2023-2024

Antibiotic Resistance in E. coli Through Repeated Exposure: A Comparative Study of Ampicillin, Tetracycline, and Ciprofloxacin

World Health Organization reported that antibiotic resistance is a serious worldwide threat to human health. The study investigates varying levels of resistance development among Escherichia coli (E. coli) bacteria exposed to three different modes of action antibiotics: Ampicillin, Tetracycline, and Ciprofloxacin. The goal is to raise awareness about the dangers of improper antibiotic use in healthcare and food industries. The antibiotic resistance test was conducted using the Kirby-Bauer disk diffusion susceptibility test with Muller Hinton Agar (MHA) plates. The procedure involved inoculating plates with E. coli, placing blank and 7 Ampicillin, 7 Tetracycline, and 5 Ciprofloxacin disks, and incubating at 37°C for 20-24 hours. After incubation, the size of the Zone of Inhibition (ZOI) was measured, and E. coli colonies were collected from both the ZOI edge and inside, immersed in saline, and repeated for seven exposures. Ampicillin exposure resulted in changes in the ZOI percentage, reaching 51.83% by day 7, while Tetracycline and Ciprofloxacin showed minimal changes, with ZOI percentage changes of 18.08% and 10.25%, respectively. Although minimal, a noticeable trend towards resistance was observed, supporting the hypothesis of varying resistance levels among antibiotics. Notably, E. coli demonstrated resistance to Ampicillin within four days, potentially due to β-lactamase release. Conversely, the absence of resistance to Tetracycline and Ciprofloxacin suggests the need for genetic mutations, which did not occur within our exposure duration. This project demonstrates the importance of using antibiotics properly to prevent antibiotic resistance, crucial for healthcare professionals and the food industry to avoid repeated exposure.