Assessment of the Correlation Between Biofilm Formation and Resistance to Various Classes of Beta-Lactam Antibiotics

Bacterial biofilm assumes importance across various contexts, including chronic human infections, dental plaque, and infections associated with foreign bodies such as catheters. Pseudomonas aeruginosa, recognized for its biofilm-forming capacity, is implicated in the onset of diverse infections. This study aims to explore the correlation between biofilm production and resistance to distinct classes of beta-lactam antibiotics.

In this cross-sectional investigation, 113 wound samples from burn patients admitted to Tehran and Ahvaz hospitals in 2020 were collected. Pseudomonas aeruginosa strains were identified using conventional biochemical and molecular methods. Antibiotic resistance profiles were elucidated employing the disk diffusion method, while beta-lactamase genes were identified through polymerase chain reaction (PCR). Statistical analysis was conducted using SPSS 20 software.

Forty isolates of P. aeruginosa, all exhibiting biofilm-producing capabilities, were identified. Carbapenem resistance manifested in 16 isolates, with the predominant beta-lactamase genes being blaTEM (15 isolates), blaVIM (12 isolates), and blaCTX-M (8 isolates). The highest resistance was observed against cefotaxime, cefazolin, meropenem, imipenem, and piperacillin, with 16 strains displaying resistance to these antibiotics. In the examination of carbapenemase-producing isolates (40% of the isolates), robust adhesion capabilities were consistently observed, and none lacked biofilm formation.

Significant antibiotic resistance, particularly carbapenem resistance, was identified among P. aeruginosa isolates causing burn wound infections. The combination of carbapenem resistance with biofilm production poses a formidable challenge in managing infectious diseases. It is suggested that, in addition to combating microbial resistance, efforts should be directed towards the eradication of bacterial biofilm for effective treatment.