-
ELife Jun 2019Communities of bacteria that cause Legionnaires' disease repel other bacteria by secreting an acid called HGA.
Communities of bacteria that cause Legionnaires' disease repel other bacteria by secreting an acid called HGA.
Topics: Environmental Microbiology; Humans; Legionella pneumophila; Legionnaires' Disease; Phenylalanine; Tyrosine
PubMed: 31251173
DOI: 10.7554/eLife.48695 -
Frontiers in Cellular and Infection... 2017Protein ubiquitination is critical for regulation of numerous eukaryotic cellular processes such as protein homeostasis, cell cycle progression, immune response, DNA... (Review)
Review
Protein ubiquitination is critical for regulation of numerous eukaryotic cellular processes such as protein homeostasis, cell cycle progression, immune response, DNA repair, and vesicular trafficking. Ubiquitination often leads to the alteration of protein stability, subcellular localization, or interaction with other proteins. Given the importance of ubiquitination in the regulation of host immunity, it is not surprising that many infectious agents have evolved strategies to interfere with the ubiquitination network with sophisticated mechanisms such as functional mimicry. The facultative intracellular pathogen is the causative agent of Legionnaires' disease. is phagocytosed by macrophages and is able to replicate within a niche called Legionella-containing vacuole (LCV). The biogenesis of LCV is dependent upon the Dot/Icm type IV secretion system which delivers more than 330 effector proteins into host cytosol. The optimal intracellular replication of requires the host ubiquitin-proteasome system. Furthermore, membranes of the bacterial phagosome are enriched with ubiquitinated proteins in a way that requires its Dot/Icm type IV secretion system, suggesting the involvement of effectors in the manipulation of the host ubiquitination machinery. Here we summarize recent advances in our understanding of mechanisms exploited by effector proteins to hijack the host ubiquitination pathway.
Topics: Gene Expression Regulation; Host-Pathogen Interactions; Humans; Immune Evasion; Legionella pneumophila; Legionnaires' Disease; Type IV Secretion Systems; Ubiquitin; Ubiquitination
PubMed: 29376029
DOI: 10.3389/fcimb.2017.00487 -
Applied and Environmental Microbiology Mar 2022species are facultative intracellular pathogens that cause a life-threatening pneumonia termed Legionnaires' disease. Legionella pneumophila employs the Lqs-LvbR (...
species are facultative intracellular pathogens that cause a life-threatening pneumonia termed Legionnaires' disease. Legionella pneumophila employs the Lqs-LvbR ( quorum sensing- virulence and biofilm regulator) network to regulate virulence and motility, but its role for growth in media is ill-defined. Here, we report that compared to the L. pneumophila reference strain JR32, a Δ mutant showed a reduced lag phase at 30°C and reached a higher cell density at 45°C, while the Δ, Δ, and Δ mutants showed a longer lag phase and reached a lower cell density. A Δ mutant resumed growth like the parental strain at 30°C but exhibited a substantially reduced cell density at 45°C. Thus, LvbR is an important cell density regulator at elevated temperatures. Environmental and clinical L. pneumophila strains grew in -(2-acetamido)-2-aminoethanesulfonic acid (ACES)-buffered yeast extract (AYE) medium after distinct lag phases with similar rates at 30°C, reached different cell densities at the optimal growth temperature of 40°C, and no longer grew at 50°C. Legionella longbeachae reached a rather low cell density at 40°C and did not grow at and beyond 45°C. Genes encoding components of the Lqs-LvbR network were present in the genomes of the environmental and clinical L. pneumophila isolates, and upon growth at 30°C or 45°C, the P, P, P, and P promoters from strain JR32 were expressed in these strains with distinct patterns. Taken together, our results indicate that the Lqs-LvbR network governs the temperature-dependent growth onset and cell density of the L. pneumophila reference strain JR32 and possibly also of environmental and clinical L. pneumophila isolates. Environmental bacteria of the genus are the causative agents of the severe pneumonia Legionnaires' disease, the incidence of which is on the rise worldwide. Legionella pneumophila and Legionella longbeachae are the clinically most relevant species. The opportunistic pathogens are inhaled through contaminated aerosols and replicate in human lung macrophages with a mechanism similar to that in their natural hosts, free-living amoebae. Given their prevalence in natural and technical water systems, an efficient control of spp. by physical, chemical, or biological means will reduce the incidence of Legionnaires' disease. Here, we show that the quorum sensing (Lqs) system and the pleiotropic transcription factor LvbR govern the temperature-dependent growth onset and cell density of bacterial cultures. Hence, the growth of L. pneumophila in water systems is determined not only by the temperature and nutrient availability but also by quorum sensing, i.e., density- and signaling molecule-dependent gene regulation.
Topics: Bacterial Proteins; Cell Count; Humans; Legionella; Legionella pneumophila; Legionnaires' Disease; Quorum Sensing; Temperature
PubMed: 34985976
DOI: 10.1128/aem.02370-21 -
BMJ Case Reports Jun 2019Legionnaires' disease is a recognised but rare cause of rhabdomyolysis. It can be further complicated with renal impairment. In this case report, we describe a...
