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.     

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.     

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.     

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.     

Indirect infection of cattle with contagious bovine pleuropneumonia.

Hay infected with Mycoplasma mycoides sub-species mycoides (M mycoides) was fed to six animals on three occasions. Five animals developed complement-fixing antibody in their sera and gave a positive reaction to the comparative intradermal allergic test. No animal died from contagious bovine pleuropneumonia (CBPP) but when they were killed, three had unequivocal lesions of the disease. M mycoides was isolated from the animals with these lesions but not from the others. CBPP was transmitted to two animals put in contact with those animals showing disease, and M mycoides was recovered from lesions in both animals. It is suggested that when unexplained outbreaks of CBPP occur, the possibility of indirect transmission should be considered.     

Development of real-time diagnostic assays specific for Mycoplasma mycoides subspecies mycoides Small Colony

Rapid and specific detection of Mycoplasma mycoides subsp. mycoides Small Colony (M. mycoides SC) is important for the effective control of contagious bovine pleuropneumonia. Although the United States has been free of this disease for over 100 years, it is necessary to develop modern diagnostic assays that are sensitive and specific for biological agents that would affect the US agricultural industry following accidental or intentional introduction into the US agricultural population. With this aim in mind, we have identified M. mycoides SC-specific genetic loci and developed TaqMan-based PCR assays for the detection of M. mycoides SC. The TaqMan assay allows for real-time detection of specific, amplified PCR products using portable equipment, enabling testing to be performed in the field. These assays are specific for M. mycoides SC, failing to amplify DNA from other organisms belonging to the M. mycoides cluster or two phylogenetically unrelated bovine mycoplasma species. Standard curves were drawn based on the linear relationships measured between the threshold fluorescence (C(T)) values and a measured quantity of genomic DNA. M. mycoides SC was successfully detected in bronchoalveolar lavage samples obtained from experimentally infected cattle. These TaqMan-based real-time PCR assays will allow for the rapid and specific detection of M. mycoides SC.     

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.     

Susceptibility of goats and calves after experimental inoculation or contact exposure to a Canadian strain of Mycoplasma mycoides subsp. mycoides isolated from a goat.

Transmissibility of Mycoplasma mycoides subsp. mycoides infection from experimentally inoculated goats to other goats and calves was studied. Eight goats and six calves were housed in an 18 m2 room. Six of the goats were inoculated endobronchially with strain D44 isolated from a natural case of polyarthritis in Ontario. These six goats died within a week of Mycoplasma septicemia. The two contact goats or the six calves never showed signs of disease and M. mycoides subsp. mycoides was not recovered from these animals. The contact goats and four calves were killed 25 days after exposure. They were all seronegative, M. mycoides subsp. mycoides was not recovered at necropsy and none had pathomorphological changes attributable to this Mycoplasma. The two remaining calves were inoculated endobronchially with 10(9) CFU of strain D44 and observed for 20 days. They never showed signs of disease and did not have significant lesions at necropsy. Both developed a significant serological response to M. mycoides subsp. mycoides, although this organism was not recovered during the experimental period or at necropsy. This study did not provide evidence for transmission of M. mycoides subsp. mycoides from endobronchially inoculated goats to contact goats or calves and endobronchially inoculated calves did not develop pneumonia. This would suggest that the infection of the goat population in Canada with this pathogen would not be a significant threat to the cattle population.     

A reassessment of the dual vaccine against rinderpest and contagious bovine pleuropneumonia

In the light of the recent outbreaks of rinderpest in Africa a further assessment of the efficacy of the simultaneous inoculation of rinderpest virus vaccine and contagious bovine pleuropneumonia vaccine was undertaken. Groups of cattle were inoculated with a dual preparation of rinderpest vaccine virus and Mycoplasma mycoides subspecies mycoides or M mycoides alone. These groups were then challenged with M mycoides, first unsuccessfully by an in-contact challenge method and then by subcutaneous challenge. All animals were examined clinically after challenge for evidence of contagious bovine pleuropneumonia and serologically for rinderpest virus and M mycoides mycoides antibodies. There was no evidence that the serological response to the dual vaccine was in any way less than that to either agent given alone and no clinical disease was detected in these animals after in-contact challenge. However, after subcutaneous challenge, the dual vaccinated groups reacted similarly to an unvaccinated control group and unlike the group vaccinated only with M mycoides. This would indicate that the rinderpest virus component of the dual vaccine interfered with the ability of the M mycoides component to induce a fully effective immune response. In the pan African rinderpest campaign the use of the dual vaccine in areas where contagious bovine pleuropneumonia occurs should be carefully considered; in areas where the disease does not occur it is contraindicated.     

