Detection of Mycoplasma agalactiae by culture and polymerase chain reaction (PCR) methods from Iranian goats

Abstract

Mycoplasma agalactiae is the etiological agent of contagious agalactia that is a serious disease affecting sheep and goats. It is characterized by mastitis and subsequent failure of milk production, arthritis and keratoconjunctivitis. The aim of the study was to detection of M. agalactiae by culture and polymerase chain reaction (PCR) methods from infected Iranian goats. For detection, a total of 57 samples were taken from conjunctiva (n=11), joint exudates (n=35) and milk secretion (n=11). After enrichment in PPLO broth media, identification of the Mycoplasma species was carried out by cultured and PCR method. Of the 57 samples in 9 samples (16%) fried egg colony appeared on the agar media. The PCR with mycoplasmal 16S rRNA was applied for detection of a variety of Mycoplasmaspecies. PCR identification of genus was successful in 31 isolates (54%) and showed specific amplicon at 163 bp. From this positive samples, 19 isolates were examined (61%) were positive for M. agalactiae that showed specific amplicon at 375 bp. Of the total samples, only in 3 samples both culture and genus PCR tests were positive and in 20 samples were negative. Whereas in 6 PCR negative samples Mycoplasma colony appeared on the agar media and this colonies did not observed in 28 PCR positive samples. This paper reported detection of M. agalactiae from goats for the first time in Iran. PCR can be used as trusty and supersede test in the detection of M. agalactiae from affected goats. Among different collecting sites, milk secretion samples are suitable for PCR detection of M. agalactiae. Key words: Mycoplasma agalactiae, goat, polymerase chain reaction, culture, Iran.