Virulence Mechanisms of Staphylococcal Animal Pathogens.

Staphylococci are major causes of infections in mammals. Mammals are colonized by diverse staphylococcal species, often with moderate to strong host specificity, and colonization is a common source of infection. Staphylococcal infections of animals not only are of major importance for animal well-being but have considerable economic consequences, such as in the case of staphylococcal mastitis, which costs billions of dollars annually. Furthermore, pet animals can be temporary carriers of strains infectious to humans. Moreover, antimicrobial resistance is a great concern in livestock infections, as there is considerable antibiotic overuse, and resistant strains can be transferred to humans. With the number of working antibiotics continuously becoming smaller due to the concomitant spread of resistant strains, alternative approaches, such as anti-virulence, are increasingly being investigated to treat staphylococcal infections. For this, understanding the virulence mechanisms of animal staphylococcal pathogens is crucial. While many virulence factors have similar functions in humans as animals, there are increasingly frequent reports of host-specific virulence factors and mechanisms. Furthermore, we are only beginning to understand virulence mechanisms in animal-specific staphylococcal pathogens. This review gives an overview of animal infections caused by staphylococci and our knowledge about the virulence mechanisms involved.

Antibiotic resistance in porcine pathogenic bacteria and relation to antibiotic usage.

BACKGROUND: Optimal treatment and prudent use of antimicrobials for pigs is imperative to secure animal health and prevent development of critical resistance. An important step in this one-health context is to monitor resistance patterns of important animal pathogens. The aim of this study was to investigate the antimicrobial resistance patterns of five major pathogens in Danish pigs during a period from 2004 to 2017 and elucidate any developments or associations between resistance and usage of antibiotics. RESULTS: The minimum inhibitory concentration (MIC) for Escherichia coli, Actinobacillus pleuropneumoniae, Streptococcus suis, Bordetella bronchiseptica, and Staphylococcus hyicus was determined to representatives of antibiotic classes relevant for treatment or surveillance. Escherichia coli isolates were mostly sensitive to fluoroquinolones and colistin, whereas high levels of resistance were observed to ampicillin, spectinomycin, streptomycin, sulfonamides and tetracycline. While resistance levels to most compounds remained relatively stable during the period, resistance to florfenicol increased from 2.1% in 2004 to 18.1% in 2017, likely in response to a concurrent increase in usage. A temporal association between resistance and usage was also observed for neomycin. E. coli serovars O138 and O149 were generally more resistant than O139. For A. pleuropneumoniae, the resistance pattern was homogenous and predictable throughout the study period, displaying high MIC values only to erythromycin whereas almost all isolates were susceptible to all other compounds. Most S. suis isolates were sensitive to penicillin whereas high resistance levels to erythromycin and tetracycline were recorded, and resistance to erythromycin and trimethoprim increasing over time. For S. hyicus, sensitivity to the majority of the antimicrobials tested was observed. However, penicillin resistance was recorded in 69.4-88.9% of the isolates. All B. bronchiseptica isolates were resistant to ampicillin, whereas all but two isolates were sensitive to florfenicol. The data obtained have served as background for a recent formulation of evidence-based treatment guidelines for pigs. CONCLUSIONS: Antibiotic resistance varied for some pathogens over time and in response to usage. Resistance to critically important compounds was low. The results emphasize the need for continuous surveillance of resistance patterns also in pig pathogenic bacteria.

In vitro antibacterial activity of plant essential oils against Staphylococcus hyicus and Staphylococcus aureus, the causative agents of exudative epidermitis in pigs.

Greasy pig disease or exudative epidermitis, a generalized or localized skin disease affecting piglets, is mainly caused by Staphylococcus hyicus, although other staphylococcal species such as Staphylococcus aureus may also induce disease. Piglets with skin lesions can be treated systemically with antibiotics. However, antimicrobial resistance to ß-lactam antibiotics are now frequently observed in S. hyicus and S. aureus isolates. In this study, the antibacterial activity of plant essential oils as well as their ability to potentiate the effect of several antimicrobial compounds against S. hyicus and S. aureus were investigated with a view to a potential use as skin disinfectants. Among ten essential oils tested, those from cinnamon, thyme, and winter savory were the most active with minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values ranging from 0.078 to 0.313% (v/v). Using a fluorescent probe with DNA affinity, it was found that thyme and winter savory oils act, at least in part, by disturbing the bacterial membrane integrity. At concentrations below the MIC, thyme and winter savory oils reduced biofilm formation by S. hyicus. Moreover, a treatment of pre-formed biofilms of S. hyicus with cinnamon or thyme oils significantly decreases its viability. Synergistic interactions between essential oils, more particularly from thyme and winter savory, and penicillin G, chlorhexidine or nisin, were observed. This study supports the therapeutic potential of essential oils as topical therapeutic agents against exudative epidermitis.

