Bactericidal Activity of Various Antibiotics versus Tetracycline-loaded Chitosan Microspheres against Pseudomonas aeruginosa Biofilms

Hanaa A Mahmoud,Nahla A Melake

doi:10.4172/2153-2435.s15-007

Abstract

The discovery of biofilms in 1980’s has brought much interest to the study of the contribution of bacterial biofilms with many recurrent and chronic infectious diseases. In this study, we evaluated the utility of chitosan microspheres in delivering antibiotic in dosage form that could be effective against Pseudomonas aeruginosa (P. aeruginosa) biofilms. P. aeruginosa isolates were collected and identified using standard methods. A modified microtiter plate test was used to determine the biofilm-forming capacity of the isolates. Moreover, bactericidal activity of various antibiotics vs. tetracycline-loaded chitosan microspheres against P. aeruginosa sessile and planktonic cells was tested. Results showed that, most P. aeruginosa strains (92.9%) were efficient biofilm producer-strains. There were differences in the antibiotic susceptibility of planktonic and sessile cell populations. Fluoroquinolones, aminoglycoside and tetracycline showed more potent activity (MIC50 was 0.8, 4.88 and 34.19 μg/ml, respectively) than penicillin, cephalosporin, clarithromycin and macrolides. Biofilm growth was inhibited after 3 h treatment with 2x and 4x MICs and after 24 h treatment with MIC of tetracycline-loaded chitosan microspheres prepared by coacervation method than that prepared by water in oil emulsion method. This was correlated to the cumulative amount of tetracycline that was released from tetracycline-loaded chitosan microspheres prepared by coacervation method which released about 60% of tetracycline in the first 6 h and continued for 24 h. This in the clinical field may be translated into maintaining constant drug concentration for a prolonged period and maximize the therapeutic effect of antibiotics while minimizing antibiotic resistance and improved patient compliance. So, the use of tetracycline-chitosan microspheres may be a new strategy for the development of a specific drug delivery system to increase the efficacy of tetracycline against biofilm-associated P. aeruginosa infections. However, it would be appropriate to conduct clinical studies to confirm this.

Highlights

Fourth, living after accepting death addresses the fundamental change in priorities and motivation for daily tasks once an individual has confronted and accepted their own death or the death of others and survived. While this re-prioritization can be beneficial in that individuals may be less likely to worry about minutiae or comparatively minor stressors, it can create problems when readjusting to civilian life as a Veteran may experience apathy and exhibit a failure to respond to expectations of others in social and vocational settings because they are deemed to be unimportant
To evaluate whether attendees’ understanding of Veterans’ reintegration experiences improved as a function of attending an overview of the Faber Post-Trauma Model (FPTM), t-tests were conducted for each item to evaluate self-reported change from baseline to post-presentation
There were no significant differences between military and non-military personnel in terms of their reported change in understanding as a result of this intervention (Cohen’s d = 1.01 and 1.06, respectively). These findings demonstrate that Veterans, friends and significant others, and community members came away from the presentations with an enhanced understanding of common difficulties that Veterans encounter when reconnecting with civilian life after combat

Summary

Participants

Using 5-point Likert-type scaling, the measure inquired about respondents’ knowledge of Veterans’ emotional functioning, psychological functioning, social functioning, relationship with significant others, post-combat changes in life priorities, difficulties with future orientation and planning, mental health needs, suicidality, available mental health approaches, and likelihood of getting treatment if needed of assisting Veterans in accessing services. These domains reflected the core content of the Faber Post-Trauma Model designed to convey information about Veterans’ reintegration and post-combat adjustment.

Procedure

Results

Discussion