Eurosurveillance - Volume 23, Issue 6, 08 February 2018

One of the most common sexually transmitted pathogens disproportionately affecting young people is Chlamydia trachomatis (CT). This study aimed to assess prevalence of CT among sexually active students (aged 18–19 years) in their final years of high school education in Warsaw and Krakow. Methods: The sample was selected from 61 clusters, each cluster representing one school. We described city, sex, type of school and their association with CT prevalence. To account for non-responders we applied inverse probability weighting. Results: Our study population consisted of 3,136 young adults eligible for CT screening, of whom 2,326 reported having had sexual intercourse within past 12 months. Of the 950 students who agreed to be tested, 39 were infected with CT. Weighted prevalence of CT was 3.9% (95% confidence interval (CI): 2.7–5.1); however, prevalence in the students in Warsaw (6.6%; 95% CI: 3.5–12.4) was six times higher (prevalence ratio (PR) = 5.9; 95% CI: 2.0–17.3) than in Krakow (1.1%; 95% CI: 0.5–2.6). In both settings, female students attending vocational-technical schools were most affected; the prevalence in this group was more than five times higher (PR = 5.2; 95% CI: 1.7–15.6) compared with female peers in high schools and more than three times higher (PR = 3.3; 95% CI: 1.0–10.7) compared with male peers attending vocational-technical schools. Conclusion: Our study suggested prevalence of CT infection among young people in Poland comparable with the European average, supporting implementation of a CT control programme as recommended in international guidelines.

Plasmid-mediated colistin resistance mechanisms have been identified worldwide in the past years. A multiplex polymerase chain reaction (PCR) protocol for detection of all currently known transferable colistin resistance genes (mcr-1 to mcr-5, and variants) in Enterobacteriaceae was developed for surveillance or research purposes. Methods: We designed four new primer pairs to amplify mcr-1, mcr-2, mcr-3 and mcr-4 gene products and used the originally described primers for mcr-5 to obtain a stepwise separation of ca 200 bp between amplicons. The primer pairs and amplification conditions allow for single or multiple detection of all currently described mcr genes and their variants present in Enterobacteriaceae. The protocol was validated testing 49 European Escherichia coli and Salmonella isolates of animal origin. Results: Multiplex PCR results in bovine and porcine isolates from Spain, Germany, France and Italy showed full concordance with whole genome sequence data. The method was able to detect mcr-1, mcr-3 and mcr-4 as singletons or in different combinations as they were present in the test isolates. One new mcr-4 variant, mcr-4.6**, was also identified. Conclusions: This method allows rapid identification of mcr-positive bacteria and overcomes the challenges of phenotypic detection of colistin resistance. The multiplex PCR should be particularly interesting in settings or laboratories with limited resources for performing genetic analysis as it provides information on the mechanism of colistin resistance without requiring genome sequencing.