A new innovative method, MICA Legionella, allows for the automatic enumeration of Legionella pneumophila in domestic water samples in 2 days, with a detection limit of 2 CFU per test portion. Here we show that it gives equivalent results to those obtained by the French standard method NF T90-431 in 7 to 15 days.

UNASSIGNED: Antibiotics frequently induce abnormal liver function. Omadacycline is a novel aminomethylcycline antibiotic, which shows potent activity against Gram-positive and Gram-negative aerobic, anaerobic, and atypical (including Legionella pneumophila) bacteria. Of note, omadacycline is tolerable in most patients with liver impairment. However, evidence regarding the application of omadacycline in patients with Legionella pneumophila pneumonia after experiencing liver dysfunction is scarce.
UNASSIGNED: The current study reported 6 cases of patients with Legionella pneumophila pneumonia receiving omadacycline as subsequent antibiotics after experiencing liver dysfunction.
UNASSIGNED: These 6 cases were admitted to the hospital for pneumonia and received antibiotic therapy, including piperacillin-tazobactam, imipenem, meropenem, and moxifloxacin. After receiving these antibiotics, increased liver enzymes were noted. Although hepatoprotective therapy (such as magnesium isoglycyrrhizinate and glutathione) was given, the liver function was still abnormal. According to metagenomic next-generation sequencing, these patients were diagnosed with Legionella pneumophila pneumonia. Considering the abnormal liver function, the antibiotic therapy was switched to omadacycline-containing antibiotic therapy. After that, liver function was improved, and the infection was ameliorated. Ultimately, all patients discharged from the hospital, including 2 patients who achieved complete clinical symptomatic improvement and 4 patients who achieved partial clinical symptomatic improvement.
UNASSIGNED: This study emphasizes the successful treatment of switching to omadacycline after experiencing abnormal liver function in patients with Legionella pneumophila pneumonia. This study suggests that omadacycline may serve as an optional antibiotic for patients with Legionella pneumophila pneumonia, especially when occurring liver dysfunction. However, more clinical studies are required to validate our findings.

Legionnaires\' disease is an atypical pneumonia caused by Legionella pneumophila. Legionella species are found in freshwater sources and are transmitted through inhalation of contaminated aerosols. Patients commonly present with fever, chills, and cough. However, in immunosuppressed patients or severe cases, the disease can lead to multiorgan failure. In recent years, the incidence of Legionnaires\' disease has drastically increased and unfortunately is commonly underdiagnosed. Gold-standard diagnosis is made through sputum cultures; however, urine Legionella antigen remains the most common test used for diagnosis. Goal-directed care includes antibiotics and supportive care. This case highlights a rare and unique presentation of Legionnaires\' disease presenting with an elevated 2:1 aspartate aminotransferase to alanine transaminase pattern, typically seen with alcoholic hepatitis.

