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1.
Zhonghua Yu Fang Yi Xue Za Zhi ; 55(1): 72-77, 2021 Jan 06.
Artigo em Chinês | MEDLINE | ID: mdl-33455135

RESUMO

Objective: To understand the epidemiological and pathogenic characteristics of Legionella in artificial water environment of public places in Shanghai from 2011 to 2018, and to provide scientific basis for the prevention and control of Legionellosis. Methods: A total of 4 817 samples of artificial water environment were collected from 31 public places in Huangpu, Jing'an, Xuhui and Songjiang districts of Shanghai from 2011 to 2108. Epidemiological characteristics of the collected years and months, regional and site types, and sample types were analyzed. After treatment, culture and isolation of the collected water samples, the positive samples were analyzed for Legionella typing characteristics. Results: The positive rate of Legionella pneumophila was 21.57% (1 039/4 817), of which 96.25% (1 000/1 039) was single type, 84.31% (876/1 039) was Legionella pneumophila type 1, followed by Legionella pneumophila type 7 and 6, which accounted for 4.72% (49/1 039) and 3.75% (39/1 039), respectively, and 29 (29/1 039) were multi-type positive. Further typing. From May to October, the highest positive rates were found in July and August, 27.61%(222/804)and 28.61% (230/804)respectively. There were significant differences between different months (P<0.001); the highest positive rates were found in central air-conditioning cooling water and chilled water (32.40%) and there were significant differences among different water samples (P<0.001). Legionella pneumophila type 1, type 7 and type 6 were the main diversity distribution characteristics in artificial water environment of different regions, different time, different places and different types of public places. Legionella pneumophila type 1 accounted for the highest proportion, and the proportion of positive samples under different epidemiological characteristics was more than 71.64%. Conclusion: There is relatively serious pollution of Legionella pneumophila type 1 in the artificial water environment of public places in Shanghai. It is necessary to strengthen the disinfection of cooling water/freezing water of central air conditioning in public places in July and August every year.


Assuntos
Legionella pneumophila , Legionella , China , Humanos , Água , Microbiologia da Água
2.
Nat Commun ; 12(1): 460, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33469029

RESUMO

Legionella pneumophila infects eukaryotic cells by forming a replicative organelle - the Legionella containing vacuole. During this process, the bacterial protein DrrA/SidM is secreted and manipulates the activity and post-translational modification (PTM) states of the vesicular trafficking regulator Rab1. As a result, Rab1 is modified with an adenosine monophosphate (AMP), and this process is referred to as AMPylation. Here, we use a chemical approach to stabilise low-affinity Rab:DrrA complexes in a site-specific manner to gain insight into the molecular basis of the interaction between the Rab protein and the AMPylation domain of DrrA. The crystal structure of the Rab:DrrA complex reveals a previously unknown non-conventional Rab-binding site (NC-RBS). Biochemical characterisation demonstrates allosteric stimulation of the AMPylation activity of DrrA via Rab binding to the NC-RBS. We speculate that allosteric control of DrrA could in principle prevent random and potentially cytotoxic AMPylation in the host, thereby perhaps ensuring efficient infection by Legionella.


Assuntos
Monofosfato de Adenosina/metabolismo , Proteínas de Bactérias/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Legionella pneumophila/patogenicidade , Doença dos Legionários/patologia , Proteínas rab1 de Ligação ao GTP/metabolismo , Regulação Alostérica , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/ultraestrutura , Sítios de Ligação/genética , Cristalografia por Raios X , Fatores de Troca do Nucleotídeo Guanina/genética , Fatores de Troca do Nucleotídeo Guanina/isolamento & purificação , Fatores de Troca do Nucleotídeo Guanina/ultraestrutura , Guanosina Trifosfato/metabolismo , Humanos , Legionella pneumophila/metabolismo , Doença dos Legionários/microbiologia , Macrófagos Alveolares/metabolismo , Macrófagos Alveolares/microbiologia , Fagocitose , Ligação Proteica , Processamento de Proteína Pós-Traducional , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , Proteínas rab1 de Ligação ao GTP/genética , Proteínas rab1 de Ligação ao GTP/isolamento & purificação , Proteínas rab1 de Ligação ao GTP/ultraestrutura
3.
Water Res ; 190: 116743, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33352528

