Mycoplasma anserisalpingitidis sp. nov., isolated from European domestic geese (Anser anser domesticus) with reproductive pathology.

In 1983, Mycoplasma sp. strain 1220 was isolated in Hungary from the phallus lymph of a gander with phallus inflammation. Between 1983 and 2017, Mycoplasma sp. 1220 was also identified and isolated from the respiratory tract, liver, ovary, testis, peritoneum and cloaca of diseased geese in several countries. Seventeen studied strains produced acid from glucose and fructose but did not hydrolyse arginine or urea, and all grew under aerobic, microaerophilic and anaerobic conditions at 35 to 37 ˚C in either SP4 or pleuropneumonia-like organism medium supplemented with glucose and serum. Colonies on agar showed a typical fried-egg appearance and transmission electron microscopy revealed a typical mycoplasma cellular morphology. Molecular characterization included analysis of the following genetic loci: 16S rRNA, 23S rRNA, 16S-23S rRNA ITS, rpoB, rpoC, rpoD, uvrA, parC, topA, dnaE, fusA and pyk. The genome was sequenced for type strain 1220T. The 16S rRNA gene sequences of studied strains of Mycoplasma sp. 1220 shared 99.02-99.19 % nucleotide similarity with M. anatis strains but demonstrated ≤95.00-96.70 % nucleotide similarity to the 16S rRNA genes of other species of the genus Mycoplasma. Phylogenetic, average nucleotide and amino acid identity analyses revealed that the novel species was most closely related to Mycoplasma anatis. Based on the genetic data, we propose a novel species of the genus Mycoplasma, for which the name Mycoplasma anserisalpingitidis sp. nov. is proposed with the type strain 1220T (=ATCC BAA-2147T=NCTC 13513T=DSM 23982T). The G+C content is 26.70 mol%, genome size is 959110 bp.

Evaluation of protective efficacy of inactivated Mycoplasma synoviae vaccine with different adjuvants.

Mycoplasma synoviae (MS) is a poultry pathogen with a reported distribution throughout the world. Vaccination is utilized as an important component of MS control programs for MS infection. The aim of this study was to evaluate protection efficacy of an inactivated MS vaccine (MS bacterin) with different adjuvants in broilers against a Chinese field isolate (CHN-BZJ2-2015). Vaccination with adjuvants ISA 71 VG and chitosan, respectively, enhanced specific lymphocyte proliferation responses and upregulated the expression of IL-1ß, IL-6, IL-2 and IFN-γ prior to challenge. Furthermore, vaccination with adjuvant ISA 71 VG elicited the highest antibody titers, exhibited significantly lower air sac, foot pad and tracheal lesions than the other groups (P < 0.05), and decreased MS colonization. These results demonstrated that inactivated MS vaccine with ISA 71 VG is able to induce both cellular and humoral immune response in broilers and confers a high level of protection upon challenge, demonstrating a potential application in the field.

Interplay Between the Phenotype and Genotype, and Efflux Pumps in Drug-Resistant Strains of Riemerella anatipestifer.

