MRSA tailors virulence mechanisms to the hospital setting

April 25, 2012, University College Dublin

(Medical Xpress) -- In the hospital environment where antibiotic usage is extremely high, it seems that healthcare associated methicillin resistant Staphylococcus aureus (MRSA) has cleverly adapted for survival.

The findings of new research by UCD scientists led by Conway Fellow, Dr Jim O’Gara from UCD School of Biomolecular & Biomedical Science indicate that the so-called ‘super-bug’, MRSA sacrifices virulence potential for antibiotic resistance.

When the pathogen Staphylococcus aureus becomes resistant to methicillin, it also alters the way in which it produces a biofilm. This coating by colonies of the pathogen can form on prosthetic devices implanted in patients for diagnostic or therapeutic reasons and cause infection.

Patients with implanted devices are typically in an intensive care setting in hospital and have lowered immunity. They are more susceptible to infection even from a less virulent MRSA.

Describing the study that was published earlier this month in PLoS Pathogens, Dr O’Gara said, “We introduced a methicillin resistance gene into pre-clinical isolates of S. aureus in the laboratory to produce a high level resistant form of the pathogen.

We worked with Professor Brendan Loftus in the UCD Conway Genomics Core to identify the genetic changes in this modified strain of the pathogen using whole genome sequencing. These genetic changes led to biofilm development being mediated through an alternate pathway while also causing significantly reduced virulence in a murine model of device infection.”

The findings indicate that has honed its arsenal of virulence mechanisms to suit the hospital environment favouring antibiotic resistant over virulence while retaining its biofilm forming capacity and using implanted medical devices in immune-compromised patients as the optimum route to infection.

Device associated infections are difficult to treat and also necessitate the removal of the device, which in itself is not a trivial procedure for the patient. Understanding the ways by which biofilms are produced is the initial challenge to developing therapeutics to treat staphylococcal biofilm infections.

This research funded the Health Research Board, IRCSET and Healthcare Infection Society (UK) was carried out in collaboration with research groups in the University of Bath, University of Nebraska Medical Centre and Harvard Medical School.

Related Stories

Recommended for you

Creation of synthetic horsepox virus could lead to more effective smallpox vaccine

January 19, 2018
UAlberta researchers created a new synthetic virus that could lead to the development of a more effective vaccine against smallpox. The discovery demonstrates how techniques based on the use of synthetic DNA can be used to ...

Study ends debate over role of steroids in treating septic shock

January 19, 2018
The results from the largest ever study of septic shock could improve treatment for critically ill patients and save health systems worldwide hundreds of millions of dollars each year.

New approach could help curtail hospitalizations due to influenza infection

January 18, 2018
More than 700,000 Americans were hospitalized due to illnesses associated with the seasonal flu during the 2014-15 flu season, according to federal estimates. A radical new approach to vaccine development at UCLA may help ...

Flu may be spread just by breathing, new study shows; coughing and sneezing not required

January 18, 2018
It is easier to spread the influenza virus (flu) than previously thought, according to a new University of Maryland-led study released today. People commonly believe that they can catch the flu by exposure to droplets from ...

Zika virus damages placenta, which may explain malformed babies

January 18, 2018
Though the Zika virus is widely known for a recent outbreak that caused children to be born with microencephaly, or having a small head, and other malformations, scientists have struggled to explain how the virus affects ...

Certain flu virus mutations may compensate for fitness costs of other mutations

January 18, 2018
Seasonal flu viruses continually undergo mutations that help them evade the human immune system, but some of these mutations can reduce a virus's potency. According to new research published in PLOS Pathogens, certain mutations ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.