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At least 19 recordsLinked to original sources
PubMed1993

Susceptibilities of Mycoplasma bovis, Mycoplasma dispar, and Ureaplasma diversum strains to antimicrobial agents in vitro.

The purpose of this study was to determine the susceptibility of various strains of Mycoplasma bovis, Mycoplasma dispar, and Ureaplasma diversum, which are prevalent causes of pneumonia in calves, to 16 antimicrobial agents in vitro. The MICs of the antimicrobial agents were determined by a serial broth dilution method for 16 field strains and the type strain of M. bovis, for 19 field strains and the type strain of M. dispar, and for 17 field strains of U. diversum. Final MICs for M. bovis and M. dispar were read after 7 days and final MICs for U. diversum after 1 to 2 days. All strains tested were susceptible to tylosin, kitasamycin, and tiamulin but were resistant to nifuroquine and streptomycin. Most strains of U. diversum were intermediately susceptible to oxytetracycline but fully susceptible to chlortetracycline; most strains of M. bovis and M. dispar, however, were resistant to both agents. Strains of M. dispar and U. diversum were susceptible to doxycycline and minocycline, but strains of M. bovis were only intermediately susceptible. Susceptibility or resistance to chloramphenicol, spiramycin, spectinomycin, lincomycin, or enrofloxacin depended on the species but was not equal for the three species. The type strains of M. bovis and M. dispar were more susceptible to various antimicrobial agents, including tetracyclines, than the field strains. This finding might indicate that M. bovis and M. dispar strains are becoming resistant to these agents. Antimicrobial agents that are effective in vitro against all three mycoplasma species can be considered for treating mycoplasma infections in pneumonic calves. Therefore, tylosin, kitasamycin, and tiamulin may be preferred over oxytetracycline and chlortetracycline.

Animals↗
PubMed2002

Identification and characterization of a site-specific tyrosine recombinase within the variable loci of Mycoplasma bovis, Mycoplasma pulmonis and Mycoplasma agalactiae.

Three highly mutable loci of the wall-less pathogens Mycoplasma bovis, Mycoplasma pulmonis and Mycoplasma agalactiae undergo high-frequency genomic rearrangements and generate extensive antigenic variation of major surface lipoproteins. Adjacent to each locus, an open reading frame exists as a single chromosomal copy and is predicted to encode a site-specific DNA recombinase exhibiting high homology to the recombinases XerD of Escherichia coli and CodV of Bacillus subtilis. Each of the mycoplasmal proteins are members of the lambda integrase family of tyrosine site-specific recombinases and likely mediates site-specific DNA inversions observed within the adjacent, variable loci.

Amino Acid Sequence↗
PubMed2005

Hydrogen peroxide production by Mycoplasma bovis and Mycoplasma agalactiae and effect of in vitro passage on a Mycoplasma bovis strain producing high levels of H2O2.

Hydrogen peroxide (H2O2) production and oxygen uptake during the oxidation of NADH and L-alpha-glycerophosphate (GP) by lysed cells was determined for the type and field strains of Mycoplasma bovis and M. agalactiae. NADH oxidation by all the strains showed variable production of H2O2 ranging from 0 to 1.21 mol/mol O2 taken up. All strains were unable to oxidize GP, showing absence of GP oxidase activity. Some strains were identified that produced relatively high levels of H2O2 (> 1.0 mol/ mol O2 taken up). In vitro passage of M. bovis strain 119B96 showed reduced H2O2 production: 0.52, 0.16, and 0.07 mol/mol O2 taken up after the 50th, 100th and 200th passages, respectively. SDS-PAGE analysis showed the loss of a protein band of 32 kDa after 50 passages. These preliminary studies show that not only does H2O2 production by potentially pathogenic Mycoplasma spp. vary in the field but also that similar alterations can be induced by passage in culture. In the latter case, at least in one M. bovis strain, this alteration has been shown by SDS-PAGE to be associated with a loss of specific protein production. Further study of these phenomena is essential background for the production of more efficient vaccines for mycoplasmas.

Animals↗
PubMed1997

Otitis media in preweaned Holstein dairy calves in Michigan due to Mycoplasma bovis.

