Clostridium Difficile Infection of a Prosthetic Joint

Abstract & Commentary

Synopsis: A case of a novel infection with C. difficile of orthopedic hardware a year after its placement and the patient’s enteric infection is examined.

Source: McCarthy J, Stingemore N. Clostridium difficile infection of a prosthetic joint presenting 12 months after antibiotic-associated diarrhoea. J Infect 1999;39:94-96.

Disseminated infection due to Clostridium difficile is an anomaly. Case reports of such infection usually warrant publication so that we may remain wary of this ubiquitous pathogen whose reason for such limited invasiveness remains unclear. In this case report from the medicine department at Freemantle Hospital in Western Australia, the anomaly is augmented by the presence of a prosthetic hip. The unfortunate victim was an 83-year-old woman who had fractured her hip and required placement of a Richardson pin and plate (not actually a prosthetic hip!). She had some diarrhea during the admission, incurred a nosocomial pneumonia, and received therapy with ceftriaxone and clindamycin. Twelve days postoperatively she had a positive stool culture for C. difficile and received five days of metronidazole. Her symptoms resolved.

During a period of 10 weeks around the time of this patient’s hospitalization, there were six additional cases of C. difficile-associated diarrhea.

Then, a full 12 months later, she was readmitted with tenderness over the suture line. At surgery there was a large abscess associated with the plate that was removed. C. difficile was isolated from the culture. The patient had no enteric symptoms or signs. She was treated with metronidazole.

Pulse field gel electrophoresis (PFGE) analyses of the patient’s fecal and hip isolate were identical showing three large bands, a single band, a middle-sized band, and five smaller bands. Strains from other epidemiologically related strains around the time of the patient’s first admission had dissimilar banding patterns, suggesting real genetic diversity among strains resident at Freemantle Hospital.

Comment by Joseph F. John, MD

The Freemantle doctor is a cooler wind from the west that cools hot summer days in Western Australia. This patient probably wondered what blew into her hip months after it had been plated with steel.

This case of hip hardware infection extends the "spectrum of extraintestinal infection" caused by C. difficile. Fortuitous for this case was collection of the first diarrheal strain that eventually was matched to the isolate causing the hip hardware infection. With sensitive molecular methods, we should expect to see case reports nailing down the genetic identity of the causative pathogens. In an earlier literature review of 18 cases of extraintestinal disease prompted by a case of bacteremia from Robert Wood Johnson Medical School—my resident institution—there were only two cases of osteomyelitis. The current paper sites two more cases of osteomyelitis. Details are not provided for the lag time between the enteric infection and the metastatic infection.

Thus, in this case, we have good documentation of a novel infection with C. difficile of orthopedic hardware a year after its placement and the patient’s enteric infection. PFGE is a tedious but well-proven way to fingerprint isolates of C. difficile and it was used to perfection in this case to show the patient had disseminated infection with an enteric strain that ultimately caused the orthopedic infection. There is some surprise to find such genetic diversity in the other hospital strains analyzed since our working concept of C. difficile infection in the hospital rests on earlier observations that most pathogenic nosocomial strains are related. Here they clearly were not.

C. difficile is a multiresistant pathogen that may emerge as more problematic if metronidazole, or even vancomycin, resistance supervenes. Extraintestinal infection adds the final wrinkle to the pathogenetic scheme of C. difficile.

Which is not a characteristic of extraintestinal infection with C. difficile?

a. It may involve bone and bone structures.

b. It may be preceded by antibiotic-associated colitis.

c. It does not involve the same strains that produce the colitis.

d. Metronidazole remains an effective therapy.