Comparison of the sensitivity of two methods for isolation of Mycoplasma pneumoniae

Throat swab specimens from 1,494 Marine Corps recruits were inoculated into vials containing diphasic (broth/agar) mycoplasma medium and also onto PPLO agar plates, which were subsequently overlayed with sheep erythrocytes in saline agar. Strains of Mycoplasma pneumoniae were isolated from 89 (6%) of the specimens by one or both of the methods. Eight-one of the 89 (91%) positive specimens were cultured with diphasic medium, whereas only 42 (47%) were cultured with the overlay method (x2 = 7.44, P less than 0.01). The diphasic system for isolation of M. pneumoniae should be the method of choice in clinical and research application.