Subdivision of Mycoplasma mycoides subsp. mycoides from cattle and goats into two types

Vaccination of cattle with the N terminus of LppQ of Mycoplasma mycoides subsp. mycoides results in type III immune complex disease upon experimental infection

Contagious bovine pleuropneumonia (CBPP) is a serious respiratory disease of cattle caused by Mycoplasma mycoides subsp. mycoides. Current vaccines against CBPP induce short-lived immunity and can cause severe postvaccine reactions. Previous studies have identified the N terminus of the transmembrane lipoprotein Q (LppQ-N') of M. mycoides subsp. mycoides as the major antigen and a possible virulence factor. We therefore immunized cattle with purified recombinant LppQ-N' formulated in Freund's adjuvant and challenged them with M. mycoides subsp. mycoides. Vaccinated animals showed a strong seroconversion to LppQ, but they exhibited significantly enhanced postchallenge glomerulonephritis compared to the placebo group (P = 0.021). Glomerulonephritis was characterized by features that suggested the development of antigen-antibody immune complexes. Clinical signs and gross pathological scores did not significantly differ between vaccinated and placebo groups. These findings reveal for the first time the pathogenesis of enhanced disease as a result of antibodies against LppQ during challenge and also argue against inclusion of LppQ-N' in a future subunit vaccine for CBPP.

Disruption of the S41 peptidase gene in mycoplasma mycoides capri impacts proteome profile, H(2)O(2) production, and sensitivity to heat shock

Members of the Mycoplasma mycoides cluster are among the most virulent of the mycoplasmas, causing worldwide economically significant diseases of cattle and goats. A distinguishing phenotype among the members of the cluster is the ability to degrade casein. The MMCAP2_0241 gene, an S41 peptidase, confers the proteolytic phenotype in Mycoplasma mycoides subsp. capri GM12. In order to determine the impact of disruption of the gene, we used differential proteome profiling to compare the M. mycoides subsp. capri wild type with a mutant lacking the proteolytic phenotype. Disruption of MMCAP2_0241 resulted in altered phenotypes reminiscent of M. mycoides subsp. mycoides SC and had significant impacts on the proteome profile of the microbe. The mutant exhibited increased production of hydrogen peroxide, decreased lactate dehydrogenase activity, and increased sensitivity to heat shock.

Mycoplasma leachii sp. nov. as a new species designation for Mycoplasma sp. bovine group 7 of Leach, and reclassification of Mycoplasma mycoides subsp. mycoides LC as a serovar of Mycoplasma mycoides subsp. capri

The Mycoplasma mycoides cluster consists of six pathogenic mycoplasmas causing disease in ruminants, which share many genotypic and phenotypic traits. The M. mycoides cluster comprises five recognized taxa: Mycoplasma mycoides subsp. mycoides Small Colony (MmmSC), M. mycoides subsp. mycoides Large Colony (MmmLC), M. mycoides subsp. capri (Mmc), Mycoplasma capricolum subsp. capricolum (Mcc) and M. capricolum subsp. capripneumoniae (Mccp). The group of strains known as Mycoplasma sp. bovine group 7 of Leach (MBG7) has remained unassigned, due to conflicting data obtained by different classification methods. In the present paper, all available data, including recent phylogenetic analyses, have been reviewed, resulting in a proposal for an emended taxonomy of this cluster: (i) the MBG7 strains, although related phylogenetically to M. capricolum, hold sufficient characteristic traits to be assigned as a separate species, i.e. Mycoplasma leachii sp. nov. (type strain, PG50(T) = N29(T) = NCTC 10133(T) = DSM 21131(T)); (ii) MmmLC and Mmc, which can only be distinguished by serological methods and are related more distantly to MmmSC, should be combined into a single subspecies, i.e. Mycoplasma mycoides subsp. capri, leaving M. mycoides subsp. mycoides (MmmSC) as the exclusive designation for the agent of contagious bovine pleuropneumonia. A taxonomic description of M. leachii sp. nov. and emended descriptions of M. mycoides subsp. mycoides and M. mycoides subsp. capri are presented. As a result of these emendments, the M. mycoides cluster will hereafter be composed of five taxa comprising three subclusters, which correspond to the M. mycoides subspecies, the M. capricolum subspecies and the novel species M. leachii.

Detection of Mycoplasma mycoides sub-species mycoides small colony by a specific capture/enrichment monoclonal antibody-based sandwich ELISA

The present study describes the development of a specific Mycoplasma mycoides subsp. mycoides Small Colony (MmmSC) monoclonal antibody (MAb), 6E3, and its application in a sandwich ELISA (sELISA) format. Mab 6E3 reacted only to the 12 MmmSC within the 32 M. mycoides cluster strains and 12 representative strains of other bovine, ovine and caprine associated mycoplasmas examined. A capture/enrichment format of the sELISA that combined MAb 6E3 with a previously developed MAb 3H12 that cross reacted with Mmm Large Colony [Rodriguez, F., Ball, H.J., Finlay, D., Campbell, D., Mackie, D.P., 1996. Detection of Mycoplasma mycoides sub-species mycoides by monoclonal antibody-based sandwich ELISA. Veterinary Microbiology 51, 69-76], retained MmmSC specificity and improved the sensitivity from the 1.2x10(7)cfu/ml for a standard 2h capture stage sELISA down to as low as 2cfu/ml for a 72h capture. A low level of false positives (1%) was observed when this assay was applied to 200 bovine respiratory and milk samples submitted for diagnostic investigation. This simple and specific sELISA provides a suitable assay for screening large numbers of samples for CBPP.

