Opportunistic Microbes Research Articles

Патогенетические аспекты терапии воспалительных заболеваний урогенитального тракта у женщин репродуктивного возраста

This paper discusses one of the important gynecological issues, inflammatory diseases of the urogenital tract caused by opportunistic microbes. The treatment and long-term control over these conditions are challenging and depend on their occurrence and high risk of complications. Impaired local anti-infectious protection is one of the risk factors of chronic inflammation. Since the disease may recur even after successful treatment, domestic and foreign authors increasingly focus on immunotherapy as a part of complex strategy and isolated entity. Local immunotherapy may prevent recurrences and activate host defense. This paper describes the management of two women with mixed infections. The first woman with chronic recurrent inflammation (cervicitis caused by U. urealyticum, vulvovaginal candidiasis, and aerobic vaginitis) in whom prior etiological therapy was ineffective received immunotherapy which resulted in long-term remission. The second woman with coexistent papillomavirus infection (genital warts) and bacterial vaginosis received immunotherapy and topical etiological treatment. As a result, clinical symptoms, the size and number of genital warts reduced which greatly facilitated their chemical destruction. KEYWORDS: genital tract, urogenital infections, papillomavirus infection, bacterial vaginosis, local immunity, biofilms. FOR CITATION: Letyaeva O.I., Ziganshin O.R. Pathogenic treatment of the inflammatory diseases of the urogenital tract in women of reproductive age. Russian Journal of Woman and Child Health. 2021;4(1):59–64. DOI: 10.32364/2618-8430-2021-4-1-59-64.

Evidence of potent antibacterial effect of fermented papaya leaf against opportunistic skin pathogenic microbes

The papaya leaf juice has been long practised as a traditional remedy to cure ailments due to its medicinal properties. The objective of this research is to study the effectiveness of fermented papaya leaf to inhibit the growth of pathogenic bacteria and yeast: Staphylococcus aureus, Pseudomonas aeruginosa, Propionibacterium acnes and Candida albicans. The efficacy of fermented papaya leaf against selected pathogenic microbes was evaluated using agar well diffusion assay, broth microdilution assay and time-kill test. Evidence from data collected confirmed that fermented papaya leaf supernatant showed more pronounced antibacterial and antifungal effect than papaya leaf alone. Generally, fermented papaya leaf supernatant demonstrated potent antimicrobial effect against all bacterial pathogens tested particularly P. aeruginosa followed by P. acne and S. aureus. However, it was found that fermented papaya leaf was less effective against Candida albicans. It needs 4- to 7-folds higher concentration to inhibit 50% C. albicans growth than the bacteria. The antibacterial compounds produced in the supernatant appeared to have some bactericidal effect against P. aeruginosa, P. acne and S. aureus with the minimum inhibitory concentration (MIC>99) of 16%, 50% and 60%, respectively. Particularly, the fermented papaya leaf supernatant at 60% concentration showed 100% inhibition rate within 30 mins against P. aeruginosa. However, it needs a longer time to show the same inhibition effect against S. aureus and P. acne, which was about 2-6 h. The potent killing effect of fermented papaya leaf showed a potential use in skincare application to control pathogenic microbe infection

Microbiological aspects in conservative treatment of generalized periodontitis using autotrombocytic mass

The primary factor causing periodontal damage is plaque bacteria. The etiological structure of infectious processes in the last decade has changed significantly, due to the constant evolution of microbes and the involvement of opportunistic microbes in the pathological process, which can act as commensals in the normal microflora and manifest their pathogenicity with a decrease in the body's immune status. Inflammatory processes in the oral cavity are sometimes an endogenous infection caused by the resident flora of not only the oral cavity, but also other ecosystems of the body.

Formicine ants swallow their highly acidic poison for gut microbial selection and control.

