NAME: Mycoplasma hominis
SYNONYM OR CROSS REFERENCE: Pelvic inflammatory disease (PID)(1)
CHARACTERISTICS: M. hominis is an intracellular gram negative pleomorphic bacterium, 0.2 to 0.3 µm in diameter, which belongs to the Mycoplasmataceae family, in the Mollicutes class(2,3). M. hominis is one of the smallest bacteria capable of self-replication, and lacks the genes coding for the cell wall, leading M. hominis to a parasitic and saprophytic existence(2). Instead of a cell wall, it possesses a three-layered membrane containing sterol, which is taken up from the environment. M. hominis is associated to the urogenital mucous membrane, but rarely penetrates the submucosa. M. hominis uses the UGA codon to code for tryptophan instead of a STOP codon(4). On culture medium, M. hominis produce colonies with a "fried eggs" appearance and they metabolize arginine. M. hominis have a symbiotic relationship with Trichonomas vaginalis(5).
PATHOGENICITY/TOXICITY: M. hominis may be implicated in several diseases, although its role is unclear for most of them(1). There is evidence indicating that M. hominis may be implicated in pelvic inflammatory disease, which may cause ectopic pregnancy. This bacterium prospers in the environment created by other gram negative bacteria implicated in bacterial vaginosis and may be a cause of preterm delivery and miscarriage. It may also be implicated in postpartum fever, because it may be a cause of endometritis. M. hominis is also suspected to be the cause of neonatal infections, including conjunctivis, respiratory distress, fever, meningitis, abscesses, and congenital pneumonia, which occurs a few hours after birth. In adults, M. hominis may be implicated in pharyngitis, septicaemia, lung infections, central nervous system infections, other respiratory tract infections, joint infection, and wound infections. M. hominis infections are rare for healthy adults.
EPIDEMIOLOGY: This pathogen occurs worldwide(1,3). Immunocompromised patients and patients with agammaglobulinemia or who are receiving immunosuppressive drugs are particularly at risk. M. hominis does not usually persist in children after birth, but 17% of prepubescent girls are infected with this bacterium(1). Most infections are acquired by sexually active adults, and the risk of colonization increases with the number of partners. Women are more frequently colonized (80%) than men (50%)(2).
HOST RANGE: M. hominis can colonize humans and non-human primates(3).
INFECTIOUS DOSE: Unknown.
MODE OF TRANSMISSION: M. hominis is principally transmitted by sexual contact and cervical and vaginal contact during birth(1). Infections in utero are rare but possible.
INCUBATION PERIOD: Unknown.
COMMUNICABILITY: Vertical transmission from mother to baby is high(6).
RESERVOIR: Humans and non-human primates may contain the pathogens(3).
ZOONOSIS: No zoonoses have been reported for this pathogen, but it is theoretically possible(3).
DRUG SUSCEPTIBILITY: M. hominis is susceptible to tetracycline, clindamycin, and quinolone(7).
SUSCEPTIBILITY TO DISINFECTANTS: Phenolic disinfectants, 1% sodium hypochlorite, 70% ethanol, formaldehyde, glutaraldehyde, iodophore, and peracedic acid are effective against M. hominis(8).
SURVEILLANCE: Monitor for symptoms. Diagnosis can be confirmed by microbial culture and PCR(1).
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: Give appropriate drug therapy(7).
IMMUNIZATION: None available.
PROPHYLAXIS: Clindamycin may be given early in pregnancy for infected women in order to avoid neonatal infection, but the efficacy of this treatment is disputable(1).
LABORATORY-ACQUIRED INFECTIONS: None reported to date.
SOURCES/SPECIMENS: M. hominis may be found in body fluid, swabs, and uro-genital tract tissues.
PRIMARY HAZARDS: Laboratory workers should pay attention to droplets, exposure of mucous membrane, infectious aerosol, parenteral inoculation, and ingestion(2).
SPECIAL HAZARDS: None.
RISK GROUP CLASSIFICATION: Risk Group 2.
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures.
PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to slashes(15).
OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities(15).
SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up (30 min)(15).
DISPOSAL: All material should be decontaminated before disposal with steam sterilization, incineration or chemical disinfection(15).
STORAGE: Samples and biological material should be store in appropriately labelled sealed containers(15).
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
UPDATED: September 2010 PREPARED BY: Pathogen regulation directorate, Public Health Agency of Canada.
Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Public Health Agency of Canada, 2010