Gonococcal Genetic Island in the Global Neisseria gonorrhoeae Population: A Model of Genetic Diversity and Association with Resistance to Antimicrobials

Abstract

The aim of this work was to study the genetic diversity of the gonococcal genetic island (GGI) responsible for the type IV secretion system (T4SS) and the association of a functionally active GGI with antimicrobial resistance. An analysis of the GGI in a sample of 14,763 genomes of N. gonorrhoeae isolates from the Pathogenwatch database collected in 1996–2019 from 68 countries was performed. A model of GGI’s genetic diversity that divides the global gonococcal population into fifty-one GGI clusters and three GGI superclusters based on the allele type of the traG gene and substitutions of the atlA and ych genes for eppA and ych1 has been proposed, reflecting differences among isolates in the T4SS functionality. The NG-MAST and MLST typing schemes (with accuracies of 91% and 83%, respectively) allowed the determination of both the presence of a GGI and the GGI cluster and, correspondingly, the structure of the GGI and the ability to secrete DNA. A statistically significant difference in the proportion of N. gonorrhoeae isolates resistant to ciprofloxacin, cefixime, tetracycline, and penicillin was found when comparing populations with a functional and a non-functional GGI. The presence of a functional GGI did not affect the proportion of azithromycin-resistant isolates.