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Reduction of turnaround time for non-tuberculous mycobacteria detection in heater-cooler units by propidium monoazide real-time PCR.

Abstract

BACKGROUND

Invasive non-tuberculous mycobacteria (NTM) infections are emerging worldwide in patients undergoing open-chest cardiac bypass surgery exposed to contaminated heater-cooler units (HCUs). Although this outbreak has been investigated by culturing bacteria isolated from HCU aerosol and water samples, these conventional methods have low-analytic sensitivity, high rates of sample contamination and long turnaround time (TAT).

AIM

To develop a simple and effective method to detect NTM in HCUs by real-time PCR, with a short laboratory TAT and reliable culture results.

METHODS

A total of 281 water samples collected from various HCUs at 7 Italian hospitals were simultaneously screened for NTM by a propidium monoazide (PMA)-PCR assay and by conventional culture testing. The results were analyzed with culture testing being the reference method.

FINDINGS

i) The agreement between culture testing and PMA-PCR was 85.0% with a Ct cut-off value of < 38 vs.80.0% with a Ct of < 43, with a moderate Cohen's kappa coefficient; ii) the Ct cut-off value of < 42 was deemed more suitable for predicting positive specimens; iii) given the low concentration of target DNA in water samples, the minimum volume to be tested was 1 lt.

CONCLUSION

We highly recommend the use of PMA-PCR for fast detection of NTM from environmental samples in order to ascertain whether HCUs may represent a potential source of human exposure to NTM. This reliable and simple method reduces laboratory TAT compared to conventional methods (1-2 days vs. 8 weeks, respectively), thereby improving control strategies and effective management of HCUs.

Authors+Show Affiliations

Department of Public Health and Pediatrics, University of Turin, Italy. Electronic address: savina.ditommaso@unito.it.Department of Public Health and Pediatrics, University of Turin, Italy.Department of Public Health and Pediatrics, University of Turin, Italy.Department of Public Health and Pediatrics, University of Turin, Italy; Microbiology and Virology Unit, University Hospital Citta`della Salute e Della Scienza di Torino, Turin, Italy.Microbiology and Virology Unit, University Hospital Citta`della Salute e Della Scienza di Torino, Turin, Italy.Microbiology and Virology Unit, University Hospital Citta`della Salute e Della Scienza di Torino, Turin, Italy.AOU Città Della Salute e Della Scienza, Torino, Corso Bramante 88/90, 10126 Torino, Italy.Department of Public Health and Pediatrics, University of Turin, Italy.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31628958

Citation

Ditommaso, Savina, et al. "Reduction of Turnaround Time for Non-tuberculous Mycobacteria Detection in Heater-cooler Units By Propidium Monoazide Real-time PCR." The Journal of Hospital Infection, 2019.
Ditommaso S, Giacomuzzi M, Memoli G, et al. Reduction of turnaround time for non-tuberculous mycobacteria detection in heater-cooler units by propidium monoazide real-time PCR. J Hosp Infect. 2019.
Ditommaso, S., Giacomuzzi, M., Memoli, G., Cavallo, R., Curtoni, A., Avolio, M., ... Zotti, C. M. (2019). Reduction of turnaround time for non-tuberculous mycobacteria detection in heater-cooler units by propidium monoazide real-time PCR. The Journal of Hospital Infection, doi:10.1016/j.jhin.2019.10.010.
Ditommaso S, et al. Reduction of Turnaround Time for Non-tuberculous Mycobacteria Detection in Heater-cooler Units By Propidium Monoazide Real-time PCR. J Hosp Infect. 2019 Oct 16; PubMed PMID: 31628958.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Reduction of turnaround time for non-tuberculous mycobacteria detection in heater-cooler units by propidium monoazide real-time PCR. AU - Ditommaso,Savina, AU - Giacomuzzi,Monica, AU - Memoli,Gabriele, AU - Cavallo,Rossana, AU - Curtoni,Antonio, AU - Avolio,Maria, AU - Silvestre,Carlo, AU - Zotti,Carla M, Y1 - 2019/10/16/ PY - 2019/07/02/received PY - 2019/10/08/revised PY - 2019/10/10/accepted PY - 2019/10/20/entrez PY - 2019/10/20/pubmed PY - 2019/10/20/medline KW - PCR KW - cardiac surgery KW - disinfection KW - heater-cooler unit KW - microbiological monitoring KW - mycobacterium chimaera JF - The Journal of hospital infection JO - J. Hosp. Infect. N2 - BACKGROUND: Invasive non-tuberculous mycobacteria (NTM) infections are emerging worldwide in patients undergoing open-chest cardiac bypass surgery exposed to contaminated heater-cooler units (HCUs). Although this outbreak has been investigated by culturing bacteria isolated from HCU aerosol and water samples, these conventional methods have low-analytic sensitivity, high rates of sample contamination and long turnaround time (TAT). AIM: To develop a simple and effective method to detect NTM in HCUs by real-time PCR, with a short laboratory TAT and reliable culture results. METHODS: A total of 281 water samples collected from various HCUs at 7 Italian hospitals were simultaneously screened for NTM by a propidium monoazide (PMA)-PCR assay and by conventional culture testing. The results were analyzed with culture testing being the reference method. FINDINGS: i) The agreement between culture testing and PMA-PCR was 85.0% with a Ct cut-off value of < 38 vs.80.0% with a Ct of < 43, with a moderate Cohen's kappa coefficient; ii) the Ct cut-off value of < 42 was deemed more suitable for predicting positive specimens; iii) given the low concentration of target DNA in water samples, the minimum volume to be tested was 1 lt. CONCLUSION: We highly recommend the use of PMA-PCR for fast detection of NTM from environmental samples in order to ascertain whether HCUs may represent a potential source of human exposure to NTM. This reliable and simple method reduces laboratory TAT compared to conventional methods (1-2 days vs. 8 weeks, respectively), thereby improving control strategies and effective management of HCUs. SN - 1532-2939 UR - https://www.unboundmedicine.com/medline/citation/31628958/Reduction_of_turnaround_time_for_non-tuberculous_mycobacteria_detection_in_heater-cooler_units_by_propidium_monoazide_real-time_PCR L2 - https://linkinghub.elsevier.com/retrieve/pii/S0195-6701(19)30445-1 DB - PRIME DP - Unbound Medicine ER -