scholarly journals Legionnaires' Disease Bacterium (Legionella pneumophila) Multiplies Intracellularly in Human Monocytes

1980 ◽  
Vol 66 (3) ◽  
pp. 441-450 ◽  
Author(s):  
Marcus A. Horwitz ◽  
Samuel C. Silverstein
Keyword(s):  
Legionella Pneumophila ◽  
Human Monocytes ◽  
Legionnaires Disease

scholarly journals Formation of a novel phagosome by the Legionnaires' disease bacterium (Legionella pneumophila) in human monocytes.

1983 ◽  
Vol 158 (4) ◽  
pp. 1319-1331 ◽  
Author(s):  
M A Horwitz
Keyword(s):  
Legionella Pneumophila ◽  
Vacuolar Membrane ◽  
Common Mechanism ◽  
Cytoplasmic Vacuole ◽  
Human Monocytes ◽  
Vacuole Formation ◽  
Cytoplasmic Organelles ◽  
Membrane Bound ◽  
Legionnaires Disease ◽  
Intracellular Multiplication

Previous studies have shown that L. pneumophila multiplies intracellularly in human monocytes and alveolar macrophages within a membrane-bound cytoplasmic vacuole studded with ribosomes. In this paper, the formation of this novel vacuole is examined. After entry into monocytes, L. pneumophila resides in a membrane-bound vacuole. During the first hour after entry, vacuoles containing L. pneumophila are found surrounded by smooth vesicles fusing with or budding off from the vacuolar membrane and by mitochondria closely apposed to the vacuolar membrane. By 4 h, vacuoles are found less frequently surrounded by these cytoplasmic organelles, but now ribosomes and rough vesicles are found gathered about the vacuole. By 8 h, the ribosome-lined vacuole has formed. Erythromycin, at concentrations that completely inhibit the intracellular multiplication of L. pneumophila, has no effect on vacuole formation. Formalin-killed L. pneumophila also reside in a membrane-bound vacuole after entry into monocytes. In contrast to the situation with live L. pneumophila, cytoplasmic organelles are not found surrounding vacuoles containing formalin-killed L. pneumophila at any time after entry. Formalin-killed bacteria are rapidly digested, and by 4 h, few remain intact. The L. pneumophila-containing vacuole has certain features in common with other intracellular organisms that inhibit phagosome-lysosome fusion; these organisms may share a common mechanism for vacuole formation and inhibition of phagosome-lysosome fusion.

scholarly journals Characterization of avirulent mutant Legionella pneumophila that survive but do not multiply within human monocytes.

1987 ◽  
Vol 166 (5) ◽  
pp. 1310-1328 ◽  
Author(s):  
M A Horwitz
Keyword(s):  
Legionella Pneumophila ◽  
High Titer ◽  
Serial Passage ◽  
Secretory Protein ◽  
Mononuclear Phagocyte ◽  
Human Monocytes ◽  
Wild Type ◽  
Artificial Medium ◽  
Legionnaires Disease

Legionella pneumophila, the causative agent of Legionnaires' disease, is a Gram-negative bacterium and a facultative intracellular parasite that multiplies in human monocytes and alveolar macrophages. In this paper, mutants of L. pneumophila avirulent for human monocytes were obtained and extensively characterized. The mutants were obtained by serial passage of wild-type L. pneumophila on suboptimal artificial medium. None of 44 such mutant clones were capable of multiplying in monocytes or exerting a cytopathic effect on monocyte monolayers. Under the same conditions, wild-type L. pneumophila multiplied 2.5-4.5 logs, and destroyed the monocyte monolayers. The basis for the avirulent phenotype was an inability of the mutants to multiply intracellularly. Both mutant and wild-type bacteria bound to and were ingested by monocytes, and both entered by coiling phagocytosis. Thereafter, their intracellular destinies diverged. The wild-type formed a distinctive ribosome-lined replicative phagosome, inhibited phagosome-lysosome fusion, and multiplied intracellularly. The mutant did not form the distinctive phagosome nor inhibit phagosome-lysosome fusion. The mutant survived intracellularly but did not replicate in the phagolysosome. In all other respects studied, the mutant and wild-type bacteria were similar. They had similar ultrastructure and colony morphology; both formed colonies of compact and diffuse type. They had similar structural and secretory protein profiles and LPS profile by PAGE. Both the mutant and wild-type bacteria were completely resistant to human complement in the presence or absence of high titer anti-L. pneumophila antibody. The mutant L. pneumophila have tremendous potential for enhancing our understanding of the intracellular biology of L. pneumophila and other parasites that follow a similar pathway through the mononuclear phagocyte. Such mutants also show promise for enhancing our understanding of immunity to L. pneumophila, and they may serve as prototypes in the development of safe and effective vaccines against intracellular pathogens.

