Exploring microbiota and Healthcare-Associated Infections: from students' awareness and hand-to-surface microbial transfer to patient-centered microbiome analysis (MICROB-ICA Study)

The human body hosts trillions of microorganisms, including bacteria, viruses, fungi, and protozoa, forming a complex ecosystem known as the "human microbiota", which plays a critical role in human health. However, its impact on the development of healthcare-associated infections (HAIs) is still unclear. HAIs are infectious diseases that manifest at least 48 hours after hospital admission. In this context, my PhD project, named “MICROB-ICA” study, aimed to deepen knowledge on HAIs through a multidimensional approach, combining innovative research methodologies to identify targeted prevention strategies. First of all, a survey addressed to students of the University of Padua was administered with the purpose to explore knowledge, awareness, and perception of the topic of HAIs. The results showed that several factors, some modifiable, influenced knowledge on the topic, suggesting the opportunity for targeted information interventions based on study academic paths. Subsequently, the experimental phase included the characterization of microbiological profiles related to the skin before, and skin and oral cavity later, through Next-Generation Sequencing (NGS) analysis of the bacterial 16S rRNA, followed by bioinformatic and statistical analyses with Qiime2 and R software. In particular, in the "Touch Microbiota Study" the composition of the skin microbiota released by healthy volunteers on common healthcare-related surfaces and the effect of hand washing on microbial adhesion were studied. The results highlighted a differential persistence of HAIs-related and opportunistic bacteria, with a prevalence of Gram-positive bacteria on glass surfaces and Gram-negative on laminated table surfaces, underlining the importance of specific hygienic surveillance protocols for different surfaces. In the last phase of the project (“Patients Microbiota Study”) skin and oral microbial profiles of patients undergoing vascular endografts implantation were analysed, identifying microbiological biomarkers associated with the development of infections. In oral samples, a reduction in microbial diversity was associated with patients who developed HAIs, whereas in skin samples, an increase in microbial diversity was observed in the same group. Furthermore, specific taxa, such as Firmicutes D phylum, Staphylococcus, Haemophilus, Prevotella denticola, and Streptococcus mutans, emerged as potential indicators of HAIs susceptibility. Overall, our study provided indications about the need to improve the formative plan of our university system, with the aim to better sensitize young generations about the public issue of HAIs in a horizon of prevention. Furthermore, our data highlighted the importance of implementing new target cleaning and hygiene practices within healthcare facilities to prevent the spread of HAIs but, above all, our investigation enabled to shed light about the possible predictive role related to the development of HAIs of some microbiological biomarkers in patients undergoing surgical interventions.