Evaluation of Recommended Water Sample Collection Methods and the Impact of Holding Time on <i>Legionella</i> Recovery and Variability from Healthcare Building Water Systems
Water safety and management programs (WSMP) utilize field measurements to evaluate control limits and monitor water quality parameters including <i>Legionella</i> presence. This monitoring is important to verify that the plan is being implemented properly. However, once it has been deter...
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doaj-dcd30913b008445887e20bca84575fe42020-11-25T04:06:14ZengMDPI AGMicroorganisms2076-26072020-11-0181770177010.3390/microorganisms8111770Evaluation of Recommended Water Sample Collection Methods and the Impact of Holding Time on <i>Legionella</i> Recovery and Variability from Healthcare Building Water SystemsMarisa B. Hirsh0Julianne L. Baron1Sue M. Mietzner2John D. Rihs3Mohamed H. Yassin4Janet E. Stout5Special Pathogens Laboratory, Pittsburgh, PA 15219, USASpecial Pathogens Laboratory, Pittsburgh, PA 15219, USASpecial Pathogens Laboratory, Pittsburgh, PA 15219, USASpecial Pathogens Laboratory, Pittsburgh, PA 15219, USADepartment of Infection Control, UPMC Mercy Hospital, Pittsburgh, PA 15219, USASpecial Pathogens Laboratory, Pittsburgh, PA 15219, USAWater safety and management programs (WSMP) utilize field measurements to evaluate control limits and monitor water quality parameters including <i>Legionella</i> presence. This monitoring is important to verify that the plan is being implemented properly. However, once it has been determined when and how to sample for <i>Legionella</i>, it is important to choose appropriate collection and processing methods. We sought to compare processing immediate and flushed samples, filtration of different volumes collected, and sample hold times. Hot water samples were collected immediately and after a 2-min flush. These samples were plated directly and after filtration of either 100 mL, 200 mL, or 1 L. Additionally, unflushed samples were collected and processed immediately and after 1, 24, and 48 h of hold time. We found that flushed samples had significant reductions in <i>Legionella</i> counts compared to immediate samples. Processing 100 mL of that immediate sample both directly and after filter concentration yielded the highest concentration and percent sample positivity, respectively. We also show that there was no difference in culture values from time 0 compared to hold times of 1 h and 24 h. At 48 h, there were slightly fewer <i>Legionella</i> recovered than at time 0. However, <i>Legionella</i> counts were so variable based on sampling location and date that this hold time effect was minimal. The interpretation of <i>Legionella</i> culture results depends on the sample collection and processing methods used, as these can have a huge impact on the success of sampling and the validation of control measures.https://www.mdpi.com/2076-2607/8/11/1770<i>Legionella</i>sample collectionsample processingenvironmental water samplesculturehold time |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Marisa B. Hirsh Julianne L. Baron Sue M. Mietzner John D. Rihs Mohamed H. Yassin Janet E. Stout |
spellingShingle |
Marisa B. Hirsh Julianne L. Baron Sue M. Mietzner John D. Rihs Mohamed H. Yassin Janet E. Stout Evaluation of Recommended Water Sample Collection Methods and the Impact of Holding Time on <i>Legionella</i> Recovery and Variability from Healthcare Building Water Systems Microorganisms <i>Legionella</i> sample collection sample processing environmental water samples culture hold time |
author_facet |
Marisa B. Hirsh Julianne L. Baron Sue M. Mietzner John D. Rihs Mohamed H. Yassin Janet E. Stout |
author_sort |
Marisa B. Hirsh |
title |
Evaluation of Recommended Water Sample Collection Methods and the Impact of Holding Time on <i>Legionella</i> Recovery and Variability from Healthcare Building Water Systems |
title_short |
Evaluation of Recommended Water Sample Collection Methods and the Impact of Holding Time on <i>Legionella</i> Recovery and Variability from Healthcare Building Water Systems |
title_full |
Evaluation of Recommended Water Sample Collection Methods and the Impact of Holding Time on <i>Legionella</i> Recovery and Variability from Healthcare Building Water Systems |
title_fullStr |
Evaluation of Recommended Water Sample Collection Methods and the Impact of Holding Time on <i>Legionella</i> Recovery and Variability from Healthcare Building Water Systems |
title_full_unstemmed |
Evaluation of Recommended Water Sample Collection Methods and the Impact of Holding Time on <i>Legionella</i> Recovery and Variability from Healthcare Building Water Systems |
title_sort |
evaluation of recommended water sample collection methods and the impact of holding time on <i>legionella</i> recovery and variability from healthcare building water systems |
publisher |
MDPI AG |
series |
Microorganisms |
issn |
2076-2607 |
publishDate |
2020-11-01 |
description |
Water safety and management programs (WSMP) utilize field measurements to evaluate control limits and monitor water quality parameters including <i>Legionella</i> presence. This monitoring is important to verify that the plan is being implemented properly. However, once it has been determined when and how to sample for <i>Legionella</i>, it is important to choose appropriate collection and processing methods. We sought to compare processing immediate and flushed samples, filtration of different volumes collected, and sample hold times. Hot water samples were collected immediately and after a 2-min flush. These samples were plated directly and after filtration of either 100 mL, 200 mL, or 1 L. Additionally, unflushed samples were collected and processed immediately and after 1, 24, and 48 h of hold time. We found that flushed samples had significant reductions in <i>Legionella</i> counts compared to immediate samples. Processing 100 mL of that immediate sample both directly and after filter concentration yielded the highest concentration and percent sample positivity, respectively. We also show that there was no difference in culture values from time 0 compared to hold times of 1 h and 24 h. At 48 h, there were slightly fewer <i>Legionella</i> recovered than at time 0. However, <i>Legionella</i> counts were so variable based on sampling location and date that this hold time effect was minimal. The interpretation of <i>Legionella</i> culture results depends on the sample collection and processing methods used, as these can have a huge impact on the success of sampling and the validation of control measures. |
topic |
<i>Legionella</i> sample collection sample processing environmental water samples culture hold time |
url |
https://www.mdpi.com/2076-2607/8/11/1770 |
work_keys_str_mv |
AT marisabhirsh evaluationofrecommendedwatersamplecollectionmethodsandtheimpactofholdingtimeonilegionellairecoveryandvariabilityfromhealthcarebuildingwatersystems AT juliannelbaron evaluationofrecommendedwatersamplecollectionmethodsandtheimpactofholdingtimeonilegionellairecoveryandvariabilityfromhealthcarebuildingwatersystems AT suemmietzner evaluationofrecommendedwatersamplecollectionmethodsandtheimpactofholdingtimeonilegionellairecoveryandvariabilityfromhealthcarebuildingwatersystems AT johndrihs evaluationofrecommendedwatersamplecollectionmethodsandtheimpactofholdingtimeonilegionellairecoveryandvariabilityfromhealthcarebuildingwatersystems AT mohamedhyassin evaluationofrecommendedwatersamplecollectionmethodsandtheimpactofholdingtimeonilegionellairecoveryandvariabilityfromhealthcarebuildingwatersystems AT janetestout evaluationofrecommendedwatersamplecollectionmethodsandtheimpactofholdingtimeonilegionellairecoveryandvariabilityfromhealthcarebuildingwatersystems |
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