## 2 Results and Discussion
### AMP Type  
#### 2.5.1 Single AMP Type  
The human cathelcidin LL-37 was one of the popular AMPs to be studied during the review period, with LL-37 being one of the few human bactericidal peptides with potent anti-staphylococcal activity (one of the main bacteria associated with orthopaedic implant infections). Using in vitro studies and static biofilm models, [PERSON] et al. showed that LL-37 had significant anti-staphylococcal effects and a 'destructive effect' on _S. aureus_ biofilm formed on a titanium alloy surface (as a proxy for a prosthesis) [99]. [PERSON] et al. examined the effects of LL-37 and human lactoferricin AMPs on anaerobic biofilms associated with oral diseases [100]. This was performed in combination with the antibiotics amoxicillin, cindamycin, and metronidazoleabe using facultative and obligate anaerobic polymicrobial biofilms. The inclusion of LL-37 or lactoferricin enhanced the reduction in both obligate and facultative anaerobic biofilms by these antibiotics. Synthetic AMP TC19 is another human AMP studied, with it being derived from Thromboidin-1-derived peptide L3 found in human blood platelets. TC19 killed _Enterobacter cloace_, _Enterococcus ficeum_, _S. aureus_, _K. pneumoniae_, and _A. baumannii_. Topical application of TC19-containing hypromellose gel significantly reduced MDR _A. baumannii_ and MRSA in a murine superficial wound infection model [101]. Another human AMP studied was 'Reactive Oxygen Species Modulator 1' (Romo1). Romo1 was observed to eradicate entero-invasive _E. coli_ from HeLa cells and a single dose of AMPR-11 (derived from Romo1) appeared to have similar efficacy to multiple doses of impenem in a mouse model of sepsis when using _A. baumannii_, _P. aeruginosa_, _K. pneumoniae_, and _S. aureus_[102]. As well as humans, insects are also a source of AMPs as [PERSON] et al. utilized 36 synthetically produced black soldier fly (_Hernatia illucens_) AMPs. Two cecropins, Hill-Cec1 and Hill-Cec10, were found to be bactericidal with promising activity against _K. pneumoniae_ and MDR _P. aeruginosa_. However, although able to prevent _P. aeruginosa_ biofilm formation, they could not eradicate existing biofilms [103]. Continuing with a sea life theme, small peptides of 10-22 aa length (Bip_AA_2 and Bip_AA_5) were associated with a significant decrease in the production of biofilm by _Klebsiella oxytocin_. Bip_AA_2 and Bip_AA_5 were obtained via cDNA expression from the Cnidarian moon jellyfish _Aurelia aurita_[104]. [PERSON] et al. purified and characterized an AMP crustin from the green tiger shrimp _Penaus semisilcatus_[105]. This crustin showed antibacterial activity against Gram-positive _Bacillus thuringiensis_ and _B. pumilis_ when compared to Gram-negative _Vibrio parahaemolyticus_ and _V. alginolyticus_. From the octopus (specifically _Octopus minor_), the AMP octopromycin inhibited the swarming swimming, and alginate production of _A. baumannii_ via anti-quorum sensing activity. The AMP also significantly reduced the mass and structure of _A. baumannii_ biofilm and killed persister cells [106]. Investigation of the AMP capitellacin from the marine polychaeta _Capitella teleta_ indicated that this AMP appeared to have a 'detergent-like' action on target cells rather than binding to a particular cellular target. Furthermore, after 21 days of exposure, capitellacin did not generate resistance in _E. coli_ with the AMP also preventing and destroying mature _E. coli_ biofilm [107]. Finally, with respect to aquatic life, Piscidin AMPs are derived from several species of fish with [PERSON] et al. investigating six analogues of Oreech-2 that were derived from tilapia (_Oreechromis nilictus_) [108]. This species ranks as one of the most farmed fish species globally. Two of these analogues (ZN-5 and ZN-6) were bactericidal and could inhibit biofilms of _S. aureus_ ATCC25923. [PERSON] et al. studied Piscidin AMPs (piscidin 1, piscidin 3, piscidin 4, and piscidin 5) from various bass species of fish.