scholarly journals AttenuatedLegionella pneumophilaSurvives for a Long Period in an Environmental Water Site

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Takashi Nishida ◽  
Natsuko Nakagawa ◽  
Kenta Watanabe ◽  
Takashi Shimizu ◽  
Masahisa Watarai
Keyword(s):  
Legionella Pneumophila ◽  
Biofilm Formation ◽  
Environmental Water ◽  
Cell Number ◽  
Stress Factors ◽  
Clinical Strain ◽  
Serological Tests ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Long Period

Legionella pneumophilais known as a human pathogen and is ubiquitous in natural and artificial aquatic environments. Many studies have revealed the virulence traits ofL. pneumophilausing clinical strains and a number of studies for characterizing environmental strains are also reported. However, the association between the virulence and survivability in the environment is unclear. In the present study,L. pneumophilawas isolated from environmental water sites (Ashiyu foot spa, water fountain, and public bath), and the serogroups of isolated strains were determined by serological tests. Isolated strains were found to belong to serogroups SG1, SG2, SG3, SG4, SG5, SG8, SG9, and SG13. Untypeable strains were also obtained. Isolated strains were used for intracellular growth assay in a human monocytic cell line, THP-1. Among these strains, only an untypeable strain, named AY3, failed to replicate in THP-1. In addition, AY3 was maintained for a long period in an environmental water site, Ashiyu foot spa 2. Further, we compared the characteristics of several strains isolated from Ashiyu foot spa 2 and a clinical strain, Togus-1. AY3 failed to replicate in THP-1 cells but replicated in an amoeba model,Dictyostelium discoideum. Compared with Togus-1, the culturable cell number of environmental strains under stress conditions was higher. Moreover, biofilm formation was assessed, and AY3 showed the same degree of biofilm formation as Togus-1. Biofilm formation, replication in amoebae, and resistance against stress factors would explain the predominance of AY3 at one environmental site. Although the mechanism underlying the difference in the ability of AY3 to replicate in THP-1 cells or amoebae is still unclear, AY3 may abandon the ability to replicate in THP-1 cells to survive in one environment for a long period. Understanding the mechanisms ofL. pneumophilain replication within different hosts should help in the control of Legionnaires’ disease, but further study is necessary.

scholarly journals Low Endotoxic Potential of Legionella pneumophilaLipopolysaccharide due to Failure of Interaction with the Monocyte Lipopolysaccharide Receptor CD14

1998 ◽  
Vol 66 (9) ◽  
pp. 4151-4157 ◽  
Author(s):  
B. Neumeister ◽  
M. Faigle ◽  
M. Sommer ◽  
U. Zähringer ◽  
F. Stelter ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Endotoxin Challenge ◽  
Human Monocytic Cell Line ◽  
Human Monocytic Cell ◽  
Shwartzman Reaction ◽  
Pontiac Fever ◽  
Membrane Bound

ABSTRACT Legionella pneumophila, a gram-negative bacterium causing Legionnaires’ disease and Pontiac fever, was shown to be highly reactive in in vitro gelation of Limulus lysate but not able to induce fever and the local Shwartzman reaction in rabbits and mice. We analyzed the capacity of purified L. pneumophila lipopolysaccharide (LPS-Lp) to induce activation of the human monocytic cell line Mono Mac 6, as revealed by secretion of proinflammatory cytokines and desensitization to subsequent LPS stimulation. We showed that despite normal reactivity of LPS-Lp in theLimulus amoebocyte lysate assay, induction of cytokine secretion in Mono Mac 6 cells and desensitization to an endotoxin challenge required LPS-Lp concentrations 1,000 times higher than for LPS of Salmonella enterica serovar Minnesota. Therefore, we examined the interaction of LPS-Lp with the LPS receptor CD14. We demonstrated that LPS-Lp did not bind to membrane-bound CD14 expressed on transfected CHO cells, nor did it react with soluble CD14. Our results suggest that the low endotoxic potential of LPS-Lp is due to a failure of interaction with the LPS receptor CD14.

scholarly journals Влияние цефтриаксона и тетрациклина на формирование биопленки штаммами Staphylococcus epidermidis

