A case report: Actinobaculum suis infection associated with formation of pyogranuloma, epididymitis and azoospermia in a boar.

BACKGROUND: Actinobaculum suis is a bacterium known to cause infections of the urogenital tract of sows. Infection can occur through close contact to boars, who frequently carry the pathogen in their preputial diverticulum but do not become clinically diseased themselves. In the current case, Actinobaculum suis was isolated from pyogranuloma of inflamed epididymis in a boar with poor fertility. CASE PRESENTATION: Increased return to oestrus rate, which worsened after the purchase of a new boar, was reported in an organic farm in Switzerland. During herd examination, azoospermia of the boar was diagnosed, and slaughter, followed by examination of its urogenital tract, was carried out. Pathologically, pyogranuloma formation and epididymitis were diagnosed. Bacteriology of the pyogranulomas showed growth of Actinobaculum suis and mixed flora. After the boar was replaced, the return to oestrus rate improved tremendously. CONCLUSION: A close relative of Actinobaculum suis, namely Actinotignum schaalii, has already been associated with epididymitis in humans. Considering the present case and the parallels in human medicine, Actinobaculum suis should be included in the list of differentials of boars with poor fertility.

Experimentally Induced Endometritis Impairs the Developmental Capacity of Bovine Oocytes†.

Uterine infection is associated with infertility in women and dairy cows, even after the resolution of infection. However, the mechanisms causing this persistent infertility are unclear. Here, we hypothesized that induced endometritis in non-lactating dairy cows would reduce the developmental competence of oocytes. Non-lactating Holstein cows received an intrauterine infusion of endometrial pathogenic bacteria (Escherichia coli and Trueperella pyogenes; n = 12) or vehicle control (n = 11) on day 2 of the estrous cycle. Bacterial infusion increased expression of endometrial inflammatory mediators, and a mucopurulent discharge in the vagina confirmed the establishment of endometritis. Oocytes were collected by transvaginal ultrasound-guided ovum pickup on days 2, 24, 45, and 66 following infusion and subjected to in vitro fertilization and embryo culture. Bacterial infusion resulted in fewer cleaved oocytes developing to morulae compared to vehicle-infused controls (30.7 versus 45.0%), with the greatest effect observed in oocytes collected on day 24. Development to morula was inversely correlated with endometrial expression of IL6 on day 6. The expression of genes associated with embryo quality did not differ significantly between morulae from bacteria-infused and control cows. Artificial insemination 130 days after intrauterine infusion resulted in normal, filamentous embryos that produced interferon tau 16 days after conception in both infusion groups. This model of experimentally induced uterine infection successfully resulted in endometritis and a reduction in the proportion of oocytes that developed to morulae following in vitro fertilization. In conclusion, endometritis reduced the capacity of oocytes to develop to morulae.

Clinical and Biological Features of Cutibacterium (Formerly Propionibacterium) avidum, an Underrecognized Microorganism.

The recent description of the genus Cutibacterium has altered the taxonomy of Propionibacterium species. These organisms still belong to the genera of the skin coryneform group, and the most-studied species remains Cutibacterium acnes. Cutibacterium avidum is also a known skin commensal. This underrecognized microorganism can, however, act as a pathogen after bacterial seeding and can be considered opportunistic, causing either superficial or deep/invasive infections. It can cause numerous infections, including but not limited to breast infections, skin abscesses, infective endocarditis, and device-related infections. The ecological niche of C. avidum is clearly different from that of other members of the genus: it is found in the axillary region or at wet sites rather than in dry, exposed areas, and the number of microorganisms increases during puberty. Historically, it has been used for its ability to modulate the immune response and for its antitumor properties. Conventional microbial culture methods and identification processes allow for its accurate identification and characterization. Thanks to the modern omics tools used for phylogenomic approaches, understanding C. avidum pathogenesis (including host-bacterium interactions and virulence factor characterization) is becoming easier, allowing for more thorough molecular characterization. These analyses have revealed that C. avidum causes diverse diseases mediated by multiple virulence factors. The recent genome approach has revealed specific genomic regions within this species that are involved in adherence and biofilm formation as well as fitness, survival, and defense functions. Numerous regions show the presence of phages and horizontal gene transfer. C. avidum remains highly sensitive to a broad spectrum of antibiotics, such as ß-lactams, fluoroquinolones, macrolides, and rifampin, although erythromycin and clindamycin resistance has been described. A long-term treatment regimen with a combination of antibiotics is required to successfully eliminate the remaining adherent bacteria, particularly in the case of deep infections after debridement surgery.

