The time-related changes of antimicrobial resistance patterns and predominant bacterial profiles of burn wounds and body flora of burned patients

Abstract

To examine the bacterial isolates from the burn patients and to compare the antibiograms of the predominant bacteria isolated from 51 patients who were hospitalized at least 3 weeks or more over a period of 7 months, a prospective study was undertaken. Periodic swabs were taken from burn wound, nasal, axillary, inguinal, and umbilical region of the patients on admission and on 7th, 14th, and 21st days of hospitalization. Mean hospital stay was 36.5 days. A total of 1098 microbial isolates were detected during the study period. Coagulase-negative staphylococci (CNS, 63.0%) and Staphylococcus aureus (19.7%) were the most prevalent isolates in admission cultures. During the next weeks, these bacteria were superceded by mainly Pseudomonas aeruginosa. Between admission and 21st day, the rates of methicillin resistance of staphylococci strains increased steadily. There was no vancomycin resistance in any staphylococci strains, although nine of the S. aureus isolates (2.7%) were resistant to teicoplanin. There were no strains producing inducible beta lactamase (IBL) among P. aeruginosa strains. One extended-spectrum beta-lactamase (ESBL)-producing strain was recovered on admission, although strains producing IBL and ESBL were detected at rates of 79.6 and 57.1%, respectively, on the 21st day. The nature of microbial wound colonization, flora changes, and antimicrobial sensitivity profiles should be taken into consideration in using empirical antimicrobial therapy of burned patients.