The number of multidrug-resistant strains of Riemerella anatipestifer continues to increase, and new strategies for the treatment of associated infections are necessary. Recently, numerous studies have shown that efflux pumps (EPs) play key roles in universal bacterial mechanisms that contribute to antibiotic resistance. In addition, studies have shown that the effects of antibiotics that are subjected to efflux can be reinforced by their combined use with efflux pump inhibitors (EPIs). Unfortunately, the role of the efflux system in R. anatipestifer remains barely understood. In this study, we evaluated the role of EPs and resistance genes in the resistance generated by clinical strains of R. anatipestifer to antibiotics. A set of 10 R. anatipestifer strains were characterized by drug resistance, associated resistance genes, and antibiotic profiles in the presence and absence of EPIs. Efflux activity was studied on a real time basis through a fluorometric method. Quantification of the levels of mRNA transcription of efflux pump genes (EPGs) was determined by RT-qPCR. Several approaches (detection of resistance genes, drug susceptibility testing, and growth kinetics analysis) were used to assess the correlation between the effect of the EPIs and the resistance levels. Analysis of the R. anatipestifer growth inhibition tests showed that the antibiotic activity was enhanced by the synergy of EPIs. Among the various resistance genes that confer antibiotic resistance, different minimum inhibitory concentrations (MICs) were observed. The different levels of resistance were reduced by EPIs. Real time fluorometry showed that all the R. anatipestifer strains presented inherent efflux activity, conferring varying levels of inhibition in the presence of EPIs. Moreover, 15 EPGs were overexpressed in the presence of antibiotics. The addition of EPIs to antibiotics led to downregulation in the expression of some EPGs and a simultaneous increase in drug resistance and sensitivity. These results demonstrated the contribution of these EPs in the resistant phenotype of the clinical strains of R. anatipestifer that are under investigation, independently of the resistant genotype of the respective strains. Intrinsic efflux activity was possibly linked to the evolution of resistance in multidrug-resistant isolates of R. anatipestifer. Furthermore, the inhibition of EPs by EPIs could enhance the clinical effects of antibiotics.

The Strategy of Picornavirus Evading Host Antiviral Responses: Non-structural Proteins Suppress the Production of IFNs.

Viral infections trigger the innate immune system to produce interferons (IFNs), which play important role in host antiviral responses. Co-evolution of viruses with their hosts has favored development of various strategies to evade the effects of IFNs, enabling viruses to survive inside host cells. One such strategy involves inhibition of IFN signaling pathways by non-structural proteins. In this review, we provide a brief overview of host signaling pathways inducing IFN production and their suppression by picornavirus non-structural proteins. Using this strategy, picornaviruses can evade the host immune response and replicate inside host cells.

The effects of the context-dependent codon usage bias on the structure of the nsp1α of porcine reproductive and respiratory syndrome virus.

The information about the crystal structure of porcine reproductive and respiratory syndrome virus (PRRSV) leader protease nsp1α is available to analyze the roles of tRNA abundance of pigs and codon usage of the nsp1 α gene in the formation of this protease. The effects of tRNA abundance of the pigs and the synonymous codon usage and the context-dependent codon bias (CDCB) of the nsp1 α on shaping the specific folding units (α-helix, ß-strand, and the coil) in the nsp1α were analyzed based on the structural information about this protease from protein data bank (PDB: 3IFU) and the nsp1 α of the 191 PRRSV strains. By mapping the overall tRNA abundance along the nsp1 α, we found that there is no link between the fluctuation of the overall tRNA abundance and the specific folding units in the nsp1α, and the low translation speed of ribosome caused by the tRNA abundance exists in the nsp1 α. The strong correlation between some synonymous codon usage and the specific folding units in the nsp1α was found, and the phenomenon of CDCB exists in the specific folding units of the nsp1α. These findings provide an insight into the roles of the synonymous codon usage and CDCB in the formation of PRRSV nsp1α structure.

Epstein-Barr virus (HHV-4) inoculation to rabbits by intranasal and oral routes results in subacute and/or persistent infection dissimilar to human disease.

OBJECTIVE: We report the infection of New Zealand white rabbits with Epstein-Barr virus (EBV). METHODS: EBV prepared in B95-8 (producer) cells was inoculated to rabbits by combined intranasal and oral routes. Blood and white blood cell (WBC) samples were taken before infection, then on days 8, 28 and 98 post-infection (p.i.). RESULTS: Administration of either 3 × 10(8) (group A, 11 rabbits) or 1 × 10(9) (group B, 10 rabbits) EBV DNA copies per animal induced subacute and/or persistent infection. The IgG antibodies in plasma were detected by ELISA as well as by immunoblot (IB). The IB bands showed mainly antibodies to the BZRF1/Zta transactivation polypeptide (69.2%), the p54 early protein (53.4%) and to the p23 capsid protein (35.8%). No anti-EBNA1 antibody was detected throughout. Viral DNA could be detected by PCR in WBCs and/or spleen of 7 out of 21 infected rabbits (30%), while 60-80% of them showed serologic response. The transiently present EBV DNA was accompanied by LMP1 antigen. CONCLUSIONS: Rabbits developed persistent EBV infection in the absence of EBNA1 antibodies and by the lack of typical infectious mononucleosis-like syndrome. The absence of EBNA1 antibody may reflect the lack of EBNA1 in B cells of EBV-inoculated rabbits.