Arcanobacterium haemolyticum Utilizes Both Phospholipase D and Arcanolysin To Mediate Its Uptake into Nonphagocytic Cells.

Arcanobacterium haemolyticum is an emerging human pathogen that causes pharyngitis and wound infections. A few studies have suggested that A. haemolyticum is able to induce its uptake into nonphagocytic epithelial cells, but the bacterial factors associated with host cell invasion and the host cell processes involved have yet to be studied. We investigated how two A. haemolyticum virulence factors, arcanolysin (ALN) and phospholipase D (PLD), affect the ability of the bacteria to adhere to and subsequently invade Detroit 562 pharyngeal epithelial cells. The sphingomyelinase activity of phospholipase D was necessary to increase bacterial adherence, while the absence of a functional arcanolysin had no effect on A. haemolyticum adherence but did lead to a decrease in A. haemolyticum invasion into Detroit 562 cells. Because of the known roles of cholesterol-dependent cytolysins in disrupting calcium gradients and inducing F-actin-mediated bacterial internalization, we sought to determine whether ALN and PLD played a similar role in the ability of A. haemolyticum to invade nonphagocytic cells. Elimination of extracellular calcium and inhibition of the Arp2/3 complex or F-actin polymerization also caused a decrease in the ability of A. haemolyticum to invade Detroit 562 cells. Overall, our findings suggest that A. haemolyticum utilizes phospholipase D primarily for adherence and utilizes arcanolysin primarily for invasion into Detroit 562 cells in a process dependent on extracellular calcium and F-actin polymerization. Our work marks the first insight into how the individual activities of arcanolysin and phospholipase D affect A. haemolyticum host-pathogen interactions using the biologically relevant Detroit 562 cell line.

Rhodococcus equi pVAPN type causing pneumonia in a dog coinfected with canine morbillivirus (distemper virus) and Toxoplasma gondii.

Canine morbillivirus (previously, canine distemper virus, CDV) is a highly contagious infectious disease-causing agent that produces immunosuppressive infections and multiple clinical signs. Canine toxoplasmosis is an opportunistic disease characterized by enteric, pulmonary, and neuromuscular signs that might be confused with CDV-induced infections. Rhodococcus equi is a Gram-positive intracellular facultative bacterium that is also opportunistic in nature, and causes pyogranulomatous infections in humans and multiple host animals, although canine rhodococcosis is rare or unrecognized. The pathogenicity of R. equi is intimately related to the presence of plasmid-encoded virulence-associated proteins (Vap). Three host-adapted virulence plasmid types of R. equi have been recognized: the circular pVAPA and pVAPB are associated with equine and porcine strains, respectively, and the recently detected linear pVAPN virulence plasmid is related to bovine isolates. Nevertheless, data regarding the detection of host-adapted virulence plasmid types of R. equi isolated from companion animals are scarce. This report describes a case of an uncommon coinfection due to R. equi, T. gondii and CDV, which was diagnosed in a pet dog with respiratory distress. In this case, CDV most likely induced immunosuppression, which facilitated opportunistic infections by R. equi and T. gondii. The analysis of the virulence profile of R. equi revealed the novel pVAPN plasmid type, initially related to bovine strains. This is the second report of the bovine-associated pVAPN type in a pet dog, with an unusual coinfection with T. gondii and CDV. These findings represent a public health concern due to the close contact between pet animals and their owners, particularly because the pVAPN plasmid type was recently detected in people with HIV/AIDS from the same geographical region.

