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Symbiotic microorganisms that reside on the host skin serve as the primary defense against pathogens in vertebrates. Specifically, the skin microbiome of bats may play a crucial role in providing resistance against Pseudogymnoascus destructans ( Pd ), the pathogen causing white-nose syndrome. However, the epidermis symbiotic microbiome and its specific role in resisting Pd in highly resistant bats in Asia are still not well understood. In this study, we collected and characterized skin microbiota samples of 19 Myotis pilosus in China and explored the differences between Pd -positive and negative individuals. We identified inhibitory effects of these bacteria through cultivation methods. Our results revealed that the Simpson diversity index of the skin microbiota for positive individuals was significantly lower than that of negative individuals, and the relative abundance of Pseudomonas was significantly higher in positive bats. Regardless of whether individuals were positive or negative for Pd , the relative abundance of potentially antifungal genera in skin microbiota was high. Moreover, we successfully isolated 165 microbes from bat skin and 41 isolates from positive individuals able to inhibit Pd growth compared to only 12 isolates from negative individuals. A total of 10 genera of Pd -inhibiting bacteria were screened, among which the genera Algoriella , Glutamicibacter , and Psychrobacter were newly discovered as Pd -inhibiting genera. These Pd -inhibiting bacteria metabolized a variety of volatile compounds, including dimethyl trisulfide, dimethyl disulfide, propylene sulfide, 2-undecanone, and 2-nonanone, which were able to completely inhibit Pd growth at low concentrations.IMPORTANCERecently, white-nose syndrome has caused the deaths of millions of hibernating bats, even threatening some with regional extinction. Bats in China with high resistance to Pseudogymnoascus destructans can provide a powerful reference for studying the management of white-nose syndrome and understanding the bats against the pathogen's intrinsic mechanisms. This study sheds light on the crucial role of host symbiotic skin microorganisms in resistance to pathogenic fungi and highlights the potential for harnessing natural defense mechanisms for the prevention and treatment of white-nose syndrome. In addition, this may also provide promising candidates for the development of bioinsecticides and fungicides that offer new avenues for addressing fungal diseases in wildlife and agricultural environments., Competing Interests: The authors declare no conflict of interest.

Histoplasmosis is a mycotic infection principally affecting pulmonary tissue; sometimes, histoplasmosis can progress into a systemic disease. This infection involves immunocompetent and immunosuppressed human and other mammalian hosts, depending on particular circumstances. Histoplasmosis infection has been documented worldwide. The infection is acquired by inhaling infective mycelial propagules of the dimorphic fungus Histoplasma capsulatum. New reports of clinical cases of histoplasmosis in extreme latitudes could be related to human social adaptations and climate changes in the world, which are creating new favorable environments for this fungus and for bats, its major natural reservoirs and dispersers. Histoplasma has been isolated from most continents, and it is considered a complex of cryptic species, consisting of various groups of isolates that differ genetically and correlate with a particular geographic distribution. Based on updated studies, Histoplasma taxonomy is adjusting to new genetic data. Here, we have suggested that Histoplasma has at least 14 phylogenetic species distributed worldwide and new genotypes that could be under deliberation. Histoplasma 's geographic radiation began in South America millions of years ago when the continents were joined and the climate was favorable. For fungal spreading, the role of bats and some birds is crucial, although other natural factors could also participate.

White-nose syndrome (WNS) is an ongoing epizootic affecting multiple species of North American bats, caused by epidermal infections of the psychrophilic filamentous fungus Pseudogymnoascus destructans Since its introduction from Europe, WNS has spread rapidly across eastern North America and resulted in high mortality rates in bats. At present, the mechanisms behind its spread and the extent of its adaptation to different geographic and ecological niches remain unknown. The objective of this study was to examine the geographic patterns of phenotypic variation and the potential evidence for adaptation among strains representing broad geographic locations in eastern North America. The morphological features of these strains were evaluated on artificial medium, and the viability of asexual arthroconidia of representative strains was investigated after storage at high (23°C), moderate (14°C), and low (4°C) temperatures at different lengths of time. Our analyses identified evidence for a geographic pattern of colony morphology changes among the clonal descendants of the fungus, with trait values correlated with increased distance from the epicenter of WNS. Our genomic comparisons of three representative isolates revealed novel genetic polymorphisms and suggested potential candidate mutations that might be related to some of the phenotypic changes. These results show that even though this pathogen arrived in North America only recently and reproduces asexually, there has been substantial evolution and phenotypic diversification during its rapid clonal expansion. IMPORTANCE The causal agent of white-nose syndrome in bats is Pseudogymnoascus destructans , a filamentous fungus recently introduced from its native range in Europe. Infections caused by P. destructans have progressed across the eastern parts of Canada and the United States over the last 10 years. It is not clear how the disease is spread, as the pathogen is unable to grow above 23°C and ambient temperature can act as a barrier when hosts disperse. Here, we explore the patterns of phenotypic diversity and the germination of the fungal asexual spores, arthroconidia, from strains across a sizeable area of the epizootic range. Our analyses revealed evidence of adaptation along geographic gradients during its expansion. The results have implications for understanding the diversification of P. destructans and the limits of WNS spread in North America. Given the rapidly expanding distribution of WNS, a detailed understanding of the genetic bases for phenotypic variations in growth, reproduction, and dispersal of P. destructans is urgently needed to help control this disease., (Copyright © 2018 American Society for Microbiology.)

