Isolation and identification of Mycoplasma agalactiae by culture and polymerase chain reaction (PCR) from sheep of Qom province, Iran

Contagious agalactia (C.A) is an infectious syndrome of sheep that is characterized by mastitis and subsequent failure of milk production, arthritis, abortion and keratoconjunctivitis. Mycoplasma agalactiae (M. agalactiae) is the main cause of the disease in sheep. The aim of this study was isolation and identification of M. agalactiae with culture and polymerase chain reaction (PCR) assay from sheep of Qom province in Iran. A total of 102 samples were collected from milk secretion, eye, ear and joint exudates of sheep. All samples were cultured in PPLO broth supplemented for M. agalaciae isolation. The bacteria DNAs were extracted by phenol/chloroform method and the PCR assay was applied for detecting of Mycoplasma genus in 163bp fragment of 16S rRNA gene and M. agalactiae in 375bp fragment of lipoprotein gene from culture as same as in clinical samples. Out of the 102 samples, 19(18.63%) cultures were shown positive and typical Mycoplasma colonies in PPLO agar culture diagnostic method and 59(57.8%) were scored positive by Mycoplasma genus PCR, 19(18.62%) of the samples were scored positive by using M. agalactiae PCR as diagnostic method. Out of the 102 samples, 19 samples were shown both positive in the culture and PCR, 42 samples were shown both negative in the culture and PCR. 40 samples were negative in the culture and positive in PCR whereas only one sample was positive in culture and negative in PCR. The results showed that the more isolations of M. agalactiae were taken from milk and less in joint samples. M. agalactiae was one of the main factors of contagious agalactia that was detected for the first time from sheep in Qom province.