Effect of Tobracef on biofilms of aminoglycoside resistant Pseudomonas aeruginosa

Abstract

The present study was undertaken with the aim to find prevalence of biofilm forming ability among Pseudomonas aeruginosa clinical isolates. A total of 129 clinical isolates were identified from clinical specimens by standard microbiological techniques. Biofilm formation ability among these isolates was studied using in vitro bifilm formation assay. Minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) were studied using procedure as described in Clinical and Laboratory Standards Institute. Among 129 isolates, the prevalence of aminoglycoside resistance was 75.2 % out of which 70.1% were found to be biofilm producers. The MIC for Tobracef in aminoglycoside resistant strains ranged from 8 to 16 μg/ml and for other antibacterial drugs it ranged from 16 to 256 μg/ml. The MBEC for Tobracef in biofilm producing isolates was ranged from 32 to 64 μg/ml and for other antibacterial agents, it ranged from 1024 to 8292 μg/ml. When the effect of half of MBEC of drugs were evaluated on preformed biofilms, Tobracef significantly reduced viable counts of bacterial cells presented in biofilms of P. aeruginosa with log reduction values ranging 5.17 to 5.46 logs. Our data showed that Tobracef has significantlly enhanced activity against aminoglycoside resistance biofilm producing isolates. Therefore, use of this antibiotic should be considered to treat the infections caused by aminoglycoside resistant biofilm producing isolates.