scholarly journals KKL-35 Exhibits Potent Antibiotic Activity against Legionella Species Independently of trans-Translation Inhibition

2017 ◽  
Vol 62 (2) ◽  
Author(s):  
Romain Brunel ◽  
Ghislaine Descours ◽  
Isabelle Durieux ◽  
Patricia Doublet ◽  
Sophie Jarraud ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Messenger Rna ◽  
Antibiotic Activity ◽  
Resistance Development ◽  
Content Type ◽  
Translation Inhibition ◽  
New Family ◽  
Rescue System ◽  
Legionella Species ◽  
Legionnaires Disease

ABSTRACTtrans-Translation is a ribosome-rescue system that is ubiquitous in bacteria. Small molecules defining a new family of oxadiazole compounds that inhibittrans-translation have been found to have broad-spectrum antibiotic activity. We sought to determine the activity of KKL-35, a potent member of the oxadiazole family, against the human pathogenLegionella pneumophilaand other related species that can also cause Legionnaires' disease (LD). Consistent with the essential nature oftrans-translation inL. pneumophila, KKL-35 inhibited the growth of all tested strains at submicromolar concentrations. KKL-35 was also active against other LD-causingLegionellaspecies. KKL-35 remained equally active againstL. pneumophilamutants that have evolved resistance to macrolides. KKL-35 inhibited the multiplication ofL. pneumophilain human macrophages at several stages of infection. No resistant mutants could be obtained, even during extended and chronic exposure. Surprisingly, KKL-35 was not synergistic with other ribosome-targeting antibiotics and did not induce the filamentation phenotype observed in cells defective fortrans-translation. Importantly, KKL-35 remained active againstL. pneumophilamutants expressing an alternate ribosome-rescue system and lacking transfer-messenger RNA, the essential component oftrans-translation. These results indicate that the antibiotic activity of KKL-35 is not related to the specific inhibition oftrans-translation and its mode of action remains to be identified. In conclusion, KKL-35 is an effective antibacterial agent against the intracellular pathogenL. pneumophilawith no detectable resistance development. However, further studies are needed to better understand its mechanism of action and to assess further the potential of oxadiazoles in treatment.

scholarly journals KKL-35 exhibits potent antibiotic activity againstLegionellaspecies independently of trans-translation inhibition

2017 ◽  
Author(s):  
Romain Brunel ◽  
Ghislaine Descours ◽  
Isabelle Durieux ◽  
Patricia Doublet ◽  
Sophie Jarraud ◽  
...  
Keyword(s):  
Small Molecules ◽  
Legionella Pneumophila ◽  
Antibiotic Activity ◽  
Intracellular Pathogen ◽  
Broad Spectrum Antibiotic ◽  
Translation Inhibition ◽  
New Family ◽  
Rescue System ◽  
Legionnaires Disease ◽  
Resistant Mutants

AbstractTrans-translation is a ribosome rescue system that is ubiquitous in bacteria. Small molecules defining a new family of oxadiazole compounds that inhibit trans-translation have been found to have broad-spectrum antibiotic activity. We sought to determine the activity of KKL-35, a potent member of the oxadiazole family, against the human pathogenLegionella pneumophilaand other related species that can also cause Legionnaires disease (LD). Consistent with the essential nature of trans-translation inL. pneumophila, KKL-35 inhibits growth of all tested strains at sub-micromolar concentrations. KKL-35 is also active against other LD-causingLegionellaspecies. KKL-35 remains equally active againstL. pneumophilamutants that have evolved resistance to macrolides. KKL-35 inhibits multiplication ofL. pneumophilain human macrophages at several stages of infection. No resistant mutants could be obtained, even during extended and chronic exposure. Surprisingly, KKL-35 is not synergistic with other ribosome-targeting antibiotics and does not induce the filamentation phenotype observed in cells defective for trans-translation. Importantly, KKL-35 remains active againstL. pneumophilamutants expressing an alternate ribosome-rescue system and lacking tmRNA, the essential component of trans-translation. These results indicate that the antibiotic activity of KKL-35 is not related to the specific inhibition of trans-translation and its mode of action remains to be identified. In conclusion, KKL-35 is an effective antibacterial agent against the intracellular pathogenL. pneumophilaand with no detectable resistance. However, further studies are needed to better understand its mechanism of action and to assess further the potential of oxadiazoles in treatment.

