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Touge C, Nakatsu M, Sugimoto M, Takamura E, Sakamoto H. A Biochemical Corrosion Monitoring Sensor with a Silver/Carbon Comb Structure for the Detection of Living Escherichia coli. ACS OMEGA 2023; 8:43511-43520. [PMID: 38027348 PMCID: PMC10666268 DOI: 10.1021/acsomega.3c03632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 10/20/2023] [Accepted: 10/25/2023] [Indexed: 12/01/2023]
Abstract
For the detection and monitoring of live bacteria, we propose a biochemical corrosion monitoring (BCM) sensor that measures galvanic current by using a Ag/C sensor comprising silver and carbon comb electrodes. The deposition of an Escherichia coli suspension containing an LB liquid medium on the Ag/C sensor increased the galvanic current. The time required for the current to reach 20 nA is defined as T20. T20 tends to decrease as the initial number of E. coli in the E. coli solution increases. A linear relationship was obtained between the logarithm of the E. coli count and T20 in a bacterial count range of 1-108 cfu/mL under culture conditions in which the growth rate of the bacteria was constant. Hence, the number of live E. coli could be determined from T20. Ag2S precipitation was observed on the surface of the Ag electrode of the Ag/C sensor, where an increase in the current was observed. This generation of galvanic current was attributed to the reaction between a small amount of free H2S metabolized by E. coli in the bacterial solution during its growth process and Ag-the sensor anode. The Ag/C sensor can detect a free H2S concentration of 0.041 μM in the E. coli solution. This novel biochemical sensor can monitor the growth behavior of living organisms without damaging them.
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Affiliation(s)
- Chiyako Touge
- Industrial
Technology Center of Fukui Prefecture, 10-61, Kawaiwashizuka,Fukui 910-0102, Japan
| | - Michiyo Nakatsu
- Industrial
Technology Center of Fukui Prefecture, 10-61, Kawaiwashizuka,Fukui 910-0102, Japan
| | - Mai Sugimoto
- Department
of Frontier Fiber and Technology and Science, Graduate School of Engineering, University of Fukui, Bunkyo 3-9-1,Fukui 910-8507, Japan
| | - Eiichiro Takamura
- Department
of Frontier Fiber and Technology and Science, Graduate School of Engineering, University of Fukui, Bunkyo 3-9-1,Fukui 910-8507, Japan
| | - Hiroaki Sakamoto
- Department
of Frontier Fiber and Technology and Science, Graduate School of Engineering, University of Fukui, Bunkyo 3-9-1,Fukui 910-8507, Japan
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2
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Nisar MA, Ross KE, Brown MH, Bentham R, Best G, Whiley H. Detection and quantification of viable but non-culturable Legionella pneumophila from water samples using flow cytometry-cell sorting and quantitative PCR. Front Microbiol 2023; 14:1094877. [PMID: 36793878 PMCID: PMC9922708 DOI: 10.3389/fmicb.2023.1094877] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/03/2023] [Indexed: 02/03/2023] Open
Abstract
Legionella pneumophila is a waterborne pathogen and, as the causative agent of Legionnaires' disease, a significant public health concern. Exposure to environmental stresses, and disinfection treatments, promotes the formation of resistant and potentially infectious viable but non-culturable (VBNC) Legionella. The management of engineered water systems to prevent Legionnaires' disease is hindered by the presence of VBNC Legionella that cannot be detected using the standard culture (ISO11731:2017-05) and quantitative polymerase reaction (ISO/TS12869:2019) methods. This study describes a novel method to quantify VBNC Legionella from environmental water samples using a "viability based flow cytometry-cell sorting and qPCR" (VFC + qPCR) assay. This protocol was then validated by quantifying the VBNC Legionella genomic load from hospital water samples. The VBNC cells were unable to be cultured on Buffered Charcoal Yeast Extract (BCYE) agar; however, their viability was confirmed through their ATP activity and ability to infect amoeba hosts. Subsequently, an assessment of the ISO11731:2017-05 pre-treatment procedure demonstrated that acid or heat treatment cause underestimation of alive Legionella population. Our results showed that these pre-treatment procedures induce culturable cells to enter a VBNC state. This may explain the observed insensitivity and lack of reproducibility often observed with the Legionella culture method. This study represents the first time that flow cytometry-cell sorting in conjunction with a qPCR assay has been used as a rapid and direct method to quantify VBNC Legionella from environmental sources. This will significantly improve future research evaluating Legionella risk management approaches for the control of Legionnaires' disease.
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Affiliation(s)
- Muhammad Atif Nisar
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Kirstin E. Ross
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Melissa H. Brown
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Richard Bentham
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Giles Best
- College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia,Flow Cytometry Facility, Flinders University, Bedford Park, SA, Australia
| | - Harriet Whiley
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia,*Correspondence: Harriet Whiley, ✉
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3
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Nisar MA, Ross KE, Brown MH, Bentham R, Hinds J, Whiley H. Molecular screening and characterization of Legionella pneumophila associated free-living amoebae in domestic and hospital water systems. WATER RESEARCH 2022; 226:119238. [PMID: 36270142 DOI: 10.1016/j.watres.2022.119238] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/05/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
Free-living amoebae are ubiquitous in the environment and cause both opportunistic and non-opportunistic infections in humans. Some genera of amoebae are natural reservoirs of opportunistic plumbing pathogens, such as Legionella pneumophila. In this study, the presence of free-living amoebae and Legionella was investigated in 140 water and biofilm samples collected from Australian domestic (n = 68) and hospital water systems (n = 72). Each sample was screened in parallel using molecular and culture-based methods. Direct quantitative polymerase chain reaction (qPCR) assays showed that 41% samples were positive for Legionella, 33% for L. pneumophila, 11% for Acanthamoeba, and 55% for Vermamoeba vermiformis gene markers. Only 7% of samples contained culturable L. pneumophila serogroup (sg)1, L. pneumophila sg2-14, and non-pneumophila Legionella. In total, 69% of samples were positive for free-living amoebae using any method. Standard culturing found that 41% of the samples were positive for amoeba (either Acanthamoeba, Allovahlkampfia, Stenamoeba, or V. vermiformis). V. vermiformis showed the highest overall frequency of occurrence. Acanthamoeba and V. vermiformis isolates demonstrated high thermotolerance and osmotolerance and strong broad spectrum bacteriogenic activity against Gram-negative and Gram-positive bacteria. Importantly, all Legionella positive samples were also positive for amoeba, and this co-occurrence was statistically significant (p < 0.05). According to qPCR and fluorescence in situ hybridization, V. vermiformis and Allovahlkampfia harboured intracellular L. pneumophila. To our knowledge, this is the first time Allovahlkampfia and Stenamoeba have been demonstrated as hosts of L. pneumophila in potable water. These results demonstrate the importance of amoebae in engineered water systems, both as a pathogen and as a reservoir of Legionella. The high frequency of gymnamoebae detected in this study from Australian engineered water systems identifies an issue of significant public health concern. Future water management protocols should incorporate treatments strategies to control amoebae to reduce the risk to end users.