Vertebral Osteomyelitis and Septic Arthritis Associated With Staphylococcus hyicus in a Juvenile Peregrine Falcon ( Falco peregrinus ).

A 6-week-old, parent-reared peregrine falcon ( Falco peregrinus ) was presented with spastic hypertonus of its hind limbs of unknown origin and duration. Radiologic examination revealed smooth periosteal reactions ventrally at thoracic vertebrae 5 to 7. Contrast-enhanced computed tomography identified the swelling as inflammation; antibiotic, antimycotic, anti-inflammatory, and analgesic treatments were initiated, and vitamins and minerals were supplemented. Because the bird's condition did not improve after 10 days, it was euthanatized and submitted for postmortem examination. On histopathologic examination, chronic, active osteomyelitis was diagnosed in thoracic vertebrae 5 to 7, and chronic, active arthritis was present in both the right shoulder and left elbow joints. Staphylococcus hyicus was isolated from these 3 locations, as well as from lungs and liver, indicating a chronic septic staphylococcosis. Although infections with Staphylococcus species are occasional causes of vertebral osteomyelitis in juvenile poultry with active growth plates, it is only sporadically reported in raptors and companion birds. This case report is the first description of the clinical features and diagnostic and pathologic findings in a juvenile peregrine falcon with hematogenous osteomyelitis and arthritis associated with septicemia caused by S hyicus.

Insights into the Virulence and Antimicrobial Resistance of Staphylococcus hyicus Isolates from Spanish Swine Farms.

Staphylococcus hyicus is a significant pathogen in swine, primarily causing exudative epidermitis. Addressing S. hyicus infections requires both the characterization of virulence and antimicrobial resistance (AMR) in farm-recovered isolates. This study aimed to characterize the virulence, AMR, and biofilm formation of S. hyicus isolates from Spanish swine farms. A total of 49 isolates were analyzed, originating from animals with cutaneous, reproductive, and systemic clinical signs. Half of the isolates (49.0%) were positive for at least one virulence factor (VF) gene, with SHETA being the most frequent (28.6%). A high frequency of multidrug resistant (MDR) isolates was observed (83.7%), with significant resistance to commonly used antimicrobials, including lincosamides (83.7%), pleuromutilins (81.6%), penicillins (75.5%), and tetracyclines (73.5%). All isolates exhibited robust in vitro biofilm formation capacity (DC = 15.6 ± 7.0). Significant associations were found between VFs, biofilm formation, and AMR patterns, highlighting the link between the resistance to lincosamides and pleuromutilins (p < 0.001; Φ = 0.57) and macrolides (p < 0.001; Φ = 0.48), and the association of AMR with the ExhC and ExhD VF genes. These findings underscore the need for targeted diagnostics to improve management and therapeutic strategies to mitigate the impact of S. hyicus on swine production.

Draft genome sequences of four Staphylococcus hyicus strains, SC302, SC304, SC306, and SC310, isolated from swine from Eastern Canada.

The bacterium Staphylococcus hyicus causes porcine exudative epidermitis in piglets, which represents both health and welfare concerns. Few genome sequences of this pathogen are published. We provide four additional ones to help future genomic analysis of S. hyicus. These are genomes of strains isolated from Canadian swine.

Antimicrobial Resistance Profile of Staphylococcus hyicus Strains Isolated from Brazilian Swine Herds.

