[Antimicrobial resistance of clinical isolates of Stenotrophomonas maltophilia].
OBJECTIVE
To investigate the antimicrobial resistance of clinical isolates of Stenotrophomonas matophilia (SMA) and the mechanisms of their drug resistance.


METHODS
Disc diffusion method (NCCLS) was used to detect the resistant patterns of 88 initial SMA isolates resistant to 12 antibiotics isolated from a local hospital in the past 4 years. PCR was used to detect the 7 aminoglycosides modifying enzymes genes (AME) against amikacin and gentamicin. Metal-beta-lactamases (MBLs) were screened by synergic method, and extended-spectrum beta-lactamases (ESBLs) were detected by double-disk synergy test.


RESULTS
The resistance rates of the SMA isolates were 0%-9.7% to minocycline, 12.5%-22.6% to ticarcillin-clavulanic acid, 12.5%-28.6% to levofloxacin, 18.8%-33.3% to doxycycline, 18.8%-40% to sulfamethoxazole compound, 50%-65.7% to ciprofloxacin, 50%-66.7% to cehazindme, 54.8%-66.7% to amikacin, 75%-100% to gentamicin, 81.3%-100% to piperacillin, 87.5%-100% to aztreonam and 93.5%-100% to imipenem. Aac(3)-I and ant(4')-II were not detected in these strains. The positive rates of the other 5 AME genes of aac(3)-II, ant(2'')-I, aac(6')-I, aac(3)-III, aac(3)-IV were 2.3%, 5.7%, 8%, 10%, and 10%, respectively. SMA strains producing ESBLs were found at the rate of 38.6%; 25% of the strains were MBL-producing, and 13.6% produced both ESBLs and MBLs.


CONCLUSIONS
Most of the SMAs we isolated are multidrug-resistant through various mechanisms. The choice of antibiotics should be made according to the susceptibility results.
Hu
Zu-qiong
ZQ
Department of Epidemiology, School of Public Health and Tropical Medicine, Southern Medical University, and Clinical Laboratory, Guangzhou First People's Hospital, Guangzhou 510515, China.
Yang
Yin-mei
YM
Ke
Xue-mei
XM
Ren
Xu-qi
XQ
Zhou
Wen
W
Chen
Qing
Q
Hu
Jing
J
Yu
Shou-yi
SY
D000583:Amikacin / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D005839:Gentamicins / Q000494:pharmacology*; D006801:Humans; D015378:Imipenem / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D020615:Stenotrophomonas maltophilia / Q000187:drug effects* / Q000302:isolation & purification
D005839:Gentamicins; D015378:Imipenem; D000583:Amikacin