A specific PCR for the identification of Mycoplasma capricolum subsp. capripneumoniae, the causative agent of contagious caprine pleuropneumonia (CCPP)

Contagious caprine pleuropneumonia is a severe infectious disease of goats in Africa and the Middle East. It is caused by a fastidious mycoplasma, Mycoplasma capricolum subsp. capripneumoniae, a member of the "M. mycoides cluster". Members of this cluster share genomic and antigenic features, which result in common biochemical and serological properties, complicating species identification. Two species of this cluster, M. mycoides subsp. capri and M. mycoides subsp. mycoides large colony biotype, are very often isolated from clinical cases resembling contagious caprine pleuropneumonia. Furthermore, in the laboratory, M. capricolum subsp. capripneumoniae can be easily confused with the closely related capricolum subspecies. Considering these constraints and the scarcity of available methods for identification, a specific polymerase chain reaction was developed. A DNA fragment of 7109 bp containing genes coding for the arginine deiminase pathway (ADI) was chosen as target sequence for the selection of a specific primer pair. The full ADI operon from M. capricolum subsp. capripneumoniae strain GL100 was sequenced. Polymorphism within this locus was analyzed by comparison with the sequence from the closely related IPX strain (M. capricolum subsp. capricolum). It varied from 0.6% to 3.5%. The highest divergence was found in a region coding for arcD. Therefore, this gene was chosen as target for the specific amplification of a 316 bp-long DNA fragment. The specificity of this PCR was validated on 14 M. capricolum subsp. capripneumoniae strains and 27 heterologous strains belonging to the "M. mycoides cluster" and M. putrefaciens. This new PCR will be a valuable tool for the surveillance of contagious caprine pleuropneumonia.     

Phylogeny of the Mycoplasma mycoides cluster as shown by sequencing of a putative membrane protein gene

The Mycoplasma mycoides cluster is made of six species that are closely related both genetically and phenotypically. Two are of particular importance, M. mycoides subsp. mycoides SC causing contagious bovine pleuropneumonia and M. capricolum subsp. capripneumoniae causing contagious caprine pleuropneumonia. The sequences of a putative membrane protein gene and partial flanking open reading frames have been obtained from various strains in this cluster, including all reference strains. Sequence analysis showed this locus is present and fully conserved in all strains of M. mycoides subsp. mycoides SC isolated from geographically most distant places worldwide. In M. capricolum subsp. capripneumoniae polymorphism in this locus has been found at seven positions and revealed that they can be used as epidemiological markers. Conserved regions were used to define a primer pair that enables the amplification by PCR of two fragments 302 and 1298bp long, respectively. The 302bp long fragment contains an intergenic sequence that can be used for phylogenetic studies or for identification purposes. Parsimony analysis on an alignment of 49 DNA sequences show a subdivision of the M. mycoides cluster into two subgroups that is in accordance with results obtained by phenotypic methods. Two lineages exist within the capricolum subgroup, one of them clustering strains identified as M. capricolum subsp. capricolum, M. capricolum subsp. capricolum and M. sp Bovine Group 7. However M. capricolum subsp. capripneumoniae strains can readily be identified by three specific nucleotide positions or by sequencing the 1298bp long fragment. There is no clear subdivision within the mycoides subgroup, supporting the idea that M. mycoides subsp. mycoides LC and M. mycoides subsp. capri should not be separated into two subspecies. Mycoplasma mycoides subsp. mycoides SC strains can easily be distinguished as they bear an insertion sequence 15bp downstream from the stop codon of the membrane protein gene.     

Genetic diversity and evolution of Mycoplasma capricolum subsp. capripneumoniae strains from eastern Africa assessed by 16S rDNA sequence analysis

Mycoplasma capricolum subsp. capripneumoniae (M. capripneumoniae), the causal agent of contagious caprine pleuropneumonia (CCPP), is a member of the so-called Mycoplasma mycoides cluster. These mycoplasmas have two rRNA operons in which intraspecific variations have been demonstrated. The sequences of the 16S rRNA genes of both operons from 13 field strains of M. capripneumoniae from three neighbouring African countries (Kenya, Ethiopia, and Tanzania) were determined. Four new and unique polymorphism patterns reflecting the intraspecific variations were found. Two of these patterns included length differences between the rrnA and rrnB operons. The length difference in one of the patterns was caused by a two-nucleotide insert (TG) in the rrnB operon and the length difference in the other pattern was due to a three-nucleotide deletion, also in the rrnB operon. Another pattern was characterised by a polymorphic position caused by a mutation that is known to cause streptomycin resistance in other bacterial species. The strain with this pattern was also found to be resistant to streptomycin. Streptomycin resistant clones were selected from four M. capripneumoniae strains to further investigate the correlation of this mutation to streptomycin resistance. Mutations in the 16S rRNA genes had occurred in two of these strains. The fourth pattern included a new polymorphism in position 1059. The results show that polymorphisms in M. capripneumoniae strains can be used as epidemiological markers for CCPP in smaller geographical areas and to study the molecular evolution of this species.     