Phylogeny of the Mycoplasma mycoides cluster based on analysis of five conserved protein-coding sequences and possible implications for the taxonomy of the group

A phylogenetic tree of the Mycoplasma mycoides cluster was inferred from a set of concatenated sequences from five housekeeping genes (fusA, glpQ, gyrB, lepA and rpoB). The relevance of this phylogeny was reinforced by detailed analysis of the congruence of the phylogenies derived from each of the five individual gene sequences. Two subclusters were distinguished. The M. mycoides subcluster comprised M. mycoides subsp. mycoides biotypes Small Colony (SC) and Large Colony (LC) and M. mycoides subsp. capri. The latter two groups could not be clearly separated, which supports previous proposals that they be united into a single taxonomic entity. The Mycoplasma capricolum subcluster included M. capricolum subsp. capricolum, M. capricolum subsp. capripneumoniae and Mycoplasma sp. bovine group 7 of Leach, a group of strains that remains unassigned. This group constituted a distinct branch within this cluster, supporting its classification as a subspecies of M. capricolum. Mycoplasma cottewii and Mycoplasma yeatsii clustered in a group that was distinct from Mycoplasma putrefaciens and they were all clearly separated from the M. mycoides cluster. In conclusion, this approach has allowed us to assign phylogenetic positions to all members of the M. mycoides cluster and related species and has proved the need to adjust the existing taxonomy. Furthermore, this method may be used as a reference technique to assign an unequivocal position to any particular strain related to this cluster and may lead to the development of new techniques for rapid species identification.

Distinctive repertoire of contingency genes conferring mutation- based phase variation and combinatorial expression of surface lipoproteins in Mycoplasma capricolum subsp. capricolum of the Mycoplasma mycoides phylogenetic cluster

The generation of surface variation among many divergent species of Mollicutes (mycoplasmas) occurs through stochastic expression patterns of diverse lipoprotein genes. The size and wide distribution of such variable gene sets in minimal (approximately 0.6- to 1.4-Mb) mycoplasmal genomes suggest their key role in the adaptation and survival of these wall-less monoderms. Diversity through variable genes is less clearly established among phylogenetically similar mycoplasmas, such as the Mycoplasma mycoides cluster of ruminant pathogens, which vary widely in host range and pathobiology. Using (i) genome sequences from two members of this clade, Mycoplasma capricolum subsp. capricolum and M. mycoides subsp. mycoides small colony biotype (SC), (ii) antibodies to specific peptide determinants of predicted M. capricolum subsp. capricolum gene products, and (iii) analysis of the membrane-associated proteome of M. capricolum subsp. capricolum, a novel set of six genes (vmcA to vmcF) expressing distinct Vmc (variable M. capricolum subsp. capricolum) lipoproteins is demonstrated. These occur at two separate loci in the M. capricolum subsp. capricolum genome, which shares striking overall similarity and gene synteny with the M. mycoides subsp. mycoides SC genome. Collectively, Vmc expression is noncoordinate and combinatorial, subject to a single-unit insertion/deletion in a 5' flanking dinucleotide repeat that governs expression of each vmc gene. All vmc genes share modular regions affecting expression and membrane translocation. In contrast, vmcA to vmcD genes at one locus express surface proteins with highly structured size-variable repeating domains, whereas vmcE to vmcF genes express products with short repeats devoid of predicted structure. These genes confer a distinctive, dynamic surface architecture that may represent adaptive differences within this important group of pathogens as well as exploitable diagnostic targets.

Within-herd spread of contagious bovine pleuropneumonia in Ethiopian highlands

Contagious bovine pleuropneumonia (CBPP) is a major threat for cattle health and production in Africa. This disease is caused by the small-colony type of Mycoplasma mycoides subspecies mycoides (MmmSC). Transmission occurs from direct and repeated contacts between sick and healthy animals. Veterinary services recently reported a resurgence of CBPP in the province of West Wellega, in the Ethiopian highlands. A research program was set up to estimate the epidemiological parameters of the within-herd infection spread. A follow-up survey was implemented in 71 sampled herds of the Boji district (West Wellega province). Fifteen herds were classified as newly infected and used in a serological- and clinical-incidence study. The overall 16-month cumulative sero-incidence risk was 34%. Clinical cases were recorded for 39% of the seropositive cattle; case-fatality risk was 13%. There was no evidence of benefit on infection spread of CBPP-control measures used locally by farmers (isolation or antibiotic treatments of sick animals). This might be related to a lack of power in the statistical analyses or to a quality problem for the medications used (and more generally, for health-care delivery in the Boji district).

Variable surface protein Vmm of Mycoplasma mycoides subsp. mycoides small colony type

A variable surface protein, Vmm, of the bovine pathogen Mycoplasma mycoides subsp. mycoides small colony type (M. mycoides SC) has been identified and characterized. Vmm was specific for the SC biotype and was expressed by 68 of 69 analyzed M. mycoides SC strains. The protein was found to undergo reversible phase variation at a frequency of 9 x 10(-4) to 5 x 10(-5) per cell per generation. The vmm gene was present in all of the 69 tested M. mycoides SC strains and encodes a lipoprotein precursor of 59 amino acids (aa), where the mature protein was predicted to be 36 aa and was anchored to the membrane by only the lipid moiety, as no transmembrane region could be identified. DNA sequencing of the vmm gene region from ON and OFF clones showed that the expression of Vmm was regulated at the transcriptional level by dinucleotide insertions or deletions in a repetitive region of the promoter spacer. Vmm-like genes were also found in four closely related mycoplasmas, Mycoplasma capricolum subsp. capricolum, M. capricolum subsp. capripneumoniae, Mycoplasma sp. bovine serogroup 7, and Mycoplasma putrefaciens. However, Vmm could not be detected in whole-cell lysates of these species, suggesting that the proteins encoded by the vmm-like genes lack the binding epitope for the monoclonal antibody used in this study or, alternatively, that the Vmm-like proteins were not expressed.

Mycoplasmas isolated from the respiratory tract of cattle and goats in Tanzania

A microbiological study of the mycoplasma flora in the respiratory tracts of cattle and goats in selected regions of Tanzania is described. In the examination of cattle, mycoplasmas were isolated from 60 (17.8%) of the 338 examined lung samples, 8 (47.1%) of the 17 lymph nodes, 4 (13.3%) of the 30 pleural fluid samples and 4 (3.9%) of the 103 nasal swabs examined. All the isolates were identified as Mycoplasma mycoides subsp. mycoides, Small Colony type except for one isolate from pleural fluid which was identified as Mycoplasma arginini. M. mycoides subsp. mycoides, Small Colony type was isolated from samples originating from Dodoma, Iringa, Mbeya, Morogoro and Shinyanga regions where outbreaks of contagious bovine pleuropneumonia had been reported. In the examination of goats, mycoplasmas were isolated from 54 (34.0%) of the 159 examined lung samples, 41 (18.1%) of the 226 nasal swabs and 4 (40.0%) of the 10 pleural fluid samples. The species demonstrated were Mycoplasma capricolum subsp. capripneumoniae, M. mycoides subsp. mycoides, Small Colony type Mycoplasma ovipneumoniae and M. Capricolum subsp. arginini. The isolation of M. capripneumoniae in the Coast and Morogoro regions confirmed the presence of contagious caprine pleuropneumonia in the regions.

Disease caused by Mycoplasma mycoides subspecies mycoides LC in Hungarian goat herds

The occurrence of a goat disease caused by Mycoplasma mycoides subsp. mycoides LC in Hungary is reported. The disease occurred in two goat herds in the spring of 1999. In one herd 25% of the 4-12 weeks old kids (10 animals) while in the other herd 33% of the 6-12 weeks old kids (20 animals) became affected. The goat kids developed polyarthritis. The most severe lesions developed in the carpal joints. All animals died after 3-8 days of disease. Four dead kids were necropsied. All of them had serofibrinous and purulent polyarthritis, and in two animals bronchopneumonia, fibrinous pleuritis and meningitis were also found. In the articular exudates the presence of mycoplasmas was detected by PCR using a general mycoplasma primer. Mycoplasmas were cultured from the joints of all animals, from the abdominal parenchymal organs of two kids and from the lungs of one animal. The cultured mycoplasmas grew in strikingly large colonies, proved to be glucose positive, arginine negative and phosphatase positive, and liquefied the coagulated serum. They survived incubation at 45 degrees C for more than 24 h. Based upon their biochemical properties, the results of the immunofluorescence (IF) and growth inhibition tests and the sequence analysis of the PCR product, the cultured strains were identified as M. mycoides subsp. mycoides LC. Animals purchased in the previous autumn had been introduced to both farms. The disease may have been introduced with asymptomatic carrier animals, as earlier no similar disease had been observed at either farm.

