Rapid detection of Mycoplasma bovis in milk samples and nasal swabs using the polymerase chain reaction.
Two methods are suggested that allow direct detection of Mycoplasma bovis from milk and nasal swabs, respectively. Milk samples were trypsinized in the presence of Triton X-100 and passed through a DNA-binding filter membrane, from which DNA was extracted and subjected to the polymerase chain reaction (PCR). The detection limit was 500 cfu/ml on agarose gels and 50 cfu/ml after Southern hybridization, which indicates that the method can be used to monitor low-titre samples from animals at the subclinical stage. Results were available within 24 h, thus rendering the procedure more rapid than ELISA and culture techniques. Six other methods designed for milk or other complex samples were tested, but were found to be unsatisfactory. Rapid and specific detection of the pathogen by PCR from nasal mucus treated with lysis buffer and proteinase K was demonstrated for swabs taken from experimentally-infected calves. It is concluded that the methods represent useful tools for effective livestock monitoring and single-animal diagnosis.