Acinetobacter baumannii is a Gram-negative, non-fermentable bacillus commonly found in nature and in humans, and is considered as one of the major nosocomial infection (Wang et al., 2014). Biofilm formation by A. baumannii strains facilitates their colonisation on surfaces, especially endotracheal tubes, indwelling catheters, and medically valuable tools (Duarte et al., 2016). Studies show that around 65–80% of human infections (mainly chronic infections) are caused by bacteria forming biofilms. This rate rises to 90% in burn wards and some types of drug-resistant infections (Wang et al., 2014). Microbial biofilms are formed when microbial cells adhere to the surfaces of complex biotic or abiotic origin encased in an autogenic polymeric exopolysaccharide matrix. This system structurally protects microbial communities from antimicrobial agents (Tajani et al., 2021, Tajani et al., 2023, Dolma et al., 2022). The rate of biofilm production in A. baumannii is roughly 80–91%, which is higher than that in other species (5–24%) (Abdi-Ali et al., 2014). According to the evidence (World Health Organisation, 2017b), these bacterial strains now have a higher level of resistance to antimicrobial antibiotics and strains. Currently, the rate of resistance to frequently used antibiotics is 84.96% (Ma et al., 2013). The death rate following an A. baumannii infection increases yearly and ranges from 10% to 43% in intensive care unit patients (Chopra et al., 2013), indicating that biofilm is a major pathogenicity feature (Bhargava et al., 2012). In 2017, world health organisation (WHO) introduced A. baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae as critical priority pathogens to indicate their importance and to guide research and development of new antibiotics (World Health Organisation, 2017a).

There are more than 50 recognised species of Acinetobacter, and while they are mostly harmless, small strains of these bacteria can cause illness in humans under favourable conditions (Harding et al., 2018). According to the findings of the studies, multiple drug resistant (MDR) A. baumannii infections are often identified by resistance to three or more antibiotic families of carbapenems, quinolones, cephalosporins, lactams, and aminoglycosides (Hujer et al., 2006). Various challenges have been encountered in drug research against bacteria and biofilms (Roy et al., 2018), and no potent anti-molecules against bacterial biofilms are currently available (Manner et al., 2013). Therefore, the finding of an antibacterial compound is of great significance in the field of biomedical research as it seeks to provide long-term solutions to biofilm-mediated infections.

Previous studies have shown that herbal active compounds are effective against planktonic and free-floating bacteria (Tiwari et al., 2015, Tiwari et al., 2016) and that these bioactive components will likely be effective against bacterial biofilms as well. Moreover, due to their chemical diversity and effectiveness, natural chemicals derived from plants are a good source of biofilm disruptors and quorum-sensing (QS) inhibitors (Koh et al., 2013, Carradori et al., 2020), which have shown to be effective against some major factors of bacterial virulence and antibiotic resistance (Guglielmi et al., 2020).

Although no plant-derived antibiotics with particular cellular targets have been discovered, modified natural antibiotics such as penicillin proved to be effective. So far, pharmaceutical or biotechnology companies have not been successful in producing strong antibiotics of plant origin. On the other hand, active plant compounds with antimicrobial properties work together more effectively compared to when there is only one plant-derived active ingredient, which is another reason for the lack of access to plant-based antibiotics (Tiwari et al., 2015). Interestingly, as pure compounds or standardised extracts, medicinal plant natural products offer an unimaginable diversity of chemical compounds for the development of new drugs (Sasidharan et al., 2011).

Regarding the role of medicinal plants in dealing with a wide variety of microorganisms, researchers have been searching for herbal compounds or effective herbal substances to combat A. baumannii. This systematic review aimed to assess the studies about A. baumannii, considering the antibacterial and anti-biofilm potential of medicinal plants against this harmful pathogen.