Evaluation of Hand Bioburden and Genomic Features of Staphylococcus spp. Following Handwashing Practice Among Aboriginal Schoolchildren in Rural Malaysia.

Abstract

Data integrating hand bioburden and antimicrobial resistance with genomic characterisation among Aboriginal schoolchildren remains limited. Hand imprint samples were collected from 60 Orang Asli schoolchildren in Kelantan, Malaysia, immediately before and after handwashing, three months after a one-day educational intervention. Selected pre-handwashing Staphylococcus isolates underwent antimicrobial susceptibility testing, and four multidrug-resistant Staphylococcus arlettae isolates underwent whole-genome sequencing. Mean left-hand and median right-hand bioburden, expressed as log₁₀ colony forming units(CFUs)/plate, were lower after handwashing, but neither comparison was statistically significant after Holm adjustment. Escherichia coli/Shigella complex recovery decreased from 21/60 participants (35.0%) to none (Holm-adjusted p < 0.001). Resistance to penicillin, fusidic acid and erythromycin was frequent, while most isolates were susceptible to linezolid and rifampicin. Sequencing identified msr(A) and dfrG in all four isolates, mph(C) in three, partial arginine catabolic mobile element (ACME)-associated sequences in all four, and the rep24c replicon belonging to the replication initiation protein family RepA_N in two. Genotype-phenotype concordance was partial: ResFinder detected no corresponding acquired resistance determinants for several resistant or intermediate phenotypes. These exploratory findings describe immediate bacterial recovery and selected isolates' resistance and genomic features; they do not establish the effectiveness of the earlier educational intervention.