Biofilm formation and isolation of Staphylococcus aureus from blood cultures of dental patients undergoing oral surgical procedures

ABSTRACT

The objective of this study was the detection and separation of S. aureus from blood cultures of patients undergoing oral surgical procedures. Antibiotic sensitivity pattern and biofilm formation of S. aureus were also performed. Total 250 patients undergoing oral surgical procedures were selected for bacteriological examination. 5ml of Blood sample was collected in blood culture bottles containing tryptone soya broth. Blood sample was incubated at 37[degree sign] C for 7 days and after incubation subculturing was done on appropriate Media. The plates were then incubated at 37[degree sign]C aerobically for 24 hours, after which isolated colonies were obtained. S.aureus was identified by Gram staining, colony morphology, pigment production, catalase, coagulase and often biochemical tests. Antibiotic susceptibility was performed by disc diffusion technique on isosensitivity agar. Strains of S.aureus were used for biofilm formation by simple tubemethod. With the help of spectrophotometer at 570 nm optical density was measured. S.aureus [ATTC2523] was analyzed for biofilm production. Bacterial isolates in descending order were S.aureus 56%, E.coli 25%, Pseudomonas spp. 13%, S.typhi 4%and Shigella spp2%. S.aureus was resistant to different antibiotics. Biofilm production of S.aureus was detected in 16.17%of the S.aureus and mostly in association with antibiotic resistant bacteria. S.aureus was the predominant group of bacteria isolated from blood cultures of dental patients. Increased antibiotic resistance of S.aureus may be due to biofilm production resulting in persistent dental infections