The War Against MRSA

By Cynthia Zips, M, SM(ASCP), CICOctober 25, 2013

MPH 500- Fundamentals of Public Health – Section 01- Fall A 2013

Instructor: Madeline Angela Meyer, PhD

The Epidemiology of MRSA

• Methicillin-resistant Staphylococcus aureus (MRSA) has become a prevalent pathogen in the United States.

• 94,000 invasive infections in 2005

• 18,500 deaths (mortality rate 20%) (Hirschmann, 2007)

The Epidemiology of MRSA

• Healthcare Associated Infections–Deep wound and invasive infections

• Community Acquired Infections–Usually soft tissue infections

(Farley, 2008)

The Epidemiology of MRSA

• 25% to 30% of people are colonized with MRSA (NIOSH, 2013)

• Colonization often precedes invasive infection

• In 2003, up to 60% of hospitalized patients with MRSA colonization developed an infection, and 5–15% of colonized residents in a LTCF developed an MRSA infection (McNeil, 2003).

Biostatistics of MRSA

1974 1995 20040%

10%

20%

30%

40%

50%

60%

70%

2%

22%

64%

Number of MRSA Infections

MRSA In-fections

MRSA infections increased between 1974 and 2004

(Klevens, 2006)

MRSA invasive infections have caused• an estimated 278,000 hospitalizations in 2005 (Klein, 2008)• 56% of device related infections in 2006 and 2007 (Hidron,

2008)

Device related infections include• Central Line Associated Bloodstream Infections (CLABSI)• Ventilator Associated Pneumonia (VAP)• Catheter Associated Urinary Tract Infections (CAUTI)

Biostatistics of MRSA

Biostatistics of MRSA

Because MRSA is so invasive and so pathogenicmeasures were implemented to reduce infection.

Because of measures to reduce transmission of MRSA,infections were reduced!

Break the Cycle

Prevent Transmission

In Order to Prevent Colonization

In Order to Prevent Infection

Biostatistics of MRSA

• Recent studies indicate Healthcare Associated Invasive Infections due to MRSA have been reduced by more than 54.2% between 2005 and 2011.

• Community associated infections have decreased by only 5%.

(Laidman, 2013)

Biostatistics of MRSA

Success in the war against MRSA does not mean the war is over.

In a recent study, 1 in 5 patients with hospital onset MRSA infection died, which is still a mortality rate of 20%. (Chen, 2013)

So the war against MRSA continues….

The Biomedical Aspect of MRSA

MRSA produces toxins that help it to be invasive

• Hemolysin- lyses red blood cells (Koneman, 1988)

• Coagulase –prevents phagocytosis (Koneman, 1988)

• Hyaluronidases-degrades the cellular matrix of tissue (Hart, 2009)

• Exfoliatins – sloughing (Koneman, 1988)

• Leukocidins- destroys leukocytes, causes necrosis (Adler, 2006)

• Lipases-hydrolyzes lipids in the skin, reduces the phagocytic killing of Staph aureus (Rollo, 1988)

• Nuclease- inhibits antimicrobial activity of neutrophils (Berends, 2010)

The Social Aspect of MRSA

• MRSA is spread by touch or contact with infected or colonized people, or surfaces.

• MRSA is viable as long as 56 days (Huang, 2006)

• MRSA transmission is a problem where people gather and interact with each other.

Social Aspect of MRSA

• CDC has established guidelines to prevent the transmission of MRSA– Hand hygiene– Isolation practices– Gloving – Gowning– Good cleaning and disinfection of patient care

equipment and environments(HICPAC, 2007)

Government Policy and MRSA

CMS and other regulatory agency requirements–Policy for the prevention of MRSA and other

multidrug-resistant organisms–Mandatory reporting –Public reporting –Reduced reimbursements for HAIs

Because of the high cost of infection, it is now more cost-effective to implement measures to prevent infection. (CMS, 2013)

Conclusion• 85% of all HAIs were caused by MRSA in 2007 (APIC, 2007)

• Measures were implemented to reduce MRSA transmission

• A study in 2011 indicates Hospital Onset invasive MRSA were decreased 54.2% from 2005 (Laidman, 2013)

• Success means that we are on the right track

• Measures already implemented should be continued.

• The war against MRSA goes on.

Adler , A., et.al., Leukocidin-producing Staphylococcus aureus, Emerg Infect Dis. ,2006 November; 12(11): 1789-1790.

Berends, E., et.al., Nuclease Expression by Staphylococcus aureus Facilitates Escape from Neutrophil Extracellular Traps, J Innate Immun., 2010, October; 2(6):576-586.

Chen, L., The Changing Epidemiology of Methicillin-Resistant Staphylococcus aureus: 50 years of a Superbug. American Journal of Infection Control. 2013; 41:448-451.

CMS, (2013), Acute Inpatient PPS.

Farley, J., Epidemiology, Clinical Manifestations, and Treatment Options for Skin and Soft Tissue Infection Caused by Community-acquired Methicillin-resistant Staphylococcus aureus, J AM Acad Nurse Pract, 2008, February; 20 (2):85-92.

Hart, M., Hart, M., Roop, A., Genotypic and Phenotypic Assessment of Hyaluronidase Among Type Strains of a Select Group of Staphylococcal Species, Int J Microbiol. , 2009; 2009: 614371

HICPAC, 2007, Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings 2007. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention (CDC), Atlanta, GA 30333

Hidron, A., et.al., Infecti Control Hosp Epidemiol; 2008; 29:996-1011.

References

Hirschmann, J., The Epidemiology of MRSA, Journal Watch Dermatology, 2007; 6(10).

Huang, R., Mehta S., Weed, D., Price, C., Methicillin-Resistant Staphylococcus aureus Survival on Hospital Fomities., Infect Control Hosp Epidemiol, 2006; 27: 1267-1269.

Klein, E et. al., Emerging Infectious Diseases., 2007; 13:1840-6.

Klevens, R.M., et.al., Clinical Infectious Disease; 2006; 42:389-91

Koneman, E., Color Atlas and Textbook of Diagnostic Microbiology, 3rd Edition, 1988

Laidman, J., MRSA: Hospital-Related Infections Fell 50% From 2005 to 2011, Medscape Medical News, Sept 16, 2013.

McNeil, S., Mody, L., Bradley, S., Methicillin-resistant Staphylococcus aureus and Vancomycin-resistant Enterococci Among Older AdultsFocus on Long-term Care Facilities, Geriatrics &Aging, October 2003, Vol 6, Num 9

References

The War Against MRSA