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1.
Emerg Infect Dis ; 30(3): 608-610, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38407252

RESUMO

We describe a case of endocarditis caused by Streptobacillus moniliformis bacteria, a known cause of rat-bite fever, in a 32-year-old woman with pet rats in Germany. The patient had a strong serologic response, with high IgM and IgG titers. Serologic analysis is a promising tool to identify S. moniliformis bacterial infection.


Assuntos
Endocardite , Streptobacillus , Feminino , Humanos , Animais , Ratos , Adulto , Imunoglobulina G , Imunoglobulina M
2.
Euro Surveill ; 28(1)2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36695452

RESUMO

BackgroundSince the beginning of the war in Ukraine in February 2022, Ukrainians have been seeking shelter in other European countries.AimWe aimed to investigate the prevalence and the molecular epidemiology of multidrug-resistant Gram-negative (MDRGN) bacteria and meticillin-resistant Staphylococcus aureus (MRSA) in Ukrainian patients at admittance to the University Hospital Frankfurt, Germany.MethodsWe performed screening and observational analysis of all patients from March until June 2022. Genomes of MDRGN isolates were analysed for antimicrobial resistance, virulence genes and phylogenetic relatedness.ResultsWe included 103 patients (median age: 39 ±â€¯23.7 years), 57 of whom were female (55.3%; 95% confidence interval (CI): 45.2-5.1). Patients were most frequently admitted to the Department of Paediatrics (29/103; 28.2%; 95% CI: 19.7-37.9). We found 34 MDRGN isolates in 17 of 103 patients (16.5%; 95% CI: 9.9-25.1). Ten patients carried 21 carbapenem-resistant (CR) bacteria, five of them more than one CR isolate. Four of six patients with war-related injuries carried eight CR isolates. In six of 10 patients, CR isolates caused infections. Genomic characterisation revealed that the CR isolates harboured at least one carbapenemase gene, bla NDM-1 being the most frequent (n = 10). Core genome and plasmid analysis revealed no epidemiological connection between most of these isolates. Hypervirulence marker genes were found in five of six Klebsiella pneumoniae CR isolates. No MRSA was found.ConclusionHospitals should consider infection control strategies to cover the elevated prevalence of MDRGN bacteria in Ukrainian patients with war-related injuries and/or hospital pre-treatment and to prevent the spread of hypervirulent CR isolates.


Assuntos
Infecções por Klebsiella , Staphylococcus aureus Resistente à Meticilina , Lesões Relacionadas à Guerra , Humanos , Criança , Feminino , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Masculino , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Filogenia , Lesões Relacionadas à Guerra/tratamento farmacológico , beta-Lactamases/genética , Bactérias , Hospitais Universitários , Alemanha/epidemiologia , Bactérias Gram-Negativas/genética , Klebsiella pneumoniae/genética , Infecções por Klebsiella/tratamento farmacológico
3.
J Clin Microbiol ; 58(12)2020 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-32938741

RESUMO

Mycobacterium abscessus is a highly antibiotic-resistant opportunistic pathogen causing clinically challenging infections in patients with preexisting lung diseases or under immunosuppression. Hence, reliable antibiotic susceptibility data are required for effective treatment. Aims of this study were to investigate (i) the congruence of genotypic and phenotypic antimicrobial susceptibility testing, (ii) the relationship between resistance profile and clinical course, and (iii) the phylogenetic relations of M. abscessus in a German patient cohort. A total of 39 isolates from 29 patients infected or colonized with M. abscessus underwent genotypic and phenotypic drug susceptibility testing. Clinical data were correlated with susceptibility data. Phylogenetic analysis was performed by means of whole-genome sequencing (WGS) and single-nucleotide polymorphism (SNP) analysis. Macrolide resistance was mainly mediated by functional Erm(41) methyltransferases (T28 sequevars) in M. abscessus subsp. abscessus (n = 25) and M. abscessus subsp. bolletii (n = 2). It was significantly associated with impaired culture conversion (P = 0.02). According to the core SNP phylogeny, we identified three clusters of closely related isolates with SNP distances below 25. Representatives of all circulating global clones (Absc. 1, Absc. 2, and Mass. 1) were identified in our cohort. However, we could not determine evidence for in-hospital interhuman transmission from clinical data. In our patient cohort, we identified three M. abscessus clusters with closely related isolates and representatives of the previously described international clusters but no human-to-human in-hospital transmission. Macrolide and aminoglycoside susceptibility data are critical for therapeutic decision-making in M. abscessus infections.


