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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 -
Applied and Environmental Microbiology Feb 2022Legionella pneumophila widely exists in natural and artificial water environments, which enables it to infect people. L. pneumophila infection causes Legionnaires'...
Legionella pneumophila widely exists in natural and artificial water environments, which enables it to infect people. L. pneumophila infection causes Legionnaires' disease (LD), which is a significant but relatively uncommon respiratory infection. Approximately 90% of LD is caused by L. pneumophila serogroup 1 (Lp1). Meteorological conditions may affect the infectivity and virulence of Lp1, but the exact relationship between them is still unclear. In this study, we evaluated the virulence of Lp1 by screening of total 156 Lp1 strains isolated from cooling tower water in different regions of China by detecting their abilities to activate NF-κB signaling pathway . In addition, we screened the distribution of some selected virulence genes in these strains. The virulence, virulence gene distribution, and the meteorological factors were analyzed. We found that both the virulence and the distribution of virulence genes had a certain regional and meteorological correlation. Although the loss of several virulence genes showed significant effects on the virulence of Lp1 strains, the distribution of virulence genes had very limited effects on the virulence of Lp1. LD is likely to be underrecognized in many countries. Due to the widespread existence of L. pneumophila in natural and artificial water environments and to the lack of cross-protection against different strains, L. pneumophila is a potentially serious threat to human health. Therefore, effective monitoring of the virulence of L. pneumophila in the water environment is very important to prevent and control the prevalence of LD. Understanding the virulence of L. pneumophila can not only help us to predict the risk of possible outbreaks in advance but can also enable more targeted clinical treatment. This study highlights the importance of understanding the epidemiology and ecology of L. pneumophila isolated from public facilities in terms of public health and biology. Due to the potential for water sources to harbor and disseminate L. pneumophila and to the fact that geographical conditions influence the virulence of L. pneumophila, timely and accurate L. pneumophila virulence surveillance is urgently needed.
Topics: China; Disease Outbreaks; Ecology; Humans; Legionella pneumophila; Legionnaires' Disease; Water Microbiology
PubMed: 34818106
DOI: 10.1128/AEM.01921-21 -
International Journal of Molecular... Sep 2023is the primary causative agent of Legionnaires' disease. The mutant-type strain interrupted in the ORF7 gene region responsible for the lipopolysaccharide biosynthesis...
is the primary causative agent of Legionnaires' disease. The mutant-type strain interrupted in the ORF7 gene region responsible for the lipopolysaccharide biosynthesis of the strain Heysham-1, lacking the -acetyl groups attached to the rhamnose of the core part, showed a higher surface polarity compared with the wild-type strain. The measurement of excitation energy transfer between fluorophores located on the surface of bacteria and eukaryotic cells showed that, at an early stage of interaction with host cells, the mutant exhibited weaker interactions with cells and THP-1-derived macrophages. The mutant displayed reduced adherence to macrophages but enhanced adherence to , suggesting that the -acetyl group of the LPS core region plays a crucial role in facilitating interaction with macrophages. The lack of core rhamnose -acetyl groups made it easier for the bacteria to multiply in amoebae and macrophages. The mutant induced TNF-α production more strongly compared with the wild-type strain. The mutant synthesized twice as many ceramides Cer(t34:0) and Cer(t38:0) than the wild-type strain. The study showed that the internal sugars of the LPS core region of sg 1 can interact with eukaryotic cell surface receptors and mediate in contacting and attaching bacteria to host cells as well as modulating the immune response to infection.
Topics: Humans; Legionella pneumophila; Lipopolysaccharides; Rhamnose; Serogroup; Bacterial Proteins; Legionnaires' Disease
PubMed: 37834049
DOI: 10.3390/ijms241914602 -
Journal of Travel Medicine 2015Travel-associated Legionnaires' disease (LD) is a serious problem, and hundreds of cases are reported every year among travelers who stayed at hotels, despite the... (Review)
Review
BACKGROUND
Travel-associated Legionnaires' disease (LD) is a serious problem, and hundreds of cases are reported every year among travelers who stayed at hotels, despite the efforts of international and governmental authorities and hotel operators to prevent additional cases.
