scholarly journals Comparison of two culture methods for the enumeration of Legionella pneumophila from potable water samples

2021 ◽  
Author(s):  
Laura A. Boczek ◽  
Min Tang ◽  
Casey Formal ◽  
Darren Lytle ◽  
Hodon Ryu
Keyword(s):  
Legionella Pneumophila ◽  
Water Samples ◽  
Potable Water ◽  
High Sensitivity ◽  
High Specificity ◽  
The United States ◽  
Contaminated Water ◽  
Plumbing System ◽  
Culture Methods ◽  
False Negatives

Abstract Legionella infections have steadily increased in the United States over the last 20 years, and most of these infections have been attributed to contaminated water. The gold standard for confirmation of Legionella presence in water is culturing with Buffered Charcoal Yeast Extract (BCYE) agar. Following many modifications, this method is still time-consuming, expensive, and can take longer than 10 days for full confirmation. The Legiolert is a newer and simpler culture product that is claimed to be able to quantify Legionella pneumophila in 7 days with high sensitivity and specificity and does not need further confirmation for the presence of L. pneumophila. This study compared the culturability of L. pneumophila occurring in a simulated home plumbing system using both Legiolert and BCYE agar methods. Out of 185 water samples, Legiolert and BCYE method detected L. pneumophila in 83 and 85% of the samples, respectively. The two methods were determined to be statistically equivalent for culturability of L. pneumophila, though the detected levels by Legiolert were slightly higher than the BCYE method. The molecular confirmation of positive (n = 254) and negative wells (n = 82) with Legiolert also showed a high specificity of 96.5% (i.e., 3.5% false positives (9/254) and 0% false negatives (0/82)).

scholarly journals Evaluation of a most probable number method for the enumeration of Legionella pneumophila from North American potable and nonpotable water samples

2017 ◽  
Vol 16 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Ray Petrisek ◽  
Jonathon Hall
Keyword(s):  
Legionella Pneumophila ◽  
Water Samples ◽  
Potable Water ◽  
High Specificity ◽  
Most Probable Number ◽  
Water Type ◽  
Probable Number ◽  
Standard Methods ◽  
Water And Wastewater ◽  
Higher Sensitivity

Abstract This study compares the performance of a novel most probable number (MPN) method (Legiolert™/Quanti-Tray®) with Standard Methods for the Examination of Water and Wastewater 9260 J for the enumeration of Legionella pneumophila from potable and nonpotable waters. Data from the study showed that Legiolert exhibited higher sensitivity for the detection of L. pneumophila for potable water and equivalent sensitivity for nonpotable water. The Legiolert medium had a high specificity with no false positive signals reported for either water type. The new method represents a significant improvement in usability and accuracy in the enumeration of L. pneumophila.

scholarly journals Impact of Chlorine and Chloramine on the Detection and Quantification of Legionella pneumophila and Mycobacterium Species

2019 ◽  
Vol 85 (24) ◽  
Author(s):  
Maura J. Donohue ◽  
Steve Vesper ◽  
Jatin Mistry ◽  
Joyce M. Donohue
Keyword(s):  
United States ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
Potable Water ◽  
Tap Water ◽  
The United States ◽  
Water Disinfection ◽  
Nontuberculous Mycobacterium ◽  
Content Type ◽  
Chlorine Residual

ABSTRACT Potable water can be a source of transmission for legionellosis and nontuberculous mycobacterium (NTM) infections and diseases. Legionellosis is caused largely by Legionella pneumophila, specifically serogroup 1 (Sg1). Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium abscessus are three leading species associated with pulmonary NTM disease. The estimated rates of these diseases are increasing in the United States, and the cost of treatment is high. Therefore, a national assessment of water disinfection efficacy for these pathogens was needed. The disinfectant type and total chlorine residual (TClR) were investigated to understand their influence on the detection and concentrations of the five pathogens in potable water. Samples (n = 358) were collected from point-of-use taps (cold or hot) from locations across the United States served by public water utilities that disinfected with chlorine or chloramine. The bacteria were detected and quantified using specific primer and probe quantitative-PCR (qPCR) methods. The total chlorine residual was measured spectrophotometrically. Chlorine was the more potent disinfectant for controlling the three mycobacterial species. Chloramine was effective at controlling L. pneumophila and Sg1. Plotting the TClR associated with positive microbial detection showed that an upward TClR adjustment could reduce the bacterial count in chlorinated water but was not as effective for chloramine. Each species of bacteria responded differently to the disinfection type, concentration, and temperature. There was no unifying condition among the water characteristics studied that achieved microbial control for all. This information will help guide disinfectant decisions aimed at reducing occurrences of these pathogens at consumer taps and as related to the disinfectant type and TClR. IMPORTANCE The primary purpose of tap water disinfection is to control the presence of microbes. This study evaluated the role of disinfectant choice on the presence at the tap of L. pneumophila, its Sg1 serogroup, and three species of mycobacteria in tap water samples collected at points of human exposure at locations across the United States. The study demonstrates that microbial survival varies based on the microbial species, disinfectant, and TClR.