RESUMO

A predictive mathematical model describing the effect of temperature on the inactivation of Legionella pneumophila in water was developed. Thermal inactivation of L. pneumophila was monitored under isothermal conditions (51 - 61°C). A primary log-linear model was fitted to the inactivation data and the estimated D values ranged from 0.23 to 25.31 min for water temperatures from 61 to 51°C, respectively. The effect of temperature on L. pneumophila inactivation was described using a secondary model, and the model parameters z value and Dref (D-value at 55°C) were estimated at 5.54°C and 3.47 min, respectively. The developed model was further validated under dynamic temperature conditions mimicking various conditions of water thermal disinfection in plumbing systems. The results indicated that the model can satisfactorily predict thermal inactivation of the pathogen at dynamic temperature environments and effectively translate water temperature profiles to cell number reduction. The application of the model in combination with effective temperature monitoring could provide the basis of an integrated preventive approach for the effective control of L. pneumophila in plumbing systems.


Assuntos
Legionella pneumophila , Legionella , Desinfecção , Engenharia Sanitária , Temperatura , Água , Microbiologia da Água , Abastecimento de Água
4.
Cell Host Microbe ; 28(5): 634-636, 2020 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-33181075

RESUMO

In this issue of Cell Host & Microbe, Liu et al. elucidates how Legionella-infected macrophages use the alveolar epithelium to metabolically process myeloid cells and advance antibacterial inflammation. This highlights the alveolar epithelium's importance as a key signaling bridge and could yield a metabolism-based blueprint for hampering Legionnaires' disease.


Assuntos
Legionella pneumophila , Legionella , Doença dos Legionários , Antibacterianos , Comunicação Celular , Humanos , Inflamação , Macrófagos
5.
Medicine (Baltimore) ; 99(43): e22812, 2020 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33120803

RESUMO

INTRODUCTION: Legionnaires' disease is caused by Legionella bacteria, and commonly manifests as pneumonia and has a high fatality rate. PATIENT CONCERNS: This case study reports on the fatal incident of a patient, initially diagnosed with pneumonia, and subsequently diagnosed with Legionnaires' disease caused by a new sequence type (ST) of Legionella. DIAGNOSIS: It is speculated that the patient acquired Legionnaires' disease from a contaminated water source. Legionnaires' disease was diagnosed using the Legionella urinary antigen assay and bacterial cultures of respiratory secretions; Legionella pneumophilia Type 1 was also identified through serological testing. Sequence-based typing of the cultured bacterium revealed it to be a previously unidentified species, and it was named ST2345 new-type. INTERVENTIONS: In addition to the treatment of Legionnaires' disease, blood samples taken on the second day of admission showed a co-infection of Candida tropicalis, which was treated with anti-fungal treatment. The patient improved after a week, however, on the seventh day of administration lower respiratory secretions showed the growth of Klebsiella pneumonia, indicative of ventilator-associated pneumonia. OUTCOMES: Despite active treatment, the patient passed away due to multiple organ failure. As this was a fatal case, further research is needed to determine whether the critical condition of this case was related to the virulence of the novel Legionella strain. CONCLUSION: A key finding of this study is that treatment for suspected Legionnaires' disease must be administered rapidly, as infection with Legionella may give rise to secondary pathogenic infections.


Assuntos
Legionella pneumophila/genética , Doença dos Legionários/complicações , Insuficiência de Múltiplos Órgãos/etiologia , Humanos , Doença dos Legionários/terapia , Masculino , Pessoa de Meia-Idade , Sorogrupo
6.
PLoS One ; 15(8): e0238479, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32866217

RESUMO

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.


Assuntos
Antígenos de Bactérias/metabolismo , Antígenos de Bactérias/urina , Bioensaio/métodos , Líquido Cefalorraquidiano/microbiologia , Legionella pneumophila/isolamento & purificação , Streptococcus pneumoniae/isolamento & purificação , Urina/microbiologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Testes Imunológicos/métodos , Lactente , Doença dos Legionários/metabolismo , Doença dos Legionários/microbiologia , Doença dos Legionários/urina , Masculino , Meningite/metabolismo , Meningite/microbiologia , Meningite/urina , Pneumonia Pneumocócica/metabolismo , Pneumonia Pneumocócica/microbiologia , Pneumonia Pneumocócica/urina , Sensibilidade e Especificidade , Sorogrupo , Adulto Jovem
7.
Environ Res ; 191: 110231, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32976823