Staphylococcus hyicus is the causative agent of porcine exudative epidermitis. This disorder affects animals in all producing countries and presents a widespread occurrence in Brazil. This study evaluated strains from a historical collection in order to detect the presence of exfoliative-toxin-encoding genes (SHETB, ExhA, ExhB, ExhC, ExhD), characterize the strains using PFGE, and determine their respective antimicrobial resistance profiles. The results obtained from the evaluation of 77 strains from 1982 to 1987 and 103 strains from 2012 reveal a significant change in resistance profiles between the two periods, especially regarding the antimicrobial classes of fluoroquinolones, amphenicols, lincosamides, and pleuromutilins. The levels of multidrug resistance observed in 2012 were significantly higher than those detected in the 1980s. It was not possible to correlate the resistance profiles and presence of genes encoding toxins with the groups obtained via PFGE. Only 10.5% of the strains were negative for exfoliative toxins, and different combinations of toxins genes were identified. The changes observed in the resistance pattern of this bacterial species over the 30-year period analyzed indicate that S. hyicus could be a useful indicator in resistance monitoring programs in swine production. In a country with animal protein production such as Brazil, the results of this study reinforce the need to establish consistent monitoring programs of antimicrobial resistance in animals, as already implemented in various countries of the world.

Role of Staphylococcus agnetis and Staphylococcus hyicus in the Pathogenesis of Buffalo Fly Skin Lesions in Cattle.

Buffalo flies (Haematobia irritans exigua) are hematophagous ectoparasites of cattle causing production and welfare impacts in northern Australian herds. Skin lesions associated with buffalo fly infestation and Stephanofilaria nematode infection are manifested as focal dermatitis or ulcerated areas, most commonly on the medial canthus of the eye, along the lateral and ventral neck, and on the abdomen of cattle. For closely related horn flies (Haematobia irritans irritans), Staphylococcus aureus has been suggested as a contributing factor in the development of lesions. To investigate the potential role of bacterial infection in the pathogenesis of buffalo fly lesions, swabs were taken from lesions and normal skin, and bacteria were also isolated from surface washings of buffalo flies and surface-sterilized homogenized flies. Bacterial identification was conducted by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) and strain typing by repetitive sequence-based PCR (rep-PCR) and DNA sequencing to determine species similarity and virulence factors. Of 50 bacterial isolates collected from lesions, 38 were identified as Staphylococcus agnetis and 12 as Staphylococcus hyicus, whereas four isolates from normal skin were S. hyicus and one was Mammaliicoccus sciuri. Of the Staphylococcus isolates isolated from buffalo flies, five were identified as S. agnetis and three as S. hyicus. Fifty percent of the buffalo fly isolates had rep-PCR genotypic patterns identical to those of the lesion isolates. Genome sequencing of 16 S. agnetis and four S. hyicus isolates revealed closely similar virulence factor profiles, with all isolates possessing exfoliative toxin A and C genes. The findings from this study suggest the involvement of S. agnetis and S. hyicus in buffalo fly lesion pathogenesis. This should be taken into account in the development of effective treatment and control strategies for lesions. IMPORTANCE Skin lesions in cattle associated with feeding by Haematobia fly species are a significant welfare issue in Australia, North and South America, and Europe. The development of these lesions has been attributed to a number of causal factors, but the exact etiology and pathogenesis were unclear. This study characterized Staphylococcus agnetis and Staphylococcus hyicus strains from cattle skin lesions and in vector flies and demonstrated their role in the pathogenesis of these lesions. These findings will aid the development of targeted and more effective treatment and control strategies for lesions associated with fly infestation in cattle.

First Molecular Characterization of Siphoviridae-Like Bacteriophages Infecting Staphylococcus hyicus in a Case of Exudative Epidermitis.

