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Öğe Alkaline protease production by an actinomycete MA1-1 isolated from marine sediments(Springer, 2007) Hames-Kocabas, E. Esin; Uzel, AtacAlkaliphilic actinomycetes isolated from sediment samples of the Izmir Gulf, Turkey were studied for the production of protease activity. Strain MA1-1 was selected as a good alkaline protease producer as measured by the clear zone diameter by the hydrolysis of skim-milk and casein. The alkaline protease production from the marine alkaliphilic actinomycete MA1-1 was studied by using different carbon and nitrogen sources in medium containing glycerol, peptone, KCl, MgSO4, K2HPO4, and trace elements at 30 degrees C for 72 h. Among the different carbon and nitrogen sources, fructose, starch, maltose, D(+) glucose, yeast extract, malt extract, beef extract and peptone provided higher production of protease. Starch was also found to be effective for growth and enzyme production with highest specific activity at 699 U mg(-1). Purification was achieved by adsorption on Diaion HP 20 which resulted in a recovery rate of 68% with a specific activity of 7618 U mg(-1) protein and 40-fold purification. The optimum pH and temperature of the partially purified protease were determined as pH 9.0 and 50 degrees C, but high activity was also observed at pH 8.0-13.0 and 35-50 degrees C. The inhibition profile exhibited by phenylmethylsulphonyl fluoride (PMSF) showed that this enzyme belongs to the serine-protease group.Öğe Anti-Microbial Activity of Chloramphenicol from Streptomyces sp.10CM9(Elsevier Science Bv, 2015) Ozcan, Kadriye; Uzel, Atac; Bedir, Erdal; Sener, S; Saridogan, E; Staub, SAn antimicrobial agent, chloramphenicol, was isolated from Actinobacteria 10CM9. The strain was isolated from lake sediment collected from Ercek Lake, Van (38 degrees 29'57.76 '' N and 43 degrees 33'10.98 '' E) and AIA medium was used as a isolation medium. 16S rRNA gene sequence analysis that showed the strain belongs to the genus Streptomycetes. A fermentation study in AIA broth medium (3L) followed by extraction with EtOAc afforded 105mg of crude extract. A bioactivity-guided fractionation by Open Column chromatography on silica gel led to the isolation of one secondary metabolite (10CM19-01, 31 mg). Structures of the metabolites were established as chloramphenicol, by means of NMR (H-1, C-13 and COSY) data. Antimicrobial activity of 10CM9 was tested by microdilution method against enteropathogenic Escherichia coli 0157:H7 (RSKK 234), methicillin resistant Staphylococcus aureus ATCC 43300, vancomycin resistant Enterococcus faecium DSMZ 13590, Candida albicansDSMZ 5817 and Pseudomonas aeruginosa ATCC 27853. As a result, 0.5 mu g/ml, 0.5 mu g/ml and 1 mu g/ml MIC values were observed against Escherichia coli 0157:H7, Enterococcus faecium and Staphylococcus aureus, respectively. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.Öğe Benzodiazepine Derivatives from Marine-Derived Streptomyces cacaoi 14CM034(Acg Publications, 2021) Aksoy, Semiha Cetinel; Kucuksolak, Melis; Uzel, Atac; Bedir, Erdal7-methoxy-8-hydroxy cycloanthranilylproline (2), a new natural product with pyrrolobenzodiazepine (PBD) framework, was isolated from marine-derived actinobacterium Streptomyces cacaoi 14CM034, together with cycloanthranilylproline (1). Structural elucidation of the compounds was based on FTIR, 1D-(H-1 and C-13 NMR), 2D-NMR (COSY, HMBC and NOESY) and HR-MS analyses. Compounds 1 and 2 exhibited notable antimicrobial activity. The presence of PBD derivatives in S. cacaoi was first demonstrated with this study.