Use of a polymerase chain reaction for detection of Mycoplasma dispar in the nasal mucus of calves.

A polymerase chain reaction (PCR) assay was developed for the detection of Mycoplasma dispar in nasal mucus samples collected from calves. The target DNA sequence was the 16S rRNA gene, and the fragment was selected within a region of high polymorphism. The specificity and detection limit of the method were determined. This method was then used for the detection of M. dispar in nasal swabs collected from 301 calves, including 155 clinical samples from animals showing signs of respiratory disease and 146 samples from healthy animals. PCR with generic primers was applied to the detection of Mollicutes, followed by the detection of M. dispar. Mollicutes were detected in 52.05% of clinical samples from healthy animals and in 90.96% of samples from sick animals. Mycoplasma dispar was detected in 6.16% of healthy animals and in 34.84% of sick animals. The PCR assay was useful in verifying the presence of M. dispar in calves and may be a useful tool in monitoring this mycoplasma in cattle herds.

Rapid detection of Mycoplasma dispar and M. bovirhinis using allele specific polymerase chain reaction protocols.

We describe an allele specific PCR based approach for the rapid detection of two bovine Mycoplasma species associated with respiratory disease. Specific and universal oligonucleotides were used in combination to detect the presence of single nucleotide polymorphisms within the 16S ribosomal DNA sequence. Presence of Mycoplasma 16S rDNA is indicated by the production of a single control fragment, whilst positive samples generate an alternative smaller specific product over the same region. This technique provides a reliable and sensitive method which, although widely used in human genetic screening, has not been documented for diagnosis of bacterial infection.