The Role of Biofilms Produced by Streptococcus Pneumoniae Isolated from Patients with Upper Respiratory Infections on Avoiding Innate Immunity

Phagocytosis has been recognized as an important mechanism of the human innate immune response against infections .The aim of this experiment is to test the effect of biofilms produced by Streptococcus pneumoniae isolates as a cause agent of serious infections isolated from children in some Iraqi patients on avoiding some innate immunity aspects in vivo. Twenty five isolates obtained from sputum of children diagnosed with upper respiratory infections. Two methods were used to detect the ability of biofilms formation, Congo red agar and Tissue Culture Plate (CRA,TCP) on the other hand the capacity to resist some innate immunity mechanisms was evaluated by testing the Percentage of killing, Opsonization factor and phagocytic index. The results revealed different ability of isolates to form biofilms. 18(72%) producer by CRA, 16(64%) by TCP while 5(20%) weak by CRA and 9(36%) weak by TCP which reflected the different ability to affect by innate immunity as showed in the statistical analysis findings (P-value 0.05) that some isolates appeared strong ability to produce biofilms resisted the innate immunity mechanisms such as isolate numbered 22 showed 32% Bactericidal assay, 20% opsonization and 28% phagocytic index, while some others was sensitive and killed by innate immunity cells. From the results of this study it can be concluded that the Streptococcus pneumoniae isolates differed in their ability to form biofilms, the important factor in the avoiding some innate immunity aspects and high resistant.