Possible effects of antibiotic treatment on the senstivity and growth requirements of Neisseria gonorrhoea.

The decreased sensitivity to penicillin of Neisseria gonorrhoeae has been a cause of concern during recent years. About 25% of strains sent in for routine diagnosis to the Statens Seruminstitut in 1957 were found to require roughly 20 times as much penicillin to inhibit development completely as was required for strains isolated in 1944. The stability of this reduced sensitivity to penicillin was studied in 20 strains which were subcultured daily on medium without penicillin. A comparison was also made between the sensitivity levels to penicillin and streptomycin for 1957 and 1958. A phenomenon possibly resulting from penicillin therapy of gonorrhoea was noted by the authors in June 1957, when they recorded the appearance of atypical strains having special growth requirements, low viability and weak or absent glucose-fermentation. The incidence, serology and sensitivity to antibiotics of these atypical strains were examined; further research on their different behaviour in response to changes in medium, as compared with that of typical strains, may give rise to some interesting findings.