Grant: CIHR Fellowship

Gonorrhea is a sexually-transmitted infection that affects over 100 million people world-wide. Due to widespread antibiotic resistance, only one treatment approach is still effective against the causative bacteria (Neisseria gonorrhoeae). Recent studies are inconclusive; some suggest it is mainly acquired during antibiotic treatment, while others suggest it is mainly transmitted from person to person. Experimental data using animal models suggest some resistant strains are more fit, potentially making it easier for them to be transmitted than sensitive strains. Understanding these factors is critical to develop effective public health interventions. To address this, I will examine the genome (DNA) of N. gonorrhoeae from persons diagnosed in Australasia between 2013-2015. First, I will develop the bioinformatics workflow to analyze this genetic data. In order to determine how much drug resistance is due to transmission of already-resistant bacteria, I will then identify or refute transmission between individuals by considering how closely related their bacteria is to one another, their drug resistance profile and epidemiological contact. Next, I will apply these methods to a public health surveillance project for Victoria, Australia, wherein epidemiologic data (e.g., sex, HIV, number of sexual contacts) will be collected along with corresponding bacterial DNA. Using these data, I will identify who infected whom and use regression to assess potential differences in the number of secondary cases (people infected by others) between persons with resistant and sensitive strains, accounting for patient-level risk factors for transmission. This study will contribute to our understanding of transmission of drug-resistant strains. If there is evidence of greater transmissibility of drug-resistant strains, independent of patient characteristics, this will further support the need for rapid antibiotic testing and help public health prioritize contact investigation.