Ophthalmologic findings associated with Rhodococcus equi bronchopneumonia in foals.

OBJECTIVE: To describe ocular findings associated with Rhodococcus equi bronchopneumonia in foals, and to determine whether severity of the ocular lesions is related with outcome. ANIMALS STUDIED: Foals diagnosed with R equi infection at the VTH-UAB from January 2002 to December 2017. PROCEDURE: Rhodococcus equi infection was diagnosed by means of clinical signs, radiographic/ultrasonographic findings, and/or positive culture. In all the foals, a complete ophthalmic examination by a boarded ophthalmologist was performed and ocular signs were recorded and graded (0-4). RESULTS: Thirty-nine foals were included in the study, from which 12 showed signs of bilateral anterior uveitis (30.8%). Among these, three foals were classified as mildly uveitis-affected (MUA:7.7%) and nine as severely uveitis-affected (SUA:23.1%). Five SUA foals showed green aqueous flare (5/9;55.5%). Despite the systemic treatment, 9/39 sick foals died (23.1%), the fatality rate being different between groups: SUA (4/9;44.4%), MUA (0/3; 0%) and nonuveitis-affected foals (5/27;18.5%). Among SUA foals, only one with green aqueous flare died (1/5;20%). CONCLUSION: Bilateral anterior uveitis is highly prevalent in foals with R equi pneumonia (30.8%). The severity of anterior uveitis might be considered a nonsurvival prognostic factor and, until proven otherwise, green aqueous flare could be taken as a strongly suggestive ocular sign of the disease. Findings of this study remark the clinical relevance of performing a complete ophthalmic examination in sick foals, in order to help in the diagnosis and prognosis of uveal diseases, as well as to guaranteeing visual soundness.

Skin and soft tissue infection caused by Cutibacterium (formerly Propionibacterium) avidum: Report of eleven cases.

We describe the characteristics of 11 cases of skin and soft tissue infections due to Cutibacterium (formerly Propionibacterium) avidum. This microorganism should be considered a potential skin pathogen especially in patients with breast infections. The clinical outcome is usually good but serious infections such as necrotizing infections may occur.

Genomic characterisation, detection of genes encoding virulence factors and evaluation of antibiotic resistance of Trueperella pyogenes isolated from cattle with clinical metritis.

Trueperella pyogenes is one of the most important microorganisms causing metritis in post-partum cattle. Co-infection with other bacterial species such as Escherichia coli or Fusobacterium necrofurom increases the severity of the disease and the persistence of bacteria in utero. The aim of this study was to investigate the frequency of T. pyogenes strains, and their virulence and antimicrobial resistant profiles in metritis cases. The study was carried out on 200 samples obtained from metritis discharges of postpartum cattle on 18 farms around Tehran, Iran. Sixty-five T. pyogenes isolates (32.5%) were identified, of which 16 isolates were detected as pure cultures and the other 49 isolates from cultures most commonly mixed with E. coli or F. necrofurom. In terms of diversity in biochemical characteristic of T. pyogenes strains, 8 different biotypes were identified among the isolates. Single or multi antimicrobial resistance was observed in 48 isolates (73.9%), which was mostly against trimethoprim sulfamethoxazole, azithromycin, erythromycin and streptomycin. The tetracycline resistance gene tetW and macrolide resistance genes ermB and ermX were detected in 30, 18 and 25 isolates, respectively. In the screening of genes encoding virulence factors, fimA and plo genes were identified in all tested isolates. Genes encoding nanP, nanH, fimC, fimG, fimE and cbpA were detected in 50, 54, 45, 40, 50 and 37 of isolates, respectively. Thirteen different genotypes were observed in these T. pyogenes isolates. A significant association between clonal types and virulence factor genes, biochemical profile, CAMP test result, severity of the disease and sampling time was detected.

Rhodococcus equi Infections in Goats: Characterization of Virulence Plasmids.