Animals continuously encounter microorganisms that are essential for health or cause disease. They are thus challenged to control harmful microbes while allowing the acquisition of beneficial microbes. This challenge is likely especially important for social insects with respect to microbes in food, as they often store food and exchange food among colony members. Here we show that formicine ants actively swallow their antimicrobial, highly acidic poison gland secretion. The ensuing acidic environment in the stomach, the crop, can limit the establishment of pathogenic and opportunistic microbes ingested with food and improve the survival of ants when faced with pathogen contaminated food. At the same time, crop acidity selectively allows acquisition and colonization by Acetobacteraceae, known bacterial gut associates of formicine ants. This suggests that swallowing of the poison in formicine ants acts as a microbial filter and that antimicrobials have a potentially widespread but so far underappreciated dual role in host-microbe interactions.

Mussismilia braziliensis White Plague Disease Is Characterized by an Affected Coral Immune System and Dysbiosis.

Infectious diseases are one of the major drivers of coral reef decline worldwide. White plague-like disease (WPL) is a widespread disease with a complex etiology that infects several coral species, including the Brazilian endemic species Mussismilia braziliensis. Gene expression profiles of healthy and WPL-affected M. braziliensis were analyzed in winter and summer seasons. The de novo assembly of the M. braziliensis transcriptome from healthy and white plague samples produced a reference transcriptome containing 119,088 transcripts. WPL-diseased samples were characterized by repression of immune system and cellular defense processes. Autophagy and cellular adhesion transcripts were also repressed in WPL samples, suggesting exhaustion of the coral host defenses. Seasonal variation leads to plasticity in transcription with upregulation of intracellular signal transduction, apoptosis regulation, and oocyte development in the summer. Analysis of the active bacterial rRNA indicated that Pantoea bacteria were more abundant in WPL corals, while Tistlia, Fulvivirga, and Gammaproteobacteria Ga0077536 were more abundant in healthy samples. Cyanobacteria proliferation was also observed in WPL, mostly in the winter. These results indicate a scenario of dysbiosis in WPL-affected M. braziliensis, with the loss of potentially symbiotic bacteria and proliferation of opportunistic microbes after the start of the infection process.

Recognition of Candida albicans and Role of Innate Type 17 Immunity in Oral Candidiasis.

Candida albicans is an opportunistic pathogenic fungus considered to be a common member of the human microflora. Similar to some other opportunistic microbes, C. albicans can invade and benefit from its host when the immune status of that host is weakened. Most often this happens to immunocompromised individuals, leading to the infection of oral and vaginal mucosae or the systemic spread of the pathogen throughout the entire body. Oropharyngeal candidiasis (OPC) occurs in up to 90 percent of patients with acquired immunodeficiency syndrome (AIDS), making it the most frequent opportunistic infection for this group. Upon first signs of fungal invasion, a range of host signaling activates in order to eliminate the threat. Epithelial and myeloid type cells detect C. albicans mainly through receptor tyrosine kinases and pattern-recognition receptors. This review provides an overview of downstream signaling resulting in an adequate immune response through the activation of various transcription factors. The study discusses recent advances in research of the interleukin-17 (IL-17) producing innate cells, including natural T helper 17 (nTh17) cells, γδ T cells, invariant natural killer T (iNKT) cells and type 3 innate lymphoid cells (ILC3) that are involved in response to oral C. albicans infections.

Propolis Envelope Promotes Beneficial Bacteria in the Honey Bee (Apis mellifera) Mouthpart Microbiome.

Honey bees collect and apply plant resins to the interior of their nest cavity, in order to form a layer around the nest cavity called a propolis envelope. Propolis displays antimicrobial activity against honey bee pathogens, but the effect of propolis on the honey bee microbiome is unknown. Honey bees do not intentionally consume propolis, but they do manipulate propolis with their mouthparts. Because honey bee mouthparts are used for collecting and storing nectar and pollen, grooming and trophallaxis between adults, feeding larvae, and cleaning the colony, they are an important interface between the bees’ external and internal environments and serve as a transmission route for core gut bacteria and pathogens alike. We hypothesized that the antimicrobial activity of an experimentally applied propolis envelope would influence the bacterial diversity and abundance of the worker mouthpart microbiome. The results revealed that the mouthparts of worker bees in colonies with a propolis envelope exhibited a significantly lower bacterial diversity and significantly higher bacterial abundance compared to the mouthparts of bees in colonies without a propolis envelope. Based on the taxonomic results, the propolis envelope appeared to reduce pathogenic or opportunistic microbes and promote the proliferation of putatively beneficial microbes on the honey bee mouthparts, thus reinforcing the core microbiome of the mouthpart niche.