scholarly journals Performance of Legiolert Test vs. ISO 11731 to Confirm Legionella pneumophila Contamination in Potable Water Samples

Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 690 ◽  
Author(s):  
Maria Scaturro ◽  
Matteo Buffoni ◽  
Antonietta Girolamo ◽  
Sandra Cristino ◽  
Luna Girolamini ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
Gold Standard ◽  
Liquid Culture ◽  
Potable Water ◽  
Culture Method ◽  
Alternative Methods ◽  
Significant Difference

Detection and enumeration of Legionella in water samples is of great importance for risk assessment analysis. The plate culture method is the gold standard, but has received several well-known criticisms, which have induced researchers to develop alternative methods. The purpose of this study was to compare Legionella counts obtained by the analysis of potable water samples through the plate culture method and through the IDEXX liquid culture Legiolert method. Legionella plate culture, according to ISO 11731:1998, was performed using 1 L of water. Legiolert was performed using both the 10 mL and 100 mL Legiolert protocols. Overall, 123 potable water samples were analyzed. Thirty-seven (30%) of them, positive for L. pneumophila, serogroups 1 or 2–14 by plate culture, were used for comparison with the Legiolert results. The Legiolert 10 mL test detected 34 positive samples (27.6%) and the Legiolert 100 mL test detected 37 positive samples, 27.6% and 30% respectively, out of the total samples analyzed. No significant difference was found between either the Legiolert 10 mL and Legiolert 100 mL vs. the plate culture (p = 0.9 and p = 0.3, respectively) or between the Legiolert 10 mL and Legiolert 100 mL tests (p = 0.83). This study confirms the reliability of the IDEXX Legiolert test for Legionella pneumophila detection and enumeration, as already shown in similar studies. Like the plate culture method, the Legiolert assay is also suitable for obtaining isolates for typing purposes, relevant for epidemiological investigations.

Fatal NosocomialLegionella pneumophilaInfection Due to Exposure to Contaminated Water From a Washbasin in a Hematology Unit

2008 ◽  
Vol 29 (11) ◽  
pp. 1091-1093 ◽  
Author(s):  
Alexandre Brûlet ◽  
Marie-Christine Nicolle ◽  
Marine Giard ◽  
Franck-Emmanuel Nicolini ◽  
Mauricette Michallet ◽  
...  
Keyword(s):  
Nosocomial Infection ◽  
Water Supply ◽  
Legionella Pneumophila ◽  
Potable Water ◽  
Contaminated Water ◽  
Genomic Profile ◽  
Source Of Infection ◽  
Potable Water Supply

A fatal nosocomial infection withLegionella pneumophilaserogroup 5 occurred in a patient with leukemia. Isolates recovered from both the potable water supply and the patient showed an identical genomic profile. With no other exposure identified, the water from the washbasin was evidently the source of infection.

scholarly journals Nosocomial legionella pneumonia: demonstration of potable water as the source of infection

1988 ◽  
Vol 101 (3) ◽  
pp. 647-654 ◽  
Author(s):  
B. Ruf ◽  
D. Schürmann ◽  
I. Horbrach ◽  
K. Seodel ◽  
H. D. Pohle
Keyword(s):  
Monoclonal Antibodies ◽  
Water Supply ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
Potable Water ◽  
Supply System ◽  
University Hospital ◽  
Environmental Isolates ◽  
Legionella Pneumonia ◽  
Source Of Infection

