Background

Mycoplasmas and Ureaplasmas are organisms that differ from other bacteria in that they lack a rigid cell wall. They are classified in the class Mollicutes. The name Mollicutes means soft skin, referring to the lack of a rigid bacterial cell wall. Additionally, the genome size is quite small compared to other bacteria. The average genome size in Mycoplasma is 600-1700 Kb while other bacteria have genomes ranging in size from 4000-6000 kb. It has been hypothesized that ancestral Mycoplasma evolved from a Bacillus-Lactobacillus-Sterptococcus phylogenic origin 600 million years ago based on similarities in the ribosomal RNA sequences. The smaller genome size probably resulted from selective pressure for energy economy, faster multiplication and the ability to grow in environments with limited nutritional elements. Mycoplasmas and Ureaplasmas have been recovered from humans, animals, birds, insects, and plants. There are some free-living species that were isolated from water and soil as well. There have been many studies implicating Mycoplasma in autoimmune conditions via molecular mimicry and clinicians have a great interest in learning about the Mycoplasma status of patients with autoimmune conditions or chronic fatigue syndrome.

Respiratory Tract:

Several mycoplasmas have been detected in the oral cavity and were not linked to clinical symptoms. Although many of the mycoplasma species are considered normal flora, the same species could cause clinical symptoms in some individuals and act as opportunistic agents in immunocompromised patients. Mycoplasma pneumoniae causes 20% of all community-acquired pneumoniae and about half of the pneumoniae cases in certain confined groups. The most typical clinical symptom is tracheobronchitis. The incubation period is two to three weeks and the organism can persist for several months and sometimes for years in hypogammaglobulinemic patients. Infections could cause extrapulmonary complications such as meningoencephalitis, ascending paralysis, transverse myelitis, pericarditis, hemolytic anemia, arthritis and mucocutaneous lesions. Strong evidence exists for the presence of Mycoplasma pneumoniae in other extrapulmonary sites through the use of polymerase chain reaction which can detect 5 or less copies of the mycoplasma genome in the sample. Other mycoplasma species such as Mycoplasma fermentans have been isolated from children with or without clinical signs and from HIV patients.

Genitourinary Infections:

Ureaplasma spp. and Mycoplasma Hominis can be isolated from the lower genital tract of sexually active adults following puberty. Mycoplasma genitalium has been detected by PCR more often in Urethral specimens from men with acute non-gonococcal urethritis than those with urethritis. Mycoplasma genitalium has also been linked to cervicitis and endometritis by serological data.

Systemic Infections and Immunosuppressed Hosts:

Extrapulmonary and extragenital mycoplasmal infections occur in immunocompromised patients. There is strong evidence that mollicutes can cause invasive disease in the joints and respiratory tract leading in some instances to bacteremia especially in patients with hypoglobulinemia. Mycoplasma hominis has been detected in some wound infections in immunocompromised patients. Mycoplasmas are the main cause of septic arthritis in patients with congenital antibody deficiency. Mycoplasma hominis has been detected in patients following renal transplants, trauma and genitourinary manipulations. Several Mycoplasma species, including Mycoplasma fermentans, Ureaplasma urealyticum and Mycoplasma salivarium have been detected by culture or PCR in synovial fluid collected from patients with rheumatoid arthritis. There has been a great interest in Mycoplasma penetrans and Mycoplasma fermentans in HIV infected individuals, with or without AIDS.

When collecting vaginal samples, care should be taken to avoid collection of contaminating lubricants and antiseptics commonly used in gynecologic practice. Calcium Alginate, Darcon, or polyester swabs with aluminum or plastic shafts are preferred.

Transport:

EDTA blood (3-5 mls) should be shipped overnight on blue ice (ice packs). Patient needs to be off antibiotics for at least three weeks for most reliable results. Fluids from other sources (Synovial, CSF or other) can also be sent overnight on ice for PCR testing.