Acinetobacter baumannii Biofilm Formation: Association with Antimicrobial Resistance and Prolonged Survival under Desiccation

Abstract

Biofilm-forming multidrug-resistant Acinetobacter baumannii has emerged as a global pathogen. This study investigated the impact of biofilm formation by A. baumannii on antimicrobial resistance and prolonged survival under desiccation, which is essential for effective infection control of A. baumannii in hospital settings. Seventy-eight clinical isolates of A. baumannii were identified, and antibiotic susceptibility profiles were assessed. All the isolates were investigated for their biofilm-forming abilities at 24 and 48h. The biofilm inhibitory concentrations of antibiotics were evaluated for selected biofilm-forming isolates to determine the influence of biofilm on antibiotic tolerance. The impact of biofilm formation on desiccation tolerance was also evaluated for up to 48days. The results revealed that out of 78 A. baumannii clinical isolates, 83% were MDR and 17% non-MDR. Overall, 79% of isolates formed high biofilm after 24h. The extent of biofilm formation gets significantly increased after 48h, and 87% of isolates formed high biofilm. It was observed that eradicating mature biofilm requires up to a thousandfold higher concentration of antibiotics than MICs, and biofilm-forming isolates can survive for a prolonged period under desiccation. In conclusion, our findings revealed that both MDR and non-MDR isolates of A. baumannii could form biofilms on abiotic surfaces. A. baumannii biofilms contribute to endurance in the presence of antimicrobials and desiccation conditions, which are significant trouble for hospital patient care management. The present findings may offer insights for developing preventive measures to tackle biofilm-associated A. baumannii infection.