Clustering of low usage codons in the translation initiation region of hepatitis C virus.

The adaptation of the overall codon usage pattern of hepatitis C virus (HCV) to that of human is estimated by the synonymous codon usage value (RSCU). The synonymous codon usage biases for the translation initiation region (TIR) of this virus are also analyzed by calculation of usage fluctuation of each synonymous codon along the TIR (the first 30 codon sites of the whole coding sequence of HCV). As for the overall codon usage pattern of HCV, this virus has a significant tendency to delete the codons with CpG or TpA dinucleotides. Turning to the adaptation of the overall codon usage of HCV to that of human, over half part of codons has a similar usage pattern between this virus and human, suggesting that the host cellular environment of the overall codon usage pattern influences the formation of codon usage for HCV. In addition, there is no obvious phenomenon that the codons with relatively low energy tend to be highly selected in the TIR of HCV, suggesting that the synonymous codon usage patterns for the TIR of HCV might be not affected by the secondary structure of nucleotide sequence, however, the formation of synonymous codons usage in the TIR of HCV is influenced by the overall codon usage patterns of human to some degree.

Role of the GapA and CrmA cytadhesins of Mycoplasma gallisepticum in promoting virulence and host colonization.

Mycoplasma gallisepticum is an important avian pathogen that commonly induces chronic respiratory disease in chicken. To better understand the mycoplasma factors involved in host colonization, chickens were infected via aerosol with two hemadsorption-negative (HA(-)) mutants, mHAD3 and RCL2, that were derived from a low passage of the pathogenic strain R (Rlow) and are both deficient in the two major cytadhesins GapA and CrmA. After 9 days of infection, chickens were monitored for air sac lesions and for the presence of mycoplasmas in various organs. The data showed that mHAD3, in which the crmA gene has been disrupted, did not promote efficient colonization or significant air sac lesions. In contrast, the spontaneous HA(-) RCL2 mutant, which contains a point mutation in the gapA structural gene, successfully colonized the respiratory tract and displayed an attenuated virulence compared to that of Rlow. It has previously been shown in vitro that the point mutation of RCL2 spontaneously reverts with a high frequency, resulting in on-and-off switching of the HA phenotype. Detailed analyses further revealed that such an event is not responsible for the observed in vivo outcome, since 98.4% of the mycoplasma populations recovered from RCL2-infected chickens still display the mutation and the associated phenotype. Unlike Rlow, however, RCL2 was unable to colonize inner organs. These findings demonstrate the major role played by the GapA and CrmA proteins in M. gallisepticum host colonization and virulence.

Characterization of Pasteurella multocida strains isolated from geese.

Phenotypic and genotypic diversity of forty-two Pasteurella multocida isolates from geese were characterized by analysis of their capsular type, Heddleston serotype, biotype, fimbrial gene allele type, comparative outer membrane protein (OMP) electrophoresis patterns, and were analyzed using PCR for the presence of virulence-associated genes (toxA, tbpA, pfhA, hgbA, hgbB, nanH, nanB, fimA, hsf-1, and pmHAS). A sequence comparison of the thdF and rpoB housekeeping genes of twenty representative P. multocida strains from three different OMP groups demonstrated that seventeen strains were closely related phylogenetically to previously published strains of P. multocida subsp. multocida and P. multocida subsp. gallicida, and only three strains from geese were grouped with previously published strains of P. multocida subsp. septica. This study is the first report regarding the characterization of phenotypic and genotypic features of different P. multocida field strains isolated from geese with the different clinical representation of pasteurellosis and provide our overview on the usefulness of these in vitro tests for primary characterization of P. multocida strains for the epidemiological studies of fowl cholera.

