Relation between nutritional requirements and susceptibilities to antibiotics of strains of Neisseria gonorrhoeae from pharyngeal and anogenital sites.

Auxotyping and antibiotic susceptibility testing was carried out on 100 consecutive isolates of non-penicillinase producing strains of Neisseria gonorrhoeae (non-PPNG) taken on the same occasion from throat and anogenital sites, 100 non-PPNG strains isolated from the throat only, and 100 non-PPNG strains from anogenital sites only. Non-requiring, non-requiring and phenylalanine inhibited, proline requiring, amino acid group requiring, and arginine requiring auxotypes predominated in all groups of patients. Strains of the arginine requiring type found in anogenital sites tended to have additional requirements. The auxotypes and susceptibility to antibiotics of 93 of the 100 paired cultures from the throat and anogenital sites were identical. There appeared to be a slight preponderance of moderately susceptible strains in isolates from the throat. A strong correlation was found between nutritional requirements and sensitivity to antibiotics. Auxotypes of and minimum inhibitory concentrations (MICs) for N gonorrhoeae isolated from the throat were mostly the same as the auxotypes of and MICs for strains that were circulating during the study period in Amsterdam.