Etiology of feline bronchial disease remains unknown so far. However, in human medicine, Mycoplasma spp. infections have been made responsible for the exacerbation of asthmatic lung disease for a long time.

Aim of this study was to investigate the relevance of Mycoplasma spp. infections for the development of chronic bronchitis/feline asthma. For this purpose, lavage samples of lungs and nose and nasal swabs where taken from cats with chronic bronchitis/feline asthma and from cats without respiratory disease serving as a control group.

Seventeen cats with clinical signs and 14 cats without respiratory disease were included in the study. The samples of both groups were cultured with a special Mycoplasma enhancement media. DNA was isolated, followed by a PCR to detect possible Mycoplasma infections and sequencing of positive samples.

In this study, a significantly higher number of Mycoplasma-spp. -positive samples in the BALF were detected by PCR than by bacterial culture. In the BALF of the patients with clinical signs, 35.3 % Mycoplasma-positive results were obtained by PCR, while in the control group, 50.0 % of samples were positive for Mycoplasma species. There was no significant difference when results of both groups were compared. Nasal flush samples of the patient group were negative for Mycoplasma organisms in PCR as well as in culture. In contrast to that, five positive samples were found within the control group. There was a significant difference regarding the Mycoplasma status of nasal samples between groups. Sequencing of all Mycoplasma-positive samples revealed Mycoplasma felis.

In this study, both cats with feline asthma/chronic bronchitis and healthy cats were tested positive for Mycoplasma spp. Mycoplasma organisms, therefore, seem to represent normal commensales of the respiratory tract in cats. Based upon these results they do not seem to be relevant for the development of feline asthma.