Table 1.

Summary of recent 16S rRNA sequencing-based human skin bacterial microbiome studies in healthy subjects and in patients with skin disorders

Health status	Skin site sampled	Study Conclusions	Reference
Healthy	Outer ear canal	24 subjects (adult, children from 3 families). Sanger sequencing of representative RFLP types. Sex and age affected bacterial diversity. Two most prevalent sequences were bacteria known to cause middle ear infections, suggesting outer ear canal is possible reservoir.	[36]
Healthy	Forehead	5 subjects. Sanger sequencing with concurrent bacterial cultures. Sequencing showed greater bacterial diversity than cultures and identified novel bacteria.	[37]
Healthy	Forearms	6 subjects (4 re-sampled 8-10 months later). Sanger sequencing with concurrent bacterial cultures. 16% of species identified via sequencing were cultured from same specimens. Right/left samples were more similar than follow-up samples from same individual.	[39]
Healthy	Volar (inner) forearms, antecubital fossa (front of elbows)	5 subjects. Sanger sequencing. 3 sampling methods (swab, scrape, punch biopsy) showed dominant bacterial phyla similarly represented by all methods.	[38]
Healthy	Palms	51 subjects. Pyrosequencing. Bacterial species on right/left palms on same and different individuals had low similarity. Handedness, time from washing, and an individual’s sex were associated with similarly structured bacterial communities.	[37]
Healthy	Glabella (forehead), alar crease (side of nose), external auditory canal (outer ear canal), occiput (back of scalp), manubrium (upper chest), back, nares (anterior nose), axilla (armpit), antecubital fossae (front of elbow), fingerweb, inguinal crease (side of groin), gluteal crease (uppermost part of fold between buttocks), popliteal crease (back of knee), heel, umbilicus (navel), forearm, palm, buttock	10 subjects (5 resampled). Sanger sequencing. 20 sites selected based on sites of predilection of skin diseases. Skin physiological characteristics (oily, moist, dry) affected composition of bacterial communities. Interpersonal variation and stability over time varied by site.	[43]
Healthy	Index fingers, palms, volar (inner) forearm, forehead, external nose, external ears (pinna), hair, armpits (axilla), soles of feet, navel (umbilicus), backs of knees (popliteal fossae), nostrils (nares), external auditory canal (outer ear canal)	9 subjects (resampled up to 4 times). Pyrosequencing. Up to 18 skin sites sampled along with gut and oral sites. Bacterial composition depended on site and varied by individual sampled.	[41]
Healthy	Fingers, axilla (armpits)	Up to 9 subjects (and personal computer equipment) Pyrosequencing. Bacterial composition of each subject was similar to that found on personal computer equipment.	[27]
Healthy	Ventral forearms (newborns and mothers), forehead (newborns)	10 newborns, 9 mothers (4 vaginal deliveries, 5 Cesarean sections). Pyrosequencing. Newborn bacterial communities were homogeneous across skin sites and determined by mode of delivery	[42]
Acne	Facial hair follicles (patients and controls), skin (2 patients)	5 patients, 3 controls. Sanger sequencing. Hair follicle bacterial composition showed limited diversity in patients and only one species in controls	[44]
Chronic wounds	Decubitus/pressure (7), neuropathic/decreased nerve sensation (7), venous stasis (3), post-surgical (3), other (4) ulcers	24 patients (12 with diabetes, 14 received antibiotics). Wound bed curette samples. Pyrosequencing with concurrent cultures. Bacterial composition was more diverse with sequencing than cultures and influenced by antibiotic exposure.	[49]
Chronic wounds	Venous leg ulcers	8 ulcers (40 total samples). Wound bed curette samples. Pyrosequencing. Bacterial composition showed topographical differences within large ulcers.	[58]
Chronic wounds	Diabetic wounds, intact skin	23 paired samples. Debridement and skin swab samples. Pyrosequencing. Intact skin had greater bacterial diversity yet lower levels of known opportunistic wound pathogens than wound samples.	[56]
Psoriasis	Psoriasis plaques (affected, unaffected)	6 patients. Sanger sequencing. Greater bacterial diversity observed in psoriasis lesions than unaffected skin in patients and controls.	[47]