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Microbial Contaminate of Heater-Cooler Units: M. Chimaera and Beyond

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Presentation given at APIC 2017 in Oregon by Jack Rihs.

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Microbial Contaminate of Heater-Cooler Units: M. Chimaera and Beyond

  1. 1. MICROBIAL CONTAMINATION OF HEATER-COOLER UNITS M. chimaera and Beyond
  2. 2. Objective • Determine percent positivity of non-tuberculosis mycobacterium, primarily M. chimaera in heater-cooler units (HCU) • Assess colonization of heater-cooler units before and after disinfection
  3. 3. Mycobacterium chimaera • M. chimaera is a slow growing non-tuberculosis mycobacterium • More than 175 species, referred to as NTMs • These bacteria can be found in the soil and water, including potable water • Opportunistic, rarely causes infections in humans • M. chimaera is a relatively new species (2004) • M. chimaera has been linked to infections associated with heater-cooler units
  4. 4. M. chimaera Infections Associated with HCUs • July 2014, Federal Office of Public Health Switzerland issues warning • March 2015, Hugo Sax et al. Clinical Infectious Diseases, first causal evidence to link cases of cardiovascular infections to heater-coolers • June 2015, heater-cooler manufacturer issues Field Safety Notice • September 2015, FDA inspectors visit manufacturer facilities in Germany
  5. 5. M. chimaera Infections Associated with HCDs • In October 2015, a Pennsylvania hospital reported eight patients with M. chimaera infections following cardiac surgery • October 2015, FDA and CDC issue safety communications • December 2015, FDA blocks entry of these units • April 2016, M. chimaera contamination confirmed at the manufacturing site
  6. 6. Heater-Cooler Unit
  7. 7. Heater-Cooler Circuits
  8. 8. What Do We Know About These Infections • Cases of cardiovascular infections have been reported as far back as 2008 • Most of these have occurred in Switzerland, Germany, the Netherlands and the UK • Most infections have been prosthetic valve infections or coronary artery bypass grafts • Difficult to treat, approaching 50% mortality • Patients who had surgery before Sept 2014 may have been at greater risk • Risk for infection is low
  9. 9. Manufacturer Recommended Testing • Heterotrophic Plate Count (HPC) less than 500 cfu/ml • Pseudomonas aeruginosa not detectable in 100 ml • Coliform bacteria not detected in 100 ml • Non-tuberculosis mycobacterium not detected in 100 ml
  10. 10. Laboratory Methods • Performed with standard laboratory methods  Heterotrophic Plate Count (HPC)  Pseudomonas aeruginosa  Coliform bacteria • Non-tuberculosis Mycobacterium  Filter concentration and decontamination with 0.2 M KCl-HCl, pH 2.2  Cultivation: Middlebrook 7H10 and Mitchison 7H11  Incubation at 30°C for 6 weeks  Identification by 16S DNA sequencing
  11. 11. Heater-Cooler Culture Results • Samples from 23 different institutions across 14 states, the District of Columbia, and Canada • 89 different heater-cooler units were tested, 33 of these tested positive for M. chimaera (37%) • Our results show extensive colonization of M. chimaera
  12. 12. Heater-Cooler Culture Results • Four units tested positive with three different species of Mycobacterium • 19 units had two different Mycobacterium species recovered • M. gordonae was isolated 26 of 89 (29%), second most frequently isolated NTM
  13. 13. Heater-Cooler Culture Results • Some units remained positive for Mycobacteria for months • Other units appeared negative but later M. chimaera was detected in low numbers
  14. 14. Other NTM Recovered • M. cookie • M. palustre • M. gordonae • M. timonense • M. nebraskense • M. chlorophenolicum (rapid grower) • M. abscessus/chelonae (rapid grower)
  15. 15. M. chimaera Culture M. chimaera
  16. 16. Colonies Look Yellow after Several Weeks
  17. 17. Aging Colonies
  18. 18. M. abscessus/chelonae and M. gordonae
  19. 19. Heterotrophic Plate Count • Results ranged from <1 cfu/ml to >106 cfu/ml • HPC can be used as a quick test to use to monitor disinfection procedures • HPC results cannot predict the presence of NTM
  20. 20. Uninterpretable • 97 of 653 water samples were uninterpretable due to heavy bacterial or fungal overgrowth (15%)
  21. 21. Uninterpretable • Although we did not culture for fungi, it was present in many samples
  22. 22. Limited Test Results • Zero of 74 HCUs tested positive for coliforms • One of 72 HCUs were positive for Pseudomonas aeruginosa • Four of 22 HCUs were positive for Legionella
  23. 23. Conclusions • M.chimaera contamination was extensive • Heater-cooler units were contaminated with other NTM as well as fungi • Colonization persisted after disinfection • Monitoring for fungi and Legionella is advisable
  24. 24. Infection Control Practitioners Should • Establish regular cleaning, disinfection and maintenance schedules • Monitor and document cleaning, disinfection and maintenance • Provide written instructions on how to collect samples • Follow the culture results • Monitor used and new instruments • Consider risk of infection from any and all heater-cooler units
  25. 25. THANK YOU John Rihs VP Laboratory Services jrihs@specialpathogenslab.com

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