Two enigmas may solve each other: the oocyte coat and atresia in the common cockle, Cerastoderma edule (Linnaeus, 1758)

Two co-occurring, enigmatic aspects of bivalve reproduction were investigated in the common cockle Cerastoderma edule: the oocyte coat and oocyte atresia. Qualitative histology and transmission electron microscopy (TEM) of cockles collected on the French Atlantic coast revealed not only the fine structure of the oocyte coat, but also confirmed that it is secreted by the oocyte itself and composed of acid mucopolysaccharides (AMPS), known to be viscous and adhesive. Quantitative histology showed that at the peak of oogenesis, oocyte coats occupy the largest fraction (approx. 40%) of the gonad acinal volume, representing both a significant sacrifice of female gamete capacity, and a non-gamete energetic investment. Potential benefits of the coat include protection from mechanical abrasion, predation, and opportunistic microbes. Atresia (oocyte degeneration) was a known second source of reduced fecundity, with a minimum impact of approximately 50% of the total oocyte volume. It is suggested that this high proportion of atresic oocytes is related to the previously-documented genetic inviability of early post-fertilization life stages. The qualitative histological and TEM observations revealed atresic debris adhering to the exterior surface of the oocyte coats. Such an arrangement would isolate adjacent oocyte coats, enabling the oocytes to be spawned individually, rather than as an egg mass, and therefore to undergo planktonic development and dispersion. Oocyte atresia and the oocyte coat of Cerastoderma edule therefore appear to be linked in the first indication of an adaptive function in bivalves.

A role of oropharyngeal microbiota in developing acute and chronic diseases of the upper respiratory tract

Currently, a rise in incidence of polyethological inflammation of the upper respiratory tract mucosa paralleled by altered resident and transient microbiota displaying in many cases increased antibiotic resistance has been noted. Opportunistic microbes play a major role in developing inflammatory process in Pirogov–Waldeyer’s ring. An inflammatory process occurring in the tonsillar lymphatic tissue results in host systemic complications. Fighting against acute and chronic infections of the upper respiratory tract holds the main task in pediatric otorhinolaryngology, as they can consequently elicit the cardiovascular, genitourinary and musculoskeletal complications. The results of studies examining this issue remain very contradictory, which accounted for a need to conduct our study on the territory of Moldova featured with mixed climatic conditions. Here, we wanted to study a role of microbial factor in etiopathogenesis of chronic tonsillitis in children. Bacteriological microbiota data for superficial palatine tonsils were obtained form 608 children subdivided into 5 groups: group I — 333 children with compensated chronic tonsillitis; group II — 87 children with decompensated chronic tonsillitis; group III — 91 children with acute upper respiratory tract infections (comparison group); group IV — 48 children with acute upper respiratory tract infections treated with antibiotic therapy; group V — 49 apparently healthy children (control group). It was found that β-hemolytic streptococcus exerting high sensitivity to virtually all antibiotics groups was detected in 17.4% of children with acute tonsilar inflammatory processes and decompensated defense in the lymphatic pharyngeal ring compared to 3.5% in control group. Streptococcus pneumoniae was isolated in all study groups ranging within 4.8–21.7%, including 14% in apparently healthy children characterized by reduced antibiotics sensitivity. The data obtained suggest that sickly children with acute and chronic upper respiratory tract infections constitute a risk group for developing somatic diseases. The high incidence of Streptococcus pneumoniae indicates a need for performing immunoprophylaxis, use of therapeutic vaccination as a up-to-date, combined approach in treatment of such pediatric cohort.

