OBJECTIVETo evaluate the in vitro antimicrobial activity of piperacillin-sulbactam against clinical isolates of non-fermentative bacilli isolated from common infections.METHODSMicrodilution was employed to study the antimicrobial resistance.RESULTSA total of 770 strains were collected from 6 hospitals in Guangzhou, including Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia, Burkholderia cepacia, Flavobacterium, and Alcaligenes. Compared with other β-lactams, piperacillin-sulbactam displayed the highest activity against all the isolates of P.aeruginosa, especially for imipenem non-sensitive isolates, with the susceptibility of 71.9% and 55.8%, respectively. Piperacillin-sulbactam and cefoperazone-sulbactam kept good activity against imipenem sensitive isolates of A.baumannii, with the susceptibility of 71.0% and 73.0%, respectively. For the strains of Burkholderia cepacia, 69% strains exhibited minimal inhibitory concentration (MIC) of ≤ 16 mg/L for piperacillin-sulbactam. For the strains of Flavobacterium, and Alcaligenes, piperacillin-sulbactam also had excellent activity, with the susceptibility of 70.2% and 94.4%, respectively.CONCLUSIONPiperacillin-sulbactam exhibits good activity again non-fermentative bacilli, especially for imipenem non-sensitive isolates of P.aeruginosa.