The in vitro effect of six antimicrobials against Mycoplasma putrefaciens, Mycoplasma mycoides subsp. mycoides LC and Mycoplasma capricolum subsp. capricolum isolated from sheep and goats in jordan

Respiratory disease in sheep and goats is a major problem in Jordan and is often associated with Mycoplasma species. Without effective vaccines, control is mainly by chemotherapy, but the uncontrolled use of antimicrobials has led to concerns about the potential development of antimicrobial resistance. The in vitro effect of chloramphenicol, florfenicol, enrofloxacin, tylosin, erythromycin and oxytetracycline was determined against 32 isolates of Mycoplasma species-M. mycoides subsp. mycoides LC (6), M. capricolum subsp. capricolum (8) and M. putrefaciens (18), all isolated from either nasal swabs or milk, from sheep and goats in different regions of Jordan. The antimicrobial susceptibility showed some Mycoplasma species-specific differences, with M. capricolum subsp. capricolum being more susceptible to tylosin and erythromycin. Chloramphenicol and florfenicol were the least effective for all three Mycoplasma species. No trends or significant differences in antimicrobial susceptibilities were observed between sheep and goat isolates, between milk or nasal swab isolates, or between isolates from different regions of Jordan. Some isolates of M. capricolum subsp. capricolum and M. putrefaciens showed higher MIC levels with oxytetracycline, as did two isolates of M. mycoides subsp. mycoides LC with tylosin, possibly indicating signs of development of antimicrobial resistance.     

Mycoplasma mycoides subsp. capri and Mycoplasma mycoides subsp. mycoides LC can be grouped into a single subspecies

Mycoplasma mycoides subsp. capri and Mycoplasma mycoides subsp. mycoides LC can be combined into one taxon on the basis of several contributions on both DNA sequence and protein analyses reported in the literature. Moreover, for the differentiation and identification of mycoplasmas of the "mycoides cluster", we investigated the rpoB gene, encoding the beta-subunit of the RNA polymerase. A segment of 527 bp of the rpoB gene was amplified from 31 strains of ruminant mycoplasmas by PCR. The nucleotide sequences were determined and aligned, and accurate genetic relationships were calculated. Cluster analysis of rpoB DNA allowed species differentiation within the "mycoides cluster" and confirmed that M. mycoides subsp. capri and M. mycoides subsp. mycoides LC cannot be distinguished from each other. "Mycoplasma mycoides subsp. capri" is proposed as a common name for both subspecies.     

Real-time polymerase chain reaction assays for the detection of members of the Mycoplasma mycoides cluster

AIM: To develop real-time PCR assays for the detection and differentiation of members of the Mycoplasma mycoides cluster. METHODS: Five real-time PCR assays were designed to allow differentiation of members of the M. mycoides cluster: an assay for detection of the M. mycoides subspecies, viz M. mycoides subsp mycoides large colony (MmmLC), M. mycoides subsp capri (Mmc), and M. mycoides subsp mycoides small colony (MmmSC); one for the detection of the M. capricolum subspecies, viz M. capricolum subsp capricolum (Mcc), M. capricolum subsp capripneumoniae (Mccp), and Mycoplasma sp bovine group 7 (BG7); and three for the specific detection of MmmSC, Mccp, and BG7. A panel of 74 Mycoplasma isolates from various geographical origins and a panel of 21 other bacterial isolates were used to evaluate the sensitivity and specificity of the assays. RESULTS: The assays displayed 100% analytical sensitivity in detecting all target Mycoplasma isolates. The analytical detection limit for the assays to detect the M. mycoides subspecies, M. capricolum subspecies, and MmmSC was determined to be 100 fg of genomic DNA, while the Mccp and BG7 assays had a detection limit of 100 fg and 10 fg of genomic DNA, respectively. The M. mycoides subspecies assay had a detection limit of 10(3) (SD 10(2)) cfu/ml milk, 10(4) (SD 10(4)) cfu per swab, and 10(3) (SD 10(3)) cfu/g lung in inoculated samples. The assays displayed 100% specificity when applied to non-target bacterial isolates and to 110 culture-negative milk samples. CONCLUSIONS: The assays were highly sensitive and specific, and provide accurate detection and differentiation of the members of the M. mycoides cluster.     

