Tetratrichomonas and Trichomonas spp.-Associated Disease in Free-Ranging Common Eiders (Somateria mollissima) from Wellfleet Bay, MA and Description of ITS1 Region Genotypes

During an outbreak of Wellfleet Bay virus (WFBV) in common eiders (Somateria mollissima) from the Cape Cod region of Massachusetts, several birds were diagnosed with trichomonosis consisting of multiple trichomonad species. Six birds were examined, with trichomonads found in ceca in four birds and associated typhlitis in three of these four birds. PCR and DNA sequencing utilizing trichomonad-specific primers targeting the ITS1 region of the ribosomal DNA (rDNA) revealed the presence of Tetratrichomonas gallinarum in the gastrointestinal tracts of five birds and Trichomonas spp. in the livers of two birds, one of which had a dual Te. gallinarum-Trichomonas gallinae infection. Sequence analysis revealed no variation between Te. gallinarum sequences whereas the ITS1 sequences obtained from the other Trichomonas spp. demonstrated the presence of multiple genotypes. One sequence had 100% identity to a Trichomonas sp. previously isolated from a Cooper\u27s hawk (Accipiter cooperii) and the other sequence was 100% identical to a previously described Tr. gallinae isolate obtained from a Pacific Coast band-tailed pigeon (Patagioenas fasciata monilis). These findings suggest Te. gallinarum and other Trichomonas spp. possibly contributed to morbidity and mortality in this species. Furthermore, to the authors\u27 knowledge, this is the first report of trichomonad-associated disease in a free-ranging sea duck

Epidemiology of the lymphatic-dwelling filarioid nematode Rumenfilaria andersoni in free-ranging moose (Alces alces) and other cervids of North America

Background: Moose (Alces alces) are a culturally and economically valued species in Minnesota, where the northeast population has decreased by 60 % since 2006. The cause of the decline is currently unclear; however, parasites, predation, and climate change have all been implicated. Nematode parasites are important pathogens in North American moose, potentially causing severe disease and mortality. Recent spread of Rumenfilaria andersoni, a filarioid nematode of moose, has been documented in Finnish cervids; however, little is known about the epidemiology of this parasite in North America. Methods: To investigate the prevalence and distribution of R. andersoni, 584 blood samples were collected from live-captured and dead animals and screened microscopically for the presence of microfilariae using a modified Knott's test. Microfilariae were identified based on morphological characteristics. A subset of Knott's-positive animals was subjected to polymerase chain reaction (PCR) with filarioid-specific primers targeting the first internal transcribed spacer region (ITS-1) of the rRNA gene cluster. Results: Rumenfilaria microfilariae were present in 20.5 % of Minnesota moose (n = 352), with slight fluctuations observed over four years. Minnesota white-tailed deer (Odocoileus virginianus) (n = 2) and moose (n = 44) from Alaska, Montana, Washington, Maine, and New Hampshire also harbored R. andersoni, suggesting this parasite occurs widely throughout North American moose herds, and white-tailed deer can serve as a patent host. Sequence analysis of cervid blood (moose, n = 15; white-tailed deer, n = 1) confirmed the identity of R. andersoni and revealed the existence of two distinct clades. Genetic comparisons of R. andersoni isolates from North America and semi-domesticated Finnish reindeer found the two groups to be closely related, supporting previous hypotheses that R. andersoni was recently introduced into Finland by the importation of deer from the United States. Conclusions: To the best of our knowledge these observations represent the first report of R. andersoni within the contiguous United States and reveal this nematode as a common parasite of North American moose and white-tailed deer. Although the implications of R. andersoni infection on moose health is unclear, increased awareness of this parasite will help prevent unintentional introduction of R. andersoni into naive populations via the translocation of wild and captive cervids.Peer reviewe

Emergence of the arterial worm Elaeophora schneideri in moose (Alces alces) and tabanid fly vectors in northeastern Minnesota, USA

Background Moose (Alces alces) are a culturally and economically valued species in Minnesota. However, the moose population has experienced a sudden, marked decline in their range, including extirpation in the northwest and a 66% decline in the last decade in the northeast portions of the state. Although the exact cause of this decline is unclear, parasitic metastrongylid and filarioid nematode infections are known causes of morbidity and mortality in moose across North America. Methods To determine if these parasitic nematodes could be contributing to the Minnesota moose population decline, we molecularly examined banked tissues obtained from moose that died of known and unknown causes for the presence of nematode DNA. Extracted brain DNA of 34 individual moose was amplified utilizing primers targeting the 18S rRNA gene and internal transcribed spacer regions of nematodes. Results DNA sequencing revealed that PCR products obtained from 15 (44.1%) of the moose were 99% identical to Parelaphostrongylus tenuis, a metastrongylid known to cause neurological disease and death. Additionally, brain tissue from 20 (58.8%) individuals yielded sequences that most closely aligned with Elaeophora schneideri, a parasite associated with neurological impairment but previously unreported in Minnesota. Setaria yehi, a common filarioid parasite of deer, was also detected in the brain tissue of 5 (14.7%) moose. Molecular screening of 618 captured tabanid flies from four trapping sites revealed E. schneideri was present (6%) in the Minnesota environment and transmission could occur locally. Prevalence rates among the flies ranged between 0–100% per trapping site, with Chrysops spp. and Hybomitra spp. implicated as the vectors. Conclusions Ultimately, these data confirm that P. tenuis is widespread in the Minnesota moose population and raises the question of the significance of E. schneideri as a contributing factor to morbidity and mortality in moose

Manganese Detoxification by MntE Is Critical for Resistance to Oxidative Stress and Virulence of Staphylococcus aureus

