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1.
BMC Genomics ; 23(1): 510, 2022 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-35836127

RESUMO

BACKGROUND: The SARS-CoV-2 virus is responsible for the COVID-19 pandemic. To better understand the evolution of SARS-CoV-2 early in the pandemic in the Province of Cordoba, Argentina, we performed a comparative genomic analysis of SARS-CoV-2 strains detected in survivors and non-survivors of COVID-19. We also carried out an epidemiological study to find a possible association between the symptoms and comorbidities of these patients with their clinical outcomes. RESULTS: A representative sampling was performed in different cities in the Province of Cordoba. Ten and nine complete SARS-CoV-2 genomes were obtained by next-generation sequencing of nasopharyngeal specimens from non-survivors and survivors, respectively. Phylogenetic and phylodynamic analyses revealed multiple introductions of the most common lineages in South America, including B.1, B.1.1.1, B.1.499, and N.3. Fifty-six mutations were identified, with 14% of those in common between the non-survivor and survivor groups. Specific SARS-CoV-2 mutations for survivors constituted 25% whereas for non-survivors they were 41% of the repertoire, indicating partial selectivity. The non-survivors' variants showed higher diversity in 9 genes, with a majority in Nsp3, while the survivors' variants were detected in 5 genes, with a higher incidence in the Spike protein. At least one comorbidity was present in 60% of non-survivor patients and 33% of survivors. Age 75-85 years (p = 0.018) and hospitalization (p = 0.019) were associated with non-survivor patients. Related to the most common symptoms, the prevalence of fever was similar in both groups, while dyspnea was more frequent among non-survivors and cough among survivors. CONCLUSIONS: This study describes the association of clinical characteristics with the clinical outcomes of survivors and non-survivors of COVID-19 patients, and the specific mutations found in the genome sequences of SARS-CoV-2 in each patient group. Future research on the functional characterization of novel mutations should be performed to understand the role of these variations in SARS-CoV-2 pathogenesis and COVID-19 disease outcomes. These results add new genomic data to better understand the evolution of the SARS-CoV-2 variants that spread in Argentina during the first wave of the COVID-19 pandemic.


Assuntos
COVID-19 , SARS-CoV-2 , Idoso , Idoso de 80 Anos ou mais , Argentina/epidemiologia , COVID-19/epidemiologia , Genoma Viral , Genômica , Humanos , Pandemias , Filogenia , SARS-CoV-2/genética
2.
PLoS Pathog ; 16(8): e1008761, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32790758

RESUMO

The virus-bacterial synergism implicated in secondary bacterial infections caused by Streptococcus pneumoniae following infection with epidemic or pandemic influenza A virus (IAV) is well documented. However, the molecular mechanisms behind such synergism remain largely ill-defined. In pneumocytes infected with influenza A virus, subsequent infection with S. pneumoniae leads to enhanced pneumococcal intracellular survival. The pneumococcal two-component system SirRH appears essential for such enhanced survival. Through comparative transcriptomic analysis between the ΔsirR and wt strains, a list of 179 differentially expressed genes was defined. Among those, the clpL protein chaperone gene and the psaB Mn+2 transporter gene, which are involved in the stress response, are important in enhancing S. pneumoniae survival in influenza-infected cells. The ΔsirR, ΔclpL and ΔpsaB deletion mutants display increased susceptibility to acidic and oxidative stress and no enhancement of intracellular survival in IAV-infected pneumocyte cells. These results suggest that the SirRH two-component system senses IAV-induced stress conditions and controls adaptive responses that allow survival of S. pneumoniae in IAV-infected pneumocytes.


Assuntos
Proteínas de Bactérias/metabolismo , Coinfecção/mortalidade , Vírus da Influenza A/patogenicidade , Influenza Humana/mortalidade , Pulmão/patologia , Infecções Pneumocócicas/mortalidade , Streptococcus pneumoniae/patogenicidade , Proteínas de Bactérias/genética , Sobrevivência Celular , Coinfecção/epidemiologia , Humanos , Influenza Humana/microbiologia , Influenza Humana/patologia , Influenza Humana/virologia , Pulmão/microbiologia , Pulmão/virologia , Infecções Pneumocócicas/microbiologia , Infecções Pneumocócicas/patologia , Infecções Pneumocócicas/virologia , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Streptococcus pneumoniae/metabolismo , Estresse Fisiológico , Virulência
3.
PLoS Pathog ; 14(6): e1007118, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29883472

