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Role of endoglycosidases in carbohydrate utilization in group A Streptococcus and Enterococcus faecalis

Jeyapaul, Shamini (2013) MOBN18 20122
Degree Projects in Molecular Biology
Abstract
Popular science summary:

Do bacteria survive in humans by eating the defense molecules during the course of infection?

Enterococcus faecalis (E. faecalis) is a pathogen that can be found in the human gut which causes a wide range of infections including urinary tract infections, cardiovascular infections and bacteremia (presence of bacterial cells in blood stream). These bacteria can also be found in wound infections along with many other types of bacteria. E. faecalis is listed as one of the leading causes of hospital acquired infections commonly occurring after surgery. It is one of the most antibiotic resistant bacteria known to date. Therefore, it is becoming increasingly difficult to treat these bacterial infections.

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Popular science summary:

Do bacteria survive in humans by eating the defense molecules during the course of infection?

Enterococcus faecalis (E. faecalis) is a pathogen that can be found in the human gut which causes a wide range of infections including urinary tract infections, cardiovascular infections and bacteremia (presence of bacterial cells in blood stream). These bacteria can also be found in wound infections along with many other types of bacteria. E. faecalis is listed as one of the leading causes of hospital acquired infections commonly occurring after surgery. It is one of the most antibiotic resistant bacteria known to date. Therefore, it is becoming increasingly difficult to treat these bacterial infections.

Streptococcus pyogenes (S. pyogenes) also known as group A Streptococcus (GAS) is a pathogen exclusively found in humans. It is considered as one of the top 10 pathogens in the world based on death rate. Streptococcal toxic shock syndrome, acute rheumatic fever, necrotizing fasciitis (rapid and progressive infection of skin) are some of the life-threatening infections caused by these bacteria. The versatility of the bacteria in the human host has posed an obstacle in the development of vaccines.

The immune system is the body’s defense against infectious organisms and other invaders. The immune system can be further classified into innate immunity (early nonspecific responses) and adaptive immunity (later specific responses to diseases). One of the important components of adaptive immunity are immunoglobulins. Immunoglobulin G (IgG) the most abundant subtype found in the circulation is a glycoprotein which has a protein part (peptides) and sugar part (as glycans attached to the peptide side chains at a specific site). Both E. faecalis and S. pyogenes secrete a special enzyme that cleaves the glycan molecules attached to IgG at a specific location. By doing so, they impair the structure and function of IgG. EndoE of E. faecalis, in addition to IgG, can cleave the glycans from lactoferrin which is a glycoprotein also found in human milk. The enzyme is called EndoE in E. faecalis and EndoS in S. pyogenes.

Bacteria require carbon sources for growth and can survive on variety of sugars. This report investigated whether these bacteria are able to utilize the glycans of host glycoproteins for growth with the help of enzyme activity. Growth experiments revealed that IgG supports E. faecalis growth due to EndoE activity whereas role of lactoferrin is not clear. Although IgG supports S. pyogenes growth, it is not dependent on EndoS activity. If bacteria start to feed on IgG, then IgG cannot fight against foreign molecules that enter the body. Instead they contribute to pathogenesis and persistence of infection.


Supervisor: Mattias Collin
Master´s Degree Project in Molecular Biology – Microbiology, 2013
Department of Biology, Lund University
Department of clinical Sciences, Division of Infection medicine, Lund University (Less)
Please use this url to cite or link to this publication:
author
Jeyapaul, Shamini
supervisor
organization
course
MOBN18 20122
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
3632861
date added to LUP
2013-04-11 11:00:37
date last changed
2013-04-11 11:00:37
@misc{3632861,
  abstract     = {Popular science summary:

Do bacteria survive in humans by eating the defense molecules during the course of infection?

Enterococcus faecalis (E. faecalis) is a pathogen that can be found in the human gut which causes a wide range of infections including urinary tract infections, cardiovascular infections and bacteremia (presence of bacterial cells in blood stream). These bacteria can also be found in wound infections along with many other types of bacteria. E. faecalis is listed as one of the leading causes of hospital acquired infections commonly occurring after surgery. It is one of the most antibiotic resistant bacteria known to date. Therefore, it is becoming increasingly difficult to treat these bacterial infections.

Streptococcus pyogenes (S. pyogenes) also known as group A Streptococcus (GAS) is a pathogen exclusively found in humans. It is considered as one of the top 10 pathogens in the world based on death rate. Streptococcal toxic shock syndrome, acute rheumatic fever, necrotizing fasciitis (rapid and progressive infection of skin) are some of the life-threatening infections caused by these bacteria. The versatility of the bacteria in the human host has posed an obstacle in the development of vaccines.

The immune system is the body’s defense against infectious organisms and other invaders. The immune system can be further classified into innate immunity (early nonspecific responses) and adaptive immunity (later specific responses to diseases). One of the important components of adaptive immunity are immunoglobulins. Immunoglobulin G (IgG) the most abundant subtype found in the circulation is a glycoprotein which has a protein part (peptides) and sugar part (as glycans attached to the peptide side chains at a specific site). Both E. faecalis and S. pyogenes secrete a special enzyme that cleaves the glycan molecules attached to IgG at a specific location. By doing so, they impair the structure and function of IgG. EndoE of E. faecalis, in addition to IgG, can cleave the glycans from lactoferrin which is a glycoprotein also found in human milk. The enzyme is called EndoE in E. faecalis and EndoS in S. pyogenes.

Bacteria require carbon sources for growth and can survive on variety of sugars. This report investigated whether these bacteria are able to utilize the glycans of host glycoproteins for growth with the help of enzyme activity. Growth experiments revealed that IgG supports E. faecalis growth due to EndoE activity whereas role of lactoferrin is not clear. Although IgG supports S. pyogenes growth, it is not dependent on EndoS activity. If bacteria start to feed on IgG, then IgG cannot fight against foreign molecules that enter the body. Instead they contribute to pathogenesis and persistence of infection.


Supervisor: Mattias Collin
Master´s Degree Project in Molecular Biology – Microbiology, 2013
Department of Biology, Lund University
Department of clinical Sciences, Division of Infection medicine, Lund University},
  author       = {Jeyapaul, Shamini},
  language     = {eng},
  note         = {Student Paper},
  title        = {Role of endoglycosidases in carbohydrate utilization in group A Streptococcus and Enterococcus faecalis},
  year         = {2013},
}