Serotypes of Ureaplasma urealyticum isolated from patients with nongonococcal urethritis and gonorrhea and from asymptomatic urethral carriers.

Ureaplasma urealyticum strains isolated from urethral specimens of 112 patients with nongonococcal urethritis, 17 with gonorrhea, and 33 asymptomatic carriers (controls) were tested by the growth-inhibition test with standard ureaplasma antisera (serotypes 1-8). Cases with more than one serotype (two to four types) were encountered in 36.6% of patients with nongonococcal urethritis, 29.4% of those with gonorrhea, and 21.2% of controls. The most frequently recovered serotypes were type 4 from patients with nongonococcal urethritis (57.1%) and type 2 from patients with gonorrhea and controls (35.2% and 36.3%, respectively). The difference in frequency of serotype 4 between patients with nongonococcal urethritis and controls was statistically significant (P less than .001). An additional serotyping with types 9 and 10 antisera of the nontypable strains from patients with nongonococcal urethritis and controls (17.8% and 21.2%, respectively) revealed three type-9 strains. The results show a need for utilization of serotyping of U. urealyticum in studies of the epidemiology and transmissibility of genital infections with U. urealyticum.