(P75) High bacterial load in Neisseria gonorrhea and Chlamydia trachomatis co-infections does not influence symptoms

Tuesday, July 25, 2023

16:00 – 18:00 CST

Primary Presenter(s)

Petra FG Wolffs, PhD (she/her/hers)

Medical Molecular Microbiologist
Maastricht University Medical Center+
Maastricht, Netherlands

Co-Author(s)

Anne Dirks

MD. PhD.
Maastricht UMC+
Maastricht, Limburg, Netherlands

Co-author(s)

Hv

Helke van Dessel
Iv

Inge HM van Loo

Maastricht University Medical Center+, Netherlands
Bv

Brian MJW van der veer

Maastricht University Medical Center+, Netherlands
CH

Christian JPA Hoebe, MD PhD

Professor Infectious Disease Control
Maastricht University
Maastricht, Limburg, Netherlands
ND

Nicole Dukers-Muijrers

South Limburg Public Health Service, United States
PS

Paul HM Savelkoul

Maastricht University Medical Center+, Netherlands

Background

N.gonorrhea (NG) and C.trachomatis (CT) co-infections are reported in up to 40% in high risk groups. Little is known about NG and CT co-infections with regard to symptoms and the bacterial load. Here, we quantified NG bacterial loads in oropharyngeal, anorectal, and genital samples and related this to CT co-infections and reported symptoms in a large number of male and female patients.

Methods

All NG-positive patients who attended the South Limburg STI clinic in the Netherlands between January 2012 and December 2021 were included, including their questionnaire data on sex and symptoms. Samples were tested for CT/NG with the Cobas 4800 (Roche Diagnostics, Basel, Switzerland) and the load was quantified by entering the quantification cycle (Cq) values into a standard curve. Chi-square test was used for comparison of symptoms and the Mann-Whitney test for pairwise comparisons of bacterial load.

Results

Of the 3224 included NG positive samples, 79% (n=2552) were from males and 17% (n=542) were CT positive. 1174 (36.4%) were anorectal swabs, 1013 (31.4%) were oropharyngeal swabs, 688 (21.3%) urines and 349 (10.8%) vaginal swabs.

Median load (log10 CFU/ml) per material for NG+/CT+ samples was: anorectal swab 4.6(3.7-5.3), vaginal swab 4.3(3.7-4.7), urine 5.5(5.1-5.8), oropharyngeal swab 2.9(2.5-3.6). In NG+/CT- samples, median load per material was (log10 CFU/ml): anorectal swab 4.0(2.8-5.1), vaginal swab 4.1(3.1-4.8), urine 5.5(5.1-5.8), oropharyngeal swab 2. 7(2.3-3.6).

The NG bacterial load was higher in NG+/CT+ anorectal samples compared to NG+/CT- anorectal samples (p < 0.001), and only marginally higher in NG+/CT- vaginal swabs (p=0.052).

Symptoms were reported equally frequent in NG+/CT- and NG+/CT+ infections (all p >0.05): oropharyngeal (9%,5%), urogenital (64%,63%) and anorectal (23%,27%).

Conclusion

This is the largest study that describes the effect of CT-coinfections on NG infections regarding symptoms and NG load.

NG+/CT+ co-infections demonstrated a higher NG load in anorectal samples compared to NG+/CT- infections. The bacterial load was similar in urogenital and oropharyngeal samples. However, symptoms were reported equally frequent in NG+/CT- and NG+/CT+ infections for all sample types.

Whether NG/CT-interaction causes the higher NG load or whether high risk sexual behavior results in both co-infection and higher NG load remains to be established.