Abstract: Background – ‘Candidatus Mycoplasma haemominutum’ (CMh) is the most common feline hemoplasma but is generally considered a non-pathogen. However, in some clinically affected cats, CMh appears to be a primary pathogen. Hypothesis/Objectives – Different strains of CMh exist within regions that vary in virulence. Animals – Stored EDTA blood samples submitted to our laboratory that had been stored at -80C until assayed in this study. The samples came from healthy cats being screened as blood donors or from clinically ill cats with fever or anemia. Methods – Samples were assessed for DNA of the 3 feline hemoplasmas by PCR assay that targets the 16S rRNA gene. Samples positive for CMh and no other pathogens were sequenced and the data were compared by BLAST analysis. Phylogenetic analysis was performed in Geneious Prime and exported into MEGA 11 for phylogenetic construction. Clinical histories were determined by review of the medical record. Results – Positive results were obtained for 6 healthy cats and 9 clinically ill cats and sequences showing 98-100% homology to other CMh reported in GenBank. When clinical histories were evaluated, 4 of the 9 cats had findings suggesting that CMh was a primary pathogen. However, clustering differences amongst healthy cats and cats with histories suggesting different CMh manifestations were not apparent. Conclusions and clinical importance – Clinical findings potentially associated with CMh cases assessed here suggest that virulence can vary amongst strains in a region. Phylogenetic analysis being repeated with a longer segment of the 23S gene.