Legionnaires' disease is a recognised but rare cause of rhabdomyolysis. It can be further complicated with renal impairment. In this case report, we describe a previously healthy, semiactive 50-year-old man who within days was reduced to having periods of dyspnea after minutes of walking in addition to near fatal acute renal failure. He was found to have the rare triad of pneumonia, renal failure and rhabdomyolysis, which is associated with high morbidity and mortality. He was treated according to guidelines with azithromycin monotherapy and aggressive fluid hydration. 20 days after admission, the patient was walking independently and discharged home.
Topics: Acute Kidney Injury; Anti-Bacterial Agents; Azithromycin; Diagnosis, Differential; Humans; Legionella pneumophila; Legionnaires' Disease; Male; Middle Aged; Pneumonia; Rhabdomyolysis; Treatment Outcome
PubMed: 31227570
DOI: 10.1136/bcr-2019-229243 -
Frontiers in Cellular and Infection... 2019Approximately 85% of cases of Legionnaires' disease are caused by serogroup 1. In this study, we analyzed the distribution of alleles, and genes of...
Approximately 85% of cases of Legionnaires' disease are caused by serogroup 1. In this study, we analyzed the distribution of alleles, and genes of lipopolysaccharide (LPS) and sequence-based types of 616 serogroup 1 strains isolated in Japan (206 clinical, 225 environmental) and China (13 clinical and 172 environmental). The gene was harbored by significantly more of the clinical isolates compared with the environmental isolates (90.3 vs. 19.1% and 61.6 vs. 3.0%, respectively; both < 0.001). genes were detected in 51.0% of Japanese clinical and 36.0% of Japanese environmental ( = 0.001) isolates, as well as 15.3% of Chinese clinical and 9.9% of Chinese environmental isolates ( = 0.544). genes were detected in 12.1% of Japanese clinical and 5.8% of Japanese environmental ( = 0.017) isolates, as well as 7.7% of Chinese clinical and 3.4% of Chinese environmental isolates ( = 0.388). The Japanese and Chinese isolates were assigned to 203 and 36 different sequence-types (ST), respectively. ST1 was predominant. Most isolates with the same ST also had the same , and gene subgroups. In conclusion, the was present in most of the clinical isolates, but was absent from most of the environmental isolates from both China and Japan, regardless of the water source and SBT type. PCR-based serotyping and subgrouping methods can be used to define a hierarchy of virulence genotypes that require stringent surveillance to prevent human disease.
Topics: Acetyltransferases; Alleles; Bacterial Proteins; China; Environmental Microbiology; Genes, Bacterial; Genetic Variation; Genotype; Humans; Japan; Legionella pneumophila; Legionnaires' Disease; Lipopolysaccharides; Molecular Typing; Serogroup; Virulence Factors
PubMed: 31448241
DOI: 10.3389/fcimb.2019.00274 -
Przeglad Epidemiologiczny 2017The aim of the study was to assess the epidemiological situation of legionellosis in Poland in 2015 in comparison to the preceding years.
OBJECTIVE
The aim of the study was to assess the epidemiological situation of legionellosis in Poland in 2015 in comparison to the preceding years.
MATERIAL AND METHODS
We reviewed data published in the annual bulletin: “Infectious diseases and poisonings in Poland in 2015” and its prior versions along with the legionellosis case reports sent from Sanitary- Epidemiological Stations to the Department of Epidemiology of NIPH - NIH.
RESULTS
In Poland, both two forms of legionellosis - Legionnaires’ disease (a severe form of disease accompanied by pneumonia) and Pontiac fever (mild, influenza-like form of infection) - are notifiable. In 2015, a total of 23 cases of Legionnaires’ disease have been reported (there were no reports of Pontiac fever). The annual incidence rate 0.060 (per 100,000 population) slightly increased when compared to previous year as well as to the median (incidence) for 2009-2013. The infections were reported in 10 provinces, including five, which in previous years usually did not register any cases; however, there is a number of provinces that did not identify any LD cases in recent years. The incidence in males (0.097 per 100,000) was almost 4-times higher compared to females (0.025). Except for one cluster of two, all cases were sporadic; All patients required hospitalization. The Sanitary Inspection reported four fatal cases – all men 43- 67 years/old. Eighteen cases were likely acquired in the country, including a cluster of two cases linked with contaminated building water system. Four cases were associated with travels abroad (to Russia, Croatia, United Arab Emirates and USA) and in one case the exposure occurred during the transport of goods (lorry driver).
SUMMARY AND CONCLUSIONS
This study suggests, that legionellosis is likely under recognized and under diagnosed in all provinces of the country. Geographical variations in incidence may reflect local differences in availability of laboratory tests for LD. Number of detected cases - without information on the number of laboratory tests performed - do not appear to be sufficient to fully assess the epidemiological situation.
