The effect of polyvalent mechanical bacterial lysate on the reduction of nasal Staphylococcus aureus carriage in children with pollen allergic rhinitis

Abstract

Background: Methicillin-resistant Staphylococcus aureus (MRSA) colonizing the nasal cavity has the ability to actively modulate the immune response in children suffering from seasonal allergic rhinitis (SAR). Aim: Assessment of nasal colonization by MRSA among children with SAR and the effect of polyvalent mechanical bacterial lysate (PMBL) on the reduction of MRSA colony growth in these children. Methods: 34 children with SAR caused by grass pollen were enrolled in the study. 19 children received PMBL (Ismigen®) during the grass pollen season, and the remaining patients received the placebo. SAR symptoms were recorded in the daily patient diary according to standard scoring systems (TNSS – total nasal symptom score, TOSS – total ocular symptom score). In addition, two nasal swabs were collected for bacteriological cultures during two follow-up visits (V1 - at the beginning, V3 - at the end of the grass pollen season). Results: In the PMBL group, there was a significant reduction in the severity of pollinosis symptoms compared to the control group. MRSA was found in over 35% of children enrolled in the study. There were no statistically significant differences in the growth of MRSA colonies in both compared groups between V1 and V3 (PMBL - 6 vs. 5 children; p>0.05), (placebo - 6 vs. 7 children; p>0.05). There were no significant differences in the intensity of colony growth (PMBL - Z=0.27, p>0.05; placebo - Z=0.17, p>0.05). Conclusion: PMBL improves the clinical course of SAR in school-aged children. However, this effect has not been shown to be related to the ability of PMBL to decolonize MRSA from the nose.