Review of human hand microbiome research

Abstract

Recent advances have increased our understanding of the human microbiome, including the skin microbiome. Despite the importance of the hands as a vector for infection transmission, there have been no comprehensive reviews of recent advances in hand microbiome research or overviews of the factors that influence the composition of the hand microbiome. A comprehensive and systematic database search was conducted for skin microbiome-related articles published from January 1, 2008 to April 1, 2015. Only primary research articles that used culture-independent, whole community analysis methods to study the healthy hand skin microbiome were included. Eighteen articles were identified containing hand microbiome data. Most focused on bacteria, with relatively little reported on fungi, viruses, and protozoa. Bacteria from four phyla were found across all studies of the hand microbiome (most to least relative abundance): Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes. Key factors that impacted the hand microbiome composition included temporal and biogeographical dynamics, as well as intrinsic (age, gender) and extrinsic (product use, cohabitants, pet-ownership) variables. There was more temporal variability in the composition of the hand microbiome than in other body sites, making identification of the "normal" microbiome of the hands challenging. The microbiome of the hands is in constant flux as the hands are a critical vector for transmitting microorganisms between people, pets, inanimate objects and our environments. Future studies need to resolve methodological influences on results, and further investigate factors which alter the hand microbiome including the impact of products applied to hands. Increased understanding of the hand microbiome and the skin microbiome in general, will open the door to product development for disease prevention and treatment, and may lead to other applications, including novel diagnostic and forensic approaches.

The Core and Seasonal Microbiota of Raw Bovine Milk in Tanker Trucks and the Impact of Transfer to a Milk Processing Facility

“…Although there are myriad possible explanations for the increased species richness, this finding coincided with a significant increase in the relative proportion of bacteria in the phylum Actinobacteria . Because the Actinobacteria species identified here are associated with soil (38–41), it is possible that the increase in species richness observed in spring was due to seasonal changes, such as increased precipitation, promoting growth of Actinobacteria in the soil and transfer to the cow udder. Notably, these results were not necessarily due to increased access to the pasture in the spring, as pasture rates are low for the California Central Valley (data not shown).…”

A systematic literature review of the human skin microbiome as biomarker for dermatological drug development

“…Several reviews have described the role and impact of skin microbiome on disease 17, 18, 19, 20, 21, 22. However, to date, no structured review has been conducted to evaluate the feasibility, suitability and potential use of the skin microbiome as biomarker for early phase clinical drug development.…”

Dirty Money: A Matter of Bacterial Survival, Adherence, and Toxicity

“…Both banknotes and coins are predominantly handled by multiple humans through touch. The overall human skin microbiome is arguably dominated by four main bacterial phyla: Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes [13,14,15], while the hand microbiome is dominated by the Proteobacteria and Bacteroidetes [13,15]. The microbiota of hands can be divided into two groups: firstly, there are the resident microorganisms, which represent a relatively fixed group of microorganisms whose makeup changes very little and tend to recover rapidly following perturbation.…”

“…Secondly, there is a group of transient microorganisms that rarely establish a permanent residency on the skin but might exist because of external environmental exposures that might persist for a few hours up to a couple of days [15]. We therefore argue that the most likely source of the microorganisms on currency originates from humans [13,14,15,16,17,18] and could be considered as a heterogeneous microbiome.…”