## 2 Results and Discussion
### Microbial Focus  
AMP-related research into both bacterial and fungal species associated with biofilm production continued in 2020-2023, covering a variety of aspects where the pathogen was the focus of AMP research. In this respect, the pathogens _S. aureus_ (25%), _P. aeruginosa_ (13%), and _C. albicans_/spp. (13%) were most frequently cited in AMP research (Table 1). _Enterococcus faecalis_  
Three publications specifically focused on _E. faecalis_, with [PERSON] et al. investigating the activity of AMP GH12 on this species. GH12 was found to inhibit biofilm formation and virulence, as well as killing these bacteria in an ex vivo tooth model [50]. Staying in the field of dentistry, [PERSON] et al. used two antifungal peptides, i.e., KP and L18R, to demonstrate impairment in the biofilm architecture of _E. faecalis_ on hydroxyapatite disks [51]. Finally, the cationic AMP lysozyme also appeared to reduce viable _E. faecalis_ in biofilms (more extracellular DNA and dead bacteria) [52]. _Escherichia coli_  
Enterotoxigenic _E. coli_ (ETEC) are responsible for large financial losses for pig farmers. Synthetic AMP GW-Q4 derivative Q4-15-1a exhibited dose-dependent anti-MDR ETEC activity in time-kill kinetic experiments. The minimum biofilm eradication concentration was found to be four-fold the minimal inhibitory concentration (MIC) and in an porcine intestinal epithelial cell model completely inhibited ETEC adhesion [53]. _Pseudomonas aeruginosa_  
Four publications focused on human defense peptides such as S100A12, human beta defensins (HBD)-2 and -3, and the cathelcidin-related peptide CRAMP in _Pseudomonas_ spp., which inhibit biofilm formation via different mechanisms. Whereas S100A12 inhibited the expression of genes involved in biofilm formation and the synthesis of the virulence factors pyoverdine and pyocyanin [54], the AMPs HBD-2 and -3 had no effects on biofilm-related gene expression but instead induced changes in the _P. aeruginosa_ outer membrane that hindered the transport of biofilm precursors into the extracellular space [55]. Stably infected Caco-2 intestinal cells expressing HBD-2 and HBD-3 showed antibiofilm activity against _P. aeruginosa_, indicating that therapeutic strategies that enhance endogenous cellular AMP production might be successful as antibiofilm therapy [56]. The treatment of _P. aeruginosa_ with CRAMP led to the dispersion of established biofilms by affecting exopolysaccharides, as well as promoting the flagellar motility of the bacteria inside the biofilm [57]. [PERSON] et al. generated melimine, a chimeric AMP from melittin and protamine, which inhibited biofilm formation by >75% at one-fold MIC by depolarizing the cell membranes of biofilm cells. Melimine, however, was only effective in eradicating established biofilms when combined with ciprofloxacin (\(\geq\)61% at one-fold MIC). Importantly, while exposing _P. aeruginosa_ \begin{table}
\begin{tabular}{l l} \hline \hline
**Organism** & **Number** \\ \hline _Staphylococcus aureus_/MRSA & 13 \\ _Pseudomonas aeruginosa_ & 8 \\ _Candida albicans_/spp. & 8 \\ _Streptococcus pneumoniae_/_mutants_/_oral_ & 5 \\ _Enterococcus faecalis_ & 3 \\ _Escherichia coli_ & 1 \\ _Acinetobacter baumannii_ & 2 \\ _Cryptococcus neoformans_ & 2 \\ _Staphylococcus epidermidis_ & 2 \\ _Actinobacillus pleuropneumonia_ & 1 \\ _Bacillus cereus_ & 1 \\ _Corynebacterium striatum_ & 1 \\ _Lactococcus lactis_ & 1 \\ _Mycoplasma pneumoniae_ & 1 \\ _Porhyromonas gingivalis_ & 1 \\ _Salmonella serovars_ & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Frequency of microorganisms associated with published ‘AMP and biofilm’ research where the pathogen was the focus of interest in the title (from January 2020 to September 2023). Two publications reported research on _S. aureus_/_S. epidermidis_ and _S. aureus_/_P. aeruginosa_.