Differentiation of Francisella tularensis Subspecies and Subtypes.

The highly infectious and zoonotic pathogen Francisella tularensis is the etiologic agent of tularemia, a potentially fatal disease if untreated. Despite the high average nucleotide identity, which is >99.2% for the virulent subspecies and >98% for all four subspecies, including the opportunistic microbe Francisella tularensis subsp. novicida, there are considerable differences in genetic organization. These chromosomal disparities contribute to the substantial differences in virulence observed between the various F. tularensis subspecies and subtypes. The methods currently available to genotype F. tularensis cannot conclusively identify the associated subpopulation without using time-consuming testing or complex scoring matrices. To address this need, we developed both single and multiplex quantitative real-time PCR (qPCR) assays that can accurately detect and identify the hypervirulent F. tularensis subsp. tularensis subtype A.I, the virulent F. tularensis subsp. tularensis subtype A.II, F. tularensis subsp. holarctica (also referred to as type B), and F. tularensis subsp. mediasiatica, as well as opportunistic F. tularensis subsp. novicida from each other and near neighbors, such as Francisella philomiragia, Francisella persica, and Francisella-like endosymbionts found in ticks. These fluorescence-based singleplex and non-matrix scoring multiplex qPCR assays utilize a hydrolysis probe, providing sensitive and specific F. tularensis subspecies and subtype identification in a rapid manner. Furthermore, sequencing of the amplified F. tularensis targets provides clade confirmation and informative strain-specific details. Application of these qPCR- and sequencing-based detection assays will provide an improved capability for molecular typing and clinical diagnostics, as well as facilitate the accurate identification and differentiation of F. tularensis subpopulations during epidemiological investigations of tularemia source outbreaks.

Female immunity in response to sexually transmitted opportunistic bacteria in the common bedbug Cimex lectularius

Besides typical sexually transmitted microbes, even environmental, opportunistic microbes have been found in copulatory organs of insects and even humans. To date, only one study has experimentally investigated the sexual transmission of opportunistic microbes from male to female insects, whereas nothing is known about the transmission from females to males. Even if opportunistic microbes do not cause infection upon transmission, they might eventually become harmful if they multiply inside the female. While the immune system of females is often assumed to target sexually transmitted microbes, most studies ignore the role of mating-associated opportunistic microbes. Variation in immunity between populations has been linked to parasite or bacteria prevalence but no study has ever addressed between-population differences in immune responses to sexually transmitted opportunistic microbes. We here show that bacteria applied to the copulatory organs of common bedbugs, Cimex lectularius, are sexually transmitted to the opposite sex at a high rate, including the transmission from female to male. Bacterial growth in the female sperm-receiving organ was inhibited over the first hours after introduction, but after this initial inhibition bacterial numbers increased, suggesting a shift of investment from immune defence towards reproduction. However, 24 h after the injection of bacteria, male components, or saline as a control, the sperm-receiving organ showed lysozyme-like activity and inhibited the growth of Gram-negative and Gram-positive bacteria in vitro, potentially to mop up the remaining bacteria. Contrasting our prediction, neither bacterial growth nor immune responses differed between populations. Future studies should link transmission dynamics, immune responses and fitness effects in both sexes. Experimental manipulation of environmental bacteria could be used to investigate how transmission frequency and toxicity of sexually transmitted opportunistic microbes shapes bacteria clearance and immune responses across populations.