Mycoplasma bovis was isolated from the tympanic bullae of dairy calves with an exudative otitis media. The history, clinical signs, gross and histologic lesions, and bacteriologic findings are described for 5 preweaned Holstein calves with otitis media from a 600-cow dairy in Michigan. Clinical findings consisted of unilateral or bilateral ear droop, epiphora, head tilt, and recumbency in severely affected calves. Postmortem examination revealed unilateral or bilateral fibrinosuppurative to caseous exudate in the tympanic bullae. Histologically, a marked fibrinosuppurative to caseous exudate filled the tympanic air spaces. The partially ulcerated tympanic mucosa was markedly thickened with mononuclear cell infiltration and proliferation of fibrous connective tissue. Bone remodeling and periosteal hyperostosis were present in some osseous septa. Mycoplasma bovis was isolated from the tympanic bullae of all 5 calves and from the lungs of 2 calves and the frontal sinus of 1 calf. Mycoplasma bovis was isolated at > 100,000 colony forming units/ml from the bulk milk tank of the farm of origin. The isolation of M. bovis from the bulk milk tank, indicating subclinical mycoplasmal mastitis coupled with the feeding of waste milk from mastitic cows to calves is suggestive of a possible source of the infection resulting in otitis media in preweaned dairy calves.

Animals↗
PubMed1989

Interaction of Mycoplasma bovis and Mycoplasma bovigenitalium with preimplantation bovine embryos.

In vitro exposures of bovine embryos to Mycoplasma bovis and Mycoplasma bovigenitalium were conducted to determine if these organisms adhered to the zona pellucida-intact (ZP-I) bovine embryo, and standard procedures for washing and treating embryos were evaluated to determine their effectiveness for removing or killing mycoplasmas. Mycoplasma bovis and M. bovigenitalium were isolated from 19 of 19 and 24 of 24 ZP-I embryos, respectively, after in vitro exposure and subsequent washing, thus demonstrating adherence of the two species of Mycoplasma to the ZP. Additionally, M. bovis was isolated from 20 of 20 and 23 of 23 embryos, while M. bovigenitalium was isolated from 25 of 25 and 22 of 22 embryos after antibiotic and trypsin treatment, respectively. It was concluded that neither of the standard procedures currently used for cleansing embryos should be relied upon for insuring freedom from mycoplasmas.

Journal Article↗
PubMed1997

Development of a specific DNA probe and PCR for the detection of Mycoplasma bovis.

Mycoplasma bovis is responsible for several production diseases in cattle, including mastitis, arthritis, pneumonia, abortion and infertility. Current methodologies for detecting and identifying M. bovis are time consuming and difficult. Tests which rely on antigen or antibody detection have poor sensitivity and specificity. In this paper associated protocols for the development of a hybridization probe and PCR are described. A genomic library (SauIIIA digested) was prepared from M. bovis DNA (Colindale Reference Strain: NC10131:02) and cloned into pUC19. Colony hybridization, using a probe preparation made from purified M. bovis DNA, was used to identify colonies of interest. M. bovis DNA fragments were retrieved from recombinant plasmids by digestion with EcoRI and HindIII. This DNA was used to prepare randomly primed probes for dot blot hybridization analysis with immobilized DNA from M. bovis (two strains), M. dispar, M. agalactiae, M. bovigenitalium (two strains), M. ovipneumoniae, a Group 7 strain, M. arginini and bacteria belonging to different genera. Four probes were found to hybridize only with M. bovis and M. ovipneumoniae DNA, whereas one probe reacted with genomic DNA from only one of the two M. bovis strains. The level of sensitivity of the dot blot hybridization assay was 200 CFU (colony forming units)/mL. To enhance the sensitivity further, an M. bovis-specific PCR assay was developed. The primers were designed using sequences obtained from the probe DNA which discriminated M. bovis from all other Mycoplasma DNA tested. The minimum amount of target DNA that could be detected by the PCR assay was that isolated from 10-20 CFU/mL. The PCR assay was therefore 10 times more sensitive than dot blot hybridization.

Animals↗
PubMed2005

The efficacy of valnemulin (Econor) in the control of disease caused by experimental infection of calves with Mycoplasma bovis.