Molecular analysis of field strains of Mycoplasma capricolum subspecies capripneumoniae and Mycoplasma mycoides subspecies mycoides, small colony type isolated from goats in Tanzania.

A molecular analysis of strains of Mycoplasma capricolum subsp. capripneumoniae (M. capripneumoniae) and Mycoplasma mycoides subsp. mycoides, small colony type (M. mycoides SC) isolated from goats was performed using the amplified fragment length polymorphism (AFLP) and pulsed-field gel electrophoresis (PFGE) fingerprinting techniques. Among the 11 field strains of M. capripneumoniae from Tanzanian goats, two AFLP patterns were demonstrated, with 10 of the strains showing indistinguishable patterns. Five Kenyan strains of M. capripneumoniae produced three AFLP patterns, with two of them being indistinguishable from the 10 identical Tanzanian and one Ugandan strain (M74/93) isolated from sheep. The AFLP pattern of the type strain (F38(T)) was identical to two Kenyan strains (Baringo and G183/82). On PFGE analysis, all the examined M. capripneumoniae strains exhibited identical PFGE profiles.Five field strains of M. mycoides SC isolated from goats displayed identical AFLP patterns except for one strain which differed from others at only one position. The AFLP pattern of the type strain of M. mycoides SC (PG1(T)) was different from the field strains. The five field strains of M. mycoides SC produced identical PFGE profiles, which were, however, different from the type strain. The AFLP and PFGE profiles of M. mycoides SC strains from goats were identical to those of six strains isolated from cattle affected with contagious bovine pleuropneumonia (CBPP) in the same areas. The results of this study suggest a close epidemiological linkage between strains of M. capripneumoniae and between M. mycoides SC type, respectively, isolated from goats in Tanzania.     

Mycoplasma mycoides subsp. capri associated with goat respiratory disease and high flock mortality

A high mortality outbreak of respiratory mycoplasmosis occurred in goats in Mexico. The clinicopathologic presentation resembled contagious caprine pleuropneumonia caused by Mycoplasma capricolum subspecies capripneumoniae. By using a battery of polymerase chain reaction assays, the mycoplasma associated with this outbreak was identified as Mycoplasma mycoides subsp. capri.     

山羊支原体山羊肺炎亚种单克隆抗体的制备及抗体结合抗原表位的筛选

本研究旨在制备山羊支原体山羊肺炎亚种(M.capricolum subsp.capripneumoniae, Mccp)的单克隆抗体并筛选与抗体结合的抗原表位。试验用甲醛灭活的Mccp免疫BALB/c小鼠,运用传统的细胞融合技术进行融合获得杂交瘤细胞,亚克隆,制备单克隆抗体腹水,采用酶联免疫技术（ELISA）和免疫印迹（Western blotting）技术鉴定单克隆抗体的特异性及胶内酶切鉴定与抗体结合的抗原表位。最终成功筛选获得5株单克隆抗体,鉴定到3个与抗体结合的抗原表位,为下一步科学研究提供了初步且可靠的试验基础。     

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.     

First isolation of Mycoplasma capricolum subsp. capricolum, one of the causal agents of caprine contagious agalactia, on the island of Lanzarote (Spain)

During an unusually long period of bad weather, several outbreaks of caprine contagious agalactia (CCA) were reported in a number of flocks on the island of Lanzarote (Canary Islands, Spain). Clinical and subclinical mastitis in lactating goats and some cases of arthritis and pneumonia in kids were observed in the affected flocks. Mycoplasma capricolum subsp. capricolum was isolated as the main causal agent of the outbreaks, associated with M. mycoides subsp. mycoides "large colony type" (Mmm LC) in two flocks. This is the first report of an isolation of M. capricolum subsp. capricolum on the island of Lanzarote. The finding is of epidemiological importance and could complicate plans to control the disease. The significance of this mycoplasma species in association with CCA must now be studied in detail.     