Molecular Epidemiology of Contagious Bovine Pleuropneumonia in Tanzania Based on Amplified Fragment Length Polymorphism and Pulsed-field Gel Electrophoresis Analysis

The genetic diversity of 60 field strains of Mycoplasma mycoides ssp. mycoides, small colony type (M. mycoides SC), comprising 56 isolates from cattle in Tanzania, one from Kenya, two from Botswana and one from Portugal, as well as the type (PG1T) and vaccine (T1-SR49) strains, was investigated. The strains were analyzed for variations in the EcoRI and Csp6I restriction sites in the genomic DNA using the amplified fragment length polymorphism (AFLP) technique, and variations in the BamHI restriction sites using pulsed-field gel electrophoresis (PFGE). Six AFLP types were detected among the analysed strains. The AFLP profiles of the type and vaccine strains were indistinguishable from each other. Indistinguishable AFLP profiles were found for 55 Tanzanian field strains, one of them isolated in 1990 and the other 54 isolated in 1998/1999, although one strain isolated in 1999 showed a different profile. Strains from different countries revealed different AFLP profiles. Six PFGE types were detected among the analysed strains, with all the 56 Tanzanian field strains displaying indistinguishable PFGE profiles. Strains from different countries revealed different PFGE profiles, and so did the type and vaccine strains. The strong genomic homogeneity among M. mycoides SC strains associated with outbreaks of contagious bovine pleuropneumonia in different regions of Tanzania suggests that the outbreaks of the disease in the 1990-99 period might have been caused by a single epidemic clone. Moreover, this study has demonstrated that AFLP and PFGE are potential tools for molecular epidemiological studies of M. mycoides SC infections.

Monoclonal antibody differentiation of Mycoplasma mycoides subsp. mycoides small-colony strains causing contagious bovine pleuropneumonia from less important large-colony strains

Monoclonal antibody (MAb) PK-2 inhibited the in vitro growth of nine Mycoplasma mycoides subsp. mycoides small-colony strains. In contrast to the results with polyclonal antisera, growth inhibition by MAb PK-2 was specific for M. mycoides subsp. mycoides small-colony strains and constituted a reliable means of distinguishing them from other mycoplasmas.

Effect of natural amphipathic peptides on viability, membrane potential, cell shape and motility of mollicutes

The antibiotic activity of ten amphipathic peptides was investigated in six species of mollicutes belonging to the genera Acholeplasma, Mycoplasma and Spiroplasma. A. laidlawii was the most sensitive and M. mycoides subsp. mycoides SC the most resistant. Animal defence peptides (cecropins A and P1, and magainin 2) proved to be less potent than bee-venom mellitin and most of the peptides produced by bacteria (globomycin, gramicidin S, surfactin and valinomycin) or fungi (alamethicin). Gramicidin S was by far the most active peptide, with minimal inhibitory concentrations ranging from 2 to 50 nM. Alamethicin, gramicidin S, mellitin and surfactin had a cidal effect, whilst cecropins, globomycin, magainin 2, polymyxin B and valinomycin proved to be static. The peptides altered the membrane potential of spiroplasma cells with a potency independent of their linear or cyclic structure. However, globomycin depolarized the plasma membrane only weakly, whilst polymyxin B, in order to be active, required prior hyperpolarization of the membrane. The peptides also induced the loss of cell motility and helicity in spiroplasmas, suggesting that motility and cell shape in these bacteria are coupled to the transmembrane electrochemical gradient. Globomycin, an inhibitor of signal-peptidase II, prevented the growth of spiroplasmas, M. gallisepticum, and M. genitalium, but not that of A. laidlawii and M. mycoides subsp. mycoides SC, although the latter also synthesized membrane lipoproteins. Inhibition of spiralin processing by globomycin was demonstrated in S. citri and S. melliferum, with a more pronounced effect in the second species.

An immunohistochemical method of detecting Mycoplasma species antigens by use of monoclonal antibodies on paraffin sections of pneumonic bovine and caprine lungs

Lung samples from pneumonic lesions in cattle and goats, naturally or experimentally infected with strains of the Mycoplasma mycoides cluster, were fixed in formalin and embedded in paraffin. An immunohistochemical technique using monoclonal or polyclonal antibodies was performed on tissue sections in order to detect Mycoplasma antigens. Four monoclonal antibodies (MAbs), one (2A3) raised against M. mycoides ssp. mycoides small colony (SC) and large colony (LC), two (1D3 and 5E5) against M. mycoides ssp. capri, and one (5A10) against M. bovis, were used. A range of polyclonal antibodies, raised to the individual subspecies of the M. mycoides cluster, and one to Pasteurella haemolytica, was also used. The MAb 2A3 showed positive immunostaining in lung sections from cattle and goats naturally and experimentally infected with M. mycoides ssp. mycoides SC and LC, but not with pneumonic lesions of cattle and goats due to other members of the M. mycoides cluster, M. bovis or Pasteurella spp. The MAb 1D3 showed immunostaining in lung sections from goats naturally and experimentally infected with M. mycoides ssp. capri, but again not with pneumonic lesions caused by other members of the M. mycoides cluster, M. bovis or Pasteurella spp. The MAb 5E5 immunoreacted in sections from pneumonic lesions from all animals infected with one of the three M. mycoides cluster subspecies used in the study, but not with M. bovis or Pasteurella infected tissue. Immunoreaction was mainly found in the cell debris around necrotic areas, as well as in macrophages, neutrophils and epithelial cells. The localization of antigens of the M. mycoides cluster using polyclonal antisera followed basically the same pattern as that obtained with the monoclonals. However, a wide cross reactivity was found between different antisera and relatively high background immunostaining was also seen, especially in necrotic areas. The results suggest that immunohistochemical methods using monoclonal antibodies are useful tools for the diagnosis and study of the pathogenesis of pneumonia caused by the Mycoplasmas of the M. mycoides cluster.