BACKGROUND: Legionnaires\' disease is a type of severe pneumonia caused by Legionella bacteria. The case fatality rate in this disease is 5-10%. People with various comorbidities, smokers and the elderly are at greater risk of developing the disease.
OBJECTIVE: The aim of the work is to present the results of an epidemiological investigation into the outbreak of Legionnaires\' disease that occurred in the city of Rzeszów and the surrounding area in August and September 2023 and to present the threat related to the presence of Legionella bacteria in water supply installations and networks.
METHODS: The material for this publication was data from an epidemiological investigation conducted in the outbreak of Legionnaires disease in Rzeszów in 2023.
RESULTS: Epidemiological investigation revealed 165 cases of Legionnaires\' disease in the outbreak, including 152 confirmed cases and 13 probable cases. The case fatality rate in a legionellosis outbreak was 15%. Environmental tests were carried out in residential and public buildings and industrial installations during the investigation. As part of environmental tests, 187 water samples were collected, including 87 warm water samples.
CONCLUSIONS: The outbreak of Legionnaires\' disease in the city of Rzeszów draws attention to the potential threat from the Legionella bacteria to the health and life of especially elderly people suffering from chronic diseases. The environmental tests carried out confirmed the highest number of Legionella bacteria at medium and high levels in water samples taken in the private apartments of sick people. Despite the lack of strict legal regulations clearly specifying the obligations regarding periodic disinfection of internal hot water supply installations, cooperation with their owners should be undertaken to enforce plans and actions in this area.
UNASSIGNED: Choroba legionistów jest typem ciężkiego zapalenia płuc wywołanego przez bakterie Legionella. Śmiertelność w tej chorobie wynosi 5-10%. Na większe ryzyko zachorowania narażone są osoby z różnymi chorobami współistniejącymi, osoby palące i osoby w starszym wieku.
UNASSIGNED: Celem pracy jest przedstawienie wyników dochodzenia epidemiologicznego w ognisku choroby legionistów które wystąpiło na terenie miasta Rzeszowa i okolic w sierpniu i wrześniu 2023 roku oraz przedstawienie zagrożenia związanego z obecnością bakterii Legionella w instalacjach i sieciach wodociągowych.
UNASSIGNED: Materiałem do niniejszej publikacji były dane z dochodzenia epidemiologicznego prowadzonego w ognisku choroby legionistów w Rzeszowie w 2023 roku.
UNASSIGNED: Dochodzenie epidemiologiczne ujawniło 165 przypadków choroby legionistów w ognisku, w tym 152 przypadki potwierdzone oraz 13 przypadków prawdopodobnych. Śmiertelność w ognisku legionelozy wynosiła 15%. W toku prowadzonego dochodzenia prowadzono badania środowiskowe w budynkach mieszkalnych i użyteczności publicznej oraz instalacjach przemysłowych. W ramach badań środowiskowych pobrano 187 próbek wody, w tym 87 próbek wody ciepłej.
UNASSIGNED: Ognisko choroby legionistów na terenie miasta Rzeszowa zwraca uwagę na potencjalne zagrożenie z strony bakterii Legionella dla zdrowia i życia szczególnie osób starszych cierpiących na choroby przewlekłe. Przeprowadzone badania środowiskowe potwierdziły najwyższą liczbę bakterii Legionella na poziomie średnim i wysokim w próbkach wody pobranych w mieszkaniach prywatnych osób chorych. Pomimo braku ścisłych uregulowań prawnych wskazujących wprost na obowiązki dotyczące okresowej dezynfekcji wewnętrznych instalacji zaopatrzenia w wodę ciepłą, należy podjąć współpracę z ich właścicielami w celu wyegzekwowania planów i działań w tym zakresie.

This study introduces an innovative electrochemical aptasensor designed for the highly sensitive and rapid detection of Legionella pneumophila serogroup 1 (L. pneumophila SG1), a particularly virulent strain associated with Legionellosis. Employing a rigorous selection process utilizing cell-based systematic evolution of ligands by exponential enrichment (cell-SELEX), we identified new high-affinity aptamers specifically tailored for L. pneumophila SG1. The selection process encompassed ten rounds of cell-SELEX cycles with live L. pneumophila, including multiple counter-selection steps against the closely related Legionella sub-species. The dissociation constant (Kd) of the highest affinity sequence to L. pneumophila SG1 was measured at 14.2 nM, representing a ten-fold increase in affinity in comparison with the previously reported aptamers. For the development of electrochemical aptasensor, a gold electrode was modified with the selected aptamer through the formation of self-assembled monolayers (SAMs). The newly developed aptasensor exhibited exceptional sensitivity, and specificity in detecting and differentiating various Legionella sp., with a detection limit of 5 colony forming units (CFU)/mL and an insignificant/negligible cross-reactivity with closely related sub-species. Furthermore, the aptasensor effectively detected L. pneumophila SG1 in spiked water samples, demonstrating an appreciable recovery percentage. This study shows the potential of our aptamer-based electrochemical biosensor as a promising approach for detecting L. pneumophila SG1 in diverse environments.

BACKGROUND: Legionella pneumonia is one of the most severe types of atypical pneumonia, impairing multiple organ systems, posing a threat to life. Diagnosing Legionella pneumonia is challenging due to difficulties in culturing the bacteria and limitations in immunoassay sensitivity and specificity.
METHODS: This paper reports a rare case of sepsis caused by combined infection with Legionella pneumophila and Fusobacterium necrophorum, leading to respiratory failure, acute kidney injury, acute liver injury, myocardial damage, and electrolyte disorders. In addition, we systematically reviewed literature on patients with combined Legionella infections, analyzing their clinical features, laboratory results and diagnosis.
CONCLUSIONS: For pathogens that require prolonged incubation periods and are less sensitive to conventional culturing methods, metagenomic next-generation sequencing (mNGS) can be a powerful supplement to pathogen screening and plays a significant role in the auxiliary diagnosis of complex infectious diseases.

