The microbiological signature of human cutaneous leishmaniasis lesions exhibits restricted bacterial diversity compared to healthy skin

Abstract

Localised cutaneous leishmaniasis (LCL) is the most common form of cutaneous leishmaniasis characterised by single or multiple painless chronic ulcers, which commonly presents with secondary bacterial infection. Previous culture-based studies have found staphylococci, streptococci, and opportunistic pathogenic bacteria in LCL lesions, but there have been no comparisons to normal skin. In addition, this approach has strong bias for determining bacterial composition. The present study tested the hypothesis that bacterial communities in LCL lesions differ from those found on healthy skin (HS). Using a high throughput amplicon sequencing approach, which allows for better populational evaluation due to greater depth coverage and the Quantitative Insights Into Microbial Ecology pipeline, we compared the microbiological signature of LCL lesions with that of contralateral HS from the same individuals.Streptococcus, Staphylococcus,Fusobacterium and other strict or facultative anaerobic bacteria composed the LCL microbiome. Aerobic and facultative anaerobic bacteria found in HS, including environmental bacteria, were significantly decreased in LCL lesions (p < 0.01). This paper presents the first comprehensive microbiome identification from LCL lesions with next generation sequence methodology and shows a marked reduction of bacterial diversity in the lesions.

Meta Analysis of Skin Microbiome: New Link between Skin Microbiota Diversity and Skin Health with Proposal to Use This as a Future Mechanism to Determine Whether Cosmetic Products Damage the Skin

“…We note, interestingly, that the diversity of LCL lesioned skin in the Brazilian agricultural communities [76] is well below that of any healthy community, indicating that there may be a minimum diversity level for what could be defined as "healthy skin". This is a crucial observation for our purposes as it allows us to hypothesise a simple mechanism for determining skin health and thus its likelihood to prevent or promote disease: if human skin microbiota diversity falls anywhere We note, interestingly, that the diversity of LCL lesioned skin in the Brazilian agricultural communities [76] is well below that of any healthy community, indicating that there may be a minimum diversity level for what could be defined as "healthy skin".…”

“…This is a crucial observation for our purposes as it allows us to hypothesise a simple mechanism for determining skin health and thus its likelihood to prevent or promote disease: if human skin microbiota diversity falls anywhere We note, interestingly, that the diversity of LCL lesioned skin in the Brazilian agricultural communities [76] is well below that of any healthy community, indicating that there may be a minimum diversity level for what could be defined as "healthy skin". This is a crucial observation for our purposes as it allows us to hypothesise a simple mechanism for determining skin health and thus its likelihood to prevent or promote disease: if human skin microbiota diversity falls anywhere around or under the "unhealthy" lines (marked as dashes in Figure 6), then we can predict that it is damaged and likely to be either currently diseased or certainly open to immune related allergic conditions or attack by pathogens.…”

“…We use a study of healthy versus localised cutaneous leishmaniasis (LCL) afflicted skin in an agricultural community in Brazil [76], healthy diabetic skin compared to subjects with wounds in the USA [77], and further evidence using other species such as dogs and mice [28,78].…”

“…Individuals with LCL had their skin microbiome (the full length of the forearm was swabbed) tested against those in the same village who had "healthy" skin [76]. LCL results in chronic, painless ulcers progressing commonly to secondary bacterial infections.…”

“…We need to be able to match each dataset together, so we created the following formula to approximate the diversity curves from the studies described in Section 2.1.2 [75], Section 2.1.3 [76] and Section 2.1.4 [77]:…”