Exudative epidermitis (EE), also known as greasy pig disease, is one of the most frequent skin diseases affecting piglets. Zoonotic infections in human occur. EE is primarily caused by virulent strains of Staphylococcus (S.) hyicus. Generally, antibiotic treatment of this pathogen is prone to decreasing success, due to the incremental development of multiple resistances of bacteria against antibiotics. Once approved, bacteriophages might offer interesting alternatives for environmental sanitation or individualized treatment, subject to the absence of virulence and antimicrobial resistance genes. However, genetic characterization of bacteriophages for S. hyicus has, so far, been missing. Therefore, we investigated a piglet raising farm with a stock problem due to EE. We isolated eleven phages from the environment and wash water of piglets diagnosed with the causative agent of EE, i.e., S. hyicus. The phages were morphologically characterized by electron microscopy, where they appeared Siphoviridae-like. The genomes of two phages were sequenced on a MiSeq instrument (Illumina), resulting in the identification of a new virulent phage, PITT-1 (PMBT8), and a temperate phage, PITT-5 (PMBT9). Sequencing of three host bacteria (S. hyicus) from one single farm revealed the presence of two different strains with genes coding for two different exfoliative toxin genes, i.e., exhA (2 strains) and exhC (1 strain). The exhC-positive S. hyicus strain was only weakly lysed by most lytic phages. The occurrence of different virulent S. hyicus strains in the same outbreak limits the prospects for successful phage treatment and argues for the simultaneous use of multiple and different phages attacking the same host.

Exudative Epidermitis in Combination with Staphylococcal Pyoderma in Suckling Piglets.

A case of generalized exudative epidermitis (EE) is described, which occurred in a very small piglet producing farm in Austria. The antimicrobial treatment prescribed by the herd veterinarian did not improve the clinical problem. Therefore, the University Clinic for Swine intervened in the case. Lab investigations were initiated in which Staphylococcus hyicus (SH) and Staphylococcus aureus (SA), both methicillin-resistant and susceptible strains, could be isolated from the skin of affected piglets. Poor hygiene and management practices were identified as predisposing factors on site. Adaptation of antimicrobial treatment according to results of the in vitro susceptibility testing and the implementation of proper hygiene measures resolved the clinical problem. Here, we describe a fatal coinfection of SH and SA in suckling piglets.

Comparison of Host Cytokine Response in Piglets Infected With Toxigenic and Non-toxigenic Staphylococcus hyicus.

Staphylococcus hyicus is the most common causative agent of exudative epidermitis (EE) in piglets. Staphylococcus hyicus can be grouped into toxigenic and non-toxigenic strains based on its ability to cause EE in pigs. However, the inflammatory response of piglets infected with toxigenic and non-toxigenic S. hyicus has not been elucidated. In this study, we evaluated the serum cytokine profile in piglets inoculated with toxigenic and non-toxigenic S. hyicus strains and recorded the clinical signs in piglets. Fifteen piglets were divided into three groups (n = 5) and inoculated with a toxigenic strain (ZC-4), a non-toxigenic strain (CF-1), and PBS (control), respectively. The changes in serum levels of cytokines (interleukin [IL]-1ß, IL-4, IL-6, IL-8, IL-10, IL-12, granulocyte-macrophage colony-stimulating factor, interferon-γ, transforming growth factor-ß1, and tumor necrosis factor-α) were evaluated using a cytokine array at 6, 24, 48, and 72 h post inoculation. The results showed that piglets infected with the toxigenic strain exhibited more severe clinical signs and higher mortality than those infected with the non-toxigenic strain. The serum levels of pro-inflammatory cytokine IL-1ß were significantly increased in toxigenic-and non-toxigenic-strain-infected piglets compared to those in the control group (p < 0.05), while the anti-inflammatory cytokine IL-10 was significantly up-regulated only in toxigenic group than in control group (p < 0.05). These results indicated that piglets infected with toxigenic and non-toxigenic S. hyicus showed differential infection status and inflammatory responses. Both toxigenic- and non-toxigenic- S. hyicus infection could induce a pro-inflammatory reaction in piglets. In addition, the toxigenic strain induced a strong anti-inflammatory response in piglets as indicated by the increased serum level of IL-10, which may be associated with the severe clinical signs and increased mortality and may be the key cytokine response responsible for pathogenic mechanisms of S. hyicus.

Autogenous vaccination reduces antimicrobial usage and mortality rates in a herd facing severe exudative epidermitis outbreaks in weaned pigs.