scholarly journals The Legionella pneumophila Metaeffector Lpg2505 (MesI) Regulates SidI-Mediated Translation Inhibition and Novel Glycosyl Hydrolase Activity

2020 ◽  
Vol 88 (5) ◽  
Author(s):  
Ashley M. Joseph ◽  
Adrienne E. Pohl ◽  
Theodore J. Ball ◽  
Troy G. Abram ◽  
David K. Johnson ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Glycosyl Hydrolase ◽  
Protein Translation ◽  
Effector Proteins ◽  
Hydrolase Activity ◽  
Intracellular Replication ◽  
Content Type ◽  
Translation Inhibition ◽  
Legionnaires Disease ◽  
The Impact

ABSTRACT Legionella pneumophila, the etiological agent of Legionnaires’ disease, employs an arsenal of hundreds of Dot/Icm-translocated effector proteins to facilitate replication within eukaryotic phagocytes. Several effectors, called metaeffectors, function to regulate the activity of other Dot/Icm-translocated effectors during infection. The metaeffector Lpg2505 is essential for L. pneumophila intracellular replication only when its cognate effector, SidI, is present. SidI is a cytotoxic effector that interacts with the host translation factor eEF1A and potently inhibits eukaryotic protein translation by an unknown mechanism. Here, we evaluated the impact of Lpg2505 on SidI-mediated phenotypes and investigated the mechanism of SidI function. We determined that Lpg2505 binds with nanomolar affinity to SidI and suppresses SidI-mediated inhibition of protein translation. SidI binding to eEF1A and Lpg2505 is not mutually exclusive, and the proteins bind distinct regions of SidI. We also discovered that SidI possesses GDP-dependent glycosyl hydrolase activity and that this activity is regulated by Lpg2505. We have therefore renamed Lpg2505 MesI (metaeffector of SidI). This work reveals novel enzymatic activity for SidI and provides insight into how intracellular replication of L. pneumophila is regulated by a metaeffector.

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.

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 Development of a DNA Microarray Method for Detection and Identification of All 15 Distinct O-Antigen Forms of Legionella pneumophila

2013 ◽  
Vol 79 (21) ◽  
pp. 6647-6654 ◽  
Author(s):  
Boyang Cao ◽  
Fangfang Yao ◽  
Xiangqian Liu ◽  
Lu Feng ◽  
Lei Wang
Keyword(s):  
Dna Microarray ◽  
Legionella Pneumophila ◽  
Detection Sensitivity ◽  
Immunological Methods ◽  
Clinical Samples ◽  
Content Type ◽  
O Antigen ◽  
Detection And Identification ◽  
Legionnaires Disease ◽  
Reference Strains

ABSTRACTLegionellais ubiquitous in many environments. At least 50 species and 70 serogroups of the Gram-negative bacterium have been identified. Of the 50 species, 20 are pathogenic, andLegionella pneumophilais responsible for the great majority (approximately 90%) of the Legionnaires' disease cases that occur. Furthermore, of the 15L. pneumophilaserogroups identified, O1 alone causes more than 84% of the Legionnaires' disease cases that occur worldwide. Rapid and reliable assays for the detection and identification ofL. pneumophilain water, environmental, and clinical samples are in great demand.L. pneumophilabacteria are traditionally identified by their O antigens by immunological methods. We have recently developed an O serogroup-specific DNA microarray for the detection of all 15 distinct O-antigen forms ofL. pneumophila, including serogroups O1 to O15. A total of 35 strains were used to verify the specificity of the microarray, including 15L. pneumophilaO-antigen standard reference strains and sevenL. pneumophilaclinical isolates as target strains, seven reference strains of other non-pneumophila Legionellaspecies as closely related strains, and six non-Legionellabacterial species as nonrelated strains. The detection sensitivity was 1 ng of genomic DNA or 0.4 CFU/ml in water samples with filter enrichment and plate culturing. This study demonstrated that the microarray allows specific, sensitive, and reproducible detection ofL. pneumophilaserogroups. To the best of our knowledge, this is the first report of a microarray serotyping method for all 15 distinct O-antigen forms ofL. pneumophila.

