Background Major challenges in the management of infectious diseases include treatment failure due to antimicrobial resistance (AMR) and the lack of a reliable test of cure (TOC). Whilst culture is a trusted method it is slow, and with the widespread use of nucleic acid amplification tests (NAATs), many labs no longer retain culture capabilities. NAATs can assess AMR by detecting microbial mutations associated with resistance; however, this approach requires knowledge of the molecular mechanism(s), and as new mutations emerge, tests need to be reconfigured. Uses of NAATs for TOC is problematic since residual DNA and RNA have been reported following effective therapy. The VITA method provides a new tool which can overcome current drawbacks.

Methods The VITA Index is the ratio of the number of copies of a gene and its associated transcripts to those of a non-transcribed region of DNA. It provides a relative measure of active transcription regardless of the quality/quantity of specimen. The approach has several applications. Firstly, following addition of antibiotic to a specimen, e.g. for 5 min/37°C or 15 min/room temperature, Total Nucleic Acid can be amplified by VITA RT-PCR. Comparison of the VITA indices ± drug will relate to antibiotic resistance or sensitivity. VITA RT-PCR can later provide a TOC, where VITA indices of a specimen can fall either above or below a predetermined threshold, indicating a viable or cleared infection respectively.

Results Both sensitivity and resistance to different antibiotics has been demonstrated in vitro on Chlamydia trachomatis, with significant decreases in VITA in the presence of drug in sensitive (p<0.05), but not in resistant strains. Further, urine obtained from a patient post-treatment was analysed, and consistent with clinical evidence of ongoing infection, the VITA Index indicated viable chlamydia.

Conclusion In conclusion, VITA provides a powerful new approach for rapid determination of AMR and TOC.

Disclosure No significant relationships.