Mycoplasma
Mycoplasma has many different shapes because the microbe is absent of cell wall. Morphology and Staining
Shapes of Mycoplasma by scanning electron microscopy
Blue color by Giemsa stain
Mycoplasma is the smallest ( µm) microbe that can grow on artificial cell-free- media and form very small colony on plate. Mycoplasma grow slowly in blood or serum contained media and produce "fried egg" colonies on agar plates. Due to the slow growth, the colonies need 3 weeks to develop. The colonies are extremely small. Culture
Human pathogens There are many species in Mycoplasma in nature. Two genera are recognized as human pathogens: –Mycoplasma –Ureaplasma Mycoplasma pneumoniae Ureaplasma urealyticum
Mycoplasma pneumoniae cause primarily atypical pneumonia in human
Virulent factors P1 protein –an adhering membrane protein Glycolipid antigen –Induce immunopathological injury Capsule –resists phagocytosis and display cytotoxicity
Ureaplasma urealyticum Causes non-gonococcal urethritis (NGU). NGU is a common STD with or without clinical symptoms.
Virulent factors Phospholipase Urease IgA protease
◇ Laboratory diagnosis: Sample: Sputum or throat washings. Microscopy: Direct observation. Serological examination: Cold agglutinin test (IgM auto- antibody in sera of patients) and ELISA (P1 protein as the antigen).
◇ Treatment: Since Mycoplasma lacks cell wall, the penicillins and cephalosporins are ineffective. The common used antibiotics are tetracycline and erythromycin. ◇ Prevention: No vaccines are currently available