Molecular epidemiology of isolated Mycoplasma bovis strains from clinical mastitis infections in Cattle

Mycoplasma bovis is one of the main pathogenic species and the most common cause of pneumonia, mastitis and arthritis in cattle. The aim of this study was to evaluate the epidemiological factors (age, level of production,herd size, type of discharge, drop in production and a history of clinical mastitis) in isolated Mycoplasma bovis strains from clinical mastitis infection in cattle. Samples from 328 cows with clinical mastitis were taken by purposive samplingmethod, and were sent with ice and up to 24 hours to Mycoplasma reference laboratory, Razi Vaccine and Serum Institute of Karaj. Isolation and identification by culture and PCR methods was done, Mycoplasma bovis was isolated and 31 isolates were confirmed by nucleotide sequencing method. One of the isolates had 100 percent genetic relationship with reference strain of Mycoplasma bovis PG45 ATCC25523. Also, one of the isolates was different in nucleotide sequence with other isolates and the rest had 99.7% homology. Most positive cases were present in the age group 4-6 years and 800 cattle herd size and in this sense there was a statistically significant difference between samples (P0.05). The results showed that the mammary secretions could not be definitivediagnosis of this type of mastitis. Also, more positive samples had one of mastitis in their history. The results showed the presence of Mycoplasma bovis in milk samples is significant in clinical mastitis of cows in Iran and principles of biosecurity and quarantine should be at the top of Mycoplasma bovis infection control programs.