Detection of Fusobacterium necrophorum Leukotoxin (lkta) gene sequence in the oral cavity of captive macropods

Fusobacterium necrophorum is an important aetiological agent of periodontal diseases (gingivitis and lumpy jaw) in captive macropods. The leukotoxin encoded by the lktA gene is a major virulence factor of F. necrophorum. In the present study, lktA gene sequences were detected by PCR in the oral cavity of 21/58 (36%) captive yellow footed rock wallabies and mainland tammar wallabies at two zoological parks in South Australia. This suggest that F. necrophorum encoded lktA may not be present in the oral cavity of all captive wallabies or that it is present at low levels, i.e. close to the limits of detection of conventional PCR. The lktA sequences had 98-100% homology to a sequence detected in ovine foot lesions infected with F. necrophorum. Cluster analysis of the partial lktA gene sequence revealed two clades of the lktA gene of F. necrophorum in macropods and calls for a detailed study using the whole gene sequence.