Comparison of the Analytical Methods Employed in the Detection of Biofilm-Forming Bacterial Pathogens

Abstract

Bacterial biofilm is a matrix of microorganisms, usually pathogenic that are incorporated in a polysaccharide structure. Biofilms usually confer resistance on bacteria, making their presence in infections detrimental. This study aimed at evaluating the sensitivity of three analytical methods (Tissue Culture plate-TCP, Tube method-TM and Congo Red Agar-CRA) in the detection of biofilms from clinical isolates as well as the antibiogram profile using disc diffusion method. A total of 100 isolated and microbiologically identified bacteria of clinical origin belonging to Staphylococcaceae, Enterobacteriaceae, Pseudomonaceae, Campylobacteriacae, Moraxellaceae and Streptococcaceae were screened for biofilm formation using the aforementioned analytical methods. Bacteria pathogen showed varying degrees of biofilm formation, of the three methods compared, the TCP was the most sensitive and further classified as, 28 (28%) strong, 20 (20%) moderate and 52 (52%) weak biofilm producers; Tube method detected 16 (16%) strong, 46 (46%) moderate and 38 (38%) weak biofilm producers while Congo red agar detected 14 (14%) strong, 46 (46%) moderate and 40 (40%) weak biofilm producers. The biofilm producers, especially the Gram negative bacteria exhibited multi-drug resistance to antibiotics used against Ciprofloxacin (85%), Amoxicilin (80%), Ceftriaxone (70%), Tobramycin (60%), Amikacin (10%) and Imipenem (10%). Succinctly, the results from this study showed that TCP was found to be most efficient method for biofilm detection. This may be considered as a screening method to detect pathogens for biofilm production, this may assist in better clinical management.