Maureen Spencer, RN,M.Ed., CICInfection Control Manager

New England Baptist HospitalBoston, Ma.

Email: mpspence@nebh.org617 754-5332

www.workingtowardzero.com

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What is Staphylococcus aureus?

Staphylococcus aureus, "staph," are bacteria commonly carried on the skin or in the nose of healthy people.

They are gram positive (purple colored) cocci in clusters on gram stain

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Overview of Antibiotic Resistance

Unnecessary antibiotic use. excessive and unnecessary antibiotic use.

Antibiotics in food and water. Antibiotics in livestock find their way into municipal water systems when the runoff from feedlots contaminates streams and groundwater.

Germ mutation. Antibiotics don't destroy every germ they target. Germs learn to resist others and mutate much more quickly than new drugs can be produced.

Transfer Factors – survival of the fittest – quantum communication

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Past 60 years – Resistance

50-70’s Staph aureus developed Penicillin resistance (blocking enzyme called penicillinase)

70’s Pencillinase resistant antibiotics (methicillin, oxacillin)

Early 1980’s – first cases of MRSA - Methicillin-Resistant Staphylococcus aureus in US

Early 1990’s Vancomycin Resistant Enterococci (VRE)

Early 2000’s CA-MRSA (USA300) Now - V.I.S.A. & V.R.S.A.Vancomycin intermediate and Vanco

resistant strains

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What is MRSA? MRSA is the term used for a

subgroup of bacteria of the Staphylococcus aureus species that are resistant to the usual antibiotics used in the treatment of infections

Not just resistant to Methicillin - often have resistance to many antibiotics traditionally used against S.aureus.

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How Does it Get Resistant?

Presence of the mec gene in the bacteria.

This alters the site at which methicillin binds to kill the organism.

Hence, methicillin and other antibiotics are not able to effectively bind to the bacteria.

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Penicillin Binding Protein 2a MRSA carry a unique protein called

PBP 2a (penicillin-binding protein) on the cell membrane that plays a key role in helping to defend against antibiotics.

Sspecific components of the bacterial cell wall interact with PBP 2a to form a chemical barricade.

New antibiotics will deactivate the protein so they succumb to the antibiotic.

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CA-MRSA and HA-MRSA

CA-MRSA Community-acquired Methicillin resistant Staph aureus Unique microbiologic and genetic

properties compared with HA-MRSA may allow the community strains to spread more easily or cause more skin disease

HA-MRSA Healthcare-acquired Methicillin resistant Staph aureus

Many hospitals now seeing CA-MRSA in healthcare associated infections

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Differences in Strains

HA-MRSA Pulse field gel

electrophoresis (PFGE) USA 100, 200 & 500

Less mobile Panton valentine leucocidin

(PVL) gene rare More resistant to antibiotics

CA-MRSA Pulse field gel electrophoresis

(PFGE) USA 300, 400, 1000 &1100

More mobile PVL gene more common

Less resistant to abx Clindamycin resistance

developing in USA 300 strains

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Community-acquired (CA)-MRSA

Susceptible to Clindamycin, Tetracyclines, and Bactrim

Genotypes of CA-MRSAmost common in US is clonal cluster ST-8

classified by the CDC as "USA 300." CA-MRSA has a novel methicillin-resistance

cassette element: type SCC mec IV, which has not been found in HA-MRSA isolates

CA-MRSA is more likely to encode for the Panton-Valentine leukocidin (PVL) toxinvirulence factor associated with severe necrotizing

pneumonia and skin and soft-tissue infections.

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Severe CA-MRSA – Not PVL Most scientists believed the cause of severe

CA-MRSA infection was Panton-Valentine leukocidin (PVL) toxin released by the organism

However, a study indicating that PVL does not play a major role in CA- MRSA infections was published in 2006

Question: what does????

