Antimicrobial Susceptibility Profile of Market-Sold Synthetic Antibiotic Discs Against Bacillus subtilis and Klebsiella pneumoniae
DOI:
https://doi.org/10.63561/jabs.v2i4.1003Keywords:
Bacillus Subtilis, Klebsiella Pneumonia, Antibiotic, Inhibition Zone, LevofloxacinAbstract
In the 21st century, one of the major global health challenges is the increasing threat of antimicrobial resistance, largely resulting from the overuse and misuse of antibiotics in both clinical and community settings. Seven (7) synthetic antibiotic drugs—namely Augmentin, amoxicillin, ciprofloxacin, cefotaxime, erythromycin, gentamicin, and levofloxacin—were obtained from a laboratory store, Ado Jone Limited, Kano. Two clinical isolates, Bacillus subtilis and Klebsiella pneumoniae, were obtained from Manzanita Research Laboratory, located behind Opeyemi Filling Station, Kwara State. Mueller–Hinton agar was prepared and poured into forty-two (42) sterile Petri dishes. A saline solution was prepared to dilute the bacterial isolates, and the turbidity was adjusted to match the 0.5 McFarland standard. A sterile cotton swab was used to streak the diluted organisms evenly on the surface of the agar plates. Antibiotic discs were then placed on the inoculated plates alongside a control disc consisting of sterile filter paper soaked in distilled water. All inoculated plates were incubated at room temperature, and after 24 hours, the diameters of the zones of inhibition were measured using a vernier caliper. All tests were carried out in triplicate. The highest antibacterial activity against Bacillus subtilis, with a mean inhibition zone of 27.17 mm, was demonstrated by erythromycin, followed by levofloxacin (21.07 mm). Gentamicin (18.63 mm), cefotaxime (17.67 mm), and ciprofloxacin (17.63 mm) showed lower levels of activity. Augmentin produced no inhibition (0.00 mm), indicating resistance of B. subtilis to the antibiotic. For Klebsiella pneumoniae, levofloxacin recorded the highest activity with a mean inhibition zone of 45.87 mm, followed by gentamicin (33.10 mm) and amoxicillin (29.10 mm). Augmentin showed moderate inhibition (23.10 mm), while ciprofloxacin (19.40 mm) and cefotaxime (18.10 mm) exhibited the lowest antibacterial effects
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