OBJECTIVETo study the distribution characteristics of pathogens, the drug resistance of Pseudomonas aeruginosa (PA), and the use of antibiotics against Gram negative bacilli (GNB) in burn wards, so as to provide a guide for future treatment.

METHODSA total of 2 758 strains of pathogens were isolated from specimens of wound excretion, venous catheter attachment, blood, stool, urine, and sputum from 7 441 patients hospitalized in our burn wards from January 2007 to December 2012. After being identified by API strips and automatic microorganism identification and drug sensitivity analyzer, drug resistance of all the pathogens to 13 antibiotics commonly used in clinic, including amikacin, cefoperazone/sulbactam, ceftazidime, etc., was tested by K-B paper disk diffusion method. The defined daily doses per 1 000 patient-day of 5 antibiotics including amikacin, cefoperazone/sulbactam, ceftazidime, imipenem, and ciprofloxacin each year was set as use intensity. The WHONET 5.6 software was used to analyze the distribution of pathogens and the drug resistance of PA to 13 antibiotics. The SPSS 19.0 software was used to analyze the relation between changes in drug-resistant rates of PA to 13 antibiotics and year, the relation between the proportion of PA in all the pathogens and the use intensity of 5 antibiotics commonly used against GNB, and the relation between the use intensity of ciprofloxacin and the change in drug-resistant rates of PA to amikacin, cefoperazone/sulbactam, and imipenem with Pearson correlation analysis.

RESULTS(1) In 6 years, Staphylococcus aureus ranked the first with the highest proportion (31%, 865/2 758). The proportion of PA increased to tie in with Acinetobacter baumannii (both accounting for 17%, 458/2 758), both taking the second place. (2) Drug-resistant rates of PA to amikacin, gentamicin, aztreonam, piperacillin, cefoperazone, cefepime, piperacillin/tazobactam, cefoperazone/sulbactam, imipenem, and meropenem were significantly increased and positively correlated with year (with r values from 0.844 to 0.988, P < 0.05 or P < 0.01), while the drug-resistant rate of PA to ciprofloxacin was decreased and negatively correlated with year (r = -0.836, P < 0.05). (3) In 6 years, the use intensity of amikacin (from 8.65 to 91.44), cefoperazone/sulbactam (from 9.62 to 63.56), imipenem (from 7.63 to 157.25), ceftazidime (from 18.39 to 86.11), and ciprofloxacin (from 0 to 19.77) was increased. (4) The proportion of PA in all the pathogens was positively correlated with the use intensity of imipenem and ciprofloxacin (with r values respectively 0.849, 0.933, P < 0.05 or P < 0.01), while it was not significantly correlated with the use intensity of amikacin, cefoperazone/sulbactam, or ceftazidime (with r values respectively 0.672, 0.668, 0.794, P values all above 0.05). (5) The use intensity of ciprofloxacin was positively correlated with the drug-resistant rates of PA to amikacin, cefoperazone/sulbactam, and imipenem (with r values respectively 0.878, 0.934, 0.928, P < 0.05 or P < 0.01).

CONCLUSIONSIn our burn wards, drug-resistant PA was prevalent, with positive correlation with the use intensity of antibiotics. The sensitive rate can be increased by a decrease in the use of amikacin, cefoperazone/sulbactam, and imipenem periodically.