Yersinia species isolated from bats, Germany

Bat-associated microbes: Opportunities and perils, an overview

The potential biotechnological uses of bat-associated bacteria are discussed briefly, indicating avenues for biotechnological applications of bat-associated microbes. The uniqueness of bats in terms of their lifestyle, genomes and molecular immunology may predispose bats to act as disease reservoirs. Molecular phylogenetic analysis has shown several instances of bats harbouring the ancestral lineages of bacterial (Bartonella), protozoal (Plasmodium, Trypanosoma cruzi) and viral (SARS-CoV2) pathogens infecting humans. Along with the transmission of viruses from bats, we also discuss the potential roles of bat-associated bacteria, fungi, and protozoan parasites in emerging diseases. Current evidence suggests that environmental changes and interactions between wildlife, livestock, and humans contribute to the spill-over of infectious agents from bats to other hosts. Domestic animals including livestock may act as intermediate amplifying hosts for bat-origin pathogens to transmit to humans. An increasing number of studies investigating bat pathogen diversity and infection dynamics have been published. However, whether or how these infectious agents are transmitted both within bat populations and to other hosts, including humans, often remains unknown. Metagenomic approaches are uncovering the dynamics and distribution of potential pathogens in bat microbiomes, which might improve the understanding of disease emergence and transmission. Here, we summarize the current knowledge on bat zoonoses of public health concern and flag the gaps in the knowledge to enable further research and allocation of resources for tackling future outbreaks.

Trends in Bacterial Pathogens of Bats: Global Distribution and Knowledge Gaps

Bats have received considerable recent attention for infectious disease research because of their potential to host and transmit viruses, including Ebola, Hendra, Nipah, and multiple coronaviruses. These pathogens are occasionally transmitted from bats to wildlife, livestock, and to humans, directly or through other bridging (intermediate) hosts. Due to their public health relevance, zoonotic viruses are a primary focus of research attention. In contrast, other emerging pathogens of bats, such as bacteria, are vastly understudied despite their ubiquity and diversity. Here, we describe the currently known host ranges and geographic distributional patterns of potentially zoonotic bacterial genera in bats, using published presence-absence data of pathogen occurrence. We identify apparent gaps in our understanding of the distribution of these pathogens on a global scale. The most frequently detected bacterial genera in bats are Bartonella, Leptospira, and Mycoplasma. However, a wide variety of other potentially zoonotic bacterial genera are also occasionally found in bats, such as Anaplasma, Brucella, Borrelia, Coxiella, Ehrlichia, Francisella, Neorickettsia, and Rickettsia. The bat families Phyllostomidae, Vespertilionidae, and Pteropodidae are most frequently reported as hosts of bacterial pathogens; however, the presence of at least one bacterial genus was confirmed in all 15 bat families tested. On a spatial scale, molecular diagnostics of samples from 58 countries and four overseas departments and island states (French Guiana, Mayotte, New Caledonia, and Réunion Island) reported testing for at least one bacterial pathogen in bats. We also identified geographical areas that have been mostly neglected during bacterial pathogen research in bats, such as the Afrotropical region and Southern Asia. Current knowledge on the distribution of potentially zoonotic bacterial genera in bats is strongly biased by research effort towards certain taxonomic groups and geographic regions. Identifying these biases can guide future surveillance efforts, contributing to a better understanding of the ecoepidemiology of zoonotic pathogens in bats.

An overview of bats microbiota and its implication in transmissible diseases

Recent pandemic events have raised the attention of the public on the interactions between human and environment, with particular regard to the more and more feasible transmission to humans of micro-organisms hosted by wild-type species, due to the increasing interspecies contacts originating from human’s activities. Bats, due to their being flying mammals and their increasing promiscuity with humans, have been recognized as hosts frequently capable of transmitting disease-causing microorganisms. Therefore, it is of considerable interest and importance to have a picture as clear as possible of the microorganisms that are hosted by bats. Here we focus on our current knowledge on bats microbiota. We review the most recent literature on this subject, also in view of the bat’s body compartments, their dietary preferences and their habitat. Several pathogenic bacteria, including many carrying multidrug resistance, are indeed common guests of these small mammals, underlining the importance of preserving their habitat, not only to protect them from anthropogenic activities, but also to minimize the spreading of infectious diseases.

Differences in acute phase response to bacterial, fungal and viral antigens in greater mouse-eared bats (Myotis myotis)

The acute phase response (APR) is an evolutionarily well-conserved part of the innate immune defense against pathogens. However, recent studies in bats yielded surprisingly diverse results compared to previous APR studies on both vertebrate and invertebrate species. This is especially interesting due to the known role of bats as reservoirs for viruses and other intracellular pathogens, while being susceptible to extracellular microorganisms such as some bacteria and fungi. To better understand these discrepancies and the reservoir-competence of bats, we mimicked bacterial, viral and fungal infections in greater mouse-eared bats (Myotis myotis) and quantified different aspects of the APR over a two-day period. Individuals reacted most strongly to a viral (PolyI:C) and a bacterial (LPS) antigen, reflected by an increase of haptoglobin levels (LPS) and an increase of the neutrophil-to-lymphocyte-ratio (PolyI:C and LPS). We did not detect fever, leukocytosis, body mass loss, or a change in the overall functioning of the innate immunity upon challenge with any antigen. We add evidence that bats respond selectively with APR to specific pathogens and that the activation of different parts of the immune system is species-specific.

First report on metabarcoding analysis of gut microbiome in Island Flying Fox (Pteropushypomelanus) in island populations of Malaysia

Flying fox (Pteropushypomelanus) belongs to the frugivorous bats, which play a crucial role in maintaining proper functioning of an ecosystem and conservation of the environment. Bats are well-known carriers of pathogenic viruses, such as BatCov RaTG13 from the coronavirus family that share 90.55% with SARS-CoV-2, the pathogen causing recent global pandemic coronavirus disease 19 (COVID-19). However, bats' possible role as a carrier of pathogenic bacteria is less explored. Here, using metabarcoding analysis through high-throughput sequencing, we explored the gut microbiome composition of different island populations on the east and west coasts of Peninsula Malaysia. The 16S rRNA gene in samples from Redang Island, Langkawi Island, Pangkor Island and Tinggi Island was amplified. Bacterial community composition and structure were analysed with α and β diversity metrics. A total of 25,658 operational taxonomic units at 97% similarity were assigned to eight phyla, 44 families, 61 genera and 94 species of microbes. The Proteobacteria was the dominant phylum in all populations. Meanwhile, the genera Enterobacter, Pseudomonas and Klebsiella, isolated in this study, were previously found in the rectum of other fruit bats. Our analyses suggest that Redang Island and Langkawi Island have high bacteria diversity. Thus, we found geographic locality is a strong predictor of microbial community composition and observed a positive correlation between ecological features and bacterial richness.

Genetic identification of bat species for pathogen surveillance across France

With more than 1400 chiropteran species identified to date, bats comprise one-fifth of all mammalian species worldwide. Many studies have associated viral zoonoses with 45 different species of bats in the EU, which cluster within 5 families of bats. For example, the Serotine bats are infected by European Bat 1 Lyssavirus throughout Europe while Myotis bats are shown infected by coronavirus, herpesvirus and paramyxovirus. Correct host species identification is important to increase our knowledge of the ecology and evolutionary pattern of bat viruses in the EU. Bat species identification is commonly determined using morphological keys. Morphological determination of bat species from bat carcasses can be limited in some cases, due to the state of decomposition or nearly indistinguishable morphological features in juvenile bats and can lead to misidentifications. The overall objective of our study was to identify insectivorous bat species using molecular biology tools with the amplification of the partial cytochrome b gene of mitochondrial DNA. Two types of samples were tested in this study, bat wing punches and bat faeces. A total of 163 bat wing punches representing 22 species, and 31 faecal pellets representing 7 species were included in the study. From the 163 bat wing punches tested, a total of 159 were genetically identified from amplification of the partial cyt b gene. All 31 faecal pellets were genetically identified based on the cyt b gene. A comparison between morphological and genetic determination showed 21 misidentifications from the 163 wing punches, representing ~12.5% of misidentifications of morphological determination compared with the genetic method, across 11 species. In addition, genetic determination allowed the identification of 24 out of 25 morphologically non-determined bat samples. Our findings demonstrate the importance of a genetic approach as an efficient and reliable method to identify bat species precisely.

Evidence of Extensive Circulation of Yersinia enterocolitica in Rodents and Shrews in Natural Habitats from Retrospective and Perspective Studies in South Caucasus

Yersinia enterocolitica culture-positive rodents and shrews were reported in different territories across Georgia during 14 of 17 years of investigations conducted for the period of 1981–1997. In total, Y. enterocolitica was isolated from 2052 rodents (15 species) and 33 shrews. Most isolates were obtained from Microtus arvalis, Rattus norvegicus, Mus musculus, and Apodemus spp. During the prospective study (2017−2019), isolates of Yersinia-like bacteria were cultured from 53 rodents collected in four parts of Georgia. All the Yersinia-like isolates were confirmed as Y. enterocolitica based on the API 20E and the BD Phenix50 tests. Whole-genome (WG) sequencing of five rodents and one shrew strain of Y. enterocolitica revealed that they possessed a set of virulence genes characteristic of the potentially pathogenic strains of biogroup 1A. All isolates lacked distinguished virulence determinants for YstA, Ail, TccC, VirF, and virulence plasmid pYV but carried the genes for YstB, YmoA, HemPR-HmuVSTU, YaxAB, PhlA, PldA, ArsCBR, and a flagellar apparatus. One strain contained a gene highly homologous to heat-labile enterotoxin, a chain of E. coli, a function not previously described for Y. enterocolitica. The WG single-nucleotide polymorphism-based typing placed the isolates in four distinct phylogenetic clusters.

The virome of German bats: comparing virus discovery approaches

Bats are known to be reservoirs of several highly pathogenic viruses. Hence, the interest in bat virus discovery has been increasing rapidly over the last decade. So far, most studies have focused on a single type of virus detection method, either PCR, virus isolation or virome sequencing. Here we present a comprehensive approach in virus discovery, using all three discovery methods on samples from the same bats. By family-specific PCR screening we found sequences of paramyxoviruses, adenoviruses, herpesviruses and one coronavirus. By cell culture we isolated a novel bat adenovirus and bat orthoreovirus. Virome sequencing revealed viral sequences of ten different virus families and orders: three bat nairoviruses, three phenuiviruses, one orbivirus, one rotavirus, one orthoreovirus, one mononegavirus, five parvoviruses, seven picornaviruses, three retroviruses, one totivirus and two thymoviruses were discovered. Of all viruses identified by family-specific PCR in the original samples, none was found by metagenomic sequencing. Vice versa, none of the viruses found by the metagenomic virome approach was detected by family-specific PCRs targeting the same family. The discrepancy of detected viruses by different detection approaches suggests that a combined approach using different detection methods is necessary for virus discovery studies.

Yersinia pseudotuberculosis serotype O:1 infection in a captive Seba's short tailed-fruit bat (Carollia perspicillata) colony in Switzerland

Background

Between February and April 2016, a slight increase in mortality was observed in a colony consisting of 400 captive Seba’s short-tailed bats (Carollia perspicillata). These animals cohabited with other nocturnal animal species in a dome of a private zoo in Switzerland.

Results

Gross and histological analysis of two (14.3%) out of the 13 animals submitted for necropsy within this period revealed a necrosuppurative pneumonia, hepatitis, splenitis, enterocolitis, and endometritis, with abundant intralesional colonies of Gram-negative rods. Yersinia (Y.) pseudotuberculosis serotype O:1 and biotype 1 belonging to the sequence type ST90 was isolated from the affected organs in both animals. Following this diagnosis, ¼ of the colony (99 animals) was culled and submitted for gross and histopathological analysis, and a bacterial culture selective for Yersinia spp. of lung, liver, and spleen was performed. From these 99 animals, one gravid female was tested and found to be positive for Y. pseudotuberculosis in the absence of clinical symptoms and histopathological lesions. PCR analysis of altogether three bacterial isolates for virulence factors revealed the presence of the ail gene, and one isolate was also positive for the virF and yadA plasmid genes.

Conclusions

These findings suggest that Carollia perspicillata are susceptible to lethal yersiniosis but do not represent a regular reservoir for Y. pseudotuberculosis. Culling of ¼ of the population was sufficient to limit the spread of this infection among the colony. Moreover, no infections were detected in cohabitant nocturnal animals and caretakers, indicating that the zoonotic risk in this case was low.

First detection of bat-borne Issyk-Kul virus in Europe

Bats have been gaining attention as potential reservoir hosts of numerous viruses pathogenic to animals and man. Issyk-Kul virus, a member of the family Nairoviridae, was first isolated in the 1970s from vespertilionid bats in Central Asia. Issyk-Kul virus has been described as human-pathogenic virus, causing febrile outbreaks in humans with headaches, myalgia and nausea. Here we describe the detection of a novel strain of Issyk-Kul virus from Eptesicus nilssonii in Germany. This finding indicates for the first time the prevalence of these zoonotic viruses in Europe.

A Culture-Based ID of Micromycetes on the Wing Membranes of Greater Mouse-Eared Bats (Myotis myotis) from the "Nietoperek" Site (Poland)

Bats play important functions in ecosystems and many of them are threatened with extinction. Thus, the monitoring of the health status and prevention of diseases seem to be important aspects of welfare and conservation of these mammals. The main goal of the study was the identification of culturable fungal species colonizing the wing membranes of female greater mouse-eared bat (Myotis myotis) during spring emergence from the "Nietoperek" underground hibernation site by the use of genetic and phenotypic analyses. The study site is situated in Western Poland (52°25' N, 15°32' E) and is ranked within the top 10 largest hibernation sites in the European Union. The number of hibernating bats in the winter exceeds 39,000 individuals of 12 species, with M. myotis being the most common one. The wing membranes of M. myotis were sampled using sterile swabs wetted in physiological saline (0.85% NaCl). Potato dextrose agar (PDA) plates were incubated in the dark at 8, 24 and 36 ± 1 °C for 3 up to 42 days. All fungi isolated from the surface of wing membranes were assigned to 17 distinct fungal isolates belonging to 17 fungal species. Penicillium chrysogenum was the most frequently isolated species. Some of these fungal species might have a pathogenic potential for bats and other mammals. However, taking into account habitat preferences and the life cycle of bats, it can be assumed that some fungi were accidentally obtained from the surface of vegetation during early spring activity. Moreover, Pseudogymnoascus destructans (Pd)-the causative agent of the White Nose Syndrome (WNS)-was not found during testing, despite it was found very often in M. myotis during previous studies in this same location.

