Respiratory Pathogen Co-Detection in Hospitalised Cats: A Molecular and Clinical Study in a Biological Isolation and Containment Unit

Respiratory disease is a common cause of hospitalisation in cats and may involve the detection of multiple respiratory pathogens. However, the frequency and patterns of respiratory pathogen co-detection in hospitalised cats, and the clinical characteristics associated with multiple pathogen detection, remain poorly characterized. This study characterised the co-occurrence of respiratory pathogens in 150 cats admitted to a Biological Isolation and Containment Unit between March 2023 and May 2024 using singleplex and multiplex real-time PCR assays targeting SARS-CoV-2 and bacterial, fungal and viral respiratory pathogens, respectively. Pairwise respiratory pathogen co-detection patterns were characterised using a co-detection matrix, and multiple logistic regression was performed to identify factors independently associated with multiple respiratory pathogen detection. A total of 189 respiratory pathogen detections were recorded. Pasteurella multocida was the most frequently detected microorganism (n = 118; 78.7%), followed by Mycoplasma felis (n = 29; 19.3%). Multiple respiratory pathogen detection occurred in 48 out of 150 cats (32.0%) and was independently associated with feline respiratory disease complex as the primary reason for admission and infectious disease classification at admission. Pasteurella multocida was the microorganism most frequently involved in pairwise respiratory pathogen co-detections. These findings provide baseline molecular and clinical data to support further epidemiological investigations in hospitalised feline populations.