Assuntos
Infecções por Mycobacterium não Tuberculosas , Mycobacterium abscessus , Mycobacterium tuberculosis , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Claritromicina/farmacologia , Farmacorresistência Bacteriana/genética , Humanos , Macrolídeos/farmacologia , Testes de Sensibilidade Microbiana , Infecções por Mycobacterium não Tuberculosas/tratamento farmacológico , Mycobacterium abscessus/genética , Filogenia
5.
Appl Environ Microbiol ; 81(23): 8054-65, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26386064

RESUMO

Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the leading causative agents of food-borne bacterial gastroenteritis. Swift invasion through the intestinal tract and successful establishment in systemic organs are associated with the adaptability of S. Typhimurium to different stress environments. Low-pH stress serves as one of the first lines of defense in mammalian hosts, which S. Typhimurium must efficiently overcome to establish an infection. Therefore, a better understanding of the molecular mechanisms underlying the adaptability of S. Typhimurium to acid stress is highly relevant. In this study, we have performed a transcriptome analysis of S. Typhimurium under the acid tolerance response (ATR) and found a large number of genes (∼47%) to be differentially expressed (more than 1.5-fold or less than -1.5-fold; P < 0.01). Functional annotation revealed differentially expressed genes to be associated with regulation, metabolism, transport and binding, pathogenesis, and motility. Additionally, our knockout analysis of a subset of differentially regulated genes facilitated the identification of proteins that contribute to S. Typhimurium ATR and virulence. Mutants lacking genes encoding the K(+) binding and transport protein KdpA, hypothetical protein YciG, the flagellar hook cap protein FlgD, and the nitrate reductase subunit NarZ were significantly deficient in their ATRs and displayed varied in vitro virulence characteristics. This study offers greater insight into the transcriptome changes of S. Typhimurium under the ATR and provides a framework for further research on the subject.


Assuntos
Ácidos/metabolismo , Regulação Bacteriana da Expressão Gênica , Salmonella typhimurium/genética , Transcriptoma , Perfilação da Expressão Gênica , Concentração de Íons de Hidrogênio , Mutação , Salmonella typhimurium/metabolismo , Análise de Sequência de RNA , Virulência
6.
Vet Microbiol ; 290: 109996, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38295490

RESUMO

Mycoplasma mycoides ssp. capri (Mmc) is one of the etiological microorganisms of contagious agalactia, which is among the diseases causing the highest economical losses in small ruminants. We report a disease outbreak in a German flock that led to significant suffering of goats characterized by mastitis, arthritis, pleuropneumonia and sudden deaths. Mmc was persistently isolated from many animals both from milk, and from a number of different swab and tissue samples. A number of closely related Mycoplasma spp. have to be taken into consideration to rule out important animal epizootics listed by European Animal Health Law and the World Organisation for Animal Health (WOAH). Some goats developed cross-reacting antibodies against Mycoplasma mycoides ssp. mycoides. Although Mmc is believed to be an uncommon microorganism in Germany, this study highlights that veterinarians should consider this pathogen in their work during herd health monitoring in Central Europe. Although eradication was not fully achieved, autogenous vaccination significantly seemed to improve animal health and welfare.


Assuntos
Doenças das Cabras , Mastite , Infecções por Mycoplasma , Mycoplasma mycoides , Mycoplasma , Pleuropneumonia Contagiosa , Feminino , Animais , Cabras , Infecções por Mycoplasma/epidemiologia , Infecções por Mycoplasma/veterinária , Pleuropneumonia Contagiosa/epidemiologia , Mastite/epidemiologia , Mastite/veterinária , Doenças das Cabras/epidemiologia
7.
Microbiol Spectr ; 11(3): e0517422, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-37052493

