Staphylococcus intermedius binding to immobilized fibrinogen, fibronectin and cytokeratin in vitro

Virulence factors in coagulase-positive staphylococci of veterinary interest other than Staphylococcus aureus

Coagulase-positive Staphylococci (CoPS) can exist as commensals in humans, companion and food-producing animals, but can cause severe or even lethal diseases. Exchange of these bacteria between humans and animals has been described. Special attention has been focused on Methicillin-Resistant Staphylococcus aureus, but other CoPS can also represent an important threat. In addition to significant antimicrobial resistance, these bacteria may carry a plethora of virulence factors - molecules that allow bacteria to establish on or within a host and increase their ability to cause disease. These virulence factors have been widely described in S. aureus but information about other species of CoPS is scarce. The aim of this paper is to review the recent literature about the virulence factors of non-aureus CoPS of animal origin. Their possible effects on human health are also described. The role and prevalence of different virulence factors including leukocidins, hemolysins, adhesins, enterotoxins, exfoliative and toxic shock syndrome toxins as well as superantigen-like proteins are addressed. The effect of these virulence factors on human health is also described. The possibility of misdiagnosis of species of CoPS has been demonstrated in human clinical samples. Prevalence of zoonotic infections could be higher than thought and medical laboratories should be aware of these other staphylococcal species. In keeping with the ‘One Health’ approach to animal and human disease, medical professionals, veterinarians and health workers should be aware of the risks derived from exposure to these bacteria in people in close contact with animals, including pet owners, farmers and veterinarians themselves.

Comparison of once-daily versus twice-weekly terbinafine administration for the treatment of canine Malassezia dermatitis - a pilot study

BACKGROUND

Terbinafine, an allylamine antifungal, is used in pulsatile dose regimens for superficial mycoses in human medicine.

OBJECTIVES

To compare the clinical efficacy of twice-weekly versus once-daily terbinafine administration to determine whether preliminary proof-of-concept evidence exists for pulsatile administration of terbinafine in the treatment of canine Malassezia dermatitis and to determine whether twice-weekly treatment results in fewer clinical and owner-perceived adverse events.

ANIMALS

Twenty client-owned dogs with Malassezia dermatitis.

METHODS

In this randomized, single-blinded clinical trial, dogs were randomly assigned to receive terbinafine (30 mg/kg) either once daily for 21 days (n = 10) or once daily on two consecutive days per week for six doses (n = 10). On day 0 and day 21, a mean yeast count was calculated from eight anatomical locations via adhesive tape-strip cytology, clinical lesion scores were assigned to the same locations, and owners assessed pruritus using a visual analog scale.

RESULTS

There was no significant difference between treatment groups with respect to the reduction in mean yeast count (P = 0.343) and clinical lesion scores (P = 0.887). Pruritus measured by visual analog scale was significantly decreased in the twice-weekly treatment group compared with the daily treatment group (P = 0.047). Seven of 20 dogs had a clinically measurable or owner-reported adverse event during treatment that included gastrointestinal disturbances, excessive panting and elevated hepatic enzymes, with no significant difference noted between treatment groups.

CONCLUSIONS AND CLINICAL IMPORTANCE

This pilot study indicates that twice-weekly terbinafine administration may be an effective alternative treatment for canine Malassezia dermatitis and merits further investigation.

Genomic and surface proteomic analysis of the canine pathogen Staphylococcus pseudintermedius reveals proteins that mediate adherence to the extracellular matrix

Cell wall-associated (CWA) proteins made by Gram-positive pathogens play a fundamental role in pathogenesis. Staphylococcus pseudintermedius is a major animal pathogen responsible for the canine skin disease bacterial pyoderma. Here, we describe the bioinformatic analysis of the family of 18 predicted CWA proteins encoded in the genome of S. pseudintermedius strain ED99 and determine their distribution among a phylogenetically diverse panel of S. pseudintermedius clinical isolates and closely related species of the Staphylococcus intermedius group. In parallel, we employed a proteomic approach to identify proteins presented on the surface of strain ED99 in vitro, revealing a total of 60 surface-localized proteins in one or more phases of growth, including 6 of the 18 genome-predicted CWA proteins. Based on these analyses, we selected two CWA proteins (SpsD and SpsL) encoded by all strains examined and investigated their capacity to mediate adherence to extracellular matrix proteins. We discovered that SpsD and SpsL mediated binding of a heterologous host, Lactococcus lactis, to fibrinogen and fibronectin and that SpsD mediated binding to cytokeratin 10, a major constituent of mammalian skin. Of note, the interaction with fibrinogen was host-species dependent, suggestive of a role for SpsD and SpsL in the host tropism of S. pseudintermedius. Finally, we identified IgG specific for SpsD and SpsL in sera from dogs with bacterial pyoderma, implying that both proteins are expressed during infection. The combined genomic and proteomic approach employed in the current study has revealed novel host-pathogen interactions which represent candidate therapeutic targets for the control of bacterial pyoderma.

Surface coating strategies to prevent biofilm formation on implant surfaces

Implant surfaces should ideally be designed to promote the attachment of target tissue cells; at the same time, they should prevent bacterial adhesion, achievable through modification strategies comprising three lines of defense. As the first criterion, selective adhesion can be realized by means of non-adhesive coatings that can be functionalized with small peptides, thereby supporting osteogenic cell attachment for implants in bone contact but not bacterial adhesion. The second line of defense, defined by bacterial survival, quorum sensing and biofilm formation, can be addressed by various antimicrobial substances that can be leaching or non-leaching. The possibility of a third line of defense, the disruption of an established biofilm, is just emerging. Since microorganisms are quite ''ingenious'' at finding ways to overcome a certain line of defense, the most promising solution might be a combination of all these antibacterial strategies. Coating systems that allow such different approaches to be combined are scarce. However, ultrathin multifunctional NCO-sP(EO-stat-PO)-based layers may represent a promising platform for such an integrated approach.