Chapter 7, Problem 1CCS

Clinical Case Study Deadly Horizontal Gene Transfer

Sarah might have been 85 years old, but her mind was still sharp; it was her body that was failing. After she broke her hip by falling in the bathroom, she had succumbed to a series of complications that ultimately required admittance to a large university-associated hospital in New York City. Treatment necessitated a urinary catheter, a feeding tube, and intensive antibiotic therapy. While hospitalized, she acquired a life-threatening urinary tract infection with multi-drug-resistant (MDR) Enterococcus faecium.

Enterococci are normal members of the microbiota of the colon, yet these Gram-positive bacteria have a propensity to acquire genes that convey resistance to antimicrobial drugs. As a result of such horizontal gene transfer, E. faecium has become an MDR bacterium- that is, a strain resistant to many different kinds of antimicrobials. Drug-resistant enterococci are a leading cause of healthcare-associated infections (nosocomial infections).

Physicians treated Sarah with a series of antimicrobial drugs, including metronidazole, penicillin, erythromycin, ciprofloxacin, and vancomycin, but to no avail. After 90 days of hospitalization, she died.

1. 1. Define healthcare-associated infection.
2. 2. What is the likely source of Sarah’s infection?
3. 3. List three ways by which E. faecium might have acquired genes for drug resistance.
4. 4. How can hospital personnel prevent the spread of resistant E. faecium throughout the hospital?