山羊支原体山羊肺炎亚种M1601生长曲线与pH值的测定

为了研究山羊支原体山羊肺炎亚种分离株M1601株在Thiaucourt肉汤培养基中的生长及繁殖特性。利用活菌计数方法对其在不同培养阶段的生长滴度及pH值进行了测定,并绘制了生长曲线。结果表明,传代稳定的M1601在Thiaucourt肉汤培养基中培养6～60h为对数生长期．pH值逐渐下降：培养60～72h进入稳定期．pH值降为6．27．培养72h进入衰亡期。这为山羊支原体山羊肺炎亚种培养特性研究和疫苗生产工艺研究提供了参考数据,以便在生产上更合理地应用其生长规律。     

Development of a bead-based multiplex PCR assay for the simultaneous detection of multiple Mycoplasma species

We describe the development and analytical validation of a 7-plex polymerase chain reaction assay coupled to a bead-based liquid suspension array for detection of multiple ruminant Mycoplasma spp. The assay employs a combination of newly designed and previously validated primer-probe sets that target genetic loci specific for Mycoplasma bovis, Mycoplasma mycoides cluster, Mycoplasma mycoides subsp. mycoides SC (MmmSC) and Mycoplasma capricolum subspecies capripneumoniae (Mccp). Analytical sensitivity for the targeted Mycoplasma species ranged from 10 fg to 1 pg of purified gDNA extracted from broth cultures (approximately 8-800 MmmSC genome equivalents). In silico comparison of primers and probes, and analytical assessment with a range of near-neighbor Mycoplasma species and multiple bacterial respiratory pathogens demonstrated 100% analytical specificity of the assay. To assess assay performance and diagnostic specificity, 192 bovine respiratory samples were analyzed by incorporating a high throughput DNA extraction platform. The assay correctly classified all samples as negative for MmmSC or Mccp. All 33 field samples confirmed as positive for M. bovis by sequencing the uvrC gene were positive in the assay. The results from this study indicate that the bead-based liquid suspension array will provide a reliable, analytically sensitive and specific platform to simultaneously interrogate ruminant respiratory samples for multiple Mycoplasma species, including M. mycoides cluster organisms that are exotic to the United States. Sequential addition of primer-probe sets to the assay did not significantly impact analytical sensitivity of individual primer-probe combinations, suggesting that expanding the assay to include more Mycoplasma species will not compromise overall performance.     

山羊支原体山羊肺炎亚种培养基的筛选及生长曲线测定

为筛选出山羊支原体山羊肺炎亚种的适宜培养基,将山羊支原体山羊肺炎亚种分离株M1601分别接种Thiaucourt肉汤、MEM-KM2和TSA 3种不同的培养基,测定其在3种不同培养基中生长滴度、生长速度,并测定了M1601在最适培养基中在不同培养阶段的生长滴度。结果表明,添加2g/L丙酮酸钠和150mL/L马血清的Thiaucourt肉汤培养基最适宜山羊支原体山羊肺炎亚种的生长,生长滴度可达109 CCU/mL,在培养6h后开始进入对数生长期,培养60h后进入稳定期,培养72h时后进入衰亡期。此试验结果为山羊支原体山羊肺炎亚种培养特性研究提供了参考数据。     

Mycoplasma mycoides subsp. mycoides SC identification by PCR in sperm of seminal vesiculitis-affected bulls.

In this study, by using the polymerase chain reaction (PCR) diagnosis for the detection and identification of Mycoplasma, we investigated mycoplasmas contaminating the semen of yearling bulls affected by seminal vesiculitis. The bulls presented neither subclinical nor clinical contagious bovine pleuropneumonia signs and the complement fixation test for specific antibodies was negative. Furthermore, we have investigated mycoplasmas isolated from semen of healthy breeding bulls of several breeds and origins, which routinely underwent breeding soundness examinations and presented no clinical signs of seminal vesiculitis. We were able to demonstrate mycoplasma infection in all tested samples by i) growth on mycoplasma-specific media and ii) a PCR-based method using a mycoplasma-specific MGSO/GPO1 primer set to amplify the 16S fragment rDNA. In addition, the identification of Mycoplasma species was made by PCR using the MSC1/MSC2 primer set that specifically amplifies M. mycoides subsp. mycoides SC or the MM450/MM451 primer set followed by AsnI digestion analysis in order to identify M. mycoides subsp. mycoides LC. The data presented herein clearly show that M. mycoides subsp. mycoides SC infection was associated with seminal vesiculitis while M. mycoides subsp. mycoides LC was only found in bull semen from healthy control animals. Our findings confirm that the M. mycoides subsp. mycoides SC is shed in the sperm making the ejaculate a valuable biological sample for the isolation of these bacteria from serologically negative animals. Although the pathogenic role of M. bovigenitalium in bull seminal vesiculitis has been established, our clinical findings, semen characteristics, microbiological and bacterial genomic analysis strongly suggest that M. mycoides subsp. mycoides SC may contribute to induce vesicular adenitis in the bull.     

