Nitrofurantoin resistance is seen in which organism?

Prepare for the CAMLPR Microbiology Test. Utilize flashcards and engaging multiple-choice questions, each equipped with descriptions and explanations. Ready yourself for an excellent performance!

Nitrofurantoin is used mainly for uncomplicated lower urinary tract infections because it concentrates in urine and is active against a specific set of urinary pathogens. The drug works when it’s reduced inside susceptible bacteria to reactive intermediates that damage DNA and other cellular components.

Proteus mirabilis tends to be resistant to nitrofurantoin, so it’s the organism you’d expect to see nitrofurantoin resistance with. This limits nitrofurantoin’s usefulness for UTIs caused by Proteus. In contrast, organisms like Pseudomonas aeruginosa are typically resistant due to intrinsic factors that prevent drug entry or promote efflux, while common urinary pathogens such as Staphylococcus aureus and Enterococcus faecalis are generally susceptible in uncomplicated cases, which is why Proteus stands out as the usual resistant organism in this context.