Identification of a Novel Yersinia enterocolitica Strain from Bats in Association with a Bat Die-Off That Occurred in Georgia (Caucasus)

Yersinia entercolitica is a bacterial species within the genus Yersinia, mostly known as a human enteric pathogen, but also recognized as a zoonotic agent widespread in domestic pigs. Findings of this bacterium in wild animals are very limited. The current report presents results of the identification of cultures of Y. entercolitica from dead bats after a massive bat die-off in a cave in western Georgia. The growth of bacterial colonies morphologically suspected as Yersinia was observed from three intestine tissues of 11 bats belonging to the Miniopterus schreibersii species. These three isolates were identified as Y. enterocolitica based on the API29 assay. No growth of Brucella or Francisella bacteria was observed from tissues of dead bats. Full genomes (a size between 4.6–4.7 Mbp) of the Yersinia strains isolated from bats were analyzed. The phylogenetic sequence analyses of the genomes demonstrated that all strains were nearly identical and formed a distinct cluster with the closest similarity to the environmental isolate O:36/1A. The bat isolates represent low-pathogenicity Biotype 1A strains lacking the genes for the Ail, Yst-a, Ysa, and virulence plasmid pYV, while containing the genes for Inv, YstB, and MyfA. Further characterization of the novel strains cultured from bats can provide a clue for the determination of the pathogenic properties of those strains.

The Faecal Microbiome of Building-Dwelling Insectivorous Bats (Myotis myotis and Rhinolophus hipposideros) also Contains Antibiotic-Resistant Bacterial Representatives

The bacteriome of bat faeces and bat guano is still not well known, despite the increasing knowledge of it as a potential source of pathogenic and/or antibiotic-resistant species. In this study, the faecal microbiome composition of two building-dwelling insectivorous bat species (Myotis myotis and Rhinolophus hipposideros) was analysed using cultivation-based and non-cultivation-based approaches. The cultivation analyses indicate the dominance of Gram-positive bacteria, represented by the genera Enterococcus, Lactococcus and Lactobacillus. Non-cultivation analysis based on 16S rRNA DGGE assays provided a different pattern, with the genus Rahnella found to predominate in the faecal microbiome. The analyses showed bat species to be the most important factor influencing the structure of the guano-associated microbial population. The presence of several possible human pathogens (Hafnia alvei, Serratia fonticola, S. liquefaciens) and antibiotic-resistant bacteria (e.g. vancomycin resistant Staphylococcus nepalensis) was detected in faeces samples, indicating possible human health risks associated with bat guano. Although the bat-human transmission of infection caused by pathogenic bacteria has not been reliably confirmed to date, this possibility should not be underestimated. Given the very important ecosystem services of bats, particular those studied herein, it is time to think about appropriate management of bat populations inhabiting man-made buildings and potential conflicts with humans.

Special Features of Bat Microbiota Differ From Those of Terrestrial Mammals

Bats (order Chiroptera) are one of the most diverse and widely distributed group of mammals with a close relationship to humans. Over the past few decades, a number of studies have been performed on bat viruses; in contrast, bacterial pathogens carried by bats were largely neglected. As more bacterial pathogens are being identified from bats, the need to study their natural microbiota is becoming urgent. In the current study, fecal samples of four bat species from different locations of China were analyzed for their microbiota composition. Together with the results of others, we concluded that bat microbiota is most commonly dominated by Firmicutes and Proteobacteria; the strict anaerobic phylum Bacteroidetes, which is dominant in other terrestrial mammals, especially humans and mice, is relatively rare in bats. This phenomenon was interpreted as a result of a highly specified gastrointestinal tract in adaptation to the flying lifestyle of bats. Further comparative study implied that bat microbiota resemble those of the order Carnivora. To discover potential bacterial pathogens, a database was generated containing the 16S rRNA gene sequences of known bacterial pathogens. Potential bacterial pathogens belonging to 12 genera were detected such as Salmonella, Shigella, and Yersinia, among which some have been previously reported in bats. This study demonstrated high resolution and repeatability in detecting organisms of rare existence, and the results could be used as guidance for future bacterial pathogen isolation.

Culture-dependent and metagenomic analysis of lesser horseshoe bats' gut microbiome revealing unique bacterial diversity and signatures of potential human pathogens

Bats are highly diverse and ecologically important mammals. They harbor various bacteria, viruses, and fungal communities that are either beneficial or potentially pathogenic. Extensive metagenomic studies in bats are limited, particularly for the gut, and to date, there are no reports on the bacterial diversity of Rhinolophus monoceros from Meghalaya, India. There are limited studies on the isolation of potential harmful or beneficial bacteria and their interactions with the environment through culture-dependent approaches. Therefore, high-throughput screening was used to understand the population structure, genetic diversity, and ecological role of the microorganisms. High-throughput sequencing of the 16S rRNA marker for gene mapping showed that the gut samples constitute a diverse group of bacteria that is dominated by Proteobacteria, followed by Firmicutes. The bacterial genera Corynebacterium and Mycobacterium were also observed in the Illumina dataset. Illumina sequencing revealed eight bacterial phyla composed of 112 genera. The metagenomic analysis of the OTUs from the gut revealed diverse bacterial communities as well as zoonotic and human pathogens. There were differences in the bacterial communities between the two methods used in this study, which could be related to host specificity, diet, and habitat. The culture-dependent technique resulted in the isolation of 35 bacterial isolates, of which Bacillus cereus and B. anthracis are well-known bacterial pathogens that show virulent traits including hemolytic and proteolytic activities. Pseudomonas stutzeri is an opportunistic human pathogen that was also isolated and showed similar traits. Antibiotic sensitivity tests were performed on all 35 isolates, and different antibiotics were used for Gram-positive and -negative bacteria. The result showed that some isolates are resistant to antibiotics such as penicillin G and Cefoxitin. This report on gut bacterial communities could attract interest in the possibility of isolating and characterizing bacteria for the production of antibiotics, enzymes, plant growth promoters, and probiotics. However, the presence of potential pathogenic bacteria that may impose health hazards cannot be ignored and needs to be studied further.

