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Characterization of bacterial communities in wastewater with enhanced taxonomic resolution by full-length 16S rRNA sequencing. Sci Rep 2019; 9:9673. [PMID: 31273307 PMCID: PMC6609626 DOI: 10.1038/s41598-019-46015-z] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 06/21/2019] [Indexed: 12/22/2022] Open
Abstract
Wastewater treatment is crucial to environmental hygiene in urban environments. However, wastewater treatment plants (WWTPs) collect chemicals, organic matter, and microorganisms including pathogens and multi-resistant bacteria from various sources which may be potentially released into the environment via WWTP effluent. To better understand microbial dynamics in WWTPs, we characterized and compared the bacterial community of the inflow and effluent of a WWTP in Berlin, Germany using full-length 16S rRNA gene sequences, which allowed for species level determination in many cases and generally resolved bacterial taxa. Significantly distinct bacterial communities were identified in the wastewater inflow and effluent samples. Dominant operational taxonomic units (OTUs) varied both temporally and spatially. Disease associated bacterial groups were efficiently reduced in their relative abundance from the effluent by the WWTP treatment process, except for Legionella and Leptospira species which demonstrated an increase in relative proportion from inflow to effluent. This indicates that WWTPs, while effective against enteric bacteria, may enrich and release other potentially pathogenic bacteria into the environment. The taxonomic resolution of full-length 16S rRNA genes allows for improved characterization of potential pathogenic taxa and other harmful bacteria which is required to reliably assess health risk.
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2
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Al-Qadiri HM, Al-Holy MA, Shiroodi SG, Ovissipour M, Govindan BN, Al-Alami N, Sablani SS, Rasco B. Effect of acidic electrolyzed water-induced bacterial inhibition and injury in live clam (Venerupis philippinarum) and mussel (Mytilus edulis). Int J Food Microbiol 2016; 231:48-53. [DOI: 10.1016/j.ijfoodmicro.2016.05.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 04/30/2016] [Accepted: 05/09/2016] [Indexed: 10/21/2022]
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3
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Ovissipour M, Al-Qadiri HM, Sablani SS, Govindan BN, Al-Alami N, Rasco B. Efficacy of acidic and alkaline electrolyzed water for inactivating Escherichia coli O104:H4, Listeria monocytogenes, Campylobacter jejuni, Aeromonas hydrophila, and Vibrio parahaemolyticus in cell suspensions. Food Control 2015. [DOI: 10.1016/j.foodcont.2015.01.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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4
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Matyar F, Akkan T, Uçak Y, Eraslan B. Aeromonas and Pseudomonas: antibiotic and heavy metal resistance species from Iskenderun Bay, Turkey (northeast Mediterranean Sea). ENVIRONMENTAL MONITORING AND ASSESSMENT 2010; 167:309-320. [PMID: 19551480 DOI: 10.1007/s10661-009-1051-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Accepted: 06/11/2009] [Indexed: 05/28/2023]
Abstract
We studied the susceptibility patterns to 15 different antibiotics and six heavy metals in Aeromonas spp. and Pseudomonas spp. isolated from Iskenderun Bay, Turkey (northeast Mediterranean Sea). A high percentage of Aeromonas isolates showed resistance to cefazolin (66.6%) and trimethoprim-sulphamethoxazole (66.6%). Amongst the Pseudomonas isolates, there was a high incidence of resistance to nitrofurantoin (86.2%), cefazolin (84.8%) and cefuroxime (71.7%). Most isolates showed tolerance to different concentrations of heavy metals, and minimal inhibition concentrations ranged from 25 to >3,200 microg/ml. The Aeromonas spp. and Pseudomonas spp. showed high resistance to copper of 98.3% and 75.4%, respectively, and low resistance to lead of 1.7% and 7.2%, respectively. Our results show that antibiotic and heavy metal resistant Aeromonas spp. and Pseudomonas spp. were widespread in Iskenderun Bay in 2007 and 2008. The increasing presence of antibiotic and heavy metal resistant Aeromonas spp. and Pseudomonas spp. may become a potential human health hazard.
