Publications

4372

Abstract This report describes a case of canine hemotropic mycoplasmasosis by Candidatus Mycoplasma haematoparvum in a dog. A five-year-old splenectomized dog was referred to the Veterinary Teaching Hospital of the University of Sassari with clinical symptoms and laboratory findings compatible with immune-mediated hemolytic anemia. Epicellular bacteria were detected in the erythrocytes by microscopic examination of blood smears. PCR and sequencing were positive for Candidatus Mycoplasma haematoparvum. Treatment with doxycycline, prednisolone and blood transfusion was administered. Several studies have described the molecular prevalence of M. hemocanis and Candidatus M. haematoparvum, however there are few clinical reports, especially those describing Candidatus M. haematoparvum infection in dogs, for which only two cases have been reported. To the best of our knowledge this is the first case report of a symptomatic infection caused by Candidatus Mycoplasma haematoparvum in Italy. Hemoplasmosis should be considered as a potential cause of hemolytic anemia in dogs. Following treatment with doxycycline and prednisolone, the clinical signs improved without resolution of infection. This condition was the same at the three-year follow-up.

Summary Oxidation of nitrite to nitrate is an important process in the global nitrogen cycle. Recent molecular biology‐based studies have revealed that the widespread nitrite‐oxidizing bacteria (NOB) belonging to the genus ‘ Candidatus Nitrotoga’ may be highly important for the environment. However, the insufficient availability of pure Nitrotoga cultures has limited our understanding of their physiological and genomic characteristics. Here, we isolated the ‘ Ca . Nitrotoga’ sp. strain AM1P, from a previously enriched Nitrotoga culture, using an improved isolation strategy. Although ‘ Ca . Nitrotoga’ have been recognized as cold‐adapted NOB, the strain AM1P had a slightly higher optimum growth temperature at 23°C. Strain AM1P showed a pH optimum of 8.3 and was not inhibited even at high nitrite concentrations (20 mM). We obtained the complete genome of the strain and compared the genome profile to five previously sequenced ‘ Ca . Nitrotoga’ strains. Comparative genomics suggested that lactate dehydrogenase may be only encoded in the strain AM1P and closely related genomes. While the growth yield of AM1P did not change, we observed faster growth in the presence of lactate in comparison to purely chemolithoautotrophic growth. The characterization of the new strain AM1P sheds light on the physiological adaptation of this environmentally important, but understudied genus ‘ Ca . Nitrotoga’.