RESUMO

Streptococcus pneumoniae is an opportunistic human bacterial pathogen that usually colonizes the upper respiratory tract, but the invasion and survival mechanism in respiratory epithelial cells remains elusive. Previously, we described that acidic stress-induced lysis (ASIL) and intracellular survival are controlled by ComE through a yet unknown activation mechanism under acidic conditions, which is independent of the ComD histidine kinase that activates this response regulator for competence development at pH 7.8. Here, we demonstrate that the serine/threonine kinase StkP is essential for ASIL, and show that StkP phosphorylates ComE at Thr128. Molecular dynamic simulations predicted that Thr128-phosphorylation induces conformational changes on ComE's DNA-binding domain. Using nonphosphorylatable (ComET128A) and phosphomimetic (ComET128E) proteins, we confirmed that Thr128-phosphorylation increased the DNA-binding affinity of ComE. The non-phosphorylated form of ComE interacted more strongly with StkP than the phosphomimetic form at acidic pH, suggesting that pH facilitated crosstalk. To identify the ComE-regulated genes under acidic conditions, a comparative transcriptomic analysis was performed between the comET128A and wt strains, and differential expression of 104 genes involved in different cellular processes was detected, suggesting that the StkP/ComE pathway induced global changes in response to acidic stress. In the comET128A mutant, the repression of spxB and sodA correlated with decreased H2O2 production, whereas the reduced expression of murN correlated with an increased resistance to cell wall antibiotic-induced lysis, compatible with cell wall alterations. In the comET128A mutant, ASIL was blocked and acid tolerance response was higher compared to the wt strain. These phenotypes, accompanied with low H2O2 production, are likely responsible for the increased survival in pneumocytes of the comET128A mutant. We propose that the StkP/ComE pathway controls the stress response, thus affecting the intracellular survival of S. pneumoniae in pneumocytes, one of the first barriers that this pathogen must cross to establish an infection.


Assuntos
Ácidos/farmacologia , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Proteínas Serina-Treonina Quinases/metabolismo , Streptococcus pneumoniae/crescimento & desenvolvimento , Estresse Fisiológico , Células A549 , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Humanos , Estresse Oxidativo/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/genética , Streptococcus pneumoniae/efeitos dos fármacos
4.
Int J Med Microbiol ; 305(1): 157-69, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25543170

RESUMO

Streptococcus pneumoniae is a major human pathogen that can survive to stress conditions, such as the acidic environment of inflammatory foci, and tolerates lethal pH through a mechanism known as the acid tolerance response. We previously described that S. pneumoniae activates acidic-stress induced lysis in response to acidified environments, favoring the release of cell wall compounds, DNA and virulence factors. Here, we demonstrate that F(0)F(1)-ATPase is involved in the response to acidic stress. Chemical inhibitors (DCCD, optochin) of this proton pump repressed the ATR induction, but caused an increased ASIL. Confirming these findings, mutants of the subunit c of this enzyme showed the same phenotypes as inhibitors. Importantly, we demonstrated that F(0)F(1)-ATPase and ATR are necessary for the intracellular survival of the pneumococcus in macrophages. Alternatively, a screening of two-component system (TCS) mutants showed that ATR and survival in pneumocytes were controlled in contrasting ways by ComDE and CiaRH, which had been involved in the ASIL mechanism. Briefly, CiaRH was essential for ATR (ComE represses activation) whereas ComE was necessary for ASIL (CiaRH protects against induction). They did not regulate F0F1-ATPase expression, but control LytA expression on the pneumococcal surface. These results suggest that both TCSs and F(0)F(1)-ATPase control a stress response and decide between a survival or a suicide mechanism by independent pathways, either in vitro or in pneumocyte cultures. This biological model contributes to the current knowledge about bacterial response under stress conditions in host tissues, where pathogens need to survive in order to establish infections.


Assuntos
Viabilidade Microbiana , ATPases Translocadoras de Prótons/metabolismo , Transdução de Sinais , Streptococcus pneumoniae/fisiologia , Estresse Fisiológico , Ácidos/toxicidade , Células Epiteliais Alveolares/microbiologia , Animais , Linhagem Celular , Técnicas de Inativação de Genes , Humanos , Concentração de Íons de Hidrogênio , Macrófagos/microbiologia , Camundongos , ATPases Translocadoras de Prótons/genética , Streptococcus pneumoniae/genética
5.
Lancet Oncol ; 15(12): 1351-60, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25273343

