medwireNews: The high risk for infection in patients with extensive soft tissue damage around an open fracture is not reduced by extending the duration of antibiotic treatment, research suggests.
Patients with grade III Gustilo and Anderson open fractures - denoting extensive tissue laceration, damage or loss - were a significant 12.5 times more likely to develop infection than patients with Grade I fractures, after adjusting for a raft of confounding factors, report Ilker Uçkay (Geneva University Hospitals, Switzerland) and co-authors.
And patients with grade IIIc open fractures - who sustained arterial damage requiring repair - were 12.5 times more likely to develop infection than patients with grade IIIa fractures.
Moreover, choice or duration of antibiotic treatment did not alter infection risk, with no significant difference between patients who received 1, 2 to 3, 4 to 5, or more than 5 days of prophylaxis.
"Prophylaxis beyond one day does not seem to counterbalance the negative effects of injury when decontamination fails in the early initial management," the team concludes in the Bone & Joint Journal.
Recognizing that antibiotics are not recommended for more than 24 hours in patients with grade I or II fractures, the researchers add: "If confirmed in prospective trials, what is already known for grade I or II fractures could be extended to grade III fractures."
By contrast, the researchers found no evidence to suggest that the risk for infection was influenced by the number of surgical interventions required, delay between trauma and surgery, season, or the patient's immunosuppressive status.
The study reviewed the outcome of 1492 open fractures in 1290 patients who underwent surgery within a day of injury and received a median of 3 days' antibiotic prophylaxis.
Overall, 3.6% of sites became infected at a median of 10 days, including 0.9% of 663 grade I fractures, 1.9% of 370 grade II fractures, and 12.0% of 310 grade III fractures. Among grade III patients, those with subtype IIIc open fractures were significantly more likely to develop infection than those with IIa or IIb damage (33.3 vs 3.2 and 5.7%, respectively).
Of note, 71% of infection sites were colonized by pathogens resistant to the antibiotic regimen given.
"This could be the result of low inoculum present at the site of injury and their different virulence, or the pathogen(s) isolated might have been selected by the prophylactic agent," Uçkay et al observe.
"If we infer that infectious pathogens were indeed selected by the antibiotic regimen or its duration, this would further support the use of a short course therapy to avoid selection."
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