Detection of viable but non-culturable legionella in hospital water network following monochloramine disinfection

Casini, Beatrice; Baggiani, Angelo; Totaro, Michele; Mansi, Antonella; Costa, Anna Laura; Aquino, Francesco; Miccoli, Mario; Valentini, Paola; Bruschi, Fabrizio; Lopalco, Pietro Luigi; Privitera, Gaetano Pierpaolo

doi:10.1016/j.jhin.2017.09.006

Cited by 45 publications

(39 citation statements)

References 29 publications

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“…First of all, the observed decrease in WDS contamination cannot be attributed only to MC but rather to the sum of actions that were taken to eradicate the contamination (chlorine hyper-dosage, hyper-dosage of MC, flushing). Thus, the effectiveness of the disinfectant needs to be carefully evaluated in the long run, mainly because it has been recently reported the emergence of viable but non-culturable (VNBC) Legionella during a long period of continuous MC treatment of a hospital water network [46]. Secondly, estimated energy savings in the present study was of 2219.00 € per year.…”

Section: Discussionmentioning

confidence: 89%

Preventing Healthcare-Associated Legionellosis: Results after 3 Years of Continuous Disinfection of Hot Water with Monochloramine and an Effective Water Safety Plan

Coniglio

Ferrante

Yassin

2018

IJERPH

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The purpose of this study is to report the experience of the implementation and application of a 3-year Water Safety Plan (WSP) together with the secondary disinfection of water by monochloramine to control and prevent healthcare-associated legionellosis in an Italian hospital strongly colonized by Legionella. Risk assessment was carried out by the WSP team. The main critical control points focused on in developing the WSP for the control of Legionella was the water distribution system. A sampling plan for the detection of Legionella was implemented. A widespread contamination of the hot water distribution system by L. pneumophila sg5 was found. Results after 3 years of the continuous disinfection of hot water with monochloramine indicate the eradication of Legionella. The implementation and application of a WSP in a hospital, together with the disinfection of the water distribution system with monochloramine, can be effective in controlling the growth of Legionella and in preventing nosocomial legionellosis.

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Section: Discussionmentioning

confidence: 89%

Preventing Healthcare-Associated Legionellosis: Results after 3 Years of Continuous Disinfection of Hot Water with Monochloramine and an Effective Water Safety Plan

Coniglio

Ferrante

Yassin

2018

IJERPH

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“…Strain Philadelphia is a clinical isolate that is historically responsible for the very first outbreak. It possesses gene traits that allow for multiplication in a number of hosts such as peripheral blood mononuclear cells, peritoneal macrophages, and A. castellanii, A. polyphaga, or A. lenticulate [26][27][28][29]. The Philadelphia strain is, according to the EN 13623 European standard, the only strain for which testing is required to validate a disinfectant against Legionella in Europe.…”

Section: Discussionmentioning

confidence: 99%

Intracellular Behaviour of Three Legionella pneumophila Strains within Three Amoeba Strains, Including Willaertia magna C2c Maky

Hasni

Jarry²,

Quélard³

et al. 2020

Pathogens

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Legionella pneumophila is a facultative intracellular pathogen found in aquatic environments as planktonic cells within biofilms and as intracellular parasites of free-living amoebae such as Acanthamoeba castellanii. This pathogen bypasses the elimination mechanism to replicate within amoebae; however, not all amoeba species support the growth of L. pneumophila. Willaertia magna C2c Maky, a non-pathogenic amoeba, was previously demonstrated to possess the ability to eliminate the L. pneumophila strain Paris. Here, we study the intracellular behaviour of three L. pneumophila strains (Paris, Philadelphia, and Lens) within W. magna C2c Maky and compare this strain to A. castellanii and W. magna Z503, which are used as controls. We observe the intracellular growth of strain Lens within W. magna Z503 and A. castellanii at 22 °C and 37 °C. Strain Paris grows within A. castellanii at any temperature, while it only grows at 22 °C within W. magna Z503. Strain Philadelphia proliferates only within A. castellanii at 37 °C. Within W. magna C2c Maky, none of the three legionella strains exhibit intracellular growth. Additionally, the ability of W. magna C2c Maky to decrease the number of internalized L. pneumophila is confirmed. These results support the idea that W. magna C2c Maky possesses unique behaviour in regard to L. pneumophila strains.

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“…The discrepancy found between qPCR and culture has been discussed in literature at great length and is mostly due to the detection of dead cells or VBNC cells via qPCR which then lead to an overestimation of the bacterial burden of the sample. qPCR detects cells that entered the VBNC state after the use of disinfectants or Legionella living in protozoa, which would not be detected using the culture method [8]. The culture method has several limitations, too; Legionella might get inhibited or overgrown by competing microbiota and the method is also biased towards the isolation of L. pneumophila sg1 [2,16].…”

Section: Discussionmentioning

confidence: 99%

“…These features make constant monitoring of possible contaminations in risk sources and epidemiological investigations following outbreaks in a timely manner a necessity for the public safety and health [2]. Recently, studies have shown success in eradication of Legionella from hospital water networks by using new methods: Totaro et al propose the installation of time-flow taps in proximity to dead-legs in the pipe system for efficient flushing of the system, whereas others propose the use of monochloramine instead of the widely used chlorine dioxide or the use of hydrogen peroxide as a biocide against Legionella colonization in hospital water networks [8][9][10]. In Austria drinking water is not chlorinated, but often treated with UV according to ÖNORM M 5873.…”

Section: Introductionmentioning

confidence: 99%

Legionella Detection in Environmental Samples as an Example for Successful Implementation of qPCR

Toplitsch¹,

Platzer²,

Pfeifer³

et al. 2018

Water

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Waterborne diseases are a serious threat because of their ability to infect a high number of individuals in a short time span, such as during outbreaks of Legionellosis. This significantly highlights the need for the rapid detection and quantification of bacteria in environmental water samples. The aim of this study was to investigate the feasibility of quantitative Polymerase Chain Reaction (qPCR) for the detection of Legionellapneumophila (L. pneumophila) in environmental water samples and comparison of standard culture methods for Legionella detection with qPCR. Our study reached a negative predictive value (NPV) for L. pneumophila of 80.7% and for L. pneumophila serogroup 1 (sg1) the calculated NPV was 87.0%. The positive predictive value (PPV) for L. pneumophila was 53.9% and for L. pneumophila sg1 PPV was 21.4%. Results showed a correlation between qPCR and culture with an R2 value of 0.8973 for L. pneumophila, whereas no correlation was observed for the detection of L. pneumophila sg1. In our study, qPCR proved useful for the identification of L. pneumophila negative samples. However, despite the obvious benefits (sample handling, rapid generation of results), qPCR needs to be improved regarding the PPV before it can replace culture in water quality assessment.

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Detection of viable but non-culturable legionella in hospital water network following monochloramine disinfection

Cited by 45 publications

References 29 publications

Preventing Healthcare-Associated Legionellosis: Results after 3 Years of Continuous Disinfection of Hot Water with Monochloramine and an Effective Water Safety Plan

Preventing Healthcare-Associated Legionellosis: Results after 3 Years of Continuous Disinfection of Hot Water with Monochloramine and an Effective Water Safety Plan

Intracellular Behaviour of Three Legionella pneumophila Strains within Three Amoeba Strains, Including Willaertia magna C2c Maky

Legionella Detection in Environmental Samples as an Example for Successful Implementation of qPCR

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