RESUMO

The COVID-19 pandemic started in China in early December 2019, and quickly spread around the world. The epidemic gradually started in Italy at the end of February 2020, and by May 31, 2020, 232,664 cases and 33,340 deaths were confirmed. As a result of this pandemic, the Italian Ministerial Decree issued on March 11, 2020, enforced lockdown; therefore, many social, recreational, and cultural centers remained closed for months. In Apulia (southern Italy), all non-urgent hospital activities were suspended, and some wards were closed, with a consequent reduction in the use of the water network and the formation of stagnant water. This situation could enhance the risk of exposure of people to waterborne diseases, including legionellosis. The purpose of this study was to monitor the microbiological quality of the water network (coliforms, E. coli, Enterococci, P. aeruginosa, and Legionella) in three wards (A, B and C) of a large COVID-19 regional hospital, closed for three months due to the COVID-19 emergency. Our study revealed that all three wards' water network showed higher contamination by Legionella pneumophila sg 1 and sg 6 at T1 (after lockdown) compared to the period before the lockdown (T0). In particular, ward A at T1 showed a median value = 5600 CFU/L (range 0-91,000 CFU/L) vs T0, median value = 75 CFU/L (range 0-5000 CFU/L) (p-value = 0.014); ward B at T1 showed a median value = 200 CFU/L (range 0-4200 CFU/L) vs T0, median value = 0 CFU/L (range 0-300 CFU/L) (p-value = 0.016) and ward C at T1 showed a median value = 175 CFU/L (range 0-22,000 CFU/L) vs T0, median value = 0 CFU/L (range 0-340 CFU/L) (p-value < 0.001). In addition, a statistically significant difference was detected in ward B between the number of positive water samples at T0 vs T1 for L. pneumophila sg 1 and sg 6 (24% vs 80% p-value < 0.001) and for coliforms (0% vs 64% p-value < 0.001). Moreover, a median value of coliform load resulted 3 CFU/100 ml (range 0-14 CFU/100 ml) at T1, showing a statistically significant increase versus T0 (0 CFU/100 ml) (p-value < 0.001). Our results highlight the need to implement a water safety plan that includes staff training and a more rigorous environmental microbiological surveillance in all hospitals before occupying a closed ward for a longer than one week, according to national and international guidelines.


Assuntos
Infecções por Coronavirus , Legionella pneumophila , Pandemias , Pneumonia Viral , Betacoronavirus , China/epidemiologia , Escherichia coli , Humanos , Itália/epidemiologia , Água , Microbiologia da Água , Abastecimento de Água
8.
Euro Surveill ; 25(30)2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32734857

RESUMO

We report a case of Legionella pneumonia in a dishwasher of a restaurant in Rome, Italy, just after the end of the lockdown that was in place to control the SARS-CoV-2 epidemic. The case highlights the importance of strict monitoring of water and air systems immediately before reopening business or public sector buildings, and the need to consider Legionella infections among the differential diagnosis of respiratory infections after lockdown due to the ongoing COVID-19 pandemic.


Assuntos
Antígenos de Bactérias/urina , Legionella pneumophila/isolamento & purificação , Legionella/isolamento & purificação , Doença dos Legionários/diagnóstico , Levofloxacino/uso terapêutico , Pneumonia/diagnóstico , Administração Intravenosa , Adulto , Anti-Infecciosos Urinários/uso terapêutico , Tosse/etiologia , Febre/etiologia , Cefaleia/etiologia , Humanos , Doença dos Legionários/tratamento farmacológico , Doença dos Legionários/urina , Masculino , Pneumonia/tratamento farmacológico , Pneumonia/urina , Resultado do Tratamento
9.
PLoS Pathog ; 16(8): e1008734, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32853279

