Which organism is commonly associated with recalls of disinfectants due to its ubiquity and resistance to many disinfectants, and is a hospital-associated opportunistic pathogen?

• A. Bordetella bronchiseptica
• B. Klebsiella pneumoniae
• C. Pseudomonas aeruginosa
• D. Serratia marcescens

Answer: (C)

The main idea here is that some organisms persist in the healthcare environment and resist many disinfectants, making them notable culprits for hospital-associated issues and even product recalls. Pseudomonas aeruginosa is the classic example. It is ubiquitous in nature—found widely in water, soil, and damp places—and in hospitals it thrives in moist niches such as sinks, drains, humidifiers, and wet equipment. Its ability to form biofilms helps protect it from disinfectants, and it has intrinsic resistance mechanisms like low outer membrane permeability and active efflux pumps, which can be augmented by acquired resistance. This combination makes it unusually persistent and difficult to eradicate from clinical settings. As an opportunistic pathogen, it readily causes infections in hospitalized or immunocompromised patients, including pneumonia, bloodstream infections, and device-associated infections. The other organisms listed can cause hospital infections as well, but they do not fit as neatly with the pattern of widespread environmental presence and strong resistance to disinfectants that Pseudomonas aeruginosa demonstrates.