Anti-biofilm Activity of Chitosan from Crab and Shrimp Species
Indigenous to the Philippines on Established Biofilms of Pseudomonas
aeruginosa and Staphylococcus aureus
Berley Jane Aurestila, Erla Ann Marie Villaver
*
and Elizabeth Y Tan
Department of Pharmacy, University of San Carlos, Philippines
*
Corresponding author: Erla Ann Marie Villaver, Department of Pharmacy, University of San Carlos, Philippines, Tel: +63-9199886591; E-mail: erlavillaver@yahoo.com
Received date: January 22, 2018; Accepted date: January 29, 2018; Published date: February 01, 2018
Copyright: © 2018 Villaver EAM, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
Biofilms are structures produced by bacteria by attaching themselves together in a surface to form a protective
matrix, rendering them resistant to antimicrobial treatments. The objective of this study was to examine the anti-
biofilm activity of chitosan from crab and shrimp species on the established biofilms of Pseudomonas aeruginosa
and Staphylococcus aureus. The test groups were treated with chitosan solutions of varying concentrations (2.5 g/L
and 10 g/L) chitosan from shrimp shells extract, 2.5 g/L and 10 g/L crab shells extract and a mixture of both shell
extracts with the same concentration mixed in a one-to-one volume by ratio. Three different analysis were conducted
involving color intensity test through TotalLab software, spectrophotometric analysis and microplate reader analysis.
The highest percent anti-biofilm formation inhibition was observed with the 2.5 g/L mixed (1:1) chitosan solution
against established biofilms of P. aeruginosa with a 62.90 ± 12% inhibition. On the other hand, S. aureus showed no
percent inhibition with the 2.5 g/L shrimp chitosan and 10 g/L crab chitosan but was most sensitive to 10 g/L mixed
(1:1) chitosan solution with an inhibition of 39.47 ± 19%. From the results, the 1:1 combination of shrimp and crab
chitosan solutions resulted to a higher percent anti-biofilm formation inhibition than when given separately.
Keywords: Bioflm formers; Chitosan; Crabs; Shrimps
Introduction
According to the World Health Organization (2016), antimicrobial
resistance continues to be a global problem due to wide range of
infections caused by bacteria, virus, fungi or parasites. Microorganisms
develop certain mechanisms to counteract the medical treatments such
as the enzymatic inactivation of the antibiotic or alteration and
modifcation of the antibiotic target site which would render the
antibiotic useless [1]. As a result, patient’s illness would be prolonged
and there would be difculties in curing the acquired infection. Bioflm
formation is one of the mechanisms acquired by microbes to
counterattack the efects of the antibiotics at hand. Bioflms are
structures produced by bacteria by attaching themselves together in a
surface (inert or living) to form a protective matrix. To address this
problem, this study was conducted to combat the microbial bioflms
formed by destroying it permanently. As a result of this, the microbe
will then be exposed and will be susceptible to any antimicrobial agent
which leads to the death of the microbial cell.
Not all microorganisms are capable of forming bioflms.
Pseudomonas aeruginosa, a Gram-negative bacterium, is known to be
resistant to antibiotic treatments due to formation of bioflms. Tis
opportunistic pathogenic bacterium is known to be responsible for
various infections, particularly in immunocompromised patients [1].
Another bacterium capable of bioflm formation is the Staphylococcus
aureus. S. aureus is considered to be the most frequent cause of
nosocomial infections and infections on indwelling medical devices
along with S. epidermidis [2]. Tese two pathogenic bacteria were the
focus of this research due to the diferent studies conducted that
proved the ability of the bacteria to form bioflms [3,4]. Also, they pose
a serious threat which would lead to chronic infections that are not
susceptible to any treatments leading to long-lasting infections or even
death.
Chitosan is a polysaccharide derived from chitin and is abundant in
crustaceans. It is found to have a broad antimicrobial activity against a
wide range of microorganisms [5]. Being a natural polysaccharide,
chitosan exhibits notable biological properties including non-toxicity
and biocompatibility which makes it a good candidate for biomedical
applications [6]. Tis led to studies on chitosan being an efective anti-
bioflm agent by penetrating bioflms present, particularly in medical
devices. By doing so, chitosan will be able to disrupt the microbial cell
membrane [7]. Tus, bioflm formation will be inhibited due to the
disruption of the attachment of the bacteria’s cell membrane to the
solid surfaces. By destroying the bioflm, the bacteria will then be
susceptible to antibiotics which will consequently lead to bacterial cell
death.
Te objective of this study was to examine the anti-bioflm activity
of chitosan from crab and shrimp species on the established bioflms of
Pseudomonas aeruginosa and Staphylococcus aureus.
Limitations of the study
Tis study was done with limitations during the experimental
procedures due to the availability of the resources. Te degrees of
deacetylation of the chitosan samples were not determined. Te
chitosan samples were only stored in a regular transparent containers
and were placed in a refrigerator without controlling temperature.
Tere were only two concentrations (2.5 g/L and 10 g/L) used for this
particular study.
Aurestila et al., J Pharmacogn Nat Prod 2018, 4:1
DOI: 10.4172/2472-0992.1000149
Research Article Open Access
J Pharmacogn Nat Prod, an open access journal
2472-0992
Volume 4 • Issue 1 • 1000149
Journal of
Pharmacognosy & Natural Products
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ISSN: 2472-0992