If a hospital patient's infection suddenly becomes resistant to multiple antibiotics after a roommate is treated for a separate infection, which mechanism is most likely?

💡 Explanation

Horizontal gene transfer, particularly via plasmids, facilitates the rapid spread of antibiotic resistance between bacteria because bacteria can acquire resistance genes from other bacteria, rather than relying solely on mutation or increased efflux. Therefore, horizontal transfer explains the rapid multi-drug resistance, rather than mutation or cell wall changes.

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