Prevalence of multidrug-resistant organisms recovered at a military burn center
Edward F Keen1, Brian J Robinson, Duane R Hospenthal
1San Antonio Military Medical Center, Brooke Army Medical Center, 3851 Roger Brooke Drive, Fort Sam Houston, TX 78234, USA.
Abstract:
Infections caused by multidrug-resistant (MDR) pathogens are associated with significant morbidity and mortality in patients with burn injuries. We performed a 6-year antibiotic susceptibility records review from January 2003 to December 2008 to assess the prevalence of MDR isolates by pathogen at the US Army Institute of Surgical Research Burn Center. During the study period Acinetobacter baumannii (780 isolates [22%]) was the most prevalent organism recovered, followed by Pseudomonas aeruginosa (703 isolates [20%]), Klebsiella pneumoniae (695 isolates [20%]), and Staphylococcus aureus (469 isolates [13%]). MDR prevalence rates among these isolates were A. baumannii 53%, methicillin-resistant S. aureus (MRSA) 34%, K. pneumoniae 17% and P. aeruginosa 15%. Two isolates, 1 A. baumannii and 1 P. aeruginosa, were identified as resistant to all 4 classes of antibiotics tested plus colistin. A. baumannii isolates recovered from patients with burns greater than 30% of total body surface area (TBSA) were more likely to be MDR (61%) with no significant difference for P. aeruginosa and K. pneumoniae. A higher proportion of MDR P. aeruginosa isolates were recovered from respiratory specimens compared to blood specimens (24% vs. 9%) while the opposite was true for MRSA (35% vs. 54%). A comparison of A. baumannii recovered during hospitalization days 1-5 and 15-30 revealed higher MDR levels as length of stay increased (48% vs. 75%) while no significant trends were observed for P. aeruginosa and K. pneumoniae. A similar pattern was observed for MDR A. baumannii levels for the facility between 2003 and 2005 and 2006-2008 (39% vs. 70%), with no significant increase in MDR P. aeruginosa and MDR K. pneumoniae. Increasing antibiotic resistance patterns of the most prevalent isolates recovered during extended hospitalization, impact of % TBSA and other clinical parameters may affect empirical antimicrobial therapy and patient management decisions during treatment.
Insights
Multidrug-resistant infections in burn patients are a major concern. Acinetobacter baumannii showed increasing resistance over time, especially in severe burns and longer hospital stays.
Area of Science:
- Infectious Diseases
- Clinical Microbiology
- Burn Care
Background:
- Burn injuries are susceptible to infections, often by multidrug-resistant (MDR) pathogens.
- MDR infections significantly increase morbidity and mortality in burn patients.
- Understanding pathogen prevalence and resistance patterns is crucial for effective treatment.
Purpose of the Study:
- To determine the prevalence of MDR pathogens in burn patients.
- To analyze trends in antibiotic resistance over a 6-year period.
- To identify clinical factors associated with MDR infections in burn care.
Main Methods:
- Retrospective review of antibiotic susceptibility records from January 2003 to December 2008.
- Identification and quantification of bacterial isolates from burn patients.
- Analysis of MDR prevalence by pathogen, specimen type, burn severity (TBSA), and length of stay.
Main Results:
- Acinetobacter baumannii was the most prevalent organism (22%), followed by Pseudomonas aeruginosa (20%) and Klebsiella pneumoniae (20%).
- MDR rates were highest for A. baumannii (53%), MRSA (34%), K. pneumoniae (17%), and P. aeruginosa (15%).
- MDR A. baumannii increased with burn severity (>30% TBSA) and extended hospitalization (1-5 days vs. 15-30 days).
Conclusions:
- Acinetobacter baumannii exhibits increasing multidrug resistance in burn patients, particularly with severe injuries and prolonged hospital stays.
- These evolving resistance patterns necessitate careful consideration for empirical antimicrobial therapy and patient management.
- Continued surveillance of antibiotic resistance is vital for optimizing burn wound care and infection control strategies.
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