Clostridioides difficile in bat guano

Bats are associated with the emergence of several mammalian diseases. Their sessional migration, and tendency to form large colonies in close proximity to human habitats enables effective intra- and inter-species transmission of pathogens. Clostridioides difficile is an important enteric pathogen in humans and animals; however, the source of its dissemination in the population is unknown. The purpose of this study was to determine the prevalence of C. difficile in bats, and to characterize C. difficile isolates. Feces (n = 93) was sampled from bats during their migration across Europe. Eighteen samples (19.4%) were positive for C. difficile; ribotypes 078, 056, and a new ribotype CDB3 were identified. Clostridioides difficile ribotypes 078 and 056 are associated with human and animal diseases. The C. difficile prevalence and ribotypes in this study do not necessarily identify bats as a significant source, but more likely as an indicator of C. difficile perpetuation in the environment.

Bacteria richness and antibiotic-resistance in bats from a protected area in the Atlantic Forest of Southeastern Brazil

Bats play key ecological roles, also hosting many zoonotic pathogens. Neotropical bat microbiota is still poorly known. We speculate that their dietary habits strongly influence their microbiota richness and antibiotic-resistance patterns, which represent growing and serious public health and environmental issue. Here we describe the aerobic microbiota richness of bats from an Atlantic Forest remnant in Southeastern Brazil, and the antibiotic-resistance patterns of bacteria of clinical importance. Oral and rectal cavities of 113 bats from Carlos Botelho State Park were swabbed. Samples were plated on 5% sheep blood and MacConkey agar and identified by the MALDI-TOF technique. Antibiotic susceptibility tests were performed using Kirby-Bauer’s antibiotic disc diffusion technique.We identified 596 isolates at the genus level and tentatively to the species level. Proteobacteria was the most abundant phylum in all the dietary guilds, representing 87% of the total identified samples. The most common bacteria within bat individuals were Escherichia coli, Klebsiella oxytoca and Serratia marcescens, and within bat species were Serratia marcescens, Pseudomonas sp. and Staphylococcus sp. Frugivores presented the most diverse microbiota. In general, the antibiogram results indicated a low occurrence of resistance on eigth potentially pathogenic bacteria species. The resistance to antibiotics found on our samples was related mostly to the intrinsic resistance of the tested species.The low occurrence of resistant bacteria in our samples could be related to the well preserved environment where bats were caught. Once the major causes of resistance-acquiring are related to anthropic activites, the controlled access of tourists on certain regions of the Park seems to be effectively protecting the environment.

Survey of Parasitic Bacteria in Bat Bugs, Colorado

Bat bugs (Cimex adjunctus Barber) (Hemiptera: Cimicidae) collected from big brown bats (Eptesicus fuscus Palisot de Beauvoir) in Colorado, United States were assessed for the presence of Bartonella, Brucella, and Yersinia spp. using molecular techniques. No evidence of Brucella or Yersinia infection was found in the 55 specimens collected; however, 4/55 (7.3%) of the specimens were positive for Bartonella DNA. Multi-locus characterization of Bartonella DNA shows that sequences in bat bugs are phylogenetically related to other Bartonella isolates and sequences from European bats.

Chiroptera

With over 1200 species identified, bats represent almost one quarter of the world’s mammals. Bats provide crucial environmental services, such as insect control and pollination, and inhabit a wide variety of ecological niches on all continents except Antarctica. Despite their ubiquity and ecological importance, relatively little has been published on diseases of bats, while much has been written on bats’ role as reservoirs in disease transmission. This chapter will focus on diseases and pathologic processes most commonly reported in captive and free-ranging bats. Unique anatomical and histological features and common infectious and non-infectious diseases will be discussed. As recognition of both the importance and vulnerability of bats grows, particularly following population declines in North America due to the introduction of the fungal disease white-nose syndrome, efforts should be made to better understand threats to the health of this unique group of mammals.

Novel hemotropic mycoplasmas are widespread and genetically diverse in vampire bats

Bats (Order: Chiroptera) have been widely studied as reservoir hosts for viruses of concern for human and animal health. However, whether bats are equally competent hosts of non-viral pathogens such as bacteria remains an important open question. Here, we surveyed blood and saliva samples of vampire bats from Peru and Belize for hemotropic Mycoplasma spp. (hemoplasmas), bacteria that can cause inapparent infection or anemia in hosts. 16S rRNA gene amplification of blood showed 67% (150/223) of common vampire bats (Desmodus rotundus) were infected by hemoplasmas. Sequencing of the 16S rRNA gene amplicons revealed three novel genotypes that were phylogenetically related but not identical to hemoplasmas described from other (non-vampire) bat species, rodents, humans, and non-human primates. Hemoplasma prevalence in vampire bats was highest in non-reproductive and young individuals, did not differ by country, and was relatively stable over time (i.e., endemic). Metagenomics from pooled D. rotundus saliva from Peru detected non-hemotropic Mycoplasma species and hemoplasma genotypes phylogenetically similar to those identified in blood, providing indirect evidence for potential direct transmission of hemoplasmas through biting or social contacts. This study demonstrates vampire bats host several novel hemoplasmas and sheds light on risk factors for infection and basic transmission routes. Given the high frequency of direct contacts that arise when vampire bats feed on humans, domestic animals, and wildlife, the potential of these bacteria to be transmitted between species should be investigated in future work.

