USMLE Forum Archives - USMLE Step 1 - 29
29
drspleen - 03-15-11 02:00
A hospital discovers that its intensive care unit is heavily contaminated with the bacteria shown in the image. It is noted to produce pyocyanin and is lactose non-fermenting. Which patient population is least at risk for developing a nosocomial infection?
* A. Patients with indwelling silver-coated urinary catheters
* B. Patients heterozygous for chloride ion channel gene mutations
* C. Patients with homozygous mutations of a chloride ion channel gene
* D. Mechanically ventilated patients
* E. Patients with 20% body surface area full thickness burns
drspleen - 03-15-11 02:00
A hospital discovers that its intensive care unit is heavily contaminated with the bacteria shown in the image. It is noted to produce pyocyanin and is lactose non-fermenting. Which patient population is least at risk for developing a nosocomial infection?
* A. Patients with indwelling silver-coated urinary catheters
* B. Patients heterozygous for chloride ion channel gene mutations
* C. Patients with homozygous mutations of a chloride ion channel gene
* D. Mechanically ventilated patients
* E. Patients with 20% body surface area full thickness burns
The correct answer and explanation will be available after you answer.
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#3
Re: 29 babbu5508 - 03-19-11 13:55 My answer is: b.
B. Patients heterozygous for chloride ion channel gene mutations are at least risk for developing pseudomaonal infections...
#4
Re: 29
drspleen - 03-21-11 18:25 The production of pyocyanin (blue-green pigment) and lactose non-fermentation, along with the environmental prevalence of this organism, point to Pseudomonas aeruginosa. P. aeruginosa is an opportunistic pathogen. Patients at risk are those with breaks in their mucosa, skin, or those who cannot clear respiratory secretions. These specifically include patients with CF, patients who are mechanically ventilated, patients with indwelling urinary catheters, or patients with burns. CF is an autosomal recessive disease, so someone who is heterozygous for a CFTR gene mutation is not at increased risk for CF-related infections such as Pseudomonas.
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