This month we dig into salivary micro-RNA as a liquid biopsy marker in oral cancer, different methods of offering HPV self-sampling kits, and the benefits of probiotics in improving vaginal microbiota composition in post-menopausal women.

• The first study investigates the use of salivary cell-free miRNA as a liquid biopsy marker in cancer. The researchers focused on establishing reproducible methods for saliva manipulation to control pre-analytical variables affecting miRNA stability. Saliva samples from healthy subjects and oral cancer patients were collected using two methods (spit and LolliSponge), and storage conditions were varied. Quantifying the salivary expression level of target miRNAs by qPCR, the study found comparable levels between the two collection methods. MiRNAs remained stable for up to 48 hours at 4 ◦C but showed significant alterations after 96 hours. Mid-term storage at -20 ◦C decreased miRNA stability compared to -80 ◦C. The study concludes that cell-free miRNA in saliva, though slightly affected by collection methods and storage conditions, remains stable for a duration compatible with clinical routine needs.
• In the second study, the US researchers performed a randomized clinical trial to assess the effectiveness of different approaches for offering HPV self-sampling kits to individuals based on their cervical cancer screening history (screening-adherent and currently due, overdue, or unknown). The individuals were stratified to receive usual care, education, direct mail with a self-sampling kit, and an opt-in option. The results also showed that direct-mail self-sampling significantly increased cervical cancer screening by over 14% in individuals who were due or overdue. At the same time, the opt-in approach had minimal impact. The study suggests prioritizing direct-mail outreach for those due or overdue for screening to enhance adherence, while for individuals with unknown screening history, alternative outreach approaches and efforts to document screening history are recommended.
• The third study is a prospective observational clinical trial conducted in Italy, aiming at investigating the benefits of probiotics in improving vaginal well-being and microbiota composition in post-menopausal women. The study enrolled 50 healthy post-menopausal women who took a supplement containing specific probiotic strains for 28 days. Results showed a decrease in menopausal symptoms, with significant improvements in the Vaginal Health Index (VHI) score by 50%, a reduction in inflammatory cytokine levels, and restoration of vaginal microbiota, including an increase in lactobacilli abundance. The study suggests that the tested probiotic strains, previously effective in childbearing-age women, are also beneficial for post-menopausal women, demonstrating improvements in both vaginal well-being and microbiota composition.

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Here are the last papers of 2023 that secured their place in our Microbiology Time:

• In the first paper, researchers from the University of Rome developed a fast protocol for detecting SARS-CoV-2 contaminated surfaces, using a microbial-signature approach based on marker genes found in droplets and other body fluids. The team used available tools, including flocked swab sampling, to design an automated protocol that reduces the time needed to extract nucleic acids from environmental swabs to a quarter. Since equipment for qPCR is widely available and relatively inexpensive today, this approach can be a helpful tool for monitoring the transmission of SARS-CoV-2 or other pathogens in hospitals.
• The second paper is a systematic review of oral swabs as an alternative to sputum for diagnosing pulmonary tuberculosis, published in The Lancet by E. C. Church and colleagues. Analyzing 16 eligible reports (20 studies and 3083 participants) to assess the diagnostic accuracy of oral swabs for diagnosing pulmonary TB in adults and children, the researchers evaluated oral-swabbing sensitivity from 36% to 91% in adults and 5% to 42% in children, while specificity ranged from 66% to 100%. Despite more research being needed to define optimal methods for using oral swabs as a specimen for tuberculosis detection, FLOQSwabs showed increased biomass collection relative to other sampling swabs, which has been linked to higher sensitivity.
• The aim of the third study published by Jacques Schrenzel’s team was to evaluate the clinical performance of PhenoMATRIX and PhenoMATRIX PLUS in screening for methicillin-resistant Staphylococcus aureus from nasal and inguinal/perineal samples using chromogenic media. The automated results were compared to manual readings. In addition, the researchers assessed PhenoMATRIX PLUS for the automatic release of negative results to the LIS and the automatic discharge of negative plates from incubators. The specificities of PhenoMATRIX and PhenoMATRIX PLUS were extremely high (99.1% and 95.2% respectively); All the MRSA-negative specimens analyzed by PhenoMATRIX PLUS were automatically released and sent to the LIS immediately after availability of the culture image on the WASPLab with 100% accuracy and all negative media plates were automatically discarded. The results are clear: PhenoMATRIX PLUS decreases technologists’ time on negative plates, ensuring optimal usage of incubators’ capacity

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