RESUMO

BACKGROUND: Longer duration of first-line chemotherapy for patients with metastatic breast cancer is associated with prolonged overall survival and improved progression-free survival. We investigated capecitabine added to maintenance bevacizumab after initial treatment with bevacizumab and docetaxel in this setting. METHODS: We did this open-label randomised phase 3 trial at 54 hospitals in Brazil, China, Egypt, France, Hong Kong, India, Italy, Poland, Spain, and Turkey. We enrolled patients with HER2-negative measurable metastatic breast cancer; each received three to six cycles of first-line bevacizumab (15 mg/kg) and docetaxel (75-100 mg/m(2)) every 3 weeks. Progression-free patients were randomly assigned with an interactive voice-response system by block (size four) randomisation (1:1) to receive either bevacizumab and capecitabine or bevacizumab only (bevacizumab 15 mg/kg on day 1; capecitabine 1000 mg/m(2) twice per day on days 1-14, every 3 weeks) until progression, stratified by oestrogen receptor status (positive vs negative), visceral metastases (present vs absent), response status (stable disease vs response vs non-measurable), and lactate dehydrogenase concentration (≤1·5 vs >1·5 × upper limit of normal). Neither patients nor investigators were masked to allocation. The primary endpoint was progression-free survival (from randomisation) in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT00929240. FINDINGS: Between July 16, 2009, and March 7, 2011 (when enrolment was prematurely terminated), 284 patients received initial bevacizumab and docetaxel; 185 (65%) were randomly assigned (91 to bevacizumab and capecitabine versus 94 to bevacizumab only). Progression-free survival was significantly longer in the bevacizumab and capecitabine group than in the bevacizumab only group (median 11·9 months [95% CI 9·8-15·4] vs 4·3 months [3·9-6·8]; stratified hazard ratio 0·38 [95% CI 0·27-0·55]; two-sided log-rank p<0·0001), as was overall survival (median 39·0 months [95% CI 32·3-not reached] vs 23·7 months [18·5-31·7]; stratified HR 0·43 [95% CI 0·26-0·69]; two-sided log-rank p=0·0003). Results for time to progression were consistent with those for progression-free survival. 78 (86%) patients in the bevacizumab and capecitabine group and 72 (77%) in the bevacizumab only group had an objective response. Clinical benefit was recorded in 92 (98%) patients in the bevacizumab alone group and 90 (99%) in the bevacizumab and capecitabine group. Mean change from baseline in global health score did not differ significantly between groups. Grade 3 or worse adverse events during the maintenance phase were more common with bevacizumab and capecitabine than with bevacizumab only (45 [49%] of 91 patients vs 25 [27%] of 92 patients). The most common grade 3 or worse events were hand-foot syndrome (28 [31%] in the bevacizumab and capecitabine group vs none in the bevacizumab alone group), hypertension (eight [9%] vs three [3%]), and proteinuria (three [3%] vs four [4%]). Serious adverse events were reported by ten (11%) patients in the bevacizumab and capecitabine group and seven (8%) patients in the bevacizumab only group. INTERPRETATION: Despite prematurely terminated accrual and the lack of information about post-progression treatment, both progression-free survival and overall survival were significantly improved with bevacizumab and capecitabine compared with bevacizumab alone as maintenance treatment. These results might inform future maintenance trials and current first-line treatment strategies for HER2-negative metastatic breast cancer. FUNDING: F Hoffmann-La Roche.


Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Neoplasias da Mama/tratamento farmacológico , Desoxicitidina/análogos & derivados , Fluoruracila/análogos & derivados , Taxoides/administração & dosagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Bevacizumab , Neoplasias da Mama/patologia , Capecitabina , China , Desoxicitidina/administração & dosagem , Intervalo Livre de Doença , Docetaxel , Feminino , Fluoruracila/administração & dosagem , Humanos , Estimativa de Kaplan-Meier , Pessoa de Meia-Idade , Receptor ErbB-2/genética
6.
Front Microbiol ; 15: 1423995, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39035445

RESUMO

Streptococcus pneumoniae is a major pathogen responsible for severe complications in patients with prior influenza A virus (IAV) infection. We have previously demonstrated that S. pneumoniae exhibits increased intracellular survival within IAV-infected cells. Fluoroquinolones (FQs) are widely used to treat pneumococcal infections. However, our prior work has shown that S. pneumoniae can develop intracellular FQ persistence, a phenomenon triggered by oxidative stress within host cells. This persistence allows the bacteria to withstand high FQ concentrations. In this study, we show that IAV infection enhances pneumococcal FQ persistence during intracellular survival within pneumocytes, macrophages, and neutrophils. This enhancement is partly due to increased oxidative stress induced by the viral infection. We find that this phenotype is particularly pronounced in autophagy-proficient host cells, potentially resulting from IAV-induced blockage of autophagosome-lysosome fusion. Moreover, we identified several S. pneumoniae genes involved in oxidative stress response that contribute to FQ persistence, including sodA (superoxide dismutase), clpL (chaperone), nrdH (glutaredoxin), and psaB (Mn+2 transporter component). Our findings reveal a novel mechanism of antibiotic persistence promoted by viral infection within host cells. This underscores the importance of considering this phenomenon when using FQs to treat pneumococcal infections, especially in patients with concurrent influenza A infection.

