Nonspecific defense mechanisms in dogs during experimental staphylococcal infection

The aim of our study was to evaluate nonspecific defense mechanisms (phagocytosis and acute phase response) in dogs during an experimental infection caused by subcutaneous application of Staphylococcus aureus (1x108 CFU/mL). The neutrophils phagocytosis (evaluated by fluorescein isothiocyanate labeled Staphylococcus aureus) is activated at 48 h and the phagocytic number remained high at the 72-nd h of infection. During the early stage of the infection process (between the 2-nd and 24-th h) the absolute segmented neutrophil count, the absolute band count, band-neutrophyl ratio, tend to have high sensitivity, whereas an abnormal leukocyte count is registered at 48 h. Fibrinogen increase is registered the earliest (at 24-th h). Its concentrations remain high till the end of the study. The changes in the blood protein profiles show that the α2-globulin fraction rises at the 48-th and 72-nd h. Albumin was significantly lower at 72 h compared to the baseline values. There are no statistically significant changes in the total protein, A/G ratio and sialic acid, which we determined. The obtained data about the red blood cell parameters shows that Staphylococcus aureus induces a moderate anaemia when applied in dogs. Deviations are also registered in the mean corpuscular hemoglobin, while the other red blood cell indices - mean corpuscular hemoglobin concentration and mean corpuscular volume, are within normal reference ranges. We conclude that it is always better to combine immunological, hematological and biochemical indices. The key is to choose tests that are frequently used and to ensure more rapid information about the infectious process.