Short communication: role of Mycoplasma arginini in mastitis caused by Streptococcus dysgalactiae.

We performed a comparative study on the development of mastitis induced by Mycoplasma arginini or Streptococcus dysgalactiae after challenging the cows. Mycoplasma arginini did not cause any clinical symptoms on its own, resulting in only a transient increase of somatic cell count (SCC; increase ranging from 0.5 × 10(6) to 0.8 × 10(6) cells/mL) and a slight decrease of milk production (10%) for 5 d. In contrast, Strep. dysgalactiae induced more severe clinical signs in animals and SCC increased to 1.60 × 10(6) to 2.11 × 10(6) cells/mL for 10 d. In addition, milk production decreased (22.9 to 27.0%) for 10 d. After 3 mo (2 mo after the first challenge), animals that were challenged previously with M. arginini were rechallenged with Strep. dysgalactiae. Severe clinical mastitis developed, with very high SCC (5.00 × 10(6) to 21.5 × 10(6) cells/mL), and a very significant reduction of milk production (28.6 to 68.7%), which lasted more than 4 wk, was observed. The severe clinical mastitis developed not only in cows inoculated with Strep. dysgalactiae andM. arginini in the same udder quarter but also in cows infected in the quarter previously not challenged with mycoplasma. Cows challenged first with Strep. dysgalactiae and rechallenged with M. arginini 2 mo later developed only slight changes in both SCC and milk production, similar to those when the cows were challenged with M. arginini alone. We conclude that M. arginini infection does not cause remarkable mastitis (characterized by decrease in milk production and increase of SCC) but it significantly predisposes animals to infection with Strep. dysgalactiae, leading to severe clinical mastitis.

The analysis of codon bias of foot-and-mouth disease virus and the adaptation of this virus to the hosts.

The synonymous codon usage patterns of open reading frame (ORF) in foot-and-mouth disease virus (FMDV), the similarity degree of the synonymous codon usage between this virus and the hosts and the genetic diversities of FMDV ORFs and the viral functional genes in viral ORF have been investigated by some simply statistical analyses. As for the synonymous codon usage of FMDV, some over-represented and under-represented codons have a similar usage in all seven serotypes. 33 out of 59 synonymous codons are similarly selected between FMDV ORF and the hosts. It is interesting that the overall codon usage pattern of the strains of serotype O isolated from pigs is different with that of strains of the same serotype isolated from non-pig origin, suggesting that the factor of pigs takes part in the formation of codon usage of FMDV serotype O. Projection of codon usage of nine viral functional genes onto the two-dimensional map represents that even though viral functional genes have various genetic diversities and each gene is not separated from each other based on seven serotypes, the codon usage patterns of VP2, 2C, 3A, 3C and 3D genes belonging to serotype O strains isolated from pigs are different with those of the same serotype strains from non-pig origin. In addition, the interaction between GC12% and GC3% of viral functional genes indicates that the codon usage patterns of VP1, VP2, 2B, 3A, 3C and 3D genes are influenced by mutation pressure from virus. Furthermore, distribution plots of ENC value vs. GC3% for viral function genes indicate that mutation pressure is not the only factor in the formation of codon usage of these genes. The results suggest that both the mutation pressure from virus and the translation selection from the hosts take part in the evolution process of viral functional genes of FMDV.

A comparative analysis on the synonymous codon usage pattern in viral functional genes and their translational initiation region of ASFV.

