Isolation of <i>Legionella</i> from water samples using various culture methods

Kusnetsov, Jaana; Jousimies‐Somer, Hannele; Nevalainen, Aino; Martikainen, Pertti J.

doi:10.1111/j.1365-2672.1994.tb01611.x

Cited by 17 publications

(11 citation statements)

References 17 publications

(27 reference statements)

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“…1986; Stout et al . 1992; Kusnetsov et al . 1994), direct inoculum detected significantly higher concentrations compared with the techniques involving decontamination, which brought about an average reduction of 67–68% in detectable Legionellae.…”

Section: Discussionmentioning

confidence: 99%

Comparison of selective procedures for isolation and enumeration ofLegionellaspecies from hot water systems

Leoni

Legnani

2001

Journal of Applied Microbiology

112

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E. LEONI AND P.P. LEGNANI. 2001. Various sample pre‐treatment techniques and different growth media for the isolation of Legionellae from hot water supplies in public buildings were compared. A total of 102 hot water samples from taps and showers was examined. The highest recovery frequency was obtained with the heat pre‐treatment method and using the selective medium GVPC. However, the results differed according to the concentration of legionellas. In the case of low plate counts (≤5000 cfu l−1), the heat pre‐treatment technique gave a significantly higher percentage of positive samples compared with other techniques (P < 0·05). With increasing concentration, the differences between the procedures decreased until they became statistically not significant for concentrations above 50 000 cfu l−1. The direct inoculum method allowed a significantly higher detection of concentrations (P < 0·001) compared with heat and acid decontamination methods, which brought about a 67–68% reduction in detectable Legionellae. Heat decontamination techniques show greater sensitivity and specificity. However, they underestimate the number of legionellas. In environmental surveillance programmes, this underestimate must be taken into consideration when assessing the health risk.

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Section: Discussionmentioning

confidence: 99%

Comparison of selective procedures for isolation and enumeration ofLegionellaspecies from hot water systems

Leoni

Legnani

2001

Journal of Applied Microbiology

112

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“…Various media, generally containing amino acid supplements and antimicrobial Q 1999 Blackwell Science Ltd, Environmental Microbiology, 1, 283±293 inhibitors, can be used to cultivate Legionella species (Atlas, 1995). Often, pre-enrichment with various inhibitors is needed to eliminate populations of other bacteria (Roberts et al, 1987;Kusnetsov et al, 1994a). Kasuga et al (1999), for example, recently reported that combined pretreatment with acid after heating and the addition of polymyxin B and oxytetracycline into the selective cultivation medium is a useful method for the detection of Legionella sp.…”

Section: Detection and Disinfectionmentioning

confidence: 99%

Legionella: from environmental habitats to disease pathology, detection and control

Atlas

1999

Environmental Microbiology

210

148

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Studies on Legionella show a continuum from environment to human disease. Legionellosis is caused by Legionella species acquired from environmental sources, principally water sources such as cooling towers, where Legionella grows intracellularly in protozoa within biofilms. Aquatic biofilms, which are widespread not only in nature, but also in medical and dental devices, are ecological niches in which Legionella survives and proliferates and the ultimate sources to which outbreaks of legionellosis can be traced. Invasion and intracellular replication of L. pneumophila within protozoa in the environment play a major role in the transmission of Legionnaires' disease. Protozoa provide the habitats for the environmental survival and reproduction of Legionella species. L. pneumophila proliferates intracellularly in various species of protozoa within vacuoles studded with ribosomes, as it also does within macrophages. Growth within protozoa enhances the environmental survival capability and the pathogenicity (virulence) of Legionella. The growth requirements of Legionella, the ability of Legionella to enter a viable non‐culturable state, the association of Legionella with protozoa and the occurrence of Legionella within biofilms complicates the detection of Legionella and epidemiological investigations of legionellosis. Polymerase chain reaction (PCR) methods have been developed for the molecular detection of Legionella and used in environmental and epidemiological studies. Various physical and chemical disinfection methods have been developed to eliminate Legionella from environmental sources, but gaining control of Legionella in environmental waters, where they are protected from disinfection by growing within protozoa and biofilms, remains a challenge, and one that must be overcome in order to eliminate sporadic outbreaks of legionellosis.

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“…Epidemiological study demonstrates that legionnaire's disease is associated with environmental water system especially with the cooling tower system (Kusnetsov et al, 1994;Craun et al, 2010). Gold standard method for detection of Legionella species is based on cultivation (Den et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Comparative study on sampling methods for monitoring Legionella species in environmental water

Zhan¹,

Hu²,

Zhu³

2014

Afr. J. Microbiol. Res.

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Infections caused by Legionella spp. are considered an emerging public health problem and are linked to high rates of mortality and morbidity, if not properly treated. This study analyzes 76 samples of water in Guangzhou with the aim of obtaining a more efficient means based on culture to isolate the genus Legionella. A comparative assessment of techniques recommended was performed on monitoring Legionella spp. in environmental water samples. Fourteen (14) sampling methods included in four categories based on concentration (filtration or centrifugation), acid buffer treatment (no acid treatment, treatment for 10 min), thermal treatment (no thermal treatment or treated for 30 min in 50°C) and heat enrich the samples in 37°C for 72 h were tested to identify their sensitivity. The four categories methodologies were assembled by different procedures and 14 methods were obtained to compare the efficiency for isolating Legionella in 76 water samples and in which Legionella were isolated from 42 water samples through these 14 methods. Merit and demerit of each single method was evaluated. Results suggest that a single category methodology for water sampling was insufficient to isolate Legionella spp. from water samples. Some Legionella positive water samples were missed through a single category methodology which made the results mistranslation. PSF category methods in this study were recommended methods and they could isolate Legionella species from 78.6% Legionella positive water samples; and if time was enough, PSF category methods combined with ERCT category methods to isolate Legionella from water samples are strongly recommended. Legionella were isolated from 41 water samples through these two category methods, it only missed 2.4% positive water sample. The results obtained, highlighted the importance of improving culture method for the identification of Legionella in water samples.

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Isolation of Legionella from water samples using various culture methods

Cited by 17 publications

References 17 publications

Comparison of selective procedures for isolation and enumeration ofLegionellaspecies from hot water systems

Comparison of selective procedures for isolation and enumeration ofLegionellaspecies from hot water systems

Legionella: from environmental habitats to disease pathology, detection and control

Comparative study on sampling methods for monitoring Legionella species in environmental water

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