Staphylococcus epidermidis is a common skin bacteria that can cause infections when entering the bloodstream. It often forms biofilms, which make infections difficult to treat and allow bacteria to become antibiotic resistant. The study aims to analyze differences in antibiotic susceptibility between antibiotic resistant and non-resistant S. epidermidis strains that do not produce biofilms. By comparing their expressed proteins, the study seeks to better understand antibiotic resistance in S. epidermidis to provide insight into device-related infections.

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CHAPTER 1
INTRODUCTION
1.1 Background
Staphyloccocus epidermidis is a common bacteria found on healthy human skin
however if it enters the human skin and into the blood stream, it is considered as a
pathogen (Conlan et al., 2012). S. epidermidis is coagulase-negative, catalase
positive, gram-positive cocci with the ability to utilize glucose as source of energy
under anerobic conditions (Jones et al.,1963). S. epidermidis is also a biofilm
producing bacteria (Fey & Olson, 2010).
Biofilm is often associated with chronic persistent infection because they have
extreme tolerance against antimicrobial agents (Cabrera-Contreras et al., 2013).
Biofilm are made up of multilayered cell clusters embedded in a matrix of
extracellular polysaccharide (Shunmugaperumal., 2010). The microbes present in the
biofilm are hard to be treated under clinical settings due to the difficulty in
penetrating the biofilm. The microbes may or may not be antibiotic resistant but the
presence of biofilm allows it to be antibiotic resistant while in the biofilm
(Shunmugaperumal., 2010). Antibiotic treatment will be blocked by the biofilm
before it could get to the microorganism within.
Antimicrobial resistance (AMR) can be defined as resistance of a certain
microorganism against an antimicrobial medicine to which it was originally sensitive
(Sosa et al., 2009). Microorganisms which are resistant against antimicrobial
treatment are able to withstand the attacks from antibiotics and other antimicrobial
medicines thus cause the standard treatment procedure to be ineffective and allow the
infection to persist and prolong the illness.
Antibiotic treatment often proves to be ineffective against established, mature
biofilm as the treatment may have temporary effect on both inflammation and
healing but sometimes may also have the opposite effect (Cabrera-Contreras et al.,

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2013). Consequent antibiotic treatment may allow biofilm producing bacteria to
develop a resistance against the antibiotic and cause the infection to worsen.
Many researches indicate that S. epidermidis is one of the most common causes for
nosocomial infection associated with indwelling medical devices (Cabrera-Contreras
et al., 2013; Cheung & Otto, 2010; Conlan et al., 2012). Clinical S. epidermidis
isolates shows an exceptionally high phenotypic and genotypic flexibility. Therefore,
variants from one parent strain may vary in terms of morphology of the colony,
growth rate, hemolysis, biofilm formation and antibiotic susceptibility (Kozitskaya et
al., 2013).
The study focuses on analyzing the differences in antimicrobial susceptibility of
antibiotic resistant and non-antibiotic resistant strains of non-biofilm producer S.
epidermidis. Through proteomics approach, proteins expressed by antibiotic resistant
and non-antibiotic resistant of non-biofilm producing S. epidermidis will be
compared to observe the differences and similarities between the proteins present in
both groups.
The study may also highlight the unique proteins expressed by antibiotic resistant
and non-antibiotic resistant of non-biofilm producer S.epidermidis and its relation to
antibiotic resistance. Further understanding on antimicrobial resistant ability of S.
epidermidis will provide better insight on infections related to indwelling medical
devices.
1.2 Problem Statement
The numbers of patients with indwelling medical devices are ever increasing;
however, the insertion of foreign materials into the human body has led to special
complications associated with a definite risk of bacterial and fungal infections. S.
epidermidis have emerged as the leading cause of nosocomial infections related to
indwelling medical devices. The problem lies with the ability of S. epidermidis to
withstand antibiotic treatment. Furthermore, antimicrobial resistance (AMR) is a
very serious global problem because it makes it difficult to treat infections leading to
prolonged illness and higher casualty rate. AMR also increases the cost of healthcare
because the infection needs to be treated specifically and different from common

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treatment methods translating into more expensive and longer duration therapies.
There is more to be understood on the antimicrobial resistant ability of S. epidermidis.
Therefore, more studies need to be carried out to obtain further information on
antimicrobial resistant ability of S. epidermidis.
1.3 Significance of Study
Further understanding on antimicrobial resistant ability of S. epidermidis will provide
better insight on infections related to indwelling medical devices. The study focuses
on analyzing the differences in antimicrobial susceptibility of antibiotic resistant and
non-antibiotic resistant strains of non-biofilm producer S. epidermidis. Furthermore,
the study may highlight the role of proteins expressed by both groups and its relation
to antibiotic resistance. The findings from this study can be use as a good candidate
for future study.
1.4 Objectives
The objectives of this research are:
1. To identify the occurences of antibiotic resistant in non-biofilm producer S.
epidermids
2. To compare the proteins expressed by antibiotic resistant and non-antibiotic
resistant in non-biofilm producer S. epidermidis.