Manganese (Mn) is generally viewed as a critical nutrient that is beneficial to pathogenic bacteria due to its function as an enzymatic cofactor and its capability of acting as an antioxidant; yet paradoxically, high concentrations of this transition metal can be toxic. In this work, we demonstrate Staphylococcus aureus utilizes the cation diffusion facilitator (CDF) family protein MntE to alleviate Mn toxicity through efflux of excess Mn. Inactivation of mntE leads to a significant reduction in S. aureus resistance to oxidative stress and S. aureus-mediated mortality within a mouse model of systemic infection. These results highlight the importance of MntE-mediated Mn detoxification in intracellular Mn homeostasis, resistance to oxidative stress, and S. aureus virulence. Therefore, this establishes MntE as a potential target for development of anti-S. aureus therapeutics.Manganese (Mn) is an essential micronutrient critical for the pathogenesis of Staphylococcus aureus, a significant cause of human morbidity and mortality. Paradoxically, excess Mn is toxic; therefore, maintenance of intracellular Mn homeostasis is required for survival. Here we describe a Mn exporter in S. aureus, MntE, which is a member of the cation diffusion facilitator (CDF) protein family and conserved among Gram-positive pathogens. Upregulation of mntE transcription in response to excess Mn is dependent on the presence of MntR, a transcriptional repressor of the mntABC Mn uptake system. Inactivation of mntE or mntR leads to reduced growth in media supplemented with Mn, demonstrating MntE is required for detoxification of excess Mn. Inactivation of mntE results in elevated levels of intracellular Mn, but reduced intracellular iron (Fe) levels, supporting the hypothesis that MntE functions as a Mn efflux pump and Mn efflux influences Fe homeostasis. Strains inactivated for mntE are more sensitive to the oxidants NaOCl and paraquat, indicating Mn homeostasis is critical for resisting oxidative stress. Furthermore, mntE and mntR are required for full virulence of S. aureus during infection, suggesting S. aureus experiences Mn toxicity in vivo. Combined, these data support a model in which MntR controls Mn homeostasis by balancing transcriptional repression of mntABC and induction of mntE, both of which are critical for S. aureus pathogenesis. Thus, Mn efflux contributes to bacterial survival and virulence during infection, establishing MntE as a potential antimicrobial target and expanding our understanding of Mn homeostasis

Staphylococcus aureus HemX Modulates Glutamyl-tRNA Reductase Abundance To Regulate Heme Biosynthesis

Staphylococcus aureus is responsible for a significant amount of devastating disease. Its ability to colonize the host and cause infection is supported by a variety of proteins that are dependent on the cofactor heme. Heme is a porphyrin used broadly across kingdoms and is synthesized de novo from common cellular precursors and iron. While heme is critical to bacterial physiology, it is also toxic in high concentrations, requiring that organisms encode regulatory processes to control heme homeostasis. In this work, we describe a posttranscriptional regulatory strategy in S. aureus heme biosynthesis. The first committed enzyme in the S. aureus heme biosynthetic pathway, glutamyl-tRNA reductase (GtrR), is regulated by heme abundance and the integral membrane protein HemX. GtrR abundance increases dramatically in response to heme deficiency, suggesting a mechanism by which S. aureus responds to the need to increase heme synthesis. Additionally, HemX is required to maintain low levels of GtrR in heme-proficient cells, and inactivation of hemX leads to increased heme synthesis. Excess heme synthesis in a ΔhemX mutant activates the staphylococcal heme stress response, suggesting that regulation of heme synthesis is critical to reduce self-imposed heme toxicity. Analysis of diverse organisms indicates that HemX is widely conserved among heme-synthesizing bacteria, suggesting that HemX is a common factor involved in the regulation of GtrR abundance. Together, this work demonstrates that S. aureus regulates heme synthesis by modulating GtrR abundance in response to heme deficiency and through the activity of the broadly conserved HemX

Visualizing Staphylococcus aureus pathogenic membrane modification within the host infection environment by multimodal imaging mass spectrometry

Bacterial pathogens have evolved virulence factors to colonize, replicate, and disseminate within the vertebrate host. Although there is an expanding body of literature describing how bacterial pathogens regulate their virulence repertoire in response to environmental signals, it is challenging to directly visualize virulence response within the host tissue microenvironment. Multimodal imaging approaches enable visualization of host-pathogen molecular interactions. Here we demonstrate multimodal integration of high spatial resolution imaging mass spectrometry and microscopy to visualize Staphylococcus aureus envelope modifications within infected murine and human tissues. Data-driven image fusion of fluorescent bacterial reporters and matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance imaging mass spectrometry uncovered S. aureus lysyl-phosphatidylglycerol lipids, localizing to select bacterial communities within infected tissue. Absence of lysyl-phosphatidylglycerols is associated with decreased pathogenicity during vertebrate colonization as these lipids provide protection against the innate immune system. The presence of distinct staphylococcal lysyl-phosphatidylglycerol distributions within murine and human infections suggests a heterogeneous, spatially oriented microbial response to host defenses.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Raf Van de Pla

MALDI Iron 10 Day

These data represent MALDI IMS data of biological replicates of mice infected with S. aureus 10 days post infection. This particular strain of S. aureus has been modified with a fluorescent reporter sensitive to iron deplete conditions. Three biological replicates are tested here

MALDI Iron 4 Day

These data represent MALDI IMS data of biological replicates of mice infected with S. aureus 4 days post infection. This particular strain of S. aureus has been modified with a fluorescent reporter sensitive to iron deplete conditions. Three biological replicates are tested here

MALDI 3D Volume

These data are MALDI IMS data from a 3D mouse kidney infected with S. aureus. These were collected using a SimulTOF mass spectrometer