scholarly journals Efficacy of SCH27899 in an Animal Model of Legionnaires' Disease Using Immunocompromised A/J Mice

2000 ◽  
Vol 44 (5) ◽  
pp. 1333-1336 ◽  
Author(s):  
Joan K. Brieland ◽  
David Loebenberg ◽  
Fred Menzel ◽  
Roberta S. Hare
Keyword(s):  
Animal Model ◽  
Murine Model ◽  
Legionella Pneumophila ◽  
Immunocompromised Host ◽  
Lung Infection ◽  
Cortisone Acetate ◽  
Contrast Administration ◽  
Once Daily ◽  
Legionnaires Disease ◽  
Lung Infections

ABSTRACT The efficacy of SCH27899, a new everninomicin antibiotic, against replicative Legionella pneumophila lung infections in an immunocompromised host was evaluated using a murine model of Legionnaires' disease. A/J mice were immunocompromised with cortisone acetate and inoculated intratracheally with L. pneumophilaserogroup 1 (105 CFU per mouse). At 24 h postinoculation, mice were administered either SCH27899 (6 to 60 mg/kg [MPK] intravenously) or a placebo once daily for 5 days, and mortality and intrapulmonary growth of L. pneumophila were assessed. In the absence of SCH27899, there was 100% mortality inL. pneumophila-infected mice, with exponential intrapulmonary growth of the bacteria. In contrast, administration of SCH27899 at a dose of ≥30 MPK resulted in ≥90% survival of infected mice, which was associated with inhibition of intrapulmonary growth ofL. pneumophila. In subsequent studies, the efficacy of SCH27899 was compared to ofloxacin (OFX) and azithromycin (AZI). Administration of SCH27899, OFX, or AZI at a dose of ≥30 MPK once daily for 5 days resulted in ≥85% survival of infected mice and inhibition of intrapulmonary growth of the bacteria. However, L. pneumophila CFU were recovered in lung homogenates following cessation of therapy with all three antibiotics. These studies demonstrate that SCH27899 effectively prevents fatal replicativeL. pneumophila lung infection in immunocompromised A/J mice by inhibition of intrapulmonary growth of the bacteria. However, in this murine model of pulmonary legionellosis, SCH27899, like OFX and AZI, was bacteriostatic.

Subtyping ofLegionella pneumophilaisolates by arbitrarily primed polymerase chain reaction

1995 ◽  
Vol 41 (9) ◽  
pp. 846-848 ◽  
Author(s):  
E. Ledesma ◽  
J. Llorca ◽  
M. A. Dasí ◽  
M. L. Camaró ◽  
E. Carbonell ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Legionella Pneumophila ◽  
Water Sources ◽  
Chain Reaction ◽  
Single Room ◽  
Legionnaires Disease ◽  
Polymerase Chain ◽  
Resort Hotel ◽  
Different Water Sources

Arbitrarily primed polymerase chain reaction (AP-PCR) was used to differentiate strains of Legionella pneumophila isolated from different water sources in a resort hotel in Benidorm, Alicante, Spain, where an outbreak of Legionnaires' disease occurred among a group of tourists between 65 and 80 years of age. All isolates were L. pneumophila serogroup 1, subtype Pontiac (Knoxville 1). Five different patterns (P1 to P5) were obtained by AP-PCR. The number of bands per pattern varied between 4 and 11. Patterns P1 and P2 represented 60 and 20% of L. pneumophila isolates, respectively. Since different subpopulations of L. pneumophila coexisted (up to three different AP-PCR patterns were identified in a single room), it was not possible to link an individual L. pneumophila strain to the occurrence of this outbreak.Key words: Legionella pneumophila, AP-PCR, subtyping, outbreak.

scholarly journals Human Lung Tissue Explants Reveal Novel Interactions during Legionella pneumophila Infections

2013 ◽  
Vol 82 (1) ◽  
pp. 275-285 ◽  
Author(s):  
Jens Jäger ◽  
Sebastian Marwitz ◽  
Jana Tiefenau ◽  
Janine Rasch ◽  
Olga Shevchuk ◽  
...  
Keyword(s):  
Lung Tissue ◽  
Legionella Pneumophila ◽  
Human Lung ◽  
Transcriptional Response ◽  
Human Infection ◽  
Bacterial Invasion ◽  
Human Lung Tissue ◽  
Content Type ◽  
Tissue Explants ◽  
Legionnaires Disease

