Illness from C. difficile most commonly affects older adults in hospitals or in long-term care facilities and typically occurs after use of antibiotic medications.

However, studies show increasing rates of C. difficile infection among people traditionally not considered to be at high risk, such as young and healthy individuals who haven't used antibiotics and who haven't been in a health care facility.










Fecal microbiota transplantation (FMT) is highly effective in treating recurrent infections with Clostridioides difficile (formerly Clostridium difficile).

Although it has been assumed that the bacteria in the normal fecal flora are responsible for the therapeutic benefit of FMT, it was recently shown that a sterile filtrate from healthy stool donors also can cause remission of recurrent C. difficile infection. This suggests that the benefit of the sterile fecal filtrate may be due to its content of bacterial metabolites or enzymes.

[Probiotics are useful in diarrhea are linked to anti-infectious and immune modulation. The only clear role for probiotics is with antibiotic-associated diarrhea.]

Recently McDonald and colleagues (2018) carried out a study to determine whether exposure of the gut to antibiotics may kill bacteria that perform important functions of the intestinal microbial ecosystem and alter microbial metabolic pathways that promote C. difficile germination and growth. They found that stool samples of individuals treated with clindamycin had decreased valerate and deoxycholic acid concentrations and increased C. difficle viable counts. After stopping clindamycin, bile acid levels recovered but valerate levels did not. However, administration of FMT did restore valerate levels in the stool.

In a separate study in mice, they observed that valerate significantly inhibits C. difficile growth. There are several pathways that lead to normal valerate production, including anaerobic degradation of protein hydrolysates by gut bacteria—in particular Clostridium species.

Although the exact therapeutic dose of valerate is being investigated, this normal gut metabolite has the potential to be more acceptable than FMT.


McDonald  JAK et al: Inhibiting growth of Clostridioides difficile by restoring valerate, produced by the intestinal microbiota. Gastroenterology 155:1495, 2018. 
[PubMed: 30025704] 

Most people with pyelonephritis do not have complications if appropriately treated with bacteria-fighting medications called antibiotics.

In rare cases, pyelonephritis may cause permanent kidney scars, which can lead to chronic kidney disease, high blood pressure, and kidney failure. These problems usually occur in people with a structural problem in the urinary tract, kidney disease from other causes, or repeated episodes of pyelonephritis.

Infection in the kidneys may spread to the bloodstream—a serious condition called sepsis—though this is also uncommon.



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Content 11


The use of an alcohol-based hand rub would be inadequate after leaving the room of which of the following patients?

Next Question
You will be able to view all answers at the end of your quiz.

The correct answer is E. You answered C.

The answer is E. (Chap. 168) Nosocomial infections have reservoirs and sources just as do community-acquired pathogens. In hospitalized patients, cross-contamination (i.e., indirect spread of organisms from one patient to the next) accounts for many nosocomial infections. While hand hygiene is uniformly recommended for healthcare practitioners, adherence to hand washing is low, often due to time pressure, inconvenience, and skin damage. Because of improved adherence, alcohol-based hand rubs are now recommended for all heathcare workers except when hands are visibly soiled or after care of a patient with C difficile infection, whose spores may not be killed by alcohol and thus require thorough hand washing with soap and water.


C. difficile colitis has been linked to all of the following EXCEPT:

The correct answer is D.



Mr. Jenson is a 40-year-old man with a congenital bicuspid aortic valve who you have been seeing for more than a decade. You obtain an echocardiogram every other year to follow the progression of his disease knowing that bicuspid valves often develop stenosis or regurgitation requiring replacement in middle age. Given his specific congenital abnormality, what other anatomic structure is important to follow on his biannual echocardiograms?

Next Question
You will be able to view all answers at the end of your quiz.

The correct answer is A. You answered A.

The answer is A. (Chap. 282) Bicuspid aortic valve is among the most common of congenital heart cardiac abnormalities. Valvular function is often normal in early life and thus may escape detection. Due to abnormal flow dynamics through the bicuspid aortic valve, the valve leaflets can become rigid and fibrosed, leading to either stenosis or regurgitation. However, pathology in patients with bicuspid aortic valve is not limited to the valve alone. The ascending aorta is often dilated, misnamed “poststenotic” dilatation; this is due to histologic abnormalities of the aortic media and may result in aortic dissection. It is important to screen specifically for aortopathy because dissection is a common cause of sudden death in these patients.



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