Molecular epidemiology of sexually transmitted human papillomavirus in a self referred group of women in Ireland

Background: Human papillomavirus (HPV) causes cervical cancer and external genital warts. The purpose of this study is to document the genotype distribution of HPV in females aged between 18 and 34 who self-referred to an STI clinic with visible external genital warts (EGW). Scrapings were taken from visible external genital warts (EGW). These scrapings were analysed by PCR for the presence of HPV DNA. Positive samples were then genotyped by means of a commercially available assay (LiPA). A comparison of genotyping results determined by the LiPA assay and direct amplicon DNA sequencing was also performed. Results: Ninety-two patients out of 105 samples (88%) had detectable levels of HPV DNA. The majority of individuals with EGW (66%) showed the presence of two or more genotypes. The most common HPV genotypes present in the study population were HPV-6, HPV-11, HPV-16, HPV-18, HPV-33 and HPV-53. Potential effects of vaccination on HPV molecular epidemiology indicate that 40% of the patients could have been protected from the high risk genotypes HPV-16 and HPV-18.Conclusion: This is the first report of the molecular epidemiology of external genital warts in women aged between 18 and 34 from Ireland based on results from a LiPA assay. The study shows that most individuals are infected with multiple genotypes including those with high oncogenic potential and that the newly available HPV vaccines could have a significant impact on prevalence of the most common HPV genotypes in this study population.

Epidemiology and comparative analysis of Yersinia in Ireland

Yersiniosis is an acute or chronic enteric zoonosis caused by enteropathogenic Yersinia species. Although yersiniosis is predominantly associated with gastroenteric forms of infection, extraintestinal forms are often reported from the elderly or patients with predisposing factors. Yersiniosis is often reported in countries with cold and mild climates (Northern and Central Europe, New Zealand and North of Russian Federation). The Irish Health Protection Surveillance Centre (HPSC) currently records only 3-7 notified cases of yersiniosis per year. At the same time pathogenic Yersinia enterocolitica is recovered from pigs (main source of pathogenic Y. enterocolitica) at the levels similar to that observed in Yersinia endemic countries. Introduction of Yersinia selective culture procedures may increase Yersinia isolation rates. To establish whether the small number of notifications of human disease was an underestimate due to lack of specific selective culture for Yersinia we carried out a prospective culture study of faecal samples from outpatients with diarrhoea, with additional culture of appendix and throat swabs. Higher levels of anti-Yersinia seroprevalence than yersiniosis notification rates in endemic countries suggests that most yersiniosis cases are unrecognised by culture. Subsequently, in addition to a prospective culture study of clinical specimens, we carried out serological screening of Irish blood donors and environmental screening of human sewage. Pathogenic Yersinia strains were not isolated from 1,189 faeces samples, nor from 297 throat swabs, or 23 appendix swabs. This suggested that current low notification rates in Ireland are not due to the lack of specific Yersinia culture procedures. Molecular screening detected a wider variety of Y. enterocolitica-specific targets in pig slurry than in human sewage. A serological survey for antibodies against Yersinia YOP (Yersinia Outer Proteins) proteins in Irish blood donors found antibodies in 25%, with an age-related trend to increased seropositivity, compatible with the hypothesis that yersiniosis may have been more prevalent in Ireland in the recent past. Y. enterocolitica is a heterogeneous group of microorganisms that comprises strains with different degree of pathogenicity. Although non-pathogenic Y. enterocolitica lack conventional virulence factors, these strains can be isolated from patients with diarrhoea. Insecticidal Toxin Complex (ITC) and Cytolethal Distending Toxins can potentially contribute to the virulence of non-pathogenic Y. enterocolitica in the absence of other virulence factors. We compared distribution of ITC and CDT loci among pathogenic and non-pathogenic Y. enterocolitica. Additionally, to demonstrate potential pathogenicity of non-pathogenic Y. enterocolitica we compared their virulence towards Galleria mellonella larvae (a non-mammalian model of human bacterial infections) with the virulence of highly and mildly pathogenic Y. enterocolitica strains. Surprisingly, virulence of pathogenic and non-pathogenic Y. enterocolitica in Galleria mellonella larvae observed at 37°C did not correlate with their pathogenic potential towards humans. Comparative phylogenomic analysis detects predicted coding sequences (CDSs) that define host-pathogen interactions and hence providing insights into molecular evolution of bacterial virulence. Comparative phylogenomic analysis of microarray data generated in Y. enterocolitica strains isolated in the Great Britain from humans with diarrhoea and domestic animals revealed high genetic heterogeneity of these species. Because of the extensive human, animal and food exchanges between the UK and Ireland the objective of this study was to gain further insight into genetic heterogeneity and relationships among clinical and non-clinical Y. enterocolitica strains of various pathogenic potential isolated in Ireland and Great Britain. No evidence of direct transfer of strains between the two countries was found.