Mycoplasma agalactiae and Mycoplasma mycoides group (M. mycoides subsp. mycoides LC biotype; M. mycoides subsp capricolum, M. mycoides subsp. capripneumoniae; M. mycoides subsp. mycoides SC biotype;.... Bovine Mycoplasma biotype 7 and M. putrefaciens) - Molecular diagnosis (PCR) and identification.
Mycoplasmas are bacteria without cell wall and a very small genome, among which are several producing species diseases in animals and in people, most require special laboratory conditions, with means of complex cultures indefinite, because of its limited capacity biosynthesis, and long enough compared to other bacteria (days or weeks). The slow development hinders their phenotypic identification tests metabolic forcing developing serological methods using species - specific antibodies to characterize their antigens. However, serological identification methods encounter the drawback existing cross reactions between subspecies and antigenicity types, along with existing high antigenic heterogeneity within some types and subspecies. Today, serological methods are being replaced by molecular methods of amplification and DNA sequencing. Thus, by comparison of the 16S rRNA sequence it was concluded that Mycoplasma mycoides subsp. mycoides LC biotype (Large colonies) and Mycoplasma mycoides subsp. capri, share 99.9% homology and should be considered two phenotypes of the same subspecies.
Several species of interest in animal diseases. Among them are:
- Mycoplasma agalactiae, contagious agalactia agent (CA: Contagious agalactia), to produce a primary mastitis, sometimes accompanied by secondary arthritis and keratitis in sheep and goats, extended in the Mediterranean area. This species, Mycoplasma agalactiae, seems to be the only producing species of this process in sheep. In goats can provoke this species along with others described below.
- Mycoplasma mycoides "cluster". This group shares antigenic characteristics detected by serologic cross - reactions makes difficult their differentiation. In it you group currently six different subspecies:
- Mycoplasma mycoides subsp. mycoides large colony biotype (Large colonies biotype), producer of contagious agalactia. This subspecies is currently considered equivalent to the previous subspecies Mycoplasma mycoides subsp. capri, since they share 99.9% homology to 16S rRNA level.
- Mycoplasma mycoides subsp. capricolum, (syn. Mycoplasma capricolum s
- Mycoplasma mycoides subsp. capripneumoniae, producer of contagious pleuropneumonia (CCPP: Contagious caprine pleuroppneumonia) in goats.
- Mycoplasma mycoides subsp. mycoides small colonies biotype (biotype Small Colony), producer of contagious bovine peripneumonia in bovines.
- Mycoplasma spp. bovine type 7, producer pneumonitis, mastitis, arthritis and abortions in dairy cows Australia.
- Mycoplasma putrefaciens, also considered within the group of Mycoplasma mycoides to have a high sequence similarity and on 16S rRNA intergenic spacer region (ISR: intergenic Spacer Region) 16S-23S. It is also causing contagious agalactia, but have not described eye damage.
Two other species, Mycoplasma and Mycoplasma cottewii yeatsii, are closely related to Mycoplasma putrefaciens, but does not belong to Mycoplasma mycoides group.
Agalactia contagious CA: Contagious agalactia) is a serious infectious disease in sheep and goats, characterized by mastitis, arthritis and keratoconjunctivitis, with worldwide distribution, with a high impact in Europe, North Africa and Western Asia, which spreads rapidly in herds, so it is important to have specific and rapid diagnostic procedures to detect infection.
This process has several causes species including Mycoplasma agalactiae. When it produced by the subspecies Mycoplasma mycoides subsp. mycoides large colony biotype (Large colonies), Mycoplasma mycoides subsp. capricolum, agalactia usually associated with clinical signs of respiratory distress. In areas where this process is endemic asymptomatic mastitis usually produce only rarely associated with clinical signs of arthritis or keratoconjunctivitis.
Asymptomatic infected animals can eliminate mycoplasmas for many years after initial infection and therefore play an important role in the epidemiology of this process, making it difficult to prevention and eradication.
Recommended tests for diagnosis:
Serodiagnosis to detect antibodies by several methods available (ELISA, inhibition deo growth, etc.), is limited by the cross-Mycoplasma agalactiae, Mycoplasma bovis reactions and subspecies group Mycoplasma mycoides. Furthermore seroconversion is late and only significant antibodies past 25 or 30 days are detected.
The methods of DNA amplification are very useful for distinguishing subspecies of Mycoplasma mycoides group. They also prevent cross - reactivity and variability inherent in serological identification methods, and at the same time allow easier standardization between laboratories.
Tests in IVAMI:
- Molecular diagnostics using PCR.
- In case of mastitis, breast exudate, milk or milk products (cheese).
- If respiratory disorder, respiratory exudate.
- In arthritis, joint exudate taken by puncture (0.5 to 1 mL sterile tube).
Preservation and shipment of sample:
- Refrigerated (preferred) for less than 2 days.
- Frozen: over 2 days.
- Molecular diagnosis (PCR): 24 to 48 hours.
- Molecular identification (sequencing): 4 to 5 days.
Cost of the test: