Antibiotics report submission

Claim: Among the four antibiotics I tested, ciprofloxacin was the most effective against my bacterial sample.

Reasoning from data: Ciprofloxacin produced the largest zone of inhibition (22 mm), which means bacteria could not grow even fairly far from the disk. Ciprofloxacin works by blocking DNA gyrase, the enzyme bacteria need to copy their DNA, so the cells cannot divide. Penicillin gave a much smaller zone (9 mm) because it only blocks cell-wall building, and my sample may already make an enzyme that breaks penicillin down. The size of each zone tracks with how well each mechanism could attack these specific cells.

Resistance paragraph: If even a few cells in this population carry a mutation in the DNA gyrase gene, ciprofloxacin would stop killing them. Those survivors would divide and pass the resistance gene on, so over several rounds of treatment the 22 mm zone could shrink toward zero. The drug that looks best today is not guaranteed to be best next year.

Stewardship recommendation: Because resistance can erase an antibiotic's advantage, I recommend using the narrowest effective drug, finishing the full prescribed course, and saving last-resort antibiotics for cases where first-line drugs have failed. This keeps the strongest tools working longer.

Open question: I still want to know how many treatment cycles it takes before a resistant strain becomes the majority of the population.