DEAR DR. ROACH: About one year ago, I had Clostridioides difficile (C. diff) that was treated with 125 mg of vancomycin for about four weeks. I had none of the usual risk factors, and the cause was never determined. I am 78 years old and in fair health.

Recently, my family doctor diagnosed me with prostatitis after ruling out a urinary tract infection when I noticed a burning sensation while urinating. I was prescribed 100 mg of doxycycline for two weeks.

I declined the medication and saw my urologist, who took another urine sample with plans to do a culture. I am waiting for the result. I do not have any pain, fever, chills, etc. I am not on any antibiotic at this time, on the advice of the urologist as the lab results are pending.

My concern is that for this possible infection and any future infections, I will need an antibiotic, therefore running the risk of getting recurrent C. diff. How significant is this risk? What should I do?

•R.M.

ANSWER: C. diff is an intestinal infection that typically causes watery diarrhea, sometimes with a fever. It often occurs when the microbiome (a collection of intestinal bacteria) is disrupted by an antibiotic. Some antibiotics are much more prone to cause C. diff than others. (Clindamycin and ampicillin are particularly problematic, while doxycycline is lower-risk. But no antibiotic is risk-free.) Some people do get C. diff without having risk factors.

A recurrence of C. diff is common after an initial episode, with about 20% of people having a recurrence. A recurrence is most likely within six months of the original episode. Among people who are given a higher-risk antibiotic within six months of the original C. diff infection, about 10% will have a recurrence.

Because you are more than six months away from your initial infection, and you are recommended a lower-risk antibiotic, your estimate of a recurrence would be less than this. I would guess that it’s below 5%.

Even though this number is relatively low, I still think you are wise to avoid antibiotics. There are times when it’s reasonable to avoid antibiotics, and your current prostate infection seems to be one.

There are nonantibiotic treatments available such as alpha blockers, anti-inflammatories, and phytotherapies like quercetin. However, if there is a clear necessity for antibiotics, I would not let the risk of C. diff stand in the way of the necessary treatment.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.

cornell.edu.