Phylogeny of the Mycoplasma mycoides cluster as determined by sequence analysis of the 16S rRNA genes from the two rRNA operons

The so-called Mycoplasma mycoides cluster consists of six species or subspecies of mycoplasmas (Mollicutes). These species are pathogenic for ruminants and some of them are of great concern in veterinary medicine. The members of the M. mycoides cluster have two rRNA operons (rrnA and rrnB). The nucleotide sequences of the 16S rRNA genes of 10 strains, representing all of the known species and subspecies of the M. mycoides cluster, were determined by direct automated solid-phase DNA sequencing. The sequences of both rRNA operons were determined by a novel strategy involving in vitro amplification by PCR with one operon-specific primer pair and one general primer pair. Interestingly, sequence differences (polymorphisms) between the two operons were observed for all strains. Two strains of M. capricolum subsp. capripneumoniae were sequenced, and 15 polymorphisms were found in the type strain (F38) and 17 polymorphisms were found in the other strain (4/2LC). Eight polymorphisms were found in the 16S rRNA genes of the M. mycoides subsp. mycoides small-colony type, and sequence length variations in a poly(A) region were observed in the 16S rRNA genes of the two operons of this species. Secondary-structure analysis showed that polymorphisms were present in both stem and loop regions. The nucleotide substitutions in the polymorphic sites of the stem regions often resulted in a change from a canonical to a noncanonical base pairing or vice versa. A compensatory mutation was never observed in the other nucleotide of the base pair. Phylogenetic analysis based on the 16S rRNA sequences indicated that Mycoplasma sp. strain PG50 should be included in the M. capricolum species group. Furthermore, the 16S rRNA sequences of M. mycoides subsp. capri and the M. mycoides subsp. mycoides large-colony type were 99.9% identical. We therefore suggest that these species be reclassified in a common species group (for instance, "Mycoplasma capri") distinct from the M. mycoides subsp. mycoides small-colony type, which formed an intermediate branch between the M. capricolum species group and the M. capri species group.

Contagious bovine pleuropneumonia in northern Tanzania, culture confirmation and serological studies

After an absence of about 25 years contagious bovine pleuropneumonia (CBPP) appeared again in 1990 in Tanzania. It was preceded by a spread in Kenya to an area bordering Tanzania. Due to the frequent cattle movements across the border it was soon introduced into Loliondo in northern Tanzania. One month after the first cases, CBPP was suspected in a total of 9 herds comprising 1,500 cattle. However, few animals showed clear clinical signs and frequent antibiotic treatment at an early stage further obscured the clinical picture. In one herd with acute cases, the diagnosis was confirmed by autopsy and Mycoplasma mycoides subsp. mycoides, SC type, was isolated. From this herd several serum samples were positive in the complement fixation test and gave high absorbance values in an ELISA with M. mycoides subsp. mycoides antigen. From 5 other herds with suspected cases blood samples were negative by the complement fixation test but in the enzyme-linked immunosorbent assay at least one in each herd was positive.

Application of dot immunobinding on membrane filtration (MF dot) to the study of relationships within "M. mycoides cluster" and within "glucose and arginine-negative cluster" of ruminant mycoplasmas

A total of 189 isolates from cattle, sheep and goats, allocated to two groups on biochemical grounds, have been examined by a dot immunobinding membrane-filtration (MF dot) method. Seventy glucose fermenting isolates, showing relationships with the "Mycoplasma mycoides cluster", have been compared by MF dot against polyclonal hyperimmunesera prepared against the following reference strains: M. mycoides subsp. mycoides, small colony type (SC), strain PG1 and large colony type (LC) strain Y Goat; M. capricolum strain California Kid (CK); M. species bovine serogroup 7 strain PG50, and, ovine/caprine serogroup 11 strain 2-D. The isolates fell into 5 main groups: (a) 14 serologically homogeneous isolates similar to subsp. mycoides SC PG1 (b) 4 homogeneous isolates similar to PG50 (c) 14 isolates all serologically similar to Y Goat, but heterogeneously reactive with subsp. capri PG3 and M. capricolum CK antisera (d) 7 isolates serologically similar to subsp. capri PG3, but heterogeneously reactive with subsp. mycoides SC PG1, M. capricolum CK and 2-D antisera (e) 28 isolates strongly reactive with both M. capricolum CK and serogroup 7 PG50 antisera. 119 isolates that were all glucose and arginine negative were also compared by the MF dot method with the reference strains. Most of these could be classified definitely as M. bovis (78 isolates), M. agalactiae (21 isolates) and serogroup 11 (5 isolates). 13 isolates gave a strong reaction with both M. bovigenitalium and serogroup p11 antisera. 2 isolates showed an unclassifiable pattern. The results confirm that the glucose and arginine-negative cluster strains that reacted with 2-D antiserum, also share serological relationships with the "M. mycoides cluster", albeit with a very heterogeneous pattern.

