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Hisham A. Abbas ¹, Fathy M. Serry ¹, Eman M. EL-Masry ¹

Affiliations
1 Department of Microbiology and Immunology-Faculty of Pharmacy-Zagazig University- Zagazig, EG

Abstract

Biofilms are highly resistant to antimicrobial agents. As a consequence, biofilm-based infections are recalcitrant and their treatment is very difficult. Many factors contribute to the biofilm resistance to antimicrobials. The mechanisms of resistance include delayed diffusion of antibiotics through the biofilm matrix, low oxygen and nutrient, reduced growth rates and metabolism. Other resistance mechanisms involved are biofilm-specific phenotypic variants, stress response activation, over expression of efflux pumps, formation of persisters and quorum sensing.

Keywords

Biofilm, Antimicrobial Resistance, Biofilm Matrix, Quorum Sensing, Persister Cells, Phenotypic Variants, Efflux Pumps

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Hisham A. Abbas ¹, Fathy M. Serry ¹, Eman M. EL-Masry ¹

Affiliations
1 Department of Microbiology and Immunology, Zagazig University, Zagazig, EG

Abstract

This study was performed to detect biofilm formation by Pseudomonas aeruginosa by qualitative and quantitative methods. Pseudomonas aeruginosa isolates were tested for their ability to form biofilm by the tube method, the spectrophotometric and the viable count methods. Sixteen isolates (69.6%) were strong biofilm forming; two isolates (8.7%) were moderate biofilm forming, while five isolates (21.7%) were weak biofilm forming by both the tube and spectrophotometric methods. On the other hand, the viable count method was poorly correlated with either of the tube and spectrophotometric methods. High viable counts were recorded for biofilms formed by thirteen isolates (56.5%), one of which was moderate biofilm forming by the spectrophotometric method. Intermediate viable counts were found for biofilms formed by seven isolates (30.4%) including three strong biofilm forming isolates by the tube method, four strong biofilm forming isolates by the spectrophotometric method and two moderate biofilm forming isolates by both the spectrophotometric and the tube methods. This discrepancy of results may be attributed to the fact that, the matrix material and dead cells, in addition to the viable cells, are measured by the tube and spectrophotometric method, while the viable count method detects only viable cells within the biofilm.

Keywords

Biofilm, Pseudomonas Aeruginosa, Biofilm Assessment, Tube, Spectrophotometric, Viable Count.

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Hisham A. Abbas ¹, Fathy M. Serry ¹, Eman M. EL-Masry ¹

Affiliations
1 Department of Microbiology and Immunology, Zagazig University, Zagazig, EG

Abstract

Ten potential antibiofilm agents (N-acetylcysteine (NAC), ambroxol, piroxicam, diclofenac sodium, ketoprofen, 4- nitropyrdidine-N-oxide (4NPO), sodium ascorbate, sucralose, xylitol and sorbitol) showed varied activity against preformed biofilms formed by twenty clinical isolates of Pseudomonas aeruginosa as demonstrated by minimum biofilm inhibitory concentration (MBIC). 4NPO was the most active; Diclofenac sodium, ketoprofen, N-acetylcysteine, ambroxol, sodium ascorbate and piroxicam showed moderate activity, while sucralose, xylitol, and sorbitol demonstrated weak activity.

Keywords

Pseudomonas aeruginosa, Biofilm Inhibition, Antibiofilm Agents.

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Hisham A. Abbas ¹, Fathy M. Serry ¹, Eman M. EL-Masry ¹

Affiliations
1 Department of Microbiology and Immunology, Zagazig University, Zagazig, EG

Abstract

Biofilm-associated infections are persistent and difficult to treat due to the multifactorial antimicrobial resistance. Sugar alcohols have a significant inhibitory effect on dental biofilms. They can reduce the amount of dental plaque and the extracellular polysaccharide (glucans) and intracellular matrix production. The interference with the production of glucans could decrease the extracellular matrix component of mixed oral biofilms.

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