7.
PLoS Pathog ; 7(2): e1002000, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21379570

RESUMO

The prevalence of antibiotic resistance genes in pathogenic bacteria is a major challenge to treating many infectious diseases. The spread of these genes is driven by the strong selection imposed by the use of antibacterial drugs. However, in the absence of drug selection, antibiotic resistance genes impose a fitness cost, which can be ameliorated by compensatory mutations. In Streptococcus pneumoniae, ß-lactam resistance is caused by mutations in three penicillin-binding proteins, PBP1a, PBP2x, and PBP2b, all of which are implicated in cell wall synthesis and the cell division cycle. We found that the fitness cost and cell division defects conferred by pbp2b mutations (as determined by fitness competitive assays in vitro and in vivo and fluorescence microscopy) were fully compensated by the acquisition of pbp2x and pbp1a mutations, apparently by means of an increased stability and a consequent mislocalization of these protein mutants. Thus, these compensatory combinations of pbp mutant alleles resulted in an increase in the level and spectrum of ß-lactam resistance. This report describes a direct correlation between antibiotic resistance increase and fitness cost compensation, both caused by the same gene mutations acquired by horizontal transfer. The clinical origin of the pbp mutations suggests that this intergenic compensatory process is involved in the persistence of ß-lactam resistance among circulating strains. We propose that this compensatory mechanism is relevant for ß-lactam resistance evolution in Streptococcus pneumoniae.


Assuntos
Aminoaciltransferases/genética , Proteínas de Bactérias/genética , Evolução Molecular , Mutação/genética , Proteínas de Ligação às Penicilinas/genética , Peptidil Transferases/genética , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/genética , Resistência beta-Lactâmica/genética , Aminoaciltransferases/química , Aminoaciltransferases/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Divisão Celular , DNA Bacteriano/genética , Citometria de Fluxo , Humanos , Nasofaringe/metabolismo , Proteínas de Ligação às Penicilinas/química , Proteínas de Ligação às Penicilinas/metabolismo , Peptidil Transferases/química , Peptidil Transferases/metabolismo , Infecções Pneumocócicas/tratamento farmacológico , Infecções Pneumocócicas/genética , Infecções Pneumocócicas/microbiologia , Reação em Cadeia da Polimerase , Estabilidade Proteica , Streptococcus pneumoniae/isolamento & purificação , beta-Lactamas/farmacologia
8.
Front Microbiol ; 14: 1269843, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37789846

RESUMO

Streptococcus pneumoniae is a gram-positive, aerotolerant bacterium that naturally colonizes the human nasopharynx, but also causes invasive infections and is a major cause of morbidity and mortality worldwide. This pathogen produces high levels of H2O2 to eliminate other microorganisms that belong to the microbiota of the respiratory tract. However, it also induces an oxidative stress response to survive under this stressful condition. Furthermore, this self-defense mechanism is advantageous in tolerating oxidative stress imposed by the host's immune response. This review provides a comprehensive overview of the strategies employed by the pneumococcus to survive oxidative stress. These strategies encompass the utilization of H2O2 scavengers and thioredoxins, the adaptive response to antimicrobial host oxidants, the regulation of manganese and iron homeostasis, and the intricate regulatory networks that control the stress response. Here, we have also summarized less explored aspects such as the involvement of reparation systems and polyamine metabolism. A particular emphasis is put on the role of the oxidative stress response during the transient intracellular life of Streptococcus pneumoniae, including coinfection with influenza A and the induction of antibiotic persistence in host cells.

