MRSA Statistics in Hospitals

MRSA Statistics: Incidence, Mortality, and Economic Cost

Antibiotic resistance is a major public health concern. Typically, germs such as bacteria can be killed using antibiotics, but some strains develop the ability to evade this treatment, making them hard to kill. One of the most common and dangerous types of antibiotic-resistant bacteria is methicillin-resistant Staphylococcus aureus (MRSA).

What is MRSA?

Staphylococcus aureus (S. aureus) is a type of bacteria that can cause staph infections. Methicillin-resistant Staphylococcus aureus (MRSA) is a type of S. aureus that is resistant to many different antibiotics, making an infection more difficult to treat ^[1].

MRSA infections are usually caused by bacteria entering the body through a wound such as a cut or abrasion. These bacteria are often a problem in healthcare environments such as hospitals or nursing homes, where people are more at risk for infection after undergoing surgery, having a medical device such as a catheter inserted into their body, or being exposed to MRSA colonized individuals (e.g., hospital staff or visitors). People may also become infected with MRSA in their day-to-day lives after coming into contact with other people or things that carry the bacteria. For example, someone may contract MRSA after touching shared items such as sports equipment, surfaces, or needles. Symptoms of MRSA infection include wounds in the skin that won’t heal, pain, and fever. MRSA infections can also cause more serious problems such as pneumonia, bloodstream infections or death [1].

The Centers for Disease Control and Prevention (CDC) categorizes pathogenic bacteria into different threat levels based on things like how common and contagious a strain of bacteria is, how easily it can be prevented and treated, and the overall public health and economic impact of treating infection. The CDC has labeled MRSA as a “serious threat,” indicating that MRSA infections are a major concern that require immediate attention [2].

MRSA Colonization

When MRSA lives on the surface of a person’s skin without causing an active infection, the person is MRSA colonized and described as a carrier. While not infected, MRSA carriers can still spread the bacteria to other people, and carriers are more likely to develop active staph infections later, after having surgery or experiencing disruptions to the immune system.

The nose is a hot spot for MRSA colonization. About a third of the population carries S. aureus bacteria in their noses, and 5% of people are carriers of MRSA [2]. Different groups of people are more or less likely to be MRSA colonization. For example, 7% of people with HIV are MRSA carriers, although prevalence in this group also varies by geographic location [4].

People with certain characteristics are more likely to be MRSA carriers. Some of these factors are [3]:

• Older age (at least 60 years old)
• Chronic diseases or conditions, such as diabetes
• Use of illicit drugs

Recent hospitalization or frequent doctor’s office visits

• Recent use of antibiotics
• Coming into contact with someone who has a MRSA infection

Nasal colonization can lead to future health problems. People with nasal MRSA colonization are 22 times more likely to develop an invasive infection and 36 times more likely to develop a blood infection, known as bacteremia [3].

MRSA Infections

In 2017, there were 119,247 S. aureus bloodstream infections in the United States. This includes methicillin-resistant bacteria as well as methicillin-sensitive S. aureus (MSSA), which can be more easily killed with antibiotics than MRSA [5].

Public health experts and medical centers have been working to try to prevent MRSA infections. Between 2005 and 2012, the number of infections dropped by 17.1% per year [2]. In recent years, however, progress has slowed, and we continue to see similar numbers of MRSA infections each year. Additionally, infections due to MSSA have increased by 3.9% [5].

Demographics for MRSA Infection

While many people are MRSA carriers, only some people will go on to develop bacterial infections. Risk factors for developing symptoms of an active infection include [6]:

• Having a long hospital stay
• Being admitted into an intensive care unit (ICU)
• Using antibiotics
• Undergoing an invasive procedure or surgery
• Being infected with HIV
• Living in a nursing home
• Having an open wound
• Undergoing hemodialysis
• Having a catheter
• Being colonized with MRSA

Studies show MRSA infections are also more common in people who are older, male, or Black. While the incidence rate in the general population in the United States is 31.8 per 100,000, these groups have higher incidence rates of MRSA [7]:

• People 65 years of age or older: 127.7 per 100,000
• People who are Black: 66.5 per 100,000
• Males: 37.5 per 100,000

Additionally, people who inject illicit drugs are much more likely to develop infections. People in this population are 16 times more likely to have a serious MRSA infection [1].