Öğe Bioactive Sheath/Core Nanofibers Containing Olive Leaf Extract(Wiley-Blackwell, 2016) Dogan, Gamze; Basal, Guldemet; Bayraktar, Oguz; Ozyildiz, Figen; Uzel, Atac; Erdogan, IpekThis study aimed at producing silk fibroin (SF)/hyaluronic acid (HA) and olive leaf extract (OLE) nanofibers with sheath/core morphology by coaxial electrospinning method, determining their antimicrobial properties, and examining release profiles of OLE from these coaxial nanofibers. Optimum electrospinning process and solution parameters were determined to obtain uniform and bead-free coaxial nanofibers. Scanning electron microscopy and transmission electron microscopy (TEM) were used to characterize the morphology of the nanofibers. The antimicrobial activities of nanofibers were tested according to AATCC test method 100. Total phenolic content and total antioxidant activity were tested using in vitro batch release system. The quality and quantity of released components of OLE were determined by high-performance liquid chromatography. The changes in nanofibers were examined by Fourier-transform infrared spectroscopy. Uniform and bead-free nanofibers were produced successfully. TEM images confirmed the coaxial structure. OLE-loaded nanofibers demonstrated almost perfect antibacterial activities against both of gram-negative and gram-positive bacteria. Antifungal activity against C. albicans was rather poor. After a release period of 1 month, it was observed that similar to 70-95% of the OLE was released from nanofibers and it was still bioactive. Overall results indicate that the resultant shell/core nanofibers have a great potential to be used as biomaterials. (C) 2015 Wiley Periodicals, Inc.Öğe Biodiversity and bioactivity of some marine sediment derived actinomycetes from Turkey(Elsevier Science Bv, 2012) Ozcan, Kadriye; Aksoy, Semiha Cetinel; Kalkan, Orcun; Uzel, Atac; Hames-Kocabas, E. Esin; Yokes, M. Baki; Bedir, ErdalÖğe Bioprospecting of hot springs and compost in West Anatolia regarding phytase producing thermophilic fungi(Verlag Ferdinand Berger Sohne Gesellschaft Mbh, 2020) Ozdemir, Sennur Caliskan; Uzel, AtacPhytase is commonly used as feed supplement for poultry and catalyses the hydrolysis of phytate into inorganic phosphates and myo-inositol phosphates. Extreme environments, especially warm habitats constitute an important resource for the discovery of microorganisms with unique enzymes. Therefore, we aimed to investigate the culturable thermophilic and thermotolerant fungal biodiversity of hot springs and compost samples in Western Anatolia and their extracellular phytase production capacities for the first time. A total of 43 environmental samples (26 soils and 17 sediments) were collected from 17 different hot springs and 1 compost sample was taken from a mushroom farm. A total of 48 filamentous fungal strains were isolated. Fourteen (29 %) strains were classified as thermophilic and 34 (71 %) strains as thermotolerant regarding to their heat requirements. Of the 48 isolates, 33 (69 %) were Aspergillus species. All isolates were quantitatively screened for their extracellular phytase activities and 42 (88 %) of the 48 isolates produces phytase in a range of 8.82 - 331.22 (U/mg). This study demonstrates that hot springs in West Anatolia harbour a rich thermophilic/thermotolerant fungal diversity possessing phytase producing potential and mushroom farming selectively enhances thermophilic fungi.Öğe Biotransformation of betulin to betulinic acid by Fusarium lacertarum BRF59, an endophytic fungus isolated from the genus Betula(Elsevier, 2024) Gokfiliz-Yildiz, Pelin; Caliskan, Sennur; Yildirim, Hasan; Uzel, AtacBetulinic acid (BA), a betulin derivative, is an important plant-based natural product. BA has many biological activities and attracts attention especially as a promising antitumour drug. Extraction from plants or semisynthesis from betulin are the common methods to obtain BA, but these methods have some drawbacks. In recent years, microbial biotransformation of betulin to BA has been anticipated as an alternative method. Betulin is abundant in the outer bark of birch (Betula spp.) and obtained from these plants, however endophytes of Betula spp. have not been investigated for biotransformation of betulin to BA before. Therefore, this study aimed to investigate the culturable endophytes of Betula pubescens var. litwinowii (Doluch.) Ashburner & McAll and to determine their biotransformation capacity of betulin to BA. To this end, bacterial and fungal endophytes were isolated from the surface-sterilized root, stem, and branch samples. A