RESUMO

AMPylation, the post-translational modification with adenosine monophosphate (AMP), is catalyzed by effector proteins from a variety of pathogens. Legionella pneumophila is thus far the only known pathogen that, in addition to encoding an AMPylase (SidM/DrrA), also encodes a deAMPylase, called SidD, that reverses SidM-mediated AMPylation of the vesicle transport GTPase Rab1. DeAMPylation is catalyzed by the N-terminal phosphatase-like domain of SidD. Here, we determined the crystal structure of full length SidD including the uncharacterized C-terminal domain (CTD). A flexible loop rich in aromatic residues within the CTD was required to target SidD to model membranes in vitro and to the Golgi apparatus within mammalian cells. Deletion of the loop (Δloop) or substitution of its aromatic phenylalanine residues rendered SidD cytosolic, showing that the hydrophobic loop is the primary membrane-targeting determinant of SidD. Notably, deletion of the two terminal alpha helices resulted in a CTD variant incapable of discriminating between membranes of different composition. Moreover, a L. pneumophila strain producing SidDΔloop phenocopied a L. pneumophila ΔsidD strain during growth in mouse macrophages and displayed prolonged co-localization of AMPylated Rab1 with LCVs, thus revealing that membrane targeting of SidD via its CTD is a critical prerequisite for its ability to catalyze Rab1 deAMPylation during L. pneumophila infection.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Membrana Celular/microbiologia , Legionella pneumophila/enzimologia , Doença dos Legionários/microbiologia , Monofosfato de Adenosina/metabolismo , Animais , Proteínas de Bactérias/genética , Feminino , Complexo de Golgi/metabolismo , Humanos , Legionella pneumophila/química , Legionella pneumophila/genética , Camundongos , Domínios Proteicos
12.
Artigo em Inglês | MEDLINE | ID: mdl-32796666

RESUMO

The current systematic review investigates the antibiotic susceptibility pattern of Legionella pneumophila isolates from the 1980s to the present day, deriving data from clinical and/or water samples from studies carried out all over the world. Eighty-nine papers meeting the inclusion criteria, i.e., "Legionella pneumophila" and "resistance to antibiotics", were evaluated according to pre-defined validity criteria. Sixty articles referred to clinical isolates, and 18 articles reported water-related L. pneumophila isolates, while 11 articles included both clinical and water isolates. Several methods have been proposed as suitable for the determination of MICs, such as the E-test, broth and agar dilution, and disk diffusion methods, in vivo and in vitro, using various media. The E-test method proposed by the European Society of Clinical Microbiology and Infectious Diseases (EUCAST) seems to be the second most frequently used method overall, but it is the preferred method in the most recent publications (2000-2019) for the interpretation criteria. Erythromycin has been proved to be the preference for resistance testing over the years. However, in the last 19 years, the antibiotics ciprofloxacin (CIP), erythromycin (ERM), levofloxacin (LEV) and azithromycin (AZM) were the ones that saw an increase in their use. A decrease in the sensitivity to antibiotics was identified in approximately half of the reviewed articles.


Assuntos
Antibacterianos/farmacologia , Legionella pneumophila/efeitos dos fármacos , Doença dos Legionários/tratamento farmacológico , Antibacterianos/uso terapêutico , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Eritromicina , Humanos , Legionella pneumophila/isolamento & purificação , Doença dos Legionários/diagnóstico , Testes de Sensibilidade Microbiana
13.
Zhonghua Jie He He Hu Xi Za Zhi ; 43(7): 557-563, 2020 Jul 12.
Artigo em Chinês | MEDLINE | ID: mdl-32629554

RESUMO

Objective: To describe the clinical characteristics and treatment of severe community-acquired pneumonia(SCAP) caused by Legionella pneumophila with acute respiratory failure and to analyze the risk factors for mortality. Methods: From October 2011 to October 2019, 34 patients were diagnosed with SCAP caused by Legionella pneumophila with acute respiratory failure.There were 25 males and 9 females, aged from 17 to 82 years, with a median age of 61 (48, 69) years. According to the prognosis, the patients were divided into a survival group and a death group for comparative analysis.The survival group included 24 patients, 17 males and 7 females, with a median age of 65 (55, 70) years. There were 10 cases in the death group, 8 males and 2 females, with a median age of 53 (50, 58) years. Multivariable logistic regression analysis was used for risk factors of ICU mortality. Results: The median time of admission to ICU was 7 (5, 11) days, the median time of stay in RICU was 12 (7, 22) days, and the PaO(2)/FiO(2) was 134 (91, 216) mmHg(1 mmHg=0.133 kPa). Ten patients died during ICU hospitalization, with a mortality of 29%. Sequential organ failure assessment (SOFA) of death group was 9 (7, 12), which was significantly higher than that of the survival group [4 (3, 8)], P=0.018. The time from onset of pneumonia symptoms to initiation of targeted treatment of the death group was 10 (7, 14) d, which was significantly longer than that of the survival group of [4 (3, 7) d], P=0.019. Multivariable logistic regression analysis showed that SOFA score (OR=1.461, 95%CI 1.041-2.051, P=0.028) and the time from onset of pneumonia symptoms to initiation of targeted treatment (OR=1.293, 95%CI 1.029-1.625, P=0.027) were independent risk factors for hospital mortality. Conclusions: The ICU mortality of severe legionella pneumonia was high. Critical organ dysfunctions and delayed initial targeted treatment were related with the increase of ICU mortality.


