89 Antimicrobial Resistance Pattern and Prevalence of Extended Spectrum Beta-lactamase in Non-fermenting Gram Negative Bacteria, Isolated from Burn Wounds: A Prospective Study from a Tertiary Burn Center

Introduction Burn wound infections are one of the major causes for long-term hospitalization and mortality among patients with thermal injuries. Identifying the bacterial cause of infection and determining the appropriate antibiotic to treat these infections is an important stage in treatment. The aim of this study was to investigate antimicrobial drug resistance in non-fermenting gram-negative bacteria isolated from burn wounds in patients who were admitted to a tertiary burn center. Methods In this prospective study during a six-month period in 2018,100 isolates of non-fermenting gram-negative bacteria were collected from 100 patients with thermal injuries. Antibiotic susceptibility test was performed using the Kirby-Bauer method based on the clinical and laboratory standards institute guidelines. Double-disc synergy test, a phenotypic method, was used to identify strains producing extended-spectrum beta-lactamase (ESBL). Data analyses were performed using SPSS. Results A total of 100 wound samples were examined from 100 patients, 76% were male and 24% were female with a mean age of 33 years (range 1–89 years old). Mean total body surface area burned was 35% (range 1–95%) and mean length of hospital stay was 24 days (range 3–69 days). Eighty five percent of cases were under 50 years old. Overall mortality rate in this study was 17%. The major causes of burn were liquefied natural gas tank explosion (35%) and scalds (19%). Acinetobacter baumannii (A.baumannii) was the most common pathogen followed by Pseudomonas aeruginosa (P.aeruginosa) (60% and 40%, respectively). ESBL producing rate was significantly higher in P.aeruginosa isolates (27.5%) than A.baumannii isolates (3.3%) (P-value < 0.001). Antibiotic resistance pattern of P.aeruginosa showed the highest resistance to ciprofloxacin, amikacin and imipenem (95%), followed by gentamicin (92.9%),ceftazidime(87.50) and piperacillin-tazobactam(85%). Antibiotic resistance pattern of A.baumannii showed the highest resistance to ceftazidime(100%) followed by ciprofloxacin, amikacin, imipenem(98.3%), gentamicin and piperacillin-tazobactam (93.3%). Multiple drug resistance (MDR) rate among A.baumannii and P.aeruginosa was 98.3% and 92.5% respectively, which is higher than previous reports. Conclusions A.baumannii and P.aeruginosa were the most common pathogens identified in this cohort with a significant MDR rate (over 95%). New strategies to control expansion of antimicrobial resistance in burn centers are necessary. Applicability of Research to Practice This study shows the antimicrobial resistance pattern and prevalence of ESBL in burn wounds indicating that further studies requires to identify new strategies to control emerging antimicrobial resistance in burn centers.