total of 37 endophytes (11 bacteria and 26 fungi) were identified by polyphasic approach. All endophytes were screened for the biotransformation of betulin to BA. Betulin and BA content of the extracts were determined by RP-HPLC analysis. Two different bacterial and fungal biotransformation processes were designed. It was found that the fungus BRF59 produced BA via betulin biotransformation under the Fungal Biotransformation Process-2 when the fungus was acclimatized to betulin before biotransformation, and glycerol was used as a carbon source, instead of glucose, during bioprocess. The highest BA yield and BA concentration was obtained as 12.22 +/- 0.94 % and 80.85 +/- 2.64 mg/ml, respectively, under non-optimized conditions. The fungal isolate BRF59, belonging to the genus Fusarium according to ITS analysis, was further identified based on RPB2 sequence analysis and found that Fusarium lacertarum. In conclusion, this study demonstrated that betulin was biotransformed to BA by an endophytic fungus isolated from the genus Betula for the first time. F. lacertarum BRF59 might be a good candidate for production of BA through betulin biotransformation and, using glycerol as a carbon source during biotransformation might enable this by-product to convert value-added chemical. (c) 2024 SAAB. Published by Elsevier B.V. All rights reserved.Öğe Characterisation of a thermostable and proteolysis resistant phytase fromPenicillium polonicumMF82 associated with the marine spongePhorbassp.(Taylor & Francis Ltd, 2020) Kalkan, Saban Orcun; Bozcal, Elif; Tuna, Elif Esin Hames; Uzel, AtacPhytases are widely used in human and animal nutrition, aquaculture, soil amendment, and in the production of lower myo-inositol phosphates for clinical purposes. Some of these applications, especially feed industry require robust enzymes. Since the marine environments are less studied compared to terrestrial environments, we evaluated the extracellular phytase activity of 110 marine derived filamentous fungal (MDFF) strains previously isolated from sponge and sediment samples of the Turkey. MDFF strains were qualitatively screened for their extracellular phytase activities andP. polonicumMF82 phytase was further characterized following partial purification. Optimum pH and temperature were determined as 5.5 and 60 degrees C respectively. A significant relative phytase activity was observed in the presence of urea and acetone. However, there was no phytase activity followed by the treatment with Triton X-100 and Tween 80. Characterization studies revealed thatP. polonicumMF82 phytase has superior properties for industrial use including wide pH and temperature range for activity, high optimum activity temperature, high thermal and pH stability, resistance to many enzyme inhibitors including various heavy metals, denaturants, detergents, proteases and organic solvents. Phytase extracellularly produced byP. polonicumMF82 strain presents a good candidate for commercial applications. This study demonstrates that the MDFF strains are prolific sources for phytase and presents the first report about the production and characterization of the phytase from a marine-derivedP. polonicumstrain.Öğe Colonization and vertical transmission of Streptococcus mutans in Turkish children(Elsevier Gmbh, Urban & Fischer Verlag, 2008) Hames-Kocabas, E. Esin; Ucar, Fuesun; Ersin, Nazan Kocatas; Uzel, Atac; Alpoz, Ali RizaThe aim of the study was to establish the colonization of Streptococcus mutons and to determine the possibility of intra-familial transmission in a group of Turkish children and their parents. A total of 56 children participated in the study together with their parents (20 fathers and 49 mothers). Saliva samples were collected from the individuals and cultivated on S. mutans selective TYCSB agar. The typical isolates of S. mutans were identified by using classical. microbiological methods, as well as molecular typing of S. mutans clones. which was performed by using AP PCR with OPA5 primer for the detection of transmission. The vertical transmission of salivary S. mutans was detected among 14 mother-father-child, 35 mother-child (one twins) and 6 father-child combinations. The homologies of strain types were recorded as 24% and 16.6% for mother-child and father-child combinations, respectively. A significant positive correlation (p<0.001) was found between the infected children and their parents with high S. mutans counts. (C) 2006 Elsevier GmbH. All rights reserved.