Isolation of Mycoplasma spp. from broiler flocks with respiratory syndrome in Mashhad, Iran

Mycoplasmosis is one of the most important diseases in the poultry industry. Its causative agent, mycoplasma has various species, which two of them, Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) are the most important species. Due to the enormous losses in the production farms of industrial poultry, achieving a rapid, accurate and definite diagnosis of mycoplasma is of great importance. An early and definite diagnosis can guarantee the farm management on keeping herd health. In many countries such as Iran, the disease and its complications have still remained as a serious problem. Given this issue, we decided to identify the mycoplasma infection from broiler poultry flocks through culture method. 150 carcasses of broiler chicken belonging to 50 broiler flocks were sampled in which the signs of air sacs involvement and secretions in the airways, trachea and bronchi were seen. Samples taken from trachea, palatine cleft, nasal passages and air sacs, were cultivated into PPLO liquid medium using membrane filters (0.45 micron). They were incubated at 37 °C and were examined for pH (color) changes for every 48 hours. During the first 24 hours after cultivation, every color change to yellow or dark visible with the bare eye was considered as bacterial contamination, therefore, the contaminated samples were removed from the incubator. The color change in the liquid media was compared with the uninoculated medium as negative control. If a color change was observed in the liquid media after 48h, subculture was done in the PPLO agar. The plates were incubated at 37 °C for 14 days. They were examined for mycoplasma colonies using a microscope with magnification of 10 in every other day. The results showed that out of 150 samples obtained from 50 broiler flocks, 16 (10.66%) were positive for mycoplasma, while in terms of contamination, 4 flocks (8%) were positive. The contamination of positive cultures was finally confirmed through PCR method with universal primer.