Identification of potential protein biomarkers from salmonella enterica subspecies enterica serovar typhi biofilm
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Date
2013-07
Authors
Lee, Yen Lurk
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Salmonella Typhi is a human specific pathogen which causes typhoid fever. It is a
major health problem in developing countries including Malaysia. Although
prevention and medical treatment are available, typhoid still persists. One of the
major factors contributing to typhoid persistence is the existence of asymptomatic
typhoid carriers. Biofilm formation in the human gallbladder is postulated to be
associated with development of carriers. Formation of biofilm enables the bacteria to
evade the host immune system and resist antibiotics. In order to understand the
formation of biofilm, a S. Typhi biofilm culture method was developed to facilitate
the biofilm protein expression and antibiotic resistance studies.
In this study, S. Typhi biofilm was cultured in vitro by mimicking the human
gallbladder environment using nutrient broth containing bile, glucose, and salts.
Biofilm proteins were harvested and compared with the planktonic counterpart using
2D-PAGE. Fifteen unique biofilm protein spots were identified and were excised for
further analysis using MALDI-TOF. One of the biofilm proteins identified was TolC,
a virulence and persistence factor of the bacteria. It was also found to be empirically
upregulated in response to bile concentration in the biofilm culture medium. Biofilm
antibiotic resistance was assessed by challenging the biofilm bacteria cells with
ampicillin, chloramphenicol, kanamycin, and tetracycline. The results showed that S.
Typhi biofilm was generally more resistant to certain antibiotics such as
chloramphenicol, kanamycin, and tetracycline, but remained susceptible to
ampicillin.
The S. Typhi biofilm culture method developed in this study could be used as a
model for the typhoid carrier stage and also to screen antibiotics required for
elimination of S. Typhi biofilm in chronic patients. Biofilm proteins identified in this
study are potential biomarker candidates for typhoid carrier identification.
Furthermore, since S. Typhi biofilm is a new research field, knowledge generated in
this study added significant value to the knowledge pool of biofilm and provide clues
for better understanding of the mechanism of biofilm formation.
Description
Keywords
Typhoid