National Center of Excellence in Molecular Biology (CEMB)
Abstract
Background: Biofilm formation in indwelling medical devices poses serious risk of infection and increases the likelihood of recurrence of infections. The study was carried out to identify the microbes which form biofilms on medical implants and are thus involved in nosocomial infections, to assess the potential of biofilm producing ability of these isolated microbes and to determine antibiotic resistance towards ampicillin, vancomycin ceftazidime, streptomycin and tetracycline.Methods: For this, 11 samples of 5 different implants were taken from Tertiary Care Hospital Multan, Pakistan. Bacteria were isolated and identified by culture plate method. Tryptone soy broth (TBS) media was used for biofilm development by microbes in plastic tubes. Developed biofilm in tubes was visualized with crystal violet staining method and then biofilm forming potential was estimated by measuring the optical density through spectrophotometer. Antibiotic susceptibility was done by Kirby Bauer disk diffusion method to determine the resistance and susceptibility pattern of biofilm producers.Results: Out of 11 different samples of indwelling medical devices, a total of 131 bacterial strains were isolated. The percentage of bacterial isolates which produced biofilms were Staphylococcus spp. (41%) followed by Escherichia coli (18%), Pseudomonas spp. (4%), Proteus spp. (7.2%), Klebsiella spp. (8.6%), Bacillus spp. (8.6%), Fusobacterium spp. (1.4%) Clostridium spp.(1.4%), Enterococcus spp. (7.2%) and Neisseria spp. (1.4%). Sixty-nine isolates were considered positive for biofilm formation while 58 were considered negative. The resistance was maximum against ampicillin (42%) followed by ceftazidime (17.1%), tetracycline (34%) and streptomycin (30%) while against vancomycin no resistance was observed.Conclusion: Biofilms produced on medical implants by different bacteria are considered to be the major cause of hospital acquired infections and are very difficult to eradicate. These biofilms associated implant infections are challenging to treat because of their resistance towards various antibiotic therapies. Therefore, some efficient methods of prevention of biofilm formation should be introduced.Keywords: Bacterial biofilms; Biofilm associated infections; Medical implants; Hospital acquired infections; Antibiotic resistance