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Affiliation(s)
- Fatih Matyar
- Department of Science and Technology Education, Faculty of Education, Cukurova University, 01330, Balcali, Adana, Turkey.
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5
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Edberg SC, Gallo P, Kontnick C. Analysis of the Virulence Characteristics of Bacteria Isolated from Bottled, Water Cooler, and Tap Water. MICROBIAL ECOLOGY IN HEALTH AND DISEASE 2009. [DOI: 10.3109/08910609609166445] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- S. C. Edberg
- Department of Laboratory Medicine and Internal Medicine, Yale University School of Medicine, New Haven, CTUSA
- Clinical Microbiology Laboratory, Yale New Haven Hospital, New Haven, CTUSA
| | - P. Gallo
- Clinical Microbiology Laboratory, Yale New Haven Hospital, New Haven, CTUSA
| | - C. Kontnick
- Clinical Microbiology Laboratory, Yale New Haven Hospital, New Haven, CTUSA
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Pap K, Tornai-Lehoczki J, Syposs Z. Mold challenge study in bottled natural mineral waters and spring waters. Acta Microbiol Immunol Hung 2008; 55:145-55. [PMID: 18595319 DOI: 10.1556/amicr.55.2008.2.6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Microbiological challenge study was carried out to verify the microbial stability of bottled waters against four different mold species isolated from bottled water (Fusarium sp.; Cladosporium sp.; Penicillium chrysogenum and Aspergillus fumigatus) and to follow the growth of the molds in bottled water. Twelve types of bottled water with different mineralization and CO2 level in PET and glass packages were collected from 4 European countries. Three different inoculation levels of spore suspensions were used to contaminate bottled water samples. The surviving colony forming unit (CFU) numbers and visual growth were monitored during the investigation period (26 weeks). The results of surviving CFU showed that the fungal growth is mostly determined by the carbonation level and the type of the mold strain. Neither the inoculation level nor the mineral content had any significant effect on the survival of the different mold strains. Results showed decreased CFU numbers in carbonated waters, while slow decreasing, stagnation or even some growth in still waters. A. fumigatus was the most resistant test species. None of the other tested mold strains survived the first 12-week test period in carbonated water. Visual growth was not detected in carbonated water samples, in contrast to all of the non-carbonated samples.
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Affiliation(s)
- Kata Pap
- Department of Microbiology and Biotechnology, Faculty of Food Sciences, Corvinus University of Budapest, Somlíi ut 14-16, H-1118 Budapest, Hungary
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7
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Yu CP, Farrell SK, Robinson B, Chu KH. Development and application of real-time PCR assays for quantifying total and aerolysin gene-containing aeromonas in source, intermediate, and finished drinking water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:1191-1200. [PMID: 18351092 DOI: 10.1021/es071341g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Aeromonas spp., opportunistic pathogens, are listed as a microbiological contaminant on the Environmental Protection Agency's (EPA) Drinking Water Contaminant Candidate List. Culture-based methods for identification and quantification of Aeromonas in drinking water are time-consuming and often fail to differentiate pathogenic species from nonpathogenic ones. This study reports successful development and applications of two real-time PCR assays, based on 16S rRNA gene sequences and a virulence gene (aerolysin gene), for rapid and effective quantification of total and aerolysin gene-containing Aeromonas spp. The assays successfully quantified total and aerolysin gene-containing Aeromonas in source, intermediate, and finished water samples collected from seven water works and one pilot plant. The effectiveness of Aeromonas removal by different drinking water treatment processes was examined by comparing the results obtained from the EPA culture-based method and developed real-time PCR assays. Regardless of the methods, our results indicated that conventional water treatment combination (prechlorination/ coagulation/sedimentation/rapid sand filtration) and membrane filtration alone could effectively remove Aeromonas. Slow sand filtration alone might not be effective. The removal efficiencies by different disinfection treatments were not determined, due to the lack of detectable Aeromonas. No Aeromonas was detected in samples with turbidity below 0.06 NTU.
