Lecturer I, Delta State University
PREVALENCE OF BIOFILMS AND ENTEROTOXINS PRODUCED BY STAPHYLOCOCCUS AUREUS-INDUCING PNEUMONIA
The emergence of recalcitrant strains of Staphylococcus aureus is also alarming and an awareness of the virulence has been shown to help prevent, combat or eradicate Staphylococcus aureus infections. This study aimed at evaluating the biofilm forming capacity of Staphylococcus aureus, prevalence of Staphylococcus aureus induced biofilms and enterotoxins as well as prevalence of Staphylococcus aureus induced pneumonia in south-south geopolitical zone, Nigeria. A total of 1500 clinical specimens (sputa) were collected from clinically diagnosed pneumonia patients in randomly selected health institutions in south-south geopolitical zone, Nigeria and cultured using selective medium for Staphylococci. Seventy nine (79) samples out of 1500 investigated yielded Stahylococcus aureus. The 79 clinical isolates were further screened for biofilm formation using crystal violet binding assay and for enterotoxins using Reverse Passive Latex Agglutination (RPLA) method. The results showed that prevalence of Staphylococcus aureus induced pneumonia in south-south geopolitical zone, Nigeria is low; but the biofilm forming capacity of Staphylococcus aureus is high with the highest and lowest mean biofilm thickness (absorbance) of 0.358±0.06 and 0.211±0.07 respectively. Also the results showed that the most prevalent Staphylococcus aureus enterotoxins in south-south geopolitical zone, Nigeria is Enterotoxin B. These findings are very important in monitoring the virulence and resistance patterns of Staphylococcus aureus.
Abstract: Staphylococcus aureus and Staphylococcus epidermidis are the most important etiological agents of biofilm associated-infections on indwelling medical devices. Biofilm infections may also develop independently of indwelling devices, e.g., in native valve endocarditis, bone tissue, and open wounds. After attachment to tissue or indwelling medical devices that have been conditioned with host plasma proteins, staphylococcal biofilms grow, and produce a specific environment which provides the conditions for cell-cell interaction and formation of multicellular communities. Bacteria living in biofilms express a variety of macromolecules, including exopolysaccharides, proteins, extracellular eDNA, and other polymers. The S. aureus surface protein C and G (SasC and SasG), clumping factor B (ClfB), serine aspartate repeat protein (SdrC), the biofilm-associated protein (Bap), and the fibronectin/fibrinogen-binding proteins (FnBPA and FnBPB) are individually implicated in biofilm matrix formation. In S. epidermidis, a protein named accumulation-associated protein (Aap) contributes to both the primary attachment phase and the establishment of intercellular connections by forming fibrils on the cell surface. In S. epidermidis, proteinaceous biofilm formation can also be mediated by the extracellular matrix binding protein (Embp) and S. epidermidis surface protein C (SesC). Additionally, multifunctional proteins such as extracellular adherence protein (Eap) and extracellular matrix protein binding protein (Emp) of S. aureus and the iron-regulated surface determinant protein C (IsdC) of S. lugdunensis can promote biofilm formation in iron-depleted conditions. This multitude of proteins intervene at different stages of biofilm formation with certain proteins contributing to biofilm accumulation and others mediating primary attachment to surfaces. This review examines the contribution of proteins to biofilm formation in Staphylococci. The potential to develop vaccines to prevent protein-dependent biofilm formation during staphylococcal infection is discussed.
Pub.: 30 Dec '14, Pinned: 17 Aug '17