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Mercy! MRSA!
Gail R. Hansen, DVM, MPH
State Epidemiologist
Kansas Department of Health and Environment
Healthy Kansans living in safe and sustainable environments.
Before starting, Thanks!
Dr. Dan Hinthorn, KUMC
Ms. Sheri Anderson, KDHE
Healthy Kansans living in safe and sustainable environments.
Staphylococcus aureus
 Gram positive cluster forming

cocci
Sources
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Commonly carried on the skin and
mucus membranes of humans
Most common cause of skin
infections in US
A word about pets
Healthy Kansans living in safe and sustainable environments.
Diseases
 Topical
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Cellulitis
Boils
Impetigo
Wound infections
 Antimicrobials may
not be necessary for
treatment
 Systemic
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Bacteremia
Endocarditis
Toxic Shock
Syndrome
 Require antibiotics
Healthy Kansans living in safe and sustainable environments.
What is MRSA?
 Methicillin-Resistant Staphylococcus
aureus
 Resistant to other beta (ß) lactamaseresistant penicillins and cephalosporins
Healthy Kansans living in safe and sustainable environments.
Staphylococcus aureus perspective
 Staphylococcus has been around as long as history
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Egyptian mummies
1880s--usual cause of pus from wounds
Sulfa drugs reduced infections but resistance developed
Penicillins reduced infections but resistance developed
 Staph has virulence factors & defense mechanisms
that cause rapidly progressive diseases, even with
normal immune systems
Healthy Kansans living in safe and sustainable environments.
Resistance
 Staph have 1 of 5 Staph Cassette
Chromosomes that hold resistance factors
• SCC IV and V are small
CA-MRSA, type IV.
• SCC I-III are large
HA-MRSA types I, II, or III
• The SCCmec A IV (resistance gene to
methicillin) can’t hold all types of resistances
due to size
First described in S. epidermidis in the 1970s
Campaign to Prevent Antimicrobial Resistance in Healthcare Settings
Emergence of Antimicrobial
Resistance Susceptible Bacteria
Resistant Bacteria
Resistance Gene Transfer
New Resistant Bacteria
Campaign to Prevent Antimicrobial Resistance in Healthcare Settings
Selection for antimicrobial-resistant Strains
Resistant Strains
Rare
Antimicrobial
Exposure
Resistant Strains
Dominant
Healthy Kansans living in safe and sustainable environments.
Staph has out-smarted us at
every turn
 Able to make cell walls even though
methicillin should prevent that
 Mortality was 70% before penicillin in 1937
• 1944, with penicillin--mortality 28%
• 1954, with b-lactamase--mortality 50%
• 1962, with methicillin--mortality 30%
 S. aureus is the #1 pathogen in children
Evolution of Antimicrobial Resistance
Penicillin
Methicillin


Penicillin-resistant
Methicillin-resistant
S. aureus
(1950s)
S. aureus
S. aureus (MRSA)
(1960s)
Vancomycin
(1997)
(2002)
Vancomycin intermediate
resistant
S. aureus
Healthy Kansans living in safe and sustainable environments.
PVL and severe disease
 The PVL gene (Panton Valentine
Leukocidin)
• First described in 1894
• Further described by P&L in 1932
• It codes for a cytotoxin against WBC & RBC
• PVL gene is not linked to SCCmec type IV
Found in MSSA and MSSA with PVL
Predated CA-MRSA.
Healthy Kansans living in safe and sustainable environments.
Toxins in staph
 S. aureus may have 30 extracellular products.
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Enzymes, cytotoxins, hemolysins etc
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Acts on cell membranes, forms a pore
 PVL, synergohymenotropic toxin
Leukocytolytic & causes severe tissue damage
Induces granule secretion, release of leukotriene B4, and IL-
8 from WBC.
May cause necrotic skin and lung damage, any age
 SCCmecA typeIV
Grows faster
5X more lethal than CA-MRSA without PVL
Healthy Kansans living in safe and sustainable environments.
Confusing names made easy
 Names are by PFGE, not phage type, ~80/81
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CA-MRSA are called USA-300, USA-500, USA1000, USA-1100.
Most resistant to erythromycin, some clinda resistance.
Most quinolone resistant and 25% resistant to tetras.
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HA-MRSA are called USA-100 USA-200.
Most resistant to erythromycin, clindamycin, quinolones.
Most susceptible to tetra and trimethsulfa.
Healthy Kansans living in safe and sustainable environments.
HA-MRSA
 Scottish study
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Increased new ICU cases of MRSA related to
Nursing staff deficits
Failure to use basic infection control practices
Deficiency of environmental hygiene
 160 sites cultured
Sinks, curtains, bedrails, computers 23% were positive
70% were positive from site where hand contamination
occurred.
 Organisms usually viewed as environmentally
spread
VRE, vancomycin resistant enterococci
CDAD, Cl. difficile associated diarrhea
Healthy Kansans living in safe and sustainable environments.
