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Surgical infection and outbreaks

Surgical infection and outbreaks. Malcolm Richardson PhD, FSB, FRCPath Regional Mycology Reference Centre University Hospital of South Manchester, and The University of Manchester. Nosocomial Due to break in, or contamination of hospital water system Due to break in HEPA filtration system

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Surgical infection and outbreaks

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  1. Surgical infection and outbreaks Malcolm Richardson PhD, FSB, FRCPath Regional Mycology Reference Centre University Hospital of South Manchester, and The University of Manchester

  2. Nosocomial Due to break in, or contamination of hospital water system Due to break in HEPA filtration system Due to construction or demolition work in the hospital Community-acquired Due to occupational activities Due to leisure activities Due to exposure to Aspergillus spores (minimum effective dose not known) Nosocomially vs. community-acquired IA Praz-Christinaz et al. Transplant Infect Dis 2007; 9: 175-181

  3. 53 outbreaks: 1967-2005 • 458 affected patients: • 299 (65.3%) haematological malignancies • Route of transmission: air • Site of primary infection: lower respiratory tract (356 patients) • Surgical site infections (24 patients) • Skin infections (24 patients)

  4. Nosocomial aspergillosis

  5. Outbreaks update 2009Weber et al. Medical Mycology 2009 • >60 English literature

  6. Species distrubution

  7. Infection sites • Pulmonary • Post-operative • Cardiac surgery • Ophthalmic surgery • Dental surgery • Cutaneous

  8. Post-operative aspergillosis • Dd paper • >500 cases • Cardiac surgery (n = 188 • Ophthalmic surgery (n > 90) • Dental surgery (n = 100) • Wound infection (n = 22) • Bronchial infections (n = 30) • Orthopedic surgery (n = 42) • Vascular prosthetic surgery (n = 22) • Neurosurgery (n = 25) • Source presumed to be airborne infection

  9. 2010 • 20 healthy individuals • Conventional and molecular analysis • 74 culturable genera • 11 non-culturable • Aspergillus species: 35%

  10. Liver transplant recipient • 11-days post-transplant: Aspergillus fumigatus deep-surgical site infection • 2 patients: transplantation unit: pulmonary aspergillosis • Debridement and changing of dressings: bioaerosols • CID 2002

  11. Events in the growth of Aspergillus

  12. Aw < 0.80, ERH <80% Aw < 0.80-0.90, ERH <80-90% Aw >0.90, ERH >90% water Aw: Minimum water activity level at 25°C ERH: Equilibrium relative humidity

  13. Air as a source of human infection • Inhalation: most common portal of entry • Temporal association between hospital-based outbreaks and construction • Very little data on base-line concentrations • Longitudinal studies show no correlation between sporadic cases of IA and changes in spore count

  14. Concentrations of airborne Aspergillus compared to the incidence of invasive aspergillosis: lack of correlation • 54-week air sampling period • A. fumigatus and A. flavus: mean 1.83 cfu m-3 • Individual samples: maximum: 11.6 cfu m-3 • No correlation with season or ward • 6 cases of IPA during sampling period • No association with fluctuations in air count Conclusion: “the available data do not provide a firm link between hospital exposure and an increased incidence of aspergillosis” Hospenthal et al., Medical Mycology 1998.

  15. Heavy excavation!

  16. Ventilation as a source

  17. Source of Aspergillus in the operating theatre

  18. Surgical infection

  19. A thermal ceiling as source of Aspergillus

  20. Dust: a perfect home for Aspergillus! GM

  21. Dust collection

  22. Air sampling: SAS Super 100 and Duo

  23. Acceptable levels • HEPA filtered air: 0 • Open ward:? • General hospital areas: ? • Outdoor air: highly variable/seasonal

  24. Efficacy of prevention by HEPA filtration or laminar airflow against Aspergillus airborne contamination during hospital renovation • Conclusions: • strong association between building renovation and an increase in environmental contamination • confirmation of the high efficacy of laminar airflow plus HEPA filtration and a high air-exchange rate • HEPA filtration alone did not prevent contamination during renovation • ”A standard protocol for aerobiological surveillance is needed” Cornet et al. Infect Control Hosp Epidemiol 1999; 20: 508-513.

  25. Invasive aspergillosis related to construction and the utility of air sampling • 8-bedded BMT unit • 2 cases of IPA • 5 cases of colonisation • Coincided with major construction project on floor directly below unit • High air counts before cleaning • No isolation after construction stopped and deep cleaning Lai et al., 39th ICAAC, San Francisco 1999

  26. Is air sampling necessary, if so, when? • Determination of source: outbreaks • occupants have symptoms, but no obvious building damage • contamination suspected through air from other parts of the building

  27. Malt extract agar Heptane Undecane Isoprene 2,4 Hexadiene 2-Methyl-1,3-pentadiene 1,3-Octadiene 2-Methyl-1-butanol 3-Methyl-1-butanol 2-Ethyl-1-hexanol Wood Methylpyrazine Acetone 2-Pentanon 2-Hexanone 2-Heptanone 4-Heptanone 2-Octanone 3-Octanone Acetophenone -Farnesene Aspergillus fumigatus Head-space solid-phase microextraction Fiedler et al. 2001 Int J Hyg Environ Health

  28. 7-year sampling period: weekly: 978 samples • Aspergillus spp. 16.7%: 1.8 cfu/m3 - 28.3 cfu/m3 • 45 cases proven IA (2.29% allo; 0.36% auto HSCT) • cases of IA analysed 14 and 28-days following high counts • Conclusion: high counts did not predict risk of developing IA • Rupp et al. JHI 2008.

  29. Particle counting Hansen et al. JHI 2008; 70: 259-264.

  30. Particle counting • IQAir Particle Scan Pro Airborne Laser Counter • 0.3m - 5m

  31. during demolition building was sealed and water sprayed to minimise dust emission • particle and fungal concentrations monitored before and during demolition • particle concentrations significantly higher during demolition • no difference in moulds cultured at 370C before and during demolition

  32. Air quality monitoring of HEPA-filtered hospital rooms by particulate counting Anttila V-J, Nihtinen A, Kuutamo T, Richardson M. 2008.

  33. Air quality monitoring of HEPA-filtered hospital rooms by particulate counting Anttila V-J, Nihtinen A, Kuutamo T, Richardson M. 2008.

  34. Construction of an outbreak curve • Line listing of all infected patients • Evaluation of air ventilation system • Regular particle counting • Water damage/ingress assessment • Possible common source exposure • Air sampling • Water analysis • Settled dust analysis

  35. AirInSpace: Immunair 540-640 m3/hr rapid air decontamination not sensitive to exterior movement <1 cfu/m3 Am J Infect Control 2007; 35: 460-466.

  36. Conclusions • Overall mortality among patients involved in outbreaks: 50-60% • Recent outbreaks due to internal construction or renovation with failure to control spread of contaminated dust • Key interventions: surveillance and engineering controls • Minimum effective dose of Aspergillus conidia is not known

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