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Affiliation(s)
- Muhammad Atif Nisar
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Kirstin E Ross
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Melissa H Brown
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Richard Bentham
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Jason Hinds
- Enware Australia Pty Ltd, Caringbah, NSW, Australia
| | - Harriet Whiley
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia.
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Use of a Novel DNA-Loaded Alginate-Calcium Carbonate Biopolymer Surrogate to Study the Engulfment of Legionella pneumophila by Acanthamoeba polyphaga in Water Systems. Microbiol Spectr 2022; 10:e0221022. [PMID: 35950853 PMCID: PMC9430812 DOI: 10.1128/spectrum.02210-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The engulfment of Legionella pneumophila by free-living amoebae (FLA) in engineered water systems (EWS) enhances L. pneumophila persistence and provides a vehicle for rapid replication and increased public health risk. Despite numerous legionellosis outbreaks worldwide, effective tools for studying interactions between L. pneumophila and FLA in EWS are lacking. To address this, we have developed a biopolymer surrogate with a similar size, shape, surface charge, and hydrophobicity to those of stationary-phase L. pneumophila. Parallel experiments were conducted to observe the engulfment of L. pneumophila and the surrogate by Acanthamoeba polyphaga in dechlorinated, filter-sterilised tap water at 30°C for 72 h. Trophozoites engulfed both the surrogate and L. pneumophila, reaching maximum uptake after 2 and 6 h, respectively, but the peak surrogate uptake was ~2-log lower. Expulsion of the engulfed surrogate from A. polyphaga was also faster compared to that of L. pneumophila. Confocal laser scanning microscopy confirmed that the surrogate was actively engulfed and maintained within vacuoles for several hours before being expelled. L. pneumophila and surrogate phagocytosis appear to follow similar pathways, suggesting that the surrogate can be developed as a useful tool for studying interactions between L. pneumophila and FLA in EWS. IMPORTANCE The internalization of L. pneumophila within amoebae is a critical component of their life cycle in EWS, as it protects the bacteria from commonly used water disinfectants and provides a niche for their replication. Intracellularly replicated forms of L. pneumophila are also more virulent and resistant to sanitizers. Most importantly, the bacteria’s adaptation to the intracellular environments of amoebae primes them for the infection of human macrophages, posing a significant public health risk in EWS. The significance of our study is that a newly developed L. pneumophila biopolymer surrogate can mimic the L. pneumophila engulfment process in A. polyphaga, a free-living amoeba. With further development, the surrogate has the potential to improve the understanding of amoeba-mediated L. pneumophila persistence in EWS and the associated public health risk management.
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Kanatani JI, Watahiki M, Kimata K, Kato T, Uchida K, Kura F, Amemura-Maekawa J, Isobe J. Detection of Legionella species, the influence of precipitation on the amount of Legionella DNA, and bacterial microbiome in aerosols from outdoor sites near asphalt roads in Toyama Prefecture, Japan. BMC Microbiol 2021; 21:215. [PMID: 34273946 PMCID: PMC8285874 DOI: 10.1186/s12866-021-02275-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 07/08/2021] [Indexed: 11/29/2022] Open
Abstract
Background Legionellosis is caused by the inhalation of aerosolized water contaminated with Legionella bacteria. In this study, we investigated the prevalence of Legionella species in aerosols collected from outdoor sites near asphalt roads, bathrooms in public bath facilities, and other indoor sites, such as buildings and private homes, using amoebic co-culture, quantitative PCR, and 16S rRNA gene amplicon sequencing. Results Legionella species were not detected by amoebic co-culture. However, Legionella DNA was detected in 114/151 (75.5%) air samples collected near roads (geometric mean ± standard deviation: 1.80 ± 0.52 log10 copies/m3), which was comparable to the numbers collected from bathrooms [15/21 (71.4%), 1.82 ± 0.50] but higher than those collected from other indoor sites [11/30 (36.7%), 0.88 ± 0.56] (P < 0.05). The amount of Legionella DNA was correlated with the monthly total precipitation (r = 0.56, P < 0.01). It was also directly and inversely correlated with the daily total precipitation for seven days (r = 0.21, P = 0.01) and one day (r = − 0.29, P < 0.01) before the sampling day, respectively. 16S rRNA gene amplicon sequencing revealed that Legionella species were detected in 9/30 samples collected near roads (mean proportion of reads, 0.11%). At the species level, L. pneumophila was detected in 2/30 samples collected near roads (the proportion of reads, 0.09 and 0.11% of the total reads number in each positive sample). The three most abundant bacterial genera in the samples collected near roads were Sphingomonas, Streptococcus, and Methylobacterium (mean proportion of reads; 21.1%, 14.6%, and 1.6%, respectively). In addition, the bacterial diversity in outdoor environment was comparable to that in indoor environment which contains aerosol-generating features and higher than that in indoor environment without the features. Conclusions DNA from Legionella species was widely present in aerosols collected from outdoor sites near asphalt roads, especially during the rainy season. Our findings suggest that there may be a risk of exposure to Legionella species not only in bathrooms but also in the areas surrounding asphalt roads. Therefore, the possibility of contracting legionellosis in daily life should be considered. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02275-2.