Genetic and antigenic characterisation of elongation factor Tu from Mycoplasma mycoides subsp. mycoides SC

Specific serodiagnosis of contagious bovine pleuropneumonia (CBPP) is hampered by the low antibody titers against Mycoplasma mycoides subsp. mycoides small-colony type (MmmSC) antigens in calf serum due to persistent infections and by the existence of cross-reactions among the members of the mycoides cluster. In order to identify potential diagnostic antigens, we have constructed a genomic library from MmmSC which was screened with antibodies from naturally-infected animals. Using this strategy, a genome fragment has been isolated and characterised. The complete nucleotide sequence of this fragment revealed the presence of several open reading frames, including that of translation elongation factor Tu (EF-Tu), whose product was responsible of the positive reaction observed when expressed in E. coli. The organisation of this MmmSC genome region differed from that of other Mycoplasma species whose complete genome sequences are known, but was similar, by PCR amplification analysis of genomic DNA, to other members of the mycoides cluster, such as Mycoplasma capricolum subsp. capricolum (Mcc). Nevertheless, the MmmSC and Mcc amplicons could be distinguished by digestion with restriction enzymes AseI or HindIII, strategy that could be used as a tool for differential diagnosis of infections caused by members of the mycoides cluster. The full recombinant EF-Tu was produced in E. coli, after correction of an unusual tryptophan codon by site-directed mutagenesis, and used to investigate anti-EF-Tu circulating antibodies in bovine sera.     

Assessment of PCR for routine identification of species of the Mycoplasma mycoides cluster in ruminants

DNA amplification techniques offer considerable promise for the identification of Mycoplasma mycoides cluster members. They avoid antigenic cross-reactivity and variability that hamper serological methods. Many sets of primers, specific of these different members and of Mycoplasma putrefaciens, have been proposed. To assess the reliability of some of these PCR tests in routine laboratory diagnostic use, 230 field strains supposed to belong to this group were simultaneously identified by PCR and an antigenic method. The results were well correlated to antigenic identification for M. putrefaciens, but PCR failed to identify respectively 74% and 52% of M. mycoides subsp. mycoides Large Colony type and M. capricolum subsp. capricolum strains. Any identification of M. mycoides subsp. mycoides Small Colony type must be confirmed by two different tests. Difficulties in defining the M. species bovine serogroup 7 were also encountered with both the PCR and immunological methods. The occurrence of putative variable antigen(s) on the mycoplasma surface may explain part of the identification difficulties encountered with the immunological methods.     

Antigenic and genetic characterisation of lipoprotein lppC from Mycoplasma mycoides subsp. mycoides SC

Lipoprotein lppC, an immunodominant antigen, and its corresponding gene lppC were characterised in Mycoplasma mycoides subspecies mycoides small colony (SC) type, the etiological agent of contagious bovine pleuropneumonia (CBPP). The lppC gene was found in the type strain of M. mycoides subsp. mycoides SC and in field strains isolated in Europe, Africa, and Australia, as well as in vaccine strains. Southern blot analysis indicated the presence of at least four copies of lppC in the genome of M. mycoides subsp. mycoides SC, of which only one seems to be functional. Genes homologous to lppC have also been detected in closely related mycoplasmas such as M. mycoides subsp. mycoides large colony (LC) type and in M. sp. bovine group 7. lppC is encoded as a precursor with a consensus sequence for a prokaryotic signal peptidase II. The amino acid sequence of lppC and its precursor showed similarity to both LppB (at the N-terminal domain) and LppQ (at the C-terminal domain), two lipoproteins described previously in M. mycoides subsp. mycoides SC. The N-terminal domain of the mature lppC seems to be surface exposed. The C-terminal domain presented an integral membrane structure made up of five repeated units, rich in hydrophobic and aromatic amino acids, which may have pore forming potential in the mycoplasmal membrane. A recombinant peptide representing the N-terminal half of lppC was obtained following cloning in vector pETHIS-1 and expression in Escherichia coli hosts. The recombinant protein was used on immunoblots for serological analysis of sera from cattle that were naturally or experimentally infected with M. mycoides subsp. mycoides SC.