Abstract:The culturable bacterial diversity from Iron Curtain Cave, Chilliwack, British Columbia, Canada was examined. Sixty five bacterial isolates were successfully cultivated, purified, and identified based on 16S rRNA gene sequencing. Four distinguishable phyla, i.e., Actinobacteria (44.61%), Proteobacteria (27.69%), Firmicutes (20%) and Bacteroidetes (7.69%) were identified. Arthrobacter (21.53%) was identified as the major genus, followed by Sporosarcina (9.23%), Stenotrophomonas (9.23%), Streptomyces (6.15%), Brevundimonas (4.61%), and Crocebacterium (2.8%). Noteworthy, 12.3% of the population was recognized as unidentified bacteria. The isolates were evaluated for their potential antimicrobial activities against multidrug resistant microbial strains. Two species of the genus Streptomyces exhibited a wide range of antimicrobial activities against multidrug resistance (MDR) strains of Escherichia coli and Pseudomonas spp. along with non-resistant strains of Staphylococcus aureus and E. coli. However, all of the antimicrobial activities were only observed when the isolates were grown at 8 • C in different media. To the best of our knowledge, this is the first study conducted on the Iron Curtain Cave's bacterial diversity, and reveals some bacterial isolates that have never been reported from a cave. Bacterial isolates identified with antimicrobial properties demonstrated that the Iron Curtain Cave can be further considered as a potential habitat for antimicrobial agents.

Pseudogymnoascus destructans (Pd) is the causative agent of white-nose syndrome, which has resulted in the death of millions of bats in North America (NA) since 2006. Based on mortalities in eastern NA, the westward spread of infections likely poses a significant threat to western NA bats. To help prevent/reduce Pd infections in bats in western NA, we isolated bacteria from the wings of wild bats and screened for inhibitory activity against Pd. In total, we obtained 1,362 bacterial isolates from 265 wild bats of 13 species in western Canada. Among the 1,362 isolates, 96 showed inhibitory activity against Pd based on a coculture assay. The inhibitory activities varied widely among these isolates, ranging from slowing fungal growth to complete inhibition. Interestingly, host bats containing isolates with anti-Pd activities were widely distributed, with no apparent geographic or species-specific pattern. However, characteristics of roosting sites and host demography showed significant associations with the isolation of anti-Pd bacteria. Specifically, anthropogenic roosts and swabs from young males had higher frequencies of anti-Pd bacteria than those from natural roosts and those from other sex and age-groups, respectively. These anti-Pd bacteria could be potentially used to help mitigate the impact of WNS. Field trials using these as well as additional microbes from future screenings are needed in order to determine their effectiveness for the prevention and treatment against WNS.

Bacteria and archaea thrive in terrestrial subsurface environments because of their unique physiology. Over time, these unique microorganisms may have adapted to possess specialized metabolic pathways that sustain their continued existence in caves, one of harshest environments on earth. The present study elucidates cultivation based microbial diversity of the cave sediments and wall scrapings collected from seven different locations in Raspberry Rising Cave located in the Columbia Mountain Range, British Columbia, Canada. A total of 103 cultivable bacteria from the cave were isolated on various agar media including R2A, Hickey-Tresner, and Difco TM Actinomycetes Isolation agar media. Taxonomical phylogenetic analysis of the 16S rRNA gene of the bacterial isolates identified three major phyla: Proteobacteria (Class: Gammaproteobacteria) (51.45%), Actinobacteria (43.68%) and Bacteroidetes (3.88%). Among them, the major genus was Pseudomonas (48.54%) followed by Rhodococcus (39.80%) and Flavobacterium (3.88%). The genus Janthinobacterium and Arthrobacter contributed about 2.91% each, of the total population. Noteworthy, 0.99% were recognized as endophytic Proteobacteria. Furthermore, these bacterial isolates were evaluated for their potential antimicrobial activities against the multidrug resistant bacterial strains. Two bacterial isolates (RRC23, RRC75) showed antimicrobial activities against multidrug resistant (MDR) Escherichia coli #15-318 while RRC48 exhibited against methicillin resistant (MRSA) Staphylococcus aureus. The isolates RRC36 and RRC38 were identified to show antimicrobial activities against non-pathogenic isolates of Staphylococcus aureus. To the best of our knowledge, this is the first scientific study conducted and provides the insight in occurrence and distribution of the cultivated bacterial diversity from the Raspberry Rising Cave. Moreover, the antimicrobial properties exhibited by some of the bacterial isolates suggested that this cave system could be a resource for potential antibiotics, drugs or novel biologics of clinical relevance. cave microbial diversity, multi-drug resistant organisms, cultivation-based, antimicrobial activities, Raspberry Rising Cave, marble cave