ABSTRACTHistological and clinical investigations describe late stages of Legionnaires' disease but cannot characterize early events of human infection. Cellular or rodent infection models lack the complexity of tissue or have nonhuman backgrounds. Therefore, we developed and applied a novel model forLegionella pneumophilainfection comprising living human lung tissue. We stimulated lung explants withL. pneumophilastrains and outer membrane vesicles (OMVs) to analyze tissue damage, bacterial replication, and localization as well as the transcriptional response of infected tissue. Interestingly, we found that extracellular adhesion ofL. pneumophilato the entire alveolar lining precedes bacterial invasion and replication in recruited macrophages. In contrast, OMVs predominantly bound to alveolar macrophages. Specific damage to septa and epithelia increased over 48 h and was stronger in wild-type-infected and OMV-treated samples than in samples infected with the replication-deficient, type IVB secretion-deficient DotA−strain. Transcriptome analysis of lung tissue explants revealed a differential regulation of 2,499 genes after infection. The transcriptional response included the upregulation of uteroglobin and the downregulation of the macrophage receptor with collagenous structure (MARCO). Immunohistochemistry confirmed the downregulation of MARCO at sites of pathogen-induced tissue destruction. Neither host factor has ever been described in the context ofL. pneumophilainfections. This work demonstrates that the tissue explant model reproduces realistic features of Legionnaires' disease and reveals new functions for bacterial OMVs during infection. Our model allows us to characterize early steps of human infection which otherwise are not feasible for investigations.

How the parasitic bacterium Legionella pneumophila modifies its phagosome and transforms it into rough ER: implications for conversion of plasma membrane to the ER membrane

2001 ◽  
Vol 114 (24) ◽  
pp. 4637-4650 ◽  
Author(s):  
Lewis G. Tilney ◽  
Omar S. Harb ◽  
Patricia S. Connelly ◽  
Camenzind G. Robinson ◽  
Craig R. Roy
Keyword(s):  
Legionella Pneumophila ◽  
Mitochondrial Membranes ◽  
Macrophage Infection ◽  
Thin Sections ◽  
Stage Process ◽  
Legionnaires Disease ◽  
Rough Er ◽  
Membrane Changes ◽  
Phagosomal Membrane

Within five minutes of macrophage infection by Legionella pneumophila, the bacterium responsible for Legionnaires’ disease, elements of the rough endoplasmic reticulum (RER) and mitochondria attach to the surface of the bacteria-enclosed phagosome. Connecting these abutting membranes are tiny hairs, which are frequently periodic like the rungs of a ladder. These connections are stable and of high affinity - phagosomes from infected macrophages remain connected to the ER and mitochondria (as they were in situ) even after infected macrophages are homogenized. Thin sections through the plasma and phagosomal membranes show that the phagosomal membrane is thicker (72±2 Å) than the ER and mitochondrial membranes (60±2 Å), presumably owing to the lack of cholesterol, sphingolipids and glycolipids in the ER. Interestingly, within 15 minutes of infection, the phagosomal membrane changes thickness to resemble that of the attached ER vesicles. Only later (e.g. after six hours) does the ER-phagosome association become less frequent. Instead ribosomes stud the former phagosomal membrane and L. pneumophila reside directly in the rough ER. Examination of phagosomes of various L. pneumophila mutants suggests that this membrane conversion is a four-stage process used by L. pneumophila to establish itself in the RER and to survive intracellularly. But what is particularly interesting is that L. pneumophila is exploiting a poorly characterized naturally occuring cellular process.

scholarly journals Highlighting the Potency of Biosurfactants Produced by Pseudomonas Strains as Anti-Legionella Agents

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Clémence Loiseau ◽  
Emilie Portier ◽  
Marie-Hélène Corre ◽  
Margot Schlusselhuber ◽  
Ségolène Depayras ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Close Association ◽  
Water Systems ◽  
Antagonistic Activity ◽  
Reverse Phase Hplc ◽  
Reverse Phase ◽  
Free Living ◽  
Legionnaires Disease ◽  
Culture Supernatants ◽  
Multispecies Biofilms

Legionella pneumophila, the causative agent of Legionnaires’ disease, is a waterborne bacterium mainly found in man-made water systems in close association with free-living amoebae and multispecies biofilms. Pseudomonas strains, originating from various environments including freshwater systems or isolated from hospitalized patients, were tested for their antagonistic activity towards L. pneumophila. A high amount of tested strains was thus found to be active. This antibacterial activity was correlated to the presence of tensioactive agents in culture supernatants. As Pseudomonas strains were known to produce biosurfactants, these compounds were specifically extracted and purified from active strains and further characterized using reverse-phase HPLC and mass spectrometry methods. Finally, all biosurfactants tested (lipopeptides and rhamnolipids) were found active and this activity was shown to be higher towards Legionella strains compared to various other bacteria. Therefore, described biosurfactants are potent anti-Legionella agents that could be used in the water treatment industry although tests are needed to evaluate how effective they would be under field conditions.

