Diagnosis and Treatment of Methicillin-resistant Staphylococcus aureus (MRSA)

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Diagnosis and Treatment of Methicillin-resistant
Staphylococcus aureus (MRSA)
John G. Bartlett, MD Professor of Medicine Johns
Hopkins University School of Medicine
The International AIDS SocietyUSA
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Slide 3
From J. G. Bartlett, MD, at 11th RW Program
Clinical Update, IASUSA.
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METHICILLIN-RESISTANT S. AUREUS INFECTIONS AMONG
PATIENTS IN THE EMERGENCY DEPARTMENTS(Moran GJ.
NEJM 200635566)

• GOAL Determine the prevalence of MRSA as cause
  of skin and soft tissue infections in multiple
  communities
• METHOD
• 1) EMERGEncy ID Net 11 sites
• 2) gt 18 yrs, lesion lt1 wk, Aug 2004
• 3) S. aureus isolates CDC

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• TREATMENT
• ? I D antibiotic 60
• ? I D only 19
• Betalactam 198/311 (64)
• MRSA 100/175 (57)
• Outcome at 15-21 days
• ? Resolved in 96
• ? No correlation with MRSA or treatment with
  active abx
• Contact similar lesion 18

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STAPH AUREUS (USA 300 400)NEW SYNDROMES

• Necrotizing skin infections
• (Spider bite abscesses)
• Necrotizing pneumonia
• Necrotizing fasciitis
• Septic thrombophlebitis
• Pelvic syndromes (Peds) Septic
• arthritis hips, pelvic abscess
• Waterhouse Friderichsen syndrome

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CONCLUSIONS

• MRSA epidemic in the community
• Differed from nosocomial MRSA
• Diverse and often unique pathology

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Slide 9
From J. G. Bartlett, MD, at 11th RW Program
Clinical Update, IASUSA.
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PFGE TYPING OF MRSA

• HA HCA CA TOTAL
• USA 100 74 62 23 58
• USA 300 16 22 67 29

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PROJECTIONS AND CONCLUSIONS

• US burden invasive
• MRSA infections 94,360/yr
• Mortality 18,650/yr
• Incidence 32/100,000
• S. pneumonia-----14/100.000
• Regional differences
• Portland--------------20/100,000
• Baltimore------------118/100,00

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MRSA TREATMENT

• Work horse Vancomycin
• Use 16 tons/year
• Resistance 6 strains in 50 years !!!
• But (Tenover, CID)
• Heteroresistance
• MIC creep
• Persistant bactermia
• Nephrotoxicity

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TREATMENT OF SERIOUS MRSA INFECTIONS VANCOMYCIN

• Standard 1 gm IV or 15-22 mg/kg Q 12 hr
• Trough goal mcg/mL
• MRSA pneumonia 15-20
• CNS infection 20
• Endocarditis 10-20
• Bacteremia 10-15

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VANCOMYCIN FAILURES

• Linezolid 600 mg Q 12 h
• Daptomycin 6-10 mg/kg/d
• Clindamycin 600 mg Q 8 h
• Trimethoprim sulfa 10/50
• mg/kg/d rifampin 30 mg/kg/d

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ANTIBIOTICS FOR MRSA
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EPIDEMIOLOGY

• Source Nose, skin, objects
• Nose MSSA 30
• MRSA 2-5
• St. Louis Rams Objects
• MSM Genital source
• (CID 200744410)
• Intervention Barrier precautions
• Nose Muperocin
• Body Hebiclens, Phisohex

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MRSA (USA 300) in MSM (Diep BA. Ann Intern Med
2008148249)

• Method 9 hospital survey in SF for MRSA
  infections 2004-06
• Results Analysis of 532/2495 cases
• MSM risk RR 13.2
• Sites Buttocks, genitals, perineum
• Unrelated to HIV

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UNIVERSAL SURVEILANCE FOR MRSA IN 3 AFFILIATED
HOSPITALS (Robicsek A et al. Ann Intern Medicine
2008148409)

• Goal To determine the effect of two expanded
  surveillance methods on rates of MRSA infection

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RESULTS

• Prevalence of MRSA 3,926/73,464 (8.3)
• Aggregate MRSA infections
• Study period Rate Compared
• (/10,000 pt d) baseline
• Control 8.9 -----
• ICU 7.4 -- 36
• Universal 3.9 -- 70

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MRSA CONCLUSIONS

• S. aureus ? MRSA
• Incredibly diverse pathogenic resistance
  mechanisms
• Major bacterial pathogen of 21st century (so far)
• Epidemiology Human-human
• Management
• Abscesses Drain
• Vancomycin, etc.
• Epidemiology barrier
• History If controlled, it will return