A Novel Alkaliphilic Streptomyces Inhibits ESKAPE Pathogens

Abstract

In an effort to stem the rising tide of multi-resistant bacteria, researchers have turned to niche environments in the hope of discovering new varieties of antibiotics. We investigated an ethnopharmacological (cure) from an alkaline/radon soil in the area of Boho, in the Fermanagh Scarplands (N. Ireland) for the presence of Streptomyces, a well-known producer of antibiotics. From this soil we isolated a novel (closest relative 57% of genome relatedness) Streptomyces sp. capable of growth at high alkaline pH (10.5) and tolerant of gamma radiation to 4 kGy. Genomic sequencing identified many alkaline tolerance (antiporter/multi-resistance) genes compared to S. coelicolor M145 (at 3:1), hence we designated the strain Streptomyces sp. myrophorea, isolate McG1, from the Greek, myro (fragrance) and phorea (porter/carrier). In vitro tests demonstrated the ability of the Streptomyces sp. myrophorea, isolate McG1 to inhibit the growth of many strains of ESKAPE pathogens; most notably carbapenem-resistant Acinetobacter baumannii (a critical pathogen on the WHO priority list of antibiotic-resistant bacteria), vancomycin-resistant Enterococcus faecium, and methicillin-resistant Staphylococcus aureus (both listed as high priority pathogens). Further in silico prediction of antimicrobial potential of Streptomyces sp. myrophorea, isolate McG1 by anti-SMASH and RAST software identified many secondary metabolite and toxicity resistance gene clusters (45 and 27, respectively) as well as many antibiotic resistance genes potentially related to antibiotic production. Follow-up in vitro tests show that the Streptomyces sp. myrophorea, isolate McG1 was resistant to 28 out of 36 clinical antibiotics. Although not a comprehensive analysis, we think that some of the Boho soils’ reputed curative properties may be linked to the ability of Streptomyces sp. myrophorea, isolate McG1 to inhibit ESKAPE pathogens. More importantly, further analysis may elucidate other key components that could alleviate the tide of multi-resistant nosocomial infections.

Antimicrobial Activity of Clinically Isolated Bacterial Species Against Staphylococcus aureus

“…In contrast contact-independent growth inhibition is typically mediated by toxic compounds that are synthesized and then secreted by the inhibitory species as a means to kill/prevent the growth of a competitor; no cell-to-cell contact between the two species is required. This approach is a common mechanism that is used by various microbes across multiple ecological niches and these compounds can include bacteriocins, secondary metabolites, and other small molecules (Zipperer et al, 2016;Terra et al, 2018). Finally, it is worth noting that some antagonistic interactions are more complex and can involve both contact-independent and dependent mechanisms.…”

Identification and Testing of Antidermatophytic Oxaborole-6-Benzene Sulphonamide Derivative (OXBS) from Streptomyces atrovirens KM192347 Isolated from Soil

“…For instance, Genus Kitasatophora was reassigned as sister taxon to Genus Streptomyces or a lineage that originated from Streptomyces species [32]. Similar recent studies also used these sequence of 16S rRNA gene as a successful way for the identification of actinomycetes [4,33].…”

“…Streptomyces spp. has recently been shown to produce antibiotics when stressed by alkaliphilic environment [4]. The antifungal activity of Streptomyces spp.…”

Genome Mining Revealed a High Biosynthetic Potential for Antifungal Streptomyces sp. S-2 Isolated from Black Soot

“…Streptomyces sp. myrophorea McG1, which has antibacterial activity, has been shown to be resistant to a number of antibiotics, including those targeting protein synthesis [27]. This might suggest a lack of antibacterial activity in Streptomyces sp.…”

“…S-2. However, in that study, the resistance to some antibiotics of the McG1 strain was established after 6 days of culture, and the test was performed using different methodology [27]. The high number of BGCs, as well as the prevalence of NRPS and T1PKS clusters, distinguish the S-2 strain from other Streptomyces strains, especially considering its relatively small genome size.…”