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Methicillin-resistant Staphylococcus aureus and Staphylococcus aureus

The rationale for surveillance

A burdensome infection

In the US alone, staphylococcus aureus (SA) and methicillin resistant staphylococcus aureus (MRSA) infections burden the healthcare system with approximately $9.5 billion and $20 billion in annual care costs, respectively.1,2

Moreover, these staggering financial figures only capture a fraction of the burden attributed to MRSA and SA infections. Hospitalised patients endure prolonged stays and suffering, resulting in tangible and intangible costs that add to the considerable price tags associated with the increased morbidity and mortality rates due to MRSA/SA infections.

MRSA is a bacterial infection which causes the same infection as SA, however it is dangerous due to its resistance to many antibiotics that successfully treat normal SA. It is transmitted to an individual through bacterial contact with a wound, cut, or even ingrown hairs and razor burn on the skin’s surface. This transmission can come from the skin of another person with SA, or from a colonised environmental surface. When in the body it multiplies, invades host tissue, and causes severe inflammation and infection.3

It’s well established that SA is commonly found as part of the normal flora on the skin and in the respiratory tract of 30% of the population without negative effects on the carrier.4 However, up to 93% of hospital-acquired SA infections are caused by a patient’s own colonised flora.

The need for reliable surveillance

The bacteria often reside harmlessly on the body in specific locations. However, when they are displaced inside the body or into other cavities, the bacteria will begin to cause symptoms.5 Thus colonised patients, specifically, are at increased risk of developing surgical site infections, which lead to prolonged hospital stays, higher costs, and significantly increased risk of death. In fact, SA nasal carriers are 9 times more likely to develop a surgical site infection compared to non-carriers.6 Nasal carriage of SA is also a major risk factor for self-infection in dialysis, ICU, and burn patients.7

A surgical site infection related to undetected MRSA/SA results in:

  • Prolonged hospital stays
  • Increased resistance of microorganisms to antimicrobials
  • Emotional burden for patients and their families
  • Increased number of deaths

The substantial human suffering and financial burden of these endemic infections prompt an urgent need for healthcare facilities to establish effective surveillance for infection control and prevention.

The role of Microbiology labs

A study published in the New England Journal of Medicine demonstrated that programs employing rapid molecular detection of SA colonisation followed by targeted decolonisation resulted in a 60% reduction in surgical site infections.8

To address the evolving problem of MRSA/SA, growing numbers of hospitals are partnering with microbiology labs to incorporate MRSA/SA screening and surveillance to identify and control these infections.

Microbiology labs are the first lines of defence for detection of MRSA/SA unexpected pandemics, and outbreaks. By implementing a reliable surveillance program that rapidly and accurately detects colonised patients, clinical microbiology and infection control can help reduce the worldwide burden and spread of these costly infections.

“Circumventing the traditional ‘culture and subsequent identification’ procedures in medical microbiology, molecular testing provides unrivalled speed to result for MRSA and C. diff colonisation and/or infection.

Depending on the local infrastructure, same-day results are within reach. So, clinicians can initiate appropriate isolation measures or effective antibiotic eradication schemes without delay—for the benefit of both the affected patient and the contact persons.”

Professor Dr. Udo Reischl

References:

  1. Noskin GA, Rubin RJ, Schentag JJ, et al. Budget impact analysis of rapid screening for Staphylococcus aureus colonisation among patients undergoing elective surgery in US hospitals.Infect Control Hosp Epidemiol. 2008;29(1):16-24. doi:10.1086/524327.
  2. Saadatian-Elahi M, Teyssou R, Vanhems P. Staphylococcus aureus, the major pathogen in orthopaedic and cardiac surgical site infection: a literature review.Int J Surg. 2008;6(3):238-245. doi:10.1016/j.ijsu.2007.05.001.
  3. Fraunholz, M., & Sinha, B. (2012). Intracellular staphylococcus aureus: Live-in and let die. Frontiers in Cellular and Infection Microbiology,2. doi:10.3389/fcimb.2012.00043
  4. Centers for Disease Control and Prevention. General information about MRSA in healthcare settings.http://www.cdc.gov/mrsa/healthcare/index.html. Published September 2013. Updated April 2014. Accessed April 15, 2014.
  5. Coughenour, C., Stevens, V., & Stetzenbach, L. D. (2011, September). An evaluation of methicillin-resistant Staphylococcus aureus survival on five environmental surfaces. www.ncbi.nlm.nih.gov/pubmed/21612512. Retrieved July 19, 2017.
  6. Critchley, IA. Eradication of MRSA nasal colonisation as a strategy for infection prevention. Drug Discov Today Ther Strateg. 2006;3(2):189-195. doi:10.1016/j.ddstr.2006.05.003.
  7. Yu VL, Goetz A, Wagener M, et al. Staphylococcus aureus nasal carriage and infection in patients on hemodialysis.N Engl J Med. 1986;315(2):91-96. doi:10.1056/NEJM198607103150204.
  8. Bode LGM, Kluytmans JA, Wertheim HF, et al. Preventing surgical-site infections in nasal carriers of Staphylococcus aureus.N Engl J Med. 2010;362(1):9-17. doi:10.1056/NEJMoa0808939.