Chitosan Nanoparticles: As an Anti-Biofilm Agent against Acinetobacter Strains baumannii Representing the Multidrug Resistance Phenotype

Acinetobacter baumannii (A. baumannii) is a non-fermentative gram-negative coccobacillus that shows high resistance to antimicrobial compounds. Biofilm formation is one of the essential features of many Acinetobacter species that leads to high antibiotic resistance. This study aimed to evaluate the ability of biofilm formation and determine the antibiofilm activity of chitosan nanoparticles in clinical isolates of A. baumannii.

This descriptive cross-sectional study was conducted in 2021 and investigated 100 isolates collected from different hospitals. Microscopic, biochemical, and molecular tests were performed to identify the bacteria. The antibiotic resistance pattern of the isolates was evaluated by the disk diffusion method against 10 antibiotics, and the ability to produce biofilm was evaluated by microtiter plate method. Subsequently, 16SrRNA and CsuA genes were identified by multiplex-PCR molecular methods. After the preparation of chitosan nanoparticles and determination of MIC concentration, antibiofilm activity was measured by plate microtiter, and Real-Time PCR was used to examine the expression of the CsuA gene involved in biofilm.

In this study, out of 100 isolates examined, 29 isolates were confirmed as A. baumannii. Among 29 isolates, ceftazidime had the highest drug resistance (75.86%). The CsuA gene was detected in 51.72% of the isolates. Moreover, using a microtiter plate and Real-Time PCR, the level of antibiotic activity of chitosan nanoparticles was determined at a significant level of P<0.01.

Considering the anti-biofilm effects found in the present study, it seems that chitosan nanoparticles can be used as a pharmaceutical candidate in the pharmaceutical industry.