This study was conducted in a commercial 1000-sow herd facing recurrent exudative epidermitis (EE) outbreaks during the nursery period and assessed the efficacy of autogenous vaccination in controlling such outbreaks. The vaccine was produced using three Staphylococcus hyicus isolates recovered from affected pigs shortly before the onset of the study. All of those isolates were positive for the exhB gene, which encodes the exfoliative toxin type B (ExhB). From four consecutive farrowing batches of sows, two batches were vaccinated (V) against S hyicus at five and two weeks before farrowing, and two sow batches remained non-vaccinated (NV). Vaccination efficacy was primarily determined by the levels of metaphylactic antimicrobial usage, and the morbidity and mortality data for the pigs of the V and NV sows. The total amount of antimicrobials used metaphylactically against EE in pigs among the V and NV farrowing batches was 39,600 and 88,550 mg, respectively. The used daily dose pig to animal daily dose pig ratio for the V and NV batches were 1.31 and 1.79, respectively (a ratio of 0.8 to 1.2 is indicative of correct dosing). The morbidity and mortality rates were V=6.50 and NV=14.36 (P=0.008), and V=2.59 and NV=5.02 (P=0.000), respectively. To conclude, autogenous vaccination of the sows with a vaccine based on exhB-positive S hyicus isolates reduced metaphylactic treatment with antimicrobials as well as the morbidity and mortality rates in weaned pigs compared with pigs from NV sow batches.

Evaluation of a novel thermo-alkaline Staphylococcus aureus lipase for application in detergent formulations.

An extracellular lipase of a newly isolated S. aureus strain ALA1 (SAL4) was purified from the optimized culture medium. The SAL4 specific activity determined at 60 °C and pH 12 by using olive oil emulsion or TC4, reached 7215 U/mg and 2484 U/mg, respectively. The 38 NH2-terminal amino acid sequence of the purified enzyme starting with two extra amino acid residues (LK) was similar to known staphylococcal lipase sequences. This novel lipase maintained almost 100% and 75% of its full activity in a pH range of 4.0-12 after a 24 h incubation or after 0.5 h treatment at 70 °C, respectively. Interestingly, SAL4 displayed appreciable stability toward oxidizing agents, anionic and non-ionic surfactants in addition to its compatibility with several commercial detergents. Overall, these interesting characteristics make this new lipase promising for its application in detergent industry.

Genetic and biochemical characterization of hyicin 3682, the first bacteriocin reported for Staphylococcus hyicus.

Hyicin 3682, the first bacteriocin reported for Staphylococcus hyicus, is a BsaCOL variant produced by S. hyicus 3682, a strain isolated from bovine milk. Hyicin 3682 is found in the culture supernatant, is bactericidal and its producing strain exhibits a much broader spectrum of antimicrobial activity than the producing strain of BsaCOL against several Gram-positive bacteria, which include foodborne pathogens, food-spoilage microorganisms and bacterial species of medical and veterinary importance. Sequencing of the genome of S. hyicus 3682 provided the nucleotide sequence of the entire gene cluster involved in hyicin 3682 production, which seems to be located on pRJ109, the single plasmid carried by this strain. This gene cluster is expressed and consists of 8525bp and of eight genes (hyiA, hyiB, hyiC, hyiD, hyiP, hyiF, hyiE and hyiG) encoded on the same DNA strand. The mature lantibiotic exhibits 91% identity to BsaCOL and its molecular mass was found to be ∼26Da higher due to two amino acid substitutions. S. hyicus 3682 proved to be only partially immune to its cognate bacteriocin up to 1024 AU/ml. Therefore, hyicin 3682, the first Bsa variant reported in coagulase-negative staphylococci, does exhibit antimicrobial and siblicidal activities.

Species level identification of coagulase negative Staphylococcus spp. from buffalo using matrix-assisted laser desorption ionization-time of flight mass spectrometry and cydB real-time quantitative PCR.

Incorrect identification of Staphylococcus spp. can have serious clinical and zoonotic repercussions. Accordingly, the aim of this study was to determine if matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and/or cydB real- time quantitative PCR (qPCR) could be used to accurately identify coagulase negative Staphylococcus spp. (CoNS) obtained from buffalo milk and milking environment samples. Seventy-five of 84 CoNS isolates could be identified to the species level (score value >1.99) using MALDI-TOF MS. However, as determined by cytochrome d ubiquinol oxidase subunit II (cydB) qPCR and by 16S RNA and cydB gene sequencing, 10S. agnetis strains were wrongly identified as S. hyicus by MALDI-TOF MS. In addition, 9 isolates identified by MALDI-TOF only to the genus level (score values between 1.70 and 1.99) could be identified to species by cydB qPCR. Our findings suggest that MALDI-TOF MS is a reliable method for rapid identification of S. chromogenes and S. epidermidis (species of interest both in human and veterinary medicine) and may be able to correctly identify other Staphylococcus spp. However, at present not all Staphylococcus spp. found in buffalo milk can be accurately identified by MALDI-TOF MS and for these organisms, the cydB qPCR developed in the current study may provide a reliable alternative method for rapid identification of CoNS species.

