Antimicrobial Resistance and Quorum Sensing Genes Detection among the Biofilm Forming Staphylococcus aureus Isolated from Admitted Patients of Dhaka Medical College Hospital, Dhaka, Bangladesh
Author(s): Noor-E-Jannat Tania, S. M. Shamsuzzaman, Aminul Islam
Staphylococcus aureus an infamous human pathogen, is a major cause of the community as well as healthcare associated infections. Staphylococcus aureus has the tendency to form biofilm. Biofilm formation usually increases antimicrobial resistance capacity which shows considerable challenges to successful eradication of infections. The aim of this study was to detect the biofilm forming Staphylococcus aureus phenotypically and to determine its association with drug resistance and also detect the prevalence of different types of quorum sensing genes among them. Out of 275 clinical samples, 75.64% were culture positive among which 21.63% Staphylococcus aureus were isolated by culture and biochemical tests. Biofilm producing Staphylococcus aureus were isolated by tissue culture plate method and tube method. Antimicrobial susceptibility tests were performed by the standard disc diffusion technique. PCR was done to detect agr genes and sequencing of agr-I gene was done. Tissue culture plate method was found superior to tube method for biofilm detection. Tissue culture plate method detected 71.11% and tube method detected 62.22% biofilm producers. Biofilm-producing Staphylococcus aureus showed higher resistance to oxacillin 53.13%, cefoxitin 46.88% and ampicillin 46.88% than non biofilm-producers. Among biofilm-producing Staphylococcus aureus, agr-I gene was predominant (46.88%) than other quorum sensing genes. The study provided insight into the higher proportion of antibiotic resistance among non-biofilm-producing Staphylococcus aureus than biofilm-producers. So, antibiotic resistance is not significantly associated with biofilm-production in Staphylococcus aureus.