Impact of Diameter of Inhibition in Crowded Plates on the in vitro Inhibitory Strength of Potential Antibiotic-Producing Bacteria Isolated from Some Natural Habitats

Antimicrobial resistance is a global problem, and efforts to replace failing antibiotics are crucial. We investigated the impact of the diameter of inhibition (mm) in crowded plates of potential antibiotic-producing bacteria on their in-vitro inhibitory strength. Our previous research identified 12 potential antibiotic-producing bacteria from natural habitats and obtained their diameters of inhibition in preliminary crowded plates. The potential candidates were further challenged with some pathogenic microbes by the Agar-well diffusion technique to test their strength. The results showed that the diameter of inhibition of the potential antibiotic-producing isolates obtained at the crowded plate technique level was not a predictor of the potency of potential antibiotic-producing bacteria (rs = 0.52, P = 0.08). In summary, the selection of potent candidate microbes for the development of new antimicrobial compounds against multidrug-resistant pathogens cannot be determined based on the diameter of inhibition in a preliminary investigation using the crowded plate technique. Further studies involving complementary techniques are necessary to determine the best potential candidate organisms for the development of novel antimicrobial compounds.