. Coinfections may increase the pathogenicity and clinical significanceof bovine hemoplasmosis. In connection with an outbreak of anaplasmosis in a cattle herd in eastern Switzerland in 2002, more than 300 animals were culled. Most of these cattle exhibited pronounced anemia. The anemia was statistically associated with the detection of Anaplasma marginale, Babesia spp., Theileria spp., and Mycoplasma wenyonii in the blood of diseased animals (5). M. wenyonii, firstdescribed in 1934, was formerly known as Eperythrozoon wenyonii (1, 13). The species was recently reclassified within the group of hemotropic mycoplasmal species based on the 16S rRNA gene sequence (11–13). M. wenyonii is a cell wall-free bacterium that parasitizes bovine red blood cells (11). In our study of the above-mentioned outbreak, we reported two distinct hemotropic mycoplasma species: M.wenyonii and a second, unknown, agent (5). The 16S rRNA gene of the second agent was shorter than that in M. wenyonii and was 95% identical to the 16S rRNA gene found in Mycoplasma haemofelis, the causative agent of feline infectious anemia (24, 25). A similar bovine hemoplasma species has since been detected in China and Japan using molecular assays, and the name “Candidatus Mycoplasma haemobos”has been proposed (20). Other bovine hemoplasmas that were found to be distinct from M. wenyonii using other methods are described elsewhere (3, 30–32). Characterization included morphological and immunogenic differences, as well as different localization of the agents within the host (28, 29, 31, 32, 38). The clinical relevance of M. wenyonii is controversial (16, 18); in the United States,...