Within the United States, MRSA is often more prevalent in urban areas than rural ones. In one study of nursing homes, researchers found [8]:

• 5% of samples from urban areas had MRSA
• 9% of samples from suburban areas had MRSA
• 0% of samples from rural areas had MRSA

Around the world, the prevalence of MRSA varies widely. Different studies have found that anywhere from 13-74% of S. aureus infections are caused by methicillin-resistant strains [3].

MRSA Prevalence in Children and Infants

In one study, 2.6% of children are carriers of MRSA. Children are more likely to be MRSA colonized if they have had experienced frequent doctor’s visits or hospitalizations. Additionally, children in the study that acquired MRSA from their community, as opposed to in a healthcare setting, were more likely to be Black and on Medicaid. Other risk factors for MRSA colonization are having a pet at home, biting fingernails, and participating in sports [9].

MRSA can also be a major source of infection in neonatal intensive care units (NICU). Around 0.6-8.4% of NICU patients are MRSA colonized or experience infection, depending on the location and on whether there is an active outbreak occurring within the unit.

Healthcare Workers with MRSA

Healthcare workers may frequently come into contact with MRSA as they treat colonized patients, and they may in turn transmit these bacteria to other patients. About 4.6% of healthcare workers are thought to carry MRSA in the nose, throat, or pharynx. Nursing staff are more likely to be MRSA colonized than other types of healthcare workers [11].

Mortality Rates – S. aureus and MRSA

In 2017, the CDC reported that there were 19,832 deaths due to S. aureus infections, which includes MRSA. The mortality rate of hospital-acquired MRSA infections is 29%, and the mortality rate of community-acquired infections is 18% [5]. This amounts to a rate of 6.3 deaths per 100,000 people in the United States [7]. Although men are more likely to get MRSA infections, women are more likely to die from these infections [3].

MRSA can lead to multiple different types of infections, some of which have higher estimated mortality rates than others:

• Pneumonia caused by all strains of S. aureus leads to a mortality rate of 30-40% [6]
• Bloodstream infections caused by S. aureus have a mortality rate of 15-60% [6]
• MRSA-related bacterial endocarditis, an inflammation of the heart’s inner lining, leads to death in about a third of patients [6]
• Surgical site infections caused by MRSA have a mortality rate of 12.9% [12]
• Sometimes, the body has an extreme reaction to an infection, leading to organ damage and in some cases, death. When this reaction, called sepsis, is caused by MRSA, it leads to death in 30-50% of patients [13]

Several risk factors lead to a greater chance of death from MRSA infections. These include older age, alcoholism, heart failure, fever, high white blood cell count, and comorbidities such as immunosuppression, cancer, or liver disease [14,15].

Bacteremia is a severe infection that occurs when bacteria enter the bloodstream. MSSA-related bacteremia is not as likely to be fatal, leading to a 30-day mortality rate of 6% [12]. On the other hand, MRSA bloodstream infections are much more deadly. In one study [15]:

• 7% of patients with MRSA-related bacteremia died within 30 days. 72.6% of these deaths were directly due to infection.
• 4% of patients died within 30-90 days. 60% of these deaths were due to infection.
• 48% of patients within the study died more than 90 days after being diagnosed. 35.7% of the deaths were because of infection.

MRSA bacteremia appears to be less fatal in children, as the mortality rate in this population is about 2% [16].

MRSA Prevention and Treatment

Prevention

Several strategies are available to help reduce MRSA colonization and transmission. Nasal and body decolonization is a widely accepted strategy used in hospitals that can greatly reduce the risk of colonization. In one study, an alcohol-based nasal antiseptic, Nozin® Nasal Sanitizer® killed 99% of S. aureus nasal colonies in healthcare workers [17]. Another healthcare organization implemented decolonization protocols for patients in order to help minimize the number of infections following hip and knee replacement surgeries. When using the same nasal antiseptic and washing the skin with chlorhexidine, the healthcare facility’s rate of surgical site infections (SSIs) following total joint procedures dropped to zero [18].

Treatment

While MRSA is resistant to most strains of antibiotics, it is sensitive to a few others. Vancomycin and daptomycin are frequently used to treat this infection [3]. Nevertheless, people with MRSA infections typically need to stay in the hospital for long periods of time. In one US-wide study, Out of all hospitalizations for S. aureus, about 60% were due to MRSA [19].