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Affiliation(s)
- Chang-Ping Yu
- Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA
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8
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Dickerman B, Metzger J, Lee WT. Molecular Identification of Aeromonas and Coliform Bacteria Isolated on m Endo Media from Lake Erie Waters. World J Microbiol Biotechnol 2006. [DOI: 10.1007/s11274-005-4022-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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Pianetti A, Falcioni T, Bruscolini F, Sabatini L, Sisti E, Papa S. Determination of the viability of Aeromonas hydrophila in different types of water by flow cytometry, and comparison with classical methods. Appl Environ Microbiol 2005; 71:7948-54. [PMID: 16332772 PMCID: PMC1317354 DOI: 10.1128/aem.71.12.7948-7954.2005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Accepted: 08/25/2005] [Indexed: 11/20/2022] Open
Abstract
The presence of Aeromonas spp. in water can represent a risk for human health. Therefore, it is important to know the physiological status of these bacteria and their survival in the environment. We studied the behavior of a strain of Aeromonas hydrophila in river water, spring water, brackish water, mineral water, and chlorinated drinking water, which had different physical and chemical characteristics. The bacterial content was evaluated by spectrophotometric and plate count techniques. Flow cytometric determination of viability was carried out using a dual-staining technique that enabled us to distinguish viable bacteria from damaged and membrane-compromised bacteria. The traditional methods showed that the bacterial content was variable and dependent on the type of water. The results obtained from the plate count analysis correlated with the absorbance data. In contrast, the flow cytometric analysis results did not correlate with the results obtained by traditional methods; in fact, this technique showed that there were viable cells even when the optical density was low or no longer detectable and there was no plate count value. According to our results, flow cytometry is a suitable method for assessing the viability of bacteria in water samples. Furthermore, it permits fast detection of bacteria that are in a viable but nonculturable state, which are not detectable by conventional methods.
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Affiliation(s)
- Anna Pianetti
- Toxicological, Hygienic and Environmental Science Institute, Via S. Chiara, 27, University "Carlo BO," 61029 Urbino, Italy.
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10
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Sautour M, Mary P, Chihib NE, Hornez JP. The effects of temperature, water activity and pH on the growth of Aeromonas hydrophila and on its subsequent survival in microcosm water. J Appl Microbiol 2003; 95:807-13. [PMID: 12969295 DOI: 10.1046/j.1365-2672.2003.02048.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS The influence of temperature, water activity and pH on the growth of Aeromonas hydrophila, and on its survival after transfer in nutrient-poor water were assessed. METHODS AND RESULTS Experiments were carried out according to a Box-Behnken matrix at 10-30 degrees C, 0.95-0.99 water activity (aw) and pH 5-9. The effect of each factor on the kinetic parameters of growth (i.e. the maximal specific growth rate, mumax, and the lag time, lambda) and on the decline of the bacteria in microcosm water (time to obtain a reduction of 5 log, T5 log) were studied by applying central composite design. CONCLUSIONS The major effect of temperature and water activity on the growth of A. hydrophila was highlighted, whereas the effect of pH in these experimental conditions was not significant. Models describing the effect of environmental parameters on the growth of A. hydrophila were proposed. The effect of the growth environment, and particularly the incubation temperature, have an influence on the survival ability of the bacteria in nutrient-poor water. SIGNIFICANCE AND IMPACT OF THE STUDY The Box-Behnken design was well suited to determine the influence of environmental factors on the growth of A. hydrophila and to investigate the effect of previous growth conditions on its survival in microcosm water.
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Affiliation(s)
- M Sautour
- Laboratoire de Microbiologie, Université des Sciences et Technologies de Lille, Bâtiment, Villeneuve d'Ascq Cedex, France.