A fatal suppurative pneumonia in piglets caused by a pathogenic coagulase-positive strain of Staphylococcus hyicus.

Staphylococcus hyicus is one of the opportunistic pathogens that cause infections to animals. Early studies have demonstrated that S. hyicus is the causative agents of exudative epidermitis in pigs, arthritis in horses and chicken, mastitis in cow, and bacteremia, sepsis and multiple organ failure in humans. Here, we report the isolation and identification of a representative S. hyicus isolate, named JLHN15, from a pig farm with a disease characterized by bacteremia, suppurative pneumonia and fibrinous pericarditis. Our results indicate that JLHN15 is a pathogenic coagulase-positive Staphylococcus. To the best knowledge, this is the first report of S. hyicus causing an infection characterized by suppurative pneumonia and sepsis.

Spondylodiscitis and bacteremia due to Staphylococcus hyicus in an immunocompetent man.

INTRODUCTION: Staphylococcus hyicus is a coagulase-variable Staphylococcus spp. well-known by veterinarians since it is the major agent of a severe cutaneous infection in piglets called exudative epidermitis. In other species the symptoms of infection are quite different. Human cases are uncommon but seem to occur more frequently after repeated contacts with farm animals. CASE REPORT: We report the case of a 58-year-old man suffering from debilitating subacute lumbar pain, in whom diagnosis of infectious spondylodiscitis was based on spine MRI and positive microbiological results. A strain of S. hyicus was surprisingly isolated from blood cultures and bone biopsy. Identification was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS, Bruker, USA), and the patient was successfully cured with a six-week course of anti-staphylococcal antibiotic regimen. CONCLUSION: The prevalence of S. hyicus in human clinical samples is very low, but may be underestimated. This pathogen may enter the bloodstream through a skin injury, and then induce various pyogenic manifestations in people working with farm animals. S. hyicus exfoliative toxins, responsible for dermatological lesions in piglets, seem unable to damage the human epidermis, explaining the absence of cutaneous blisters in the previously reported cases. Precise data about its pathogenicity in humans and the adequate therapy are lacking.

Studies on the Virulence of Staphylococcus hyicus.

Abstract- Culture supernatants from six Staphylococcus hyicus isolates were concentrated by ultrafiltration and were injected intradermally into the abdominal skin of 2-week-old piglets. Two distinct types of reaction were observed; (1) a focal erythema and (2) an exfoliative reaction with crusting. The severity of these reactions and the number of animals affected differed between isolates. The exfoliative reaction observed in these skin tests may be a good indicator of virulence. Résumé- Les surnageants de six souches de Staphylococcus hyicus ont été concentrés par ultrafiltration et furent injectés par voie intradermique dans la peau de l'abdomen de porcelets ägés de deux semaines. Deux types distincts de réactions furent observés: (1) un éryhème focal et (2) une réaction d'exfoliation avec apparition de croûtes. L'intensité de ces réactions et le nombre d'animaux atteints différaient selon les souches. La réaction d'exfoliation observée lors de ces tests pourrait être un bon indicateur de virulence. Zusammenfassung- Überstände der Kultur von sechs Staphylococcus hyicus-Isolaten wurden durch Ultra-zentrifugieren konzentriert und bei 2 Wochen alten Ferkeln intradermal in die Abdominalhaut injiziert. Es konnten zwei deutlich unterscheidbare Reaktionen beobachtet werden: (1) ein fokales Erythem und (2) eine exfoliative Reaktion mit Krustenbildung. Die Schwere dieser Reaktionen und die Zahl der betroffenen Tiere war je nach Isolat unterscheidlich. Die exfoliative Reaktion bei diesen Hauttests könnte ein guter Indikator für die Virulenz sein. Resumen Los sobrenadantes de 6 cultivos diferentes de Staphylococcus hyicus se concentraron mediante ultrafiltración y se inyectaron via intradérmica en la piel abdominal de lechones de dos semanas de edad. Se observaron dos tipos de reacción: (1) un eritem focal y (2) una reacción exfoliativa y costrosa. La gravedad de las reacciones y el nümero de animales afectados variaba en functión del cultivo utilizado. La reacción exfoliativa que se observó en estos tests intradérmicos puede ser un buen indicador de virulencia.

