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Community Associated Resistant Bacteria:What Bugs and What Drugs Work Against Them?

Community Associated Resistant Bacteria:What Bugs and What Drugs Work Against Them?. Lilly Immergluck, MD Associate Professor of Pediatrics Divisions of General Pediatrics and Pediatric Infectious Diseases Morehouse School of Medicine March 1, 2006. Background Information.

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Community Associated Resistant Bacteria:What Bugs and What Drugs Work Against Them?

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  1. Community Associated Resistant Bacteria:What Bugs and What Drugs Work Against Them? Lilly Immergluck, MD Associate Professor of Pediatrics Divisions of General Pediatrics and Pediatric Infectious Diseases Morehouse School of Medicine March 1, 2006

  2. Background Information

  3. Resistant Bacteria Mutations XX Resistance Gene Transfer New Resistant Bacteria Campaign to Prevent Antimicrobial Resistance in Healthcare Settings Emergence of Antimicrobial Resistance Susceptible Bacteria

  4. Campaign to Prevent Antimicrobial Resistance in Healthcare Settings Resistant StrainsRare Antimicrobial Exposure Resistant Strains Dominant x x x x x x x x x x x x Selection for antimicrobial-resistant Strains

  5. What “Bugs” are we talking about…in Pediatrics? • Community-associated Methicillin Resistant Staphylococcus aureus • Drug Resistant Streptococcus pneumoniae

  6. Methicillin Resistant Staphylococcus aureus

  7. Lowy, Frank,Staphylococcus Infections. NEJM. August, 1998

  8. Types of MRSA • BRSA- Borderline MRSA • MRSA- related to mecA gene=ORSA • Hospital associated MRSA • Community associated MRSA

  9. Mechanism of Resistance for MRSA Mec A gene Staph Staph antibiotic

  10. Staphylococcal chromosomal cassette mec IV, type 4(SCC mec type IV) Derensinski S. Clin Infect Dis 2005:562-73

  11. Emergence of USA 300 clone • Result of insertion of SCCmecA type IV • Donor staph isolate is MSSA • Differences from HA-MRSA: • Gene cassette coding for methicillin resistance • Carriage of plasmids encoding resistance to antibiotics of other classes • Associated virulence factor

  12. SCCmec types I-V Derensinski S. Clin Infect Dis 2005:562-73

  13. Staphylococcus sp. • “Isolates of staphylococci that are shown to carry the mecA gene, or that produce PBP2a, the gene product, should be reported as oxacillin resistant”

  14. Epidemiology of MRSA • First described in 1961 • Approximately 50% of Staphylococcus aureus infections in ICU in US due to MRSA

  15. Risk Factors for Hospital acquired MRSA in Adults • Prolonged/recurrent antibiotic exposure • Prolonged hospitalization or ICU • Chronically ill • Nursing home residence • Dialysis or Malignancy

  16. HA-MRSA Prevalence Lowy, Frank,Staphylococcus Infections. NEJM. August, 1998

  17. Definition of Community-associated MRSA Salgado, Farr, Calfee Clin Infect Dis, 2003

  18. Epidemiology of Community acquired MRSA • Case Report in Chicago • Outbreak among high school wrestling team in Vermont • Reports have occurred in Chicago, Minnesota, North Dakota, Dallas, Winnipeg, Toronta, and in Australia

  19. Headlines to catch our attention… • Methicillin-Resistant Staphylococcus aureus Infections Among Competitive Sports Participants --- Colorado, Indiana, Pennsylvania, and Los Angeles County, 2000—2003 • Four Pediatric Deaths from Community-Acquired Methicillin-Resistant Staphylococcus aureus -- Minnesota and North Dakota, 1997-1999

  20. “Study Finds Spread of Resistant Staph” By THE ASSOCIATED PRESS Published: April 7, 2005, NY Times

