Abstract:
Mycoplasma species are the main important causative agents causing pneumonia in cattle, there are about 200 species or more. The current work aimed to investigate various mycoplasma spp. isolated from the respiratory tract of cattle by microbial culture, conventional polymerase chain reaction technique, and target gene sequencing with phylogenetic analysis. An initial screening was done to confirm the presence of mycoplasma spp. by culture on PPLO's agar, digitonin sensitivity and biochemical tests. 129 isolates were characterized by fried egg with depressed center colonies, digitonin sensitive and negative to glucose fermentation and arginine utilization test. Out of 305 samples, 20 samples were selected for amplification by PCR technique using Mycoplasma 16S rRNA primer. Seven samples were positive to Mycoplasma species and gave amplified band at 1013 bp. subsequently, the seven isolates were sequencing. Four sequenced isolates (EGS1, EGL6, EGL1 and EGS2) were closely related to each other and very close to Mycoplasma bovis strains and far from M. leachii 99/014/6. Two sequenced isolates (EGL2 and EGL5) were closely related to each other and very close to Mycoplasma bovirhinis strains and far from M. leachii 99/014/6. One sequenced isolate (EGL3) was very close to Mycoplasma arginini strain and far from M. bovis 99/014/6. From these results, we conclude that conventional culture methods for diagnosis either by isolation and identification of Mycoplasma is a time-consuming method to diagnose mycoplasma infection So, these methods can be replaced by PCR and genome analysis technology.