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Affiliation(s)
- Jun-Ichi Kanatani
- Department of Bacteriology, Toyama Institute of Health, 17-1 Nakataikoyama, 939-0363, Imizu-city, Toyama, Japan.
| | - Masanori Watahiki
- Department of Bacteriology, Toyama Institute of Health, 17-1 Nakataikoyama, 939-0363, Imizu-city, Toyama, Japan
| | - Keiko Kimata
- Department of Bacteriology, Toyama Institute of Health, 17-1 Nakataikoyama, 939-0363, Imizu-city, Toyama, Japan
| | - Tomoko Kato
- Department of Bacteriology, Toyama Institute of Health, 17-1 Nakataikoyama, 939-0363, Imizu-city, Toyama, Japan
| | - Kaoru Uchida
- Department of Bacteriology, Toyama Institute of Health, 17-1 Nakataikoyama, 939-0363, Imizu-city, Toyama, Japan
| | - Fumiaki Kura
- Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, 162-8640, Tokyo, Japan
| | - Junko Amemura-Maekawa
- Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, 162-8640, Tokyo, Japan
| | - Junko Isobe
- Department of Bacteriology, Toyama Institute of Health, 17-1 Nakataikoyama, 939-0363, Imizu-city, Toyama, Japan
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Chen J, Wei H, Fang X, Cai Y, Zhang Z, Wang Y, Lin J, Zhang W, Zhong G. A pragmatic eLCR for an ultrasensitive detection of methicillin-resistant Staphylococcus aureus in joint synovial fluid: superior to qPCR. Analyst 2021; 146:3500-3509. [PMID: 33885074 DOI: 10.1039/d1an00350j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
For periprosthetic joint infection (PJI) patients, an early and rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) in joint synovial fluid is of great significance for receiving timely treatment and avoiding side effects. In clinical practice, the methods for detecting MRSA include the culture-based method and the PCR-based mecA gene detection method with fluorescent readout. However, the culture-based method requires up to 3-7 days for incubation and elaborative screening. The PCR-based molecular diagnosis, due to its high sensitivity, improves the detection time but sacrifices cost and gives false-positive results. Herein, a ligation chain reaction (LCR)-based electrochemical biosensor was developed to detect the mecA of MRSA with the advantages of rapidity, accuracy and low cost. In this system, an integrated dsDNA labeled with thiol and biotin at both terminals is generated only in the presence of the target DNA after LCR, followed by immobilization of the integrated dsDNAs on the bovine serum albumin (BSA)-coated gold electrode, and then the streptavidin horseradish peroxidase (SA-HRPs) is specifically bound to the biotin labels via biotin-streptavidin interaction, generating the catalytic amperometric readout. Impressively, the developed method achieved the detection of rare mecA in the joint synovial fluid of PJI patients (417-666 copies as quantified by qPCR). The proposed electrochemistry-based method is highly convenient for the point-of-care testing and was comparable with PCR in sensitivity, but superior in selectivity (single-base differentiation) and cost (nanomolar DNA probe consumption and simple device), demonstrating its huge potential in clinical applications for MRSA diagnosis.
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Affiliation(s)
- Jinyuan Chen
- The Central Laboratory, Fujian Key Laboratory of Precision Medicine for Cancer, the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China and Key Laboratory of Radiation Biology of Fujian higher education institutions, the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Hongxiang Wei
- Department of Orthopaedics, Fujian Provincial Institute of Orthopaedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China.
| | - Xinyu Fang
- Department of Orthopaedics, Fujian Provincial Institute of Orthopaedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China.
| | - Yuanqing Cai
- Department of Orthopaedics, Fujian Provincial Institute of Orthopaedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China.
| | - Zhenzhen Zhang
- Department of Phthology, the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China
| | - Yunqing Wang
- Department of Orthopaedics, Fujian Provincial Institute of Orthopaedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China.
| | - Jianhua Lin
- Department of Orthopaedics, Fujian Provincial Institute of Orthopaedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China.
| | - Wenming Zhang
- Department of Orthopaedics, Fujian Provincial Institute of Orthopaedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China.
| | - Guangxian Zhong
- Department of Orthopaedics, Fujian Provincial Institute of Orthopaedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China.
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Moreno Y, Moreno-Mesonero L, García-Hernández J. DVC-FISH to identify potentially pathogenic Legionella inside free-living amoebae from water sources. ENVIRONMENTAL RESEARCH 2019; 176:108521. [PMID: 31195295 DOI: 10.1016/j.envres.2019.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/11/2019] [Accepted: 06/01/2019] [Indexed: 06/09/2023]
Abstract
Despite all safety efforts, drinking and wastewater can still be contaminated by Legionella and free-living amoebae (FLA) since these microorganisms are capable of resisting disinfection treatments. An amoebae cyst harboring pathogenic Legionella spp. can be a transporter of this organism, protecting it and enhancing its infection abilities. Therefore, the aim of this work is to identify by DVC-FISH viable Legionella spp and Legionella pneumophila cells inside FLA from water sources in a specific and rapid way with the aim of assessing the real risk of these waters. A total of 55 water samples were processed, 30 reclaimed wastewater and 25 drinking water. FLA presence was detected in 52.7% of the total processed water samples. When DVC-FISH technique was applied, the presence of viable internalized Legionella spp. cells was identified in 69.0% of the total FLA-positive samples, concretely in 70.0% and 66.7% of wastewater and drinking water samples, respectively. L. pneumophila was simultaneously identified in 48.3% of the total FLA-positive samples, specifically in 50.0% and 44.4% of wastewater and drinking water samples, respectively. By culture, potentially pathogenic Legionella cells were recovered in 27.6% of the total FLA-positive bacteria, particularly in 35.0% and 11.1% of wastewater and drinking water samples, respectively. These findings demonstrate that FLA may promote resistance of bacteria to the performed disinfection treatments for drinking as well as for wastewater. So, in addition to the risk for the presence of pathogenic FLA in water it is necessary to take into account that these can be transporters of the pathogenic bacteria Legionella, which are able to survive inside them. The DVC-FISH method described here has been proved to be a rapid and specific tool to identify pathogenic Legionella spp. and L. penumophila viable cells harboured by FLA in these water sources, posing particular public health concern.
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Affiliation(s)
- Y Moreno
- Research Institute of Water and Environmental Ingeneering (IIAMA), Universitat Politècnica de València, 46022 Valencia, Spain.
| | - L Moreno-Mesonero
- Research Institute of Water and Environmental Ingeneering (IIAMA), Universitat Politècnica de València, 46022 Valencia, Spain
| | - J García-Hernández
- Biotechnology Department, Universitat Politècnica de València, 46022 Valencia, Spain
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Detection of Legionella Anisa in Water from Hospital Dental Chair Units and Molecular Characterization by Whole-Genome Sequencing. Microorganisms 2018; 6:microorganisms6030071. [PMID: 30021964 PMCID: PMC6165070 DOI: 10.3390/microorganisms6030071] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/13/2018] [Accepted: 07/16/2018] [Indexed: 11/25/2022] Open
Abstract
This study aims to assess contamination with Legionella spp. in water from dental chair units (DCUs) of a hospital dental ward and to perform its molecular characterization by whole-genome sequencing (WGS). We collect eight water samples (250 mL) from four DCUs (sink and water-syringe). Samples are tested for the presence of Legionella spp. (CFUs/mL) by culturing according to the Nederland Norm (NEN) 6265. Three DCUs are found positive for Legionella anisa, and four isolates are cultured (sink n = 2, water-syringe n = 1; two isolates from the same chair) with 1 × 102 CFU/mL. Whole-genome multi-locus sequence typing (wgMLST) results indicate that all strains belong to the same cluster with two to four allele differences. Classical culture combined with WGS allows the identification of a unique clone of L. anisa in several DCUs in the same hospital dental ward. This may indicate a common contamination source in the dental unit waterlines, which was fixed by replacing the chairs and main pipeline of the unit. Our results reveal tap water contamination in direct contact with patients and the usefulness of WGS to investigate bacterial molecular epidemiology.