Mycoplasma bovis infection was experimentally induced in groups of six young calves. A further group was uninfected and served as a control. Ten days after infection, medication with either enrofloxacin (Baytril, Bayer) or valnemulin (Econor, Novartis) was instituted via the milk replacer for a further 10 days, after which all calves were killed. Infection resulted in depression, pyrexia, inappetance and prominent respiratory signs. Arthritis occurred in two animals and two (unmedicated) animals died. At post-mortem examination extensive lesions were present in the lungs and M. bovis was re-isolated from infected unmedicated calves' lungs. Medication with either enrofloxacin or valnemulin resulted in a rapid diminution of clinical signs, restoration of appetite and reversal of weight loss. Isolation of Pasteurella multocida from the calves' lungs was suppressed by both medicaments. Valnemulin resulted in a more rapid reduction of clinical scores and eliminated M. bovis from the lungs more effectively than enrofloxacin.

Animals↗
PubMed2004

Characterization of a lympho-inhibitory peptide produced by Mycoplasma bovis.

Mycoplasma bovis is able to inhibit the mitogen-induced proliferation of bovine lymphocytes. Herein is described the isolation of an immuno-inhibitory peptide from M. bovis. Using size exclusion chromatography, three lympho-suppressive fractions were isolated from M. bovis free supernatant. MALDI-TOF analysis revealed a common peak throughout the suppressive fractions. The purest of these fractions was subjected to N-terminal sequencing, revealing an 84% homologous match with the C-terminus of the M. bovis surface protein VspL (variable surface protein-L). A recombinant of the 26 amino acid peptide was also able to suppress Concanavalin A (ConA)-induced proliferation of bovine lymphocytes. This describes a unique immunosuppressive peptide produced by the bovine respiratory pathogen, M. bovis.

Amino Acid Sequence↗
PubMed1993

Comparison of various diagnostic methods for the detection of Mycoplasma bovis.

Mycoplasma bovis, the main causative agent of mycoplasmal mastitis, arthritis and pneumonia in cattle, causes considerable economic losses. Veterinary hygiene measures would be most effective if introduced at an early stage, especially the culling of cows shedding the pathogen for the control of mastitis. It is therefore crucial to ensure that diagnostic methods are available which can perform rapid and specific detection of the agent at acceptable costs. Six different detection methods have been compared and evaluated in terms of performance parameters and suitability for routine diagnosis. Conventional M. bovis isolation and identification from culture is the only technique used for routine diagnosis at present. However, this process is rather laborious and time-consuming, and final results are available only after several days. Enzyme-linked immunosorbent assay (ELISA) techniques can be used to screen for M. bovis antibodies or antigens in clinically-diseased animals. Detection of the agent in subclinical cases was accomplished in pre-incubated samples by an antigen capture ELISA involving a monoclonal antibody. Whole-cell protein patterns generated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis were used to identify and classify field isolates. Nucleic acid hybridizations using probes of defined specificity were conducted both as filter dot blot assay and in solution with ribosomal ribonucleic acid as the target. The latter was found to be potentially suitable for the screening of biological samples, although problems due to high background and reduced specificity remained. Finally, the presence of M. bovis cells in culture supernatant and in milk samples was demonstrated using the polymerase chain reaction. This procedure is potentially superior to all others currently available, due to its high sensitivity, specificity and speed. However, a number of practical problems must be solved prior to full-scale introduction of this technique for routine diagnosis.

Animals↗
PubMed2001

Juxtaposition of an active promoter to vsp genes via site-specific DNA inversions generates antigenic variation in Mycoplasma bovis.

Mycoplasma bovis, the most important etiological agent of bovine mycoplasmosis, undergoes extensive antigenic variation of major and highly immunogenic surface lipoprotein antigens (Vsps). A family of 13 related but divergent vsp genes, which occur as single chromosomal copies, was recently found in the chromosome of M. bovis. In the present study, the molecular mechanism mediating the high-frequency phase variation of two Vsps (VspA and VspC) as representatives of the Vsp family was investigated. Analysis of clonal isolates exhibiting phase transitions of VspA or of VspC (i.e., ON-->OFF-->ON) has shown that DNA inversions occur during Vsp phase variation. The upstream region of each vsp gene contains two sequence cassettes. The first (cassette no. 1), a 71-bp region upstream of the ATG initiation codon, exhibits 98% homology among all vsp genes, while the second (cassette no. 2), upstream of cassette no. 1, ranges in size from 50 to 180 bp and is more divergent. Examination of the ends of the inverted fragments during VspA or VspC phase variation revealed that in both cases, a change in the organization of vsp upstream cassettes involving three vsp genes had occurred. Primer extension and Northern blot analysis have shown that a specific cassette no. 2, designated A(2), is an active promoter and that juxtaposition of this regulatory element to a silent vsp gene by DNA inversions allows transcription initiation of the recipient gene. Further genetic analysis revealed that phase variation of VspA or of VspC involves two site-specific DNA inversions occurring between inverted copies of a specific 35-bp sequence present within the conserved cassette no. 1. A model for the control of Vsp phase variation is proposed.