Evaluation of heterotrophic bacteria associated with healthy and bleached corals of Gulf of Kutch, Gujarat, India for siderophore production and their response to climate change factors

Abstract Bacteria are known to play a crucial role in coral health but their mechanisms are unclear. Siderophore production could be one of the mechanisms by which they benefit or harm the corals. Bacteria produce siderophore to adapt in harsh conditions, such as nutrient limiting and competing environments such as coral surface. In the present study, siderophore producing ability of microbes associated with healthy and bleached corals is evaluated as both healthy and bleached coral surface provide a different environment concerning nutrients and competitions. Total of 129 siderophore-producing bacteria associated with two healthy (n = 66 isolates) and bleached coral (n = 63) species (Porites spp. and Turbinaria spp.) from the Gulf of Kutch (GoK), Gujarat (India) are screened and compared. No relation between coral health status and siderophore producing ability of microbes is observed (one-way ANOVA, p = 0.67). All the isolates are positive to catecholate type of siderophore which has the strongest affinity for limiting iron. The study also explores the growth and siderophore production behavior of healthy and bleached coral isolates at decreasing pH and temperature rise as they are the important factors that affects the solubility of nutrients and thus, the structure and functioning of the microbes. Isolates from bleached corals showed an increase in growth even at pH 6, whereas the growth of healthy coral isolates reduces at pH 6. Temperature rise is negatively correlated to growth and siderophore production by all isolates except Bacillus sp. PH26. Combined low pH and temperature rise stress, negatively affect growth and siderophore production of coral-associated microbes with Bacillus sp. PH26 as exception. General correlation trend of bacterial growth and siderophore production is positive. The isolates showing exceptional behavior might be possibly beneficial or harmful to the coral health. Thus, growth and siderophore production of microbes under changing climate conditions might be used as preliminary tools to screen beneficial and pathogenic microbes of corals from opportunistic microbes. This screening would reduce the number of possible candidates for in-situ and in-vitro microcosm experiments to understand the role of siderophore producing microbes in coral health. Overall, pH and temperature have a significant impact on coral-associated microbial growth and siderophore production, which ultimately impact the coral health and disease as the microbes form an integral part of coral holobiont. The study laid the foundation for future studies to understand the role of siderophore producing bacteria in coral health in the global climate-changing era.

Response to mechanical loading in rat Achilles tendon healing is influenced by the microbiome

We have previously shown that changes in the microbiome influence how the healing tendon responds to different treatments. The aim of this study was to investigate if changes in the microbiome influence the response to mechanical loading during tendon healing. 90 Sprague-Dawley rats were used. Specific Opportunist and Pathogen Free (SOPF) rats were co-housed with Specific Pathogen Free (SPF) rats, carrying Staphylococcus aureus and other opportunistic microbes. After 6 weeks of co-housing, the SOPF rats were contaminated which was confirmed by Staphylococcus aureus growth. Clean SOPF rats were used as controls. The rats were randomized to full loading or partial unloading by Botox injections in their calf muscles followed by complete Achilles tendon transection. Eight days later, the healing tendons were tested mechanically. The results were analysed by a 2-way ANOVA with interaction between loading and contamination on peak force as the primary outcome and there was an interaction for both peak force (p = 0.049) and stiffness (p = 0.033). Furthermore, partial unloading had a profound effect on most outcome variables. In conclusion, the response to mechanical loading during tendon healing is influenced by changes in the microbiome. Studies aiming for clinical relevance should therefore consider the microbiome of laboratory animals.

A high biodiversity mitigates the impact of ocean acidification on hard-bottom ecosystems

Biodiversity loss and climate change simultaneously threaten marine ecosystems, yet their interactions remain largely unknown. Ocean acidification severely affects a wide variety of marine organisms and recent studies have predicted major impacts at the pH conditions expected for 2100. However, despite the renowned interdependence between biodiversity and ecosystem functioning, the hypothesis that the species’ response to ocean acidification could differ based on the biodiversity of the natural multispecies assemblages in which they live remains untested. Here, using experimentally controlled conditions, we investigated the impact of acidification on key habitat-forming organisms (including corals, sponges and macroalgae) and associated microbes in hard-bottom assemblages characterised by different biodiversity levels. Our results indicate that, at higher biodiversity, the impact of acidification on otherwise highly vulnerable key organisms can be reduced by 50 to >90%, depending on the species. Here we show that such a positive effect of a higher biodiversity can be associated with higher availability of food resources and healthy microbe-host associations, overall increasing host resistance to acidification, while contrasting harmful outbreaks of opportunistic microbes. Given the climate change scenarios predicted for the future, we conclude that biodiversity conservation of hard-bottom ecosystems is fundamental also for mitigating the impacts of ocean acidification.

