Bacteriological profile and antibiotic resistance of bacteria isolates in a burn department

Introduction

Nosocomial infections remain the main cause of morbidity and mortality in burn patients. Ongoing surveillance of infections in burned patients is essential to detect changes in epidemiology and to guide better empirical antibiotherapy and infection control policies. The aim of this study was to analyze the bacterial flora and the antibiotic resistance of isolates in a burn department during a 2-year period.

Methods

From 1 January 2005 to 31 December 2006, 1,268 strains were isolated from different specimens. Antimicrobial susceptibility testing has been carried out by the disk diffusion method as referred by the French Society of Microbiology. All data were stored in a laboratory database using whonet 5.3 software. Duplicate isolates defined as the same bacterial species for the same patient with the same antimicrobial susceptibility profile were excluded.

Results

The most frequently identified species were Staphylococcus aureus (19.8%), Pseudomonas aeruginosa (15.8%), Acinetobacter baumannii (11.8%), and Providencia stuarttii (9.5%). The rate of methicillin-resistant S. aureus (MRSA) was 68.1%. All isolates were fully susceptible to glycopeptides. P. aeruginosa resistance was 35.6% and 35.4% respectively for ceftazidime and imipenem. Concerning A. baumannii, 98.7% of strains were resistant to ceftazidime, 59.5% to imipenem and 87.5% to ciprofloxacin. In total, 77.3% of P. stuarttii isolates were resistant to ceftazidime. The frequencies of resistance to ceftazidime, ofloxacin and amikacin of Klebsiella pneumoniae were respectively 60.9%, 25.4% and 47.1%. The survey of resistance showed a global decrease in 2006 versus 2005. The rate of MRSA was 61% in 2005 versus 51.6% in 2006. The resistance of ceftazidime was 80.6% in 2005 versus 26.9% in 2006 in P. aeruginosa. The imipenem resistance showed also a decrease in 2006 in A. baumannii and P. aeruginosa. The amelioration of hygiene, particularly washing hands after introduction of hydroalcoholic solutions, and the collaboration between microbiologists and clinicians could explain the decrease of resistance showed in the burn department.

Conclusion

Comparative to the previous years, S. aureus is still the commonest pathogen in the burn department. The incidence of antimicrobial resistance has decreased during 2006 after a peak of multiresistance during 2005. The measures of prevention taken were efficient and should be re-enforced.