scholarly journals Utility of PCR, Culture, and Antigen Detection Methods for Diagnosis of Legionellosis

2015 ◽  
Vol 53 (11) ◽  
pp. 3474-3477 ◽  
Author(s):  
Derrick J. Chen ◽  
Gary W. Procop ◽  
Sherilynn Vogel ◽  
Belinda Yen-Lieberman ◽  
Sandra S. Richter
Keyword(s):  
Electronic Medical Records ◽  
Legionella Pneumophila ◽  
Medical Records ◽  
Cleveland Clinic ◽  
Test Methods ◽  
Detection Methods ◽  
Content Type ◽  
Epidemiologic Factors ◽  
Legionnaires Disease ◽  
Positive Results

The goal of this retrospective study was to evaluate the performance of different diagnostic tests for Legionnaires' disease in a clinical setting whereLegionella pneumophilaPCR had been introduced. Electronic medical records at the Cleveland Clinic were searched forLegionellaurinary antigen (UAG), culture, and PCR tests ordered from March 2010 through December 2013. For cases where two or more test methods were performed and at least one was positive, the medical record was reviewed for relevant clinical and epidemiologic factors. Excluding repeat testing on a given patient, 19,912 tests were ordered (12,569 UAG, 3,747 cultures, and 3,596 PCR) with 378 positive results. The positivity rate for each method was 0.4% for culture, 0.8% for PCR, and 2.7% for UAG. For 37 patients, at least two test methods were performed with at least one positive result: 10 (27%) cases were positive by all three methods, 16 (43%) were positive by two methods, and 11 (30%) were positive by one method only. For the 32 patients with medical records available, clinical presentation was consistent with proven or probableLegionellainfection in 84% of the cases. For those cases, the sensitivities of culture, PCR, and UAG were 50%, 92%, and 96%, respectively. The specificities were 100% for culture and 99.9% for PCR and UAG.

scholarly journals Reduction of Legionella spp. in Water and in Soil by a Citrus Plant Extract Vapor

2014 ◽  
Vol 80 (19) ◽  
pp. 6031-6036 ◽  
Author(s):  
Katie Laird ◽  
Elena Kurzbach ◽  
Jodie Score ◽  
Jyoti Tejpal ◽  
George Chi Tangyie ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Water System ◽  
Severe Form ◽  
Gas Chromatography Mass Spectrometry ◽  
Free Living ◽  
Content Type ◽  
Soil Systems ◽  
Viable Cells ◽  
Legionnaires Disease ◽  
Soil And Water

ABSTRACTLegionnaires' disease is a severe form of pneumonia caused byLegionellaspp., organisms often isolated from environmental sources, including soil and water.Legionellaspp. are capable of replicating intracellularly within free-living protozoa, and once this has occurred,Legionellais particularly resistant to disinfectants. Citrus essential oil (EO) vapors are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml−1on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapor againstLegionellaspp. in water and in soil systems. Reductions of viable cells ofLegionella pneumophila,Legionella longbeachae,Legionella bozemanii, and an intra-amoebal culture ofLegionella pneumophila(water system only) were assessed in soil and in water after exposure to a citrus EO vapor at concentrations ranging from 3.75 mg/liter air to 15g/liter air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapor) was determined in water, and gas chromatography-mass spectrometry (GC-MS) analysis of the antimicrobial components (linalool, citral, and β-pinene) was conducted. There was up to a 5-log cells ml−1reduction inLegionellaspp. in soil after exposure to the citrus EO vapors (15 mg/liter air). The most susceptible strain in water wasL. pneumophila, with a 4-log cells ml−1reduction after 24 h via sintering (15 g/liter air). Sintering the vapor through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapor may go some way in controllingLegionellaspp. from environmental sources.

scholarly journals Comparison of the Novel Immunocatch Legionella Test with Sofia Legionella FIA Assay and with BinaxNOW Legionella Card Assay for Detection ofLegionella pneumophila(Serogroup 1) Antigen in Urine Samples

2019 ◽  
Vol 57 (8) ◽  
Author(s):  
F. Congestrì ◽  
M. Morotti ◽  
R. Vicari ◽  
M. F. Pedna ◽  
M. Sparacino ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Signs And Symptoms ◽  
Laboratory Diagnosis ◽  
Antigen Detection ◽  
Urine Samples ◽  
Urinary Antigen ◽  
Content Type ◽  
High Clinical Suspicion ◽  
Legionnaires Disease ◽  
Urinary Antigen Detection

ABSTRACTLegionnaires’ disease (LD) refers to a serious form of acute pneumonia caused byLegionellaspecies. LD can be difficult to diagnose because the signs and symptoms are nonspecific, and therefore a rapid laboratory diagnosis is of paramount importance. In this study, a recently introduced immunochromatographic test (Immunocatch Legionella; Eiken Chemical Co., Ltd.) forLegionella pneumophila(serogroup 1) urinary antigen detection was compared with the Sofia Legionella fluorescent immunoassay (FIA) (Quidel) (routinely used in our laboratory) and with the widely used BinaxNOW Legionella assay (Alere). A total of 248 urine samples (60 frozen and 188 fresh) were evaluated. All of the samples were collected from patients with high clinical suspicion of Legionnaires’ disease. The three assays were performed simultaneously according to the manufacturers’ instructions. A total of 180 concordant negative and 66 concordant positive results were obtained. Only 2 discrepant results were registered. The sensitivity and specificity of Immunocatch compared with Sofia were, respectively, 98.5% and 99.4%. Cohen's kappa coefficient and overall percent agreement between Immunocatch and Sofia were also calculated and resulted in, respectively, 0.97 and 99.2%. These performances suggest that the Immunocatch test is a useful tool forLegionella pneumophila(serogroup 1) urinary antigen detection.

Legionnaire's disease in postoperative neurosurgical patients

1983 ◽  
Vol 59 (4) ◽  
pp. 596-600 ◽  
Author(s):  
Mark C. Glazier ◽  
Richard B. Kohler ◽  
Robert L. Campbell
Keyword(s):  
Legionella Pneumophila ◽  
Clinical Course ◽  
Clinical Manifestations ◽  
Diagnosis And Treatment ◽  
Surgical Patients ◽  
Content Type ◽  
Neurosurgical Patients ◽  
Legionnaires Disease ◽  
High Doses ◽  
Fine Print

✓ Legionella pneumophila postoperative pneumonia may be an important cause of morbidity and mortality in selected surgical patients. This report presents five postoperative neurosurgical patients in whom the diagnosis of Legionnaires' disease was made. Their clinical course and treatment are presented. Clinical manifestations, methods of diagnosis, and treatment of L. pneumophila pneumonia are discussed. It is pointed out that neurosurgical patients who have received high doses of corticosteroids and who develop nosocomial postoperative pneumonias should be suspected of having Legionnaires' disease.

Recommended Precautions for Patients with Legionnaires' Disease

1982 ◽  
Vol 3 (5) ◽  
pp. 401-404 ◽  
Author(s):  
William R. Jarvis
Keyword(s):  
Antimicrobial Therapy ◽  
Legionella Pneumophila ◽  
Diagnostic Techniques ◽  
Legionella Species ◽  
Legionnaires Disease ◽  
Hospital Acquired

AbstractAs diagnostic techniques for the identification of Legionella species have become readily available, recognition of the pneumonic form of Legionellosis has increased. In particular, cases of hospital-acquired Legionella pneumophila are being identified and this has led to concern over possible person-to-person transmission. In most epidemiologic investigations where a source has been identified, water has been implicated. Person-to-person transmission has not been convincingly documented. Therefore, we discourage expensive or inconvenient special precautions for patients hospitalized with Legionnaires' Disease. Rather, we recommend that such patients be placed in secretion precautions until effective antimicrobial therapy has eradicated the organism.

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