Phenotypic and Molecular Detection of Mycoplasma gallisepticum in Broiler and Layer Chickens in Some Egyptian Governorates

Abstract

Mycoplasma gallisepticum (MG) is a major avian pathogen revealing financial losses in poultry industry around the world. The current research aimed to study the bacteriological, molecular detection and sequencing of MG recovered from cases with chronic respiratory disease (CRD) from broiler and layer chicken farms in some Egyptian governorates. Therefore, a total of 125 samples were collected from (25) flock/governorate, representing (15) broiler chicken and (10) laying chicken farms from five Egyptian governorates (Giza, Al-Qalyubia, AL-Dakahlia, Al-Faiyum, AL-Sharqia) from March 2020 till January 2022. The isolates were characterized by using conventional methods and molecularly identified by using (16S rRNA), (mgc2) specific primers for MG. The bacteriological isolation showed that 80.8% (101/125) samples appeared as fried egg colonies on PPLO agar while the rest 24 samples were negative. Only 88 out of 101 (87.1%) bacteriologically positive samples were positive by conventional PCR. Gene target sequencing (GTS) was carried out on one MG isolate with positive PCR mgc2 specific gene. The incidence of MG increases in winter and autumn compared to summer and spring. The sequenced isolate of mgc2 gene is grouped with field strain isolated from Egyptian chickens with 100% identity. The obtained findings indicated that the mgc2 gene could discriminate between MG field type and vaccinal F-strain, MG remains a serious avian pathogen and the study recommend a periodical molecular monitoring of MG in poultry flock with sequence analysis of the circulating strains and further investigations should be applied to detect most suitable control and preventive measures to solve such problem.