Abstract
Aims
To identify the most common infecting organisms associated with deep infection and infected non-union of the tibia, as well as the rate of ‘culture-negative’ infections, at a tertiary referral trauma centre dealing with military and civilian trauma.
Method
Between 2008 and 2010 all patients with a confirmed clinical diagnosis of implant-related infection or infected non-union of the tibia were identified retrospectively from a database and their records analysed. After a period of at least 10–14 days without antibiotics, all patients underwent surgical debridement in which ‘clean’ samples were went for microbiological analysis. Skeletal stablity was achieved with a circular frame and intravenous antibiotics were started pending culture and sensitivity results.
Results
There were 31 patients; 28 male, 3 female. Mean age 41yrs. 21 patients (68%) had sustained open fractures. In 11 patients, tissue cultures were negative. In the remainder, 8 patients cultured one organism, 6 two organisms, 2 three organisms, and 2 four organisms. Only those with open fractures grew more than 2 organisms. A total of 15 different infecting organisms (all of which were bacteria) were identified. The most common organisms isolated were Staphylococcus aureus, coagulase-negative Staphylococcus, Bacillus and Enterobacter cloacae. There were 3 cases of MRSA infection, all in open fractures. The most frequently used antibiotics for definitive therapy were ciprofloxacin, rifampicin and vancomycin.
Conclusions
The majority of patients had sustained open fractures. Patient with open fractures were more likely to have polymicrobial infections. There was a high rate of culture-negative infections, particularly in the closed fracture group. Meticulous sampling and processing of microbiology samples is essential to minimise the number of culture-negative infections. Laboratory techniques such as polymerase chain reaction may help improve culture yields.