METHODS
A systematic review of travel-associated LD events (cases, clusters, outbreaks) and of environmental studies of Legionella contamination in accommodation sites was conducted. Two databases were searched (PubMed and EMBASE). Data were extracted from 50 peer-reviewed articles that provided microbiological and epidemiological evidence for linking the accommodation sites with LD. The strength of evidence was classified as strong, possible, and probable.
RESULTS
Three of the 21 hotel-associated events identified and four of nine ship-associated events occurred repeatedly on the same site. Of 197 hotel-associated cases, 158 (80.2%) were linked to hotel cooling towers and/or potable water systems. Ship-associated cases were most commonly linked to hot tubs (59/83, 71.1%). Common contributing factors included inadequate disinfection, maintenance, and monitoring; water stagnation; poor temperature control; and poor ventilation. Across all 30 events, Legionella concentrations in suspected water sources were >10,000 cfu/L, <10,000 cfu/L, and unknown in 11, 3, and 13 events, respectively. In five events, Legionella was not detected only after repeated disinfections. In environmental studies, Legionella was detected in 81.1% of ferries (23/28) and 48.9% of hotels (587/1,200), while all 12 cruise ships examined were negative.
CONCLUSIONS
This review highlights the need for LD awareness strategies targeting operators of accommodation sites. Increased standardization of LD investigation and reporting, and more rigorous follow-up of LD events, would help generate stronger, more comparable evidence on LD sources, contributing factors, and control measure effectiveness.
Topics: Disease Outbreaks; Humans; Legionella pneumophila; Legionnaires' Disease; Risk Factors; Ships; Travel
PubMed: 26220258
DOI: 10.1111/jtm.12225 -
Frontiers in Cellular and Infection... 2018is a gram-negative bacterium that inhabits freshwater ecosystems, where it is present in biofilm or as planktonic form. is mainly found associated with protozoa, which... (Review)
Review
is a gram-negative bacterium that inhabits freshwater ecosystems, where it is present in biofilm or as planktonic form. is mainly found associated with protozoa, which serve as protection from hostile environments and as replication niche. If inhaled within aerosols, is also able to infect and replicate in human alveolar macrophages, eventually causing the Legionnaires' disease. The transition between intracellular and extracellular environments triggers a differentiation program in which metabolic as well as morphogenetic changes occur. We here describe the current knowledge on how the different developmental states of this bacterium are regulated, with a particular emphasis on the stringent response activated during the transition from the replicative phase to the infectious phase and the metabolic features going in hand. We propose that the cellular differentiation of this intracellular pathogen is closely associated to key metabolic changes in the bacterium and the host cell, which together have a crucial role in the regulation of virulence.
Topics: Animals; Energy Metabolism; Environment; Host-Pathogen Interactions; Humans; Legionella pneumophila; Legionnaires' Disease; Life Cycle Stages; Metabolic Networks and Pathways; Virulence
PubMed: 29404281
DOI: 10.3389/fcimb.2018.00003 -
Water Research Aug 2019Cooling towers for heating, ventilation and air conditioning are ubiquitous in the built environment. Often located on rooftops, their semi-open water basins provide a... (Review)
Review
Cooling towers for heating, ventilation and air conditioning are ubiquitous in the built environment. Often located on rooftops, their semi-open water basins provide a suitable environment for microbial growth. They are recognized as a potential source of bacterial pathogens and have been associated with disease outbreaks such as Legionnaires' disease. While measures to minimize public health risks are in place, the general microbial and protist community structure and dynamics in these systems remain largely elusive. In this study, we analysed the microbiome of the bulk water from the basins of three cooling towers by 16S and 18S rRNA gene amplicon sequencing over the course of one year. Bacterial diversity in all three towers was broadly comparable to other freshwater systems, yet less diverse than natural environments; the most abundant taxa are also frequently found in freshwater or drinking water. While each cooling tower had a pronounced site-specific microbial community, taxa shared among all locations mainly included groups generally associated with biofilm formation. We also detected several groups related to known opportunistic pathogens, such as Legionella, Mycobacterium, and Pseudomonas species, albeit at generally low abundance. Although cooling towers represent a rather stable environment, microbial community composition was highly dynamic and subject to seasonal change. Protists are important members of the cooling tower water microbiome and known reservoirs for bacterial pathogens. Co-occurrence analysis of bacteria and protist taxa successfully captured known interactions between amoeba-associated bacteria and their hosts, and predicted a large number of additional relationships involving ciliates and other protists. Together, this study provides an unbiased and comprehensive overview of microbial diversity of cooling tower water basins, establishing a framework for investigating and assessing public health risks associated with these man-made freshwater environments.
