Cargando…

A New Culture Method for the Detection of Non-Tuberculous Mycobacteria in Water Samples from Heater–Cooler Units and Extracorporeal Membrane Oxygenation Machines

The isolation of non-tuberculous mycobacteria (NTM) from cultures is particularly laborious due to the potential overgrowth of coexisting non-acid fast bacilli. To reduce the overgrowth of these non-mycobacterial organisms, a decontamination step with NaOH or cetylpyridinium chloride is highly recom...

Descripción completa

Detalles Bibliográficos
Autores principales: Ditommaso, Savina, Giacomuzzi, Monica, Memoli, Gabriele, Garlasco, Jacopo, Curtoni, Antonio, Iannaccone, Marco, Zotti, Carla M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9518321/
https://www.ncbi.nlm.nih.gov/pubmed/36078363
http://dx.doi.org/10.3390/ijerph191710645
_version_ 1784799154311004160
author Ditommaso, Savina
Giacomuzzi, Monica
Memoli, Gabriele
Garlasco, Jacopo
Curtoni, Antonio
Iannaccone, Marco
Zotti, Carla M.
author_facet Ditommaso, Savina
Giacomuzzi, Monica
Memoli, Gabriele
Garlasco, Jacopo
Curtoni, Antonio
Iannaccone, Marco
Zotti, Carla M.
author_sort Ditommaso, Savina
collection PubMed
description The isolation of non-tuberculous mycobacteria (NTM) from cultures is particularly laborious due to the potential overgrowth of coexisting non-acid fast bacilli. To reduce the overgrowth of these non-mycobacterial organisms, a decontamination step with NaOH or cetylpyridinium chloride is highly recommended before plating the samples on the culture medium. However, due to their toxicity, decontamination solutions tend to decrease NTM recovery from clinical and environmental samples. Here, we tested an alternative method for NTM recovery based on the use of NTM Elite agar, a selective medium that does not require a decontamination step. Using NTM Elite agar, we were able to detect non-tuberculous mycobacteria in 27.7% (30/108) of water samples analyzed. The average time to NTM detection was 18 days, but some strains required longer to grow, perhaps due to the stressful environmental conditions (periodical disinfection of devices). NTM Elite agar’s effectiveness in inhibiting background flora was proven by the isolation of NTM from samples with and without background flora, showing no statistically significant differences in detection rates for different total viable counts of background flora (p = 0.4989). In conclusion, our findings indicate that effective NTM recovery from HCU- and ECMO-derived water samples can be achieved via filtration and direct culture of the filters on NTM Elite agar. This simple procedure can speed up laboratory work and provide an improved method, successfully resulting in low contamination and high detection rate, in addition to being less time-consuming. Its sensitivity and lack of a decontamination step make this protocol particularly useful for monitoring the effectiveness of device disinfection in hospital settings, even in the presence of low NTM loads. Reading timeframes should probably be extended to 7 weeks (i.e., well beyond the standard 4 weeks advised by the manufacturer), in order to isolate even the slow-growing mycobacteria. However, an extended incubation period is not necessary for exclusion of M. chimaera contamination of the devices, as M. chimaera isolation times do not generally exceed 3 weeks.
format Online
Article
Text
id pubmed-9518321
institution National Center for Biotechnology Information
language English
publishDate 2022
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-95183212022-09-29 A New Culture Method for the Detection of Non-Tuberculous Mycobacteria in Water Samples from Heater–Cooler Units and Extracorporeal Membrane Oxygenation Machines Ditommaso, Savina Giacomuzzi, Monica Memoli, Gabriele Garlasco, Jacopo Curtoni, Antonio Iannaccone, Marco Zotti, Carla M. Int J Environ Res Public Health Article The isolation of non-tuberculous mycobacteria (NTM) from cultures is particularly laborious due to the potential overgrowth of coexisting non-acid fast bacilli. To reduce the overgrowth of these non-mycobacterial organisms, a decontamination step with NaOH or cetylpyridinium chloride is highly recommended before plating the samples on the culture medium. However, due to their toxicity, decontamination solutions tend to decrease NTM recovery from clinical and environmental samples. Here, we tested an alternative method for NTM recovery based on