Mitigating the Risk of Staphylococcus Aureus Healthcare-Associated Infections
An interview with Sue Barnes
Podcast – Episode 34
Jan 14, 2021
In the podcast we are spotlighting: Mitigating the risk of Staphylococcus aureus healthcare associated infections. The patient's own nasal colonization with either the sensitive strain of staph aureus (MSSA) or the resistant strain (MRSA), especially in a high acuity and high-risk patient population like ICU, dramatically increases the risk of infection for peripheral and central line bloodstream infection along with Surgical site infections.
Sue talks strategies. Join Us!
Kara: Let’s dive in. Today we are spotlighting: Mitigating the risk of Staphylococcus aureus healthcare associated infections
Kara Question 1: What is the risk associated with Staphylococcus aureus bacteria in healthcare these days?
Sue Barnes: When a patient has nasal colonization with either the sensitive strain of staph aureus MSSA or the resistant strain MRSA, especially in a high acuity and high-risk patient population like ICU, the risk of infection is dramatically increased including peripheral and central line bloodstream infection. And we know that for MRSA BSI the mortality rate is significant – almost 30%.
Nasal colonization is a tremendous risk factor for device associate infection, which can lead to sepsis and death.
The CDC has recently expressed concern that, despite improvements, MRSA infections are no longer declining, remaining at unacceptably high levels. The CDC also expressed concern that MSSA is even more prevalent than MRSA, has similar mortality rates and is also costly to treat. Because of the clinical risks associated with MRSA colonization, CDC guidelines recommend nasal decolonization for most high-risk patients. To further reduce rates, the CDC recently recommended that facilities try new strategies – this could for example include adding nasal decolonization to sepsis and CLABSI prevention bundles, and transitioning to universal decolonization instead of targeted decolonization to drive rates down further.
This patient safety concern adds to the burden of recently reported increases in HAI occurring as a result of the diversion of infection prevention efforts in many hospitals and healthcare systems due to the pandemic.
Kara Question 2: What strategies does the CDC and other professional organizations recommend to mitigate the risk of MSSA and MRSA in healthcare?
Centers for Disease Control and Prevention (CDC)
For SSI prevention the CDC recommends nasal and skin decolonization for high risk surgical procedures unless the patient is known to be negative for MSSA and MRSA.
ICU: For ICU patients the CDC references the REDUCE study where 3 decolonization protocols were compared. Of the three the most effective was found to be universal decolonization. This protocol eliminated nasal screening, and involved daily CHG bathing, and mupirocin nasal antibiotic ointment for 5 consecutive days. Among patients in these ICUs, the presence of MRSA was reduced 37 percent, and bloodstream infections caused by all pathogens were decreased by 44 percent.
HRET the Health Education and Research Trust in partnership with AHA: recommends CHG bathing and intranasal decolonization with mupirocin, povidone iodine nasal antiseptic, or alcohol-based nasal antiseptic for reducing infection risk.
AHRQ Agency for Healthcare Research and Quality: recommends universal decolonization for ICU patients and eliminating nasal screening
SHEA Society for Healthcare Epidemiology of America provides recommendations for SSI, MRSA bacteremia and neonatal MRSA infection prevention which involve nasal screening and targeted decolonization
So, there is agreement among all of these organizations to use nasal and skin decolonization to reduce MRSA transmission and infection risk – though there is variation regarding approach – whether universal or targeted and the nasal agents used.
Kara Question 3: Is Staph aureus much of a concern for surgical patients?
Actually 80% of SSI can be traced to the patient’s own nasal bacteria which is predominantly staph and strep. 20% of SSI are caused by S. aureus and almost half of these - 44% - are the resistant strain, MRSA. And, we know that MSSA and MRSA predominate as causative pathogens in SSI after orthopedic, cardiac, vascular and gynecologic obstetric surgical procedures. And Mohs dermatologic procedures often performed on the face in close proximity to the nose, are also at high risk of post procedure SA SSI.
Many patients with MRSA/MSSA SSI end up being readmitted to the hospital within 90 days of their surgical procedures, and they are 7X more likely to die postoperatively - as many as 22% will die within one year of the surgical procedure
Of course, we know that the period of greatest risk for contamination of the surgical wound that can lead to post-operative infection is during the surgical procedure, prior to closing the incision. And we focus a lot on preventing that contamination, with PAB, preop bathing, skin prep, nasal decolonization, aseptic technique, etc.
