Involvement of Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) in respiratory disease in commercial chicken showing respiratory signs was investigated using polymerase chain reaction (PCR). Out of the 124 suspected cases, 50 (40.32%) were found to be positive for MG and 17 (13.70%) were positive for MS. The MG isolates were recovered from birds and subjected to antibiotic sensitivity testing by the broth microdilution method. Tilmicosin with MIC₉₀ and MIC₅₀ values of 3.12 and 6.25 µg/ml were found to be the most effective drug, followed by tylosin, erythromycin and enrofloxacin, all of which gave MIC₉₀ and MIC₅₀ values of 6.25 and 12.5 µg/ml respectively. Oxytetracycline and chlortetracycline were found to be the least effective drugs and the MIC₉₀ value for both these antibiotics was 100.0. The MIC values for various antibiotics recorded in this study were generally higher compared to those found in previous investigations.

To Cite This Article: Khatoon H, Afzal F, Tahir MF, Hussain M and Khan SU, 2018. Prevalence of mycoplasmosis and antibiotic susceptibility of Mycoplasma gallisepticum in commercial chicken flocks of Rawalpindi Division, Pakistan. Pak Vet J, 38(4): 446-448. http://dx.doi.org/10.29261/pakvetj/2018.081