RESUMO

Acinetobacter baumannii is an antibiotic-resistant, Gram-negative pathogen that causes a multitude of nosocomial infections. However, pathogenicity mechanisms and the host cell response during infection remain unclear. In this study, we determined virulence traits of A. baumannii clinical isolates belonging to the most widely disseminated international clonal lineage, international cluster 2 (IC2), in vitro and in vivo. Complexome profiling of primary human endothelial cells with A. baumannii revealed that mitochondria, and in particular complexes of the electron transport chain, are important host cell targets. Infection with highly virulent A. baumannii remodelled assembly of mitochondrial protein complexes and led to metabolic adaptation. These were characterized by reduced mitochondrial respiration and glycolysis in contrast to those observed in infection with low-pathogenicity A. baumannii. Perturbation of oxidative phosphorylation, destabilization of mitochondrial ribosomes, and interference with mitochondrial metabolic pathways were identified as important pathogenicity mechanisms. Understanding the interaction of human host cells with the current global A. baumannii clone is the basis to identify novel therapeutic targets. IMPORTANCE Virulence traits of Acinetobacter baumannii isolates of the worldwide most prevalent international clonal lineage, IC2, remain largely unknown. In our study, multidrug-resistant IC2 clinical isolates differed substantially in their virulence potential despite their close genetic relatedness. Our data suggest that, at least for some isolates, mitochondria are important target organelles during infection of primary human endothelial cells. Complexes of the respiratory chain were extensively remodelled after infection with a highly virulent A. baumannii strain, leading to metabolic adaptation characterized by severely reduced respiration and glycolysis. Perturbations of both mitochondrial morphology and mitoribosomes were identified as important pathogenicity mechanisms. Our data might help to further decipher the molecular mechanisms of A. baumannii and host mitochondrial interaction during infection.


Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Humanos , Acinetobacter baumannii/genética , Células Endoteliais , Infecções por Acinetobacter/tratamento farmacológico , Farmacorresistência Bacteriana Múltipla/genética , Antibacterianos/farmacologia , Proteínas Mitocondriais/uso terapêutico
8.
Front Cell Infect Microbiol ; 12: 892126, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36093198

RESUMO

Objective: Multidrug-resistant organisms (MDRO), especially carbapenem-resistant organisms (CRO), represent a threat for newborns. This study investigates the colonization prevalence of these pathogens in a newborn unit at a Kenyan tertiary hospital in an integrated approach combining routine microbiology, whole genome sequencing (WGS) and hospital surveillance data. Methods: The study was performed in the Kenyatta National Hospital (KNH) in 2019 over a four-month period and included 300 mother-baby pairs. A total of 1,097 swabs from newborns (weekly), mothers (once) and the hospital environment were taken. Routine clinical microbiology methods were applied for surveillance. Of the 288 detected MDRO, 160 isolates were analyzed for antimicrobial resistance genes and phylogenetic relatedness using whole genome sequencing (WGS) and bioinformatic analysis. Results: In maternal vaginal swabs, MDRO detection rate was 15% (n=45/300), including 2% CRO (n=7/300). At admission, MDRO detection rate for neonates was 16% (n=48/300), including 3% CRO (n=8/300) with a threefold increase for MDRO (44%, n=97/218) and a fivefold increase for CRO (14%, n=29/218) until discharge. Among CRO, K. pneumoniae harboring bla NDM-1 (n=20) or bla NDM-5 (n=16) were most frequent. WGS analysis revealed 20 phylogenetically related transmission clusters (including five CRO clusters). In environmental samples, the MDRO detection rate was 11% (n=18/164), including 2% CRO (n=3/164). Conclusion: Our study provides a snapshot of MDRO and CRO in a Kenyan NBU. Rather than a large outbreak scenario, data indicate several independent transmission events. The CRO rate among newborns attributed to the spread of NDM-type carbapenemases is worrisome.


Assuntos
Infecção Hospitalar , Farmacorresistência Bacteriana Múltipla , Carbapenêmicos , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Feminino , Genômica , Humanos , Lactente , Recém-Nascido , Quênia/epidemiologia , Klebsiella pneumoniae/genética , Filogenia , Estudos Prospectivos , Centros de Atenção Terciária
9.
Lancet Microbe ; 2(12): e685-e694, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-35544109

