Infection Control · patient case question
Which characteristic of a chemical agent is used to establish that it qualifies as an intermediate-level disinfectant?
Patient case: Newly Diagnosed Tuberculosis
demo: 41-year-old male
chief: Presents to urgent dental care with severe pain from tooth #14.
history: Diagnosed with active pulmonary tuberculosis one week ago; started on therapy 3 days ago. Productive cough, night sweats, weight loss.
meds: Isoniazid, rifampin, pyrazinamide, ethambutol
findings: Tooth #14 with pulp necrosis and symptomatic apical periodontitis. Also requests a routine cleaning.
Show answer and explanation
Correct answer: C. Its ability to kill Mycobacterium tuberculosis
- A. Inactivating HBV alone is insufficient; the tuberculocidal claim is the recognized marker.
- B. Killing ordinary vegetative bacteria is the low-level disinfectant standard, met by quaternary ammonium compounds.
- C. Correct. Tuberculocidal activity is the benchmark that defines intermediate-level disinfection, because mycobacteria are unusually resistant to chemical agents and survive on surfaces for months.
- D. Sporicidal activity defines a sterilant or high-level disinfectant such as glutaraldehyde, not the intermediate level.
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