Kisameet Glacial Clay: an Unexpected Source of Bacterial Diversity

Svensson, Sarah L.; Behroozian, Shekooh; Xu, Wanjing; Surette, Michael G.; Li, Loretta Y.; Davies, Julian

doi:10.1128/mbio.00590-17

Cited by 21 publications

(28 citation statements)

References 68 publications

(89 reference statements)

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“…Exchangeable metal ions have been reported to be responsible for the activity of some antibacterial clays (35)(36)(37). We and others have previously found that the mineralogical composition and chemical properties of KC differ from those of other known natural antibacterial clay minerals (43,46,52). Next, we investigated if the exchangeable/soluble fraction of the clay might be involved in KC activity.…”

Section: Resultsmentioning

confidence: 96%

“…Our previous studies showed that aqueous suspensions of KC exhibit potent antibacterial activity against the clinically important ESKAPE pathogens in vitro (45). We also characterized the geochemical and microbiological features across the KC deposit to obtain insight into what might make the clay active (46). This revealed a surprising level of bacterial species richness and prevalence of iron bacteria such as Gallionella species near the surface of the deposit, provided molecular evidence for taxa that include medically or economically important bacteria such as Actinomycetes, and in general highlighted the complexity and diversity of the KC deposit.…”

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confidence: 99%

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Broad-Spectrum Antimicrobial and Antibiofilm Activity of a Natural Clay Mineral from British Columbia, Canada

Behroozian

Svensson

et al. 2020

mBio

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Worldwide increases in antibiotic resistance and the dearth of new antibiotics have created a global crisis in the treatment of infectious diseases. These concerns highlight the pressing need for novel antimicrobial agents. Natural clay minerals have a long history of therapeutic and biomedical applications and have lately received specific attention for their potent antimicrobial properties. In particular, Kisameet clay (KC) has strong antibacterial activity against a variety of multidrug-resistant (MDR) bacterial pathogens in vitro. Here, we have extended the known spectrum of activity of KC by demonstrating its efficacy against two major fungal pathogens, Candida albicans and Cryptococcus neoformans. In addition, KC also exhibits potent activity against the opportunistic bacterial pathogen Mycobacterium marinum, a model organism for M. ulcerans infection. Moreover, aqueous KC leachates (KC-L) exhibited broad-spectrum antibacterial activity, eradicated Gram-negative and Gram-positive biofilms, and prevented their formation. The mechanism(s) underlying KC antibacterial activity appears to be complex. Adjusting KC-L to neutral pH rendered it inactive, indicating a contribution of pH, although low pH alone was insufficient for its antibacterial activity. Treatment of KC minerals with cation-chelating agents such as EDTA, 2,2′-bipyridyl, and deferoxamine reduced the antibacterial activity, while supplementation of KC-L with these chelating agents eliminated the inhibitory activity. Together, the data suggest a positive role for divalent and trivalent cations, including iron and aluminum, in bacterial inhibition by KC. Collectively, these studies demonstrate the range of KC bioactivity and provide a better understanding of the mechanism underlying its antibacterial effects. IMPORTANCE The escalating emergence of multidrug-resistant (MDR) bacteria, together with the paucity of novel antimicrobial agents in antibiotic development, is recognized as a worldwide public health crisis. Kisameet clay (KC), found in British Columbia (BC), Canada, is a clay mineral with a long history of therapeutic applications among people of the First Nations. We previously reported the antibacterial activity of KC against a group of MDR clinical pathogens. Here, we demonstrate its activity against two major human-pathogenic fungal species, as well as against bacterial biofilms, which underlie many recalcitrant bacterial infections. In these studies, we also identified several geochemical characteristics of KC, such as metal ions and low pH, which are involved in its antibacterial activity. These findings provide a better understanding of the components of KC antibacterial activity and a basis for developing defined preparations of this clay mineral for therapeutic applications.