HA-MRSA Transmission
 Person to person contact most important
• Hands of staff, transiently colonized
 Environment plays a limited role
• Equipment, surfaces
 Droplet-borne transmission is even less
common
Healthy Kansans living in safe and sustainable environments.
Factors that Favor HA-MRSA
Transmission
 High resident to staff ratios
 Lack of attention to basic infection control
measures
 Use of common equipment without
disinfection
 Personal item sharing among residents
 Limited facilities for handwashing
 Inappropriate use of antimicrobials
Healthy Kansans living in safe and sustainable environments.
HA-MRSA Prevention
 Hand hygiene
• Antiseptic washing
• Soap and water
• Waterless handrubs/alcohol
70% better than 95%
Not for visible dirt
• Fake nails
 Beware donor fabrics
Healthy Kansans living in safe and sustainable environments.
CA-MRSA
 MRSA of persons who have not been
hospitalized in the past year
 Usually skin infections in otherwise
healthy people
 Virulence factors allow CA-MRSA to
spread more easily or cause more skin
disease
 25-30% of population colonized with S.
aureus
• 1% (?) with MRSA
Healthy Kansans living in safe and sustainable environments.
CA-MRSA Transmission
 Mostly via contaminated hands
• Contact with infected individuals
• Contact with contaminated environmental
surfaces
 Other risk factors
• Skin-to-skin contact
• Crowded conditions
• Poor hygiene
 Environmental contamination
• Not common
Healthy Kansans living in safe and sustainable environments.
The growth of CA-MRSA
 MRSA reported 2 yr after methicillin was first
used (1961)
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Predecessor to the USA300 strain
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Aborigines in Australia, New Zealand
Native American children in MN, NE, ND
MSM in LA, ATL, Boston
Prisoners, athletes, wrestlers, football, fencers
 MRSA infections started in community 1980’s
 Majority of SSSI in ED across US now have CA
MRSA
most CA-MRSA appear to be resistant to β-lactams only
Healthy Kansans living in safe and sustainable environments.
CA-MRSA Syndromes
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Necrotizing skin infections (spider bites)
Necrotizing fasciitis (“flesh eating” like strep)
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Pyomyositis with eos in Africa, & pyomyositis in HIV.
Septic thrombophlebitis of extremities
Pelvic syndromes especially in children
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Septic arthritis of hips
Pelvic osteomyelitis
Pelvic abscesses
Septic thrombophlebitis
Waterhouse-Friderichson syndrome
Rapidly progressive necrotizing pneumonia
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Develops in hours, even in previously health young people.
Healthy Kansans living in safe and sustainable environments.
CA-MRSA Prevention
 Cover draining infections
• HCW off work until open wounds healed.
 Wash hands
• during day
• after toileting
• before eating
 Don’t share personal items
Healthy Kansans living in safe and sustainable environments.
CA-MRSA Prevention
 Wash linens in hot water
 Dry clothes in hot dryer, not air drying
 Shower after group sports, gym use, sauna,
steam room or tanning
• With draining wounds, no athletic competition
• Clean communal surfaces at gym
 Immunization so far not effective
Healthy Kansans living in safe and sustainable environments.
Spider bite or MRSA?
 Start with an itch, then painful
 Get worse and not better with local
treatment
 Both have central necrosis
• Look blackish or dark red or purple in center
 Surrounding induration and erythema
 Slow to resolve
• Neither Keflex nor Dapsone work
 Did you see the spider?
Photo courtesy of Dr. D. Hinthorn, KUMC
Healthy Kansans living in safe and sustainable environments.
Treatment for MRSA
 Incise and drain abscesses
 Culture, culture, culture!
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Results of susceptibility determine antimicrobials
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Vancomycin
 Antimicrobials
VRSA and VISA
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Trimeth-sulfa
Doxy or minocycline
Clindamycin
Quinolones? No
Healthy Kansans living in safe and sustainable environments.
Surveillance
 Communication between facilities about MRSA +
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patients
Review culture and susceptibility data
Maintain confidential line listing of MRSA +
patients
Flag MRSA+patients to assist with precautions
Active surveillance cultures for MRSA?
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Not be a routine measure
Maybe during an outbreak
Routine culture and treatment in hospitals not effective
in reducing MRSA
Healthy Kansans living in safe and sustainable environments.
Reporting Requirements
 Single cases of MRSA are not reportable in
KS or MO
 Outbreaks are reportable in KS and MO
 Other states different
• VRSA or VISA reportable from any site
• MRSA reportable if isolated from sterile site
• S. aureus reportable if it results in a serious infection
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resulting in death or admission to ICU
MRSA labs reportable only
All MRSA infection reportable
Healthy Kansans living in safe and sustainable environments.
MRSA Outbreaks
 2 or more patients with MRSA infection
that are epidemiologically linked
• Roommates in LTC, cared for by the same
•
staff
2 members of the football team
 Infections have temporal relationship
 Call KDHE-OSE at 877-427-7317
• Report outbreak or request assistance
Questions?
?
?
877-427-7317