RESUMO

BACKGROUND: Bartonella bacilliformis is the aetiological agent of Carrión's disease, a biphasic and highly lethal illness formerly restricted to the South American Andes that is now spreading to adjacent areas. Reliable serodiagnostic approaches and vaccines are urgently needed. In this study, we aimed to identify immunodominant proteins of B bacilliformis and to establish novel and reliable serodiagnostic tools. METHODS: We used a reverse vaccinology approach in combination with an analysis of heterologous genomic expression libraries to identify immunodominant proteins, on the basis of the genome sequences of B bacilliformis strains KC583 and KC584. Antigens were screened with serum samples collected from Peruvian patients with B bacilliformis infections and from German healthy blood donors without history of travel to South America. We further analysed immunoreactive proteins of B bacilliformis with immunoblotting and line blots. We used selected target proteins to develop a diagnostic ELISA. To assess the performance of this ELISA, we did receiver operating characteristic analyses to assess the area under the curve, cutoff values, sensitivities, and specificities with 95% CIs. FINDINGS: We used serum samples obtained between Dec 23, 1990, and May 5, 2018, from 26 Peruvian patients with B bacilliformis infections and serum samples taken between Aug 28 and Aug 31, 2020, from 96 healthy German blood donors. 21 potentially immunodominant proteins were identified and recombinantly expressed, and their reactivity was assessed with immunoblotting and line blots. Of these 21 antigens, 14 were found to be immunoreactive. By using serum samples of Peruvian patients with Carrión's disease and of healthy German blood donors, we identified three antigens (porin B, autotransporter E, and hypothetical protein B) as suitable immunodominant antigens, and we applied them in a diagnostic ELISA using two different antigen combinations (porin B plus autotransporter E and porin B plus autotransporter E plus hypothetical protein B). For the combination of porin B and autotransporter E, with optical density measured at 450 nm (OD450) cutoff value of 0·29, sensitivity was 80·8% (95% CI 60·7-93·5) and specificity was 94·8% (88·3-98·3) for all Peruvian patient samples. For a combination of porin B, autotransporter E, and hypothetical protein B, with an OD450 cutoff of 0·34, sensitivity was 76·9% (56·4-91·0) and specificity was 93·8% (86·9-97·7) for all Peruvian patient samples. INTERPRETATION: This novel ELISA could represent a useful serodiagnostic tool for future epidemiological studies of B bacilliformis in endemic areas. Additionally, the immunodominant antigens we have identified could provide a first basis for future vaccine development to prevent the highly lethal Carrión's disease. FUNDING: DRUID (Novel Drug Targets against Poverty-Related and Neglected Tropical Infectious Diseases) Initiative and Robert Koch Institute. TRANSLATIONS: For the Spanish and Quechua translations of the abstract see Supplementary Materials section.


Assuntos
Infecções por Bartonella , Bartonella bacilliformis , Infecções por Bartonella/diagnóstico , Bartonella bacilliformis/genética , Humanos , Epitopos Imunodominantes/metabolismo , Porinas/metabolismo , Sistemas de Secreção Tipo V/metabolismo
10.
Front Microbiol ; 12: 791574, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34880850

RESUMO

Background: Carbapenem-resistant Gram-negative bacteria (CRGN) cause life-threatening infections due to limited antimicrobial treatment options. The occurrence of CRGN is often linked to hospitalization and antimicrobial treatment but remains incompletely understood. CRGN are common in patients with severe illness (e.g., liver transplantation patients). Using whole-genome sequencing (WGS), we aimed to elucidate the evolution of CRGN in this vulnerable cohort and to reconstruct potential transmission routes. Methods: From 351 patients evaluated for liver transplantation, 18 CRGN isolates (from 17 patients) were analyzed. Using WGS and bioinformatic analysis, genotypes and phylogenetic relationships were explored. Potential epidemiological links were assessed by analysis of patient charts. Results: Carbapenem-resistant (CR) Klebsiella pneumoniae (n=9) and CR Pseudomonas aeruginosa (n=7) were the predominating pathogens. In silico analysis revealed that 14/18 CRGN did not harbor carbapenemase-coding genes, whereas in 4/18 CRGN, carbapenemases (VIM-1, VIM-2, OXA-232, and OXA-72) were detected. Among all isolates, there was no evidence of plasmid transfer-mediated carbapenem resistance. A close phylogenetic relatedness was found for three K. pneumoniae isolates. Although no epidemiological context was comprehensible for the CRGN isolates, evidence was found that the isolates resulted of a transmission of a carbapenem-susceptible ancestor before individual radiation into CRGN. Conclusion: The integrative epidemiological study reveals a high diversity of CRGN in liver cirrhosis patients. Mutation of carbapenem-susceptible ancestors appears to be the dominant way of CR acquisition rather than in-hospital transmission of CRGN or carbapenemase-encoding genetic elements. This study underlines the need to avoid transmission of carbapenem-susceptible ancestors in vulnerable patient cohorts.