The synonymous codon usage pattern of African swine fever virus (ASFV), the similarity degree of the synonymous codon usage between this virus and some organisms and the synonymous codon usage bias for the translation initiation region of viral functional genes in the whole genome of ASFV have been investigated by some simply statistical analyses. Although both GC12% (the GC content at the first and second codon positions) and GC3% (the GC content at the third codon position) of viral functional genes have a large fluctuation, the significant correlations between GC12 and GC3% and between GC3% and the first principal axis of principle component analysis on the relative synonymous codon usage of the viral functional genes imply that mutation pressure of ASFV plays an important role in the synonymous codon usage pattern. Turning to the synonymous codon usage of this virus, the codons with U/A end predominate in the synonymous codon family for the same amino acid and a weak codon usage bias in both leading and lagging strands suggests that strand compositional asymmetry does not take part in the formation of codon usage in ASFV. The interaction between the absolute codon usage bias and GC3% suggests that other selections take part in the formation of codon usage, except for the mutation pressure. It is noted that the similarity degree of codon usage between ASFV and soft tick is higher than that between the virus and the pig, suggesting that the soft tick plays a more important role than the pig in the codon usage pattern of ASFV. The translational initiation region of the viral functional genes generally have a strong tendency to select some synonymous codons with low GC content, suggesting that the synonymous codon usage bias caused by translation selection from the host takes part in modulating the translation initiation efficiency of ASFV functional genes.

Effect of low-pathogenicity influenza virus H3N8 infection on Mycoplasma gallisepticum infection of chickens.

Mycoplasma infection is still very common in chicken and turkey flocks. Several low-pathogenicity avian influenza (LPAI) viruses are circulating in wild birds that can be easily transmitted to poultry flocks. However, the effect of LPAI on mycoplasma infection is not well understood. The aim of the present study was to investigate the infection of LPAI virus H3N8 (A/mallard/Hungary/19616/07) in chickens challenged with Mycoplasma gallisepticum. Two groups of chickens were aerosol challenged with M. gallisepticum. Later one of these groups and one mycoplasma-free group were aerosol challenged with the LPAI H3N8 virus. The birds were observed for clinical signs for 8 days, then euthanized, and examined for the presence of M. gallisepticum in the trachea, lung, air sac, liver, spleen, kidney and heart, and for developing anti-mycoplasma and anti-viral antibodies. The LPAI H3N8 virus did not cause any clinical signs but M. gallisepticum infection caused clinical signs, reduction of body weight gain and colonization of the inner organs. These parameters were more severe in the birds co-infected with M. gallisepticum and LPAI H3N8 virus than in the group challenged with M. gallisepticum alone. In addition, in the birds infected with both M. gallisepticum and LPAI H3N8 virus, the anti-mycoplasma antibody response was reduced significantly when compared with the group challenged with M. gallisepticum alone. Co-infection with LPAI H3N8 virus thus enhanced pathogenesis of M. gallisepticum infection significantly.

Eosinophilic Fasciitis associated with Mycoplasma arginini infection.

Eosinophilic fasciitis (EF) with generalized sclerodermiform skin lesions developed over a 19-month period in a previously healthy 23-year-old man. Although we confirmed EF by skin histology and laboratory tests, the recurrent fevers and the clinical observation of sclerotic prepuce with urethritis indicated further bacteriological analysis by conventional microbiological and DNA-based tests. Urethra cultures were positive for an arginine-hydrolyzing mycoplasma and Ureaplasma urealyticum. The patient also had serum IgM antibodies to Mycoplasma pneumoniae using enzyme-linked immunosorbent assay (ELISA)-based qualitative detection. Mycoplasma arginini was isolated from two independent venous blood serum samples and was identified by conventional microbiological tests and sequencing of the 16S rRNA and rpoB genes (GenBank sequence accession numbers HM179555 and HM179556, respectively). M. arginini genomic DNA also was detected by species-specific PCR in the skin lesion biopsy sample. Treatment with corticosteroids and long-term courses of selected antibiotics led to remission of skin symptoms and normalization of laboratory values. This report provides the first evidence of EF associated with mycoplasma infection and the second report of human infection with M. arginini and therefore suggests that this mycoplasma infection might have contributed to the pathogenesis of the disease.