Application of a diagnostic DNA probe for the differentiation of the two types of Mycoplasma mycoides subspecies mycoides

Contagious bovine pleuropneumonia (CBPP), which is caused by Mycoplasma mycoides subspecies mycoides, is still a serious disease in some parts of the world. There is also a commonly occurring mycoplasma which is sufficiently related to the CBPP organism to bear the same name, even though this organism does not cause CBPP. Thus it is very important to be able to distinguish between these organisms and identify either with certainty. Fragments derived from M mycoides subspecies capri by restriction enzyme digestion of genomic DNA were cloned into the vector M13mp8. One resulting clone CAP-21, with a 1.5 kb insert was used as a probe in Southern hybridisation assays where genomic DNA was digested with the restriction endonuclease TaqI. This probe could differentiate a strain of M mycoides subspecies mycoides which does not cause CBPP. Subsequent tests on 14 other strains from cattle and goats showed that although they were isolated from diverse geographical areas, CAP-21 could clearly differentiate between these two types of M mycoides subspecies mycoides.

Mycoplasma ovipneumoniae infection in Zimbabwean goats and sheep

The prevalence of Mycoplasma ovipneumoniae (MO) in three Communal Lands flocks of goats on the outskirts of Harare is described. In a single sampling of nasal swabs from 172 randomly selected, apparently healthy goats, 112 animals were identified as carriers of MO. The three flocks had a history of occasional deaths, following chronic and subacute pneumonia associated with isolation of MO as the only identifiable pathogen. Attempts to induce clinical pneumonia in groups of 6 to 8-week-old kids and lambs with local isolates of MO were not successful. However, MO was consistently cultured from the trachea, lungs, lymph node and thymus of some test animals. Cuffing interstitial pneumonia was also observed in these animals. Infection of the thymus occurred; this has not previously been reported with any Mycoplasma sp. The animals did not produce detectable serum antibodies to MO nor were they reactive to MO antigen in a tuberculin-type hypersensitivity test. The possibility that a state of immunotolerance may have been responsible for failure to develop clinical pneumonia is discussed.

Identification of ruminant mycoplasmas by dot immunobinding on membrane filtration (MF dot)

A simple method of species identification of ruminant mycoplasmas by dot immunobinding (MF dot) is described. Mycoplasmas from broth cultures were directly trapped onto the surface of low protein-binding affinity membranes by vacuum filtration. Specific polyclonal anti-mycoplasma sera were then applied. Mycoplasma-antibody complexes were then revealed by an enzyme conjugated anti-immunoglobulin. A positive reaction was indicated by the development of a color reaction when substrate was added. The method was tested on 22 type-strains representative of species, subspecies, types or yet unnamed serogroups of mycoplasmas isolated from ruminants. MF dot presented a specificity close to that which could be expected from the reference serological tests. The advantages of the MF dot over the other tests are utility, rapidity, ready standardization and it allows many samples to be treated simultaneously.

Detection of antibodies to mycoplasmas in South American camelids

Indirect haemagglutination tests on sera from 757 South American camelids (alpacas, llamas and vicunas) carried out in the Andean region of Peru, revealed evidence of exposure mainly to Mycoplasma mycoides subspecies mycoides LC. The incidence of detectable antibodies to this mycoplasma in 554 alpacas was 5.0 per cent and in 141 llamas 15.6 per cent. Antibody to Mycoplasma capricolum and the F38 biotype was detected in 0.9 per cent and 0.2 per cent of alpacas, respectively. In a group of 62 vicunas only one reactor to both M m mycoides LC and M capricolum was observed. No reactors to M mycoides subspecies capri or M agalactiae were observed in the flocks examined. Antibodies to mycoplasma were also detected in nine out of 10 goat flocks tested. The incidence of antibodies to M m mycoides LC was 13.8 per cent, 3.8 per cent for M capricolum and 1.8 per cent for the F38 biotype. In a group of 110 sheep, six reactors (5.5 per cent) to M m mycoides LC and one (0.9 per cent) to F38 were observed. The implications of these results are discussed in relation to the involvement of mycoplasmas in existing disease in camelids in Peru.