11.
PLoS One ; 16(1): e0245091, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33481811

RESUMO

OBJECTIVES: Rising prevalence of multidrug-resistant organisms (MDRO) is a major health problem in patients with liver cirrhosis. The impact of MDRO colonization in liver transplantation (LT) candidates and recipients on mortality has not been determined in detail. METHODS: Patients consecutively evaluated and listed for LT in a tertiary German liver transplant center from 2008 to 2018 underwent screening for MDRO colonization including methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant gram-negative bacteria (MDRGN), and vancomycin-resistant enterococci (VRE). MDRO colonization and infection status were obtained at LT evaluation, planned and unplanned hospitalization, three months upon graft allocation, or at last follow-up on the waiting list. RESULTS: In total, 351 patients were listed for LT, of whom 164 (47%) underwent LT after a median of 249 (range 0-1662) days. Incidence of MDRO colonization increased during waiting time for LT, and MRDO colonization was associated with increased mortality on the waiting list (HR = 2.57, p<0.0001. One patients was colonized with a carbapenem-resistant strain at listing, 9 patients acquired carbapenem-resistant gram-negative bacteria (CRGN) on the waiting list, and 4 more after LT. In total, 10 of these 14 patients died. CONCLUSIONS: Colonization with MDRO is associated with increased mortality on the waiting list, but not in short-term follow-up after LT. Moreover, colonization with CRGN seems associated with high mortality in liver transplant candidates and recipients.


Assuntos
Carbapenêmicos , Farmacorresistência Bacteriana Múltipla , Bactérias Gram-Negativas , Infecções por Bactérias Gram-Negativas , Cirrose Hepática , Transplante de Fígado , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Enterococos Resistentes à Vancomicina , Resistência beta-Lactâmica , Adulto , Idoso , Feminino , Seguimentos , Infecções por Bactérias Gram-Negativas/mortalidade , Humanos , Cirrose Hepática/mortalidade , Cirrose Hepática/cirurgia , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Prospectivos , Estudos Retrospectivos , Infecções Estafilocócicas/etiologia , Infecções Estafilocócicas/mortalidade , Centros de Atenção Terciária
12.
Microbiol Resour Announc ; 9(34)2020 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-32816983

RESUMO

Bartonella alsatica causes bacteremia in rabbits and, rarely, human infections. Here, we announce the complete and closed genome of B. alsatica IBS 382 (CIP 105477), generated by long-read Pacific Biosciences single-molecule real-time (SMRT) sequencing. The availability of this genome sequence allows future work on understanding the zoonotic potential of this pathogen.

13.
Microbiol Resour Announc ; 9(1)2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31896649

RESUMO

Bartonella bacilliformis is the biological agent of Carrion's disease, a vector-borne, life-threatening human bartonellosis restricted to South America. Here, we report the complete genome sequence of B. bacilliformis KC584 (ATCC 35686). Although it is commonly used as a reference strain, to date, its complete genome has not been published.

14.
Int J Infect Dis ; 93: 320-328, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32147539

RESUMO

OBJECTIVE: Phenotypic (Sensititre Myco, pDST) and genotypic drug susceptibility testing (GenoType NTM DR, gDST) in M. avium complex (MAC) have become available as standardized assays, but comparable data is needed. This study aimed to investigate the phenotypic and genotypic drug susceptibility patterns in MAC clinical isolates. METHODS: Overall, 98 isolates from 85 patients were included. pDST and gDST were performed on all isolates and results compared regarding specificity and sensitivity using pDST as a reference method. The impact of drug instability on pDST results was studied using a biological assay over 14 days. In addition, the evolution of antimicrobial resistance was investigated in sequential isolates of 13 patients. RESULTS: Macrolide resistance was rare, 1.2% (95% CI 0.7-7.3) of isolates in the base cohort. No aminoglycoside resistances were found, but 14.1% of the studied isolates (95% CI 7.8-23.8) showed intermediate susceptibility. The GenoType NTM DR identified two out of four macrolide-resistant isolates. Antibiotic stability was demonstrated to be poor in rifampicin, rifabutin, and doxycycylin. CONCLUSIONS: pDST results in NTM for unstable antibiotics must be interpreted with care. A combination of pDST and gDST will be useful for the guidance of antimicrobial therapy in MAC-disease.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Complexo Mycobacterium avium/efeitos dos fármacos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Aminoglicosídeos/farmacologia , Criança , Pré-Escolar , Estudos de Coortes , Genótipo , Humanos , Lactente , Macrolídeos/farmacologia , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Complexo Mycobacterium avium/genética , Complexo Mycobacterium avium/isolamento & purificação , Infecção por Mycobacterium avium-intracellulare/microbiologia , Fenótipo , Rifampina , Adulto Jovem
15.
mBio ; 10(5)2019 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-31594810

