MYCOPLASMA

By Dr. Oduyebo

Mycoplasma
Bacteria without cell wall (Mollicutes)
Smallest free living organisms
Some of human origin, some of animal origin
4 important species

SPECIES
M. pneumoniae
M.hominis
U.urealyticum (Ureaplasma urealyticum)
M.genitalium

Characteristics
Very small
Highly pleomorphic
Contains sterol required for growth
Resistant to penicillin
Inhibited by tetracycline or erythromycin
Can reproduce in cell free media
Use glucose as source of energy, ureaplasma requires urea

Growth requirement
Cell free media which contain lipoprotein & sterol
Heart infusion peptone broth with 2% agar, containing 30% human ascitic fluid or animal serum (horse, rabbit)

Epidemiology
Worldwide distribution
Infection rate 50-90%
Pneumonia incidence (3-30%)
Pneumonia in persons 5-20years

Pathogenesis
Transmission by means of infected respiratory secretions
Organism attaches to receptor on surface of epithelial cells
Attachment made possible by a specialised organelle at one end of the organism
Mixture of adhesins and proteins
Incubation period 1-3 weeks

Clinical findings
Asymptomatic infection
Pneumonia generally a mild disease
Atypical pneumonia (walking pneumonia)
Fever, headache, sore throat
Cough dry, blood streaked sputum,
Chest pain, striking consolidation
Illness resolves over 1-4weeks

Complications
Hemolytic anaemia, neurologic involvement, carditis, pancreatitis

LAB FINDINGS
Specimen -respiratory secretions
Culture –not routinely
Serology -complement fixation test, immunofluorescent test, haemaglutination test.

TREATMENT -tetracycline, erythromycin
PREVENTION -preventing contact with cases
Ureaplasma urealyticum
Requires 10%urea for growth
Common in the female genital tract but no disease
Urethritis in men (NGU – nongonococcal urethritis)