Distinct microbiome profiles and biofilms in Leishmania donovani-driven cutaneous leishmaniasis wounds

The endemic strain of Leishmania donovani in Sri Lanka causes cutaneous leishmaniasis (CL) rather than more common visceral form. We have visualized biofilms and profiled the microbiome of lesions and unaffected skin in thirty-nine CL patients. Twenty-four lesions (61.5%) were biofilm-positive according to fluorescence in situ hybridization. Biopsies of biofilm-positive lesions were dominated by Pseudomonas, class Bacilli and Enterobacteriaceae and distinguished by significantly lower community evenness. Higher relative abundance of a class Bacilli OTU was detected in wound swabs versus contralateral skin. Wound swabs and biopsies had significantly distinct microbiome profiles and lower diversity compared to unaffected skin. Greater abundances of potentially pathogenic organisms were observed in wet ulcers, lesions with high parasite loads and large wounds. In summary, more than half of L. donovani associated CL wounds harboured biofilms and the wounds exhibited a distinct, less diverse, microbiome than unaffected skin.

Determining the hierarchical order by which the variables of sampling period, dust outbreak occurrence, and sampling location can shape the airborne bacterial communities in the Mediterranean basin

A next-generation sequencing (NGS)-based taxonomic analysis was carried out on airborne bacteria sampled at ground level in two periods (May and September) and two opposite locations on the north–south axis of the island of Sardinia. Located in a central position of the Mediterranean basin, Sardinia constitutes a suitable outpost for revealing possible immigration of bacterial taxa during transcontinental particle discharge between Africa and Europe. With the aim of verifying relative effects of dust outbreaks, sampling period, and sampling site on the airborne bacterial community composition, we compared air collected during dust-carrying meteorological events to that coming from wind regimes not associated with long-distance particle lifting. Results indicated that (a) higher microbial diversity and richness (118 vs. 65 orders) and increased community evenness were observed in the campaign carried out in September in comparison to the one in May, irrespective of the place of collection and of the presence or absence of dust outbreaks; (b) during the period of standard wind regimes without transcontinental outbreaks, a synchronous concerted turnover of bacterial communities across distant locations of the same island, accompanied as mentioned by a parallel rise in bacterial diversity and community evenness, appears to have occurred; (c) changes in wind provenance could transiently change community composition in the locality placed on the coast facing the incoming wind but not in the one located at the opposite side of the island, and for this reason the community changes brought from dust outbreaks of African origin are observed only in the sampling station exposed to the south; (d) the same winds, once proceeding over land, appear to uplift bacteria belonging to a common core already present over the region, which dilute or replace those that were associated with the air coming from the sea or conveyed by the dust particulates, explaining the two prior points; and (e) the hierarchy of the variables tested in determining bacterial assemblages composition results is as follows: sampling period≫ongoing meteorological events>sampling location within the island.

Characterisation of Early Microbial Colonisers within the Spiral Colon of Pre- and Post-Natal Piglets

Initial enteric microbial colonisation influences animal health and disease, hence an understanding of the first microbial colonisers within the piglet is important. The spiral colon of piglets that were stillborn (n = 20), born-alive (n = 10), and born alive and had sucked (n = 9) were collected from 28 sows to investigate whether initial microbial colonisation occurs pre- or post-partum and how it develops during the first 24 h post-partum. To examine this, DNA was extracted and 16S rRNA amplicon analysis was performed to allow analysis of microbial communities. The results indicate that microbial colonisation of the spiral colon had occurred in stillborn pigs, suggesting microbial exposure prior to birth. Alpha diversity metrics indicated that the number of taxa and community richness were higher in piglets that sucked (p < 0.001) and community evenness was lower in stillborns in comparison to born-alive (p < 0.001) but was not affected by colostrum consumption (p < 0.001). Additionally, when compared with stillborn piglets, the bacteria colonising the spiral colon during the first 24 h post-partum included the potentially pathogenic bacteria Escherichia coli, Clostridium perfringens and Clostridium celatum, and potentially beneficial bacteria Lactobacillus reutueri and Faecalibacterium prausnitzii. The relative presence of Archaea was high in stillborn piglets but decreased with post-natal environmental exposure. It is evident that stillborn piglets have bacteria present within their spiral colon, however further studies are needed in order to determine the time at which colonisation is initiated and the mechanisms determining how colonisation occurs. Additionally, as expected, the immediate post-natal environment largely influences the microorganisms colonising, while colostrum consumption further contributes to the microbial community enrichment.

Determining the hierarchical order by which the variables of sampling season, dust outbreaks occurrence, and sampling location, can shape the airborne bacterial communities in the Mediterranean basin

An NGS-based taxonomic analysis was carried out on airborne bacteria sampled at ground level in two periods (May and September) and two opposite localities on the North-South axis of the Sardinia Island. Located in a central position of the Mediterranean basin, Sardinia constitutes a suitable outpost to reveal possible immigration of bacterial taxa during transcontinental particle discharge between Africa and Europe. With the aim of verifying relative effects of dust outbreaks, sampling period and sampling site, on the airborne bacterial community composition, we compared air collected during dust-carrying meteorological events to that coming from wind regimes not associated to long-distance particle lifting. Results indicated that: (a) a higher microbial diversity (118 orders vs 65) and increased community evenness were observed in the campaign carried out in September in comparison to the one in May, irrespective of the place of collection and of the presence or absence of dust outbreaks. (b) During the period of standard wind regimes without transcontinental outbreaks a synchronous, concerted succession of bacterial communities across distant locations of the same island, accompanied as mentioned by a parallel rise in bacterial diversity and community evenness appears to have occurred. (c) changes in wind provenance could transiently change community composition in the locality placed on the coast facing the incoming wind, but not in the one located at the opposite side of the island; for this reason the community changes brought from dust outbreaks of African origin are observed only in the sampling station exposed to south; (d) the same winds, once proceeding over land appear to uplift bacteria belonging to a common core already present over the region, which dilute or replace those that were associated with the air coming from the sea or conveyed by the dust particulate, explaining the two prior points. (e) the hierarchy of the variables tested in determining bacterial assemblages composition results: sampling period >> ongoing meteorological events > sampling location within the island.