[Analysis of distribution characteristics and drug resistance of 2748 strains of pathogens isolated from burn patients].
OBJECTIVE
To provide epidemiological data of the distribution characteristics and drug resistance of the pathogens isolated from burn patients in recent years for guiding rational use of antibiotics in clinic.


METHODS
Totally 2748 strains of pathogens were isolated from 1977 specimens (blood, catheter, wound excretion, etc.) collected from 478 patients hospitalized in Institute of Burn Research of Southwest Hospital from March 2003 to June 2011. After being identified by API strips, drug resistance of the 2748 isolated pathogens to 55 commonly-used antibiotics including gentamicin, tobramycin, piperacillin, amikacin, etc. was tested by K-B paper disk diffusion method. The WHONET 5.3 software was used to analyze the following subjects: the distribution of the pathogens with different types and different sources each year, the changes in drug-resistant rates of Gram negative bacilli, Gram positive cocci, and fungi to several antibiotics, and the changes in sensitive rates of Pseudomonas aeruginosa (PA), Staphylococcus aureus (SA), Acinetobacter baumannii (AB), Candida albicans (CA) to several antibiotics.


RESULTS
Among 2748 strains of pathogens, 1879 strains of Gram negative bacilli accounted for 68.38%, 628 strains of Gram positive cocci accounted for 22.85%, and 241 strains of fungi accounted for 8.77%. The isolation rate of strains from wound excretion ranked the first (1022 strains accounted for 37.19%), followed by those from respiratory tract (995 strains accounted for 36.21%) and blood (421 strains accounted for 15.32%). Strains isolated from other types of specimens were rare. Isolation rate of PA ranked the first (996 strains accounted for 36.24%), followed by SA (495 strains accounted for 18.01%) and AB (395 strains accounted for 14.37%). Isolation rate of AB showed a trend of increase year by year, but that of SA presented the opposite trend. Isolation rate of PA was quite stable. There were 484 strains of methicillin resistant SA among Staphylococci, accounting for 17.61%. Resistant rates of PA and AB to polymyxin B and polymyxin E were below 30.00%, and those of PA and AB to other antibiotics, such as the third generation cephalosporins, β-lactams, aminoglycosides, and quinolones, were from 57.91% to 100.00%. Resistant rate of AB to minocycline was 39.68%. From 2004 to 2011, sensitive rate of PA to quinolone antibiotics showed an increasing trend year by year, but that of AB to minocycline, netilmicin, imipenem, meropenem, tobramycin, and cefoperazone/sulbactam presented the opposite trend. Resistant rates of Enterococcus faecalis, Enterococcus faecium, and SA to teicoplanin and linezolid were less than 10.00%. Resistant rate of SA, Staphylococcus epidermidis and Enterococcus faecium to vancomycin was 0. Resistant rates of SA to quinupristin/dalfopristin, minocycline, fusidic acid, and compound sulfamethoxazole were low, respectively 0.82%, 9.35%, 2.21%, and 31.85%. Sensitive rates of SA to erythromycin, clindamycin, compound sulfamethoxazole, tetracycline, and minocycline showed an increasing trend year by year. Both infection rate and resistant rate of fungi were low. The resistant rates of CA to 5 kinds of antibiotics were less than 15.00%. The sensitive rate of CA to 5-flucytosine declined slightly, and those of CA to the other 4 antibiotics showed an increasing trend year by year.


CONCLUSIONS
The three dominant pathogens that cause infection in burn patients hospitalized in Institute of Burn Research of Southwest Hospital in recent years are PA, SA, and AB in order. PA and AB are outstandingly multidrug-resistant among the isolated strains. AB might replace PA as the main pathogenic bacterium that cause the death of burn patients with infection.
Institute of Burn Research, Southwest Hospital, State Key Laboratory of Trauma, Burns and Combined Injury, the Third Military Medical University, Chongqing 400038, China. dzpengmd@126.com
Dai-zhi
DZ
Peng
Xiao-ling
XL
Liu
Zhi-yong
ZY
Liu
Wen-ting
WT
Shu
Xin
X
Zhou
Jing
J
Liu
Yue-sheng
YS
Huang
Jun
J
Wu
Wei-ling
WL
Fu
D040981:Acinetobacter baumannii / Q000187:drug effects / Q000302:isolation & purification; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002056:Burns / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D003428:Cross Infection / Q000382:microbiology; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000302:isolation & purification; D013211:Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification; D055815:Young Adult
D000900:Anti-Bacterial Agents