牛支原体、无乳支原体和丝状支原体丝状亚种小克隆三重PCR检测方法的建立及初步应用

本研究旨在建立一种可一次性区分牛支原体、丝状支原体丝状亚种小克隆和无乳支原体的三重PCR诊断方法,为临床诊断和流行病学调查提供可靠检测技术.根据GenBank发表的上述3种病原的基因组序列保守区域设计3对特异性引物建立三重PCR方法;确定其检测敏感性,以猪支原体、鸡支原体、无乳支原体和丝状支原体丝状亚种小克隆基因作模板检验其特异性;同时和病原分离鉴定结果对比其准确性.结果表明在优化体系和条件下能够同时得到扩增长度为448、549、375 bp 3条特异性片段,未扩增出猪、鸡支原体模板特异性片段;其敏感性(可检测到的最小模板DNA含量)为0.8 ng·μL-1;36份临床样品检测结果显示,三重PCR检测结果与分离培养鉴定方法一致,均能鉴定出牛支原体阳性病料.本研究建立的三重PCR诊断方法能够一次性鉴别3种支原体,具有高敏感性、特异性和准确性,可用于临床诊断和流行病学调查.     

丝状支原体簇和多杀性巴氏杆菌双重PCR方法的建立及应用

本研究旨在建立丝状支原体簇和多杀性巴氏杆菌的双重PCR检测方法,从而为临床上同时检测这2类病原的感染提供一种更方便、快捷、准确的工具。本研究采用2对特异性检测丝状支原体簇和多杀性巴氏杆菌的引物,对PCR反应体系和反应条件进行了优化,并对双重PCR的特异性及敏感性进行了评价,随后采用该方法对52份临床样本进行了检测。结果显示,所建立的双重PCR方法能同时扩增丝状支原体簇成员和多杀性巴氏杆菌的DNA,而对来源于其他常见病原的DNA均无扩增;对丝状支原体簇和多杀性巴氏杆菌的最低检测限分别为24.8和28.9 pg;能成功地从临床样本中检测丝状支原体簇成员和多杀性巴氏杆菌。结果表明,本研究所建立的双重PCR方法具有很好的特异性和敏感性,为临床丝状支原体簇和多杀性巴氏杆菌感染的快速诊断、病原鉴定及流行病学调查提供了有效的方法。     

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.     

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.     

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.     

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.     

The serological reactions of Mycoplasma isolated from pneumonic sheep lungs in the Sudan.

Seven mycoplasma isolated from pneumonic sheep lungs were found to belong to two serologically unrelated groups. Isolates in one group reacted strongly with antisera to M arginini in the metabolic inhibition and growth inhibition tests. All isolates except one failed to react with antisera to M mycoides var capri or M mycoides var mycoides. The results of the present work support the previously reported division of the isolates into two groups on the basis of their biological properties.     

SUBDIVISION OF MYCOPLASMA MYCOIDES SUBSP. MYCOIDES FROM CATTLE AND GOATS INTO TWO TYPES

Some strains of Mycoplasma mycoides subsp. mycoides, mostly isolated from goats, grow to greater turbidity in broth and form larger colonies on solid medium than does the type strain, PG1. These strains also digest casein, liquefy inspissated serum actively and survive longer at 45 degrees C and are referred to as LC (large colony) strains. Strains more closely resembling PG1 have been called SC (small colony) strains. The SC strains comprise those from contagious bovine pleuropneumonia (CBPP) and some from goats. One LC strain was isolated from a steer; all others have come from goats. Differentiation of M. mycoides subsp. mycoides into 2 types on the basis of the characteristics described may be relevant to their role in CBPP.     

羊丝状支原体簇环介导等温扩增检测方法的建立

本试验利用环介导等温扩增技术(LAMP)建立了羊丝状支原体簇的快速检测方法,该方法以羊丝状支原体簇成员的保守性基因16S rRNA为靶序列,设计了4条特异性引物,在65 ℃等温条件下,60 min一步完成反应。在反应管中预先添加羟基萘酚蓝(HNB),阳性呈蓝色,阴性呈紫色。丝状支原体簇成员——丝状支原体山羊亚种(Mmc)、丝状支原体丝状亚种LC型(Mmm LC)、山羊支原体山羊肺炎亚种(Mccp)的LAMP检测为阳性;对其他病原菌没有交叉反应。以Mmc的核酸为模板进行灵敏度检测,LAMP的最低检出限为10 pg/μL。结果表明,本试验建立了一种特异、敏感、快速、简便的羊丝状支原体簇的LAMP方法。     

The identification of an organism isolated from maned sheep as Mycoplasma mycoides subsp. mycoides

The natural host-range of M. mycoides subsp. mycoides is generally believed to be restricted to cattle, although the production in experimental conditions of a generalized infection of sheep and goats has been reported on some occasions.