2014 ◽  
Vol 5 (1) ◽  
pp. 7-11
Author(s):  
O. I. Sidashenko ◽  
O. S. Voronkova ◽  
Y. A. Sirokvasha ◽  
A. I. Vinnikov
Keyword(s):  
Biofilm Formation ◽  
Film Formation ◽  
Cell Number ◽  
Biological Properties ◽  
Biochemical Properties ◽  
Clinical Strain ◽  
Biofilm Growth ◽  
Minimal Inhibitory Concentrations ◽  
Film Forming ◽  
Physiological And Biochemical

122 strains of staphylococci were identified. Among the examined 122 clinical strains of staphylococci, 67 strains belonged to coagulase-positive, and 55 strains to the coagulase-negative ones. According to the study of physiological and biochemical properties, it was found that 37 strains (30.3%) belonged to S. epidermidis species. One of the biological properties of many bacteria is the ability to film formation and these strains attract special attention, since it is known that the film antibiotic resistance is higher than in planktonic cultures. It was determined that 20 strains of those under study were film-forming, 17 strains – non-biofilm forming ones. The film was formed during three days, and settled to the bottom of the plate holes. The clinical (Cl) strain of S. epidermidis was sensitive to ceftriaxone and tetracicline. The control (C) strains of S. epidermidis were sensitive to ceftriaxone, tetracycline and sizomicine. The study of biofilm growth for 2, 3 and 4 days of incubation was carried out. The maximum rate of biofilm S. epidermidis C was observed during 2–3 days; there is the most intense increase of cells number from 5.2 × 108 CFU/ml, for S. epidermidis Cl to 5.6 × 108 CFU/ml. The effect of ceftriaxone and tetracycline on biofilm formation by 2 investigation strains of S. epidermidis was found. We determined differences in minimal inhibitory concentrations (MIC) for planktonic cultures and biofilm of strains under study. It was established that MIC antibiotics inhibited the growth of planktonic cultures on average 2 times lower compared to the MIC which inhibited the biofilm formation. MIC for planktonic culture of S. epidermidis Cl defined for ceftriaxone was equal to 10 mg/ml, and for tetracycline – 1 mg/ml. MIC of ceftriaxone for the control strain was equal to 12 mg/ml, MIC of tetracycline – 0.7 mg/ml. MIC values for dynamics biofilm formation of S. epidermidis Cl strain on the plater were as follows: to ceftriaxone – 20 mg/ml and for tetracycline – 2 mg/ml, MIC of ceftriaxone for S. epidermidis C strain – 24 mg/ml, MIC of tetracycline – 1.5 mg/ml. The effect of ceftriaxone and tetracycline was defined to the larger extent, than MIC for biofilm-forming on the plate (10, 50 and 100 times). More effective action of tetracycline was shown for 1- and 2-daily biofilm cultures of S. epidermidis clinical strain. Adding tetracycline concentration of 20 mg/ml in the culture medium of the 1-day biofilm of S. epidermidis Cl strain reduced the cell number of biofilm formation 590 times, increasing concentrations of tetracycline to 100 mg/ml and added to the 1-day biofilm of the clinical strain reduced the number of bacterial cell 4400 times compared with control. 

Effect of adrenaline and glucocorticoids on monocyte cAMP-specific phosphodiesterase (PDE4) in a monocytic cell line

2002 ◽  
Vol 294 (4) ◽  
pp. 190-197 ◽  
Author(s):  
Mercedes Delgado ◽  
Soledad M. Fernández-Alfonso ◽  
José Fuentes
Keyword(s):  
Cell Line ◽  
Monocytic Cell ◽  
Monocytic Cell Line

scholarly journals Meningococcal Outer Membrane Vesicle Composition-Dependent Activation of the Innate Immune Response

2016 ◽  
Vol 84 (10) ◽  
pp. 3024-3033 ◽  
Author(s):  
Afshin Zariri ◽  
Joep Beskers ◽  
Bas van de Waterbeemd ◽  
Hendrik Jan Hamstra ◽  
Tim H. E. Bindels ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Outer Membrane ◽  
Lipid A ◽  
Membrane Vesicle ◽  
Outer Membrane Vesicles ◽  
Factor H ◽  
Innate Immune ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Detergent Treatment

