Gram negative chronic osteomyelitis

Abstract

Background: To assess the demographic profile, clinical and microbiological characteristics, management and treatment outcome in chronic osteomyelitis caused by gram negative organisms. Methods and materials: A chart review of inpatients admitted with chronic osteomyelitis due to gram negative organisms was done over one year from August 2017 to August 2018 in a tertiary care centre in Mumbai. Following data was recorded: demographic profile, clinical presentation, type and site of fracture, intraoperative cultures, management and clinical outcomes. Results: The study cohort comprised of 23 patients [14(61%) males]. Mean age was 54 years (range, 21–83 years). Most common site of fracture was tibia [n = 8 (34%)]. Most common clinical presentation was discharging sinus/wound [n = 20(86%)]. The mean duration of symptoms was 6 months (range, 6weeks–2years). A total of 25 gram negative organisms were isolated from 23 intraoperative samples. 12/25(48%) of these organisms were multi-drug resistant [4/12(33%) were carbapenem resistant and 8/12(66%) were extended spectrum beta-lactamase resistant]. 3/23 (13%) patients had simultaneous Staphylococcus aureus infection. 20/23 (86%) underwent combined surgical and medical management, [9/20(45%) surgical debridement (no implants), 6/20(30%) implant removal and debridement, 3/20(15%) implant retention and debridement, 2/20(10%) underwent amputation]. 3/23(14%) were treated with only antibiotics. Antibiotic impregnated beads were inserted in 8/23 patients. 18/23 (78%) patients had good clinical outcome and 5/23(22%) required repeated debridement (2 had implant retention, 2 had carbapenem resistant organism). Conclusion: Gram negative orthopaedic infections with resistant organisms are especially difficult to manage due to limited antibiotic options, poor penetration at the site of infection, need for prolonged duration of treatment and repeated surgical interventions. Synergistic combination of susceptible antibiotics with extensive debridement and antibiotic impregnated cement/beads at the local site may yield good results.