Revised Mycoplasma synoviae vlhA PCRs

Mycoplasma synoviae (MS) is an important pathogen of chickens and turkeys. In recent years sequence analysis of the partial MS variable lipoprotein and hemagglutinin A (vlhA) gene PCR product has been utilized routinely for MS strain genotyping. Several PCR assays have been proposed for the amplification of the conserved upstream region of the MS vlhA gene; however, in several clinical instances the published assays failed to generate vlhA PCR products from confirmed MS-positive cases. These occurrences hindered our capability to genotype those cases. In silico analysis of the published MS vlhA PCRs raised concerns, which were addressed by the design of revised MS vlhA PCRs. The published and revised assays were tested for their relative sensitivity and specificity with laboratory and clinical MS-positive samples. One of the revised MS vlhA PCRs (revised Hong) was demonstrated to be more sensitive and specific, and amplified all clinical samples analyzed in this study.     

Recombinant DNA probes for Mycoplasma synoviae

A genomic library was prepared from Mycoplasma synoviae (MS) strain WVU 1853 cloned in plasmid vector pUC8 and transformed in Escherichia coli host JM83. In dot blot assays, four transformed E. coli clones hybridized with 32P-labeled chromosomal DNA of MS but not with 32P-labeled chromosomal DNA of M. gallisepticum (MG) strain S6. In Southern hybridization, each of the CsCl-purified recombinant plasmid clones was shown to contain two MS DNA fragments between 1.0 to 2.3 kbp in length. 32P-Labeled probes prepared from each of the four recombinant plasmids hybridized in dot blot assays with MS strain WVU 1853 and nine MS field isolates but not with MG strains S6, K810, F2F10, four MG field isolates, and 15 other species of avian mycoplasmas.     

北京市鸡毒支原体和滑液囊支原体血清学调查

为了解北京市鸡毒支原体(Mycoplasma galliscepticum,MG)和滑液囊支原体(Mycoplasma synoviae,MS)感染情况,2019年从北京市10个区127个养鸡场(户),采集3 910份鸡血清样品,采用酶联免疫吸附试验(ELISA)进行MG和MS感染抗体检测。结果显示:北京市10个区均有不同程度的MG和MS感染,场群阳性率分别介于78.95%～100%、68.42%～100%,样品阳性率分别介于59.35%～93.13%、50.0%～94.53%,平均场群阳性率分别为89.0%和86.6%,平均样品阳性率分别为79.0%和75.6%;第三季度的场群阳性率和第二季度的样品阳性率最高,第四季度场群阳性率和样品阳性率最低(P0.01);110～180日龄的MG样品阳性率、251～320日龄的MS样品阳性率最高,462日龄以上均最低(P0.01);规模化商品鸡场的MG和MS场群阳性率和样品阳性率均最高(P0.01);蛋鸡的MG和MS样品阳性率均高于肉鸡(P0.01)。结果表明,北京市MG和MS感染较为严重,第二、三季度高发,110～320日龄鸡群、规模化商品鸡场和蛋鸡群感染尤其严重。结果提示,应采取包括加强生物安全管理、种鸡净化、疫苗预防和药物治疗在内的综合管理措施,有效控制该地区MG、MS的流行。     

Lyophilization of Mycoplasma synoviae hemagglutination antigen

Two hemagglutination (HA) antigens produced from Mycoplasma synoviae isolates WVU-1853m and FMT grown in Frey's mycoplasma broth were lyophilized for HA preservation. Some increase in the HA titer occurred following lyophilization.     

Turkey sinusitis: synergism between Mycoplasma synoviae and Mycoplasma meleagridis

Sinusitis was produced experimentally in turkeys after intrasinus inoculation with broth cultures of both Mycoplasma synoviae and Mycoplasma meleagridis. No evidence of sinusitis was observed in other turkeys exposed to each of these organisms separately- indicating pathogenic synergism with these mycoplasmas.     

Airsacculitis in turkeys exposed to Mycoplasma synoviae membranes

In studies to investigate the pathogenesis of mycoplasmal airsacculitis, exudative lesions were produced in turkeys by intra-air-sac inoculation with Mycoplasma synoviae cell membranes and viable organisms. Membrane inocula containing 5 mg of protein produced more severe lesions than inocula containing either 2.5 mg or 1 mg protein. Turkeys exposed to 5 mg of membrane protein developed moderately severe airsacculitis; those exposed to viable organisms developed markedly severe airsacculitis. Microscopic examinations revealed that membrane-induced lesions were generally similar to those resulting from infection but were less severe. At the termination of the study, 8 days after exposure, M. synoviae was isolated from respiratory tract tissues of all turkeys exposed to live organisms, but it was not isolated from any of those exposed to membranes or from unexposed control turkeys. Antibody against M. synoviae was demonstrated with the tube agglutination test in sera from turkeys exposed to membranes and those exposed to live organisms, but it was not demonstrated in sera from unexposed control turkeys.     

Detection of Mycoplasma synoviae in clinically normal pheasants

Mycoplasma synoviae was isolated from the tracheas of seven clinically normal pheasants found in the vicinity of a chicken farm infected with M synoviae, but not from 120 pheasants and partridges with respiratory disease. When specimens were examined by the polymerase chain reaction only two additional pheasants infected with M synoviae were identified, one healthy and one diseased.     