Öğe The correlation between serum immunoglobulin A and immunoglobulin G levels and the presence of Treponema denticola in human periapical lesions(Elsevier Science Inc, 2007) Cogulu, Dilsah; Oncag, Ozant; Kutukculer, Necil; Uzel, Atac; Eronat, CemalThe aim of this study was to compare the serum immunoglobulin A (IgA) and immunoglobulin G (IgG) levels and the presence of Treponema denticola in the root canals in a group of teeth with/without periapical lesion. A total of 66 children aged 8 to 13 years old were involved in this study. Five milliliters of blood samples were taken to detect the serum IgA and IgG levels. Sixty-six endodontic samplings were also obtained to determine the presence of T. denticola by polymerase chain reaction. The presence of T. denticola between the groups with/without periapical lesion was statistically significant (p = 0.026). A significant negative correlation was found between serum IgG and IgA levels and the presence of T. denticola (p = 0.023 and 0.038, respectively). This study may support the hypothesis that the presence of T. denticola in the root canals is mainly related to the periapical lesions, and the higher levels of serum IgG and IgA levels may protect against T. denticola.Öğe Cultivable sponge-associated actinobacteria: Phylogenetic diversity and antimicrobial activities(Elsevier Science Bv, 2012) Oner, Ozlem; Ekiz, Guner; Hames-Kocabas, E. Esin; Demir, Volkan; Gube, Ozkan; Ozkaya, F. Can; Yokes, M. Baki; Uzel, Atac; Bedir, ErdalÖğe Cytosine-type nucleosides from marine-derived Streptomyces rochei 06CM016(Japan Antibiotics Research Assoc, 2016) Aksoy, Semiha Cetinel; Uzel, Atac; Bedir, ErdalRocheicoside A (3), a nucleoside analog possessing a novel 5-(hydroxymethyl)-5-methylimidazolidin-4-one substructure, was isolated from marine-derived actinomycete Streptomyces rochei 06CM016, together with a new (4) and three known compounds. Structures of the new metabolites were elucidated by one-dimensional (H-1 and C-13) and 2D NMR (COSY, HMQC and HMBC) and HR-TOF-MS analyses. All the metabolites exhibited significant antimicrobial activity. A plausible mechanism was proposed for compound 3's formation from amicetin.Öğe Diversity and antibiotic-producing potential of cultivable marine-derived actinomycetes from coastal sediments of Turkey(Springer Heidelberg, 2013) Ozcan, Kadriye; Aksoy, Semiha Cetinel; Kalkan, Orcun; Uzel, Atac; Hames-Kocabas, E. Esin; Bedir, ErdalMarine environments, especially sediments, are rich sources of actinomycetes that provide many bioactive compounds, primarily antibiotics. The goal of this study was to investigate the diversity of cultivable actinomycetes and their potential to produce antibiotics from sediments collected from the coastal zones of Turkey. Thirty sediment samples were collected from nine different coastal sites in three seas surrounding the Anatolian Peninsula of Turkey. Of the samples, 6 were collected from one site in the Black Sea, 18 from seven sites in the Aegean Sea, and 6 from one site in the Mediterranean Sea. Strains of pure actinomycetes were isolated by modified actinomycetes isolation agar (MAIA), M1 agar, M6 agar, and modified R2A agar. Ethyl acetate extracts and fermentation broths were used for the evaluation of antimicrobial activity against antibiotic resistant test microorganisms. The identification of the isolates was undertaken by 16S rRNA gene sequencing. A total of 261 strains of actinomycetes were isolated, of which 66 (25 %) were active against at least one antibiotic-resistant microorganism. Sixty-five of the actinomycetes isolates with antimicrobial activity were Streptomyces spp. and one was Nocardia sp., which implied that genus Streptomyces was predominant. Whereas MAIA agar was the best medium to recover actinomycetes, M6 agar was superior to others for the isolation of antibiotic-producing strains. Extensive screening of the extracts from the 261 isolates for antimicrobial activities revealed considerable potential to produce antibiotics. These findings imply that actinomycetes from marine sediments of the Anatolian Peninsula coasts have potential for the discovery of novel bioactive compounds.