627. A Cluster of Mycobacterium abscessus among Lung Transplant Patients: Investigation and Mitigation
Session: Oral Abstract Session: Epidemiology of Transplant Infections
Thursday, October 8, 2015: 2:15 PM
Room: 25--ABC

Background: We investigated an outbreak of Mycobacterium abscessus among lung transplant patients in 2013-2014 at a single tertiary care hospital.

Methods: We performed an epidemiological study of all patients with positive cultures for M. abscessus from January 2013 through March 2015. We also performed cultures of biofilms obtained from hospital water outlets. Clinical and environmental isolates of M. abscessus were typed using erm and rpoβ genes, as well as pulsed-field gel electrophoresis (PFGE).

Results: Incident cases of M. abscessus were detected in 39 recently hospitalized lung transplant patients during the outbreak period of August 2013 through May 2014 (Figure). In 36 (92%) of these cases, M. abscessus was first isolated from the respiratory tract. Cultures of environmental biofilms from 12 (16%) of 73 water sources, including patient room faucets and shower heads, ward faucets, and ice machines grew M. abscessus.

A unique genotypic profile, consisting of a type VI erm gene and C-->T mutation at base pair 207 of the rpoβ gene, was identified in 10 (77%) of 13 clinical isolates analyzed and in all 12 environmental isolates.  Four of these 10 clinical isolates and eight of the 12 environmental isolates were analyzed by PFGE, and all isolates were indistinguishable. 

We instituted a sterile water protocol for hospitalized lung transplant patients in June 2014, eliminating ice and tap water use for oral care, gastric/nasogastric tube flushes, speech therapy evaluation, consumption, and bathing. In July 2014, the antibiotic prophylaxis regimen for lung transplant surgeries was changed to include imipenem and inhaled amikacin.  The incidence rate of M. abscessus decreased from 3.9 cases per month during the outbreak period (8/2013-5/2014) to 1.0 cases per month during the intervention period (6/2014-3/2015) (incidence rate ratio, 0.26; 95% confidence interval, 0.13-0.51; P<0.0001), approximating the pre-outbreak incidence rate.

Conclusion: An outbreak of clonally-related pulmonary M. abscessus among lung transplant patients was epidemiologically linked to water sources. The incidence rate returned to baseline after institution of a sterile water protocol and change in perioperative antibiotic prophylaxis.

 

 

 

 

 

 

 

 

Arthur W. Baker, MD, MPH1,2, Sarah S. Lewis, MD MPH1,2, Barbara D. Alexander, MD, MHS, FIDSA1, Pamela J. Isaacs, BSN, MHA, CIC3, Lisa C. Pickett, MD3, Richard J. Wallace Jr., MD4, Barbara A. Brown-Elliott, MS, MT(ASCP)SM4, Nancy Strittholt, RN, BSN, CIC3, Kevin C. Hazen, PhD, FIDSA3, Cameron R. Wolfe, MBBS (Hons), MPH1, Eileen K. Maziarz, MD1, Jennifer Horan Saullo, MD, PharmD1, Robert D. Davis, MD5, John M. Reynolds, MD6, Deverick Anderson, MD, MPH, FIDSA, FSHEA1,2, Daniel J. Sexton, MD, FIDSA, FSHEA1,2 and Luke F. Chen, MBBS, MPH, CIC, FRACP1,2, (1)Division of Infectious Diseases, Duke University Medical Center, Durham, NC, (2)Duke Infection Control Outreach Network, Durham, NC, (3)Duke University Medical Center, Durham, NC, (4)University of Texas Health Science Center, Tyler, TX, (5)Division of Cardiovascular and Thoracic Surgery, Duke University Medical Center, Durham, NC, (6)Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, NC

Disclosures:

A. W. Baker, None

S. S. Lewis, None

B. D. Alexander, None

P. J. Isaacs, None

L. C. Pickett, None

R. J. Wallace Jr., None

B. A. Brown-Elliott, None

N. Strittholt, None

K. C. Hazen, None

C. R. Wolfe, None

E. K. Maziarz, None

J. H. Saullo, None

R. D. Davis, None

J. M. Reynolds, None

D. Anderson, None

D. J. Sexton, None

L. F. Chen, None

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