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P3.263 Do Men Harbour the Same Strain of Gonococcus at Multiple Anatomical Sites?
  1. K Eastick
  1. Scottish Bacterial STI Reference Laboratory, Royal Infirmary of Edinburgh, Edinburgh, UK

Abstract

Background All N. gonorrhoeae clinical isolates in Scotland are routinely typed by Neisseria gonorrhoeae multi-antigen sequence typing (NG-MAST). The frequency with which individuals harboured the same N. gonorrhoeae strain at > 1 anatomical site concurrently was examined.

Methods Episodes of gonorrhoea between 2004 and January 2013 comprising typed isolates from two or more anatomical sites of the same male individual submitted within a one-month period were analysed for similarity.

Results 410 episodes of gonorrhoea were identified with > 1 site cultured. The table shows differences in sequence type (ST) within episodes. Forty episodes with three cultures are included in all three pairwise combinations. Overall 91.2% of episodes had identical STs at all sites.

Where STs differed at only one allele, the sequences were compared using CLUSTALW. Thirteen of 14 alleles compared were at the porB locus. Nine pairs were 99.8% similar, representing a difference of 1 nucleotide. The remaining pairs showed 88.4%, 98.2%, 97.8%, 96.9% and 75.1% (tbpB) similarity.

Conclusion A large majority of patients harbour the same ST of N. gonorrhoeae at all sites cultured. In a further 2.2% of patients there is minimal variation, which would be consistent with mutation of the porB gene during the course of infection. This uniformity is not necessarily due to infection from the same partner, as some STs circulate widely.

This data adds to the understanding of the ecology of N. gonorrhoeae in an era where patients positive by nucleic acid amplification tests often receive limited culture for typing and susceptibility testing and assumptions may be made about the strain infecting uncultured sites. This data adds to knowledge of the frequency of mutation of the porB locus in vivo and the frequency of concurrent gonococcal infections with different strains.

Abstract P3.263 Table 1
  • gonorrhoea
  • Neisseria gonorrhoeae
  • NG-MAST

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