scholarly journals Peptidyl-Prolyl-cis/trans-Isomerases Mip and PpiB ofLegionella pneumophilaContribute to Surface Translocation, Growth at Suboptimal Temperature, and Infection

2018 ◽  
Vol 87 (1) ◽  
Author(s):  
J. Rasch ◽  
C. M. Ünal ◽  
A. Klages ◽  
Ü. Karsli ◽  
N. Heinsohn ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Acanthamoeba Castellanii ◽  
Temperature Tolerance ◽  
Lung Damage ◽  
Atypical Pneumonia ◽  
Content Type ◽  
Wide Range ◽  
Legionnaires Disease ◽  
Environmental Fitness ◽  
Sliding Motility

ABSTRACTThe gammaproteobacteriumLegionella pneumophilais the causative agent of Legionnaires’ disease, an atypical pneumonia that manifests itself with severe lung damage.L. pneumophila, a common inhabitant of freshwater environments, replicates in free-living amoebae and persists in biofilms in natural and man-made water systems. Its environmental versatility is reflected in its ability to survive and grow within a broad temperature range as well as its capability to colonize and infect a wide range of hosts, including protozoa and humans. Peptidyl-prolyl-cis/trans-isomerases (PPIases) are multifunctional proteins that are mainly involved in protein folding and secretion in bacteria. InL. pneumophilathe surface-associated PPIase Mip was shown to facilitate the establishment of the intracellular infection cycle in its early stages. The cytoplasmic PpiB was shown to promote cold tolerance. Here, we set out to analyze the interrelationship of these two relevant PPIases in the context of environmental fitness and infection. We demonstrate that the PPIases Mip and PpiB are important for surfactant-dependent sliding motility and adaptation to suboptimal temperatures, features that contribute to the environmental fitness ofL. pneumophila. Furthermore, they contribute to infection of the natural hostAcanthamoeba castellaniias well as human macrophages and human explanted lung tissue. These effects were additive in the case of sliding motility or synergistic in the case of temperature tolerance and infection, as assessed by the behavior of the double mutant. Accordingly, we propose that Mip and PpiB are virulence modulators ofL. pneumophilawith compensatory action and pleiotropic effects.

scholarly journals Legionnaires' disease in the renal transplant unit of "Hospital das Clinicas, FMUSP": during a five year period (1988-1993)

1994 ◽  
Vol 36 (3) ◽  
pp. 231-236 ◽  
Author(s):  
Neusa Augusta de Oliveira Mazieri ◽  
Cid Vieira Franco de Godoy ◽  
Solange Figueiredo Alves ◽  
Dahir Ramos de Andrade ◽  
Ana Sara S. Levin ◽  
...  
Keyword(s):  
Renal Transplant ◽  
Legionella Pneumophila ◽  
Treatment Interruption ◽  
Immunofluorescence Assay ◽  
High Susceptibility ◽  
Water Decontamination ◽  
Transplant Patients ◽  
Antibody Titers ◽  
Legionnaires Disease ◽  
Renal Transplant Patients

Several reports have related Legionella pneumophila with pneumonia in renal transplant patients, however this association has not been systematically documented in Brazil. Therefore this paper reports the incidence, by serologycal assays, of Legionella pneumophila serogroup 1 in these patients during a five year period. For this purpose sera from blood samples of 70 hospitalized patients with pneumonia from the Renal Transplant Unit of Hospital das Clinicas, FMUSP collected at the acute and convalescent phase of infection were submitted to indirect immunofluorescence assay (IFA) to demonstrate anti-Legionella pneumophila serogroup 1 antibodies. Of these 70 patients studied during the period of 1988 to 1993,18 (25.71 %) had significant rises in specific antibody titers for Legionella pneumophila serogroup 1. Incidence was interrupted following Hospital water decontamination procedures, with recurrence of infections after treatment interruption. In this study, the high susceptibility (25.71%) of immunodepressed renal transplant patients to Legionella pneumophila serogroup 1 nosocomial infections is documented. The importance of the implementation and maintenance of water decontamination measures for prophylaxis of the infection is also clearly evident.

Sign in / Sign up

Export Citation Format

Share Document