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Annals of Agricultural and... Dec 2023Legionella bacteria are commonly found in natural aquatic environments such as rivers, lakes, ponds and hot springs. Legionella infection occurs through the inhalation...
INTRODUCTION AND OBJECTIVE
Legionella bacteria are commonly found in natural aquatic environments such as rivers, lakes, ponds and hot springs. Legionella infection occurs through the inhalation of water-air aerosol generated, for example, by showers or hot tubs. The most common species responsible for infection is Legionella pneumophila, which can cause Pontiac fever, and Legionnaires' disease, as well as a rare extrapulmonary form. The aim of the study's is to assess the susceptibility of Legionella pneumophila bacteria isolated from water systems of public buildings in Poland to antibiotics and chemotherapeutic agents used in the treatment of Legionellosis pneumonia.
MATERIAL AND METHODS
A total of 100 L. pneumophila strains isolated from public buildings, such as hospitals and water recreation facilities, were used for the study. The drug sensitivity of the following antibiotics was determined: erythromycin, azithromycin, ciprofloxacin, levofloxacin, rifampicin, trimethoprim-sulfamethoxazole and tetracycline. Mean MIC50 and MIC90 values were read using accepted standards.
RESULTS
The highest mean MIC value was obtained for tetracycline 6,130+/-0,353 μg/ml (with a range from 1,500 μg/ml to 16,000 μg/ml. In contrast, the lowest MIC was recorded with rifampicin: 0.020+/-0.037 μg/ml (with a range from 0.016 μg/ml to 0.380 μg/ml).
CONCLUSIONS
The lowest biocidal concentration was found for levofloxacin, the highest for tetracycline. The highest MIC50 and MIC90 values were found for tetracycline and the lowest for rifampicin. The highest biocidal values were found for azithromycin and the lowest for tetracycline.
Topics: Humans; Anti-Bacterial Agents; Legionella pneumophila; Rifampin; Levofloxacin; Azithromycin; Poland; Legionnaires' Disease; Tetracycline; Water; Legionella; Microbial Sensitivity Tests
PubMed: 38153060
DOI: 10.26444/aaem/167934 -
Emerging Infectious Diseases Jan 2024We determined whether the incidence rates of travel-associated Legionnaires' disease (TALD) in hotels in Germany increased after a previous occurrence and whether...
We determined whether the incidence rates of travel-associated Legionnaires' disease (TALD) in hotels in Germany increased after a previous occurrence and whether control measures required by the European Legionnaires' Disease Surveillance Network after a cluster (>2 cases within 2 years) restored the rate to baseline. We analyzed TALD surveillance data from Germany during 2015-2019; a total of 307 TALD cases (163 domestic, 144 nondomestic) in hotels were reported. The incidence rate ratio was 5.5 (95% CI 3.6-7.9) for a second case and 25 (95% CI 11-50) for a third case after a cluster had occurred, suggesting that control measures initiated after the occurrence of TALD clusters might be inadequate to restore the incidence rate to baseline. Our findings indicate that substantial LD preventive measures should be explored by hotels or other accommodations after the first TALD case occurs to reduce the risk for future infections.
Topics: Humans; Incidence; Legionnaires' Disease; Travel; Germany
PubMed: 38146962
DOI: 10.3201/eid3001.231064 -
BioRxiv : the Preprint Server For... Dec 2023Bacterial adhesion is a fundamental process which enables colonisation of niche environments and is key for infection. However, in , the causative agent of Legionnaires'...
Bacterial adhesion is a fundamental process which enables colonisation of niche environments and is key for infection. However, in , the causative agent of Legionnaires' disease, these processes are not well understood. The collagen-like protein (Lcl) is an extracellular peripheral membrane protein that recognises sulphated glycosaminoglycans (GAGs) on the surface of eukaryotic cells, but also stimulates bacterial aggregation in response to divalent cations. Here we report the crystal structure of the Lcl C-terminal domain (Lcl-CTD) and present a model for intact Lcl. Our data reveal that Lcl-CTD forms an unusual dynamic trimer arrangement with a positively charged external surface and a negatively charged solvent exposed internal cavity. Through Molecular Dynamics (MD) simulations, we show how the GAG chondroitin-4-sulphate associates with the Lcl-CTD surface via unique binding modes. Our findings show that Lcl homologs are present across both the Pseudomonadota and Fibrobacterota-Chlorobiota-Bacteroidota phyla and suggest that Lcl may represent a versatile carbohydrate binding mechanism.