Assuntos
Infecções Comunitárias Adquiridas/diagnóstico , Legionella pneumophila/isolamento & purificação , Doença dos Legionários/diagnóstico , Pneumonia Bacteriana/diagnóstico , Insuficiência Respiratória , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Infecções Comunitárias Adquiridas/microbiologia , Infecções Comunitárias Adquiridas/mortalidade , Infecções Comunitárias Adquiridas/terapia , Feminino , Humanos , Unidades de Terapia Intensiva , Doença dos Legionários/mortalidade , Doença dos Legionários/terapia , Masculino , Pessoa de Meia-Idade , Pneumonia Bacteriana/mortalidade , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida , Adulto Jovem
14.
Water Res ; 183: 115951, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32673893

RESUMO

The information about the impact of copper pipes on the growth of Legionella pneumophila in premise plumbing is controversial. For this reason, pipe segments of copper, stainless steel (SS), mild steel (MS), polyethylene, chlorinated polyvinylchloride (CPVC) and glass (controls) were exposed to intermittently flowing (20 min stagnation time) nonchlorinated tap water of 37 °C or 16 °C (ambient temperature) during six months to study the impact of metals on biofilm formation and growth of L. pneumophila. Biofilm concentrations (BfC, measured as ATP) on copper were 3 (at 37 °C) to 6 (at 16 °C) times higher than on SS. The maximum colony counts of L. pneumophila on the materials tested at 37 °C showed a quadratic relationship with the associated BfCs, with highest values on copper and MS. The average Cu concentration on the glass control of copper (glass-copper) was more than two log units lower than the Fe concentration on glass-MS, suggesting that copper released less corrosion by-products than MS. The release of corrosion by-products with attached biomass from MS most likely enhanced biofilm formation on glass-MS. Cloning and 16S RNA gene sequence analysis of the predominating biofilm bacteria revealed that an uncultured Xanthobacteraceae bacterium and Reyranella accounted for 75% of the bacterial community on copper at 37 °C. The nitrite-oxidizing Nitrospira moscoviensis, which can also utilize hydrogen (H2) and formate, accounted for >50% of the bacterial abundance in the biofilms on MS and glass-MS at 37 °C. The predominating presence of the strictly anaerobic non-fermentative Fe(III)-reducing Geobacter and the Fe(II)-oxidizing Gallionella on MS exposed to tap water of 16 °C indicated anoxic niches and the availability of H2, low molecular weight carboxylic acids (LMWCAs) and Fe(II) at the MS surface. LMWCAs likely also promoted bacterial growth on copper, but the release mechanisms from natural organic matter at the surface of corroding metals are unclear. The effects of water stagnation time and flow dynamics on biofilm formation on copper requires further investigation.


Assuntos
Legionella pneumophila , Bactérias , Biofilmes , Cobre , Compostos Férricos , Aço , Microbiologia da Água , Abastecimento de Água
15.
Praxis (Bern 1994) ; 109(8): 658-664, 2020.
Artigo em Alemão | MEDLINE | ID: mdl-32517597

RESUMO

CME: Legionella pneumonia Abstract. Legionnaire's disease is a usually severe form of pneumonia caused by Legionella pneumophila, a Gram-negative bacterium with an airborne transmission. The infection is acquired in the community, but cases of hospital acquisition from hot water systems have been described. The most common clinical features are cough, fever, gastrointestinal symptoms, hyponatremia and altered liver function tests. The mainstay investigations to confirm diagnosis are urine antigen, sputum polymerase chain reaction, sputum or bronchial alveolar lavage cultures. Standard antibiotic treatment are macrolides or fluoroquinolones.