Reference: J Voyich et al. Is Panton-Valentine leukocidin the major virulence determinant in community-associated methicillin-resistant Staphylococcus aureus disease? The Journal of Infectious Diseases 194(12), 2006

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Phenol Soluble Modulin Protein

Newly described proteins in CA-MRSAmembers of the phenol-soluble

modulin (PSM) protein family CA-MRSA strains attract and then destroy

protective human white blood cellseliminates immune defense

mechanisms production of the protein was

typically higher in CA-MRSA strains○ Release Panton Valentine Leukocidin

virulence toxin to destroy tissue

Identification of novel cytolytic peptides as key virulence determinants of community-associated MRSA. Wang, Otto et al.Nature Medicine 2007 Nov 11 epub.

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Vancomycin Resistance

In 1996, the first clinical isolate - Japan In June 2002, Vancomycin Resistant Staph

aureus (VRSA) isolated from a intravenous catheter site Michigan resident aged 40 years with

diabetes, peripheral vascular disease, and chronic renal failure

It contained the Van A resistance gene – from VRE

vanA in this VRSA - acquired through exchange of genetic material from the vancomycin-resistant enterococcus also isolated from the swab culture

MMWR July 5, 2002 / 51(26);565-567

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New, lethal MRSA strain emerges……

A new strain of methicillin-resistant Staphylococcus aureus (MRSA) is emerging

Researchers with Henry Ford Hospital say the USA600 strain is partially immune to vancomycin

Half of the USA600-infected patients in the study died within a month, a death rate five times that of those infected with known MRSA strains. (Ordinarily, 11 percent of patients infected with MRSA die within 30 days)

Factor may be age - those with the strain were, on average, 64 years old, as compared with 52 years old for other MRSA-infected people.

Source: Presentation at the Infectious Diseases Society of America, October 29, 2009

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Populations at Risk for CA-MRSA

CA-MRSA do not have the usual risk factors associated with nosocomial MRSA.

Populations at greater risk include: children and day care centers persons in correctional facilities military personnel native populations gay men HIV-infected persons Sports: football, basketball, baseball,

wrestlers, fencing, soccer injection drug users homeless

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Pets can carry MRSA

German woman - multiple deep abscesses Strain of drug-resistant MRSA Cured after the family's cat was tested and treated.

Husband and two children carriers of MRSA Treated and tested negative, she still was infected Three apparently healthy cats screened One tested positive for MRSA 4 weeks after the cat was treated with antibiotics,

the woman was also free of MRSA "We conclude that pets should be considered as

possible household reservoirs of MRSA that can cause infection or reinfection in humans”.

Source: March 13 2007, New England Journal of Medicine

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MRSA Skin/Soft Tissue

NEJM – August 17, 2006 Emergency departments in 11 university-

affiliated August 2004 Researchers enrolled adult patients with

acute, purulent skin and soft-tissue infections MRSA found to be the most common

causative agent S. aureus was isolated from 320 of 422

patients (76%) with skin and soft-tissue infections, with the prevalence of MRSA being 59% overall.

MRSA coverage when antimicrobial therapy is needed for the treatment of skin and soft-tissue infections

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Risk Factors for Acquiring HA-MRSA

Break in natural skin barrier:Surgery – especially implantsBedsores

Invasive devices and proceduresIntravenous cathetersUrinary cathetersIntubation

Overuse of antibiotics Patients with co-morbidities

obesity, diabetes, steroids

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Hospital EquipmentContaminated

shared equipment Contaminated hands

of healthcare workers – especially if presence of contact dermatitis and other skin conditions

Contaminated environment

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Staph aureus Colonization Colonization: Staph bacteria are

present on or in the body without causing illness.