Topics: Humans; Legionella; Legionnaires' Disease; Microbiota; Seasons; Water; Water Microbiology
PubMed: 31128471
DOI: 10.1016/j.watres.2019.04.028 -
Frontiers in Cellular and Infection... 2020Many Gram-negative bacterial pathogens employ translocated virulence factors, termed effector proteins, to facilitate their parasitism of host cells and evade host... (Review)
Review
Many Gram-negative bacterial pathogens employ translocated virulence factors, termed effector proteins, to facilitate their parasitism of host cells and evade host anti-microbial defenses. However, eukaryotes have evolved to detect effector-mediated virulence strategies through a phenomenon termed effector-triggered immunity (ETI). Although ETI was discovered in plants, a growing body of literature demonstrates that metazoans also utilize effector-mediated immunity to detect and clear bacterial pathogens. This mini review is focused on mechanisms of effector-mediated immune responses by the accidental human pathogen . We highlight recent advancements in the field and discuss the future prospects of harnessing effectors for the development of novel therapeutics, a critical need due to the prevalence and rapid spread of antibiotic resistance.
Topics: Bacterial Proteins; Host-Pathogen Interactions; Humans; Legionella pneumophila; Legionnaires' Disease; Virulence; Virulence Factors
PubMed: 33614523
DOI: 10.3389/fcimb.2020.593823 -
PloS One 2020The performances of the ImmuView Streptococcus pneumoniae (Sp) and Legionella pneumophila (Lp) urinary antigen test were compared to that of the BinaxNOW Sp and Lp...
Performance of the ImmuView and BinaxNOW assays for the detection of urine and cerebrospinal fluid Streptococcus pneumoniae and Legionella pneumophila serogroup 1 antigen in patients with Legionnaires' disease or pneumococcal pneumonia and meningitis.
The performances of the ImmuView Streptococcus pneumoniae (Sp) and Legionella pneumophila (Lp) urinary antigen test were compared to that of the BinaxNOW Sp and Lp assays, using frozen urine from 166 patients with Legionnaires' disease (LD) and 59 patients with pneumococcal pneumonia. Thirty Sp-positive or contrived cerebrospinal fluids (CSF) were also tested. Test specimens were collected and tested at different sites, with each site testing unique specimens by technologists blinded to expected results. No significant differences in test concordances were detected for the ImmuView and BinaxNOW assays for the Sp or Lp targets for urine from patients with pneumococcal pneumonia or LD when performance from both sites were combined. At one of two test sites the ImmuView Lp assay was more sensitive than the BinaxNOW assay, with no correlation between test performance and Lp serogroup 1 monoclonal type. Urines from six of seven patients with LD caused by Legionella spp. bacteria other than Lp serogroup 1 were negative in both assays. Both tests had equivalent performance for Sp-positive CSF. The clinical sensitivities for pneumococcal pneumonia were 88.1 and 94.4% for the ImmuView and Binax assays, and 87.6 and 84.2% for the Lp assays, respectively. Test specificities for pneumococcal pneumonia were 96.2 and 97.0% for the ImmuView and Binax assays, and 99.6 and 99.1% for the Lp assays. Both assays were highly specific for Sp in pediatric urines from children with nasopharyngeal colonization by the bacterium. ImmuView and BinaxNOW assay performance was equivalent in these studies.
Topics: Adolescent; Adult; Antigens, Bacterial; Biological Assay; Cerebrospinal Fluid; Child; Child, Preschool; Female; Humans; Immunologic Tests; Infant; Legionella pneumophila; Legionnaires' Disease; Male; Meningitis; Pneumonia, Pneumococcal; Sensitivity and Specificity; Serogroup; Streptococcus pneumoniae; Urine; Young Adult
PubMed: 32866217
DOI: 10.1371/journal.pone.0238479 -
The American Journal of Case Reports Dec 2019BACKGROUND Legionella pneumonia can be an aggressive form of pneumonia. However, it is rare in pregnant women, particularly in the peripartum period. To the best of our...
