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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 -
Polish Archives of Internal Medicine Oct 2023
Topics: Humans; Legionnaires' Disease; Legionella; Poland
PubMed: 37818628
DOI: 10.20452/pamw.16584 -
Frontiers in Microbiology 2023is an opportunistic intracellular pathogen that inhabits artificial water systems and can be transmitted to human hosts by contaminated aerosols. Upon inhalation, it... (Review)
Review
is an opportunistic intracellular pathogen that inhabits artificial water systems and can be transmitted to human hosts by contaminated aerosols. Upon inhalation, it colonizes and grows inside the alveolar macrophages and causes Legionnaires' disease. To effectively control and manage Legionnaires' disease, a deep understanding of the host-pathogen interaction is crucial. Bacterial extracellular vesicles, particularly outer membrane vesicles (OMVs) have emerged as mediators of intercellular communication between bacteria and host cells. These OMVs carry a diverse cargo, including proteins, toxins, virulence factors, and nucleic acids. OMVs play a pivotal role in disease pathogenesis by helping bacteria in colonization, delivering virulence factors into host cells, and modulating host immune responses. This review highlights the role of OMVs in the context of host-pathogen interaction shedding light on the pathogenesis of . Understanding the functions of OMVs and their cargo provides valuable insights into potential therapeutic targets and interventions for combating Legionnaires' disease.
PubMed: 37817751
DOI: 10.3389/fmicb.2023.1270123 -
MBio Oct 2023is an intracellular bacterium responsible of Legionnaires' disease, a severe pneumonia that is often fatal when not treated promptly. The pathogen's ability to...
is an intracellular bacterium responsible of Legionnaires' disease, a severe pneumonia that is often fatal when not treated promptly. The pathogen's ability to efficiently colonize the host resides in its ability to replicate intracellularly. Essential for intracellular replication is translocation of many different protein effectors a specialized secretion system. One of them, called RomA, binds and directly modifies the host chromatin at a unique site (tri-methylation of lysine 14 of histone H3 [H3K14me]). However, the molecular mechanisms of binding are not known. Here, we resolve this question through structural characterization of RomA together with the H3 peptide. We specifically reveal an active role of the ankyrin repeats located in its C-terminal in the interaction with the histone H3 tail. Indeed, without the ankyrin domains, RomA loses its ability to act as histone methyltransferase. These results discover the molecular mechanisms by which a bacterial histone methyltransferase that is conserved in strains acts to modify chromatin.
Topics: Humans; Legionella pneumophila; Chromatin; Histones; Ankyrins; Histone Methyltransferases; Legionnaires' Disease; Bacterial Proteins
PubMed: 37795993
DOI: 10.1128/mbio.01655-23 -
Cureus Aug 2023Toxic shock syndrome is a rare and life-threatening condition that is typically caused by group A Streptococcus or Staphylococcus aureus. It classically presents with...
Toxic shock syndrome is a rare and life-threatening condition that is typically caused by group A Streptococcus or Staphylococcus aureus. It classically presents with fever, hypotension, sunburn-like rash, and multi-organ system failure. We describe a case of a 70-year-old male with this condition who had an atypical presentation of left chest wall pain and left shoulder pain after two mechanical falls along with hemodynamic stability. The patient rapidly deteriorated on his second hospital floor day, resulting in a higher complexity of care and management in the intensive care unit (ICU). Despite a number of resuscitative measures, therapies, and multidisciplinary care, the patient unfortunately passed away within 24 hours of his ICU care.
PubMed: 37791202
DOI: 10.7759/cureus.44429 -
Research Square Sep 2023Ubiquitination is a crucial posttranslational modification in eukaryotes that plays a significant role in the infection of intracellular microbial pathogens, such as...
Ubiquitination is a crucial posttranslational modification in eukaryotes that plays a significant role in the infection of intracellular microbial pathogens, such as the bacterium responsible for Legionnaires' disease. While the -containing vacuole (LCV) is coated with ubiquitin (Ub), it avoids recognition by autophagy adaptors. In this study, we report that the Sdc and Sde families of effectors work together to build ubiquitinated species around the LCV. The Sdc effectors catalyze canonical polyubiquitination directly on host targets or on the phosphoribosyl-Ub (PR-Ub) conjugated to host targets by Sde. Remarkably, the Ub moieties within the poly-Ub chains are either modified with a phosphoribosyl group by Sde and other PDE domain-containing effectors or covalently attached to other host substrates via Sde-mediated PR-ubiquitination. Furthermore, these modifications prevent the recognition by Ub adaptors, such as p62, and therefore exclude host autophagy adaptors from the LCV. Our findings shed light on the nature of the poly-ubiquitinated species present at the surface of the LCV and provide a molecular mechanism for the avoidance of autophagy adaptors by the Ub-decorated LCV.
PubMed: 37790579
DOI: 10.21203/rs.3.rs-3266941/v1 -
Cureus Aug 2023Lemierre's syndrome, also known as anaerobic post-anginal septicemia, necrobacillosis, and the "forgotten disease," is a rare manifestation. It is often presented with...
