The Gonococcal Genetic Island defines distinct sub-populations of Neisseria gonorrhoeae

The incidence of gonorrhoea is increasing at an alarming pace, and therapeutic options continue to narrow as a result of worsening drug resistance. is naturally competent, allowing the organism to adapt rapidly to selection pressures including antibiotics. A sub-population of carries the Gonococcal Genetic Island (GGI), which encodes a type IV secretion system (T4SS) that secretes chromosomal DNA. Previous research has shown that the GGI increases transformation efficiency , but the extent to which it contributes to horizontal gene transfer (HGT) during infection is unknown. Here we analysed genomic data from clinical isolates of to better characterize GGI+ and GGI- sub-populations and to delineate patterns of variation at the locus itself. We found the element segregating at an intermediate frequency (61%), and it appears to act as a mobile genetic element with examples of gain, loss, exchange and intra-locus recombination within our sample. We further found evidence suggesting that GGI+ and GGI- sub-populations preferentially inhabit distinct niches with different opportunities for HGT. Previously, GGI+ isolates were reported to be associated with more severe clinical infections, and our results suggest this could be related to metal-ion trafficking and biofilm formation. The co-segregation of GGI+ and GGI- isolates despite mobility of the element suggests that both niches inhabited by remain important to its overall persistence as has been demonstrated previously for cervical- and urethral-adapted sub-populations. These data emphasize the complex population structure of and its capacity to adapt to diverse niches.