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12
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Villari P, Crispino M, Montuori P, Boccia S. Molecular typing of Aeromonas isolates in natural mineral waters. Appl Environ Microbiol 2003; 69:697-701. [PMID: 12514065 PMCID: PMC152379 DOI: 10.1128/aem.69.1.697-701.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A total of 103 isolates of Aeromonas spp. were obtained over a 3-year period from a natural mineral water and from surface streams located within the boundaries of the watershed of the natural mineral water wells and were typed by macrorestriction analysis of genomic DNA with XbaI and by pulsed-field gel electrophoresis. All Aeromonas caviae isolates from the natural mineral water belonged to the same clone, and an analogous clonal identity was found among Aeromonas hydrophila isolates. These two clones expressed no hemolytic or cytotoxic activities. Aeromonas isolates from surface waters showed high molecular heterogeneity and were not related to the clones found in the natural mineral water. The presence of aeromonads chronically found in the natural mineral water was a likely consequence of a localized development of a biofilm, with no exogenous contamination of the aquifer. Molecular fingerprinting of drinking water isolates is a useful tool in explaining possible reasons for bacterial occurrences.
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Affiliation(s)
- P Villari
- Department of Experimental Medicine and Pathology, University La Sapienza, 00161 Rome, Italy.
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13
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Messi P, Guerrieri E, Bondi M. Survival of an Aeromonas hydrophila in an artificial mineral water microcosm. WATER RESEARCH 2002; 36:3410-3415. [PMID: 12188142 DOI: 10.1016/s0043-1354(02)00028-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The survival capacity of an Aeromonas hydrophila strain (named SB14) isolated from mineral water was investigated in an artificial mineral water microcosm. The bacterial count of this microorganism was compared with two strains of other species from aquatic environments (Pseudomonas fluorescens SSD and Pseudomonas putida SSC) and a bacterium indicative of faecal pollution (Escherichia coli ATCC 25922). Among the strains, all added to sterile Pyrex glass flasks (1 l) to yield a final bacterial count of about 5 x 10(6) CFU/ml, A. hydrophila SB14 showed a quite strong survival capacity (150 days), even though the Pseudomonas strains were better adapted to this habitat (more than 240 days). E. coli ATCC 25922 was the least well fitted to survive and was no longer detected after 70 days. When A. hydrophila SB14 was inoculated together with one or two of the above strains, its survival appeared to be dependent on interaction with other organisms. A marked decrease in survival by 30 days, possibly due to antagonistic interaction, was observed when this microorganism was associated with E. coli ATCC 25922, and an increase by 30 and 60 days, possibly due to commensalic interaction, was obtained when A. hydrophila SB14 was inoculated with P. fluorescens SSD or P. putida SSC, respectively.
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Affiliation(s)
- P Messi
- Department of Biomedical Sciences, University of Modena and Reggio E, Modena, Italy.
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14
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Ramalho R, Cunha J, Teixeira P, Gibbs PA. Modified Pseudomonas agar: new differential medium for the detection/enumeration of Pseudomonas aeruginosa in mineral water. J Microbiol Methods 2002; 49:69-74. [PMID: 11777584 DOI: 10.1016/s0167-7012(01)00365-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pseudomonas aeruginosa has been implicated as a foodborne and waterborne pathogen and is now considered a primary infectious agent. In the present study, the survival of P. aeruginosa inoculated in mineral water was evaluated by drop counts on Pseudomonas Agar Base (PAB), PAB with CN supplement X107, PAB with cetrimide, PAB with nalidixic acid, and these media with added FeSO(4). Initial counts, before starvation, were the same in all media tested. Following this period, P. aeruginosa became sensitive to PAB with added cetrimide. The addition of FeSO(4) did not improve the recovery of stressed P. aeruginosa but gave colonies a typical dark brown colour being easily differentiated from other species that can grow at 42 degrees C. The modified Pseudomonas agar medium was also tested with several P. aeruginosa strains, other species of Pseudomonas, and other genera. Only P. aeruginosa strains (pyocyanin positive) produced the typical colonies. Our results demonstrate that Pseudomonas agar with ferrous sulphate, used for the differentiation of P. aeruginosa colonies, and nalidixic acid, used as an inhibitor of Gram-positive bacteria, might be a useful medium for the detection of injured P. aeruginosa in mineral water.
