## 2 Results
### Antimicrobial Susceptibility Testing  
The peptides in Table 1 were screened for antibacterial activity. The benefit of screening peptides for activity first before performing a full MIC analysis for each one is to identify those that possess inhibitory effects at a relatively high concentration (100 \(\upmu\)g/mL)  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Name**} & \multicolumn{2}{c}{**Ferguson**} & \multicolumn{3}{c}{**CAMPR3**} & \multicolumn{3}{c}{**ClassAMP**} & \multirow{2}{*}{**DBAASP**} & \multirow{2}{*}{**PepVAE3**} \\ \cline{2-2} \cline{5-9}  & **SVM** & **SVM** & & & & & & \\ \hline HRZN-13 & 1 & 1.00 & 1.00 & AMP & 0.99 & 0.99 & 1.00 & AMP & AMP \\ \hline HRZN-14 & 1 & 0.99 & 0.99 & AMP & 0.99 & 0.99 & 1.00 & AMP & AMP \\ \hline HRZN-15 & 0.98 & 0.96 & 0.99 & AMP & 1.00 & 0.99 & 1.00 & AMP & AMP \\ \hline HRZN-16 & 1 & 1.00 & 0.98 & AMP & 1.00 & 0.96 & 0.99 & AMP & AMP \\ \hline HRZN-17 & 1 & 0.93 & **0.60** & AMP & 0.99 & 0.94 & 0.96 & AMP & AMP \\ \hline IDR-1018 & **0.15** & 0.99 & 0.97 & AMP & 0.99 & 0.97 & 0.97 & Non-AMP & AMP \\ \hline LL-37 & 1 & **0.76** & **0.75** & AMP & **0.77** & 0.97 & 0.95 & AMP & AMP \\ \hline \hline \end{tabular}
\end{table}
Table 2: Antimicrobial activity prediction results. Predictions that are lower than expected are bolded.  
and eliminate or downselect any inactive peptides. HRZN peptides were screened for antimicrobial activity at 100 \(\mathrm{\SIUnitSymbolMicro\text{$\mu$g}}\)/mL against a panel of multidrug-resistant _A. baumanniii_ strains to quickly identify viable peptides for further analysis. All peptides inhibited the growth of MDR _A. baumanniii_ strains. Peptides that exhibited a growth-inhibitory effect at 100 \(\mathrm{\SIUnitSymbolMicro\text{$\mu$g}}\)/mL were then assessed in detail via an MIC assay against _A. baumanniii_ strains AB5075, BAA-1710, -1794, and -1800.  
After screening, a minimum inhibitory concentration assay, which measures the lowest concentration of a compound that inhibits the growth of bacteria, was performed on HRZN peptides against four _A. baumannii_ strains. These strains were selected in this study because they were isolated from different infection sites in humans including bone, blood, sputum, and trachea. Also, the strains have different antibiotic resistance profiles (e.g., AB5075 is susceptible to tetracycline, while BAA-1710, -1794, and -1800 are not) [58; 59; 60; 61]. AB5075 is proposed to be an MDR model strain for studying pathogenesis and antimicrobial testing [61].  
We followed the standardized method for testing AMP activity [62]. The strain AB5075 is highly resistant to multiple antibiotics including Amp/Sul, Amk, Azt, Cfp, Cfz, Cpr, Gen, Imi, Lev, and Tob [61]. HRZN-15 had the strongest antimicrobial activity, resulting in an MIC of 4 \(\mathrm{\SIUnitSymbolMicro\text{$\mu$g}}\)/mL (Table 3), followed by HRZN-16 and HRZN-17, which demonstrated an MIC of 16 and 32 \(\mathrm{\SIUnitSymbolMicro\text{$\mu$g}}\)/mL (Table 3) across the tested strains, respectively. On the other hand, HRZN-13 showed the weakest activity MIC 32-64 \(\mathrm{\SIUnitSymbolMicro\text{$\mu$g}}\)/mL (Table 3), and HRZN-14 exhibited variable MIC ranging from 16 to 64 \(\mathrm{\SIUnitSymbolMicro\text{$\mu$g}}\)/mL (Table 3). This result was not predicted by the computational analysis, which suggested that HRZN-17 might have the poorest activity. LL-37 and polymyxin B were used as controls for MIC determination and showed bacterial growth inhibition at 8-32 and 0.25-0.5 \(\mathrm{\SIUnitSymbolMicro\text{$\mu$g}}\)/mL (Table 3), respectively, which was in agreement with reported results, except for the MIC value of LL-37 against AB5075 [32; 63]. The full data for the MIC assays of _A. baumannii_ strains AB5075, BAA-1710, -1794, and -1800 are in the Supplementary Materials (Figures S2-S5).