Highly diverse and antimicrobial susceptible Escherichia coli display a naïve bacterial population in fruit bats from the Republic of Congo

Bats are suspected to be a reservoir of several bacterial and viral pathogens relevant to animal and human health, but studies on Escherichia coli in these animals are sparse. We investigated the presence of E. coli in tissue samples (liver, lung and intestines) collected from 50 fruit bats of five different species (Eidolon helvum, Epomops franqueti, Hypsignathus monstrosus, Myonycteris torquata, Rousettus aegyptiacus) of two different areas in the Republic of Congo between 2009 and 2010. To assess E. coli pathotypes and phylogenetic relationships, we determined the presence of 59 virulence associated genes and multilocus sequence types (STs). Isolates were further tested for their susceptibility to several antimicrobial substances by agar disk diffusion test and for the presence of an Extended-Spectrum Beta-Lactamase phenotype. E. coli was detected in 60% of the bats analysed. The diversity of E. coli strains was very high, with 37 different STs within 40 isolates. Occasionally, we detected sequence types (e.g. ST69, ST127, and ST131) and pathotypes (e.g. ExPEC, EPEC and atypical EPEC), which are known pathogens in human and/or animal infections. Although the majority of strains were assigned to phylogenetic group B2 (46.2%), which is linked with the ExPEC pathovar, occurrence of virulence-associated genes in these strains were unexpectedly low. Due to this, and as only few of the E. coli isolates showed intermediate resistance to certain antimicrobial substances, we assume a rather naïve E. coli population, lacking contact to humans or domestic animals. Future studies featuring in depth comparative whole genome sequence analyses will provide insights into the microevolution of this interesting strain collection.

Molecular Survey of Bacterial Zoonotic Agents in Bats from the Country of Georgia (Caucasus)

Bats are important reservoirs for many zoonotic pathogens. However, no surveys of bacterial pathogens in bats have been performed in the Caucasus region. To understand the occurrence and distribution of bacterial infections in these mammals, 218 bats belonging to eight species collected from four regions of Georgia were examined for Bartonella, Brucella, Leptospira, and Yersinia using molecular approaches. Bartonella DNA was detected in 77 (35%) bats from all eight species and was distributed in all four regions. The prevalence ranged 6–50% per bat species. The Bartonella DNA represented 25 unique genetic variants that clustered into 21 lineages. Brucella DNA was detected in two Miniopterus schreibersii bats and in two Myotis blythii bats, all of which were from Imereti (west-central region). Leptospira DNA was detected in 25 (13%) bats that included four M. schreibersii bats and 21 M. blythii bats collected from two regions. The Leptospira sequences represented five genetic variants with one of them being closely related to the zoonotic pathogen L. interrogans (98.6% genetic identity). No Yersinia DNA was detected in the bats. Mixed infections were observed in several cases. One M. blythii bat and one M. schreibersii bat were co-infected with Bartonella, Brucella, and Leptospira; one M. blythii bat and one M. schreibersii bat were co-infected with Bartonella and Brucella; 15 M. blythii bats and three M. schreibersii bats were co-infected with Bartonella and Leptospira. Our results suggest that bats in Georgia are exposed to multiple bacterial infections. Further studies are needed to evaluate pathogenicity of these agents to bats and their zoonotic potential.

Bacterial diversity indicates dietary overlap among bats of different feeding habits

Bats are among the most conspicuous mammals with extraordinary adaptations. They play a key role in the ecosystem. Frugivorous bats are important seed dispersing agents that help in maintaining forest tree diversity, while insectivorous bats are natural insect pest control agents. Several previous reports suggest that bats are reservoir of viruses; nonetheless their bacterial counterparts are relatively less explored. The present study describes the microbial diversity associated with the intestine of bats from different regions of India. Our observations stipulate that there is substantial sharing of bacterial communities between the insectivorous and frugivorous bats, which signifies fairly large dietary overlap. We also observed the presence of higher abundance of Mycoplasma in Cynopterus species of bats, indicating possible Mycoplasma infection. Considering the scarcity of literature related to microbial communities of bat intestinal tract, this study can direct future microbial diversity studies in bats with reference to their dietary habits, host-bacteria interaction and zoonosis.

Immunology of bats and their viruses: challenges and opportunities

Bats are reservoir hosts of several high-impact viruses that cause significant human diseases, including Nipah virus, Marburg virus and rabies virus. They also harbor many other viruses that are thought to have caused disease in humans after spillover into intermediate hosts, including SARS and MERS coronaviruses. As is usual with reservoir hosts, these viruses apparently cause little or no pathology in bats. Despite the importance of bats as reservoir hosts of zoonotic and potentially zoonotic agents, virtually nothing is known about the host/virus relationships; principally because few colonies of bats are available for experimental infections, a lack of reagents, methods and expertise for studying bat antiviral responses and immunology, and the difficulty of conducting meaningful field work. These challenges can be addressed, in part, with new technologies that are species-independent that can provide insight into the interactions of bats and viruses, which should clarify how the viruses persist in nature, and what risk factors might facilitate transmission to humans and livestock.

