Septic arthritis in a native joint is most commonly caused by
Staphylococcus aureus, whereas coagulase-negative staphylococcal,
streptococcal, and gram-negative organisms are common infections involving
joints with
prostheses1-3.
Streptococcus pneumoniae is an uncommon cause of infection in a total
knee joint, and pneumococcal infections resistant to multiple antibiotics are
encountered even more rarely. In one study of 3210 total hip replacements,
none of the forty-two documented infections were secondary to
Streptococcus
pneumoniae4.
Poss et al. reviewed the records on 4240 hip, knee, and elbow replacements
performed over a ten-year period and found that only one of fifty-three
infections was due to Streptococcus
pneumoniae5.
In reviewing the literature, we were able to find only four case reports
involving penicillin-resistant pneumococcal septic arthritis in adults and
only one case involving both penicillin and ceftriaxone-resistant
Streptococcus pneumoniae in septic arthritis.
We describe our management of a patient who was found to have a
multidrug-resistant pneumococcal infection in the prosthetic knee joint, and
we discuss the treatment strategies for this emerging pathogen. Our patient
was informed that data concerning the case would be submitted for
publication.
Aseventy-three-year-old man with a history of chronic sinusitis and
degenerative joint disease in both knees had progressive difficulty in walking
secondary to pain in the right knee. In December 2000, he underwent a right
total knee arthroplasty. There were no postoperative complications, and he was
able to walk comfortably after rehabilitation.
In March 2001, he returned to the hospital with a sudden onset of pain,
swelling, and an inability to bear weight on the right knee. He denied having
a fever, cough, rash, sputum production, or any other complaints. Aspiration
of the right knee demonstrated synovial fluid that was grossly purulent. Blood
cultures were negative. Radiographs of the knee showed a joint effusion but
without loosening of the implant. Arthroscopic débridement and
irrigation of the knee was performed the following day without complication.
This treatment was chosen in lieu of open débridement as the infection
appeared localized, and there was no apparent soft-tissue involvement or
systemic signs of infection. No chronic synovial changes were noted.
The joint aspirate demonstrated Streptococcus pneumoniae resistant
to penicillin and ceftriaxone. The Streptococcus pneumoniae was
analyzed for antibiotic sensitivity to vancomycin, which had a minimum
inhibitory concentration of 0.25 µg/mL and a minimum bactericidal
concentration of 0.25 µg/mL. Levofloxacin had a minimum inhibitory
concentration of 0.5 µg/mL and a minimum bactericidal concentration of 1.0
µg/mL. The patient remained in the hospital on a rehabilitation floor for
eight weeks, during which time he was managed with intravenous administration
of vancomycin (1 g every twelve hours) and oral administration of levofloxacin
(500 mg every day). The patient was discharged in good condition in April
2001.
Upon discharge, the antibiotic regimen was changed to oral administration
of levofloxacin (500 mg per day) and rifampin (300 mg twice per day), until
peripheral neuropathy, myalgias, and sleep disturbance developed in July 2001.
These symptoms were attributed to the rifampin, and the antibiotic regimen was
changed to oral administration of a single agent, azithromycin (1200 mg per
week). The adverse effects consequently resolved within a month.
In August 2002, the patient underwent a left total knee arthroplasty for
the treatment of degenerative joint disease. A preoperative aspiration of the
left knee demonstrated no bacteria, and he was placed on prophylactic
intravenous administration of vancomycin (1 g every twelve hours) and rifampin
(300 mg twice a day). There were no complications, and he was discharged on
lifelong treatment with azithromycin.
The patient continued to be followed in both the orthopaedic clinic and the
infectious disease clinic nearly every three months after the last
hospitalization. He remained on oral administration of azithromycin, continued
to walk well, and had had no further episodes of septic arthritis at the time
of the last follow-up. Radiographs of the right knee made in August 2002 and
May 2003 showed no evidence of joint effusion or prosthetic loosening.
Note: The authors thank Daniel Musher, MD, Baylor College of
Medicine, for his assistance.