Mycoplasma hyopneumoniae may be a species of bacteria known to cause the disease porcine enzootic pneumonia, a highly contagious and chronic disease affecting pigs. As with other mollicutes, M. hyopneumoniae is little in size (400–1200 nm), features a small genome (893–920 kilo-base pairs (kb)) and lacks a cell membrane. It is difficult to grow in laboratories due to its complex nutritional requirements and the high chances of contamination associated with mycoplasma culture. To successfully grow the bacterium, an environment of 5–10% carbon dioxide is required, and the medium should demonstrate an acid color shift. This bacterium may be a concern within the livestock industry because it causes a big reduction within the growing weight of pigs. Losses in the U.S. have been previously estimated at 200 million to 1 billion dollars per annum. Porcine enzootic pneumonia is endemic worldwide and M. hyopneumoniae is present in almost every pig herd. Treatment of this disease is restricted to antibiotics, which are currently ineffective as they are doing not completely remove the infection. Vaccines are found to scale back the severity of the disease but don't prevent the disease from occurring in infected pigs.