Öğe Evaluation of the Etiological Factors of Black Tooth Stain in Children(Galenos Publ House, 2023) Ilgen, Gulsen; Cogulu, Dilsah; Ucan, Ege; Uzel, AtacAim: Tooth discoloration is a common clinical finding which is considered primarily as an aesthetic problem. Black stain (BS) is a specific type of extrinsic tooth discoloration mostly seen in children, but also in adults and it is not dependent on gender. The present study aimed to investigate the relationships between the presence of BS and dental caries incidence, dental plaque scores and to examine the colonization of Streptococcus mutans, Lactobacillus spp., Actinomyces spp. and Capnocytophaga spp. in dental plaque samples with or without BS. The socioeconomic status of the family, the oral hygiene and dietary habits of the children, and the medical and dental history of the children were also compared between the two groups.Materials and Methods: A total of 1000 children aged 3-12 years were evaluated to take part in this study. From this group, those children with BS (n=44) were selected as the study group. With the same number as the study group, and with a same age and gender profile, 44 children without BS were selected as a control group. Dental examinations including the presence of BS, dental caries incidence and dental plaque scores were performed by the same investigator. Structured questionnaires were completed by the parents. The levels of S. mutans, Lactobacillus spp., Actinomyces spp. and Capnocytophaga spp. were determined from dental plaque samples. All data were analyzed by SPPS 25.0 using Student's t-test, the Mann-Whitney U, Fisher's exact and the chi-squared tests. Results: BS was detected in 4.4% of the patients in the present study. DMFT and DMFS scores were significantly lower in those children with BS than in those without BS (p=0.001 and p=0.010). However, no statistically significant difference was found between dmft and dmfs scores and the presence of BS (p>0.05). Lower numbers of S. mutans and Lactobacillus spp. and greater numbers of Actinomyces spp. and Capnocytophaga spp. were found in those children with BS. There was no statistically significant relationship between S. mutans and Actinomyces spp. and the presence of BS (p>0.05). Colonizations of Lactobacillus spp. were statistically significantly lower, while colonizations of Capnocytophaga spp. were significantly higher in the BS group than in the control group (p<0.05).Conclusion: It could be suggested that the different microbial composition of BS might be associated with lower caries experiences in affected subjects.Öğe Investigation of enteropathogenic Escherichia coli and Shiga toxin-producing Escherichia coli associated with hemolytic uremic syndrome in Izmir Province, Turkey(Tubitak Scientific & Technical Research Council Turkey, 2016) Bozcal, Elif; Yigitturk, Gurkan; Uzel, Atac; Aydemir, Sabire SohretBackground/aim: The purpose of this study was to investigate Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic Escherichia coli (EPEC) strains originating from diarrheagenic patients. Materials and methods: A total of 102 patients with diarrhea between October 2012 and January 2013 were enrolled in this study. Multiplex and standard polymerase chain reactions were performed to detect and distinguish STEC and EPEC strains. O serotyping of EPEC was carried out by monovalent antisera. The O and H serotyping of STEC strains was performed at the Refik Saydam Institute, Ankara. Results: A total of 5 (3.42%) strains were identified as STEC, and 3 strains (2.05%) were atypical EPEC. One of the STEC serotypes was O157:H7 carrying VT1, Stx1A, and escv genes. The other STEC strain was identified as O174:H21, which is associated with hemolytic uremic syndrome and consists of VT2 and Stx2A genes. One of the EPEC and three of the STEC serotypes were nontypeable. The serotypes of the atypical EPEC strains were identified as O114 and O26. Conclusion: To the best of our knowledge, this is the first report of O174:H21 from the Izmir region that was shown to be a Shiga toxin-producing non-O157 serotype of STEC.