Traditional and recent techniques were used for diagnosis of avian mycoplasmas in chickens showing respiratory manifestations from different farms in menofia governorate. A total of 57 isolates were recovered from examined organs of 100 chickens at 45-50 days old. The recovered isolates were classified into 3 acholeplasma and 54 Mycoplasma isolates, of which 52 isolates were identified as M. gallisepticum.
100 serum samples were collected from all chickens and examined by serum plate agglutination test (SPA) and 90 of these samples were tested by enzyme-linked immunosorbent assay (ELISA). The results of SPA test were, 65 positive, 9 suspected and 26 negative. The results of ELISA using M. gallisepticum coated plate (KPL kit ) were. 57 positive, 16 suspected and 17 negative.
Sodium dodecyl-sulfate polyacrylamide gel electrophoresis and western-blot technique were used to differentiate between two M. gallisepticum reference strains (F &S6) and two M. gallisepticum field isolates. The 4 strains of M. gallisepticum were similar in SDS-PAGE patterns and in their immunoreactions of proteins with minor differences.
Polymerase chain reaction (PCR) was used to compare between M. gallisepticum reference strains and M. gallisepticum field isolates. It gave two different results when two different primer sets were used, the first primer gave a specific band at 615 bp, which is specific for M. oral but not for M. gallisepticum.The second primer gave a specific band at 330 bp which is specific for M.gallisepticum.