Assessment of combination therapy by time kill curve analysis and chequerboard assay for treatment of multi-drug resistant Pseudomonas aeruginosa isolates

Meher Rizvi*, Junaid Ahmed, Fatima Khan, Indu Shukla, Abida Malik

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Multidrug resistant Pseudomonas aeruginosa is a major nosocomial pathogen, and effective therapy presents a great clinical challenge. Combination therapy, employing pre-existing antibiotics, is an attractive approach for the treatment of such infections which may also curtail drug resistance. This study was undertaken with the objectives to assess the synergy of five different antimicrobial combinations (piperacillin-tazobactum with levofloxacin, cefoperazone-sulbactum with levofloxacin, piperacillin-tazobactum with amikacin, cefoperazone-sulbactum with amikacin and amikacin with levofloxacin for the treatment of Pseudomonas aeruginosa isolates with varied susceptibility profile by time kill curve assay and the chequerboard technique. In our study concordance between these two methods was noted in 71.7% isolates tested. Le-Pt combination demonstrated maximum synergy (72.7%), followed by Ak-Le (66.7%) and Ak-Cfs (60%) combination. Le-Cfs and Ak-Pt however, showed synergy in significantly lower number of isolates. However, at sub-MIC concentrations Ak-Pt combination was found to be most effective. Synergy between different drugs should be routinely monitored for exploring more feasible treatment options and to prevent the emergence of multi-drug resistant strains. Piperacillin- tazobactum emerged as a versatile drug whose potential should be explored with other drugs for combination treatment of P. aeruginosa isolates.

Original languageEnglish
Pages (from-to)103-108
Number of pages6
JournalJournal of Global Antimicrobial Resistance
Issue number2
Publication statusPublished - Jun 2013
Externally publishedYes


  • Chequerboard
  • Combination therapy
  • Multidrug resistance
  • Synergy
  • Time kill

ASJC Scopus subject areas

  • Microbiology
  • Immunology and Allergy
  • Immunology
  • Microbiology (medical)

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