LAUSR

Background Recently it was proposed that patients repeatedly infected with Chlamydia trachomatis(CT) or Neisseria gonorrhoeae(NG), so called core groups, likely have high impact on circulating STIs within the population. To substantiate such proposition, more information is needed on (1) whether the characteristics of those single infected patients differ from the repeat infected patients and (2) the proportion of patients who were not retested. Methods Laboratory data from all CT/NG tests by the STI clinic, general practitioners or hospital physicians between 2011–2016 of patients aged 15–64 years were obtained (24,051 tests: 2,317 CT positive, 405 NG positive). The outcome ‘repeatedly infected’ was defined as patients with ≥2 CT or ≥2NG infections. Chi-square tests were used to compare characteristics of repeatedly infected versus single infected patients, for CT and NG separately. Results Patients with repeat CT-infections 12%(215/1,845) were more often women, HIV positive, NG positive, diagnosed at the STI clinic or hospital compared to the GP, had ≥1 sex partner, reported urogenital symptoms, proctitis and oropharyngeal symptoms (p<0.05). Of the patients with a single CT infection, 50%(814/1,630) was not retested. Patients with repeat NG-infections 13%(38/296) were more often men, older (≥25 years), living in non- and modest urban areas, HIV positive, diagnosed at the STI clinic or hospital and reporting oropharyngeal symptoms (P<0.05). Of the patients with a single NG infection, 27%(69/258) was not retested. Conclusion Patients with repeat CT/NG infections differed from patients with a single infection. Also, characteristics of repeatedly infected patients differed between CT and NG. Indeed, patients with repeat CT or NG infections have impact on STI transmission. However, 27–50% of CT/NG positive patients were not retested. Probably those patients also have impact on circulating STIs, as reinfections are common. Focus should be on infected patients who do not retest or even not test at all as they enable ongoing transmission. Disclosure No significant relationships.