At least two-thirds of commercial antibiotics today are derived from Actinobacteria , more specifically from the genus Streptomyces Antibiotic resistance and new emerging diseases pose great challenges in the field of microbiology. Cave systems, in which actinobacteria are ubiquitous and abundant, represent new opportunities for the discovery of novel bacterial species and the study of their interactions with emergent pathogens. White-nose syndrome is an invasive bat disease caused by the fungus Pseudogymnoascus destructans , which has killed more than six million bats in the last 7 years. In this study, we isolated naturally occurring actinobacteria from white-nose syndrome (WNS)-free bats from five cave systems and surface locations in the vicinity in New Mexico and Arizona, USA. We sequenced the 16S rRNA region and tested 632 isolates from 12 different bat species using a bilayer plate method to evaluate antifungal activity. Thirty-six actinobacteria inhibited or stopped the growth of P. destructans , with 32 (88.9%) actinobacteria belonging to the genus Streptomyces Isolates in the genera Rhodococcus , Streptosporangium , Luteipulveratus , and Nocardiopsis also showed inhibition. Twenty-five of the isolates with antifungal activity against P. destructans represent 15 novel Streptomyces spp. based on multilocus sequence analysis. Our results suggest that bats in western North America caves possess novel bacterial microbiota with the potential to inhibit P. destructans IMPORTANCE This study reports the largest collection of actinobacteria from bats with activity against Pseudogymnoascus destructans , the fungal causative agent of white-nose syndrome. Using multigene analysis, we discovered 15 potential novel species. This research demonstrates that bats and caves may serve as a rich reservoir for novel Streptomyces species with antimicrobial bioactive compounds., (Copyright © 2017 American Society for Microbiology.)

Chlamydia-like organisms (CLOs) are recently identified members of the Chlamydiales order. CLOs share intracellular lifestyles and biphasic developmental cycles, and they have been detected in environmental samples as well as in various hosts such as amoebae and arthropods. In this study, we screened bat feces for the presence of CLOs by molecular analysis. Using pan-Chlamydiales PCR targeting the 16S rRNA gene, Chlamydiales DNA was detected in 54% of the specimens. PCR amplification, sequencing, and phylogenetic analysis of the 16S rRNA and 23S rRNA genes were used to classify positive specimens and infer their phylogenetic relationships. Most sequences matched best with Rhabdochlamydia species or uncultured Chlamydia sequences identified in ticks. Another set of sequences matched best with sequences of the Chlamydia genus or uncultured Chlamydiales from snakes. To gain evidence of whether CLOs in bat feces are merely diet borne, we analyzed insects trapped from the same location where the bats foraged. Interestingly, the CLO sequences resembling Rhabdochlamydia spp. were detected in insect material as well, but the other set of CLO sequences was not, suggesting that this set might not originate from prey. Thus, bats represent another potential host for Chlamydiales and could harbor novel, previously unidentified members of this order., Importance: Several pathogenic viruses are known to colonize bats, and recent analyses indicate that bats are also reservoir hosts for bacterial genera. Chlamydia-like organisms (CLOs) have been detected in several animal species. CLOs have high 16S rRNA sequence similarity to Chlamydiaceae and exhibit similar intracellular lifestyles and biphasic developmental cycles. Our study describes the frequent occurrence of CLO DNA in bat feces, suggesting an expanding host species spectrum for the Chlamydiales As bats can acquire various infectious agents through their diet, prey insects were also studied. We identified CLO sequences in bats that matched best with sequences in prey insects but also CLO sequences not detected in prey insects. This suggests that a portion of CLO DNA present in bat feces is not prey borne. Furthermore, some sequences from bat droppings not originating from their diet might well represent novel, previously unidentified members of the Chlamydiales order., (Copyright © 2016 American Society for Microbiology.)