RESUMO

Cellular sensing of bacterial RNA is increasingly recognized as a determinant of host-pathogen interactions. The intracellular pathogen Listeria monocytogenes induces high levels of type I interferons (alpha/beta interferons [IFN-α/ß]) to create a growth-permissive microenvironment during infection. We previously demonstrated that RNAs secreted by L. monocytogenes (comprising the secRNome) are potent inducers of IFN-ß. We determined the composition and diversity of the members of the secRNome and found that they are uniquely enriched for noncoding small RNAs (sRNAs). Testing of individual sRNAs for their ability to induce IFN revealed several sRNAs with this property. We examined ril32, an intracellularly expressed sRNA that is highly conserved for the species L. monocytogenes and that was the most potent inducer of IFN-ß expression of all the sRNAs tested in this study, in more detail. The rli32-induced IFN-ß response is RIG-I (retinoic acid inducible gene I) dependent, and cells primed with rli32 inhibit influenza virus replication. We determined the rli32 motif required for IFN induction. rli32 overproduction promotes intracellular bacterial growth, and a mutant lacking rli32 is restricted for intracellular growth in macrophages. rli32-overproducing bacteria are resistant to H2O2 and exhibit both increased catalase activity and changes in the cell envelope. Comparative transcriptome sequencing (RNA-Seq) analysis indicated that ril32 regulates expression of the lhrC locus, previously shown to be involved in cell envelope stress. Inhibition of IFN-ß signaling by ruxolitinib reduced rli32-dependent intracellular bacterial growth, indicating a link between induction of the interferon system and bacterial physiology. rli32 is, to the best of our knowledge, the first secreted individual bacterial sRNA known to trigger the induction of the type I IFN response.IMPORTANCE Interferons are potent and broadly acting cytokines that stimulate cellular responses to nucleic acids of unusual structures or locations. While protective when induced following viral infections, the induction of interferons is detrimental to the host during L. monocytogenes infection. Here, we identify specific sRNAs, secreted by the bacterium, with the capacity to induce type I IFN. Further analysis of the most potent sRNA, rli32, links the ability to induce RIG-I-dependent induction of the type I IFN response to the intracellular growth properties of the bacterium. Our findings emphasize the significance of released RNA for Listeria infection and shed light on a compartmental strategy used by an intracellular pathogen to modulate host responses to its advantage.


Assuntos
Fatores Imunológicos/metabolismo , Interferon beta/metabolismo , Listeria monocytogenes/imunologia , Listeria monocytogenes/metabolismo , Macrófagos/microbiologia , RNA Bacteriano/metabolismo , Pequeno RNA não Traduzido/metabolismo , Animais , Células Cultivadas , Deleção de Genes , Listeria monocytogenes/genética , Camundongos Endogâmicos C57BL , RNA Bacteriano/genética , RNA Bacteriano/imunologia , Pequeno RNA não Traduzido/genética , Pequeno RNA não Traduzido/imunologia
16.
Sci Rep ; 8(1): 5392, 2018 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-29599516

RESUMO

Nosocomial pathogens can cause life-threatening infections in neonates and immunocompromised patients. E. bugandensis (EB-247) is a recently described species of Enterobacter, associated with neonatal sepsis. Here we demonstrate that the extended spectrum ß-lactam (ESBL) producing isolate EB-247 is highly virulent in both Galleria mellonella and mouse models of infection. Infection studies in a streptomycin-treated mouse model showed that EB-247 is as efficient as Salmonella Typhimurium in inducing systemic infection and release of proinflammatory cytokines. Sequencing and analysis of the complete genome and plasmid revealed that virulence properties are associated with the chromosome, while antibiotic-resistance genes are exclusively present on a 299 kb IncHI plasmid. EB-247 grew in high concentrations of human serum indicating septicemic potential. Using whole genome-based transcriptome analysis we found 7% of the genome was mobilized for growth in serum. Upregulated genes include those involved in the iron uptake and storage as well as metabolism. The lasso peptide microcin J25 (MccJ25), an inhibitor of iron-uptake and RNA polymerase activity, inhibited EB-247 growth. Our studies indicate that Enterobacter bugandensis is a highly pathogenic species of the genus Enterobacter. Further studies on the colonization and virulence potential of E. bugandensis and its association with septicemic infection is now warranted.