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Section: Resultsmentioning

confidence: 96%

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confidence: 99%

Broad-Spectrum Antimicrobial and Antibiofilm Activity of a Natural Clay Mineral from British Columbia, Canada

Behroozian

Svensson

et al. 2020

mBio

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“…Unlike Streptomyces discovered from the golden age of antibiotic discovery in the mid-20th century, traditional medicine soils are specific in their locations such as the Boho clay, or in their type such as glacial clay from Canada [52,53]. Clay, which has long been thought to be therapeutic in itself, is also home to a diverse array of Streptomyces [22,[52][53][54]. Traditional glacial clay from Kisameet Bay in Canada has been used for millennia by the Heiltsuk people against skin infections [52].…”

Section: Streptomyces From Traditional Soil-based Medicinementioning

confidence: 99%

“…It is quite typical to find multiple species of Streptomyces in traditional medical preparations such as soil or moonmilk [50,54,64]. Now, it has been discovered that competition and collaboration between Streptomyces and other species can also awaken silent antibiotic-synthesis clusters [65].…”

Section: Co-cultivationmentioning

confidence: 99%

Streptomyces from traditional medicine: sources of new innovations in antibiotic discovery

Quinn

Banat

Abdelhameed

et al. 2020

Journal of Medical Microbiology

150

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Given the increased reporting of multi-resistant bacteria and the shortage of newly approved medicines, researchers have been looking towards extreme and unusual environments as a new source of antibiotics. Streptomyces currently provides many of the world’s clinical antibiotics, so it comes as no surprise that these bacteria have recently been isolated from traditional medicine. Given the wide array of traditional medicines, it is hoped that these discoveries can provide the much sought after core structure diversity that will be required of a new generation of antibiotics. This review discusses the contribution of Streptomyces to antibiotics and the potential of newly discovered species in traditional medicine. We also explore how knowledge of traditional medicines can aid current initiatives in sourcing new and chemically diverse antibiotics.

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“…Analyses of different clay layers of coastal subseafloor sediments from Okhotsk sea identified a variety of bacteria and archaea, such as green non-sulfur bacteria and deep sea archaeal group (Inagaki et al, 2003). Different groups of bacteria were found in the Opalinus clay rock from Mont Terri, Switzerland and Kisameet Glacial clay from British Columbia, Canada, whose functions range from CO 2 fixation to sulfate reduction (Bagnoud et al, 2016a,b;Svensson et al, 2017). Thus, a phylogenetically and physiologically diverse groups of bacteria and archaea are associated with subsurface clay layers.…”

Section: Introductionmentioning

confidence: 99%

Bacterial and Archaeal Diversity and Abundance in Shallow Subsurface Clay Sediments at Jianghan Plain, China

Song

Jiang

et al. 2020

Front. Microbiol.

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Clay layers are common in subsurface where microbial activities play an important role in impacting the biogeochemical properties of adjacent aquifers. In this study, we analyzed the community structure and abundance of bacteria and archaea in response to geochemical properties of six clay sediments at different depths in a borehole (112 • 34 0 E, 30 • 36 21 N) of Jianghan Plain (JHP), China. Our results suggested that the top two clay layers were oxic, while the remaining bottom four clay layers were anoxic. Both high-throughput sequencing and qPCR of 16S rRNA gene showed relatively high abundance of archaea (up to 60%) in three of the anoxic clay layers. Furthermore, microbial communities in these clay sediments showed distinct vertical stratification, which may be impacted by changes in concentrations of sulfate, HClextractable Fe 2+ and total organic carbon (TOC) in the sediments. In the upper two oxic clay layers, identification of phyla Thaumarchaeota (11.2%) and Nitrosporales (1.2%) implied nitrification in these layers. In the two anoxic clay layers beneath the oxic zone, high abundances of Anaeromyxobacter, Chloroflexi bacterium RBG 16_58_14 and Deltaproteobacteria, suggested the reductions of nitrate, iron and sulfate. Remarkably, a significant portion of Bathyarchaeota (∼25%) inhabited in the bottom two anoxic clay layers, which may indicate archaeal anaerobic degradation of TOC by these organisms. The results of this study provide the first systematic understandings of microbial activities in subsurface clay layers at JHP, which may help develop microorganism-based solutions for mitigating subsurface contaminations.

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Kisameet Glacial Clay: an Unexpected Source of Bacterial Diversity

Cited by 21 publications

References 68 publications

Broad-Spectrum Antimicrobial and Antibiofilm Activity of a Natural Clay Mineral from British Columbia, Canada

Broad-Spectrum Antimicrobial and Antibiofilm Activity of a Natural Clay Mineral from British Columbia, Canada

Streptomyces from traditional medicine: sources of new innovations in antibiotic discovery

Bacterial and Archaeal Diversity and Abundance in Shallow Subsurface Clay Sediments at Jianghan Plain, China

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