Isolation and identification of gastrointestinal microbiota from the short-nosed fruit bat Cynopterus brachyotis brachyotis

Studies on the microbial ecology of gut microbiota in bats are limited and such information is necessary in determining the ecological significance of these hosts. Short-nosed fruit bats (Cynopterus brachyotis brachyotis) are good candidates for microbiota studies given their close association with humans in urban areas. Thus, this study explores the gut microbiota of this species from Peninsular Malaysia by means of biochemical tests and 16S rRNA gene sequences analysis. The estimation of viable bacteria present in the stomach and intestine of C. b. brachyotis ranged from 3.06×10(10) to 1.36×10(15)CFU/ml for stomach fluid and 1.92×10(10) to 6.10×10(15)CFU/ml for intestinal fluid. A total of 34 isolates from the stomach and intestine of seven C. b. brachyotis were retrieved. A total of 16 species of bacteria from eight genera (Bacillus, Enterobacter, Enterococcus, Escherichia, Klebsiella, Pantoea, Pseudomonas and Serratia) were identified, Enterobacteriaceae being the most prevalent, contributing 12 out of 16 species isolated. Most isolates from the Family Enterobacteriaceae have been reported as pathogens to humans and wildlife. With the possibility of human wildlife transmission, the findings of this study focus on the importance of bats as reservoirs of potential bacterial pathogens.

Characterization of Staphylococcus aureus isolates from faecal samples of the Straw-Coloured Fruit Bat (Eidolon helvum) in Obafemi Awolowo University (OAU), Nigeria

Background

Bats (Chiroptera) are one of the most diverse groups of mammals which carry out important ecological and agricultural functions that are beneficial to humans. However, they are increasingly recognized as natural vectors for a number of zoonotic pathogens and favourable hosts for zoonotic infections. Large populations of the Straw-Coloured Fruit Bat (Eidolon helvum) colonize the main campus of the Obafemi Awolowo University (OAU), Ile-Ife, Nigeria, but the public health implications of faecal contamination and pollution by these flying mammals is unknown. This study characterized S. aureus obtained from faecal samples of these migratory mammals with a view to determining the clonal types of the isolates, and to investigate the possibility of these flying animals as potential reservoir for zoonotic S. aureus infections.

Results

One hundred and seven (107) S. aureus isolates were recovered from 560 faecal samples in eleven roosting sites from January 2008 to February 2010. A large proportion of the isolates were susceptible to antibiotics, and molecular characterization of 70 isolates showed that 65 (92.9%) were assigned in coagulase type VI, while accessory gene typing classified 69 isolates into the following: type I (12; 17.1%), type II (3; 4.3%), type III (1; 1.4%) and type IV (53; 75.7%). On the whole, the isolates were grouped in five (A-E) main genotypes. Of the ten representative isolates selected for multilocus sequence typing (MLST), nine isolates were assigned with new sequence types: ST1725, ST1726, ST1727, ST2463-ST2467 and ST2470. Phylogenetic analysis provided evidence that S. aureus isolates in group C were closely related with ST1822 and associated clones identified in African monkeys, and group D isolates with ST75, ST883 and ST1223. The two groups exhibited remarkable genetic diversity compared to the major S. aureus clade.

Conclusions

Antibiotic resistance in faecal S. aureus isolates of E. helvum is low and multiple unique S. aureus lineages co-existed with E. helvum. The Straw-Coloured Fruit Bat in Ile-Ife, Nigeria is colonized predominantly by ST1725, ST1726, ST2463 and ST2470 with distinct genotypic characteristics that are rarely found in humans. This study has demonstrated on the possible existence of a reservoir of indigenous and anciently-divergent S. aureus clones among mammals in Africa.

Outbreak of yersiniosis in Egyptian rousette bats (Rousettus aegyptiacus) caused by Yersinia pseudotuberculosis serotype 4b

This report describes an outbreak of yersiniosis in Egyptian rousette bats (Rousettus aegyptiacus) caused by Yersinia pseudotuberculosis serotype 4b. Twelve of 61 bats died between November and December 2008 or in May 2009. The bats often displayed multiple yellow-white nodules in the spleen and liver. Microscopically, these consisted of focal necrosis accompanied by inflammatory cell infiltration and colonies of gram-negative bacilli. The bacterial colonies were identified immunohistochemically as Y. pseudotuberculosis O4 and Y. pseudotuberculosis serotype 4b was identified by bacteriological examination. Polymerase chain reaction demonstrated that the isolate harboured the virulence genes virF, inv and ypmA. YPMa is as a superantigenic toxin that is associated with acute systemic infection in man and may contribute to the virulence of Y. pseudotuberculosis in bats.