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Adaptation of Amoeba Plate Test To Recover Legionella Strains from Clinical Samples. J Clin Microbiol 2018; 56:JCM.01361-17. [PMID: 29467193 DOI: 10.1128/jcm.01361-17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 02/12/2018] [Indexed: 11/20/2022] Open
Abstract
The isolation of Legionella from respiratory samples is the gold standard for diagnosis of Legionnaires' disease (LD) and enables epidemiological studies and outbreak investigations. The purpose of this work was to adapt and to evaluate the performance of an amoebic coculture procedure (the amoeba plate test [APT]) for the recovery of Legionella strains from respiratory samples, in comparison with axenic culture and liquid-based amoebic coculture (LAC). Axenic culture, LAC, and APT were prospectively performed with 133 respiratory samples from patients with LD. The sensitivities and times to results for the three techniques were compared. Using the three techniques, Legionella strains were isolated in 46.6% (n = 62) of the 133 respiratory samples. The sensitivity of axenic culture was 42.9% (n = 57), that of LAC was 30.1% (n = 40), and that of APT was 36.1% (n = 48). Seven samples were positive by axenic culture only; for those samples, there were <10 colonies in total. Five samples, all sputum samples, were positive by an amoebic procedure only (5/5 samples by APT and 2/5 samples by LAC); all had overgrowth by oropharyngeal flora with axenic culture. The combination of axenic culture with APT yielded a maximal isolation rate (i.e., 46.6%). Overall, the APT significantly reduced the median time for Legionella identification to 4 days, compared with 7 days for LAC (P < 0.0001). The results of this study support the substitution of LAC by APT, which could be implemented as a second-line technique for culture-negative samples and samples with microbial overgrowth, especially sputum samples. The findings provide a logical basis for further studies in both clinical and environmental settings.
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10
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Xu L, Liang W, Wen Y, Wang L, Yang X, Ren S, Jia N, Zuo X, Liu G. An ultrasensitive electrochemical biosensor for the detection of mecA gene in methicillin-resistant Staphylococcus aureus. Biosens Bioelectron 2017; 99:424-430. [PMID: 28810233 DOI: 10.1016/j.bios.2017.08.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/03/2017] [Accepted: 08/07/2017] [Indexed: 10/19/2022]
Abstract
Electrochemical DNA biosensor has unique advantages for on-site pathogenic microorganism detection, yet the detection of long DNA towards genome DNA (gDNA) analysis remains challenge. In this work, we report a novel electrochemical biosensor for the ultrasensitive analysis of mecA DNA on methicillin-resistant Staphylococcus aureus (MRSA) genome, using a multi-signal probes (MSP) system. The MSP consists of 7 biotin-labelled signal probes that will combine to the target DNA in a prehybridization step, and then the complex will be captured by a DNA tetrahedron structure probe (TSP) on the electrode surface. Then, after the introduction of the streptavidin-labelled HRP enzyme, a catalysis current signal is detected that is found to be corresponding to the concentration of the target DNA. MSP in this work plays a critical role not only for the signal amplification through bringing 7 biotins, but also dramatically improves the accessibility of the target sequence embedded in the double-strand DNA molecules and complex second structures. The 3-D DNA TSP here provides steady support and optimized surface density for the very "large" complex of MSP system and gDNA, as a base of the capture probe. Finally, as low as 10fM synthetic target DNA was successfully detected, which is at least 3 magnitudes lower than that using single signal probe. Most importantly, we demonstrated the practicability of our analysis method by analyzing a 57fM MRSA gDNA sample showing excellent selectivity, and the reliability of the analysis was also demonstrated by digital PCR.
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Affiliation(s)
- Li Xu
- Laboratory of biometrology, Shanghai Institute of Measurement and Testing Technology, Shanghai 201203, PR China
| | - Wen Liang
- Laboratory of biometrology, Shanghai Institute of Measurement and Testing Technology, Shanghai 201203, PR China
| | - Yanli Wen
- Laboratory of biometrology, Shanghai Institute of Measurement and Testing Technology, Shanghai 201203, PR China
| | - Lele Wang
- Laboratory of biometrology, Shanghai Institute of Measurement and Testing Technology, Shanghai 201203, PR China
| | - Xue Yang
- Department of Chemistry, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, PR China
| | - Shuzhen Ren
- Laboratory of biometrology, Shanghai Institute of Measurement and Testing Technology, Shanghai 201203, PR China
| | - Nengqin Jia
- Department of Chemistry, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, PR China
| | - Xiaolei Zuo
- Division of Physical Biology&Bioimaging Center, Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, PR China
| | - Gang Liu
- Laboratory of biometrology, Shanghai Institute of Measurement and Testing Technology, Shanghai 201203, PR China.
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11
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Montagna MT, De Giglio O, Cristina ML, Napoli C, Pacifico C, Agodi A, Baldovin T, Casini B, Coniglio MA, D'Errico MM, Delia SA, Deriu MG, Guida M, Laganà P, Liguori G, Moro M, Mura I, Pennino F, Privitera G, Romano Spica V, Sembeni S, Spagnolo AM, Tardivo S, Torre I, Valeriani F, Albertini R, Pasquarella C. Evaluation of Legionella Air Contamination in Healthcare Facilities by Different Sampling Methods: An Italian Multicenter Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017. [PMID: 28640202 PMCID: PMC5551108 DOI: 10.3390/ijerph14070670] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Healthcare facilities (HF) represent an at-risk environment for legionellosis transmission occurring after inhalation of contaminated aerosols. In general, the control of water is preferred to that of air because, to date, there are no standardized sampling protocols. Legionella air contamination was investigated in the bathrooms of 11 HF by active sampling (Surface Air System and Coriolis®μ) and passive sampling using settling plates. During the 8-hour sampling, hot tap water was sampled three times. All air samples were evaluated using culture-based methods, whereas liquid samples collected using the Coriolis®μ were also analyzed by real-time PCR. Legionella presence in the air and water was then compared by sequence-based typing (SBT) methods. Air contamination was found in four HF (36.4%) by at least one of the culturable methods. The culturable investigation by Coriolis®μ did not yield Legionella in any enrolled HF. However, molecular investigation using Coriolis®μ resulted in eight HF testing positive for Legionella in the air. Comparison of Legionella air and water contamination indicated that Legionella water concentration could be predictive of its presence in the air. Furthermore, a molecular study of 12 L. pneumophila strains confirmed a match between the Legionella strains from air and water samples by SBT for three out of four HF that tested positive for Legionella by at least one of the culturable methods. Overall, our study shows that Legionella air detection cannot replace water sampling because the absence of microorganisms from the air does not necessarily represent their absence from water; nevertheless, air sampling may provide useful information for risk assessment. The liquid impingement technique appears to have the greatest capacity for collecting airborne Legionella if combined with molecular investigations.
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Affiliation(s)
- Maria Teresa Montagna
- Department of Biomedical Science and Human Oncology, University of Bari "Aldo Moro", Piazza G. Cesare 11, 70124 Bari, Italy.
| | - Osvalda De Giglio
- Department of Biomedical Science and Human Oncology, University of Bari "Aldo Moro", Piazza G. Cesare 11, 70124 Bari, Italy.
| | - Maria Luisa Cristina
- Department of Health Sciences, University of Genoa, Via Pastore 1, 16132 Genova, Italy.
| | - Christian Napoli
- Department of Medical and Surgical Sciences and Translational Medicine, Sapienza University of Roma, Via di Grottarossa 1035, 00189 Roma, Italy.
| | - Claudia Pacifico
- Department of Biomedical Science and Human Oncology, University of Bari "Aldo Moro", Piazza G. Cesare 11, 70124 Bari, Italy.
| | - Antonella Agodi
- Department of Medical and Surgical Sciences and Advanced Technologies "GF Ingrassia", University of Catania, Via Sofia 87, 95123 Catania, Italy.
| | - Tatjana Baldovin
- Department of Cardiac, Thoracic and Vascular Sciences, Hygiene and Public Health Unit, University of Padova, Via Loredan 18, 35131 Padova, Italy.
| | - Beatrice Casini
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via San Zeno 35/39, 56127 Pisa, Italy.
| | - Maria Anna Coniglio
- Department of Medical and Surgical Sciences and Advanced Technologies "GF Ingrassia", University of Catania, Via Sofia 87, 95123 Catania, Italy.
| | - Marcello Mario D'Errico
- Department of Biomedical Sciences and Public Health, Polytechnic University of Marche, via Tronto, 10/a Torrette di Ancona, 60020 Ancona, Italy.
| | - Santi Antonino Delia
- Department of Biomedical Science and Morphological and Functional Images, University of Messina, Via C.Valeria snc, 98125 Messina, Italy.
| | - Maria Grazia Deriu
- Department of Biomedical Science-Hygiene Section, University of Sassari, Via Padre Manzella 4, 07100 Sassari, Italy.
| | - Marco Guida
- Department of Biology, University of Napoli "Federico II", Via Cinthia 26, 80126 Napoli, Italy.
| | - Pasqualina Laganà
- Department of Biomedical Science and Morphological and Functional Images, University of Messina, Via C.Valeria snc, 98125 Messina, Italy.
| | - Giorgio Liguori
- Department of Movement Sciences and Wellbeing, University "Parthenope", Via Medina 40, 80133 Napoli, Italy.
| | - Matteo Moro
- IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
| | - Ida Mura
- Department of Biomedical Science-Hygiene Section, University of Sassari, Via Padre Manzella 4, 07100 Sassari, Italy.
| | - Francesca Pennino
- Department of Public Health, University of Napoli "Federico II", Via S.Pansini 5, 80131 Napoli, Italy.
| | - Gaetano Privitera
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via San Zeno 35/39, 56127 Pisa, Italy.
| | - Vincenzo Romano Spica
- Department of Movement, Human and Health Sciences, Public Health Unit, University of Roma "Foro Italico", P.zza Lauro De Bosis 6, 00135 Roma, Italy.
| | - Silvia Sembeni
- Department of Diagnostic and Public Health, University of Verona, Strada le Grazie 8, 37134 Verona, Italy.
| | - Anna Maria Spagnolo
- Department of Health Sciences, University of Genoa, Via Pastore 1, 16132 Genova, Italy.
| | - Stefano Tardivo
- Department of Diagnostic and Public Health, University of Verona, Strada le Grazie 8, 37134 Verona, Italy.
| | - Ida Torre
- Department of Public Health, University of Napoli "Federico II", Via S.Pansini 5, 80131 Napoli, Italy.
| | - Federica Valeriani
- Department of Movement, Human and Health Sciences, Public Health Unit, University of Roma "Foro Italico", P.zza Lauro De Bosis 6, 00135 Roma, Italy.
| | - Roberto Albertini
- Department of Medicine and Surgery, University of Parma, Medical Immunology Unit, University Hospital of Parma, Via Gramsci 14, 43126 Parma, Italy.
| | - Cesira Pasquarella
- Department of Medicine and Surgery, University of Parma, Via Volturno 39, 43125 Parma, Italy.
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Wang H, Bédard E, Prévost M, Camper AK, Hill VR, Pruden A. Methodological approaches for monitoring opportunistic pathogens in premise plumbing: A review. WATER RESEARCH 2017; 117:68-86. [PMID: 28390237 PMCID: PMC5693313 DOI: 10.1016/j.watres.2017.03.046] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/19/2017] [Accepted: 03/22/2017] [Indexed: 05/06/2023]
Abstract
Opportunistic premise (i.e., building) plumbing pathogens (OPPPs, e.g., Legionella pneumophila, Mycobacterium avium complex, Pseudomonas aeruginosa, Acanthamoeba, and Naegleria fowleri) are a significant and growing source of disease. Because OPPPs establish and grow as part of the native drinking water microbiota, they do not correspond to fecal indicators, presenting a major challenge to standard drinking water monitoring practices. Further, different OPPPs present distinct requirements for sampling, preservation, and analysis, creating an impediment to their parallel detection. The aim of this critical review is to evaluate the state of the science of monitoring OPPPs and identify a path forward for their parallel detection and quantification in a manner commensurate with the need for reliable data that is informative to risk assessment and mitigation. Water and biofilm sampling procedures, as well as factors influencing sample representativeness and detection sensitivity, are critically evaluated with respect to the five representative bacterial and amoebal OPPPs noted above. Available culturing and molecular approaches are discussed in terms of their advantages, limitations, and applicability. Knowledge gaps and research needs towards standardized approaches are identified.
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Affiliation(s)
- Hong Wang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| | - Emilie Bédard
- Department of Civil Engineering, Polytechnique Montreal, Montreal, QC, Canada
| | - Michèle Prévost
- Department of Civil Engineering, Polytechnique Montreal, Montreal, QC, Canada
| | - Anne K Camper
- Center for Biofilm Engineering and Department of Civil Engineering, Montana State University, Bozeman, MT 59717, USA
| | - Vincent R Hill
- Waterborne Disease Prevention Branch, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30329, USA
| | - Amy Pruden
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA 24061, USA
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Temperature-Dependent Growth Modeling of Environmental and Clinical Legionella pneumophila Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) Genotypes. Appl Environ Microbiol 2017; 83:AEM.03295-16. [PMID: 28159784 DOI: 10.1128/aem.03295-16] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 01/25/2017] [Indexed: 01/02/2023] Open
Abstract
Legionella pneumophila causes waterborne infections resulting in severe pneumonia. High-resolution genotyping of L. pneumophila isolates can be achieved by multiple-locus variable-number tandem-repeat analysis (MLVA). Recently, we found that different MLVA genotypes of L. pneumophila dominated different sites in a small drinking-water network, with a genotype-related temperature and abundance regime. The present study focuses on understanding the temperature-dependent growth kinetics of the genotypes that dominated the water network. Our aim was to model mathematically the influence of temperature on the growth kinetics of different environmental and clinical L. pneumophila genotypes and to compare it with the influence of their ecological niches. Environmental strains showed a distinct temperature preference, with significant differences among the growth kinetics of the three studied genotypes (Gt4, Gt6, and Gt15). Gt4 strains exhibited superior growth at lower temperatures (25 and 30°C), while Gt15 strains appeared to be best adapted to relatively higher temperatures (42 and 45°C). The temperature-dependent growth traits of the environmental genotypes were consistent with their distribution and temperature preferences in the water network. Clinical isolates exhibited significantly higher growth rates and reached higher maximal cell densities at 37°C and 42°C than the environmental strains. Further research on the growth preferences of L. pneumophila clinical and environmental genotypes will result in a better understanding of their ecological niches in drinking-water systems as well as in the human body.IMPORTANCELegionella pneumophila is a waterborne pathogen that threatens humans in developed countries. The bacteria inhabit natural and man-made freshwater environments. Here we demonstrate that different environmental L. pneumophila genotypes have different temperature-dependent growth kinetics. Moreover, Legionella strains that belong to the same species but were isolated from environmental and clinical sources possess adaptations for growth at different temperatures. These growth preferences may influence the bacterial colonization at specific ecological niches within the drinking-water network. Adaptations for growth at human body temperatures may facilitate the abilities of some L. pneumophila strains to infect and cause illness in humans. Our findings may be used as a tool to improve Legionella monitoring in drinking-water networks. Risk assessment models for predicting the risk of legionellosis should take into account not only Legionella concentrations but also the temperature-dependent growth kinetics of the isolates.
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An Electrochemical DNA Sensing System Using Modified Nanoparticle Probes for Detecting Methicillin-Resistant Staphylococcus aureus. Methods Mol Biol 2017. [PMID: 28299678 DOI: 10.1007/978-1-4939-6911-1_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
We have developed a novel, highly sensitive, biosensing system for detecting methicillin-resistant Staphylococcus aureus (MRSA). The system employs gold nanoparticles (AuNPs), magnetic nanoparticles (mNPs), and an electrochemical detection method. We have designed and synthesized ferrocene- and single-stranded DNA-conjugated nanoparticles that hybridize to MRSA DNA. Hybridized complexes are easily separated by taking advantage of mNPs. A current response could be obtained through the oxidation of ferrocene on the AuNP surface when a constant potential of +250 mV vs. Ag/AgCl is applied. The enzymatic reaction of L-proline dehydrogenase provides high signal amplification. This sensing system, using a nanoparticle-modified probe, has the ability to detect 10 pM of genomic DNA from MRSA without amplification by the polymerase chain reaction. Current responses are linearly related to the amount of genomic DNA in the range of 10-166 pM. Selectivity is confirmed by demonstrating that this sensing system could distinguish MRSA from Staphylococcus aureus (SA) DNA.
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Dobrowsky PH, Khan S, Cloete TE, Khan W. Molecular detection of Acanthamoeba spp., Naegleria fowleri and Vermamoeba (Hartmannella) vermiformis as vectors for Legionella spp. in untreated and solar pasteurized harvested rainwater. Parasit Vectors 2016; 9:539. [PMID: 27724947 PMCID: PMC5057267 DOI: 10.1186/s13071-016-1829-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/02/2016] [Indexed: 01/01/2023] Open
Abstract
Background Legionella spp. employ multiple strategies to adapt to stressful environments including the proliferation in protective biofilms and the ability to form associations with free-living amoeba (FLA). The aim of the current study was to identify Legionella spp., Acanthamoeba spp., Vermamoeba (Hartmannella) vermiformis and Naegleria fowleri that persist in a harvested rainwater and solar pasteurization treatment system. Methods Pasteurized (45 °C, 65 °C, 68 °C, 74 °C, 84 °C and 93 °C) and unpasteurized tank water samples were screened for Legionella spp. and the heterotrophic plate count was enumerated. Additionally, ethidium monoazide quantitative polymerase chain reaction (EMA-qPCR) was utilized for the quantification of viable Legionella spp., Acanthamoeba spp., V. vermiformis and N. fowleri in pasteurized (68 °C, 74 °C, 84 °C and 93 °C) and unpasteurized tank water samples, respectively. Results Of the 82 Legionella spp. isolated from unpasteurized tank water samples, Legionella longbeachae (35 %) was the most frequently isolated, followed by Legionella norrlandica (27 %) and Legionella rowbothamii (4 %). Additionally, a positive correlation was recorded between the heterotrophic plate count vs. the number of Legionella spp. detected (ρ = 0.710, P = 0.048) and the heterotrophic plate count vs. the number of Legionella spp. isolated (ρ = 0.779, P = 0.0028) from the tank water samples collected. Solar pasteurization was effective in reducing the gene copies of viable V. vermiformis (3-log) and N. fowleri (5-log) to below the lower limit of detection at temperatures of 68–93 °C and 74–93 °C, respectively. Conversely, while the gene copies of viable Legionella and Acanthamoeba were significantly reduced by 2-logs (P = 0.0024) and 1-log (P = 0.0015) overall, respectively, both organisms were still detected after pasteurization at 93 °C. Conclusions Results from this study indicate that Acanthamoeba spp. primarily acts as the vector and aids in the survival of Legionella spp. in the solar pasteurized rainwater as both organisms were detected and were viable at high temperatures (68–93 °C).
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Affiliation(s)
- Penelope H Dobrowsky
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Sehaam Khan
- Faculty of Health and Applied Sciences, Namibia University of Science and Technology, 13 Storch Street, Private Bag 13388, Windhoek, Namibia
| | - Thomas E Cloete
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Wesaal Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
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16
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Dietersdorfer E, Cervero-Aragó S, Sommer R, Kirschner AK, Walochnik J. Optimized methods for Legionella pneumophila release from its Acanthamoeba hosts. BMC Microbiol 2016; 16:74. [PMID: 27113731 PMCID: PMC4845434 DOI: 10.1186/s12866-016-0691-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 04/14/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Free-living amoebae (FLA) and particularly acanthamoebae serve as vehicles and hosts for Legionella pneumophila, among other pathogenic microorganisms. Within the amoebae, L. pneumophila activates a complex regulatory pathway that enables the bacteria to resist amoebal digestion and to replicate. Moreover, the amoebae provide the bacteria protection against harsh environmental conditions and disinfectants commonly used in engineered water systems. To study this ecological relationship, co-culture and infection models have been used. However, there is a lack of data regarding the effectiveness of the different methods used to release intracellular bacteria from their amoebal hosts. The aim of this study was to evaluate the impact of the methods used to release intracellular L. pneumophila cells on the culturability of the bacteria. Furthermore, the standard method ISO 11731:1998 for the recovery and enumeration of Legionella from water samples was evaluated for its suitability to quantify intracellular bacteria. RESULTS The effectiveness of the eight release treatments applied to L. pneumophila and Acanthamoeba strains in a free-living state varied between bacterial strains. Moreover, the current study provides numerical data on the state of co-culture suspensions at different time points. The release treatments enhanced survival of both microorganisms in co-cultures of L. pneumophila and Acanthamoeba. Passage through a needle (21G, 27G) and centrifugation at 10,000 × g showed the highest bacterial counts when releasing the bacteria from the intracellular state. Regarding the ISO 11731:1998 method, one of the tested strains showed no differences between the recovery rates of associated and free-living L. pneumophila. However, a reduced bacterial recovery rate was observed for the second L. pneumophila strain used, and this difference is likely linked to the survival of the amoebae. CONCLUSIONS Mechanical release treatments were the most effective methods for providing bacterial release without the use of chemicals that could compromise further study of the intracellular bacteria. The current results demonstrated that the recovery of L. pneumophila from water systems may be underestimated if protozoal membranes are not disrupted.
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Affiliation(s)
- Elisabeth Dietersdorfer
- Institute of Specific Prophylaxis and Tropical Medicine, Department of Medical Parasitology, Medical University of Vienna, Kinderspitalgasse 15, A-1090, Vienna, Austria
| | - Sílvia Cervero-Aragó
- Institute for Hygiene and Applied Immunology, Water Hygiene, Medical University of Vienna, Kinderspitalgasse 15, A-1090, Vienna, Austria. .,Interuniversity Cooperation Centre for Water & Health, Vienna, Austria.
| | - Regina Sommer
- Institute for Hygiene and Applied Immunology, Water Hygiene, Medical University of Vienna, Kinderspitalgasse 15, A-1090, Vienna, Austria.,Interuniversity Cooperation Centre for Water & Health, Vienna, Austria
| | - Alexander K Kirschner
- Institute for Hygiene and Applied Immunology, Water Hygiene, Medical University of Vienna, Kinderspitalgasse 15, A-1090, Vienna, Austria.,Interuniversity Cooperation Centre for Water & Health, Vienna, Austria
| | - Julia Walochnik
- Institute of Specific Prophylaxis and Tropical Medicine, Department of Medical Parasitology, Medical University of Vienna, Kinderspitalgasse 15, A-1090, Vienna, Austria
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Lu J, Struewing I, Vereen E, Kirby AE, Levy K, Moe C, Ashbolt N. Molecular Detection of Legionella
spp. and their associations with Mycobacterium
spp., Pseudomonas aeruginosa
and amoeba hosts in a drinking water distribution system. J Appl Microbiol 2016; 120:509-21. [DOI: 10.1111/jam.12996] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/08/2015] [Accepted: 10/27/2015] [Indexed: 01/12/2023]
Affiliation(s)
- J. Lu
- U.S. EPA National Exposure Research Laboratory; Cincinnati OH USA
| | | | - E. Vereen
- Center for Global Safe Water; Sanitation and Hygiene; Emory University; Atlanta GA USA
| | - A. E. Kirby
- Center for Global Safe Water; Sanitation and Hygiene; Emory University; Atlanta GA USA
| | - K. Levy
- Center for Global Safe Water; Sanitation and Hygiene; Emory University; Atlanta GA USA
| | - C. Moe
- Center for Global Safe Water; Sanitation and Hygiene; Emory University; Atlanta GA USA
| | - N. Ashbolt
- School of Public Health; University of Alberta; Edmonton AB Canada
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Moreno-Mesonero L, Moreno Y, Alonso JL, Ferrús MA. DVC-FISH and PMA-qPCR techniques to assess the survival of Helicobacter pylori inside Acanthamoeba castellanii. Res Microbiol 2016; 167:29-34. [PMID: 26342651 DOI: 10.1016/j.resmic.2015.08.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 08/13/2015] [Accepted: 08/19/2015] [Indexed: 10/23/2022]
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Magnet A, Peralta RHS, Gomes TS, Izquierdo F, Fernandez-Vadillo C, Galvan AL, Pozuelo MJ, Pelaz C, Fenoy S, Del Águila C. Vectorial role of Acanthamoeba in Legionella propagation in water for human use. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 505:889-895. [PMID: 25461091 DOI: 10.1016/j.scitotenv.2014.10.064] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 10/15/2014] [Accepted: 10/19/2014] [Indexed: 06/04/2023]
Abstract
Legionella spp. is the causative agent of Legionnaires' disease and is transmitted through aerosols emanating from man-made water systems. Legionella resistance to water treatments has been related to its association with environmental amoebae such as Acanthamoeba. Due to the high presence of this protozoon in Spain and the high rate of notification of Legionnaires' disease of this country, the aims of this work were to study the coexistence of these bacteria and protozoa in water as well as their interaction. The usefulness of Acanthamoeba co-culture for the isolation of environmental Legionella was also studied. For this purpose, 70 water samples were collected in 2011 from three Drinking Water Treatment Plants, three Wastewater Treatment Plants and five Natural Pools in Spain. Acanthamoeba was found by PCR in 87.1% (61/70) samples and, by culture in 85.7% (60/70) samples. Legionella was detected by PCR in 58.6% (41/70) of water samples, in 5.7% (4/70) by agar culture and 75.7% (53/70) by Acanthamoeba co-culture. From the 54 Acanthamoeba water isolates, Legionella was detected in 43 of them independently of Acanthamoeba's genotype (T3, T4 and T11). Legionella feeleii, Legionella birminghamiensis, Legionella gresilensis/berliardensis, Legionella fairfieldensis, Legionella drozanski and Legionella falloni were identified. In conclusion, our results showed that environmental Acanthamoeba is infected by Legionella to a high percentage, and due to its ubiquity, high resistance and its pathogenic potential per se, new methods for its elimination should be studied. Also, the high effectivity of Acanthamoeba co-culture for Legionella detection has been shown.
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Affiliation(s)
- A Magnet
- Facultad de Farmacia, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain; Facultad de Medicina, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain
| | - R H S Peralta
- Facultad de Farmacia, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain; Departamento de Patologia, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - T S Gomes
- Facultad de Farmacia, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain; CAPES Foundation, Ministry of Education of Brazil, Brasília, Brazil
| | - F Izquierdo
- Facultad de Farmacia, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain; Facultad de Medicina, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain
| | - C Fernandez-Vadillo
- Facultad de Farmacia, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain
| | - A L Galvan
- Facultad de Farmacia, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain; Escuela de Microbiología, Grupo de Parasitología, Universidad de Antioquia, Medellín, Colombia
| | - M J Pozuelo
- Facultad de Farmacia, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain
| | - C Pelaz
- Laboratorio de Legionella, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - S Fenoy
- Facultad de Farmacia, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain; Facultad de Medicina, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain
| | - C Del Águila
- Facultad de Farmacia, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain; Facultad de Medicina, Universidad San Pablo CEU, Urbanización Montepríncipe, Boadilla del Monte, Madrid, Spain.
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Conza L, Casati Pagani S, Gaia V. Influence of climate and geography on the occurrence of Legionella and amoebae in composting facilities. BMC Res Notes 2014; 7:831. [PMID: 25421541 PMCID: PMC4289342 DOI: 10.1186/1756-0500-7-831] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Accepted: 10/21/2014] [Indexed: 11/10/2022] Open
Abstract
Background The incidence of Legionnaires’ disease (LD) in southern Switzerland is three times higher than in northern Switzerland. Climatic and geographic factors may be potential causes for this difference. We studied the prevalence of Legionella and free-living amoebae (FLA) in compost and bioaerosol in two Swiss regions to understand the role of climate and geography in the transmission of LD. We also tried to investigate whether or not compost storage duration would influence the composition of Legionella and FLA communities. Results A larger proportion of compost heaps in facilities from southern Switzerland harbor more diverse Legionella compared to the north (P = 0.0146). FLA were isolated from composts in northern facilities at slightly higher rates (88.2% vs. 69.2%) and at lower rates from bioaerosols (6.3% vs. 13%) than in southern Switzerland. The diversity of FLA was higher in northern than in southern Switzerland (80% vs. 65%). A general decrease in the presence and variety of species was observed with decreasing compost storage time length. A discriminant model showed that values of vapour pressure, relative humidity and temperature distinguish the two regions, which were also characterised by different contamination rates by FLA and Legionella. Conclusions The duration of outdoor storage may favour contamination of the compost by Legionella, and may increase the number and isolation of Legionella naturally occurring in compost. The climate in the south seems to favour higher Legionella contamination of compost heaps: this could explain the higher incidence of LD in southern Switzerland. Electronic supplementary material The online version of this article (doi:10.1186/1756-0500-7-831) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lisa Conza
- Swiss National Reference Centre for Legionella, Bellinzona, Switzerland.
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Conza L, Pagani SC, Gaia V. Presence of Legionella and free-living Amoebae in composts and bioaerosols from composting facilities. PLoS One 2013; 8:e68244. [PMID: 23844174 PMCID: PMC3699541 DOI: 10.1371/journal.pone.0068244] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Accepted: 05/22/2013] [Indexed: 11/24/2022] Open
Abstract
Several species of Legionella cause Legionnaires' disease (LD). Infection may occur through inhalation of Legionella or amoebal vesicles. The reservoirs of Legionella are water, soil, potting soil and compost. Some species of free-living amoebae (FLA) that are naturally present in water and soil were described as hosts for Legionella. This study aimed to understand whether or not the composting facilities could be sources of community-acquired Legionella infections after development of bioaerosols containing Legionella or FLA. We looked for the presence of Legionella (by co-culture) and FLA (by culture) in composts and bioaerosols collected at four composting facilities located in southern Switzerland. We investigated the association between the presence of Legionella and compost and air parameters and presence of FLA. Legionella spp. (including L. pneumophila) were detected in 69.3% (61/88) of the composts and FLA (mainly Acanthamoeba, Vermamoeba, Naegleria and Stenamoeba) in 92.0% (81/88). L. pneumophila and L. bozemanii were most frequently isolated. FLA as potential host for Legionella spp. were isolated from 40.9% (36/88) of the composts in all facilities. In Legionella-positive samples the temperature of compost was significantly lower (P = 0.012) than in Legionella-negative samples. Of 47 bioaerosol samples, 19.1% (9/47) were positive for FLA and 10.6% (5/47) for L. pneumophila. Composts (62.8%) were positive for Legionella and FLA contemporaneously, but both microorganisms were never detected simultaneously in bioaerosols. Compost can release bioaerosol containing FLA or Legionella and could represent a source of infection of community-acquired Legionella infections for workers and nearby residents.
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Affiliation(s)
- Lisa Conza
- Swiss National Reference Centre for Legionella, Cantonal Institute of Microbiology, Bellinzona, Switzerland.
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