Approximately 25 to 30% of the population is colonized in the nose with sensitive Staph aureus at a given timeNEBH is finding 23% are colonized

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MRSA Colonization ~2-10% general population

colonized with MRSANEBH is finding 5% are colonized

~0.9%-13.2% healthcare workers are colonized with MRSA

Higher rates in prison (~10%), among drug users, day care centers, professional sports teams and high schools

Once colonized for more than three months, it becomes much more difficult to clear

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Rate of MRSA and MSSA in Surgeons and Residents

Schwarzkopf, et al: MRSA and MSSA in nares of physicians at the Hospital for Joint Diseases in New York. Ran Schwarzkopf, Richelle C. Takemoto, Igor Immerman, James D. Slover, and Joseph A. Bosco Prevalence of

Staphylococcus aureus Colonization in Orthopaedic Surgeons and Their Patients: A Prospective Cohort Controlled Study J Bone Joint Surg Am. 2010;92:1815-1819

74 surgeons and 61 residents screened

Surgeons: MRSA 2.7% and MSSA 23.3%

Residents: MRSA 0% and MSSA 59%

Control Group of Patients: MRSA 2.17% and MSSA 35.7%

Previous studies - 3% of MRSA outbreaks are caused by asymptomatic colonized health-care workers.

Vonberg RP, Stamm-Balderjahn S, Hansen S, Zuschneid I, Ruden H, Behnke M, Gastmeier P. How often do asymptomatic healthcare workers cause methicillin-resistant Staphylococcus aureus outbreaks? A systematic evaluation. Infect Control Hosp Epidemiol. 2006;27:1123-7

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Higher Rate of Infection

if Colonized Colonized patients have a 30-60% risk of

infection following colonization. Host factors influence the onset of

infection.Immunosuppression, steroids, diabetes,

invasive devices and procedures, surgery, skin breakdown, pneumonia, obesity, hematoma, etc.

Reference: Graham P, Lin S, Larson E (2006). "A U.S. population-based survey

of Staphylococcus aureus colonization". Ann Intern Med 144 (5): 318-25.

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Antimicrobial Agents for Treating MRSA

Systemic/PO Topical Decolonization

Vancomycin Chlorhexidine body was

Clindamycin 2% Mupirocin ointment

Bactrim (Bactroban)

Rifampin po

Zyvox (Linezolid)IV or po

Daptomycin

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New Antibiotics for MRSA ETX1153 (e-Therapeutics plc) found to be

highly potent against the most common epidemic strain of MRSA in the UK (EMRSA-16) and effective against V.I.S.A. strains

Platensimycin (Merck) blocks the enzymes that produce fatty acids - essential for the construction of the membranes of bacteria – still under investigation

Daptomycin (Cubist) can be used in combination regimens when infection with a gram-negative or anaerobic organism is either suspected or confirmed. This drug's action is rapidly bactericidal.

Linezolid (Zyvox) is active against gram-positive organisms, such as VRE and MRSA

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MRSA Transmission

MRSA is transmitted by:

Direct Contact with body fluids, skin, secretions, excretions – during patient care and procedures, during sports, in close quarters

Indirect contact by contaminated inanimate objects – such as BP cuffs, oximeter sensors, thermometers, environment, contaminated hands, stethoscopes, otoscopes, commodes, bedside curtains, towels, locker rooms, prisons, toys in daycare

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Outbreaks in Sports Teams An outbreak of methicillin resistant

Staphylococcus aureus infection in a rugby football team. British Journal of Sports Medicine, Vol 32, Issue 2 153-154, 1998

Methicillin-Resistant Staphylococcus aureus in a High School Wrestling Team and the Surrounding Community Arch Intern Med. 1998;158:895-899.

Cutaneous Community-acquired Methicillin-resistant Staphylococcus aureus Infection in Participants of Athletic Activities. Southern Medical Journal. 98(6):596-602, June 2005.

National Athletic Trainers' Association, Inc.Outbreak of Community-Acquired Methicillin-Resistant Staphylococcus aureus Skin Infections Among a Collegiate Football Team. J Athl Train. 2006; 41(2): 141–145.

