A-305 Chlamydia trachomatis and Neisseria gonorrhoeae: An Epidemiological Approach to Mono and Co-Infection

Abstract Background Chlamydia trachomatis and Neisseria gonorrhoeae are the most common bacterial causes of sexually transmitted infections (STIs) worldwide. These exclusively human pathogens cause cervicitis in women and urethritis in men, with asymptomatic and extragenital infections being common. Despite years of research, no vaccine is available. The development of new therapies and vaccines against C. trachomatis and N. gonorrhoeae remains a critical public health concern. The aim of this study was to describe the frequency of detection of C. trachomatis and N. gonorrhoeae in mono- and co-infection in different age groups, using data from a Brazilian laboratory database. Methods A total of 35,305 specimens were analyzed between January 2023 and December 2024, with simultaneous requests for detection of C. trachomatis and N. gonorrhoeae. Pathogen detection was performed by polymerase chain reaction (PCR) using the Roche cobas® 4800 CT/NG Amplification/Detection Kit according to the manufacturer*s guidelines. Analyses were performed by correlating positivity rates with the site of infection, gender and age of the individuals. Results Of the the 35,305 samples analyzed, 13.97% (4,933/35,305) were positive for at least one of the infectious agents. Mono-infection by N. gonorrhoeae was detected in 61.95% (3,056/4,933) and by C. trachomatis in 26.82% (1,323/4,933) of the positive cases, while co-infection cases represented 11.23% (554/4,933) of the positive cases evaluated. The main sites of infection were: anal region, urine, oropharynx, and urethra. The male sex was the most affected by both mono- and co-infection, with 81.63% (1,080/1,323) testing positive for C. trachomatis only, 89.66% (2,740/3,056) for N. gonorrhoeae only, and 85.37% (473/554) for both pathogens. The age group with the highest prevalence was between 21 and 40 years in for both groups, with mono-infection accounting for 80.24% (3,514/4,379) and co-infection for 81.76% (453/554) of positive results, regardless of gender. Conclusion This study showed high rates of mono- and co-infection by C. trachomatis and N. gonorrhoeae, demonstrating that both infections, either separately or together, are common. Men were more affected, probably due to more noticeable symptoms, whereas women are often asymptomatic. The highest prevalence was found in individuals aged 21 to 40 years with similar patterns in mono-infection and co-infection, suggesting that the risk of contracting both pathogens simultaneously is the same. These findings emphasize the need for equal focus on prevention and treatment of both infections to control these often co-occurring diseases.