Recurrent Staphylococcal Skin Infection:
What Do We Know?
Most dogs with recurrent staphylococcal skin infection have a specific and definable reason for the recurrence. Two examples of common and important reasons are:
Allergic skin diseases – in this case, alterations in the skin physiology and trauma to the skin from scratching leads to colonization by and infection with Staphylococcus species.
Seborrheic skin diseases – accumulation of excess skin cells and lipid on the skin surface provides an abundant nutrient source for normal skin flora such as staphylococcal bacteria, and leads to recurring infections.
However, in some dogs with recurrent skin infections the cause cannot be determined. We term this condition “idiopathic recurrent pyoderma.”
The pathogenesis of idiopathic recurrent staphylococcal pyoderma is not well understood. Many authors have implicated some kind of immunodeficiency state that allows repeated infections to occur. However, dogs with recurrent pyoderma typically do not contract other infections more frequently than other dogs. Thus, recurrent pyoderma does not appear to be associated with a general state of immunodeficiency. More likely, it is associated with more limited alterations in the dog’s immune response to staphylococci; most of these alterations remain to be defined.
How Does Staphylococcus Phage Lysate (SPL) Work?
SPL has a variety of effects on the immune response that may have clinical relevance. Some of these effects have marked species variation. Effects of SPL include antigen-specific and nonspecific phenomena, and involve both cellular and humoral immune responses. Some of the early research describing these responses is listed below. In dogs, SPL does not seem to act as a vaccine to induce “protective immunity” against staphylococci. In fact, repeated treatment with SPL does not necessarily promote an antibody response against staphylococcal organisms. Rather, in dogs, SPL seems to have a more general immunomodulatory effect, which requires continued and repeated dosing to remain effective. Recently, investigations of the actions of SPL on canine immune function suggest that at least part of its action may involve inducing release of cytokines such as interferon-gamma from lymphocytes.
The following is a list of references discussing the actions of SPL in dogs and in other animal models.
1. Morales CA, Schultz KT, DeBoer DJ, Anti-staphlococcal antibodies in dogs with recurrent staphylococcal pyoderma. Vet. Immunol Immunopathol 1994; 42(2): 137-47.