Tom Bocci's encounter with a bacterium he had never heard of began in April, when his doctor suggested a test for prostate cancer. Because the results appeared slightly abnormal, Mr. Bocci underwent a biopsy, taking antibiotics beforehand as a standard precaution against infection.
There was no problem with his prostate, it turned out. But a few days later, Mr. Bocci developed severe diarrhea, fever and vomiting. He grew dehydrated. Five days afterward, in a hospital emergency room, doctors diagnosed a Clostridium difficile infection.
Antibiotics appeared to squelch the infection but, as happens in 20 to 30 percent of cases, the symptoms returned with a vengeance as soon as he finished the drugs. Over several months, Mr. Bocci suffered from migraines, weakness, anxiety and hypertension.
Told to isolate himself, he warned family members not to visit his home in Troy, Mich.; his wife, Wendy, moved into a spare bedroom. He lost 30 pounds. After the third recurrence, "I really thought I was going to die," Mr. Bocci, now 71, said. "And sometimes I felt I wanted to."