Antigenic Variation↗
PubMed2002

Outbreak of pneumonia and arthritis in beef calves associated with Mycoplasma bovis and Mycoplasma californicum.

During an outbreak of pneumonia and arthritis in beef calves and young cattle on a large farm in north-west Germany, Mycoplasma bovis and Mycoplasma californicum were isolated from tracheobronchial lavage fluids and synovial fluids. The microbiological findings in dead and living animals and the immunohistochemical demonstration of M californicum antigen in lung and arthritic joint tissue, indicated that under poor housing conditions and possibly other predisposing factors, this mycoplasma, like M bovis, can colonise the respiratory tract and may be able to cross the respiratory mucosal barrier to spread through an infected animal and cause systemic infections that may contribute to severe arthritis.

Animals↗
PubMed2000

Effect of Mycoplasma bovis and Mycoplasma bovigenitalium in semen on fertilization and association with in vitro produced morula and blastocyst stage embryos.

Frozen-thawed bovine semen contaminated with Mycoplasma bovis (M. bovis) or Mycoplasma bovigenitalium (M. bovigenitalium) at either a high (10(6) CFU/mL) or low (10(4) CFU/mL) concentration was used for bovine oocyte insemination. The resulting embryos were washed 10 times as recommended by the International Embryo Transfer Society (IETS) prior to isolation of agent. A total of 1494 oocytes was inseminated with contaminated sperm cells and 855 oocytes with uninfected control semen. There was a significantly higher proportion of embryos that developed to the blastocyst stage in control than in the mycoplasma exposed groups (P<0.05). Isolation of motile spermatozoa by swim-up procedure prior to insemination did not render sperm cells free of Mycoplasma spp. Although M. bovis was isolated from all washed embryos after the high exposure level, it was found in only 60% of the samples after the low exposure level. In contrast, M. bovigenitalium was isolated from 70 and 12% of washed embryos exposed to the high and low levels of microorganism, respectively. Using scanning electron microscopy, both microorganisms were detected in association with the surface of zona pellucida-intact embryos and with sperm cells. These results indicate that mycoplasmas present in semen can be transmitted through the IVF system and infect embryos. Furthermore, the experiments showed that supplementation of culture media with standard antibiotics and washing embryos as recommended by IETS were not effective in rendering IVF embryos free from M. bovis and M. bovigenitalium.

Acrosome↗
PubMed1995

In vitro amplification of the 16S rRNA genes from Mycoplasma bovis and Mycoplasma agalactiae by PCR.

Mycoplasma bovis and Mycoplasma agalactiae are two very closely related species which cause mastitis in cows and goats, respectively. M. bovis can also cause arthritis and respiratory disease in cattle. It has recently been shown that the 16S rRNA sequences differ only in 8 nucleotide positions between the two species [J.G. Mattsson, B. Guss and K.-E. Johansson (1994) FEMS Microbiol. Lett., 115: 325-328]. These nucleotide differences are distributed over the molecule in such a way that it is difficult to design specific identification systems, based on PCR only, for M. bovis and M. agalactiae. Two different PCR systems based on 16S rRNA sequence data have, however, been designed for these two species. The forward primers were identical in the two systems and complementary to a segment of the evolutionarily variable region V2. The reverse primers were complementary to the variable region V6, in which there are two nucleotide differences between M. bovis and M. agalactiae. The size of the PCR products, generated with these primers, was 360 bp. Cross-amplification was obtained with the two species in the heterologous PCR systems, but with approximately a 100-fold lower efficiency. Cross-amplification was not obtained with any other bovine or caprine mycoplasma except for Mycoplasma sp. strain A1343 of the caprine group 7. The detection limit of the PCR system for M. bovis with a reference culture was 4 x 10(2) CFU/ml and of the PCR system for M. agalactiae 2 x 10(2) CFU/ml. The M. bovis-PCR system was used to analyze nasal samples of calves from a herd where an outbreak of pneumonia had occured and it proved possible to detect M. bovis in these samples.

