Unique gonococcal phenotype associated with asymptomatic infection in men and with erroneous diagnosis of nongonococcal urethritis

The percentage of gonococcal isolates in King County, Washington, requiring citrulline and uracil (CU auxotype) increased from 1.6% in 1986 to 16.5% i n 1997. Among men, urethral infection with the CU auxotype (n = 93), in com parison with infection by other auxotypes (n = 1211), was associated with c oexisting chlamydial infection, younger age, heterosexual contact, and fewe r new recent partners (P < .05). Among heterosexual men, urethral infection with the CU auxotype, compared with infection with other auxotypes, less o ften produced symptoms of urethral discharge (75% vs. 92%) or dysuria (47% vs. 74%) or signs of moderate or profuse urethral discharge (57% vs. 89%, P < .05 for each comparison), produced symptoms of longer duration (7.0 vs. 4.5 days, P < .01), less often resulted in urethral smears showing gram-neg ative intracellular diplococci (67% vs. 95%, P < .01), and thus more often was erroneously diagnosed as nongonococcal urethritis. Several mechanisms c ould explain reduced inflammatory response to the CU auxotype and its recen t spread.