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Affiliation(s)
- Rita Ramalho
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua António Bernardino de Almeida, 4200-072, Porto, Portugal.
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15
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Croci L, Di Pasquale S, Cozzi L, Toti L. Behavior of aeromonas hydrophila in bottled mineral waters. J Food Prot 2001; 64:1836-40. [PMID: 11726170 DOI: 10.4315/0362-028x-64.11.1836] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The growth and survival of Aeromonas hydrophila in three types of natural mineral waters were investigated. Mineral waters with different levels of mineral content (low, medium, and high) were experimentally contaminated with A. hydrophila, stored at different temperatures (10 degrees C and 20 degrees C), and analyzed at intervals over a 60-day period. Water samples that were not experimentally contaminated were investigated for indigenous A. hydrophila. The results confirmed that A. hydrophila may occur naturally in mineral waters and showed that the level of mineral content, temperature, length of storage, and, in some cases, the type of container used may favor the growth of A. hydrophila. The greatest proliferation was observed in water with a low mineral content stored in PET bottles at 10 degrees C, in which A. hydrophila peaked at day 28 (4.47 +/- 0.01 log CFU/100 ml). At 20 degrees C, the same load was observed at day 60. The presence of high densities of A. hydrophila in bottled mineral water can constitute a risk for some groups of consumers, such as elderly and immunocompromised persons.
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Affiliation(s)
- L Croci
- Istituto Superiore di Sanità-Laboratorio Alimenti, Roma, Italy.
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16
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Mary P, Buchet G, Defives C, Hornez JP. Growth and survival of clinical vs. environmental species of Aeromonas in tap water. Int J Food Microbiol 2001; 69:191-8. [PMID: 11603856 DOI: 10.1016/s0168-1605(01)00491-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The ability of four species of Aeromonas (two of clinical and two of environmental origin) to survive and/or grow in tap water microcosms supplemented with sodium thiosulphate was tested. After bottling, the autochthonous microflora reached 6 x 10(5) cfu ml(-1) after a 5-day incubation period in tap water unfiltered and which was non-autoclaved. In filtered tap water, "ultramicrocells" were detected and final populations of ca. 10(6) cfu ml(-1) after 7 days were obtained. Aeromonas was inoculated at an initial cell concentration of ca. 10(4) cfu ml(-1). All strains were able to grow in tap water samples, which were filtered and autoclaved, and a final concentration of 10(5)-10(6) cfu ml(-1) was observed. Any inherent capability of Aeromonas to grow in tap water was eliminated by the presence of autochthonous microflora and "ultramicrocells" bacteria. Survival rates were strain- and microcosm-dependent. In unfiltered-non-autoclaved water, viable counts declined to below the detection limit (i.e. 1 log cfu ml(-1)) in 1.5 to 20 days. The declines in viable counts were even more pronounced in the filtered microcosm. Although inoculation ratios (100/1 in unfiltered-non-autoclaved and 1,000/1 in filtered microcosms) were favourable for aeromonads, at least for I to 3 days, the organisms disappeared in these microcosms. Thus, competition for nutrients was an unlikely cause of the limitation of aeromonads. The bacteriolytic effect of enzymes released by membrane vesicles from the autochthonous microflora and of "tail phage-like particles" bacteriocins were suggested as an in situ control of aeromonad populations. The present study showed that environmental strains of Aeromonas had no ecological advantage over clinical isolates. Thus, waterborne infections and contaminations of foods by pathogenic Aeromonas species could not be discounted.