the use of NTM Elite agar, a selective medium that does not require a decontamination step. Using NTM Elite agar, we were able to detect non-tuberculous mycobacteria in 27.7% (30/108) of water samples analyzed. The average time to NTM detection was 18 days, but some strains required longer to grow, perhaps due to the stressful environmental conditions (periodical disinfection of devices). NTM Elite agar’s effectiveness in inhibiting background flora was proven by the isolation of NTM from samples with and without background flora, showing no statistically significant differences in detection rates for different total viable counts of background flora (p = 0.4989). In conclusion, our findings indicate that effective NTM recovery from HCU- and ECMO-derived water samples can be achieved via filtration and direct culture of the filters on NTM Elite agar. This simple procedure can speed up laboratory work and provide an improved method, successfully resulting in low contamination and high detection rate, in addition to being less time-consuming. Its sensitivity and lack of a decontamination step make this protocol particularly useful for monitoring the effectiveness of device disinfection in hospital settings, even in the presence of low NTM loads. Reading timeframes should probably be extended to 7 weeks (i.e., well beyond the standard 4 weeks advised by the manufacturer), in order to isolate even the slow-growing mycobacteria. However, an extended incubation period is not necessary for exclusion of M. chimaera contamination of the devices, as M. chimaera isolation times do not generally exceed 3 weeks. MDPI 2022-08-26 /pmc/articles/PMC9518321/ /pubmed/36078363 http://dx.doi.org/10.3390/ijerph191710645 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Ditommaso, Savina
Giacomuzzi, Monica
Memoli, Gabriele
Garlasco, Jacopo
Curtoni, Antonio
Iannaccone, Marco
Zotti, Carla M.
A New Culture Method for the Detection of Non-Tuberculous Mycobacteria in Water Samples from Heater–Cooler Units and Extracorporeal Membrane Oxygenation Machines
title A New Culture Method for the Detection of Non-Tuberculous Mycobacteria in Water Samples from Heater–Cooler Units and Extracorporeal Membrane Oxygenation Machines
title_full A New Culture Method for the Detection of Non-Tuberculous Mycobacteria in Water Samples from Heater–Cooler Units and Extracorporeal Membrane Oxygenation Machines
title_fullStr A New Culture Method for the Detection of Non-Tuberculous Mycobacteria in Water Samples from Heater–Cooler Units and Extracorporeal Membrane Oxygenation Machines
title_full_unstemmed A New Culture Method for the Detection of Non-Tuberculous Mycobacteria in Water Samples from Heater–Cooler Units and Extracorporeal Membrane Oxygenation Machines
title_short A New Culture Method for the Detection of Non-Tuberculous Mycobacteria in Water Samples from Heater–Cooler Units and Extracorporeal Membrane Oxygenation Machines
title_sort new culture method for the detection of non-tuberculous mycobacteria in water samples from heater–cooler units and extracorporeal membrane oxygenation machines
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9518321/
https://www.ncbi.nlm.nih.gov/pubmed/36078363
http://dx.doi.org/10.3390/ijerph191710645
work_keys_str_mv AT ditommasosavina anewculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT giacomuzzimonica anewculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT memoligabriele anewculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT garlascojacopo anewculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT curtoniantonio anewculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT iannacconemarco anewculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT zotticarlam anewculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT ditommasosavina newculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT giacomuzzimonica newculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT memoligabriele newculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT garlascojacopo newculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT curtoniantonio newculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT iannacconemarco newculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines
AT zotticarlam newculturemethodforthedetectionofnontuberculousmycobacteriainwatersamplesfromheatercoolerunitsandextracorporealmembraneoxygenationmachines