Which statement is true?

Which statement is true?

• A. The organism that must obtain its oxygen from oxygen containing compounds is a facultative anaerobe.
• B. Puerperal sepsis is caused by Neisseria gonorrhoeae.
• C. Staphylococcus aureus is well known for causing nosocomial infections.
• D. Corynebacterium diphtheriae never causes pseudomembranes.

Answer: (C)

The concept here is why Staphylococcus aureus is a classic cause of hospital-acquired (nosocomial) infections. This organism is a frequent colonizer of human skin and the nasal passages, so it readily transfers to patients and surfaces in a hospital. Its versatility in causing disease shows up in many settings: wound and surgical-site infections, catheter-related infections, pneumonia, and bloodstream infections. A big part of its notoriety in hospitals comes from its ability to form biofilms on indwelling devices and from antibiotic resistance, notably MRSA, which makes infections harder to treat and control. These factors together explain why Staphylococcus aureus is well known for nosocomial infections. The other statements don’t fit as well. An organism that must obtain oxygen from oxygen-containing compounds describes an obligate aerobe, not a facultative anaerobe, which can grow with or without oxygen. Puerperal sepsis is classically associated with organisms like Streptococcus species from the birth canal, not Neisseria gonorrhoeae. Corynebacterium diphtheriae does form a pseudomembrane in the throat during infection, so saying it never causes pseudomembranes is inaccurate.

The concept here is why Staphylococcus aureus is a classic cause of hospital-acquired (nosocomial) infections. This organism is a frequent colonizer of human skin and the nasal passages, so it readily transfers to patients and surfaces in a hospital. Its versatility in causing disease shows up in many settings: wound and surgical-site infections, catheter-related infections, pneumonia, and bloodstream infections. A big part of its notoriety in hospitals comes from its ability to form biofilms on indwelling devices and from antibiotic resistance, notably MRSA, which makes infections harder to treat and control. These factors together explain why Staphylococcus aureus is well known for nosocomial infections.

The other statements don’t fit as well. An organism that must obtain oxygen from oxygen-containing compounds describes an obligate aerobe, not a facultative anaerobe, which can grow with or without oxygen. Puerperal sepsis is classically associated with organisms like Streptococcus species from the birth canal, not Neisseria gonorrhoeae. Corynebacterium diphtheriae does form a pseudomembrane in the throat during infection, so saying it never causes pseudomembranes is inaccurate.