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Affiliation(s)
- P Mary
- Laboratoire de Microbiologie, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
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17
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Ivanova EP, Zhukova NV, Gorshkova NM, Chaikina EL. Characterization of Aeromonas and Vibrio species isolated from a drinking water reservoir. J Appl Microbiol 2001; 90:919-27. [PMID: 11412322 DOI: 10.1046/j.1365-2672.2001.01318.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To study the phenotypic and chemotaxonomic (i.e. phospholipid and cellular fatty acid composition) characteristics of environmental Aeromonas spp. and Vibrio spp. isolated from a drinking water reservoir near Vladivostok City, and the application of some chemotaxonomic markers for discrimination of the two genera and species. METHODS AND RESULTS Presumptive Aeromonas species were dominant in surface water samples (up to 25% of the total number of bacteria recovered). These strains were consistent with respect to the cultural and biochemical properties used to define the species Aeromonas sobria (seven strains) and Aer. popoffii (three strains). Vibrio mimicus (two strains) and Vibrio metschnikovii (one strain) were identified according to phenotypic features and cellular fatty acid composition. CONCLUSION Environmental Aer. sobria isolates were atypical in their ability to grow at 42 degrees C, and were haemolytic, proteolytic and cytotoxic. Although it was present in a high proportion in the water samples, atypical Aer. sobria is not an indicator of polluted water. SIGNIFICANCE AND IMPACT OF THE STUDY The incidence of Aeromonas in the drinking water reservoirs in the Far East of Russia is reported for the first time.
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Affiliation(s)
- E P Ivanova
- Pacific Institute of Bio-organic Chemistry of the Far-Eastern Branch of the Russian Academy of Sciences, Vladivostok, Russia.
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18
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Yokomaku D, Yamaguchi N, Nasu M. Improved direct viable count procedure for quantitative estimation of bacterial viability in freshwater environments. Appl Environ Microbiol 2000; 66:5544-8. [PMID: 11097948 PMCID: PMC92502 DOI: 10.1128/aem.66.12.5544-5548.2000] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A direct viable count (DVC) procedure was developed which clearly and easily discriminates the viability of bacterial cells. In this quantitative DVC (qDVC) procedure, viable cells are selectively lysed by spheroplast formation caused by incubation with antibiotics and glycine. This glycine effect leads to swollen cells with a very loose cell wall. The viable cells then are lysed easily by a single freeze-thaw treatment. The number of viable cells was obtained by subtracting the number of remaining cells after the qDVC procedure from the total cell number before the qDVC incubation. This improved procedure should provide useful information about the metabolic potential of natural bacterial communities.
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Affiliation(s)
- D Yokomaku
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamada-oka, Suita, Osaka 565-0871, Japan
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19
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Warburton D. Methodology for screening bottled water for the presence of indicator and pathogenic bacteria. Food Microbiol 2000. [DOI: 10.1006/fmic.1999.0283] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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Villari P, Pucino A, Santagata N, Torre I. A comparison of different culture media for the membrane filter quantification of Aeromonas in water. Lett Appl Microbiol 1999; 29:253-7. [PMID: 10583754 DOI: 10.1046/j.1472-765x.1999.00632.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A comparative assessment of culture media for the membrane filter enumeration of Aeromonas spp. in water was performed, testing the effects of different incubation conditions (aerobic and anaerobic), temperatures (30 and 37 degrees C) and times (24 and 48 h). Different water samples seeded with test suspensions of Aeromonas spp., fecal material or raw sewage were examined. Results indicate clearly that plates should be incubated aerobically at 30 degrees C for 24 h. If the bacterial contamination is likely to be low, the use of most sensitive culture media, such as SAA, mA, ADA or PADE Agar, is recommended. By contrast, samples with an expected high level of background microbial flora should be analysed through more selective media, such as MIX Agar. However, the low selectivity of all media tested and the high likelihood of false negatives based upon the macroscopic examination of colonies means that further research directed to the development of more efficient media is needed.