Other Impacts of MRSA

MRSA infections don’t always result in death, but they can lead to other health effects that can be long-lasting.

MRSA carriers who have been in the hospital are more likely to be re-admitted within 90 days or to have multiple MRSA-related hospitalizations [20]. This is often due to subsequent MRSA infections such as bacteremia, pneumonia, soft tissue infections, or surgical site infections, which can take a long time to treat [2]. Recent research shows that recurrent MRSA infections may be facilitated by damage to the immune system. MRSA bacteria release toxins that kill muscle cells of the lymphatic vessels, leading to lymphatic system impairment, reduced activation of immune system function and a greater likelihood of future infections [21].

MRSA infections more often lead to complications in children. About 23% of pediatric MRSA patients have complications related to bloodstream infections, including blood clots or spread of infection to other parts of the body [16].

Healthcare Costs

The cost of treating MRSA can add up. U.S. estimates show that [22]:

• Each case of MRSA costs third-party payers, such as insurance companies, employers, and government agencies, between $2,277 and $3,200
• Each case of MRSA costs society $7,070-20,489
• Each year, MRSA costs third-party payers $478 million-2.2 billion
• Each year, MRSA costs society $1.4 billion-13.8 billion

Costs may vary depending on factors like age or disease severity.

Conclusion

MRSA is a type of bacteria that is resistant to many antibiotics, making it difficult to treat. While it can be acquired in community settings after coming into contact with an infected person, it is most often associated with healthcare settings. About 1 out of 20 people carry MRSA colonies without experiencing active infections. However, carriers are more likely to develop infections later after spending time in a healthcare setting or undergoing an invasive procedure. MRSA infections can be very serious, and lead to death for 3 out of 10 people with hospital-acquired MRSA. Treating these infections comes with large economic costs.

Healthcare organizations can take steps to mitigate the risk of MRSA colonization. Evidence shows that nasal colonization is a significant risk factor for infection, yet the nose often goes unaddressed. Nozin programs mitigate the risk of MRSA nasal colonization and continue to demonstrate improved care, at a lower cost. Learn more about how hundreds of hospitals across the country are reducing their MRSA infection rates here.

References:

1. Centers for Disease Control and Prevention. Methicillin-resistant Staphylococcus aureus (MRSA): General Information. Reviewed 2019 June 26. Available from: https://www.cdc.gov/mrsa/community/index.html
2. Centers for Disease Control and Prevention. Methicillin-resistant Staphylococcus aureus (MRSA): Healthcare Settings. Reviewed 2019 February 28. Available from: https://www.cdc.gov/mrsa/healthcare/index.html
3. Hassoun A, Linden PK, Friedman B. Incidence, prevalence, and management of MRSA bacteremia across patient populations-a review of recent developments in MRSA management and treatment. Crit Care. 2017;21(1):211. Published 2017 Aug 14. doi:10.1186/s13054-017-1801-3
4. Sabbagh P, Riahi SM, Gamble HR, Rostami A. The global and regional prevalence, burden, and risk factors for methicillin-resistant Staphylococcus aureus colonization in HIV-infected people: A systematic review and meta-analysis. Am J Infect Control. 2019 Mar;47(3):323-333. doi: 10.1016/j.ajic.2018.06.023.
5. Centers for Disease Control and Prevention. Vital Signs: Epidemiology and Recent Trends in Methicillin-Resistant and in Methicillin-Susceptible Staphylococcus aureus Bloodstream Infections — United States. Morbidity and Mortality Weekly Report. 2019 March 8;68(9):214-219.
6. Siddiqui AH, Koirala J. Methicillin Resistant Staphylococcus Aureus. [Updated 2020 Jul 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482221/
7. Klevens RM, Morrison MA, Nadle J, Petit S, Gershman K, Ray S, Harrison LH, Lynfield R, Dumyati G, Townes JM, Craig AS, Zell ER, Fosheim GE, McDougal LK, Carey RB, Fridkin SK; Active Bacterial Core surveillance (ABCs) MRSA Investigators. Invasive methicillin-resistant Staphylococcus aureus infections in the United States. JAMA. 2007 Oct 17;298(15):1763-71. doi: 10.1001/jama.298.15.1763.
8. Cheatham S, Thapaliya D, Taha M, Milliken K, Dalman MR, Kadariya J, Grenier D, Smith TC. Prevalence of Staphylococcus aureus and methicillin-resistant S. aureus on environmental surfaces in Ohio nursing homes. Am J Infect Control. 2019 Dec;47(12):1415-1419. doi: 10.1016/j.ajic.2019.05.021.
9. Fritz SA, Garbutt J, Elward A, Shannon W, Storch GA. Prevalence of and risk factors for community-acquired methicillin-resistant and methicillin-sensitive Staphylococcus aureus colonization in children seen in a practice-based research network. Pediatrics. 2008 Jun;121(6):1090-8. doi: 10.1542/peds.2007-2104.
10. Nelson MU, Gallagher PG. Methicillin-resistant Staphylococcus aureus in the neonatal intensive care unit. Semin Perinatol. 2012;36(6):424-430. doi:10.1053/j.semperi.2012.06.004
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12. Gurusamy KS, Koti R, Toon CD, Wilson P, Davidson BR. Antibiotic therapy for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections in surgical wounds. Cochrane Database Syst Rev. 2013 Aug 20;(8):CD009726. doi: 10.1002/14651858.CD009726.pub2.
13. World Health Organization. MRSA Survivors Network. Available from: https://www.who.int/patientsafety/patients_for_patient/PFPS-webinar1_2013.pdf
14. van Hal SJ, Jensen SO, Vaska VL, Espedido BA, Paterson DL, Gosbell IB. Predictors of mortality in Staphylococcus aureus Bacteremia. Clin Microbiol Rev. 2012;25(2):362-386. doi:10.1128/CMR.05022-11
15. Guillamet MCV, Vazquez R, Deaton B, Shroba J, Vazquez L, Mercier RC. Host-Pathogen-Treatment Triad: Host Factors Matter Most in Methicillin-Resistant Staphylococcus aureus Bacteremia Outcomes. Antimicrob Agents Chemother. 2018;62(2):e01902-17. Published 2018 Jan 25. doi:10.1128/AAC.01902-17
16. Hamdy RF, Hsu AJ, Stockmann C, Olson JA, Bryan M, Hersh AL, Tamma PD, Gerber JS. Epidemiology of Methicillin-Resistant Staphylococcus aureus Bacteremia in Children. Pediatrics. 2017 Jun;139(6):e20170183. doi: 10.1542/peds.2017-0183.
17. Steed LL, Costello J, Lohia S, Jones T, Spannhake EW, Nguyen S. Reduction of nasal Staphylococcus aureus carriage in health care professionals by treatment with a nonantibiotic, alcohol-based nasal antiseptic. Am J Infect Control. 2014;42(8):841-846. doi:10.1016/j.ajic.2014.04.008
18. Franklin S. A safer, less costly SSI prevention protocol-Universal versus targeted preoperative decolonization. Am J Infect Control. 2020 Apr 28:S0196-6553(20)30135-8. doi: 10.1016/j.ajic.2020.02.012.
19. Klein EY, Jiang W, Mojica N, Tseng KK, McNeill R, Cosgrove SE, Perl TM. National Costs Associated With Methicillin-Susceptible and Methicillin-Resistant Staphylococcus aureus Hospitalizations in the United States, 2010-2014. Clin Infect Dis. 2019 Jan 1;68(1):22-28. doi: 10.1093/cid/ciy399.
20. Quezada Joaquin NM, Diekema DJ, Perencevich EN, Bailey G, Winokur PL, Schweizer ML. Long-term risk for readmission, methicillin-resistant Staphylococcus aureus (MRSA) infection, and death among MRSA-colonized veterans. Antimicrob Agents Chemother. 2013;57(3):1169-1172. doi:10.1128/AAC.01968-12
21. Jones D, Meijer EFJ, Blatter C, et al. Methicillin-resistant Staphylococcus aureuscauses sustained collecting lymphatic vessel dysfunction. Sci Transl Med. 2018;10(424):eaam7964. doi:10.1126/scitranslmed.aam7964
22. Lee BY, Singh A, David MZ, et al. The economic burden of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA). Clin Microbiol Infect. 2013;19(6):528-536. doi:10.1111/j.1469-0691.2012.03914.x