9.
Microbiol Spectr ; 10(6): e0436422, 2022 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-36445159

RESUMO

Bacterial persisters represent a small subpopulation that tolerates high antibiotic concentrations without acquiring heritable resistance, and it may be generated by environmental factors. Here, we report the first antibiotic persistence mechanism in Streptococcus pneumoniae, which is induced by oxidative stress conditions and allows the pneumococcus to survive in the presence of fluoroquinolones. We demonstrated that fluoroquinolone persistence is prompted by both the impact of growth arrest and the oxidative stress response induced by H2O2 in bacterial cells. This process protected pneumococci against the deleterious effects of high ROS levels induced by fluoroquinolones. Importantly, S. pneumoniae develops persistence during infection, and is dependent on the oxidative stress status of the host cells, indicating that its transient intracellular life contributes to this mechanism. Furthermore, our findings suggest persistence may influence the outcome of antibiotic therapy and be part of a multistep mechanism in the evolution of fluoroquinolone resistance. IMPORTANCE In S. pneumoniae, different mechanisms that counteract antibiotic effects have been described, such as vancomycin tolerance, heteroresistance to penicillin and fluoroquinolone resistance, which critically affect the therapeutic efficacy. Antibiotic persistence is a type of antibiotic tolerance that allows a bacterial subpopulation to survive lethal antimicrobial concentrations. In this work, we used a host-cell infection model to reveal fluoroquinolone persistence in S. pneumoniae. This mechanism is induced by oxidative stress that the pneumococcus must overcome to survive in host cells. Many fluoroquinolones, such as levofloxacin and moxifloxacin, have a broad spectrum of activity against bacterial pathogens of community-acquired pneumonia, and they are used to treat pneumococcal diseases. However, the emergence of fluoroquinolone-resistant strains complicates antibiotic treatment of invasive infections. Consequently, antibiotic persistence in S. pneumoniae is clinically relevant due to prolonged exposure to fluoroquinolones likely favors the acquisition of mutations that generate antibiotic resistance in persisters. In addition, this work contributes to the knowledge of antibiotic persistence mechanisms in bacteria.


Assuntos
Fluoroquinolonas , Streptococcus pneumoniae , Streptococcus pneumoniae/genética , Fluoroquinolonas/farmacologia , Peróxido de Hidrogênio/farmacologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Levofloxacino/farmacologia , Bactérias , Testes de Sensibilidade Microbiana
10.
J Infect ; 80(1): 24-37, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31606351

RESUMO

Dissemination of methicillin-resistant-Staphylococcus aureus/(MRSA) is a worldwide concern both in hospitals [healthcare-associated-(HA)-MRSA] and communities [community-associated-(CA)-MRSA]. Knowledge on when and where MRSA colonization is acquired and what clones are involved is necessary, to focus efforts for prevention of hospital-acquired MRSA-infections. METHODS: A prospective/longitudinal cohort study was performed in eight Argentina hospitals (Cordoba/ October-December/2014). Surveillance cultures for MRSA (nose-throat-inguinal) were obtained on admission and at discharge. MRSA strains were genetically typed as CA-MRSAG and HA-MRSAG genotypes. RESULTS: Overall, 1419 patients were screened and 534 stayed at hospital for ≥3 days. S. aureus admission prevalence was 30.9% and 4.2% for MRSA. Overall MRSA acquisition rate was 2.3/1000 patient-days-at-risk with a MRSA acquisition prevalence of 1.96% (95%CI: 1.0%-3.4%); 3.2% of patients were discharged back to community with MRSA. CA-MRSAG accounted for 84.6% of imported, 100.0% of hospital-acquired and 94% of discharged MRSA strains. Most imported and acquired MRSA strains belonged to two major epidemic CA-MRSA clones spread in Argentina: PFGEtypeI-ST5-IVa-t311-PVL+ and PFGEtypeN/ST30-IVc-t019-PVL+. CONCLUSIONS: CA-MRSA clones, particularly ST5-IV-PVL+ and ST30-IV-PVL+, with main reservoir in the community, not only enter but also are truly acquired within hospital, causing healthcare-associated-hospital-onset infections, having a transmission capacity greater or similar than HA-MRSAG. This information is essential to develop appropriate MRSA infection prevention-control programs, considering hospital and community.


Assuntos
Infecções Comunitárias Adquiridas , Infecção Hospitalar , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Estudos de Coortes , Infecções Comunitárias Adquiridas/epidemiologia , Infecção Hospitalar/epidemiologia , Exotoxinas , Hospitais , Humanos , Leucocidinas , Estudos Longitudinais , Staphylococcus aureus Resistente à Meticilina/genética , Estudos Prospectivos , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus
11.
J Clin Microbiol ; 46(6): 1930-4, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18417665

RESUMO

Optochin susceptibility is a key test used for pneumococcal diagnosis, but optochin-resistant (Opt(r)) pneumococci have been reported in the last 2 decades. In this work, we characterized eight Opt(r) clinical strains which presented a new mutation, G47V, a predominant A49S mutation (recently reported in Brazil) and A49T. These mutations were found in the c subunit of the F(0)F(1) ATPase encoded by the atpC gene, and W206C was found in the a subunit encoded by the atpA gene. The Opt(r) clinical isolates were analyzed by BOX PCR, multilocus sequence typing, and serotype and antimicrobial resistance profiles, and they showed no epidemiological relationship. To characterize the Opt(r) mutations that could emerge among clinical strains, we studied a pool of spontaneous Opt(r) colonies obtained in vitro from the virulent D39 strain. We compared the atpAC mutations of these Opt(r) pneumococci (with or without passage through C57BL/6 mice) with those described in the clinical isolates. This analysis revealed three new mutations, G47V and L26M in the c subunit and L184S in the a subunit. Most of the mutations identified in the laboratory-generated Opt(r) strains were also found in clinical strains, with the exception of the L26M and L184S mutations, and we suppose that both mutations could emerge among invasive strains in the future. Considering that atpAC are essential genes, we propose that all spontaneous mutations that confer in vitro optochin resistance would not present severe physiological alterations in S. pneumoniae and may be carried by circulating pneumococcal strains.


