ISSN: 0973-7510

E-ISSN: 2581-690X

Research Article | Open Access
Dhara Patel, Palash Sen, Yin Hlaing, Michael Boadu,Bassam Saadeh and Paramita Basu
Department of Pharmaceutical and Biomedical Sciences, Touro College of Pharmacy, 230 W 125 Street New York, NY 10027, U.S.A.
J Pure Appl Microbiol. 2021;15(4):2520-2528 | Article Number: 7347 | © The Author(s). 2021
Received: 01/10/2021 | Accepted: 10/11/2021 | Published: 30/11/2021

Pseudomonas aeruginosa (PA) is part of a group of common nosocomial pathogens that exhibit multidrug resistance, thus proving to be a significant threat to healthcare. This study analyzes the ability of four commonly used antibiotics to observe eradication of the PA biofilm growth. Ceftazidime (CAZ), Tobramycin (TOB), Ofloxacin (OFLX), Meropenem (MEM), were tested against overnight cultures of PA strain PA01. The minimal inhibitory concentrations (MIC) of planktonic cells for all the four antibiotics were determined using broth microdilution while the minimal bactericidal concentrations (MBCs) were determined by colony count after antibiotic treatment and regrowth. Biofilm growth inhibition was performed by treating cells with antibiotic at the time of inoculation while eradication was determined by adding antibiotics 24 hours after inoculation, allowing mature biofilm formation, followed by the measurement of absorbance. PA planktonic cells exhibited highest susceptibility to MEM compared to overnight grown PA biofilm which demonstrated resistance to CAZ, complete sensitivity to ofloxacin, and minimal sensitivity to TOB and MEM. PA biofilm displayed dose-dependent sensitivity to TOB, MEM and OFLX, and a significant level of resistance to CAZ during inhibition phase. However, in the eradication phase, PA showed significant resistance to TOB followed by CAZ while PA biofilm showed sensitivity at higher concentrations of MEM. Our study exhibits that PA strain PA01 is resistant to ceftazidime in both planktonic and biofilm phases. While ofloxacin proved to be the most effective even at lower concentrations when compared with other antibiotics, tobramycin was most effective at higher concentrations for eradicating and inhibiting PA biofilms.


Pseudomonas aeruginosa, biofilm, CAZ: ceftazidime, OFLX: ofloxacin, MEM: meropenem, TOB: tobramycin

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© The Author(s) 2021. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License which permits unrestricted use, sharing, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.