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Interdisciplinary Perspectives on Infectious Diseases
Volume 2009, Article ID 984934, 5 pages
Research Article

In Vitro Synergy of Levofloxacin Plus Piperacillin/Tazobactam against Pseudomonas aeruginosa

1Ochsner Clinic Foundation, 1514 Jefferson Highway, New Orleans, LA 70121, USA
2Premier Infectious Disease Care, 320 Edinburgh Dr., Winter Park, FL 32792, USA

Received 1 June 2009; Revised 30 August 2009; Accepted 9 September 2009

Academic Editor: Melinda Pettigrew

Copyright © 2009 Vladimir Chachanidze et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In vitro synergy testing using levofloxacin (LVX) plus piperacillin/tazobactam (TZP) was performed by Etest and time-kill assay (TKA) for 31 unique fluoroquinolone-resistant Pseudomonas aeruginosa isolates. The Etest method showed synergy for 9/31 (29%) of isolates, while TKA showed synergy with 14/31 (45%) of isolates. When comparing the Etest method and TKA, concordant results for synergy, antagonism, and indifference were obtained for 24/31 (77%) of the isolates tested.