Assuntos
Farmacorresistência Bacteriana , Quinina/análogos & derivados , Inoculações Seriadas , Streptococcus pneumoniae , Animais , Antibacterianos/farmacologia , Argentina , Proteínas de Bactérias/genética , Criança , Pré-Escolar , Farmacorresistência Bacteriana/genética , Feminino , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Mutação , Infecções Pneumocócicas/microbiologia , ATPases Translocadoras de Prótons/genética , Quinina/farmacologia , Análise de Sequência de DNA , Streptococcus pneumoniae/classificação , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/isolamento & purificação , Streptococcus pneumoniae/patogenicidade , Virulência
12.
J Antimicrob Chemother ; 62(5): 973-7, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18684700

RESUMO

OBJECTIVES: The aim of this work was to study the effect of subinhibitory concentrations of penicillin, chloramphenicol and erythromycin on the mutation rate of Streptococcus pneumoniae. METHODS: The mutation rate to rifampicin and optochin resistance was estimated using fluctuation analysis in three capsulated S. pneumoniae strains, cultured both with and without different subinhibitory antibiotic concentrations. The atpAC and rpoB mutations that conferred optochin and rifampicin resistance, respectively, were identified by DNA sequencing. RESULTS: The exposure to subinhibitory concentrations of penicillin increased the mutation rate (expressed as mutation per cell division) to optochin resistance between 2.1- and 3.1-fold for all three strains studied. In contrast, the rifampicin resistance assay showed no significant variations. To analyse the putative cause of the different responses between the optochin and rifampicin tests, mutations that conferred resistance in both cases were analysed. The difference may be explained by the genetic nature of the atpAC mutations, mostly transversions, which are not efficiently repaired by the HexAB mismatch repair system. CONCLUSIONS: We demonstrated that subinhibitory concentrations of penicillin significantly increased the mutation rate of S. pneumoniae, suggesting that exposure to this antibiotic could help this pathogen to acquire mutations that confer resistance to other antibiotics. The optochin test was useful to detect this phenomenon and it should be considered for further mutability analysis in S. pneumoniae.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Mutagênicos/farmacologia , Mutação de Sentido Incorreto , Penicilinas/farmacologia , Quinina/análogos & derivados , Streptococcus pneumoniae/efeitos dos fármacos , Proteínas de Bactérias/genética , Análise Mutacional de DNA , DNA Bacteriano/química , DNA Bacteriano/genética , RNA Polimerases Dirigidas por DNA/genética , Humanos , Dados de Sequência Molecular , ATPases Translocadoras de Prótons/genética , Quinina/farmacologia , Análise de Sequência de DNA , Streptococcus pneumoniae/genética
13.
J Med Microbiol ; 57(Pt 8): 992-999, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18628501

RESUMO

The penicillin-resistant Spain(9V)-3 clone of Streptococcus pneumoniae is widespread and presents different serotype variants originating from recombination of the capsular genes. In this work, the genetic relatedness of 29 invasive pneumococci isolated from the central region of Argentina (Cordoba, Buenos Aires, Santa Fe and La Pampa provinces) was assessed by multilocus sequence typing (MLST). All of the penicillin-non-susceptible isolates studied (21/29) belonged to a serotype 14 variant of the Spain(9V)-3 clone. This clone was predominant, suggesting that it was responsible for the penicillin resistance spread in this region. Interestingly, this serotype 14 variant (named Cordoba S14V) could be differentiated from the European one by its pbp1a gene, suggesting a different recombinational replacement of the capsular genes. The putative recombination sites were analysed, resulting in the proximal crossover point being clearly localized in the spr0309 gene, with the distal site restricted to the recU gene, confirming a different recombination event. Analysis of the dexB, cpsB, aliA and pbp1a genes from these strains showed a high similarity with the corresponding genes of the Spain(14)-5 clone, suggesting that the capsular genes were provided by this international clone. Analysis of the genetic polymorphisms of the pbp1a (nt 1473-1922) and spr0309 (nt 1-790) genes is proposed as an epidemiological tool to help recognize the Cordoba S14V of the Spain(9V)-3 clone. On the other hand, BOX-repeat-based PCR and MLST analyses of serotype 14 strains revealed a divergent epidemiology of the Cordoba S14V, suggesting a non-recent dissemination in the paediatric population. It is suggested that this molecular epidemiology work will be a reference for monitoring the evolution of S14Vs of Spain(9V)-3, the emergence of new clones and the impact of pneumococcal vaccination programmes in Argentina.


