The fight against MRSA

I spotted this article yesterday in the Irish Times and felt compelled to share it. It’s a new step in the fight against MRSA…

New research has found that as the superbug MRSA resists antibiotics, it becomes less virulent. 


LIFE IS full of trade-offs, and it seems the hospital-acquired “superbug” MRSA is no exception. A new study led by Irish scientists has discovered that when the bacterium acquires resistance to antibiotics, it becomes less virulent, at least in a lab model.

The finding could help shed light on why patients who have compromised immune systems are particularly vulnerable to healthcare-associated MRSA infections.

MRSA develops when a bacterium called Staphylococcus aureus (SA) acquires resistance to a number of antibiotics and becomes methicillin-resistant Staphylococcus aureus (MRSA).

The new study, just published in the open-access journal PLoS Pathogens, looked at SA and MRSA infections associated with medical devices that are surgically implanted in a laboratory model, explains lead author Dr Jim O’Gara from UCD’s Conway Institute.

“Bacteria are naturally present on the skin, where they often don’t cause any problem. But if they stick onto medical devices that are put into the body they can get access through the skin’s barrier and then they can potentially establish an infection,” he says.

“They will form biofilms, which are communities of bacteria attached to the medical device, and those biofilms are almost indestructible. In that case you have to take the device out and put in a new one, which is not always a trivial thing for the patient.”

O’Gara and a colleague at Beaumont Hospital noticed several years ago that SA and MRSA biofilms looked different.

“Our early research in this area revealed a hugely surprising result – that MRSA and SA use different ways of forming biofilms,” says O’Gara.

Their discovery was that SA bacterial cells use sugars to stick to each other and to surfaces as biofilms, while MRSA instead use proteins to form biofilms.

With funding from the Health Research Board, his group brought the project further and looked at the effects of turning SA into MRSA in the lab. They used a preclinical model that introduced infection by allowing the bacteria to form biofilms on implanted medical devices.

Again, the results far exceeded their expectations: when SA became resistant to the antibiotic methicillin (and so became MRSA), its ability to cause illness was toned down.

“What the data show is that if you take SA and you make it resistant to methicillin, you change the way it forms biofilms, but you also make it less virulent in a preclinical model,” says Dr O’Gara, whose group at UCD worked on the project with colleagues at the University of Bath, Harvard Medical School and the University of Nebraska.

“It’s like the bacteria are making a decision to divert their energy towards becoming resistant to the drugs, and they are not going to expend energy producing as many toxins or enzymes.”

In essence, the findings suggest that hospital-acquired MRSA may have have adapted to the hospital environment by sacrificing virulence for antibiotic resistance, according to O’Gara.

“This trade-off works for the pathogen because patients in hospital, particularly in an intensive care setting, can be very immuno-compromised and the pathogen does not need to be very virulent,” he says. “On the other hand, the bacterium does need to be very antibiotic resistant, due to the necessarily high levels of antibiotic usage in intensive care units.”

O’Gara is now looking into how the discovery could be used to help make MRSA less nasty for patients who get infected. “It may open up new ways to find anti-virulence drugs,” he says.


This article makes great sense to me as it goes some way to explain why my sinuses are chronically infected with MRSA yet I’m otherwise well. It also explains why I’ve had problems over the years with medical implants which have had to be removed having become contaminated with MRSA.

The question is… how the hell do you get rid of MRSA once and for all?

Source: Irish Times HEALTHplus magazine

8 Responses to The fight against MRSA

  1. mizunogirl says:

    There are people who clear from MRSA colonisation, but it is not that common.

    I did want to let you know though, if you are having any more surgical procedures, there is a series of products being used pre-surgically that decolonize a patient for 12 hours. We use it in colonized patients who are having surgery…and post operatively to give the operative site a chance to heal. It’s really pretty neat, though clearly, not a total solution, it allows for much safer surgery.

    • Steph says:


      Welcome to my blog!

      I’m delighted to hear what you’ve told me re products being available to decolonize pre-surgical patients who are carriers of MRSA.

      This is reassuring news and something which I will follow-up on. Could you tell me the name of these products? I wonder if they’re available in Ireland?

      Thanks for visiting.

      • mizunogirl says:

        The ingredients of the product are available in Ireland I am sure. It is not a permanent solution as some of the products if used long term will totally darken and discolor your teeth…but for say 2-5 days it is not so bad… the products that we are using are made by ***** (removed by Editor). I’ll try to find some more answers for you.

  2. Steph says:


    Thanks for that info. As I prefer this to be an ad-free blog, it’d be better if you emailed me the name and type of product.

    See email address by clicking on ‘About’ on blog header.

    Many thanks, Steph

  3. magnumlady says:

    Hi Steph, Just wanted to say I hope you are feeling better.

    • Steph says:


      It’s very kind of you to enquire.

      My medical saga continues with plenty of ups and downs along the way but thankfully, no hospital admissions since last February. I’m aiming to keep it that way!

      It’s lovely to hear from you. I hope all is well with you and yours.

      Cheers! Steph

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