Evaluation of different detection methods of biofilm formation in the clinical isolates

Abstract

BACKGROUND: Microorganisms growing in a biofilm are associated with chronic and recurrent human infections and are highly resistant to antimicrobial agents. There are various methods to detect biofilm production like Tissue Culture Plate (TCP), Tube method (TM), Congo Red Agar method (CRA), bioluminescent assay, piezoelectric sensors, and fluorescent microscopic examination. OBJECTIVE: This study was conducted to compare three methods for the detection of biofilms. METHOD: The study was carried out at the Department of Microbiology, Army Medical College, National University of Sciences and Technology, Pakistan, from January 2010 to June 2010. A total of 110 clinical isolates were subjected to biofilm detection methods. Isolates were identified by standard microbiological procedures. Biofilm detection was tested by TCP, TM and CRA. Antibiotic susceptibility test of biofilm producing bacteria was performed by using the Kirby-Bauer disc diffusion technique according to CLSI guidelines. RESULTS: The TCP method was considered to be superior to TM and CRA. From the total of 110 clinical isolates, TCP method detected 22.7% as high, 41% moderate and 36.3% as weak or non-biofilm producers. We have observed higher antibiotic resistance in biofilm producing bacteria than non-biofilm producers. CONCLUSION: We can conclude from our study that the TCP method is a more quantitative and reliable method for the detection of biofilm forming microorganisms as compared to TM and CRA methods, and it can be recommended as a general screening method for detection of biofilm producing bacteria in laboratories

Effect of Green Synthesized Silver Nanoparticles on Quorum Sensing Inhibition of Uti Pathogens

“…These AgNPs exhibited significant antimicrobial activity against the isolates. The results are in accordance to the previous reports by Hassan et al [15]. AgNPs also exhibited anti-QS activity by inhibiting the violacein production.…”

“…The supernatant was discarded and the pellet was dried to obtain purified nanoparticles. It was then dissolved in appropriate amount of dimethyl sulfoxide (DMSO) [15].…”

Prevalence of MRSA and Biofilm Associated Gene among Clinical Isolates of Staphylococci

“…Excess stain was removed by using sterile water and attached dye was solubilized with 95% ethanol and the optical density (OD) of the adherent biofilm was read at 570nm by using ELISA reader (Biotek Epoch). The experiment was performed in triplicate (Hassan et al, 2011). The isolates of biofilm production were categorized into non/Weak, moderate and strong producers (Table 1).…”

Current in vitro assay to determine bacterial biofilm formation of clinical isolates

“…When compared to TM and CRA methods, TCP can be recommended as a general screening method for detection of biofilm producing bacteria in laboratories. 18 It was found to be most sensitive, accurate and reproducible screening method for detection of biofilm formation and has the advantage of being a quantitative model to study the adherence of microorganism on biomedical devices. 11 In addition, electron micrograph images correlate well with the biofilm production as observed by TM while CRA is not recommended for investigation of biofilm formation in Staphylococcus aureus.…”