Pathogenesis and management of wound infections in domestic animals.

Abstract The pathogenesis of wound infections is largely dependent on adherence mechanisms and toxins. Studies of Staphylococcus intermedins indicate that pyoderma isolates can bind to extracellular matrix proteins exposed in wounds but interpretation of adherence studies is complicated as some organisms possess multiple mechanisms. Studies of blocking and promotion of adherence by antibiotics also show variability. Epidermolytic toxins are recognized in S. aureus and S. hyicus but not in S. intermedins, although a synergohymenotropic toxin has been described and canine syndromes occur where epidermal splitting and S. intermedins infection co-exist. Staphylococcal enterotoxins and toxic shock toxin-1 are recognized as superantigens which cause cytokine release non-specifically, promoting inflammation in wounds. Treatment of infected skin depends largely on antibiotics but drug resistance will limit this; a move towards vaccines and re-examination of the value of antisepsis is occurring. Use of dressings which reduce microbial growth must also be a factor in wound management. Resumen La patogenesis de las infecciones de heridas depende en gran medida de los mecanismos de adherencia y de las toxinas. Algunos estudios en Staphylococcus intermedius indican que los aislamientos a partir de áreas de pioderma pueden adherirse a proteinas de la matriz extracelular expuesta en las heridas aunque la interpretación de estudios de adherencia es complicado ya que algunos organismos poseen múltiples mecanismos. Los estudios con antibióticos sobre su capacidad de bloqueo y promoción de la adherencia también muestran variabilidad. Se reconocen toxinas epidermolíticas en S. aureus y S. hyicus pero no en S. intermedius, aunque se ha descrito una toxina sinergohimenotrópica y se producen sindromes caninos en áreas de coexistencia de rotura epidérmica y S. intermedius. Las enterotoxinas estafilocócicas y la Toxina-1 de Shock Tóxico son reconocidas como superantígenos que causan liberación inespecífica de citoquinas, promoviendo la inflamación a nivel de las heridas. El tratamiento de la piel infectada depende en gran medida de los antibióticos, aunque esto se encuentra limitado por las resistencias; se está tendiendo a las vacunaciones y a una re-evaluación del valor de la antisepsia. El uso de vendas que reduzcan el crecimiento bacteriano deberia también ser un factor en el manejo de heridas. [Noble, W.C., Lloyd, D.H. Pathogenesis and management of wound infections in domestic animals (Patogenesis y manejo de heridas infectadas en animales domesticos). Veterinary Dermatology 1997; 8: 243-248] Zusammenfassung Die Pathogenese von Wundinfektionen hängt hauptsächlich von Haftungsmechanismen und Toxinen ab. Studien von Staphylokokkus intermedius weisen nach, dass Isolate von Pyodermien sich an in Wunden exponierte extrazelluläre Matrixproteine binden; die Interpretation dieser Haftungsstudien wird durch multiple Mechanismen einiger Organismen kompliziert. Studien, diese Haftung durch Antibiotika zu blockieren oder zu fördern, zeigen variable Ergebnisse. Epidermolytische Toxine sind für S. aureus und S. hyicus, aber nicht für S. intermedius beschrieben, obwohl von einem synergohymenotropischen Toxin berichtet wird und beim Hund Syndrome auftreten, in denen epidermale Spaltung und S. intermedius Infektion koexistieren. Enterotoxine und Toxischer Schock Toxin 1 von Staphylokokkus werden als Superantigene anerkannt, die nicht spezifische Zytokinfreisetzung verursachen und so die Entzündung in Wunden fördern. Die Behandlung infizierter Haut erfolgt weitgehend durch Antibiotika, aber Resistenzbildung wird deren Verwendung einschränken; im Moment geht die Tendenz mehr in Richtung Impfungen und die Neubewertung von Antisepsis. Die Verwendung von Verbandsmaterialien, die das Wachstum von Mikroorganismen einschränken, muss in der Wundversorgung berücksichtigt werden. [Noble, W.C., Lloyd, D.H. Pathogenesis and management of wound infections in domestic animals (Pathogenese und Versorgung von Wundinfektionen bei Haustieren). Veterinary Dermatology 1997; 8: 243-248] Résumé La pathogénie des plaies infectées dépend largement de mécanismes d'adhérence et de toxines. L'étude de Staphylococcus intermedius montre que des germes de pyodermite peuvent adhérer aux protéines des matrices extracellulaires mises à nu par des blessures mais l'interprétation des études d'adhérence est compliquée par le fait que certains germes possèdent de multiples mécanismes. Des études d'inhibition ou d'activation d'adhérence par des antibiotiques démontrent également une variabilité. On connait l'existence de toxines épidermolytiques chez S. aureus et S. hyicus mais pas chez S. intermedius, bien qu'une toxine synergohymenotropique ait été décrite, et que des syndrômes où clivage épidermique et infection àStaphylococcus intermedius coexistent aient été décrit chez le chien. II est admis que des entérotoxines staphylococciques et la toxine 1 du choc toxique agissent comme des superantigènes qui provoquent une libération non spécifique de cytokines, provoquant l'inflammation des plaies. Le traitement des plaies infectées dépend largement des antibiotiques mais est limité par le phénomène d'antibiorésistance; actuellement, une tendance à reconsidérer la valeur des vaccins et de l'antisepsie se dessine. L'utilisation de pansements qui réduisent la prolifération bactérienne peut également être un facteur du traitement des plaies. [Noble, W.C., Lloyd, D.H. Pathogenesis and management of wound infections in domestic animals (Pathogénie et traitement des plaies infectées chez les animaux domestiques). Veterinary Dermatology 1997; 8: 243-248].

