Microbiology of bone and joint infections in injecting drug abusers.

Abstract

BACKGROUND:

The literature contains variable reports on the causative organisms of osteomyelitis and septic arthritis in patients with injecting drug abuse and on the rate of oxacillin-resistant S aureus. It is important to have a clear notion of the organisms to initiate empiric antimicrobial therapy.

QUESTIONS/PURPOSES:

We therefore determined the spectrum of organisms in bone and joint infections in patients who were injecting drug users.

METHODS:

We retrospectively reviewed the medical records of 215 patients (154 male, 61 female) with a history of injecting drug abuse and concurrent bone and/or joint infection from 1998 to 2005. The mean age was 43 years (range, 23-83 years). Osteomyelitis was present in 127 of the 215 patients (59%), septic arthritis in 53 (25%), and both in 35 (16%). The lower extremity was most commonly involved (141 cases, 66%), with osteomyelitis of the tibia present in 70 patients (33%) and septic knee arthritis in 30 patients (14%).

RESULTS:

Cultures yielded predominately Gram-positive bacteria: Staphylococcus aureus in 52% and coagulase-negative Staphylococcus in 20%. The proportion of oxacillin-resistant S aureus among S aureus infections increased from 21% in 1998 to 73% in 2005. Gram-negative organisms were present in 19% of infections and anaerobes in 13%. Patients with osteomyelitis had a higher prevalence of polymicrobial infections (46% versus 15%), infections due to Gram-negative organisms (24% versus 9%), and anaerobic infections (19% versus 6%) compared to patients with septic arthritis.

CONCLUSIONS:

These findings suggest broad-spectrum empiric antibiotic therapy, including vancomycin, should be considered for bone and joint infections in patients with injecting drug abuse.

LEVEL OF EVIDENCE:

Level IV, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

• Authors: Daniel C Allison, Paul D Holtom, Michael J Patzakis, Charalampos G Zalavras
• Journal: Clinical orthopaedics and related research (Clin Orthop Relat Res) Vol. 468 Issue 8 Pg. 2107-12 (Aug 2010) ISSN: 1528-1132 [Electronic] United States
• PMID: 20174899 (Publication Type: Journal Article)

Chemical References

• Anti-Bacterial Agents
• Oxacillin

Topics

• Adult
• Aged
• Aged, 80 and over
• Anti-Bacterial Agents (pharmacology)
• Arthritis, Infectious (epidemiology, microbiology)
• California (epidemiology)
• Comorbidity
• Female
• Humans
• Knee Joint (microbiology, pathology)
• Male
• Methicillin Resistance (drug effects)
• Microbial Sensitivity Tests
• Middle Aged
• Osteomyelitis (epidemiology, microbiology)
• Oxacillin (pharmacology)
• Retrospective Studies
• Staphylococcal Infections (epidemiology, microbiology)
• Substance-Related Disorders (epidemiology, microbiology)
• Young Adult