Are there regions in the us in which ciprofloxacin is less effective that in others? what environmental factors influence its efficacy?

Yes: The effectiveness of an antibiotic depends on the sensitivity of the microbes that it is used against. This can vary quite a bit based on locations, but this is more from how antibiotics are used in your community, not environmental factors.

Yes: Antibiotic resistance varies by locality, for most antibiotics. Overuse of antibiotics is a common cause. Also, about 50% of antibiotic use in this country is in animal feed, which helps to cause more human infections & antibiotic resistance.You can check with your local hospital for antibiotic resistant rates. Resistance differs by bacteria type. See below: https://tinyurl.com/sgbppdw