Assuntos
Variação Genética , Streptococcus pneumoniae/classificação , Streptococcus pneumoniae/genética , Argentina , Sequência de Bases , Sangue/microbiologia , Clonagem Molecular , Primers do DNA , Demografia , Humanos , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Sorotipagem , Streptococcus pneumoniae/isolamento & purificação
14.
Anticancer Drugs ; 20 Spec No 1: S1-3, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19352107
15.
ISRN Hepatol ; 2013: 702167, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-27335831

RESUMO

Neuroendocrine tumors (NETs) comprise a heterogeneous group of tumors that form a distinct entity. Approximately 75-80% of patients present with liver metastases at the time of their diagnosis, and 20%-25% will develop these lesions in the course of their disease. The presence of secondary deposits in the liver significantly increases the morbidity and mortality in these patients. The only potentially curative treatment is the surgical resection of the primary tumor and hepatic lesions. However, only 10% of patients presents under ideal conditions for that approach. Several techniques aimed at localized liver lesions have been applied also with interesting results in terms of survival and symptom control. The same has been demonstrated with new systemic therapies (target therapies). However, these are still under study, in order to define their true role in the management of these patients. This paper intends to address, in a general way, the various treatment options in patients with liver metastases from neuroendocrine tumors.

17.
Diagn Microbiol Infect Dis ; 70(1): 145-9, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21513850

RESUMO

Dermatophytic mycetoma is an extremely rare subcutaneous mycosis. Here, we report the case of a 6-year-old girl with clinical, histologic, and mycologic findings consistent with a mycetoma of the scalp caused by Microsporum canis. To our knowledge, this is the first report showing the immunologic and immunogenetic features of a patient with a recalcitrant dermatophytic mycetoma.


Assuntos
Microsporum/isolamento & purificação , Micetoma/diagnóstico , Micetoma/patologia , Couro Cabeludo/microbiologia , Couro Cabeludo/patologia , Antifúngicos/uso terapêutico , Criança , Feminino , Genótipo , Histocitoquímica , Humanos , Microscopia , Microsporum/genética , Tipagem Molecular , Micetoma/microbiologia , Micetoma/terapia , Técnicas de Tipagem Micológica , Reação em Cadeia da Polimerase
18.
Acta Med Port ; 22(5): 525-36, 2009.
Artigo em Português | MEDLINE | ID: mdl-19944035

RESUMO

INTRODUCTION: Cancer is the second most important cause of death in Portugal, following cardiovascular diseases (CVD), and shows a constant progressive increase in the proportional share of total deaths. In Portugal, as in most countries, the health care budget is under constant cost-containment pressures. In this context it is necessary to verify if enough resources have been allocated to the disease in terms of health care expenditure. The main objective of this study is to estimate the cost of cancer care in Portugal and to compare it to similar data in Europe and the United States of America (USA), to the cost of CVD. The secondary objective is to evaluate the cost of pharmaceuticals used in the treatment of cancer in Portugal, both in relation to total pharmaceutical expenditure and to other therapeutic areas. METHODS: Three main sources of information were used: comprehensive literature review, primary and secondary data sources, and a modified Delphi Panel, which was used to fill in gaps in the information derived from the data sources and the literatura review. The burden of cancer was measured through the Disability-adjusted life-year (DALY) and, in order to determine the costs of cancer, detailed information on the costs of medical visits and of inpatient episodes based on Diagnosis Related Groups (DRG), in 2006, was used. To estimate the total cost of cancer, we used a combination of top down (breaking global expenditure data to specific levels) and bottom up methodology (based on the sum of different components). RESULTS: Based on 2006 data on direct medical care expenditures in Portugal, we found that 565 million euro were spent on cancer in comparison to 1 320 million on CVD representing 3.91% and 9.14% of total cost on health respectively. When we break down total expenditure on drugs by therapeutic area we find that CVD drugs represent about 21.6% of total drug costs in Portugal and cancer drugs represent about 5.6% of the total. Oncology drugs represent 32% of the total expenditure on cancer, while CVD drugs represent 54% of the total expenditure on CVD. In comparison, in terms of BoD in Portugal, 18.6% of DALY's were associated with CVD and 15.3% with cancer. CONCLUSION: Considering the burden of disease (BoD) of CVD and cancer in Portugal, we can state that the expenditure allocated to cancer is significantly lower than expected. Using the criterion of expenditure according to need, we observed that there is an imbalance of expense/BoD in oncology indicating that cancer seems to be underfunded in Portugal. Even considering that this shouldn't be the only criterion to determine the volume of expense in a certain therapeutic area, the differential observed in this study is sufficiently high to deserve attention from the decision-makers.


