Acinetobacter baumannii biofilm: Antimicrobial resistance and mechanisms of action of antimicrobial peptides: Recent progress and challenges

Background: Acinetobacter baumannii is Gram-negative cocco-bacillus, which are significant nosocomial pathogens causing a wide range of infections like; bacteremia, pneumonia, meningitis and critical wound infections. A. baumannii infections are difficult to eradicate because of escalated antimicrobial resistance to almost all available antibiotics and the capability to synthesize biofilm. This resistance causes an increase in mortality, especially in patients of intensive care units. Antibiotic resistance in A. baumannii has elevated because of the acquisition of mobile genetic elements like; plasmids, transposons, and integrons which further resulted in transmission of extensive drug resistance. A. baumannii has been listed as a critical or high priority pathogen by the World Health Organization, which raised serious concern about discovery of novel or alternative therapeutic options. A. baumannii has got a unique attribute to develop tough biofilms on both biotic and abiotic surfaces. Formation of biofilm renders this bacterium survives at different stress conditions like; nutrients depletion, exposure to antibiotics and dry environment, which make them flourish in the healthcare settings. Antimicrobial peptides have been considered as new generation antibiotics a potential alternative therapeutic option with broad antimicrobial effects. Apart from antibacterial activity, antimicrobial peptides also bear anti-biofilm, and other activities like; immune regulation. The aim of the present review is to critically discuss the role of antimicrobial peptides in combating biofilm formation and antimicrobial resistance posed by A. baumannii in an attempting to look towards novel therapeutic opportunities.