Öğe Isolation of secondary metabolites from a marine derived Streptomyces sp 9CM17 and investigation of their antimicrobial activities(Elsevier Science Bv, 2012) Ozcan, Kadriye; Uzel, Atac; Hames-Kocabas, E. Esin; Bedir, ErdalÖğe Isolation strategies of marine-derived actinomycetes from sponge and sediment samples(Elsevier Science Bv, 2012) Hames-Kocabas, E. Esin; Uzel, AtacDuring the last two decades, discoveries of new members of actinomycetes and novel metabolites from marine environments have drawn attention to such environments, such as sediment and sponge. For the successful isolation of actinomycetes from marine environments, many factors including the use of enrichment and pre-treatment techniques, and the selection of growth media and antibiotic supplements should be taken into account. High-throughput cultivation is an innovative technique that mimics nature, eliminates undesired, fast-growing bacteria and creates suitable conditions for rare, slow-growing actinomycetes. This review comprehensively evaluates the traditional and innovative techniques and strategies used for the isolation of actinomycetes from marine sponge and sediment samples. (C) 2012 Elsevier B.V. All rights reserved.Öğe Juniperus macrocarpa endophytes isolated on standard- and plant extract supplemented-culture media- and evaluation of their antimicrobial activity(Univ Belgrade, Inst Botany & Botanical Garden, 2022) Caliskan, Sennur; Gokfiliz-Yildiz, Pelin; Ozmen, Aysegul; Yildirim, Hasan; Uzel, AtacThis study aimed to investigate the endophytes of Juniperus macrocarpa collected from gesme in Izmir, Turkey, using a culture-dependent approach and to evaluate their antimicrobial activity for the first time. Since endophytes interact with phy-tochemicals of the host plant, in addition to the standard culture media, a J. mac-rocarpa extract supplemented culture media was also used for isolation to enhance the cultivability of the endophytes. Six bacteria out of twelve and three fungi out of seven were isolated from the plant extract supplemented culture media. The gen-otypic identification of the bacterial and fungal isolates was determined based on 16S rDNA and Internal Transcribed Spacer (ITS) sequence analysis, respectively. The genus Juniperus, which has ethnopharmacological uses, is rich in phytochem-icals with multiple bioactivities. Since Juniperus spp. is listed as a priority natural habitat, it is necessary to find alternative resources that could replace the bioactive compounds of these plants. Endophytes of Juniperus spp. might be good candidates as antimicrobial producers. From this point of view, the antimicrobial activity of the crude fermentation liquid of the J. macrocarpa endophytes, and also aqueous and methanolic extracts of J. macrocarpa, were evaluated using a disc diffusion assay against a panel of test microorganisms, including antibiotic resistant ones. One fungus and seven bacteria showed remarkable antimicrobial activity against at least one test microorganism. These results indicated that some endophytes of J. macrocarpa had antimicrobial properties like their host plant and could substitute these plants as a source of antimicrobials.