Characterization and Trend of Co-Infection with Neisseria gonorrhoeae and Chlamydia trachomatis from the Korean National Infectious Diseases Surveillance Database

Purpose: We analyzed the database from the Korean National Infectious Diseases Surveillance to reveal clinical characteristics of co-infection with Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT). Materials and Methods: Eligible cases included a single NG infection (male/female) for 6,421 (4,975/1,446), a single CT infection for 20,436 (6,107/14,329), and co-infection for 498 (233/265) between 2011 and 2015. Results: Cases of NG and CT have increased for 5 years; the proportion of co-infected male has increased continuously and was positively correlated with that of CT infections. But the proportion of co-infected female was positively correlated with that of NG infections, following an expanded wavelike-pattern. Generally, people with co-infection was younger than either infection alone (p=0.001). But the characteristics of co-infection revealed sex-specific differences. While the co-infected females were younger than females in NG (p=0.001) or CT group (p=0.001), the co-infected males were younger than males in CT (p=0.001) only, not males in the NG group (p=0.394). Amongst males, 4.47% with NG had CT infection, while in female 15.49% with NG had CT (p=0.001). In contrast, in male 3.68% with CT infection had NG infection and in female 1.82% of CT had NG (p=0.001). Young people in both sexes have increased risks of co-infection bi-directionally (all p=0.001), except males with NG that were also co-infected with CT (p=0.642). Conclusions: The sex-specific findings in co-infection may improve understanding of gender-specific characteristics in NG and CT infections. Co-infected people are increasing for 5 years. Therefore, we must consider long-term complication of the co-infected people.