Cytotoxicity of Mycoplasma mycoides subspecies mycoides for cultured endothelial cells

Toxic effect of 5 SC- and 4 LC-type strains of Mycoplasma mycoides subspecies mycoides has been demonstrated in cultured endothelial cells. The SC strains are agents of contagious bovine pleuropneumonia and presumably specific for cattle although occasionally isolated from goats. The LC strains produce an acute septicemic disease in goats and a few strains have been reported in cattle. The tissue culture cytotoxic dose causing 75% cell death (TCCD75) was calculated for each strain. Cytotoxicity ranged from 0.9 X 10(9) to 12.0 X 10(9) when strains were tested in bovine endothelial cells with the SC strains being twice as cytotoxic as the LC strains on average. Strains G175/78 and D44 representing the most cytotoxic SC and LC strains respectively, were selected for comparative experiments using bovine, caprine and porcine endothelial cells, bovine embryonic lung fibroblast cells (BELF) and the bovine cell line Madin-Darby kidney cells (MDBK). Strain G175/78 was significantly more cytotoxic for bovine endothelial cells than caprine and porcine, suggesting that the cytotoxicity reflects specificity for the bovine species. This strain was also cytotoxic for BELF but not for MDBK cells indicating that not all bovine cells are susceptible. Conversely, cytotoxicity of strain D44 was not significantly different in any of the endothelial cells tested, although cytotoxicity for BELF was significantly different, the cytotoxicity of the LC strains seems to be of less specificity.

Adherence of Mycoplasma mycoides subspecies mycoides to cultured endothelial cells

The LC- and SC-type strains of Mycoplasma mycoides subspecies mycoides were examined for adherence to guinea pig erythrocytes and bovine and caprine endothelial cells. The LC-type strains but not the SC-type strains adsorbed guinea pig erythrocytes and caprine endothelial cells. Difference in cytoadherence was observed between strains of the LC-type. The interaction between the most adherent LC-type strain and caprine endothelial cells was examined by transmission and scanning electron microscopy.

Growth characteristics of large- and small-colony types of Mycoplasma mycoides subsp. mycoides on 5% sheep blood agar

Mycoplasma mycoides subsp. mycoides of the large-colony (LC) type was isolated in pure culture on 5% sheep blood agar plates inoculated with lung specimens from a 4-month-old Toggenburg goat. The growth characteristics of this isolate, of four known LC types, and of five known small-colony (SC) types of M. mycoides subsp. mycoides were compared on 5% sheep blood agar at 2, 5, and 7 days. The SC types were not visible at 2 days and did not grow larger than 0.1 mm, whereas the LC types were visible in 2 days and increased in diameter over 7 days to between 0.4 and 0.7 mm. These results indicate that growth on 5% sheep blood agar can be used as an additional marker in differentiating LC and SC types of M. mycoides subsp. mycoides.

Immunogenic variation among the so-called LC strains of Mycoplasma mycoides subspecies mycoides

Much evidence of immunogenic heterogeneity among the LC strains of Mycoplasma mycoides ssp. mycoides emerged from cross-immunization and -hyper-immunization experiments in mice in which three LC strains (Vom/Plum Island, 74/2488, and Mankefår 2833) were used for challenge purposes. All heterologous LC-strain vaccines cross-immunized against the three challenge strains, but protection was usually only 'partial', i.e. significantly less than that given by homologous vaccine. Cross-hyperimmunization with all heterologous LC but not SC strains produced protection against challenge with Vom/Plum Island that was virtually 'complete', i.e. similar to that produced by homologous vaccine. Challenge with 74/2488 gave generally similar results; but against Mankefår 2833 six heterologous LC vaccines gave complete protection and six did not. Vaccines prepared from the Smith (1423) strain of M. mycoides ssp. capri gave some protection against Vom/Plum Island but none against 74/2488 or Mankefår 2833. The cross-immunizing ability of three further M. mycoides ssp. capri strains appeared to resemble that of Smith (1423). In a cross-hyperimmunization experiment, vaccines prepared from SC strains of M. mycoides ssp. mycoides varied greatly in their ability to protect against challenge with strains 74/2488 and Mankefår 2833.

Some in-vitro characters of the subspecies of Mycoplasma mycoides

So-called LC strains of Mycoplasma mycoides subsp. mycoides and, where appropriate, SC strains, were examined, together with M. mycoides subsp. capri strains, by growth, fermentation, and antibiotic-sensitivity tests. Growth curves in BVF-OS medium showed that, from the 6th until at least the 19th day of incubation, strain Mankefår 2833 had a viable count strikingly higher than that of any other LC strain. Its robust growth properties may explain its ability--unusual among LC strains--to produce mycoplasmaemia readily in mice. Strain 143-A66 Conn, also shown by earlier experiments in mice to possess unusual properties, lost viability more rapidly than any other LC strain between the 13th and 19th days of incubation. The viable count of a subsp. capri strain was considerably lower than that of any LC strain for much of the period between days 6 and 19. In fermentation tests with 27 substrates and sensitivity tests with 11 antibiotics the strains gave results that, in all but the following respects, were uniform. Sorbitol was fermented to varying degrees by all the LC and subsp. capri strains tested but was unaffected by the SC strains. The LC and subsp. capri strains were in general more resistant than the SC strains to streptomycin. The growth of the LC strains, much more than that of the other strains, was greatly stimulated by the presence of fermentable substrate.