We don’t focus as much on the post-operative period, where the risk of incisional contamination remains until the incision is healed and the skin can again serve as the primary barrier against contamination. This typically takes 5-8 days.
Kara Question 4: What are some of the drawbacks to traditional approaches to contain MRSA.
Sue Barnes: Let’s start with what the traditional approaches are. There are 3 primary strategies taken in hospitals to reduce MRSA transmission risk – there is screen and isolate with contact precautions, screen and treat or decolonize, and then there is universal decolonization which provides active source control
Targeted decolonization or screen and treat, is the approach most commonly employed in ICUs and for preoperative patients. There are a number of downsides to this approach when compared to a universal decolonization protocol where all patients in the hospital or in a specific department are decolonized.
The limitations of screen and isolate and screen and treat includes the fact that colonized patients can be missed – on average 35% of all MRSA colonized patients in a screen and isolate or treat program remain undetected. That’s because typically it is a targeted screening versus universal screening. Also, the screening can yield false negatives, being on average only 70-80 percent effective in detecting S. aureus in the nose. The screen and treat or isolate approaches do not mitigate the risk of patients who can become colonized once they are admitted. Undetected MRSA colonized patients present a risk to other patients in the unit and hospital.
Since the screening is often targeted to high risk patients, the screen and treat and screen and isolate approaches do not provide the same level of prevention care to all patients, but only those at high risk. High risk is defined differently by different states, hospitals and ambulatory surgical centers.
And of course, the screening tests are costly, in addition to the laboratory cost.
And perhaps the greatest limitation of all if that even though MSSA also causes many HAI, Nationally, it accounts for 45-55 percent of S. aureus health care associated infections, there is no active screening done for MSSA. And even in the states such as California where MRSA screening in ICU and for high risk surgical patients is required, screening for MSSA is not.
Kara Question 5: Is this resulting in hospitals shifting to universal decolonization of all at-risk patients?
Sue Barnes: Well for some yes. Universal decolonization has been proven to be the most effective approach in many studies. The REDUCE study published by Dr. Susan Huang is still the preeminent study comparing universal and targeted MRSA decolonization. The study clearly demonstrated the superiority of universal decolonization when compared to screen and treat and screen and isolate for MRSA in the ICU. The study prevented 9 BSIs per 1,000 ICU admissions; equating to an average 23 BSIs avoided annually in a 30 bed ICU with associated cost of $418k/yr. to treat.
The success of this study where all patients were decolonized was due in part to the fact that indwelling devices such as IV and urinary catheters and ETT serve as direct portals of entry for pathogens. If these lines and airways are contaminated with migration of skin or nasal bacteria, unclean hands or the environment, the risk of infection is increased.
And as mentioned the fact that 30-40% of the population is colonized with MSSA, which can also cause all types of HAI. Universal decolonization reduces the risk of these MSSA infections.
Kara: Dr. Mohamad Yassin and I, in our Research Behind Infection Prevention podcast segment, were able to interview Dr. Huang after she published her work on Decolonization to Reduce Post-Discharge Infection Rates Among MRSA Carriers,” from the New England Journal of Medicine. I’ll put a link to that really insightful interview also in the show notes.
Kara Question 6: Sue, Could you share some data on the impact of universal decolonization in preventing surgical site infections and central line-associated bloodstream infections (CLABSI)?
Absolutely – for CLABSI prevention in ICUs there is the Susan Huang study already described. In addition, there was an abstract presented during ID week in 2019 by Adriana Jimenez with Jackson Health System, FL, which demonstrated the benefit of two interventions – universal daily decolonization and use of alcohol based nasal antiseptic instead of mupirocin. When mupirocin was replaced with the alcohol based nasal antiseptic and the protocol was changed from screen and treat to universal decolonization of all patients, not just ICU, there was a 74% reduction in MRSA bacteremia. The 52- month study concluded that hospital-wide universal daily decolonization was more successful than targeted decolonization in the ICU and contact precautions to prevent MRSA bacteremia.
