This study was planned to evaluate the efficacy of silver nitrate and gentamicin in the treatment of burn wound infection and to compare it with phage therapy using an isolated and well-characterized Klebsiella-specific phage, Kpn5. A full-thickness burn wound was induced in mice and infected with Klebsiella pneumoniae B5055 via the topical route. Different concentrations of silver nitrate or gentamicin were applied topically daily after establishment of infection. Phage Kpn5 mixed in hydrogel was also applied topically at an m.o.i. of 200 on the burn wound site. The efficacy of these antimicrobial agents was assessed on the basis of percentage survival of infected mice following treatment. The results showed that a single dose of phage Kpn5 resulted in a significant reduction in mortality (P,0.001). Daily applications of silver nitrate and gentamicin at 0.5 % and 1000 mg l "1 , respectively, provided significant protection (P,0.001) compared to lower concentrations of the two agents. However, the level of protection given by these two agents was lower than that given by the phage therapy. The results strongly suggest that phage Kpn5 has therapeutic utility in treating burn wound infection in mice as a single topical application of this phage was able to rescue mice from infection caused by K. pneumoniae B5055 in comparison to multiple applications of silver nitrate and gentamicin.
INTRODUCTIONMainly because of the larger area involved and longer duration of patient stay in hospital, burns provide a suitable site for bacterial multiplication and are a more persistent, richer source of infection than surgical wounds (Ozumba & Jiburum, 2000;Mayhall, 2003). The risk is further exacerbated by immunosuppression associated with burn injury (Cook, 1998). In addition, the burn surface, which contains a large amount of necrotic tissue and protein-rich wound exudate, provides a rich growth medium (Erol et al., 2004;Taneja et al., 2004) and hence infection remains the principal cause of death in burn patients (Heggers et al., 1991;Pruitt et al., 1998).Third-degree burns, which are the most severe form of burn, usually need dressing with appropriate medication in order to prevent infection (Panjeshahin et al., 2001). Topical antimicrobial agents are essential adjuncts in the prevention and treatment of burn wound infections (Ollstein & McDonald, 1980;Noronha & Almeida, 2000). Several groups of topical medications and antibiotics such as silver nitrate, gentamicin and polymyxin B have been used in the treatment of wound infection of burns (Moyer et al., 1965;Fox, 1968;Snelling et al., 1978;Steen, 1993;Ward & Saffle, 1995). Because systemic antibiotics are ineffective in reducing bacterial counts in granulation wounds, the use of suitable topical antibacterial agents may substantially decrease wound sepsis and benefit overall burn wound management (Manafi et al., 2008).The widespread use of antimicrobial agents in hospital settings has led to the emergence of multidrug-resistant organisms of low virulence such as Klebsiella c...