PubMed: 38106198
DOI: 10.1101/2023.12.10.570962 -
Journal of Epidemiology Dec 2023Legionella pneumonia, a severe form of pneumonia, is caused by Legionella bacteria. The epidemiology of Legionnaires' disease in Japan, including seasonal trends, risk...
BACKGROUND
Legionella pneumonia, a severe form of pneumonia, is caused by Legionella bacteria. The epidemiology of Legionnaires' disease in Japan, including seasonal trends, risk factors for severe disease, and fatality rates, is unclear. This study examined the epidemiology of Legionella pneumonia in Japan.
METHODS
This retrospective cohort study included data of adult patients hospitalized for Legionella pneumonia (identified using the ICD-10 code, A481) in the Japanese Diagnosis Procedure Combination inpatient database, from April 2011 to March 2021. We performed multivariable logistic regression analysis to explore the prognostic factors of in-hospital mortality.
RESULTS
Of 7370 enrolled hospitalized patients from 1140 hospitals (male, 84.4%; aged >50 years, 87.9%), 469 (6.4%) died during hospitalization. The number of hospitalized patients increased yearly, from 658 in 2016 to 975 in 2020. Multivariable logistic regression analysis revealed that higher in-hospital mortality was associated with older age, male sex, lower body mass index, worsened level of consciousness, comorbidities (congestive heart failure, chronic renal diseases, and metastasis), hospitalization from November to May, and ambulance use. However, lower in-hospital mortality was associated with comorbidity (liver diseases), hospitalization after 2013, and hospitalization in hospitals with higher case volume.
CONCLUSIONS
The characterized epidemiology of Legionella pneumonia in Japan revealed a high mortality rate of 6.4%. To the best of our knowledge, this is the first study to demonstrate a higher mortality rate in winter and in patients with congestive heart failure and metastasis. Further research is needed to understand the complex interplay between the prognostic factors of Legionella pneumonia.
PubMed: 38105002
DOI: 10.2188/jea.JE20230178 -
Infection and Immunity Jan 2024is a common intracellular parasitic bacterium that infects humans via the respiratory tract, causing Legionnaires' disease, with fever and pneumonia as the main...
is a common intracellular parasitic bacterium that infects humans via the respiratory tract, causing Legionnaires' disease, with fever and pneumonia as the main symptoms. The emergence of highly virulent and azithromycin-resistant is a major challenge in clinical anti-infective therapy. The CRISPR-Cas acquired immune system provides immune defense against foreign nucleic acids and regulates strain biological functions. However, the distribution of the CRISPR-Cas system in and how it regulates gene expression in remain unclear. Herein, we assessed 915 whole-genome sequences to determine the distribution characteristics of the CRISPR-Cas system and constructed gene deletion mutants to explore the regulation of the system based on growth ability , antibiotic sensitivity, and intracellular proliferation of . The CRISPR-Cas system in was predominantly Type II-B and was mainly concentrated in the genome of ST1 strains. The Type II-B CRISPR-Cas system showed no effect on the strain's growth ability but significantly reduced resistance to azithromycin and decreased proliferation ability due to regulation of the efflux pump and the Dot/Icm type IV secretion system. Thus, the Type II-B CRISPR-Cas system plays a crucial role in regulating the virulence of . This expands our understanding of drug resistance and pathogenicity in , provides a scientific basis for the prevention of Legionnaires' disease outbreaks and the rational use of clinical drugs, and facilitates effective treatment of Legionnaires' disease.
Topics: Humans; Legionnaires' Disease; Legionella; Azithromycin; CRISPR-Cas Systems; Legionella pneumophila
PubMed: 38099659
DOI: 10.1128/iai.00229-23 -
ELife Dec 2023Identifying virulence-critical genes from pathogens is often limited by functional redundancy. To rapidly interrogate the contributions of combinations of genes to a...