Rhodococcus equi is an uncommon cause of systemic pyogranulomatous infections in goats with macroscopic similarities to caseous lymphadenitis caused by Corynebacterium pseudotuberculosis. Caprine cases have previously been reported to be caused by avirulent R. equi strains. Six cases of R. equi infection in goats yielding 8 R. equi isolates were identified from 2000 to 2017. Lesions varied from bronchopneumonia, vertebral and humeral osteomyelitis, and subcutaneous abscesses, to disseminated infection involving the lungs, lymph nodes, and multiple visceral organs. Isolates of R. equi from infected goats were analyzed by polymerase chain reaction for R. equi virulence-associated plasmid ( vap) genes. Seven of 8 isolates carried the VapN plasmid, originally characterized in bovine isolates, while 1 isolate lacked virulence plasmids and was classified as avirulent. The VapN plasmid has not been described in isolates cultured from goats.

INTERDIGITAL NECROBACILLOSIS ASSOCIATED WITH TRUEPERELLA PYOGENES IN GOITERED GAZELLES ( GAZELLA SUBGUTTUROSA).

This study presents the clinical findings, treatment results, and gross pathology of Trueperella pyogenes-associated interdigital necrobacillosis in captive goitered gazelles ( Gazella subgutturosa). Four male and two female gazelles presented with weight loss, front limb swelling, and persistent lameness despite antibiotic treatment. The animals were reluctant to bear weight on the affected limbs, and the diagnosis of interdigital necrobacillosis was made based on physical exam, bacteriologic evaluation, and radiographic imaging. In all cases, the interdigital skin and subcutaneous tissues were affected in both forelimbs. Exungulation (loss of the hoof) occurred in one female gazelle. Despite aggressive topical and systemic treatment, the two female gazelles died. Gross pathology detected abscesses in the heart, lung, and liver. T. pyogenes was isolated as the major pathogen. This is the first report of interdigital necrobacillosis caused by T. pyogenes in Gazella subgutturosa.

Comparative transcriptome analysis of Trueperella pyogenes reveals a novel antimicrobial strategy.

Trueperella pyogenes is a prevalent opportunistic bacterium that normally causes diverse suppurative lesions, endometritis and pneumonia in various economically important animals. Although the genomic information of this species has been announced, little is known about its functional profiles. In this study, by performing a comparative transcriptome analysis between the highly and moderately virulent T. pyogenes isolates, we found the expression of a LuxR-type DNA-binding response regulator, PloR, was significantly up-regulated in the highly virulent T. pyogenes. Protein crystal structure prediction and primary functional assessment suggested that, the quorum-sensing signal molecules of Gram-negative bacteria such as Pseudomonas aeruginosa and Escherichia coli could significantly inhibit the growth, biofilm production and hemolysis of T. pyogenes by binding to the upstream sensor histidine kinase, PloS. Therefore, the PloS/PlosR two-component regulatory system might dominate the virulence of T. pyogenes. Our findings provide a major advance in understanding the pathogenesis of T. pyogenes, and may shed new light on the development of novel therapeutic strategies to control T. pyogenes infection.

Clinical and microbiological features of Actinotignum bacteremia: a retrospective observational study of 57 cases.

The purpose of this study was to investigate the incidence, clinical presentation, and prognosis of Actinotignum bacteremia in southern Sweden. Actinotignum isolates in blood cultures were identified retrospectively between 1st January 2012 and 31st March 2016 through searches in the clinical microbiology laboratory database. The population covered by this laboratory is approximately 1.3 million. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used for species determination. Etests were used for minimum inhibitory concentration (MIC) determination. The patients' medical charts were reviewed. Fifty-eight episodes in fifty-seven patients with Actinotignum bacteremia were identified (A. schaalii = 53, A. sanguinis = 1, A. urinale = 2, and Actinotignum species = 3), which corresponds to an incidence of 11 cases per million inhabitants. Fifty-one percent of the isolates were in pure culture. The MICs were low for ß-lactam antibiotics, whereas high MICs were recorded for ciprofloxacin and trimethoprim. Patients had a median age of 82 years, 72% were male, and a majority had underlying urological conditions. Thirty-six of the patients were diagnosed with a focus from the urinary tract. Thirty-one patients developed severe sepsis and nine patients died during the hospital stay. Our study is the largest of Actinotignum bacteremia and demonstrates that it is a condition with a significant fatality that affects elderly persons with underlying conditions. ß-Lactams represent a rational treatment option.