Since 2006, Geomyces destructans, the causative agent of white nose syndrome (WNS), has killed over 5.7 million bats in North America. The current hypothesis suggests that this novel fungus is an invasive species from Europe, but little is known about the diversity within the genus Geomyces and its distribution on bats in the United States. We documented the psychrophilic and psychrotolerant fungal flora of hibernating bats prior to the arrival of WNS using culture-based techniques. A total of 149 cultures, which were obtained from 30 bats in five bat hibernacula located in four caves and one mine, were sequenced for the entire internal transcribed spacer (ITS) nuclear ribosomal DNA (nrDNA) region. Approximately 53 operational taxonomic units (OTUs) at 97% similarity were recovered from bat wings, with the community dominated by fungi within the genera Cladosporium, Fusarium, Geomyces, Mortierella, Penicillium, and Trichosporon. Eleven Geomyces isolates were obtained and placed in at least seven distinct Geomyces clades based on maximum-likelihood phylogenetic analyses. Temperature experiments revealed that all Geomyces strains isolated are psychrotolerant, unlike G. destructans, which is a true psychrophile. Our results confirm that a large diversity of fungi, including several Geomyces isolates, occurs on bats prior to the arrival of WNS. Most of these isolates were obtained from damaged wings. Additional studies need to be conducted to determine potential ecological roles of these abundant Geomyces strains isolated from bats.

White-nose syndrome (WNS) is an emerging disease of hibernating bats caused by the recently described fungus Geomyces destructans. First isolated in 2008, the origins of this fungus in North America and its ability to persist in the environment remain undefined. To investigate the correlation between manifestation of WNS and distribution of G. destructans in the United States, we analyzed sediment samples collected from 55 bat hibernacula (caves and mines) both within and outside the known range of WNS using a newly developed real-time PCR assay. Geomyces destructans was detected in 17 of 21 sites within the known range of WNS at the time when the samples were collected; the fungus was not found in 28 sites beyond the known range of the disease at the time when environmental samples were collected. These data indicate that the distribution of G. destructans is correlated with disease in hibernating bats and support the hypothesis that the fungus is likely an exotic species in North America. Additionally, we examined whether G. destructans persists in infested bat hibernacula when bats are absent. Sediment samples were collected from 14 WNS-positive hibernacula, and the samples were screened for viable fungus by using a culture technique. Viable G. destructans was cultivated from 7 of the 14 sites sampled during late summer, when bats were no longer in hibernation, suggesting that the fungus can persist in the environment in the absence of bat hosts for long periods of time.

Yeasts from caves have rarely been examined. We examined yeasts collected from bat guano samples from 20 bat-inhabited limestone and volcanic caves located in 11 prefectures in Japan. Of approximately 700 yeast-like colonies, nine Trichosporon species were recovered from 15 caves. Two of these were known species, and the remaining seven are potentially novel species, based on molecular phylogenetic analyses. In addition to Trichosporon species, identifiable strains of eight ascomycetous yeasts and one basidiomycetous yeast were recovered at frequencies of 5 to 35%. Our findings suggest that Trichosporon spp. are the major yeast species in bat guano in Japan and that bat guano is a potentially rich source of previously undescribed yeast species.

A total of 2,886 bats captured in the Amazon Basin of Brazil were processed for the isolation of fungi. From the livers, spleens, and lungs of 155 bats (5.4%), 186 fungal isolates of the genera Candida (123 isolates), Trichosporon (26 isolates), Torulopsis (25 isolates), Kluyveromyces (11 isolates), and Geotrichum (1 isolate) were recovered. Seven known pathogenic species were present: Candida parapsilosis, C. guilliermondii, C. albicans, C. stellatoidea, C. pseudotropicalis, Trichosporon beigelii, and Torulopsis glabrata. Twenty-three culture-positive bats showed identical fungal colonization in multiple organs or mixed colonization in a single organ. The fungal isolation rates for individual bat species varied from 1 fungus per 87 bats to 3 fungi per 13 bats, and the mycoflora diversity for members of an individual fungus-bearing bat species varied from 16 fungi per 40 bats to 7 fungi per 6 bats. Of the 38 fungal species isolated, 36 had not been previously described as in vivo bat isolates. Of the 27 culture-positive bat species, 21 had not been previously described as mammalian hosts for medically or nonmedically important fungi.