Öğe LEGIONELLA PNEUMOPHILA: LEGIONNARIES' DISEASE(Nova Science Publishers, Inc, 2010) Uzel, Atac; Hames-Kocabas, E. Esin; Lutsenko, A; Palahniuk, VLegionella pneumophila was recognized as an important human pathogen after the first discovery during an investigation of a pneumonia outbreak among American Legion convention in 1976 in Philadelphia, USA. L. pneumophila is a gram-negative, mesophilic, facultative intracellular parasitic and nonspore-forming rod-shaped bacterium belonging to the gamma-subgroup of proteobacteria. L. pneumophila inhabits natural freshwater environments at low concentration. Along with the transfer from natural aquatic habitats into man-made water systems such as cooling towers, evaporative condensers, water distribution systems, whirlpool spas and hot water tanks, L. pneumophila reaches high cell density and can cause Legionnaires' disease (pneumonic legionellosis) or Pontiac fever (severe influenza-like illness). Infection occurs primarily via the inhalation of L. pneumophila-contaminated aerosols. In aquatic habitats, L. pneumophila cells are intracellular parasites of freshwater protozoa and use a similar mechanism to multiply within mammalian cells. L. pneumophila can also multiply extracellularly within biofilms and can persist within these microbial communities for years. Transmission to human primarily occurs via the inhalation of L. pneumophila containing aerosols. The bacterium enters to human phagocytic cells by coiling or conventional phagocytosis then inhibits phagosome-lysosome fusion and multiplies in the phagosome. A number of virulence factors have been described for L. pneumophila such as surface proteins, secreted factors and putative virulence factors. L. pneumophila can be identified by using cultural, serologic and various molecular techniques such as DNA sequencing and DNA-DNA hybridization. Diagnosis can be made by culture, direct fluorescent antibody staining, serological tests, urinary antigen detection or nucleic acid detection and various subtyping techniques. In order to eradicate L. pneumophila from contaminated water systems several methods are available; Thermal or chemical shock \disinfection, UV irradiation, ozone treatment, silver-copper ionization, anodic oxidation and chlorine dioxide application.Öğe LEGIONELLA PNEUMOPHILA: LEGIONNARIES' DISEASE(Nova Science Publishers, Inc, 2010) Uzel, Atac; Hames-Kocabas, E. Esin; Lutsenko, A; Palahniuk, VLegionella pneumophila was recognized as an important human pathogen after the first discovery during an investigation of a pneumonia outbreak among American Legion convention in 1976 in Philadelphia, USA. L. pneumophila is a gram-negative, mesophilic, facultative intracellular parasitic and nonspore-forming rod-shaped bacterium belonging to the gamma-subgroup of proteobacteria. L. pneumophila inhabits natural freshwater environments at low concentration. Along with the transfer from natural aquatic habitats into man-made water systems such as cooling towers, evaporative condensers, water distribution systems, whirlpool spas and hot water tanks, L. pneumophila reaches high cell density and can cause Legionnaires' disease (pneumonic legionellosis) or Pontiac fever (severe influenza-like illness). Infection occurs primarily via the inhalation of L. pneumophila-contaminated aerosols. In aquatic habitats, L. pneumophila cells are intracellular parasites of freshwater protozoa and use a similar mechanism to multiply within mammalian cells. L. pneumophila can also multiply extracellularly within biofilms and can persist within these microbial communities for years. Transmission to human primarily occurs via the inhalation of L. pneumophila containing aerosols. The bacterium enters to human phagocytic cells by coiling or conventional phagocytosis then inhibits phagosome-lysosome fusion and multiplies in the phagosome. A number of virulence factors have been described for L. pneumophila such as surface proteins, secreted factors and putative virulence factors. L. pneumophila can be identified by using cultural, serologic and various molecular techniques such as DNA sequencing and DNA-DNA hybridization. Diagnosis can be made by culture, direct fluorescent antibody staining, serological tests, urinary antigen detection or nucleic acid detection and various subtyping techniques. In order to eradicate L. pneumophila from contaminated water systems several methods are available; Thermal or chemical shock \disinfection, UV irradiation, ozone treatment, silver-copper ionization, anodic oxidation and chlorine dioxide application.