Concept and application of a computational vaccinology workflow.

BACKGROUND: The last years have seen a renaissance of the vaccine area, driven by clinical needs in infectious diseases but also chronic diseases such as cancer and autoimmune disorders. Equally important are technological improvements involving nano-scale delivery platforms as well as third generation adjuvants. In parallel immunoinformatics routines have reached essential maturity for supporting central aspects in vaccinology going beyond prediction of antigenic determinants. On this basis computational vaccinology has emerged as a discipline aimed at ab-initio rational vaccine design.Here we present a computational workflow for implementing computational vaccinology covering aspects from vaccine target identification to functional characterization and epitope selection supported by a Systems Biology assessment of central aspects in host-pathogen interaction. We exemplify the procedures for Epstein Barr Virus (EBV), a clinically relevant pathogen causing chronic infection and suspected of triggering malignancies and autoimmune disorders. RESULTS: We introduce pBone/pView as a computational workflow supporting design and execution of immunoinformatics workflow modules, additionally involving aspects of results visualization, knowledge sharing and re-use. Specific elements of the workflow involve identification of vaccine targets in the realm of a Systems Biology assessment of host-pathogen interaction for identifying functionally relevant targets, as well as various methodologies for delineating B- and T-cell epitopes with particular emphasis on broad coverage of viral isolates as well as MHC alleles.Applying the workflow on EBV specifically proposes sequences from the viral proteins LMP2, EBNA2 and BALF4 as vaccine targets holding specific B- and T-cell epitopes promising broad strain and allele coverage. CONCLUSION: Based on advancements in the experimental assessment of genomes, transcriptomes and proteomes for both, pathogen and (human) host, the fundaments for rational design of vaccines have been laid out. In parallel, immunoinformatics modules have been designed and successfully applied for supporting specific aspects in vaccine design. Joining these advancements, further complemented by novel vaccine formulation and delivery aspects, have paved the way for implementing computational vaccinology for rational vaccine design tackling presently unmet vaccine challenges.

Aerosol infection of calves with Histophilus somni.

The purpose of this study was to develop and evaluate an aerosol infection method with Histophilus somni that closely resembles the natural way of infection of calves. Another aim was to compare the virulence of two H. somni strains by collecting clinical and postmortem data of experimentally infected and control animals. Seventeen conventionally reared 3-month-old calves were divided into three groups. Two groups of six animals each were exposed to suspensions containing H. somni on three consecutive days using a vaporiser mask. The third group of five animals was used as control. The data of individual clinical examination were recorded daily. All animals were exterminated, and gross pathology of all lungs was evaluated on the 15th day after the first infection. Both H. somni strains caused an increase of rectal temperature, respiratory signs, decrease of weight gain, and severe catarrhal bronchopneumonia in both infected groups. Although some chronic lesions were detected in the lungs of the control animals as well, the histopathological findings in the infected and control groups were different. H. somni was recultured from all lungs in the challenged groups but it could not be reisolated or detected by PCR examination in the control group. This is the first paper on aerosol challenge of calves with H. somni using repeated infection and verified by detailed pathological, bacteriological and histopathological examination. The infection method proved to be successful. There was no difference in the virulence of the two H. somni strains used in the trial.

Salpingitis in geese associated with Mycoplasma sp. strain 1220.

An outbreak of disease in a White Rhine laying goose flock was characterized by increased water uptake, increased mortality, production of eggs with abnormal shells, a 25% drop in egg production and 40% embryo mortality. Affected dead or sacrificed birds had sero-fibrinogranulocytic peritonitis and salpingitis, infiltration of the lamina propria in the uterus and heterophil granulocytes in the isthmus and magnum of the oviduct. Mycoplasmas, mainly identified as Mycoplasma sp. strain 1220, were isolated from the airsac, liver, ovary, magnum and peritoneum of some affected geese. Strain 1220 was originally isolated from a Hungarian gander with phallus inflammation and, according to detailed biochemical and serological examinations, it is expected to represent a new avian species within the genus Mycoplasma.

