engleski

Moraxella bovoculi isolated from a cattle with infectious bovine keratoconjunctivitis

Infectious bovine keratoconjunctivitis (IBK) is the most common eye disease of cattle that causes significant economic losses. Until now, IBK outbreaks in Croatia were mostly associated with Moraxella bovis, although some recent studies described cases caused by Moraxella bovoculi and Moraxella ovis. The aim of this study was to gain a better insight into the epizootiological situation in our country and to identify Moraxella spp. isolated from the herd with the current outbreak of IBK. The eye swab of an untreated heifer with clinical symptoms of IBK was inoculated on 5% horse blood agar and incubated at 37 °C for 24 h. Bacterial colonies were identified as Moraxella spp. based on morphological features and were subcultured for further identification and purification. For differentiating these bacteria, polymerase chain reaction (PCR) coupled with restriction fragment length polymorphism (RFLP) was performed. Genomic DNA was extracted and subjected to PCR using ISR primers (ISRdown: 5’-GTG AAG TCG TAA CAA GGT AGC CGT-3’ and ISRup: 5-ACC GAC GCT TAT CGC AGG CTA TCA-3’) for amplifying the 16S-23S intergenic spacer region (ISR). The differentiation of M. bovis from other species was based on the PCR product size. The obtained band size of ~600 bp was typical of M. bovoculi and M. ovis. Additionally, amplified DNA was digested with the enzyme AfaI in order to distinguish M. bovoculi from M. ovis. The resulting RFLP pattern was specific for M. bovoculi (~150 bp and ~450 bp). Additionally, the PCR product sequencing confirmed the identity of M. bovoculi. The results obtained in this study could explain the occasional failure of immunoprophylactic and/or treatment strategies against IBK described in some of the previous cases. Further research and typing of the obtained isolates would contribute to a better understanding of IBK pathogenesis, improvement of herd management and reduction of economic consequences.

Moraxella bovoculi, cattle, Croatia

nije evidentirano