First Description of the Composition and the Functional Capabilities of the Skin Microbial Community Accompanying Severe Scabies Infestation in Humans

Abstract

Epidemiological studies link Sarcoptes scabiei infection and impetigo. Scabies mites can promote Streptococcus pyogenes (Group A Streptococcus) and Staphylococcus aureus infections by breaching the skin barrier and excreting molecules that inhibit host innate immune responses. However, little is known about the composition and the function of the scabies-associated microbiota. Here, high-throughput whole-metagenome sequencing was used to explore the scabies-associated microbiome. Scabies mites including their immediate microenvironments were isolated from two patients with severe scabies in Northern Australia. Two ~45–50 million paired-end reads Illumina libraries were generated of which ~2 (5.1%) and 0.7 million (1.3%) microbial reads were filtered out by mapping to human (hg19) and mite draft genomes. Taxonomic profiling revealed a microbial community dominated by the phylum Firmicutes (A: 79% and B: 59%) and genera that comprise Streptococcus, Staphylococcus, Acinetobacter, and Corynebacterium. Assembly of the metagenome reads resulted in genome bins representing reference genomes of Acinetobacter baumannii, Streptococcus dysgalactiae (Group C/G), Proteus mirablis and Staphylococcus aureus. The contigs contained genes relevant to pathogenicity and antibiotics resistance. Confocal microscopy of a patient skin sample confirmed A. baumannii, Streptococci and S. aureus in scabies mite gut and faeces and the surrounding skin. The study provides fundamental evidence for the association of opportunistic pathogens with scabies infection.

Investigating the Antibacterial Properties of Prospective Scabicides

“…Both of these drugs are neuroinhibitors and target only the motile stages of the parasite’s lifecycle, which necessitates repeat treatments [ 3 ]. Consistent with other single-target agents, variable scabicidal efficacy and drug tolerability by the parasite have been observed for these drugs in recent years [ 4 ], clinical resistance to ivermectin and anecdotal evidence of resistance to permethrin have been reported [ 5 , 6 ] and the link to severe downstream complications due to bacterial co-infections has become more apparent [ 7 , 8 , 9 , 10 ]. These issues have renewed the focus on the development of new-generation scabicides.…”

Sarcoptic mange changes bacterial and fungal microbiota of bare-nosed wombats (Vombatus ursinus)

“…and especially Staphylococcus spp. match patterns in humans [ 12 , 13 ], North American canids [ 14 ], pigs [ 15 ], and Iberian ibex [ 16 , 17 ]. Staphylococcus was present on almost all BNWs with moderate or severe mange and only in one sample in healthy wombats, suggesting an increased colonisation of Staphylococcus with disease.…”

“…(although missing in Iberian ibex). Human [ 12 , 13 ], Iberian ibex [ 16 , 17 ], and pig [ 15 ] studies all identified Staphylococcus aureus with severe disease. Additionally, an Iberian ibex study [ 16 ] identified Staphylococcus warneri as well as Staphylococcus chromogenes as potential pathogenic bacteria with sarcoptic mange.…”

“…The variation in Staphylococcus species identified could reflect host or environmental differences, most likely the former. Neither the N. American canid study [ 14 ] nor the pig study [ 15 ] described a change or presence of Pseudomonas aeruginosa in line with what was observed in humans [ 13 ] and Iberian ibex [ 16 ]. Our study provided evidence of continuous presence of Pseudomonas , but without fluctuations in disease status, and we were unable to identify the species (full overview is listed in Table 1 ).…”

“…and S. sciuri Staphylococcus aureus Staphylococcus spp. and S. pseudintermedius Staphylococcus aureus and Staphylococcus chromogenes Staphylococcu s aureus [ 16 , 17 ] and Staphylococcus warneri [ 16 ] Pseudomonas aeruginosa and Group A Streptococcus , [ 13 ] a Pseudomonas aeruginosa [ 16 ] a Brachybacterium spp. Brevibacterium spp.…”