  21. “PRO FOOTBALL; After Medical Scare, Giants' Center Improves” • November 4, 2004, Thursday • By LYNN ZINSER (NYT); Sports Desk • Late Edition - Final, Section D, Page 4, • “At first, Giants center Shaun O'Hara said he had no idea why his swollen calf was causing so much alarm among team trainers last week. He knew nothing about the staph infections that had struck seven Miami Dolphins last year, hospitalizing two of them, or of…”

  22. Fatal Pediatric Infections from CA-MRSA Source: Centers for Disease Control and Prevention, Atlanta , October 1999 / HOSPITAL INFECTION CONTROL

  23. Minnesota Surveillance Study, 1997 Naimi,LeDell et al Clin Infect Dis 2001

  24. Summary of Age Distribution of CA-MRSA in Minnesota

  25. Clinical Presentation

  26. Maybe as simple as this… courses.washington.edu, accessed from web 2/28/06

  27. Or more severe as this… www.emedicine.com/ped, accessed Feb 28, 2006

  28. MRSA Pneumonia/Empyema

  29. Clinical Presentation of Children with CA-MRSA Herold, Immergluck, et al JAMA 1998

  30. Summary of Risk Factors for CA-MRSA Eady, Cove, Curr Opin Infect Dis, 2003

  31. What Drugs Can Treat This Bug?

  32. “D Test” – positive reaction Inducible clindamycin resistance (erm-mediated) …another example 15 - 26 mm Photos courtesy of J. Jorgensen and K. Fiebelkorn.

  33. “D Test” – negative reaction NO induction (msrA-mediated erythromycin resistance)

  34. MRSA—Erythromycin/Clindamycin Story

  35. Treatment of CA-MRSA • Options are better than hospital acquired-MRSA • Almost all are clindamycin susceptible • Trimethoprim-sulfamethoxazole • Role of quinolones

  36. Profile 1 Clindamcin R Erythromycin R Oxacillin R Penicillin R Vancomycin S Profile 2 Cefazolin S Clindamycin R Erythromycin R Oxacillin R Penicillin R Vancomycin S HA-MRSA susceptibility pattern

  37. Clindamycin Erythromycin Fluoroquinolones Linezolid Rifampin Tetracyclines Trimeth-sulfa Vancomycin CA-MRSA often susceptible to:

  38. Treatment Regimens • Severe infections, multi drug resistant infections • Vancomycin • Daptomycin • Linezolid (pneumonia) • Quinopristin/dalfopristin • Limited infections, less severe • TMP-SMZ • Linezolid • ?No treatment

  39. Data in Atlanta Area • Adult studies • Pediatric studies

  40. Risk Factors for CA-MRSA Colonization in Adults • HIV infection • Lower risk if HIV infected and receiving antibiotics within 3 months before admission • History of skin or soft tissue infection • Hospitalization within preceding year • Receipt of antibiotics within 3 months before admission Hidron, AI, Kourbatova, EV, et al, Clin Infect Dis 2005

  41. Susceptibility of Isolates, by pulsed-field type Hidron, AI, Kourbatova, EV, et al, Clin Infect Dis 2005

  42. Preliminary Data for Atlanta Children 3169 Staphylococcus aureus isolates from 1/2002-12/2004 • 656 (21%) CA-MRSA isolates by phenotype • 485 (15%) HA-MRSA isolates by phenotype • Based on data collected from Egleston and Scottish Rite Hospitals

  43. Proportional S.aureus isolates at Scottish Rite Isolates

  44. Proportional S. aureus isolates at Egleston Isolates

  45. Incidence of SSTI due to S. aureus isolates among Scottish Rite ER Patients, 2002-2004 Isolates/10,000 ER visits

  46. Incident CA-MRSA Isolates from SSTI’s at Egleston and Scottish Rite ER Patients Isolates/10,000 ER visits

  47. Where do we go from here? • Surveillance of children who are colonized with CA-MRSA • Understand risk factors for colonization and subsequent infections due to CA-MRSA • Understand household transmission of CA-MRSA • Develop strategies for eradication of colonization

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