For SSI Prevention – there are many studies I could reference, but will mention one here today. The study was published in AJIC in 2017 by Baylor Ortho and Spine hospital. They replaced mupirocin with alcohol-based antiseptic paired with CHG bathing prior to spine procedures. The nasal antiseptic was also applied postoperatively twice a day until discharge. In addition, surgeons and surgical staff agreed to self-decolonize prior to each surgery, as did PACU staff. The SSI rate during this study was reduced with this change in protocol by 81%.
Kara Question 7: Should HCWs practice nasal decolonization?
Sue Response Well it’s certainly not standard at this time. However, we do know that healthcare workers can transmit MRSA and MSSA to patients via contaminated hands and equipment. Remember the average person – which includes patients, HCWs and providers – touch their noses over 100 times a day, and their faces over 250 times a day – each is a potential opportunity to contaminate hands and then the environment, and/or other people.
In the OR, S aureus pathogens contaminating provider hands and skin surfaces can contaminate aerosolized particles, equipment, and tools such as laryngoscope blades, laryngoscope handles, anesthesia machines, and ventilators.
There have been a couple of studies where nasal decolonization of surgical team member provided an additive effect to the many other SSI prevention measures in place. This makes sense given that masks are not 100% effective especially when wet.
Kara Question 8: Is mupirocin antibiotic ointment the only nasal decolonizing agent available for use in healthcare?
Mupirocin antibiotic ointment is the nasal decolonizing agent which has been around the longest and so has been the most studied. And it has been the most common nasal decolonizing agent until very recently. Mupirocin is typically ordered preoperatively for the patient to self-administer 2-3 times a day for 5 to 7 days before the surgical procedure, and in the REDUCE study was applied to the patient for 5 days. There are numerous downsides to the use of mupirocin including selective mechanism of action (gram + only), 5-day BID course with limited effectiveness until day 3, it is not aligned with antibiotic stewardship due to the incidence of mupirocin resistant MSSA and mupirocin resistant MRSA worldwide and it is only 60% - 93% effective in eliminating staph and strep.
More recently nasal antiseptics have become available both- iodine and alcohol based. These are designed to be applied to the skin at the entrance to the nostrils, just as hand sanitizers are applied to the skin on the hands.
Kara Question 9: What about Flu and COVID-19 – is there any benefit with nasal decolonizing?
It is my understanding of the published studies so far, that bacterial co and secondary infections are infrequent in COVID-19 patients, and viral co-infections are more common. However, up to 75% of patients infected with influenza that go on to acquire pneumonia, are confirmed to have bacterial co-infection. When these infections occur either during or after the flu infection, the patient’s risk of hospital admission, serious morbidity and mortality is increased. Necrotizing pneumonia that is caused by community acquired (MRSA) has a 30% mortality rate. It is well documented that nasal colonization with SA is a significant risk factor for development of secondary bacterial pneumonia in patients infected with Influenza. So yes, nasal decolonizing would be important during the flu season.
Kara Question 10: Sue this has been really informative. Any final thoughts?
I just want to add my personal opinion that given the significant benefit of nasal decolonization in healthcare, I would like to see the same benefit afforded to the community at large. Nasal sanitizers are not in stores yet, but are available via the internet. For anyone who would like more information about how to order them and how to use them, please contact me at firstname.lastname@example.org
Kara Question 11: Sue, please let us know the best ways for everyone to connect with you.
Sue Response: The easiest way is by email – mine is simple my name with middle initial a – so it’s email@example.com. I’m on LinkedIn now too - so (LinkedIn, twitter, Facebook, email).
Kara Wonderful, I will have a link in the show notes on how to connect with Sue. Sue, thank you so much for joining me on the Infection Prevention Spotlight Podcast. I’d love to have you back again in the future, you are a wealth of Infection Prevention knowledge. Also, I want to personally thank you for your dedication and contributions to the field of Infection Prevention, really amazing work – Thank you!
More about Sue Barnes:
Sue Barnes is an independent clinical consultant, since 2016 when she retired as National Infection Prevention Leader for Kaiser Permanente’s 38 hospitals and 673 medical offices.
She is Board certified in Infection Control and Prevention, and was granted the designation of Fellow of APIC in 2015 (FAPIC). She has been in the field of Infection Prevention since 1989. She served on the National APIC Board of Directors from 2010 to 2012, and the San Francisco chapter board of directors for 10 years. She now provides consultative services to several industry partners in addition to AORN, APIC and IDSA.
Best way to reach Sue Barnes: