New, dominant MRSA bug could emerge in Irish hospitals, study warns

A new, dominant MRSA bug could emerge in Irish hospitals in the future.

Scientists at Trinity College Dublin examined a large number of different MRSA strains circulating in Irish hospitals between 2000 and 2012.

The information they have gathered will help identify new MRSA strains early so clinicians are well prepared in preventing the spread of the next dominant strain or strains.

The study points out that it has been previously shown that there is a history of strain replacement about once per decade in Ireland.

A recent decline in the MRSA strain that has predominated for more than a decade in Irish hospitals suggests that a novel strain or strains may emerge in the near future.

MRSA (Methicillin-resistant Staphlocouccus aureus) are a major cause of hospital-acquired infection in many countries worldwide.

MRSA bugs have been endemic in Irish hospitals for nearly 40 years, during which time particular MRSA strains have dominated for periods of several years and have then been replaced by different strains.

The ST22-MRSA-IV strain has dominated in Irish hospitals since 2002 and since then, has accounted for up to 80% of life-threatening MRSA bloodstream infections each year.

The scientists found many of the sporadic MRSA were more resistant to drugs and carried genes that made them particularly virulent and aided their spread between different MRSA samples, which, in turn, created more new variants that are more difficult to treat effectively with antibiotics.

One of the study’s authors and chairman of Oral and Applied Microbiology at TCD’s School of Dental Science, David Coleman, emphasised the importance of the research, just published in the leading international journal, Antimicrobial Agents and Chemotherapy.

“Understanding the detailed characteristics of the pool of sporadic MRSA present in Irish hospitals and ongoing surveillance will permit the early identification of emerging new MRSA stains so that appropriate control measures can be put in place to prevent their spread.”

The extensive genetic diversity found among the sporadic MRSA investigated is similar to that previously identified among a large collection of MRSA strains from around the world.

The finding indicates that the MRSA examined are a microcosm of worldwide MRSA and may have been imported into Ireland from different countries.