Scientists identify significant increase in new MRSA strains in non hospital environment

March 5, 2014

Microbiologists from the Dental School in Trinity College Dublin in collaboration with the National MRSA Reference Laboratory at St. James's Hospital Dublin and Alere Technologies in Germany have identified significant increases in the prevalence, genetic diversity and antimicrobial resistance of PVL-positive MRSA circulating in Ireland in the ten years between 2002-2011. These findings have just been published in the March 2014 issue of a leading, peer reviewed international journal, The Journal of Clinical Microbiology.

PVL-positive MRSA are more likely to be found among individuals in the community rather than in a hospital setting which is where MRSA is usually associated. The Panton-Valentine leukocidin (PVL) toxin can enhance the ability of S. aureus (the bacteria Staphylococcus aureus) to cause disease through the destruction of white blood cells and damage to skin and soft tissues.

Among MRSA samples submitted to the Irish National MRSA Reference Laboratory between 2002 and 2011, the authors identified a 44-fold increase in the prevalence of PVL-positive MRSA and a six-fold increase in the number of PVL-positive MRSA samples resistant to multiple antibiotics.

Unlike MRSA strains that traditionally cause invasive infections among older and vulnerable patients in hospitals, many of whom may have underlying infections, these PVL-positive MRSA strains were predominantly identified among younger individuals in the community and were mostly associated with skin and , although serious and life threatening bloodstream infections and necrotising pneumonia were also identified.

Commenting on the significance of the findings, Professor David Coleman, Professor and Chair of Oral and Applied Microbiology, School of Dental Science, Trinity said: "The increased burden of PVL-positive and multi-antibiotic resistant PVL-positive MRSA in Ireland over the last decade is a worrying development and enhanced surveillance in both hospitals and communities is vital to ensure that these strains do not spread and become more established. Rapid and informative high-throughput molecular typing using DNA microarrays and ultimately whole-genome sequencing will be essential in preventing the spread of these strains".

Using high-throughput DNA microarray profiling and molecular typing, the authors, Professor David Coleman, Dr Anna Shore and Sarah Tecklenborg of the Dental School Microbiology Unit in Trinity, identified an unprecedented level of genetic diversity among PVL-positive MRSA and PVL-positive methicillin-susceptible S. aureus (MSSA) in Ireland. In fact, sixteen distinct clones of PVL-positive MRSA and five additional PVL-positive MSSA clones were identified. This diverse range of PVL-positive MRSA strains circulating appears to have increased in recent years and international travel is likely to have been a significant contributory factor. Clusters of PVL-positive MRSA were also identified within families and among patients in hospitals, highlighting the serious challenge that these MRSA strains present for infection prevention and control and for the treatment of infections caused by these organisms both in hospitals and in communities.

Dr Brian O'Connell, Director of the National MRSA Reference Laboratory (NMRSARL) remarked: "NMRSARL has been providing a service for the detection of PVL-positive S. aureus for over 10 years and has been instrumental in delineating the emergence of these strains in Ireland. This paper details the diversity of the strains that are circulating and highlights the importance of continued surveillance, co-ordinated by a national reference laboratory, as some of these strains may cause prolonged and protracted outbreaks in the future".

Explore further: Dangerous form of MRSA, endemic in many US hospitals, increasing in UK

More information: "Panton-Valentine Leukocidin-Positive Staphylococcus aureus in Ireland from 2002 to 2011: 21 Clones, Frequent Importation of Clones, Temporal Shifts of Predominant Methicillin-Resistant S. aureus Clones, and Increasing Multiresistance." J. Clin. Microbiol. March 2014 52:3 859-870; published ahead of print 26 December 2013, DOI: 10.1128/JCM.02799-13

Related Stories

Dangerous form of MRSA, endemic in many US hospitals, increasing in UK

October 23, 2012
Prevalence of a particularly dangerous form of methicillin resistant Staphylococcus aureus (MRSA) jumped three-fold in just two years, in hospitals in the United Kingdom, according to a paper in the October 2012 Journal of ...

MRSA skin infections up, linked to furunculosis

July 27, 2012
(HealthDay) -- The incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in the United States is increasing and is associated with follicular infection, most commonly folliculitis followed ...

MRSA strain gained dominance with help from skin bacteria

December 17, 2013
Scientists believe they have an explanation for how the most common strain of methicillin-resistant Staphylococcus aureus (MRSA) rapidly rose to prominence. Research published in mBio, the online open-access journal of the ...

Copious community-associated MRSA in nursing homes

October 24, 2013
More than one quarter of residents of 26 nursing homes in Orange County, California carry community-associated methicillin-resistant Staphylococcus aureus (MRSA), which spread more easily, and may cause more severe infection ...

Drug-resistant MRSA bacteria: Here to stay in both hospital, community

March 15, 2013
(Medical Xpress)—The drug-resistant bacteria known as MRSA, once confined to hospitals but now widespread in communities, will likely continue to exist in both settings as separate strains, according to a new study.

Recommended for you

Google searches can be used to track dengue in underdeveloped countries

July 20, 2017
An analytical tool that combines Google search data with government-provided clinical data can quickly and accurately track dengue fever in less-developed countries, according to new research published in PLOS Computational ...

MRSA emerged years before methicillin was even discovered

July 19, 2017
Methicillin resistant Staphylococcus aureus (MRSA) emerged long before the introduction of the antibiotic methicillin into clinical practice, according to a study published in the open access journal Genome Biology. It was ...

New test distinguishes Zika from similar viral infections

July 18, 2017
A new test is the best-to-date in differentiating Zika virus infections from infections caused by similar viruses. The antibody-based assay, developed by researchers at UC Berkeley and Humabs BioMed, a private biotechnology ...

'Superbugs' study reveals complex picture of E. coli bloodstream infections

July 18, 2017
The first large-scale genetic study of Escherichia coli (E. coli) cultured from patients with bloodstream infections in England showed that drug resistant 'superbugs' are not always out-competing other strains. Research by ...

Ebola virus can persist in monkeys that survived disease, even after symptoms disappear

July 17, 2017
Ebola virus infection can be detected in rhesus monkeys that survive the disease and no longer show symptoms, according to research published by Army scientists in today's online edition of the journal Nature Microbiology. ...

Mountain gorillas have herpes virus similar to that found in humans

July 13, 2017
Scientists from the University of California, Davis, have detected a herpes virus in wild mountain gorillas that is very similar to the Epstein-Barr virus in humans, according to a study published today in the journal Scientific ...

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.