Meningococcal outer membrane vesicles (OMVs) have been extensively investigated and successfully implemented as vaccines. They contain pathogen-associated molecular patterns, including lipopolysaccharide (LPS), capable of triggering innate immunity. However,Neisseria meningitidiscontains an extremely potent hexa-acylated LPS, leading to adverse effects when its OMVs are applied as vaccines. To create safe OMV vaccines, detergent treatment is generally used to reduce the LPS content. While effective, this method also leads to loss of protective antigens such as lipoproteins. Alternatively, genetic modification of LPS can reduce its toxicity. In the present study, we have compared the effects of standard OMV isolation methods using detergent or EDTA with those of genetic modifications of LPS to yield a penta-acylated lipid A (lpxL1andpagL) on thein vitroinduction of innate immune responses. The use of detergent decreased both Toll-like receptor 4 (TLR4) and TLR2 activation by OMVs, while the LPS modifications reduced only TLR4 activation. Mutational removal of PorB or lipoprotein factor H binding protein (fHbp), two proteins known to trigger TLR2 signaling, had no effect, indicating that multiple TLR2 ligands are removed by detergent treatment. Detergent-treated OMVs andlpxL1OMVs showed similar reductions of cytokine profiles in the human monocytic cell line MM6 and human dendritic cells (DCs). OMVs with the alternative penta-acylated LPS structure obtained after PagL-mediated deacylation showed reduced induction of proinflammatory cytokines interleukin-6 (IL-6) and IL-1β but not of IP-10, a typical TRIF-dependent chemokine. Taken together, these data show that lipid A modification can be used to obtain OMVs with reduced activation of innate immunity, similar to what is found after detergent treatment.

Pro-inflammatory potential of wood smoke and traffic-derived particles in a monocytic cell line

Toxicology ◽  
2008 ◽  
Vol 247 (2-3) ◽  
pp. 123-132 ◽  
Author(s):  
Anette Kocbach ◽  
Ellen Namork ◽  
Per E. Schwarze
Keyword(s):  
Cell Line ◽  
Wood Smoke ◽  
Monocytic Cell ◽  
Monocytic Cell Line

scholarly journals Detection of Protozoan Hosts for Legionella pneumophila in Engineered Water Systems by Using a Biofilm Batch Test

2010 ◽  
Vol 76 (21) ◽  
pp. 7144-7153 ◽  
Author(s):  
Rinske M. Valster ◽  
Bart A. Wullings ◽  
Dick van der Kooij
Keyword(s):  
Legionella Pneumophila ◽  
Biofilm Formation ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Batch Test ◽  
Free Living ◽  
Water Types ◽  
Operational Taxonomic Units ◽  
Hartmannella Vermiformis

ABSTRACT Legionella pneumophila proliferates in aquatic habitats within free-living protozoa, 17 species of which have been identified as hosts by using in vitro experiments. The present study aimed at identifying protozoan hosts for L. pneumophila by using a biofilm batch test (BBT). Samples (600 ml) collected from 21 engineered freshwater systems, with added polyethylene cylinders to promote biofilm formation, were inoculated with L. pneumophila and subsequently incubated at 37°C for 20 days. Growth of L. pneumophila was observed in 16 of 18 water types when the host protozoan Hartmannella vermiformis was added. Twelve of the tested water types supported growth of L. pneumophila or indigenous Legionella anisa without added H. vermiformis. In 12 of 19 BBT flasks H. vermiformis was indicated as a host, based on the ratio between maximum concentrations of L. pneumophila and H. vermiformis, determined with quantitative PCR (Q-PCR), and the composition of clone libraries of partial 18S rRNA gene fragments. Analyses of 609 eukaryotic clones from the BBTs revealed that 68 operational taxonomic units (OTUs) showed the highest similarity to free-living protozoa. Forty percent of the sequences clustering with protozoa showed ≥99.5% similarity to H. vermiformis. None of the other protozoa serving as hosts in in vitro studies were detected in the BBTs. In several tests with growth of L. pneumophila, the protozoa Diphylleia rotans, Echinamoeba thermarum, and Neoparamoeba sp. were identified as candidate hosts. In vitro studies are needed to confirm their role as hosts for L. pneumophila. Unidentified protozoa were implicated as hosts for uncultured Legionella spp. grown in BBT flasks at 15°C.

Sign in / Sign up

Export Citation Format

Share Document