BACKGROUND Legionella pneumonia can be an aggressive form of pneumonia. However, it is rare in pregnant women, particularly in the peripartum period. To the best of our knowledge this is the only case of Legionella pneumonia with endometrial sepsis. We are reporting a patient with this rare condition. CASE REPORT The patient was an 18-year-old female, pregnant with her first baby, who developed symptoms of the common cold near term. The patient was seen at another major facility initially and was discharged home with a diagnosis of "cold". She was still uncomfortable and came to our facility Aront Ogden Medical Center Elmira, NY, USA, where she had rupture of membranes and underwent C-section. She was suspected clinically of having pneumonia. Initial chest x-ray was negative, but computed tomography (CT)-scan did show bilateral pneumonia. Further workup confirmed the diagnosis of Legionella pneumonia and was treated for that as well as for endometritis. She did require Intensive Care Unit (ICU) care during her hospital stay. The patient was seen and evaluated by multiple subspecialties, including Critical Care, Infectious Disease, and Gastroenterology subspecialties. The patient improved steadily, and was later discharged home in the care of her family with a healthy baby and was advised to follow up with her Primary Medical Provider as outpatient. CONCLUSIONS Legionella pneumonia in pregnancy may be more common than we think, and could be easily overlooked in that patient population, have to be in the back mind of medical provider. Overlooking diagnosis could lead to serious adverse consequences for these patients.
Topics: Adolescent; Common Cold; Diagnostic Errors; Female; Humans; Legionnaires' Disease; Pneumonia, Bacterial; Pregnancy; Pregnancy Complications, Infectious; Tomography, X-Ray Computed
PubMed: 31882569
DOI: 10.12659/AJCR.916071 -
The Lancet. Microbe Nov 2022Legionella pneumophila is the main cause of a severe pneumonic illness known as Legionnaires' disease and is a global public health threat. Whole-genome sequencing (WGS)...
BACKGROUND
Legionella pneumophila is the main cause of a severe pneumonic illness known as Legionnaires' disease and is a global public health threat. Whole-genome sequencing (WGS) can be applied to trace environmental origins of L pneumophila infections, providing information to guide appropriate interventions. We aim to explore the evolutionary and epidemiological relationships in a 36-year Scottish L pneumophila reference isolate collection.
METHODS
We investigated the genomic epidemiology of Legionnaires' disease over 36 years in Scotland, comparing genome sequences for all clinical L pneumophila isolates (1984-2020) with a sequence dataset of 3211 local and globally representative isolates. We used a stratified clustering approach to capture epidemiological relationships by core genome Multi-locus Sequence Typing, followed by high-resolution phylogenetic analysis of clusters to measure diversity and evolutionary relatedness in context with epidemiological metadata.
FINDINGS
Clustering analysis showed that 111 (57·5 %) of 193 of L pneumophila infections in Scotland were caused by ten endemic lineages with a wide temporal and geographical distribution. Phylogenetic analysis of L pneumophila identified hospital-associated sublineages that had been detected in the hospital environment up to 19 years. Furthermore, 12 (30·0%) of 40 community-associated infections (excluding a single, large outbreak) that occurred over a 13 year period (from 2000 to 2013) were caused by a single widely distributed endemic clone (ST37), consistent with enhanced human pathogenicity. Finally, our analysis revealed clusters linked by national or international travel to distinct geographical regions, indicating several previously unrecognised travel links between closely related isolates (fewer than five single nucleotide polymorphisms) connected by geography.
INTERPRETATION
Our analysis reveals the existence of previously undetected endemic clones of L pneumophila that existed for many years in hospital, community, and travel-associated environments. In light of these findings, we propose that cluster and outbreak definitions should be reconsidered, and propose WGS-based surveillance as a critical public health tool for real-time identification and mitigation of clinically important endemic clones.
FUNDING
Chief Scientist Office, Biotechnology and Biological Sciences Research Council (UK), Medical Research Council Precision Medicine Doctoral Training Programme, Wellcome Trust, and Medical Research Council (UK).
Topics: Humans; Legionnaires' Disease; Multilocus Sequence Typing; Phylogeny; Travel; Genomics
PubMed: 36240833
DOI: 10.1016/S2666-5247(22)00231-2