## 3 Results and Discussion
### Antimicrobial Activity
This comprehensive analysis underscores the varying degrees of antimicrobial activity exhibited by the extracts against different bacterial strains, with notable differences between the pruning firewood and stem extracts, as well as the impact of the tested antibiotic on bacterial growth inhibition. The Table 7 provides a comprehensive overview of the RIZD (Relative Inhibition Zone Diameter) percentages for each variety based on the extracts derived from pruning firewood and stems. These results reveal instances where the percentages equate to 100, indicating that certain extracts possess comparable efficacy in inhibiting bacterial growth to the antibiotic utilized in the analysis. A notable example is observed for the MRSA MJMC 583 strain, with the extract from the pruning firewood of the Alfredoheiro variety displaying a %RIZD of 100. For the _A. baumannii_ MJMC 561 isolate, no results could be obtained due to the unique circumstances of the pruning firewood extracts (Alfrocheiro and Jaen) inhibiting bacterial growth while the antibiotic (gentamicin) exhibited no halos, rendering the calculation of %RIZD impossible. Extracts that did not exhibit inhibition of bacterial growth demonstrated a %RIZD value of 0. In the context of pruning firewood, the scarcity of relevant literature hinders direct comparison with these findings, as this wine by-product has not been previously analyzed for antimicrobial activity. This study, being preliminary, holds the potential to pave the way for innovative applications of this wine by-product as a natural alternative strategy to combat clinically relevant multi-resistant bacteria, thereby reducing reliance on conventional antibiotics. Indeed, the escalation of bacterial resistance rates has significantly compromised the efficacy of existing antibiotics. Considering this pressing global public health challenge, research into natural alternative compounds and complementary therapies has become paramount in addressing the mounting threat of antibiotic-resistant bacteria [22]. This imperative approach ensures a sustainable trajectory for healthcare and disease management [23]. Particularly, in human health, reducing the likelihood of resistance development guarantees the availability of effective treatment options for infec \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Bacterial Isolates** & **ALF PF** & **BM PF** & **Jaen PF** & **ALF S** & **BM S** & **Jaen S** & **DMSO 10\%** & **CN** & **10 \(\mu\)g** \\ \hline _Escherichia coli_ ATCC & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 16 \\ _Acinetobacter baumannii_ MJMC 525 & 0 & 0 & 0 & 0 & 0 & 0 & 10 \\ _Acinetobacter baumannii_ MJMC 561 & 7 & 0 & 7 & 0 & 0 & 0 & 0 \\ _Pseudomonas aeruginosa_ MJMC 526 & 0 & 0 & 0 & 0 & 0 & 0 & 25 \\ _Pseudomonas aeruginosa_ MJMC 553 & 11 & 10 & 12 & 10 & 0 & 0 & 25 \\ _Pseudomonas aeruginosa_ MJMC 559 & 12 & 10 & 13 & 11 & 0 & 0 & 0 & 26 \\ _Staphylococcus aureus_ ATCC & 12 & 10 & 12 & 10 & 7 & 9 & 0 & 21 \\ MRSA MJMC 534-B & 12 & 10 & 12 & 7 & 0 & 11 & 0 & 23 \\ MRSA MJMC 583 & 13 & 10 & 12 & 0 & 0 & 9 & 0 & 13 \\ \hline \hline \end{tabular}
\begin{tabular}{c} ALF, Alfrocheiro; BM, Borrado das Moscas; PF, Pruning Firewood; S, Stems; DMSO, dimethylsulfoxide; CN, gentamicin; MRSA, Methicillin-resistant _Staphylococcus aureus_; ATCC, American Type Culture Collection. \\ \end{tabular}
\end{table} 
Table 6: Halos of inhibition (mm) obtained for extracts of pruning firewood, stems, and negative and positive controls tested. tions, thereby upholding public health. Additionally, the adoption of natural compounds can yield favorable environmental and economic outcomes. From an environmental perspective, natural compounds often exhibit biodegradability and a reduced potential to foster antibiotic-resistant genes in the ecosystem [24; 25]. This aligns with efforts to mitigate environmental impacts. Furthermore, there are noteworthy economic implications. The pursuit of alternative antibacterial agents offers the potential to alleviate the economic burdens associated with antibiotic resistance [26; 27].