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CA-MRSA in Sports Teams

Washington Redskins Toronto Blue Jays San Francisco Giants Celtics Basketball Miami Dolphins Dutch Soccer Team Many high school football

teams

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Sources for Transmission Hands number one! Close contact sports Cuts, abrasions and

bruises – wound care Bandages, soiled towels Locker rooms, Jacuzzi, hot

tub Benches, chairs, exercise

equipment Sharing items: towels,

razors, drinks, weights, bikes, etc.

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Prevention: Wash and SanitizeAlcohol Foam, Liquid and Hand Wipes

At NEBH all patients admitted receive package of alcohol wipes

In each patient room, outside rooms, cafeteria and other areas

Wash hands often – before eating, before leaving work, after contamination, after bathroom

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MRSA Patient Rooms Brigham and Women’s Hospital - environmental

contamination and the accompanying relative odds of infection acquisition.

Newly-admitted patients housed in a room in which the most recent occupant was MRSA-positive or VRE-positive, “significantly increased the odds of acquisition” for a MRSA-related or VRE-related infection.

MRSA room 3.9 percent of new patients acquired an infection.

VRE room 4.5 percent acquired a VRE infection.

Huang SS, Datta R, Platt R. Risk of acquiring antibiotic-resistant bacteria from prior room occupants. Arch Intern Med. 2006 Oct 9;166(18):1945-51.

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MRSA contamination in precaution rooms

Ref: Boyce, Infec Cont Hosp Epid 197770% of rooms had environmental contamination when the patient was colonized or infected 42% of nurses’ gloves cultured were contaminated after touching environmental surfaces WITHOUT touching the patient!

Ref: Boyce, et. Al. SHEA 1998 AbstractResults: 14 (40%) of 35 HCWs gowns were culture + for MRSA on exiting room. Clothing underneath was negative. 11 (69%) of 16 HCWs wearing freshly laundered lab coats had detectable contamination. 3 of 11 developed positive hand cx after touching the coat.

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Institutional Prescreening for Detection and Eradication of Methicillin-Resistant Staphylococcus aureus in Patients Undergoing Elective Orthopaedic Surgery J Bone Joint Surg Am. 2010;92:1820-1826David H. Kim, Maureen Spencer, Susan M. Davidson, Ling Li, Jeremy D. Shaw, Diane Gulczynski, David J. Hunter, Juli F. Martha, Gerald B. Miley, Stephen J. Parazin, Pamela Dejoie, and John C. Richmond

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February 2006 Anonymous Nares Cultures

133 patients Obtained nasal culturesPurpose: to determine pre-opMRSA and MSSA colonization

Results:38 – Staph aureus (29%)

*5 - MRSA ( 4%)*all undiagnosed and no precautions used in OR or postop nursing unit

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Decolonization Treatment Protocol

•5-day application of intranasal 2% mupirocin - applied twice daily - for MRSA and Staph aureus positive patients.

•Daily body wash with chlorhexidine

•MRSA Patients - Vancomycin surgical prophylaxis

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What were the outcomes?

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MRSA/MSSA Eradication Results

From July 17, 2006 through July 2010

25,025 patients screened○ 5770 (23%) positive for Staph aureus ○ 1027 ( 4%) positive for MRSA

○ Repeat nasal screens on MRSA patients revealed 78% eradication

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Time Period Inpatient surgeries # Surgical Infections % MRSA/MSSA

FY06 10/01/05-07/16/06 5293* 24 0.45%

FY0707/17/06-09/30/07 7019 6 0.08%

FY08 10/01/07-09/30/08 6323 7 0.11%

FY09 10/01/08-09/30/09 6364 11 0.17%

FY10 10/01/10-07/31/10 5397 5 0.09%

*historical controls

% MRSA and Staph aureus SSI

In Conclusion MRSA is increasing in the community and in

hospitals Overuse of antibiotics has created some of the

problem Resistance among the species is a factor in

resistance Close quarters, equipment, environments and

contaminated hands are sources for transmission Limited antibiotics available to treat MRSA Pre-surgical screening program is an effective

method of detection for treatment and precautions

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