Bats and bacterial pathogens: a review

The occurrence of emerging infectious diseases and their relevance to human health has increased the interest in bats as potential reservoir hosts and vectors of zoonotic pathogens. But while previous and ongoing research activities predominantly focused on viral agents, the prevalence of pathogenic bacteria in bats and their impact on bat mortality have largely neglected. Enteric pathogens found in bats are often considered to originate from the bats' diet and foraging habitats, despite the fact that little is known about the actual ecological context or even transmission cycles involving bats, humans and other animals like pets and livestock. For some bacterial pathogens common in human and animal diseases (e.g. Pasteurella, Salmonella, Escherichia and Yersinia spp.), the pathogenic potential has been confirmed for bats. Other bacterial pathogens (e.g. Bartonella, Borrelia and Leptospira spp.) provide evidence for novel species that seem to be specific for bat hosts but might also be of disease importance in humans and other animals. The purpose of this review is to summarize the current knowledge of bacterial pathogens identified in bats and to consider factors that might influence the exposure and susceptibility of bats to bacterial infection but could also affect bacterial transmission rates between bats, humans and other animals.

Diseases and causes of death in European bats: dynamics in disease susceptibility and infection rates

BACKGROUND

Bats receive increasing attention in infectious disease studies, because of their well recognized status as reservoir species for various infectious agents. This is even more important, as bats with their capability of long distance dispersal and complex social structures are unique in the way microbes could be spread by these mammalian species. Nevertheless, infection studies in bats are predominantly limited to the identification of specific pathogens presenting a potential health threat to humans. But the impact of infectious agents on the individual host and their importance on bat mortality is largely unknown and has been neglected in most studies published to date.

METHODOLOGY/PRINCIPAL FINDINGS

Between 2002 and 2009, 486 deceased bats of 19 European species (family Vespertilionidae) were collected in different geographic regions in Germany. Most animals represented individual cases that have been incidentally found close to roosting sites or near human habitation in urban and urban-like environments. The bat carcasses were subjected to a post-mortem examination and investigated histo-pathologically, bacteriologically and virologically. Trauma and disease represented the most important causes of death in these bats. Comparative analysis of pathological findings and microbiological results show that microbial agents indeed have an impact on bats succumbing to infectious diseases, with fatal bacterial, viral and parasitic infections found in at least 12% of the bats investigated.

CONCLUSIONS/SIGNIFICANCE

Our data demonstrate the importance of diseases and infectious agents as cause of death in European bat species. The clear seasonal and individual variations in disease prevalence and infection rates indicate that maternity colonies are more susceptible to infectious agents, underlining the possible important role of host physiology, immunity and roosting behavior as risk factors for infection of bats.

Diseases in free-ranging bats from Germany

BACKGROUND

The emergence of important viral diseases and their potential threat to humans has increased the interest in bats as potential reservoir species. Whereas the majority of studies determined the occurrence of specific zoonotic agents in chiropteran species, little is known about actual bat pathogens and impacts of disease on bat mortality. Combined pathological and microbiological investigations in free-ranging bats are sparse and often limited by small sample sizes. In the present study about 500 deceased bats of 19 European species (family Vespertilionidae) were subjected to a post-mortem examination followed by histo-pathological and bacteriological investigations. The bat carcasses originated from different geographical regions in Germany and were collected by bat researchers and bat rehabilitation centers.

RESULTS

Pathological examination revealed inflammatory lesions in more than half of the investigated bats. Lung was the predominantly affected organ (40%) irrespective of bat species, sex and age. To a lesser extent non-inflammatory organ tissue changes were observed. Comparative analysis of histo-pathology and bacteriology results identified 22 different bacterial species that were clearly associated with pathological lesions. Besides disease-related mortality, traumatic injuries represented an additional major cause of death. Here, attacks by domestic cats accounted for almost a half of these cases.

CONCLUSIONS

The present study shows that free-ranging bats not only serve as a reservoir of infectious agents, they are also vulnerable to various infectious diseases. Some of these microbial agents have zoonotic potential, but there is no evidence that European bats would pose a higher health hazard risk to humans in comparison to other wildlife.

Pathogenesis of Y. enterocolitica and Y. pseudotuberculosis in Human Yersiniosis

Yersiniosis is a food-borne illness that has become more prevalent in recent years due to human transmission via the fecal-oral route and prevalence in farm animals. Yersiniosis is primarily caused by Yersinia enterocolitica and less frequently by Yersinia pseudotuberculosis. Infection is usually characterized by a self-limiting acute infection beginning in the intestine and spreading to the mesenteric lymph nodes. However, more serious infections and chronic conditions can also occur, particularly in immunocompromised individuals. Y. enterocolitica and Y. pseudotuberculosis are both heterogeneous organisms that vary considerably in their degrees of pathogenicity, although some generalizations can be ascribed to pathogenic variants. Adhesion molecules and a type III secretion system are critical for the establishment and progression of infection. Additionally, host innate and adaptive immune responses are both required for yersiniae clearance. Despite the ubiquity of enteric Yersinia species and their association as important causes of food poisoning world-wide, few national enteric pathogen surveillance programs include the yersiniae as notifiable pathogens. Moreover, no standard exists whereby identification and reporting systems can be effectively compared and global trends developed. This review discusses yersinial virulence factors, mechanisms of infection, and host responses in addition to the current state of surveillance, detection, and prevention of yersiniosis.