Lemierre's syndrome, also known as anaerobic post-anginal septicemia, necrobacillosis, and the "forgotten disease," is a rare manifestation. It is often presented with sepsis, sore throat, fever, neck pain, internal jugular vein thrombophlebitis/thrombosis, and septic emboli. The bacteria that are usually associated with the disease are species, but it is also associated with , , and other bacterial species. The diagnosis of Lemierre's syndrome is made based on evidence of septic thrombophlebitis, preceding oropharyngeal infection, and positive culture. Treatment usually consists of antibiotics directed toward the causative organism. The use of anticoagulation, although controversial, is shown to be beneficial by several studies. We describe a middle-aged patient who presented with a sore throat, neck pain, and dysphagia. Imaging of the neck and chest revealed right jugular thrombosis along with septic emboli in the lungs. The culture of the blood and pus drained from the peritonsillar abscess grew . In this study, we have illustrated the effective management of Lemierre's syndrome with antibiotics, anticoagulants, and needle aspiration of abscess.
PubMed: 37779762
DOI: 10.7759/cureus.44311 -
Cureus Aug 2023Legionnaires' disease is an atypical pneumonia caused by Legionella pneumophila ( pneumonia that features slow onset, nonproductive cough, fatigue, headache, sore...
Legionnaires' disease is an atypical pneumonia caused by Legionella pneumophila ( pneumonia that features slow onset, nonproductive cough, fatigue, headache, sore throat, myalgias, and malaise. It can be difficult to diagnose, as it presents with extrapulmonary symptoms, and delay in treatment can be fatal. Here, we present the case of a previously healthy 32-year-old Caucasian male with Legionnaires disease who only presented to the clinic with abdominal pain and diarrhea. The patient did not have any pulmonary symptoms at the initial presentation. This presentation did not fit the diagnostic tools available for Legionnaires' disease, including a validated clinical prediction rule, which ruled out infection with a sensitivity of 97% and a negative predictive value of 99.4%. Due to the complaint of abdominal pain, a flat/upright abdominal X-ray was ordered, which includes a chest X-ray. Upon analyzing the chest X-ray, a right lower lobe consolidation was identified, prompting an urinary test to be added to the lab orders. This case represents the difficulties in diagnosing Legionnaires' disease due to the diverse clinical complexities of presentations, which may solely involve abdominal complaints.
PubMed: 37779758
DOI: 10.7759/cureus.44368 -
Acta Bio-medica : Atenei Parmensis Aug 2023Legionnaires' disease is a severe form of pneumonia caused by the inhalation or aspiration of water droplets contaminated with Legionella pneumophila and other...
BACKGROUND AND AIM
Legionnaires' disease is a severe form of pneumonia caused by the inhalation or aspiration of water droplets contaminated with Legionella pneumophila and other Legionella species. These bacteria are commonly found in natural habitats and man-made water systems. Legionnaires' disease is a significant public health problem, especially in healthcare settings where patients may be exposed to contaminated environmental sources. Nosocomial outbreaks have been reported worldwide, leading to high morbidity and mortality rates, and increased healthcare costs. This study aimed to compare, the clonal relationship of clinical L. pneumophila strains from two different hospitals with L. pneumophila strains isolated from the water supply.
METHODS
In the period from 2019 to 2021, clinical and environmental strains involved in three cases of legionellosis were compared by means of pulsed field gel electrophoresis and sequence based typing techniques.
RESULTS
Our findings highlight the persistence of clonally distinct strains within each hospital examined. Furthermore, the L. pneumophila strains detected from hospital environmental sources were related to the clinical strains isolated, demonstrating the nosocomial origin of these cases.
CONCLUSIONS
Therefore, it is important to implement more accurate surveillance systems both for epidemiological studies and to check the effectiveness of remediation procedures. (www.actabiomedica.it).
Topics: Humans; Legionnaires' Disease; Cross Infection; Legionella pneumophila; Water Supply; Water
PubMed: 37773490
DOI: 10.23750/abm.v94iS3.15048 -
International Journal of Environmental... Sep 2023Travel-associated Legionnaires' disease is a significant public health concern worldwide. A high number of cases are reported every year among travellers who stay at...
Travel-associated Legionnaires' disease is a significant public health concern worldwide. A high number of cases are reported every year among travellers who stay at guest houses, hotels, and spas. Indeed, hot water systems, showers, and air-conditioning systems can be contaminated by , which grows at 25-42 °C. Studies have shown that in Sardinia, especially during the summer months, the water circulation in the hotels' pipes is exposed to extremely high temperatures. As a result, this study was conducted to assess the colonization of hotel water systems by in Sardinia, concerning a recent EU directive 2020/2184 for drinking water with a limit of 1000 CFU /L. Methods. A total of 112 accommodation facilities were analyzed, of which 61.3% were found to be colonized with , and out of a total of 807 samples, 32.5% were positive for presence. The results showed a higher number of positive samples in the summer season. This was also associated with the higher concentration presence of >1000 CFU/L in the samples. Consequently, this study confirms that local hotel operators should improve their water safety and prevention plans, especially in spring and summer.
PubMed: 37754582
DOI: 10.3390/ijerph20186722