Spectrum and drug resistance of pathogens from patients with burns

Microbial infection is an obstacle of burn treatment. However, little is known on what types of microbial infection dominate in the burn center and how the dynamic change of those microorganisms occurs during the past several years in China. We conducted a retrospective study of nosocomial infection (NI) in a large burn center to analyze the spectrum and antimicrobial resistance of microbial isolates from January 2003 to December 2010. We studied 989 isolates from 677 patients who had signs and symptoms of infection 48h after admission. The number of NIs per 100 admissions was 10.9. The commonest isolates were Pseudomonas aeruginosa (23.1%), Staphylococcus aureus (18.7%), and Candida (11.4%). The result indicated that the numbers of patients with Acinetobacter sp. infection increased (P=0.004), but with Proteus mirabilis infection decreased (P=0.004). The isolated Acinetobacter sp. and P. aeruginosa were consistently highly resistant to almost all antibiotics tested. Notably, more frequent Acinetobacter sp. isolates appeared to be resistant to amikacin, gentamicin, tobramycin, ceftazidim, piperacillin, tazobactam, levofloxacin, and ciprofloxacin and more frequent Escherichia coli isolates were resistant to ceftazidime and aztreonam at the late time period although the P. aeruginosa and E. coli isolates were sensitive to less used ciprofloxacin and piperacillin/tazobactam. The increased rates of drug-resistant isolates in the later period might be associated with regular prophylactic therapy with antibiotics.