The Effectiveness of Chloramphenicol as Prophylaxis for Wound Infection after Minor Skin Surgery

Surgical site infection is the most common hospital-acquired infection in surgical patients. It is estimated that approximately 5% of patients undergoing surgery develop surgical site infection. This may result in the failure of the wound healing which could increase the cost of treatment, prolong hospital stay, and also increase post-operative mortality. Some surgeons prescribe topical antibiotics as prophylaxis against surgical site infection. One of the most common topical antibiotics used prophylactically post-surgery is chloramphenicol eye ointment. Chloramphenicol has a broad spectrum of activity against Gram positive and Gram negative bacteria, and anaerobes. The ointment is indicated for the treatment of bacterial conjunctivitis with little evidence published to support it as prophylaxis, or treatment, of wound infection. The Therapeutic Guidelines: Antibiotic does not recommend the use of topical antimicrobials prophylactically, with the exception of ophthalmic surgery, burns, or excessive skin loss.

However, a survey in the United Kingdom reported that 66% of plastic surgeons surveyed used chloramphenicol eye ointment as prophylaxis against infection. This is also a common practice among many practitioners in Australia as there has not been a consensus developed on the use of topical chloramphenicol as prophylaxis in minor surgical procedures.

There is some concern regarding the overuse of topical antibiotics, which may result in the development of antibiotic resistance. Australian and British guidelines suggest that the use of topical antibiotics including chloramphenicol ointment should be restricted. This is due to the capacity of most topical drugs to select for resistant microorganisms and also to cause sensitisation. A prospective randomised controlled study was conducted in multiple hospitals in Queensland to determine the effectiveness of topical chloramphenicol as prophylaxis following minor skin surgery. 509 patients were randomised to receive Chloromycetin^® (chloramphenicol) eye ointment 10mg/g and 505 were randomised to the placebo group, which received paraffin ointment. The respective ointments were applied to the sutured wound following surgery. The primary outcome measure was the incidence of infection as evaluated on the day pre-arranged for suture removal. It was determined by the investigators that with a projected infection rate of 10%, a decrease in incidence of infection by 5% would be clinically significant.

The study found that the relative risk reduction was 40% and the absolute risk reduction was 4.4%, which was less than the pre-determined 5% required to be clinically significant. Hence, although the results were statistically significant, the chloramphenicol ointment did not reduce the incidence of infection enough to be clinically significant. The study concluded that chloramphenicol ointment as prophylaxis treatment may not produce a meaningful benefit in settings where infection rate is already low.

To summarise, the use of chloramphenicol in surgical wound infection prophylaxis has not been recommended in Australian or British guidelines due to two major concerns; limited evidence supporting its use, and the theoretical risk of antibiotic resistance. However, Heal, Buettner et al. argued that the potential for antibiotic resistance with topical antibiotics is lower than with systemic antibiotics due to the lower systemic exposure made possible by topical delivery. The author also observed that there is no evidence to support the theoretical risk of antibiotic resistance with the use of topical chloramphenicol. Topical antibiotic ointments have been used extensively worldwide over the last three decades, with research finding no evidence to show that the topical usage (except for mupirocin) contribute to any emerging resistance pattern. Due to the moderate absolute risk reduction in surgical site infection rate and the lack of evidence of antibiotic resistance with the use of topical chloramphenicol, topical chloramphenicol could be recommended after minor skin surgery, but is best reserved for patients at high risk of infection.

At present, the Royal Adelaide Hospital has a restriction policy on antibiotics whereby topical application of antibiotics (including chloramphenicol) to wound and suture lines is not an approved indication. Alternative treatments which may be recommended instead of topical antibiotics include: the administration of an appropriate systemic antibiotic to prevent a wound infection, the topical application of an antiseptic preparation such as povidone-iodine or chlorhexidine cream, and the topical application of sterile paraffin to prevent the drying of suture lines.