Interaction of Staphylococcus hyicus and an inhibitor producing strain of Staphylococcus chromogenes on the skin of gnotobiotic piglets.

Abstract- The effects of an inhibitor-producing strain of Staphylococcus chromogenes on the colonisation and disease produced by virulent and avirulent strains of Staphylococcus hyicus were examined. In the presence of S. chromogenes the colonisation of the virulent strain was reduced one thousand fold and the onset of lesions was delayed by 7 days. The ability of the avirulent strain of S. hyicus to colonise skin was greatly reduced and populations became almost undetectable within 6 days of inoculation. Résumeé- Les effets d'une souche de Staphylococcus chromogenes, productrice d'un facteur d'inhibition, ont été examinés sur la colonisation et la maladie produites par des souches non virulentes et virulentes de Staphylococcus hyicus. En présence de S. chromogenes, la colonisation de la souche virulente a été réduite de 1000 fois, et l'apparition des lésions a été retardée de 7 jours. La faculté pour la souche non virulente de S. hyicus de coloniser la peau a été considérablement réduite et les populations sont devenues à peu près introuvables 6 jours après l'inoculation. Zusammenfassung- Die Wirkungen Inhibitor-produzierenden Art von Staphylococcus chromogenes auf die Kolonisierung und Erkrankung der Haut durch virulente und avirulente Arten von Staphylococcus hyicus wurden untersucht. In Gegenwart von S. chromogenes wurde die Kolonisierung der virulenten Art um den Faktor 1000 verringert und des Auftreten der Hautveränderungen um 7 Tage verzögert. Die Fähigkeit zur Kolonisierung der Haut durch die avirulente 5. hyicus-Art wurde sehr stark verringert, ihre Population konnte innerhalb von 6 Tagen nach Inokulation nicht mehr nachgewiesen werden. Resumen Se estudian los efectos de una cepa de Staphylococcus chromogenes productora de un inhibidor sobre la colonización y la enfermedad producida por cepas virulentas y avirulentas de Staphylococcus hyicus. En presencia de S. chromogenes la colonización de cepas virulentas se redujo a una milésima parte y la aparición de lesiones se retrasó 7 días. La capacidad de cepas avirulentas de S. hyicus para colonizar la piel se vió fuertemente reducida y las poblaciones bacterianas eran prácticamente no detectables a los 6 días de la inoculación.