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Affiliation(s)
- P Villari
- Department of Health and Preventive Sciences, University Federico II, Naples, Italy
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21
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Brandi G, Sisti M, Giardini F, Schiavano GF, Albano A. Survival ability of cytotoxic strains of motile Aeromonas spp. in different types of water. Lett Appl Microbiol 1999; 29:211-5. [PMID: 10583745 DOI: 10.1046/j.1365-2672.1999.00584.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ability of motile Aeromonas spp. to survive in drinking water (mineral and tap water) and in sea water was experimentally tested. Clinically isolated cytotoxic strains of A. hydrophila, A. caviae and A. sobria were selected for this study. After contamination of water samples, the survival of Aeromonas strains was studied for at least three months using viable counts. The results obtained show that the survival of the Aeromonas spp. varies considerably depending on species and water type. For all three species, the survival time was longest in mineral water, where viable bacteria of each strain were still detected after 100 d. Moreover, A hydrophila and A. caviae also re-grew on the first day. In tap water all strains showed marked survival, although to a lesser extent than in mineral water. Aeromonas cells showed a rapid decline in sea water (90% reduction in viable cells after about two d) and thus seem to be more sensitive to saline/marine stress than chlorination.
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Affiliation(s)
- G Brandi
- Istituto di Scienze Tossicologiche Igienistiche e Ambientali, Università di Urbino, Italy.
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22
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Fujikawa H, Aketagawa J, Nakazato M, Wauke T, Tamura H, Morozumi S, Itoh T. Growth of moulds inoculated into commercial mineral water. Lett Appl Microbiol 1999; 28:211-5. [PMID: 10196771 DOI: 10.1046/j.1365-2672.1999.00513.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The growth of mould spores of Penicillium sp. and Cladosporium sp. inoculated in a commercial mineral water product was studied. The strains had been isolated as fungal foreign bodies in commercial mineral waters. In product A, which was not originally sterilized and was contaminated with psychrophilic bacteria, the inoculated mould spores of the strains did not grow; no increases in viable colony counts or beta-glucans concentration in the samples were observed during storage. In a sterilized product A, inoculated spores of the strains grew into visible foreign bodies. The viable colony counts and the beta-glucans concentration in the samples increased during storage. These results showed that in a sterilized mineral water product, mould spores could grow into visible foreign bodies.
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Affiliation(s)
- H Fujikawa
- Department of Microbiology, Tokyo Metropolitan Research Laboratory of Public Health, Japan.
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Palumbo SA, Rajkowski KT, Miller AJ. Current approaches for reconditioning process water and its use in food manufacturing operations. Trends Food Sci Technol 1997. [DOI: 10.1016/s0924-2244(97)01014-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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24
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Huys G, Kämpfer P, Vancanneyt M, Coopman R, Janssen P, Kersters K. Effect of the growth medium on the cellular fatty acid composition of aeromonads: consequences for the chemotaxonomic differentiation of DNA hybridization groups in the genus Aeromonas. J Microbiol Methods 1997. [DOI: 10.1016/s0167-7012(96)00969-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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25
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Abstract
Pseudomonas aeruginosa is an ubiquitous environmental bacterium. It can be recovered, often in high numbers, in common food, especially vegetables. Moreover, it can be recovered in low numbers in drinking water. A small percentage of clones of P. aeruginosa possesses the required number of virulence factors to cause infection. However, P. aeruginosa will not proliferate on normal tissue but requires previously organs. Further narrowing the risk to human health is that only certain specific hosts are at risk, including patients with profound neutropenia, cystic fibrosis, severe burns, and those subject to foreign device installation. Other than these very well-defined groups, the general population is refractory to infection with P. aeruginosa. Because of its ubiquitous nature, it is not only not practical to eliminate P. aeruginosa from our food and drinking water, but attempts to do so would produce disinfection byproducts more hazardous than the species itself. Moreover, because there is no readily available sensitive and specific means to detect and identify P. aeruginosa available in the field, any potential regulation governing its control would not have a defined laboratory test measure of outcome. Accordingly, attempts to regulate P. aeruginosa in drinking water would not yield public health protection benefits and could, in fact, be counterproductive in this regard.