PubMed: 29181967
DOI: No ID Found -
Diagnostic Microbiology and Infectious... Feb 2018Legionella pneumophila is responsible for Legionnaires' disease (LD). Its detection in both environmental and clinical samples is mainly performed by culture plate...
Legionella pneumophila is responsible for Legionnaires' disease (LD). Its detection in both environmental and clinical samples is mainly performed by culture plate method which requires up to 10days to obtain results. Nowadays, there are commercial antibodies against this bacterium, but they have not been tested against all subgroups of L. pneumophila sg 1 or serogroups 1-16 or their cross-reactions with other non-Legionella bacteria. Indeed, many of these antibodies became available when only 8 serogroups of L. pneumophila had been described. We tested 7 antibodies and found that 2 (Mab 8/5 and OBT) specifically detected all the subgroups of L. pneumophila sg 1, one without cross-reactions (Mab8/5). Moreover, the LP3IIG2 antibody detected almost all serogroups tested with lower rates of cross-reactivity, resulting in a specific sensitive antibody for the detection of L. pneumophila. LP3IIG2 presented higher rate of cross-reactivity against respiratory non-Legionella isolates, thereby contraindicating its clinical applicability.
Topics: Antibodies, Bacterial; Antigens, Bacterial; Bacterial Typing Techniques; Environmental Microbiology; Fluorescent Antibody Technique, Indirect; Humans; Legionella pneumophila; Legionnaires' Disease; Serotyping
PubMed: 29217420
DOI: 10.1016/j.diagmicrobio.2017.11.005 -
Frontiers in Cellular and Infection... 2020Autophagy is a fundamental and highly conserved eukaryotic process, responsible for maintaining cellular homeostasis and releasing nutrients during times of starvation.... (Review)
Review
Autophagy is a fundamental and highly conserved eukaryotic process, responsible for maintaining cellular homeostasis and releasing nutrients during times of starvation. An increasingly important function of autophagy is its role in the cell autonomous immune response; a process known as xenophagy. Intracellular pathogens are engulfed by autophagosomes and targeted to lysosomes to eliminate the threat to the host cell. To counteract this, many intracellular bacterial pathogens have developed unique approaches to overcome, evade, or co-opt host autophagy to facilitate a successful infection. The intracellular bacteria and are able to avoid destruction by the cell, causing Legionnaires' disease and Q fever, respectively. Despite being related and employing homologous Dot/Icm type 4 secretion systems (T4SS) to translocate effector proteins into the host cell, these pathogens have developed their own unique intracellular niches. evades the host endocytic pathway and instead forms an ER-derived vacuole, while requires delivery to mature, acidified endosomes which it remodels into a large, replicative vacuole. Throughout infection, effectors act at multiple points to inhibit recognition by xenophagy receptors and disrupt host autophagy, ensuring it avoids fusion with destructive lysosomes. In contrast, employs its effector cohort to control autophagy, hypothesized to facilitate the delivery of nutrients and membrane to support the growing vacuole and replicating bacteria. In this review we explore the effector proteins that these two organisms utilize to modulate the host autophagy pathway in order to survive and replicate. By better understanding how these pathogens manipulate this highly conserved pathway, we can not only develop better treatments for these important human diseases, but also better understand and control autophagy in the context of human health and disease.
Topics: Autophagy; Bacterial Proteins; Coxiella burnetii; Host-Pathogen Interactions; Humans; Legionella pneumophila; Legionnaires' Disease; Vacuoles
PubMed: 33251162
DOI: 10.3389/fcimb.2020.599762 -
Microbes and Infection Dec 2014Innate immune receptors evolved to sense conserved molecules that are present in microbes or are released during non-physiological conditions. Activation of these... (Review)
Review
Innate immune receptors evolved to sense conserved molecules that are present in microbes or are released during non-physiological conditions. Activation of these receptors is essential for early restriction of microbial infections and generation of adaptive immunity. Among the conserved molecules sensed by innate immune receptors are the nucleic acids, which are abundantly contained in all infectious organisms including virus, bacteria, fungi and parasites. In this review we focus in the innate immune proteins that function to sense nucleic acids from the intracellular bacterial pathogen Legionella pneumophila and the importance of these processes to the outcome of the infection.
Topics: Animals; DNA, Bacterial; Host-Pathogen Interactions; Humans; Immunity, Innate; Inflammasomes; Interferon Type I; Legionella pneumophila; Legionnaires' Disease; Nucleic Acids; Receptors, Immunologic; Toll-Like Receptor 9; Toll-Like Receptors
PubMed: 25172398
DOI: 10.1016/j.micinf.2014.08.008 -
Antimicrobial Agents and Chemotherapy Dec 2019
Topics: Azithromycin; China; Drug Resistance, Microbial; Humans; Legionella pneumophila; Legionnaires' Disease; Serogroup
PubMed: 31862771
DOI: 10.1128/AAC.01986-19