Oxidase positive rods from cases of suspected gonorrhoea. A comparison of conventional, gas chromatographic and genetic methods of identification

Abstract

Genito-urethral specimens from 3260 women and 1170 men, with ailments suggestive of gonorrhoea, were examined for growth of oxidase positive rodshaped bacteria, as well as of gonococci. Moraxella osloensis was identified in 26 cases (0.64 per cent of women and 0.43 per cent of men). Three patients harboured phenylalanine negative (or weakly reacting) and tryptophan deaminase negative M. phenylpyrouvica and, in three cases, a Flavobacterium species was detected. Among six oropharyngeal specimens from patients suspected of gonorrhoea, two yielded growth of oxidase positive rods, Kingella kingae and Neisseria elongata, respectively, N. gonorrhoeae was isolated from 537 patients, i.e., 12.1 per cent of all cases. The isolates of oxidase positive rods were in most cases completely identified by streptomycin resistance transformation. On this basis, the diagnostic reliability of some morphological and cultural-biochemical tests and gas chromatography was examined. Gas chromatographic analysis of fatty acid and alcohol composition of whole cells proved distinctive of species defined genetically, irrespective of confusing behaviour of some strains in other tests.