Assuntos
Neoplasias/economia , Neoplasias/terapia , Adolescente , Adulto , Doenças Cardiovasculares/economia , Doenças Cardiovasculares/terapia , Criança , Pré-Escolar , Efeitos Psicossociais da Doença , Europa (Continente) , Humanos , Lactente , Pessoa de Meia-Idade , Portugal , Estados Unidos , Adulto Jovem
19.
Microbiology (Reading) ; 154(Pt 5): 1300-1308, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18451038

RESUMO

In Streptococcus pneumoniae, autolysis is considered a programmed cell-death process executed principally by the major autolysin (LytA), and the underlying mechanism causing its activation is not completely understood. It is known that autolysis is triggered by competence development at alkaline pH and regulated by a two-component system, ComDE, which senses a competence-stimulating peptide (CSP) and behaves as a quorum-sensing mechanism. In this work, we found that acidic stress triggered a LytA-mediated autolysis and, curiously, this phenomenon was regulated by a CSP-independent ComE pathway. A further analysis of a hyperactive ComD mutant revealed that ComE needs to be phosphorylated to activate acidic stress-induced lysis (ASIL). The comE transcripts were induced by acidic culture conditions, suggesting that ComE could be sensing acidic stress. We also investigated CiaRH, a two-component system whose null mutants show a comE derepression and a CSP-dependent autolysis induction at alkaline pH. By analysis of cia comE double mutants, we demonstrated that CiaRH protected cells from ASIL by a ComE-independent pathway. Here, we propose that ComE is the principal route of the signalling pathway that determines a global stress response, and clearly regulates the induction of the LytA-mediated programmed cell death in S. pneumoniae. Acidic stress may represent for S. pneumoniae an alternative condition, in addition to competence and antibiotics, to assure the release of virulence factors, DNA and cell-wall compounds by autolysis, favouring genetic exchange and contributing to its pathogenesis.


Assuntos
Ácidos/farmacologia , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Bacteriólise , Streptococcus pneumoniae/efeitos dos fármacos , Proteínas de Bactérias/genética , Deleção de Genes , Perfilação da Expressão Gênica , Fosforilação , Proteínas Quinases/genética , RNA Bacteriano/biossíntese , RNA Mensageiro/biossíntese
20.
J Clin Microbiol ; 44(1): 192-200, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16390969

RESUMO

Since 1999, a new, epidemic, methicillin-resistant Staphylococcus aureus (MRSA) strain, named the "Cordobes clone," has emerged in Argentina and coexists with the pandemic Brazilian clone. The purpose of this study was to determine the stability over time of the new clone and to investigate its evolutionary relationship with epidemic international MRSA lineages and with other MRSA and methicillin-susceptible S. aureus (MSSA) major clones distributed in this region. One hundred three MRSA isolates recovered in 2001 from Cordoba, Argentina, hospitals and 31 MSSA strains collected from 1999 to 2002 were analyzed by their antibiotic resistance patterns, phage typing, and pulsed-field gel electrophoresis. Additionally, representative members of most MRSA defined genotypes (A, B, C, E, K, and I) were characterized by multilocus sequence typing (MLST) and spaA and SCCmec typing. The most prevalent MSSA pulsotypes were also analyzed by MLST. Our results support the displacement of the Brazilian clone (sequence type [ST] 239, spaA type WGKAOMQ, SCCmec type IIIA) by the Cordobes clone (ST5, spaA type TIMEMDMGMGMK, SCCmec type I) in the hospital environment. MRSA and MSSA isolates shared only ST5. The data support the origin of the Cordobes clone as a member of a lineage that includes the pediatric and New York/Japan international clones and that is genetically related to the British EMRSA-3 strain. Interestingly, the pediatric clone, isolated from most community-acquired infections in Cordoba, was characterized by ST100, a single-locus variant of ST5 and a new variant of SCCmec type related to SCCmec type IVc.


Assuntos
Infecções Comunitárias Adquiridas/microbiologia , Infecção Hospitalar/microbiologia , Evolução Molecular , Resistência a Meticilina/genética , Staphylococcus aureus/genética , Antibacterianos/farmacologia , Argentina/epidemiologia , Técnicas de Tipagem Bacteriana , Hospitais , Humanos , Meticilina/farmacologia , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/isolamento & purificação
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