Rhodococcus equi Infections in Dogs.

Five cases of Rhodococcus equi infection in dogs were identified from 2003 to 2014. Three of the dogs had severe, internal lesions attributable to R. equi that have not been previously described: endophthalmitis, endocarditis, and suppurative pleuropneumonia. Isolates from 4 of the dogs were analyzed by polymerase chain reaction for Rhodococcus virulence-associated plasmid (vap) genes. One isolate was vapA-positive, 2 lacked a virulence plasmid, and 1 carried the novel vapN-associated plasmid (pVAPN) recently characterized in bovine isolates. The pVAPN plasmid has not been described in isolates cultured from companion animals. Four of the dogs either were receiving immunosuppressive drugs or had endocrinopathies. R. equi has the potential to cause significant infections in dogs, and immunocompromised animals should be considered at risk for infection.

Postvaccination wounds associated predominantly with Arcanobacterium phocae in mink (Neovison vison) at three mink farms.

BACKGROUND: The emerging skin disease fur animal epidemic necrotic pyoderma (FENP) has been attributed to infection with Arcanobacterium phocae (ABP). The exact pathogenesis and risk factors of FENP have yet to be elucidated. ANIMALS: Three mink from each of three different mink farms (A-C) with postvaccination skin wounds at the vaccination site and six mink from an unaffected mink farm (D) that had used the same vaccine batch and vaccination site (hind leg). METHODS AND RESULTS: All mink from farms A-C had severe necrotizing to necropurulent dermatitis where they were vaccinated intramuscularly in the hind leg. ABP was the sole bacterium cultured from six of nine wounds. Using 16S-23S rDNA intergenic spacer region and BOX-PCR, the ABP isolates from these wounds were indistinguishable from isolates originating from several cases of FENP. CONCLUSIONS AND CLINICAL IMPORTANCE: This is the first report of FENP-like lesions at the site of vaccination, in the days following the procedure, associated with ABP. At farms with FENP vaccination, procedures should be considered carefully.

Clinicopathologic correlation: mixed-density lesion in the posterior mandible.

A middle-aged man presented for evaluation of a mixed-density lesion of the left posterior mandible. This clinicopathologic correlation presents the radiographic, clinical, and histopathologic findings; differential diagnosis; and treatment plan for this case. The lesion was deemed to be of bacteriologic origin, likely a polymicrobial infection containing actinomycetes. Clinical care and follow-up for the patient are discussed.

Infections by Renibacterium salmoninarum and Nanophyetus salmincola Chapin are associated with reduced growth of juvenile Chinook salmon, Oncorhynchus tshawytscha (Walbaum), in the Northeast Pacific Ocean.

We examined 1454 juvenile Chinook salmon, Oncorhynchus tshawytscha (Walbaum), captured in nearshore waters off the coasts of Washington and Oregon (USA) from 1999 to 2004 for infection by Renibacterium salmoninarum, Nanophyetus salmincola Chapin and skin metacercariae. The prevalence and intensities for each of these infections were established for both yearling and subyearling Chinook salmon. Two metrics of salmon growth, weight residuals and plasma levels of insulin-like growth factor-1, were determined for salmon infected with these pathogens/parasites, both individually and in combination, with uninfected fish used for comparison. Yearling Chinook salmon infected with R. salmoninarum had significantly reduced weight residuals. Chinook salmon infected with skin metacercariae alone did not have significantly reduced growth metrics. Dual infections were not associated with significantly more severe effects on the growth metrics than single infections; the number of triple infections was very low and precluded statistical comparison. Overall, these data suggest that infections by these organisms can be associated with reduced juvenile Chinook salmon growth. Because growth in the first year at sea has been linked to survival for some stocks of Chinook salmon, the infections may therefore play a role in regulating these populations in the Northeast Pacific Ocean.