Mycoplasma gallisepticum invades chicken erythrocytes during infection.

Recently, it was demonstrated using in vitro assays that the avian pathogen Mycoplasma gallisepticum is able to invade nonphagocytic cells. It was also shown that this mycoplasma can survive and multiply intracellularly for at least 48 h and that this cell invasion capacity contributes to the systemic spread of M. gallisepticum from the respiratory tract to the inner organs. Using the gentamicin invasion assay and a differential immunofluorescence technique combined with confocal laser scanning microscopy, we were able to demonstrate in in vitro experiments that M. gallisepticum is also capable of invading sheep and chicken erythrocytes. The frequencies of invasion of three well-defined M. gallisepticum strains were examined over a period of 24 h, and a significant increase in invasiveness occurred after 8 h of infection. In addition, blood samples derived from chickens experimentally infected via the aerosol route with the virulent strain M. gallisepticum R(low) were analyzed. Surprisingly, M. gallisepticum R(low) was detected in the bloodstream of infected chickens by nested PCR, as well as by differential immunofluorescence and interference contrast microscopy that showed that mycoplasmas were not only on the surface but also inside chicken erythrocytes. This finding provides novel insight into the pathomechanism of M. gallisepticum and may have implications for the development of preventive strategies.

Isolation of Mycoplasma capricolum-like strains from chickens.

Members of the genus Mycoplasma infect a wide range of hosts, but individual Mycoplasma species tend to exhibit a considerable degree of host specificity. We characterized Mycoplasma strain 700, isolated from a kidney of a layer hen in Spain and Mycoplasma strains ULB-A and ULB-B, isolated from the air sac and from the bile of stunted broiler chickens in Slovenia. The serologic examination showed that these three strains are antigenically unrelated to all of the recognized Mycoplasma species of avian origin, but closely related to the ruminant mycoplasma Mycoplasma capricolum subspecies capricolum (M. capricolum). The comparison of their 16S rRNA gene sequences with the sequence of M. capricolum (California kid) revealed 99.66% sequence identity for the strain 700 and 99.59% identity for strains ULB-A and ULB-B. Moreover, the predicted DnaK sequences of the M. capricolum-like strains, isolated from chickens, were identical to DnaK sequences of M. capricolum. Comparison of their dnaK gene sequences with M. capricolum showed 99.64% sequence identity for strain 700 and 99.27% identity for strains ULB-A and ULB-B. In the flock from which M. capricolum-like strains ULB-A and ULB-B were isolated, the majority of chickens (83% of the chickens examined) raised antibodies reacting with M. capricolum antigens. Notably, the infection of chickens with M. capricolum-like strains represents an unusual exception to the range of Mycoplasma species host specificity.

Induced expression of the antimicrobial peptide melittin inhibits experimental infection by Mycoplasma gallisepticum in chickens.

The in vivo action of the antimicrobial peptide melittin, expressed from a recombinant plasmid vector, on chickens experimentally infected with Mycoplasma gallisepticum was studied. The plasmid vector pBI/mel2/rtTA includes the melittin gene under the control of an inducible tetracycline-dependent human cytomegalovirus promoter and the gene coding for the trans-activation protein rtTA. Aerosol administration of the vector, followed by infecting the chickens with M. gallisepticum 1226, is shown to inhibit development of infection. The inhibitory action was confirmed by a complex of clinical, pathomorphological, histological and serological studies, and also by comparing the M. gallisepticum reisolation frequency from the respiratory tract and internal organs. The data suggest that plasmid vectors expressing genes of antimicrobial peptides can be considered as potential agents for the prevention and treatment of mycoplasma infections in poultry farming.