Final answer:
The three first-line antibiotics for treating acute cystitis include Nitrofurantoin, a combination of trimethoprim and sulfamethoxazole, and Fosfomycin, chosen based on effectiveness and bacterial resistance patterns.
Step-by-step explanation:
The first-line antibiotics for acute cystitis generally include Nitrofurantoin, a combination of trimethoprim and sulfamethoxazole (also known as TMP-SMX), and Fosfomycin. Nitrofurantoin is often preferred for its specific effectiveness against the common uropathogens like Escherichia coli and low resistance rates. TMP-SMX is another effective option, but its use may be limited by local resistance patterns or patient allergies.
Fosfomycin has a broad range of activity against common uropathogens including multi-drug resistant strains and is given as a single oral dose. For cases where resistance is noted, as with the case of Marisa's infection caused by resistant Klebsiella pneumoniae, alternative antibiotics based on susceptibility testing would be necessary.