Assuntos
Enterobacter/genética , Infecções por Enterobacteriaceae/patologia , Genoma Bacteriano , Animais , Antibacterianos/farmacologia , Citocinas/metabolismo , Modelos Animais de Doenças , Farmacorresistência Bacteriana/efeitos dos fármacos , Enterobacter/fisiologia , Infecções por Enterobacteriaceae/microbiologia , Infecções por Enterobacteriaceae/mortalidade , Humanos , Camundongos , Antígenos O/química , Antígenos O/imunologia , Plasmídeos/genética , Plasmídeos/metabolismo , Taxa de Sobrevida , Transcriptoma , Virulência/genética , beta-Lactamas/metabolismo
17.
Front Microbiol ; 8: 2463, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29312175

RESUMO

microRNAs (miRNAs) coordinate several physiological and pathological processes by regulating the fate of mRNAs. Studies conducted in vitro indicate a role of microRNAs in the control of host-microbe interactions. However, there is limited understanding of miRNA functions in in vivo models of bacterial infections. In this study, we systematically explored changes in miRNA expression levels of Galleria mellonella larvae (greater-wax moth), a model system that recapitulates the vertebrate innate immunity, following infection with L. monocytogenes. Using an insect-specific miRNA microarray with more than 2000 probes, we found differential expression of 90 miRNAs (39 upregulated and 51 downregulated) in response to infection with L. monocytogenes. We validated the expression of a subset of miRNAs which have mammalian homologs of known or predicted function. In contrast, non-pathogenic L. innocua failed to induce these miRNAs, indicating a virulence-dependent miRNA deregulation. To predict miRNA targets using established algorithms, we generated a publically available G. mellonella transcriptome database. We identified miRNA targets involved in innate immunity, signal transduction and autophagy, including spätzle, MAP kinase, and optineurin, respectively, which exhibited a virulence-specific differential expression. Finally, in silico estimation of minimum free energy of miRNA-mRNA duplexes of validated microRNAs and target transcripts revealed a regulatory network of the host immune response to L. monocytogenes. In conclusion, this study provides evidence for a role of miRNAs in the regulation of the innate immune response following bacterial infection in a simple, rapid and scalable in vivo model that may predict host-microbe interactions in higher vertebrates.

18.
Genome Announc ; 4(5)2016 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-27660771

RESUMO

Lassa virus (LASV) is a zoonotic, hemorrhagic fever-causing virus endemic in West Africa, for which no approved vaccines or specific treatment options exist. Here, we report the genome sequence of LASV isolated from the first case of acquired Lassa fever disease outside of Africa.

19.
Genome Announc ; 4(5)2016 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-27795234

RESUMO

We report here a complete genome sequence of Ebola virus Makona from a nonfatal patient sample that originated in Sierra Leone during the last Ebola virus outbreak in West Africa (species Zaire ebolavirus) using a highly accurate circle sequencing (Cir-seq) method.

20.
Front Microbiol ; 6: 1199, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26579105

RESUMO

Listeria monocytogenes is a bacterial pathogen and causative agent for the foodborne infection listeriosis, which is mainly a threat for pregnant, elderly, or immunocompromised individuals. Due to its ability to invade and colonize diverse eukaryotic cell types including cells from invertebrates, L. monocytogenes has become a well-established model organism for intracellular growth. Almost 10 years ago, we and others presented the first whole-genome microarray-based intracellular transcriptome of L. monocytogenes. With the advent of newer technologies addressing transcriptomes in greater detail, we revisit this work, and analyze the intracellular transcriptome of L. monocytogenes during growth in murine macrophages using a deep sequencing based approach. We detected 656 differentially expressed genes of which 367 were upregulated during intracellular growth in macrophages compared to extracellular growth in Brain Heart Infusion broth. This study confirmed ∼64% of all regulated genes previously identified by microarray analysis. Many of the regulated genes that were detected in the current study involve transporters for various metals, ions as well as complex sugars such as mannose. We also report changes in antisense transcription, especially upregulations during intracellular bacterial survival. A notable finding was the detection of regulatory changes for a subset of temperate A118-like prophage genes, thereby shedding light on the transcriptional profile of this bacteriophage during intracellular growth. In total, our study provides an updated genome-wide view of the transcriptional landscape of L. monocytogenes during intracellular growth and represents a rich resource for future detailed analysis.

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