Feline respiratory disease: what is the role of Mycoplasma species?

PRACTICAL RELEVANCE: Non-hemotropic Mycoplasma species are frequently implicated in cases of respiratory disease, and also conjunctivitis, in cats. CLINICAL CHALLENGES: Mycoplasma species are considered commensal bacteria of the conjunctiva and the upper respiratory tract of cats, and hence their role as a primary pathogen is difficult to determine. These organisms certainly appear to play a significant role as a secondary pathogen in the upper airways, and there is increasing evidence that in some animals they may represent a primary infection. However, mycoplasmas have not been found in the lower airways of clinically healthy cats - suggesting that, when present, they likely represent a pathologic process. Diagnostic challenges exist as well; Mycoplasma species are not typically identified via cytology due to their small size, and culture of these organisms requires special media and handling. Although PCR has improved identification and allowed for speciation, conflicting culture and PCR results can create a dilemma regarding the clinical relevance of infection. EVIDENCE BASE: This article draws on original research and case reports to provide information about the role of Mycoplasma species in the feline upper and lower respiratory tract, diagnostic methods and associated challenges, and treatment options. AUDIENCE: The goal is to provide small animal practitioners with a current and organized review of the often-conflicting literature regarding the role of Mycoplasma species in feline respiratory infections. © ISFM and AAFP 2014.