Animals↗
PubMed1998

Species identification of Mycoplasma bovis and Mycoplasma agalactiae based on the uvrC genes by PCR.

The DNA repair genes uvrC from Mycoplasma bovis and Mycoplasma agalactiae type strains were cloned and their nucleotide sequences were established. These sequences were used to design polymerase chain reaction (PCR) primer pairs for M. bovis and M. agalactiae. Each primer pair amplified a 1-6 kb fragment of the uvrC gene in the respective species. The specificity of the primer pairs for the two species was demonstrated through the lack of cross-amplifications in heterologous PCR reactions and in reactions using DNA from other mycoplasma species. Subsequent restriction enzyme analysis of the amplified uvrC gene segments from type and field strains of M. bovis and M. agalactiae showed that the uvrC genes are well conserved in both species but differ significantly between the two species. The diagnostic PCR assay enabled unambiguous identification of M. bovis and M. agalactiae strains isolated from geographically diverse places, even in cases where 16S rRNA gene sequence analysis was unable to discriminate between the two species.

Animals↗
PubMed1989

[Testing of a hyperimmune serum in calves infected intranasally with Mycoplasma bovis].

Mycoplasma (M.) bovis hyperimmune serum was subcutaneously injected to 16 of 26 calves repeatedly intranasally infected with M. bovis, during and/or after experimental infection. Antibody titres between 1:32 and 1:256 were recorded by means of indirect haemagglutination from the calves treated. Transmission of film-inhibitory antibodies failed to work. Neither clinical manifestations nor pathologico-anatomic alterations to the lungs of experimentally infected animals were mitigated by hyperimmune serum treatment. M. bovis, in high germ counts, was re-isolated from nasal swabs, trachea, pulmonary lymph nodes, and inflammatory lung tissue of both treated and untreated calves.

Animals↗
PubMed1991

Detection of Mycoplasma bovis and Mycoplasma agalactiae by oligonucleotide probes complementary to 16S rRNA.

The partial sequences of 16S rRNA from Mycoplasma bovis and M. agalactiae were determined by dideoxynucleotide sequencing using reverse transcriptase. Two oligonucleotides complementary to different evolutionary variable regions of 16S rRNA from these two species were synthesized. The oligonucleotides were end-labelled with 32P and used as probes in filter hybridization experiments with different bovine, caprine and ovine mycoplasmas as samples. One of the probes, complementary to a sequence of the V8-region of both M. bovis and M. agalactiae, did not cross-hybridize to any bovine, caprine or ovine mycoplasmas except M. bovigenitalium and M. californicum. This probe is thus not useful for analysis of bovine samples, but can be used for detection of M. agalactiae in samples from goats and sheep, since M. bovigenitalium and M. californicum have never been isolated from these hosts and M. bovis only occasionally. The other probe, complementary to a sequence of the V6-region of M. bovis, gave some cross-hybridization with M. agalactiae but not with bovine mycoplasmas. M. agalactiae has never been isolated from cattle and this probe is therefore useful for rapid screening of bovine samples for M. bovis.

Animals↗
PubMed1987

Detection of bovine serum antibody specific to Mycoplasma bovis and Mycoplasma californicum by enzyme-linked immunosorbent assay (ELISA).

ELISA for use in epidemiologic field studies of bovine mastitis, were developed to measure serum antibody to Mycoplasma bovis and M. californicum. Varying levels of serological cross-reactivity to seven heterologous bovine mycoplasmal species were demonstrated in each assay. Cross-reactivity was minimized by preincubation of cattle sera with suspensions of heterologous mycoplasma antigens, prior to measuring serum antibody to solid-phase antigen. Heterologous absorption improved the immunological specificity of the assays while avoiding the need to prepare species-unique antigens. Serum antibody was measured at one serum dilution. Test results were expressed as a ratio of the reactivity of a positive and a negative reference serum. A negative reference population (n = 127) was assembled. The percentile distribution of ELISA reactivity of these 127 sera were used to establish the classification criteria for each assay. The statistical methods used, while easily applied, were found to be sensitive to outlying values in the reference population. The resulting classification criteria provided controlled or known probabilities of false-positive misclassification in the two ELISA test systems. Sera from cattle with defined exposure histories were tested and classified according to these criteria.

Animals↗