Mycoplasma hyopneumoniae

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A Microbial Biorealm page on the genus Mycoplasma hyopneumoniae

Classification

Higher order taxa

Bacteria; Firmicutes; Mollicutes; Mycoplasmatales; Mycoplasmataceae; Mycoplasma

Genus and Species

Genus species: Mycoplasma hyopneumoniae

Strains: Mycoplasma hyopneumoniae 232, Mycoplasma hyopneumoniae 7448, Mycoplasma hyopneumoniae J,

NCBI: Taxonomy

Description and significance

Mycoplasma hyopneumoniae is a type of bacteria that has a small genome and does not contain a cell wall. It is found throughout respiratory systems in pigs, such as in the cilia of cells in lungs, and causes coughs and more specifically, enzootic pneumonia (EP). EP is known to cause weight loss in pigs, leading to millions of dollars of losses in the livestock industry. (1)

It is important to sequence the genome of Mycoplasma hyopneumoniae in order to analyze how much the bacteria is involved in respiratory diseases in pigs and to also detect antibodies against the bacteria. (2)

The strains of Mycoplasma hyopneumoniae are isolated using nasal swabs to collect samples from naturally and experimentally infected pigs. The organisms are then isolated in cultures and detected using PCR. Nested PCR (nPCR), specifically, purifies samples to sequence and align them, and then to detect the presence of the mycoplasma. After detecting strains, it is important to analyze how much vaccination affected these strains. The growth of Mycoplasma hyopneumoniae is fairly difficult in the laboratory as the bacteria grows very slowly and requires specific nutrients. (3)

Edited by Jessica Lau, student of Rachel Larsen and Kit Pogliano at UCSD.

Genome structure

Mycoplasma hyopneumoniae 232 has a complete genome. It is circular and the length is 892,758 nucleotides. The GC content is 28%. It has 727 genes.

The replicon type is chromosome.

Edited by Jessica Lau, student of Rachel Larsen and Kit Pogliano at UCSD.

Cell structure and metabolism

Since Mycoplasma hyopneumoniae lacks a cell wall, it cannot perform many metabolic processes seen in other bacterias. As in other mycoplasmas, it contains the minimum amount of organelles needed to survive along with a small genome and tightly coiled chromosomes.

Like all other mycoplasmas, Mycoplasma hyopneumoniae relies solely on its host, the cilia on lung cells, for nutrition and energy.

Mycoplasma hyopneumoniae is known to produce toxic by-products rather than than toxins, as seen in other disease-causing bacterias.

Edited by Jessica Lau, student of Rachel Larsen and Kit Pogliano at UCSD.

Ecology

Mycoplasma hyopneumoniae attaches to the cells in the lungs of pigs. Since there are a few cases of EP per herd of pigs, there are detrimental effects to the economy and livestock industry. (3)

Other species of Mycoplasma' including M. mycoides have also been known to cause diseases in farms, affecting the agriculture industry as well.

Pathology

Mycoplasma hyopneumoniae is a mycoplasma microorganism, signifying that it does not contain a cell wall. This microorganism uses the cilia of epithelial cells lining the lungs as its host. Once attached, it causes cilia to stop functioning, and eventually leads to death of epithelial cells, causing lesions found in pigs infected with enzootic pneumonia (EP). (1)

Symptoms of EP include reduction of growth in pigs and respiratory problems, such as coughing.

Application to Biotechnology

Mildly toxic by-products are produced by Mycoplasma hyopneumoniae to stop the cilia on epithelial cells in lungs from beating. However, antibiotics that target cell walls are ineffective against all Mycoplasmas since they lack cell walls.

Current Research

July 2005: "Dynamics and persistence of Mycoplasma hyopneumoniae infection in pigs". An experiment was performed to determine the persistence of Mycoplasma hyopneumoniae as well as the duration of the disease in pigs. Pigs were placed in direct and indirect contact with the experimentally infected pigs. Pigs that had direct exposure to the disease contracted it within 28 days while the pigs that had indirect exposure contracted the disease after 42 days; PCR was used to detect the presence of the disease. The duration of the disease was also tested by slaughtering random infected pigs and taking nasal swab and lung samples on these days after being infected: 155, 170, 185. Results showed that 77.7% of experimentally infected and 100% of the direct and indirect contact pigs were still infected up to 185 days after being infected. More studies need to be done in order to detect the efficacy of different vaccinations. (1)

January 2004: "Dynamics of Mycoplasma hyopneumoniae infection in 12 farms with different production systems". An experiment was performed to determine how involved Mycoplasma hyopneumoniae is in respiratory problems in pigs and also if different herds are affected in different ways by the microorganism. Samples of blood and nasal swabs from 12 different farms were taken to be analyzed. All 12 farms contained pigs that were infected, but in pigs where Mycoplasma hyopneumoniae played a more direct role in respiratory problems, the number infected was less than that for pigs where Mycoplasma hyopneumoniae played a less direct role. Also, on the farms, a 1-2 site production system showed progressive transmission of the disease while in 3 site systems, the infection was more abrupt. (2)

July 1998: "Detection of Mycoplasma hyopneumoniae in Bronchoalveolar Lavage Fluids of Pigs by PCR". An experiment was performed to determine the best method for identifying the presence of Mycoplasma hyopneumoniae. Using the process of PCR with DNA extracted from the bronchoalveolar lavage fluid (BALF) of pigs, the best results were obtained and the detection of the mycoplasma was possible. However, in samples where the microorganism underwent vaccination or medication, the detection of mycoplasma was effected. (3)

References

1. Eduardo Fano, Carlos Pijoan, and Scott Dee. 2005. "Dynamics and persistence of Mycoplasma hyopneumoniae infection in pigs"Canadian Journal of Veterinary Research, vol. 69, no.3 (223-228)

2. Katrin Baumeister, Martin Runge, Martin Ganter, Anne A. Feenstra, Friedrich Delbeck, and Helga Kirchhoff. 1998. "Detection of Mycoplasma hyopneumoniae in Bronchoalveolar Lavage Fluids of Pigs by PCR"Journal of Clinical Microbiology, vol. 36, no. 7 (1984-1988)

3. Marina Sibila, Maria Calsamiglia,corresponding author Dolors Vidal, Llorenç Badiella, Álvaro Aldaz, and Jens C. Jensen. 2004. "Dynamics of Mycoplasma hyopneumoniae infection in 12 farms with different production systems"Canadian Journal of Veterinary Research , vol.68, no.1 (12-18)

4. "BSc(Hons) Veterinary Pathology" The Royal Veterinary College, University of London

Edited by Jessica Lau, student of Rachel Larsen and Kit Pogliano at UCSD.

KMG