Production of lumpfish (Cyclopterus lumpus L.) in RAS with distinct water treatments: Effects on fish survival, growth, gill health and microbial communities in rearing water and biofilm

Lumpfish (Cyclopterus lumpus L.) in Norway is currently produced in traditional flow-through systems (FTS). Hatcheries frequently show signs of bacterial infections, unstable microbial communities in the rearing water and varying mortality. Recirculating aquaculture systems (RAS) is proposed to create stable and healthy microbial environments, with less probabilities for blooming of opportunistic microbes. Studies have also shown that RAS increases the survival of marine fish. The aim with this study was to investigate the effect of various RAS water treatment designs on water and biofilm microbiota, survival, growth and gill health of lumpfish. An experiment with lumpfish was conducted, from 2 months post hatch to the transfer into sea cages. Five different water treatment regimens were compared: 1. RAS with no additional water treatment, 2. RAS with a filtration unit for removal of small particles, 3. RAS with filtration and disinfection with UV-irradiation, 4. RAS with filtration and disinfection with UV-irradiation and ozone and 5. FTS as a reference. The microbiota of the rearing water and tank wall biofilm were sampled and characterized by Illumina sequencing of 16S rDNA amplicons. Lumpfish juveniles reared in the RAS treatments were exposed to a more stable and diverse rearing water microbiota, with a lower share of opportunistic bacteria, a probable reason for the higher survival and better gill health of the fish compared to siblings reared in the FTS. Lumpfish reared in RAS without disinfection were exposed to a more diverse and stable water microbiota, with a lower share of opportunistic and potential harmful bacteria, compared to the lumpfish reared in RAS with disinfection and FTS. This resulted in better gill health. Fish in RAS with filtration, but no disinfection, had a better gill health than the fish in the RAS without filtration, possibly due to the reduction of small particles. The lumpfish were exposed to different microbial communities of both water and biofilm, due to the different treatments of the incoming tank water. In conclusion, our results indicate that implementation of RAS in the production of lumpfish has a potential to increase both survival, growth and gill health of the fish and that RAS with filtration of small particles, but without disinfection, result in the best fish health and performance among the investigated treatments.

Indigenous strains of lactobacilli as a basis for probiotics design

Lactobacilli are the most common microbes used in therapy and farm breeding. Their effectiveness and safety depend on species and strains of bacteria. In this investigation the most importance properties more than two hundred of Lactobacilli strains were studies. They were divided to the groups in dependence of their origin. The antagonistic activity between the members of different groups as well as between Lactobacilli and pathogens and opportunistic microbes were analyzed. It was found that the source of the bacteria determine the adhesive properties, bacterial antagonism and bacteriocins production.

Assessing efficiency of epidemiological security system for the medical organization

Healthcare workers comprise a high-risk cohort of developing diverse infections caused by opportunistic and pathogenic microbes. Among medical workers of the Russian Federation the first rank place in occupational diseases is held by tuberculosis of respiratory organs accounting for more than half of all registered occupational diseases. Moreover, its high incidence is particularly noted among forensic specialists and medical workers in anti-tuberculosis institutions. The organization of epidemiological surveillance and tuberculosis prevention medical workers so far remains unsolved both scientifically and practically. On one hand, high TB incidence in pattern of clinical TB forms may be due to higher percentage of patients suffering from common, advanced and complicated forms of drug-resistant Mycobacterium tuberculosis infection as well as rise of socially significant co-infections (HIV+tuberculosis) among the population. Specialists from the Regional Bureau of Forensic Medicine were examined during 2009–2018 time period by using molecular genetic approaches to analyze 4948 wash samples (2009–2013 — 3649 samples; 2014–2018 — 1299 swabs) collected from various environmental objects, medical overalls and hands of medical specialists while performing professional duties in autopsy rooms, laboratories as well as facilities housekeeping department. It was demonstrated that M. tuberculosis DNA was detected in 353 and 81 swabs in 2009–2013 and 2014–2018 time period. Based on intensity of contacting with pathogenic biological agents, production technologies applied in the Regional Bureau of Forensic Medicine were divided into two groups. M. tuberculosis contamination in diverse facilities or any item as well as a contamination risk for medical worker hands and medical overalls were evaluated in accordance with professional duties assigned to individual specialists, followed by calculating significant differences in groups exami ned. It was found that some facilities and environmental items most exposed to a high-risk M. tuberculosis contamination were identified, which are involved in pathogen spreading from autopsy rooms outside to the remainder of facilities. It allowed for autho rities to improve performance of activities ensuring epidemiological security for attending specia lists that not only resulted in significantly decreased incidence of M. tuberculosis DNA detection, but also lowered TB incidence rate among them from 292.4 down to 280.9 cases and 46.3 per 10 thousand workers during 2007–2009 and 2017–2018 time period, respectively.

Complex associations between cross‐kingdom microbial endophytes and host genotype in ash dieback disease dynamics

AbstractTree pathogens are a major threat to forest ecosystems. Conservation management strategies can exploit natural mechanisms of resistance, such as tree genotype and host‐associated microbial communities. However, fungal and bacterial communities are rarely looked at in the same framework, particularly in conjunction with host genotype. Here, we explore these relationships and their influence on ash dieback disease, caused by the pathogenHymenoscyphus fraxineus, in European common ash trees.We collected leaves from UK ash trees and used microsatellite markers to genotype trees, quantitative PCR to quantifyH. fraxineusinfection load and ITS and 16S rRNA amplicon sequencing to identify fungal and bacterial communities, respectively.There was a significant association betweenH. fraxineusinfection intensity and ash leaf fungal and bacterial community composition. Higher infection levels were positively correlated with fungal community alpha‐diversity, and a number of fungal and bacterial genera were significantly associated with infection presence and intensity. Under higher infection loads, leaf microbial networks were characterized by stronger associations between fewer members than those associated with lower infection levels. Together these results suggest thatH. fraxineusdisrupts stable endophyte communities after a particular infection threshold is reached, and may enable proliferation of opportunistic microbes. We identified three microbial genera associated with an absence of infection, potentially indicating an antagonistic relationship withH. fraxineusthat could be utilized in the development of anti‐pathogen treatments.Host genotype did not directly affect infection, but did significantly affect leaf fungal community composition. Thus, host genotype could have the potential to indirectly affect disease susceptibility through genotype × microbiome interactions, and should be considered when selectively breeding trees.Synthesis. We show that the diversity, composition and network structure of ash leaf microbial communities are associated with the severity of infection from ash dieback disease, with evidence of disease‐induced dysbiosis. We also show that host genotype influences leaf fungal community composition, but does not directly influence tree infection. These findings help to elucidate relationships between host genetics, the microbiome and a tree pathogen, highlighting potential resistance mechanisms and possible co‐infection concerns that could inform ash tree management.