SUMMARYFrom January 1983 until December 1985, 35 cases of sporadic nosocomial legionella pneumonia, all caused byLegionella pneumophila, were diagnosed in a university hospital.L. pneumophilaserogroup (SG) 1 was cultured from 12 of the 35 cases and compared to correspondingL. pneumophilaSG 1 isolates from water outlets in the patients' immediate environment by subtyping with monoclonal antibodies. The corresponding environmental isolates were identical to 9 out of 12 (75%) of those from the cases. However, even in the remaining three cases identical subtypes were found distributed throughout the hospital water supply. From the hospital water supply four different subtypes ofL. pneumophilaSG 1 were isolated, three of which were implicated in legionella pneumonia. Of 453 water samples taken during the study 298 (65.8%) were positive for legionellae. Species ofLegionellaother thanL. pneumophilahave not been isolated. This may explain the exclusiveness ofL.pneumophilaas the legionella pneumonia-causing agent. Our results suggest that the water supply system was the source of infection.

scholarly journals Comparison of Updated Methods for Legionella Detection in Environmental Water Samples

2021 ◽  
Vol 18 (10) ◽  
pp. 5436
Author(s):  
Daniela Toplitsch ◽  
Sabine Platzer ◽  
Romana Zehner ◽  
Stephanie Maitz ◽  
Franz Mascher ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Water Samples ◽  
Limit Of Detection ◽  
Culture Method ◽  
Environmental Water ◽  
Microbial Flora ◽  
Culture Methods ◽  
Outbreak Investigations ◽  
Standard Culture ◽  
Selection Of

The difficulty of cultivation of Legionella spp. from water samples remains a strenuous task even for experienced laboratories. The long incubation periods for Legionellae make isolation difficult. In addition, the water samples themselves are often contaminated with accompanying microbial flora, and therefore require complex cultivation methods from diagnostic laboratories. In addition to the recent update of the standard culture method ISO 11731:2017, new strategies such as quantitative PCR (qPCR) are often discussed as alternatives or additions to conventional Legionella culture approaches. In this study, we compared ISO 11731:2017 with qPCR assays targeting Legionella spp., Legionella pneumophila, and Legionella pneumophila serogroup 1. In samples with a high burden of accompanying microbial flora, qPCR shows an excellent negative predictive value for Legionella pneumophila, thus making qPCR an excellent tool for pre-selection of negative samples prior to work-intensive culture methods. This and its low limit of detection make qPCR a diagnostic asset in Legionellosis outbreak investigations, where quick-risk assessments are essential, and are a useful method for monitoring risk sites.

scholarly journals Reliability of Cobas Amplicor PCR test in detection of Mycobacterium tuberculosis in respiratory and nonorespiratory specimens

2009 ◽  
Vol 66 (12) ◽  
pp. 992-997
Author(s):  
Zorica Lepsanovic ◽  
Dejana Savic ◽  
Branka Tomanovic
Keyword(s):  
Mycobacterium Tuberculosis ◽  
High Sensitivity ◽  
High Specificity ◽  
Diagnostic Methods ◽  
Nucleic Acid Amplification ◽  
Culture Methods ◽  
Predictive Values ◽  
Polymerase Chain ◽  
Low Sensitivity ◽  
Sensitivity Specificity

Background/Aim. Traditional methods for detection of mycobacteria, such as microscopic examination for the presence of acid-fast bacilli and isolation of the organism by culture, have either a low sensitivity and/or specificity, or take weeks before a definite result is available. Molecular methods, especially those based on nucleic acid amplification, are rapid diagnostic methods which combine high sensitivity and high specificity. The aim of this study was to determine the usefulness of the Cobas Amplicor Mycobacterium tuberculosis polymerase chain reaction (CAPCR) assay in detecting the tuberculosis cause in respiratory and nonrespiratory specimens (compared to culture). Methods. Specimens were decontaminated by the N-acetyl-L-cystein- NaOH method. A 500 ?L aliquot of the processed specimen were used for inoculation of L?wenstein-Jensen (L-J) slants, a drop for acid-fast staining, and 100 ?L for PCR. The Cobas Amplicor PCR was performed according to the manufacturer's instructions. Results. A total of 110 respiratory and 355 nonrespiratory specimens were investigated. After resolving discrepancies by reviewing medical history, overall sensitivity, specificity, and positive and negative predictive values for CA-PCR assay compared to culture, were 83%, 100%, 100%, and 96.8%, respectively. In comparison, they were 50%, 99.7%, 87.5%, and 98%, respectively, for the nonrespiratory specimens. The inhibition rate was 2.8% for respiratory, and 7.6% for nonrespiratory specimens. Conclusion. CA-PCR is a reliable assay that enables specialists to start treatment promptly on a positive test result. Lower value for specificity in a group of nonrespiratory specimens is a consequence of an extremely small number of mycobacteria in some of them.