Orbital necrotizing fasciitis and osteomyelitis caused by arcanobacterium haemolyticum: a case report.

The facial region is infrequently affected by necrotizing infections. Orbital necrotizing infections are even rarer, seen following trauma, local skin infection, and sinusitis. The authors report a unique case of orbital necrotizing fasciitis and osteomyelitis resulting from Arcanobacterium Haemolyticum ethmoid sinusitis. No prior occurrences of Arcanobacterial species orbital necrotizing fasciitis/osteomyelitis have been reported.A 16-year-old boy presented to the ER with a 3-day history of fever, chills, headache, and sinus pressure. CT scan revealed soft tissue swelling of the right orbit, forehead, and ethmoid sinusitis. Within 24 hours of admission, he suffered rapidly progressive swelling and erythema of the right orbit and forehead with diminished visual acuity, despite broad-spectrum antibiotics. Orbital exploration revealed frankly necrotic fascia and periosteum along the superior aspect. Lateral canthotomy, cantholysis, decompression of the optic nerve, and soft tissue debridement with bone biopsy was performed. Operative specimens isolated Arcanobacterium Haemolyticum. Pathologic examination revealed right orbital osteomyelitis.

Actinobaculum schaalii bacteremia: A report of two cases.

We report two cases of bacteremia with Actinobaculum schaalii, a rarely reported, anaerobic, Gram-positive bacterium. The first case was a patient with renal cancer who developed pyelonephritis after cryoablation, and the second was a patient who developed sepsis after a urogenital procedure. Bacteremia resolved after administration of empiric antibiotic therapy.

Catheter-related bloodstream infection by Tsukamurella inchonensis in an immunocompromised patient.

We report a case of catheter-related bloodstream infection by Tsukamurella inchonensis, identified using 16S rRNA gene sequencing, in a patient with myelofibrosis who underwent a bone marrow transplant. Tsukamurella species infections are rare. To our knowledge, this is the first case of T. inchonensis bloodstream infection in an immunocompromised patient.

Differential endometrial cell sensitivity to a cholesterol-dependent cytolysin links Trueperella pyogenes to uterine disease in cattle.

Purulent disease of the uterus develops in 40% of dairy cows after parturition, when the epithelium of the endometrium is disrupted to expose the underlying stroma to bacteria. The severity of endometrial pathology is associated with isolation of Trueperella pyogenes. In the present study, T. pyogenes alone caused uterine disease when infused into the uterus of cattle where the endometrial epithelium was disrupted. The bacterium secretes a cholesterol-dependent cytolysin, pyolysin (PLO), and the plo gene was identical and the plo gene promoter was highly similar amongst 12 clinical isolates of T. pyogenes. Bacteria-free filtrates of the T. pyogenes cultures caused hemolysis and endometrial cytolysis, and PLO was the main cytolytic agent, because addition of anti-PLO antibody prevented cytolysis. Similarly, a plo-deletion T. pyogenes mutant did not cause hemolysis or endometrial cytolysis. Endometrial stromal cells were notably more sensitive to PLO-mediated cytolysis than epithelial or immune cells. Stromal cells also contained more cholesterol than epithelial cells, and reducing stromal cell cholesterol content using cyclodextrins protected against PLO. Although T. pyogenes or plo-deletion T. pyogenes stimulated accumulation of inflammatory mediators, such as IL-1beta, IL-6, and IL-8, from endometrium, PLO did not stimulate inflammatory responses by endometrial or hematopoietic cells, or in vitro organ cultures of endometrium. The marked sensitivity of stromal cells to PLO-mediated cytolysis provides an explanation for how T. pyogenes acts as an opportunistic pathogen to cause pathology of the endometrium once the protective epithelium is lost after parturition.