Onychomycosis Caused by Malassezia pachydermatis in a Dog

Background: Malassezia species are commensal skin organisms of warm-blooded vertebrates that can act as opportunistic pathogens. Malassezia pachydermatis is of importance in both veterinary and human medicine. Recognised initially as causes of infection of the skin, they are now known to be superficial commensals as well as potential causes of infections in domestic animals and more serious human conditions such as fungemia. They have also been implicated in the pathogenesis of allergic and other inflammatory diseases. Onychomycosis is defined as fungal infection of the claw (nail disease) caused by dermatophytes (Microsporum and Trichophyton genus), non-dermatophyte molds (hyaline and dematiaceous) and/or yeasts. The objective of this work was to report a case of canine onychomycosis by Malassezia pachydermatis based on reference standard diagnostics of this pathology.Case: A 9-year-old male West Highland White Terrier presented history of claw abnormality: brown staining and partly brittle. The dog has no apparent history of trauma on the affected claw and no skin disease was reported. Direct examination of claw was performed using the tape strip technique revealed Malassezia organisms. Nail fragments were cultured onto Sabouraud Dextrose Agar with Chloramphenicol and Cycloheximide. After 10 days of incubation (32ºC) nail fragments allowed the isolation of pure colonies of Malassezia pachydermatis. The histopathological evaluation was performed by Sector of Veterinary Clinical Pathology, Faculdade de Veterinária (FAVET/UFRGS) and fungal infection due to Malassezia pachydermatis was confirmed by histopathologic examination (Hematoxylin and eosin and Grocott’s methenamine silver stain) of the nail, that revealed abundant yeasts (blastoconidia).Discussion: Fungal infection of the skin, hair and nails are common and are primary caused by the dermatophyte molds. Non-dermatophyte molds isolated from nails constitute a long list, but only a few species cause onychomycoses. These include Scopulariopsis brevicaulis, Fusarium sp., Acremonium spp., Aspergillus spp., Penicillium spp. Yeasts like Malassezia and Candida spp. are saprophytes and usually represent incidental contaminants associated with a non-sterile specimen at mycological culture, however in some cases they may parasite the nails and become an etiological agent of the disease. M. pachydermatis, normally present on the skin and in the ear canal of dogs and cats, can act as opportunistic pathogenic microbe and frequently causes dermatitis and otitis in mammals. In the case of onychomycosis, there is little evidence that Malassezia yeasts are implicated in nail plate invasion, although this may be a rare occurrence. All species of the genus are obligatory lipid-dependent forms, with the exception of M. pachydermatis, as well as absence of keratinolytic ability. Malassezia organisms were commonly retrieved from the subungual claw fold region of normal healthy dogs (should be considered resident microflora of the normal canine claw fold). Some authors suggests that high numbers of yeast can be detected on cytological evaluation of the skin surface of the canine claw fold from allergic dogs in both the absence and presence of concurrent signs of pruritus and paronychia.

Detection of coagulase-positive Staphylococcus and its antibiotics resistance profile, recovered from cattle carcasses of the state of Paraná, Brazil

Staphylococcus sp . is a commensal bacterium in humans. Nonetheless, it is considered as an opportunistic microbe, being frequently associated with food poisoning outbreaks and antimicrobial resistance. The purpose of this work was to evaluate the presence of coagulase-positive Staphylococcus sp. in 100 cattle carcasses slaughtered in a slaughterhouse in the northwestern region of Parana, Brazil, and to identify its in vitro resistance profile against different antimicrobials. Samples were collected through swabs from the slaughtered cattle carcasses, and then were forwarded to the Preventive Veterinary Medicine laboratory, at University of Parananese (UNIPAR). From the 100 samples, 18 (18%) recorded growth of microorganisms, and 16 samples of these were selected for the antimicrobial assay, according to the standard count for coagulase-positive Staphylococcus. Results of antibiogram showed that; 56.25% of the samples were resistant to Vancomycin, 50% to Penicillin, 31.25% to Tetracycline and Ampicillin, 18.75% to Erythromycin and Enrofloxacin, 12.5% to Oxacillin, 6.25% to Gentamicin and Clindamycin, whereas, only Cephalothin did not show resistance to any of the samples tested. Current study reported that antibiotic resistant strains (ARS) of coagulase-positive Staphylococcus sp. were present in the collected samples; and could have been originated from the food handlers, the utensils, the environment, or even from the animal itself. Accordingly, such results showed that it is important to stimulate the good hygiene and sanitary conditions of the food handlers, making them aware of their responsibility towards single health. Moreover, the indiscriminate use of antimicrobials may be responsible for the increase in the antibiotic resistant S. aureus.