Mycoplasma mycoides subsp mycoides, LC type, from goats in Italy

A mycoplasma identified as Mycoplasma mycoides subsp mycoides LC type was isolated from an outbreak of caprine pleuropneumonia and serofibrinous peritonitis. This isolate was the first to be reported in Italy. Experimentally, a rapidly fatal condition followed its inoculation into goats and sheep but inoculation of calves did not lead to clinically apparent infection. Although the organism was recovered for up to 45 days following experimental inoculation of calves, pathological changes were limited to the drainage lymph nodes except in one case where there were histological changes in the lungs.

Observations on the antigenic differences between the so-called SC and LC strains of Mycoplasma mycoides subsp. mycoides

The so-called SC (small colony) and LC (large colony) strains of Mycoplasma mycoides subsp. mycoides are said to be indistinguishable by the in vitro serological tests of generally used in mycoplasmology. In mice the immunity given by a single dose of killed LC-strain vaccine against challenge with SC strains is - unlike that given by SC-strain vaccine - only partial. When multiple doses of killed or living vaccines were given, the majority of 13 LC strains still failed to immunize completely against a SC strain. This suggests that, although some protective antigens are shared between both types of strain, at least one of importance is present in the SC strains but absent from the majority of LC strains. The difference between the protective-antigen content of SC and most LC strains is thus qualitative, and not merely quantitative.

The ability of Mycoplasma mycoides subspecies mycoides and closely related strains from goats and sheep to immunize mice against subspecies capri

Small colony (SC) strains of Mycoplasma mycoides subsp. mycoides from contagious bovine pleuropneumonia (CBPP) and from goats were compared with large colony (LC) strains of so-called M. mycoides subsp. mycoides from goats and sheep by means of a cross-protection test in which mice were challenged with M. mycoides subsp. capri. Of 13 LC strains, all gave partial cross-protection, and 11 were shown to be more closely related than four SC strains to subspecies capri. In a further experiment, six SC strains--three from CBPP and three from goats--all gave weak partial cross-protection against subspecies capri.

The relationship of two equine mycoplasmas to Mycoplasma mycoides

Two unidentified mycoplasmas, N3 and N11, isolated from the respiratory tract of horses, were found to cross-react with strains of M. mycoides subsp. mycoides in indirect immunofluorescence tests, growth-inhibition tests carried out by the running drop/agar-well method, and in complement-fixation and double immunodiffusion tests. Serologically, the equine mycoplasmas were not completely identical with any of the reference strains of M. mycoides with which they were compared. Their cultural characteristics, ability to digest coagulated serum and casein, and survival at 45 degrees C, however, suggested that they were more closely related to strains of M. mycoides subsp. mycoides, such as Y-goat, which are found in goats, than to strains of that subspecies which are pathogenic for cattle.

Further studies on caprine and ovine mycoplasmas related to Mycoplasma mycoides subsp. mycoides

Nine caprine and ovine mycoplasma strains, said to be indistinguishable serologically from Mycoplasma mycoides subsp. mycoides (the causative organism of contagious bovine pleuropneumonia; CBPP) were examined in mice by (1) a mycoplasmaemia test, and (2) a cross-protection test. Of the nine strains, two from goats belonged to a small colony (SC) type; four caprine and three ovine strains belonged to a large colony (LC) type.The two SC strains - like a single SC strain examined in an earlier study - were indistinguishable from genuine M. mycoides subsp. mycoides as isolated from CBPP. They produced mycoplasmaemia readily. In a cross-protection test, the two SC strains and a CBPP strain immunized completely against each other.Of the seven LC strains, six - like six LC strains examined in an earlier study - were easily distinguished from genuine M. mycoides subsp. mycoides; except for one that was not tested, all were shown to lack the ability to produce mycoplasmaemia readily. In cross-protection tests all six strains immunized partially but not completely against a CBPP strain.The seventh LC strain (Mankefår 2833) was exceptional: it produced mycoplasmaemia readily, resembling the SC strains in this respect. Like other LC strains, in cross-protection tests it protected only partially against a CBPP strain. Strain Mankefår 2833 was isolated in ca. 1965 by Brack from a Barbary sheep (Ammotragus lervia) in a German zoo.The ability of Mankefår 2833 to produce mycoplasmaemia enabled it to be used as a challenge strain in cross-protection tests. For the purpose of such tests the collection of nine mycoplasma strains referred to above was augmented with six LC strains from an earlier study. Partial but not complete protection against Mankefår 2833 was produced by two caprine SC strains, one CBPP strain, and nine LC strains. Three further LC strains gave protection that may have been as strong as that produced by the homologous strain, but confirmatory experiments are needed. A strain of M. mycoides subsp. capri gave no protection against Mankefår 2833.