Vol.64 No.1 January 2016
Survey of the combination antimicrobial effect against clinical isolated resistant Pseudomonas aeruginosa using the break-point checkerboard plate method
1)Department of Pharmacy, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, Japan
2)Department of Central Clinical Laboratories, Mie University Hospital
3)Department of Patient Safety and Infection Control, Mie University Hospital
Abstract
Combination antimicrobial therapy has been required to treat resistant Pseudomonas aeruginosa infection in critically ill patients. However, the efficient antimicrobial combination for Pseudomonas aeruginosa remains controversial. In the present study, the antimicrobial combination effect on the clinically isolated Pseudomonas aeruginosa, which has resistance two or more drugs [Imipenem (IPM), Ciprofloxacin (CPFX) and Amikacin (AMK)] from April 2009 to December 2014 in Mie University Hospital was investigated. Multi-drug resistant Pseudomonas aeruginosa (MDRP) was defined as having resistance to all drugs from IPM, CPFX and AMK. Pre-MDRP was defined as having resistance to 2 drugs from IPM, CPFX and AMK. Scoring analysis was used to evaluate the results of the antimicrobial combination effect with the Break-point Checkerboard (BC) plate method. The analysis was challenged again when the skip phenomenon was observed. Sixteen pre-MDRP strains and 10 MDRP strains were extracted. In the pre-MDRP strains, the combination of colistin (CL) and rifampicin (RFP) was most effective (92%; total score 33/perfect score 36) and a combination effect was observed in 8 of 9 strains. In addition, the combination of piperacillin (PIPC) and AMK was the second most effective (90%; total score 18/perfect score 20) and a combination effect was observed in 5 of 5 strains. On the other hand, the combination of CL and RFP was most effective for MDRP (85%; total score 17/perfect score 20) and the combination effect was observed in 4 of 5 strains. In conclusion, the combination of CL and RFP would be considered as one of the useful options for the empiric treatment of resistant Pseudomonas aeruginosa infection.
Key word
break-point checkerboard plate, multidrug-resistant Pseudomonas aeruginosa
Received
July 31, 2015
Accepted
October 16, 2015
Jpn. J. Chemother. 64 (1): 82-86, 2016
