title: Biological characterization of Russian Mycoplasma gallisepticum field isolates.
abstract: An earlier study on commercial chickens and turkeys with a history of respiratory disease established Mycoplasma gallisepticum infection rates on 164 poultry farms of the Russian Federation. Forty-seven (29%) of these poultry farms were M. gallisepticum-positive by polymerase chain reaction but isolation of the mycoplasma was successful only on 10 farms. Five field isolates from different farms were selected for pathogenicity studies in specific pathogen-free chicks. Clinical signs, seroconversion, culture rates, air sac and tracheal lesions and mean tracheal mucosal thickness were all assessed in comparison with the reference strain, S6. Of the five isolates, MG140905 and MG070607 appeared to be slightly more pathogenic than the other three, as indicated by clinical signs, culture-positive rates and lesions, but only isolate MG140905 differed statistically (P < 0.05) from them, thus proving to be the most pathogenic. However, none of the Russian field isolates was as pathogenic as the S6 strain by the parameters measured. Stress or other factors such as concurrent bacterial or viral infections may have served as exacerbating factors for the disease seen in the naturally affected flocks. Sequence analysis of the gapA and mgc2 genes showed that MG140905 clustered with M. gallisepticum R(low) and was more distant from the majority of the Russian isolates.
authors.affiliation: Laboratory of Diagnosis of Viral Poultry Diseases, Federal Centre for Animal Health, Vladimir, Russia. spriginav@mail.ru
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Sprygin
authors.forename: Nikolay P
authors.initials: NP
authors.lastname: Elatkin
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Kolotilov
authors.forename: Mikhail S
authors.initials: MS
authors.lastname: Volkov
authors.forename: Marina I
authors.initials: MI
authors.lastname: Sorokina
authors.forename: Asya V
authors.initials: AV
authors.lastname: Borisova
authors.forename: Dmitriy B
authors.initials: DB
authors.lastname: Andreychuk
authors.forename: Nataliya S
authors.initials: NS
authors.lastname: Mudrak
authors.forename: Victor N
authors.initials: VN
authors.lastname: Irza
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Borisov
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Drygin
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics; D000400:Air Sacs / Q000473:pathology; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D002645:Chickens / Q000382:microbiology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D009175:Mycoplasma Infections / Q000382:microbiology / Q000662:veterinary*; D045686:Mycoplasma gallisepticum / Q000235:genetics* / Q000472:pathogenicity*; D011201:Poultry Diseases / Q000382:microbiology*; D011897:Random Allocation; D012426:Russia; D017422:Sequence Analysis, DNA; D013047:Specific Pathogen-Free Organisms; D014132:Trachea / Q000473:pathology; D014422:Turkeys / Q000382:microbiology*; D014774:Virulence
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C117938:GapA cytadhesin