Assuntos
Legionella pneumophila , Doença dos Legionários , Pneumonia , Antibacterianos , Humanos , Doença dos Legionários/diagnóstico , Doença dos Legionários/tratamento farmacológico , Reação em Cadeia da Polimerase
16.
Proc Natl Acad Sci U S A ; 117(25): 14433-14443, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32513747

RESUMO

During infection, the bacterial pathogen Legionella pneumophila manipulates a variety of host cell signaling pathways, including the Hippo pathway which controls cell proliferation and differentiation in eukaryotes. Our previous studies revealed that L. pneumophila encodes the effector kinase LegK7 which phosphorylates MOB1A, a highly conserved scaffold protein of the Hippo pathway. Here, we show that MOB1A, in addition to being a substrate of LegK7, also functions as an allosteric activator of its kinase activity. A crystallographic analysis of the LegK7-MOB1A complex revealed that the N-terminal half of LegK7 is structurally similar to eukaryotic protein kinases, and that MOB1A directly binds to the LegK7 kinase domain. Substitution of interface residues critical for complex formation abrogated allosteric activation of LegK7 both in vitro and within cells and diminished MOB1A phosphorylation. Importantly, the N-terminal extension (NTE) of MOB1A not only regulated complex formation with LegK7 but also served as a docking site for downstream substrates such as the transcriptional coregulator YAP1. Deletion of the NTE from MOB1A or addition of NTE peptides as binding competitors attenuated YAP1 recruitment to and phosphorylation by LegK7. By providing mechanistic insight into the formation and regulation of the LegK7-MOB1A complex, our study unravels a sophisticated molecular mimicry strategy that is used by L. pneumophila to take control of the host cell Hippo pathway.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Bactérias/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Legionella pneumophila/metabolismo , Proteínas Quinases/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Regulação Alostérica , Animais , Proteínas de Bactérias/genética , Proteínas de Ciclo Celular/metabolismo , Células HEK293 , Interações Hospedeiro-Patógeno , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Legionella pneumophila/patogenicidade , Doença dos Legionários/microbiologia , Doença dos Legionários/patologia , Macrófagos Alveolares/microbiologia , Macrófagos Alveolares/patologia , Camundongos , Simulação de Dinâmica Molecular , Mimetismo Molecular , Fosforilação , Ligação Proteica , Proteínas Quinases/genética , Células RAW 264.7 , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo
17.
Nat Commun ; 11(1): 2864, 2020 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-32513920

RESUMO

Legionella pneumophila is a bacterial pathogen that utilises a Type IV secretion (T4S) system to inject effector proteins into human macrophages. Essential to the recruitment and delivery of effectors to the T4S machinery is the membrane-embedded T4 coupling complex (T4CC). Here, we purify an intact T4CC from the Legionella membrane. It contains the DotL ATPase, the DotM and DotN proteins, the chaperone module IcmSW, and two previously uncharacterised proteins, DotY and DotZ. The atomic resolution structure reveals a DotLMNYZ hetero-pentameric core from which the flexible IcmSW module protrudes. Six of these hetero-pentameric complexes may assemble into a 1.6-MDa hexameric nanomachine, forming an inner membrane channel for effectors to pass through. Analysis of multiple cryo EM maps, further modelling and mutagenesis provide working models for the mechanism for binding and delivery of two essential classes of Legionella effectors, depending on IcmSW or DotM, respectively.


Assuntos
Proteínas de Bactérias/metabolismo , Legionella pneumophila/metabolismo , Sistemas de Secreção Tipo IV/metabolismo , Animais , Proteínas de Bactérias/química , Células CHO , Cricetulus , Modelos Moleculares , Mutação/genética , Mapas de Interação de Proteínas , Multimerização Proteica , Reprodutibilidade dos Testes , Especificidade por Substrato , Sistemas de Secreção Tipo IV/química , Sistemas de Secreção Tipo IV/isolamento & purificação
18.
J Water Health ; 18(3): 345-357, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32589620

RESUMO

The opportunistic, waterborne pathogen Legionella caused 9,933 cases of Legionnaires' disease in 2018 in the United States (CDC.gov). The incidence of Legionnaires' disease can be reduced by maintaining clean building water systems through water management programs (WMPs). WMPs often include validation testing to confirm the control of bacteria, but the traditional culture method for enumerating Legionella requires 10-14 days to obtain results. A rapid DNA extraction developed by Phigenics and a real-time PCR negative screen for the genus Legionella provided results the day after sampling. This study evaluated the Next Day Legionella PCR (Phigenics, LLC) compared with the traditional culture method (ISO 11731) on 11,125 building water samples for approximately 1 year. Two DNA extraction methods (Methods 1 and 2) were compared. The negative predictive value (NPV) of the Next Day Legionella PCR in comparison to traditional culture for Method 1 was 99.95%, 99.92%, 99.85%, and 99.17% at >10, >2, >1, and >0.1 CFU/ml limits of detection, respectively. The improved DNA extraction (Method 2) increased the NPV to 100% and 99.88% at >1 and >0.1 CFU/ml, respectively. These results demonstrate the reliability of the genus-level Legionella PCR negative screen to predict culture-negative water samples.