Genetic and antigenic relatedness between Mycoplasma gallisepticum and Mycoplasma synoviae

The two avian pathogens Mycoplasma gallisepticum and Mycoplasma synoviae were found, by Southern blot hybridization of their digested DNAs, to share genomic nucleotide sequences additional to those of the highly conserved ribosomal RNA genes. The assumption that some of the shared sequences encode for antigens or epitopes common to both mycoplasmas was supported by Western immunoblot analysis of cell proteins of one mycoplasma with specific antiserum to the other mycoplasma. Interestingly, the band patterns of reactive antigens were different for some of the M. gallisepticum strains, supporting the concept that the species is genotypically variable. The results of the present study may explain the cross-reactivity of the two mycoplasmas noted previously in a variety of routine serological tests.     

Epidemiological study on Mycoplasma synoviae infection in layers

Mycoplasma synoviae infection occurs worldwide in commercial poultry flocks and may result in severe economic losses. The prevalence of this mycoplasma in standard layers older than 60 weeks was studied in a French department and the characteristics of infected or free flocks were compared. The genomic profiles of isolates from 36 infected flocks were studied by pulsed-field gel electrophoresis and random amplified polymorphic DNA methods in order to investigate possible routes of transmission. The minimum inhibitory concentrations of antibiotics were determined. Results showed that infection was more frequent in multi-age farms. Egg production and mortality of infected flocks were respectively lower and higher than in non-infected flocks but the differences were not statistically significant. The genomic profiles of isolates were quite homogeneous, a feature which does not facilitate the understanding of routes of transmission. All isolates were susceptible to tetracyclines, macrolides (except erythromycin), spectinomycin and fluoroquinolones.     

Pathogenicity of Mycoplasma synoviae in chicken embryos.

Pathogenicity of Mycoplasma synoviae (MS) was examined in specific-pathogen-free (SPF) white leghorn chicken embryos. Six isolates of MS were inoculated into 7-day embryos via the yolk sac. Isolates were evaluated for gross and microscopic lesions through 19 days' incubation and for embryo lethality through 20 days' incubation. Isolates in decreasing order of lethality, from lowest to highest 50% embryo lethal dose, were WVU 1853, K1968, K1858, FMT, 92D8034, and F10-2AS. Embryo lethality was consistent with lesion incidence and severity. Embryo lethality did not correlate with previous results regarding pathogenicity of these same six isolates in SPF broiler chickens.     

Experimental infection of ducks with Mycoplasma synoviae

Specific-pathogen-free ducks 24 and 180 days old were inoculated intranasally with the WVU 1853 strain of Mycoplasma synoviae (MS). No significant gross lesions were found in the infraorbital sinus, trachea, or air sacs at 7 or 28 days postinfection (PI), although MS was recovered from all these organs. A few ducks responded serologically by developing agglutinating antibodies. MS multiplied in embryonated duck eggs but to lower titers than in embryonated chicken eggs.     

Immunoglobulin G Fc receptors of Mycoplasma synoviae

The objective of the study was to demonstrate and characterize IgG Fc receptors of Mycoplasma synoviae. Two IgG Fc receptors were recognized with molecular weights (MW) of 80,000 and 90,000 and isoelectric focusing points (pI) of 5.3 and 4.3, respectively. The activity of the IgG Fc receptors was eliminated by exposure to 0.1 unit of protease for 10 minutes. Mild reduction in activity was observed with trypsin between 100 to 1000 units for 10 minutes. The IgG Fc receptors were resistant to exposure to 60 C for 60 minutes and to 100 C for 20 minutes. The M. synoviae IgG Fc receptors were strongly reactive to affinity-purified Fc Fragment of chicken IgG; affinity-purified chicken IgG; and serum IgG of chicken, quail, pigeon, and turkey. A moderate reaction was detected to human affinity-purified IgG, and weak reactions were detected to affinity-purified IgG of cat, cow, dog, goat, guinea pig, horse, and rabbit. No reaction occurred with IgG of duck, goose, mouse, pig or rat.     

Restriction endonuclease analysis of Mycoplasma synoviae strains

A diverse group of Mycoplasma synoviae strains from various hosts, pathological processes, and geographic areas collected over about 25 years were analyzed by restriction endonuclease analysis. The results suggest that restriction endonuclease analysis of M. synoviae strains may be a useful strain identification tool to study epidemiological problems.     

应用多重套式PCR检测鸡毒支原体和鸡滑液囊支原体

根据已发表的鸡毒和鸡滑液支原体血凝素基因序列pMGA和vlhA各设计两对引物,建立鉴别诊断两种支原体的多重套式PCR方法,对其进行温度条件、Ⅱ步模板浓度优化及特异性、敏感性实验。该方法在两步PCR后能特异性地扩增出MG(408 bp)和MS(688 bp)两个目的片段。应用于临床样品检测,与支原体分离、SPA检测比较结果PCR灵敏度高于病原分离。     

Serological detection of Mycoplasma synoviae infection in turkeys.

The antibody response of turkeys experimentally infected with Mycoplasma synoviae was determined by the serum plate agglutination (SPA), hemagglutination-inhibition (HI), and microagglutination (MA) tests and the enzyme-linked immunosorbent assay (ELISA). No antibody response was detected until 2 weeks postinfection (PI) with the MA test (17% positive), 3 weeks PI with the SPA test (11% positive), 4 weeks with the HI test (21% positive), and 5 weeks PI with the ELISA, and even then, only 16% of the birds were positive. Although at least 89% of the birds were positive by culture, only 58% of the turkeys developed a detectable antibody response.