Identifying virulence-critical genes from pathogens is often limited by functional redundancy. To rapidly interrogate the contributions of combinations of genes to a biological outcome, we have developed a ltiplex, andomized RISPR nterference equencing (MuRCiS) approach. At its center is a new method for the randomized self-assembly of CRISPR arrays from synthetic oligonucleotide pairs. When paired with PacBio long-read sequencing, MuRCiS allowed for near-comprehensive interrogation of all pairwise combinations of a group of 44 virulence genes encoding highly conserved transmembrane proteins for their role in pathogenesis. Both amoeba and human macrophages were challenged with bearing the pooled CRISPR array libraries, leading to the identification of several new virulence-critical combinations of genes. and were particularly fascinating for their apparent redundant functions during human macrophage infection, while alone was essential for virulence in the amoeban host . Thus, MuRCiS provides a method for rapid genetic examination of even large groups of redundant genes, setting the stage for application of this technology to a variety of biological contexts and organisms.
Topics: Humans; Macrophages; Legionella pneumophila; Acanthamoeba castellanii; Virulence; Legionnaires' Disease; Bacterial Proteins
PubMed: 38095310
DOI: 10.7554/eLife.86903 -
MMWR. Morbidity and Mortality Weekly... Dec 2023Legionnaires disease is a serious infection acquired by inhalation of water droplets from human-made building water systems that contain Legionella bacteria. On July 11...
Legionnaires disease is a serious infection acquired by inhalation of water droplets from human-made building water systems that contain Legionella bacteria. On July 11 and 12, 2022, Napa County Public Health (NCPH) in California received reports of three positive urinary antigen tests for Legionella pneumophila serogroup 1 in the town of Napa. By July 21, six Legionnaires disease cases had been confirmed among Napa County residents, compared with a baseline of one or two cases per year. NCPH requested assistance from the California Department of Public Health (CDPH) and CDC to aid in the investigations. Close temporal and geospatial clustering permitted a focused environmental sampling strategy of high-risk facilities which, coupled with whole genome sequencing results from samples and investigation of water system maintenance, facilitated potential linking of the outbreak with an environmental source. NCPH, with technical support from CDC and CDPH, instructed and monitored remediation practices for all environmental locations that tested positive for Legionella. The investigation response to this community outbreak illustrates the importance of interdisciplinary collaboration by public health agencies, laboratory support, timely communication with the public, and cooperation of managers of potentially implicated water systems. Timely identification of possible sources, sampling, and remediation of any facility testing positive for Legionella is crucial to interrupting further transmission.
Topics: Humans; Legionnaires' Disease; Legionella pneumophila; Legionella; Disease Outbreaks; Water Microbiology; California; Water
PubMed: 38060434
DOI: 10.15585/mmwr.mm7249a1 -
BioRxiv : the Preprint Server For... Nov 2023is an accidental human bacterial pathogen that infects and replicates within alveolar macrophages causing a severe atypical pneumonia known as Legionnaires' disease. As...
is an accidental human bacterial pathogen that infects and replicates within alveolar macrophages causing a severe atypical pneumonia known as Legionnaires' disease. As a prototypical vacuolar pathogen establishes a unique endoplasmic reticulum (ER)-derived organelle within which bacterial replication takes place. Bacteria-derived proteins are deposited in the host cytosol and in the lumen of the pathogen-occupied vacuole via a type IVb (T4bSS) and a type II (T2SS) secretion system respectively. These secretion system effector proteins manipulate multiple host functions to facilitate intracellular survival of the bacteria. Subversion of host membrane glycerophospholipids (GPLs) by the internalized bacteria via distinct mechanisms feature prominently in trafficking and biogenesis of the -containing vacuole (LCV). Conventional GPLs composed of a glycerol backbone linked to a polar headgroup and esterified with two fatty acids constitute the bulk of membrane lipids in eukaryotic cells. The acyl chain composition of GPLs dictates phase separation of the lipid bilayer and therefore determines the physiochemical properties of biological membranes - such as membrane disorder, fluidity and permeability. In mammalian cells, fatty acids esterified in membrane GPLs are sourced endogenously from synthesis or via internalization from the exogenous pool of lipids present in serum and other interstitial fluids. Here, we exploited the preferential utilization of exogenous fatty acids for GPL synthesis by macrophages to reprogram the acyl chain composition of host membranes and investigated its impact on LCV homeostasis and intracellular replication. Using saturated fatty acids as well as - and - isomers of monounsaturated fatty acids we discovered that under conditions promoting lipid packing and membrane rigidification intracellular replication was significantly reduced. Palmitoleic acid - a C16:1 monounsaturated fatty acid - that promotes membrane disorder when enriched in GPLs significantly increased bacterial replication within human and murine macrophages but not in axenic growth assays. Lipidome analysis of infected macrophages showed that treatment with exogenous palmitoleic acid resulted in membrane acyl chain reprogramming in a manner that promotes membrane disorder and live-cell imaging revealed that the consequences of increasing membrane disorder impinge on several LCV homeostasis parameters. Collectively, we provide experimental evidence that replication within its intracellular niche is a function of the lipid bilayer disorder and hydrophobic thickness.