Bacterial adhesion is a fundamental process which enables colonisation of niche environments and is key for infection. However, in Legionella pneumophila, the causative agent of Legionnaires\' disease, these processes are not well understood. The Legionella collagen-like protein (Lcl) is an extracellular peripheral membrane protein that recognises sulphated glycosaminoglycans 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 trimer arrangement with a positively charged external surface and negatively charged solvent exposed internal cavity. Through molecular dynamics simulations, we show how the glycosaminoglycan chondroitin-4-sulphate associates with the Lcl-CTD surface via distinct 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.

Through immune memory, infections have a lasting effect on the host. While memory cells enable accelerated and enhanced responses upon rechallenge with the same pathogen, their impact on susceptibility to unrelated diseases is unclear. We identify a subset of memory T helper 1 (Th1) cells termed innate acting memory T (TIA) cells that originate from a viral infection and produce IFN-γ with innate kinetics upon heterologous challenge in vivo. Activation of memory TIA cells is induced in response to IL-12 in combination with IL-18 or IL-33 but is TCR independent. Rapid IFN-γ production by memory TIA cells is protective in subsequent heterologous challenge with the bacterial pathogen Legionella pneumophila. In contrast, antigen-independent reactivation of CD4+ memory TIA cells accelerates disease onset in an autoimmune model of multiple sclerosis. Our findings demonstrate that memory Th1 cells can acquire additional TCR-independent functionality to mount rapid, innate-like responses that modulate susceptibility to heterologous challenges.

Protein ubiquitination is one of the most important posttranslational modifications (PTMs) in eukaryotes and is involved in the regulation of almost all cellular signaling pathways. The intracellular bacterial pathogen Legionella pneumophila translocates at least 26 effectors to hijack host ubiquitination signaling via distinct mechanisms. Among these effectors, SidC/SdcA are novel E3 ubiquitin ligases with the adoption of a Cys-His-Asp catalytic triad. SidC/SdcA are critical for the recruitment of endoplasmic reticulum (ER)-derived vesicles to the Legionella-containing vacuole (LCV). However, the ubiquitination targets of SidC/SdcA are largely unknown, which restricts our understanding of the mechanisms used by these effectors to hijack the vesicle trafficking pathway. Here, we demonstrated that multiple Rab small GTPases and target soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) proteins are bona fide ubiquitination substrates of SidC/SdcA. SidC/SdcA-mediated ubiquitination of syntaxin 3 and syntaxin 4 promotes their unconventional pairing with the vesicle-SNARE protein Sec22b, thereby contributing to the membrane fusion of ER-derived vesicles with the phagosome. In addition, our data reveal that ubiquitination of Rab7 by SidC/SdcA is critical for its association with the LCV membrane. Rab7 ubiquitination could impair its binding with the downstream effector Rab-interacting lysosomal protein (RILP), which partially explains why LCVs avoid fusion with lysosomes despite the acquisition of Rab7. Taken together, our study reveals the biological mechanisms employed by SidC/SdcA to promote the maturation of the LCVs.

Legionella, one of the main pathogens that causes community-acquired pneumonia, can lead to Legionella pneumonia, a condition characterized predominantly by severe pneumonia. This disease, caused by the bacterium Legionella pneumophila, can quickly progress to critical pneumonia and is often associated with damage to multiple organs. As a result, it requires close attention in terms of clinical diagnosis and treatment. Omadacycline, a new type of tetracycline derivative belonging to the aminomethylcycline class of antibiotics, is a semi-synthetic compound derived from minocycline. Its key structural feature, the aminomethyl modification, allows omadacycline to overcome bacterial resistance and broadens its range of effectiveness against bacteria. Clinical studies have demonstrated that omadacycline is not metabolized in the body, and patients with hepatic and renal dysfunction do not need to adjust their dosage. This paper reports a case of successful treatment of Legionella pneumonia with omadacycline in a patient who initially did not respond to empirical treatment with moxifloxacin. The patient also experienced electrolyte disturbance, as well as dysfunction in the liver and kidneys, delirium, and other related psychiatric symptoms.