Assuntos
Ambiente Construído , Legionella , Doença dos Legionários , Humanos , Legionella pneumophila , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos Testes , Estados Unidos , Microbiologia da Água
19.
Int J Infect Dis ; 97: 374-379, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32534142

RESUMO

OBJECTIVES: To report atypical pathogens from clinical trial data comparing delafloxacin to moxifloxacin in the treatment of adults with community-acquired bacterial pneumonia (CABP). METHODS: Multiple diagnostic methods were employed to diagnose atypical infections including culture, serology, and urinary antigen. RESULTS: The microbiological intent-to-treat (MITT) population included 520 patients; 30% had an atypical bacterial pathogen identified (156/520). Overall, 13.1% (68/520) had a monomicrobial atypical infection and 2.3% (12/520) had polymicrobial all-atypical infections. Among patients with polymicrobial infections, Streptococcus pneumoniae was the most frequently occurring co-infecting organism and Chlamydia pneumoniae was the most frequently occurring co-infecting atypical organism. For Mycoplasma pneumoniae and Legionella pneumophila, serology yielded the highest number of diagnoses. Delafloxacin and moxifloxacin had similar in vitro activity against M. pneumoniae and delafloxacin had greater activity against L. pneumophila. Two macrolide-resistant M. pneumoniae isolates were recovered. No fluoroquinolone-resistant M. pneumoniae were isolated. The rates of microbiological success (documented or presumed eradication) at test-of-cure were similar between the delafloxacin and moxifloxacin groups. There was no evidence of a correlation between minimum inhibitory concentration (MIC) and outcome; a high proportion of favorable outcomes was observed across all delafloxacin baseline MICs. CONCLUSIONS: Delafloxacin may be considered a treatment option as monotherapy for CABP in adults, where broad-spectrum coverage including atypical activity is desirable.


Assuntos
Antibacterianos/administração & dosagem , Infecções Comunitárias Adquiridas/tratamento farmacológico , Fluoroquinolonas/administração & dosagem , Moxifloxacina/administração & dosagem , Pneumonia Bacteriana/tratamento farmacológico , Adulto , Infecções Comunitárias Adquiridas/microbiologia , Feminino , Humanos , Legionella pneumophila/efeitos dos fármacos , Legionella pneumophila/crescimento & desenvolvimento , Legionella pneumophila/isolamento & purificação , Macrolídeos/administração & dosagem , Masculino , Testes de Sensibilidade Microbiana , Mycoplasma pneumoniae/efeitos dos fármacos , Mycoplasma pneumoniae/crescimento & desenvolvimento , Mycoplasma pneumoniae/isolamento & purificação , Pneumonia Bacteriana/microbiologia , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/isolamento & purificação , Adulto Jovem
20.
Water Res ; 182: 115943, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32590203

RESUMO

Legionella spp. occurring in hotel hot water systems, in particular Legionella pneumophila, are causing serious pneumonic infections, and water temperature is a key factor to control their occurrence in plumbing systems. We performed a systematic review and meta-analyses of the available evidence on the association between water temperature and Legionella colonization to identify the water temperature in hotel hot water systems required for control of Legionella. Qualitative synthesis and quantitative analysis were performed on 13 studies that met our inclusion criteria to identify the effect of temperature. The Receiver Operating Characteristic (ROC) curve identified 55 °C as a cutoff point for hotel hot water temperature with an Area Under the Curve (AUC) value of 0.914. The odds ratios (OR) for detecting Legionella at temperatures >55 °C compared to lower temperatures from a meta-analysis of three studies was 0.17 [95% CI: 0.11, 0.25], which indicates a strong negative association between temperature and Legionella colonization. A logistic regression on results from multiple studies using both molecular and culture methods found a temperature of 59 °C associated with an 8% probability of detectable Legionella. Only two studies reported sufficiently detailed data to allow a model of concentration vs. temperature to be fit, and this model was not statistically significant. Additional research or more detailed reporting of existing datasets is required to assess if Legionella growth can be limited below particular concentration targets at different temperatures.


Assuntos
Legionella pneumophila , Legionella , Temperatura Alta , Engenharia Sanitária , Temperatura , Água , Microbiologia da Água , Abastecimento de Água
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