Resistance to penicillin has become an important factor in the epidemiology of gonorrhea. Among military personnel stationed in the El Paso area, the finding of resistance in vitro was seen to be correlated with poor clinical outcome. No failures followed initial treatment with 2.5 million units. But when 1.0 million units of procaine penicillin G, or 600,000 of both procaine plus benzathine penicillin, were used, 15% failed. Further inquiry disclosed that these failures involved organisms having a minimal inhibitory concentration of 0.10 unit/ml or greater. Although sought for, no organism of the tribe Mimea was isolated during this study; this was curious because a number of these men had earlier been stationed in the Far East and Europe where such organisms have been reported frequently.
Sokoloff B, Goldstein H. Clinicolaboratory Study of Acute Gonorrhea in Men in the El Paso, Tex., Area. JAMA. 1963;184(3):197-200. doi:10.1001/jama.1963.03700160073011