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ObjectivesThe detection of an STI agent in a urogenital tract (UGT) specimen from a young child is regarded as being indicative of sexual abuse. However, the probabilities of contamination events that could conceivably lead to STI positive specimens in the absence of sexual contact are unclear. The objective was to estimate the potential for fingers that have come in contact with Chlamydia trachomatis-positive urine to detectably contaminate C. trachomatis-negative urine.MethodsThe study design was based on self-experimentation. Dilutions of C. trachomatis elementary bodies (EBs) were prepared. A participant contacted an EB dilution then a urine surrogate specimen. The experiment was performed by three participants using three C. trachomatis isolates, of genotype E, F and B. Two surrogate urine contact methods were used to mimic contamination of a carer assisting with a child’s urine collection. All EB dilutions and urine surrogate specimens were subjected to C. trachomatis assay and quantification in a real-time PCR-based diagnostic system.ResultsThe amplimer crossing point (Cq) for EB dilutions was 10.0±1.6 less than for corresponding finger contacted urine specimens, which corresponds to ~10 µL of EB suspension transferred. This was largely independent of participant identity, C. trachomatis strain or EB dilution. Hand decontamination led to large reductions in EBs transferred, but transfer remained consistently detectable. Recent Cq data from C. trachomatis-positive clinical urine specimens were collated, and 20% clearly contained sufficient C. trachomatis to detectably contaminate another specimen by finger-mediated transfer, as in this experiment.ConclusionsThis study directly demonstrated the potential for urine contaminated fingers to convert a C. trachomatis-negative urine specimen to C. trachomatis positive as a result of contact. Accordingly, procedures for urine specimen collection, particularly from children, need to be designed to prevent contamination.

The notion that sexually transmitted infections (STIs) can be acquired through non-sexual means is a well-established meme in the public consciousness. The public toilet seat is the most commonly blamed vector. This is despite the lack of evidence for acquisition of STIs from toilet seats, and the ready availability of reputable advice to this effect.1 While the ‘toilet seat hypothesis’ is not currently regarded as supported by data, other modes of non-sexual acquisition of STIs, though rare, have been reported. Examples include pharyngeal gonorrhoea by sharing of confectionery,2 transmission of urogenital (UGT) gonorrhoea by sharing of a sex doll,3 and transmission of Trichomonas vaginalis via the fingers of a traditional healer in west Africa.4 This provides credibility to the notion that STI detection in UGT specimens from young children is not always a consequence of ‘conventional’ sexual contact or, for very young children, vertical transmission. Estreich and Forster5 reviewed relevant evidence and concluded that inferring the cause of an STI in a young child is a ‘complex subject’, with vertical transmission, child sexual abuse and accidental/fomite transmission all conceivable mechanisms. This begs the question that is critical to service providers: How strongly does the presence of an STI in a young child indicate sexual abuse? This dilemma remains a challenge.6 In individual cases, potential modes of non-sexual transmission may be invoked, and the plausibility of these can impact child protection and/or justice system responses. Incorrect interpretation has the potential for a child remaining in an unsafe environment, or conversely leading to a false conclusion that a crime has taken place, resulting in initiation of an investigation. The strong imperatives to avoid either of these errors can create instability in institutional responses, and inappropriate management …

Chlamydia trachomatis causes both urogenital tract (UGT) and ocular infections. One class of ocular infection is trachoma. Trachoma has a distinctive pathology, encompassing repeated rounds of conjunctivitis, which can lead to chronic inflammation, corneal scarring and blindness. It has long been that while strains that cause UGT infections are essentially all able to cause conjunctivitis, the strains that cause trachoma are rarely associated with UGT infection. Previous genetic studies have shown that the trachoma strains form a single evolutionary lineage within the C. trachomatis species. This presentation will encompass recent advances in the understanding of the evolutionary structure and dynamics of C. trachomatis . Much of the work described was directed towards understanding better how service providers should respond to instances in which UGT specimens from young children are found to be C. trachomatis positive. While this is regarded as indicative of sexual abuse, a conceivable mechanism by which this can arise is autoinoculation from an ocular C. trachomatis infection. This is particularly relevant to remote northern and central Australia, where trachoma still exists, and where the extent of child sexual abuse is contentious and politically loaded. Understanding the strains associated with trachoma in Australia could potentially underpin procedures for determining whether or not C. trachomatis in a paediatric UGT specimen is derived from an ocular infection. Genome sequences of historic trachoma associated C. trachoma isolates from Northern Australia will be presented. The results do not support the established model of a single trachoma lineage. While the isolates possessed alleles of the ompA gene previously associated with trachoma strains, these appeared to be recombined into multiple non-trachoma-associated lineages. Furthermore, there was evidence for acquisition of of pmpEFGH alleles similar to those found in trachoma lineages. It was concluded that ompA and pmpEFGH may be functionally associated with trachoma pathology. Disclosure of interest statement Much of the work presented was funded by the NHMRC project grants 1004123 and 1060768. Phil Giffard declares no other interests.