scholarly journals Contamination of Water Sources of Karaj Hospitals with Legionella pneumophila and Campylobacter jejuni

2020 ◽  
Vol 8 (4) ◽  
pp. 142-146
Author(s):  
Niloofar Ghomimaghsad ◽  
Somayeh Yaslianifard ◽  
Mohammad Mohammadzadeh ◽  
Masoud Dadashi ◽  
Mohammad Noorisepehr
Keyword(s):  
Campylobacter Jejuni ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
High Efficiency ◽  
Cold Water ◽  
Bacterial Species ◽  
Water Sources ◽  
Hot Water ◽  
Water Supply Systems ◽  
Contaminated Water

Background: One of the most common routes of infection development in humans is contaminated water. Legionella pneumophila and Campylobacter jejuni are the important causes of community- and hospital-acquired pneumonia and gastroenteritis that are transmitted to humans via the inhalation of contaminated water droplets and consumption of contaminated water, respectively. Thus, continuous monitoring of the water supply systems for these pathogens has great importance in public health. Objective: This study aimed to evaluate the water contamination of Karaj hospitals with these two bacterial species. Materials and Methods: In this study, 62 water samples were obtained from different parts of the hospitals of Karaj from April to September 2019, including air conditioning systems, dialysis equipment, ventilation tanks, and different wards of a hospital such as infectious diseases, pediatrics, gastroenterology, dialysis, and intensive and neonatal intensive care units. The samples were collected in sterile containers and immediately transferred to the laboratory for further analysis. The culture on specific media, staining, and biochemical tests were performed to identify the L. pneumophila and C. jejuni. Results: Out of 62 water samples, 25.8% (16 samples) were positive for L. pneumophila; 68.75% were observed in hot water samples, and 31.25% were attributed to cold water samples. Among 62 samples, 4.84% (3 samples) were positive for C. jejuni, which were all detected in hot water samples. Conclusion: Considering that the methods of water refinery of municipal water have no high efficiency, the quality improvement of the water sources of hospitals seems to be necessary.

scholarly journals Legionellaceae in the potable water of Nova Scotia hospitals and Halifax residences

1994 ◽  
Vol 112 (1) ◽  
pp. 143-150 ◽  
Author(s):  
T. Marrie ◽  
P. Green ◽  
S. Burbridge ◽  
G. Bezanson ◽  
S. Neale ◽  
...  
Keyword(s):  
Nova Scotia ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
Potable Water ◽  
Calcium Content ◽  
Potassium Nitrate ◽  
Hot Water ◽  
Total System ◽  
Single Family ◽  
Water Heaters

SummaryWater was cultured from 39 of 48 hospitals (7 Halifax hospitals and 32 non-Halifax hospitals) in the province of Nova Scotia and from 90 residences (74 private dwellings, 16 apartments) in Halifax to determine the frequency of legionella contamination. Six of seven Halifax hospitals had Legionellaceae isolated from their potable water compared with 3 of 32 non-Halifax hospitals (P < 0.0001). Overall. 19 of 59 (32%) of the water samples from Halifax hospitals were positive for legionellae compared with 5 of 480 (1%) samples from non-Halifax hospitals (P < 0.0000). Five of the six positive Halifax hospitals hadLegionella pneumophilaserogroup 1 and 1 hadL. longbeachaeserogroup 2 recovered from their potable water. Legionella contamination was associated with older, larger (> 50 beds) hospitals with total system recirculation. These hospitals also had water with a higher pH and calcium content but lower sodium, potassium, nitrate, iron and copper content.Fourteen of the 225 (6.2%) water samples from Halifax residences were positive for legionellae – 8% (6/74) of the single family dwellings were positive, compared with 25% (4/16) apartments. The positivity rate of 15.7% for the 19 electric hot-water heaters in Halifax homes was not significantly different from the 32% positivity for Halifax hospitals.L. longbeachaeaccounted for 2 of the 14 isolates of legionellae from Halifax homes.

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