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Affiliation(s)
- C Hardalo
- Clinical Microbiology Laboratory, Yale-New Haven Hospital, CT, USA
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26
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Edberg SC, LeClerc H, Robertson J. Natural protection of spring and well drinking water against surface microbial contamination. II. Indicators and monitoring parameters for parasites. Crit Rev Microbiol 1997; 23:179-206. [PMID: 9226113 DOI: 10.3109/10408419709115135] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Recent outbreaks of cryptosporidiosis and reports of other newly described para-sitic diseases associated with drinking water transmission prompted a reevaluation of source water monitoring criteria for public health protection. The field of microbial indicators was reviewed and each candidate sentinel evaluated in terms of its sensitivity, specificity, and technical feasibility. In addition, a clear distinction was made between source water monitoring and monitoring in the distribution system. Of all potential candidate microbial sentinels, Escherichia coli is deemed the most efficacious for public health protection. Based on a conservative estimate of its half-life in groundwater for 8 d, it is recommended that at least two samples be obtained during this half-life. In addition to E. coli, two water quality indicator sentinels, which are not necessarily direct public health threats, should also be monitored at the same frequency. These are the total coliform group and the enterococci. If E. coli is present in any source water sample, the borehole and any directly connected borehole should be embargoed. If either total coliforms or enterococci are detected, only that individual borehole should be taken off line and not used until the situation is remediated and the cause of the fecal contamination eliminated. Clostridium perfringens spores serve as a useful long-lived indicator. However, their perseverance in a sample should not be considered a direct public health threat because spores may far outlive pathogens. As a parasite indicator, C. perfringens should have the same importance as a positive coliform or enterococcus analysis. Coliphages do not yet fulfill enough of the criteria to be routinely employed. Biological monitoring should be coupled with physicochemical monitoring to establish a long-term history of the source. Because all natural waters vary in the amounts of heterotrophic plate count bacteria, test methods should be employed that are refractory to them. A combination of rigorous source protection plus extraordinary source monitoring serve as sufficient multiple barriers for parasite protection.
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Affiliation(s)
- S C Edberg
- Laboratory Medicine and Internal Medicine, Yale University School of Medicine, New Haven, CT 06520-8035, USA
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27
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Warburton DW, Bowen B, Konkle A, Crawford C, Durzi S, Foster R, Fox C, Gour L, Krohn G, LaCasse P. A comparison of six different plating media used in the isolation of Salmonella. Int J Food Microbiol 1994; 22:277-89. [PMID: 7986679 DOI: 10.1016/0168-1605(94)90179-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Seventeen Canadian Federal, Provincial and Public Health Laboratories took part in different phases of a comparative/collaborative study that evaluated rapid methods to the standard Health Protection Branch (HPB) method for the detection of Salmonella. A variety of commercial media were tested, including Brilliant Green Sulpha Agar, Bismuth Sulphite Agar, Hektoen Enteric Agar, Xylose Lysine Deoxycholate Agar, EF-18 Agar and Rambach Agar. Each laboratory compared up to six of these different plating media. Plating of 123 salmonellae cultures and 28 artificially-inoculated foods showed the recovery of Salmonella spp. on the six plating media to be within one log. Therefore, quantitative testing of the media showed them to be comparable in the recovery of salmonellae. Qualitative testing of the six media during the comparative/collaborative study of various methods showed that EF-18 Agar recovered the greatest number of isolates. Hektoen Enteric Agar ranked second, with the other agars being comparable in their recovery of Salmonella spp. Problems with the various media are summarized. Based on our results and those of other researchers, it is recommended that Bismuth Sulphite Agar be compulsory and that at least one other agar be used for newly developed cultural procedures.
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Affiliation(s)
- D W Warburton
- Evaluation Division, Bureau of Microbial Hazards, HPB Health and Welfare Canada, Ottawa
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