PubMed: 38045297
DOI: 10.1101/2023.11.19.567753 -
Annals of Clinical Microbiology and... Nov 2023Legionnaires' Disease (LD) rarely evolves into pulmonary abscesses. The current systematic review has been designed to explore therapeutical strategies in pulmonary... (Review)
Review
BACKGROUND
Legionnaires' Disease (LD) rarely evolves into pulmonary abscesses. The current systematic review has been designed to explore therapeutical strategies in pulmonary cavitary LD.
METHODS
A research strategy was developed and applied to the databases Embase, Pubmed, and Web of Science from the 1st of January 2000 to the 1st of November 2022. Original articles, case series, case reports, and guidelines written in English, French, German, Italian, and Dutch were considered. Furthermore, medical records of patients treated at the University Hospital UZ Brussel for LD cavitary pneumonia, between the 1st of January 2016 to the 1st of January 2022, were reviewed.
RESULTS
Two patients were found by the UZ Brussel's medical records investigation. Through the literature review, 23 reports describing 29 patients, and seven guidelines were identified. The overall evidence level was low.
RESULT OF SYNTHESIS (CASE REPORTS)
The median age was 48 years and 65% were male. A polymicrobial infection was detected in 11 patients (44%) with other aerobic bacteria being the most commonly found. At diagnosis, 52% of patients received combination therapy, and fluoroquinolones were the preferred antimicrobial class. Anaerobic coverage was neglected in 33% of patients.
RESULT OF SYNTHESIS (GUIDELINES)
Three guidelines favor monotherapy with fluoroquinolones or macrolides, while one suggested an antimicrobial combination in case of severe LD. Four guidelines recommended anaerobic coverage in case of lung abscesses.
CONCLUSION
To date, the evidence supporting cavitary LD treatment is low. Monotherapy lowers toxicity and might be as effective as combination therapy. Finally, anaerobes should not be neglected.
Topics: Humans; Male; Middle Aged; Female; Legionnaires' Disease; Pneumonia; Anti-Bacterial Agents; Fluoroquinolones; Macrolides
PubMed: 38031167
DOI: 10.1186/s12941-023-00652-5 -
Japanese Journal of Infectious Diseases Mar 2024Legionella pneumophila serogroup (SG) 1, the main cause of Legionnaires' disease, can be diagnosed using urinary antigen testing kits. However, lower respiratory tract...
Legionella pneumophila serogroup (SG) 1, the main cause of Legionnaires' disease, can be diagnosed using urinary antigen testing kits. However, lower respiratory tract specimen cultures are required to identify L. pneumophila SG 2-15. We attempted to detect L. pneumophila SG-specific genes in a culture-negative sputum specimen from a patient with pneumonia who was suspected to have Legionnaires' disease. Two multiplex PCR methods targeting L. pneumophila were modified and amplicons considered to be SG13 specific were detected. Direct sequencing revealed that the amplicons were identical to the nucleotide sequence of L. pneumophila SG13. Based on the presentation and clinical course (fever, muscle pain, disturbance of consciousness, high C-reactive protein titer, rhabdomyolysis, hypophosphatemia, and symptomatic improvement with levofloxacin treatment), in combination with the detection of L. pneumophila SG-specific genes, we suspected L. pneumophila SG13 pneumonia. L. pneumophila non-SG1 pneumonia is thought to be underestimated because of its difficult laboratory diagnosis. The modified multiplex PCR system for lower respiratory tract specimens revealed in this study is likely to improve the diagnosis of Legionnaires' disease caused by L. pneumophila SG13 and other SGs.
Topics: Humans; Legionella pneumophila; Legionnaires' Disease; Serogroup; Sputum; Pneumonia
PubMed: 38030269
DOI: 10.7883/yoken.JJID.2023.302