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1.
Waste Manag ; 84: 204-210, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30691894

RESUMO

With the rapid growth of the global photovoltaic (PV) industry, the waste from PV industry cannot be ignored, especially the solid wastes from silicon kerf loss and the used quartz crucibles from silicon casting. The silicon kerf loss during wafer sawing was nearly 160,000 tonnes and the used crucible waste was nearly 70,000 tonnes in 2017. With the transition of wafering technology from the slurry-based wire to diamond wire sawing, recycling and reuse of kerf-loss silicon have become more feasible due to the lower impurity contents. In this paper, we aimed to find a simple approach to recycle the kerf loss and identify the purity for reuse. We first analyzed the contents of the as-received kerf-loss silicon from the industry. Then, suitable acids and refining procedure were proposed. The metals, especially nickel, could be easily reduced to several ppmw, boron and phosphorous to sub-ppmw, and carbon to several hundred ppmw, while oxygen was less than 5 wt%. Although the purity of the recycled silicon was not sufficient for casting feedstock, it had a comparable purity of about 5 N with the commercial silicon nitride releasing agent and crucibles used in silicon casting for solar cells. Because the nitride crucibles could be reused a few times for casting, the used crucible waste could be significantly reduced as well.


Assuntos
Diamante , Reciclagem , Indústrias , Metais , Resíduos Sólidos
2.
Med Mal Infect ; 45(7): 264-72, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26028525

RESUMO

OBJECTIVES: A carbapenem-resistant Acinetobacter calcoaceticus-Acinetobacter baumannii complex (CRA complex) infection is one of most the difficult infections to control worldwide. We evaluated the long-term effects of infection control interventions on the incidence densities of healthcare-associated infection (HAI) and CRA complex infection, and the rates of Acinetobacter calcoaceticus-Acinetobacter baumannii complex bacteremia (AB). PATIENTS AND METHODS: We performed a cross-sectional analysis at the Changhua Christian Hospital from January 2002 to December 2013. Interventions for infection control were implemented from 2002 to 2009 (period 1). From 2010 to 2013 (period 2), infection control programs were improved by in-service education and a hand hygiene campaign to prepare for international and national hospital accreditation. The effectiveness of infection and antibiotic control programs was assessed according to the incidence densities of HAI and CRA complex, rates of CRA complex and of AB, chlorhexidine consumption density, and defined daily dose of antibiotics. RESULTS: The incidence density of HAI decreased from 4.56‰ to 1.52‰ from periods 1 to 2 (P<0.001). Likewise, the incidence of AB decreased from 177.79 to 137.76 per person-years per 100,000 admissions (P<0.001). The incidence density of CRA complex ranged from 3.17-7.38‰. The chlorhexidine consumption density increased from 5.5 to 45.5 L per 1000 patient-days (P<0.001). The consumption of piperacillin-tazobactam was lower in period 2 than in period 1 (P<0.001). CONCLUSION: Education for infection control programs, hand hygiene campaigns, and antibiotics control programs may decrease the incidence density of AB and HAI, and may help control CRA complex infection.


Assuntos
Infecções por Acinetobacter/prevenção & controle , Infecções por Acinetobacter/transmissão , Acinetobacter baumannii , Acinetobacter calcoaceticus , Antibacterianos/uso terapêutico , Carbapenêmicos/uso terapêutico , Infecção Hospitalar/prevenção & controle , Infecção Hospitalar/transmissão , Resistência beta-Lactâmica , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Taiwan , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
3.
Eur J Clin Microbiol Infect Dis ; 33(2): 233-9, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23955154

RESUMO

This study investigated the in vitro susceptibilities of methicillin-resistant Staphylococcus aureus (MRSA) to nine antimicrobial agents in Taiwan. A total of 1,725 isolates were obtained from 20 hospitals throughout Taiwan from 2006 to 2010. The minimum inhibitory concentrations (MICs) of the nine agents were determined by the agar dilution method. The MICs of mupirocin and tyrothricin were determined for 223 MRSA isolates collected from 2009 to 2010. For vancomycin, 99.7 % were susceptible; however, 30.0 % (n = 517) exhibited MICs of 2 µg/ml and 0.3 % (n = 6) demonstrated intermediate susceptibility (MICs of 4 µg/ml). Nearly all isolates (≥ 99.9 %) were susceptible to teicoplanin, linezolid, and daptomycin. The MIC90 values were 2 µg/ml for ceftobiprole and 1 µg/ml for nemonoxacin. The MIC90 values of mupirocin and tyrothricin were 0.12 and 4 µg/ml, respectively. MIC creep was noted for daptomycin during this period, but not for vancomycin, teicoplanin, linezolid, or tigecycline. For isolates with vancomycin MICs of 2 µg/ml, the MIC90 values were 2 µg/ml for teicoplanin, 0.5 µg/ml for daptomycin, and 0.5 µg/ml for tigecycline. Those values were four- to eight-fold higher than those among isolates with vancomycin MICs of 0.5 µg/ml (2, 0.06, and 0.12 µg/ml, respectively). Of the nine MRSA isolates exhibiting non-susceptibility to vancomycin (n = 6), teicoplanin (n = 1), daptomycin (n = 2), or tigecycline (n = 1), all had different pulsotypes, indicating the absence of intra-hospital or inter-hospital spread. The presence of a high proportion of MRSA isolates with elevated MICs (2 µg/ml) and MIC creep of daptomycin might alert clinicians on the therapy for serious MRSA infections in Taiwan.


Assuntos
Antibacterianos/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Cefalosporinas/farmacologia , Monitoramento Epidemiológico , Humanos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Quinolonas/farmacologia , Infecções Estafilocócicas/microbiologia , Taiwan , Tirotricina/farmacologia
4.
Transplant Proc ; 45(1): 225-30, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23375305

RESUMO

BACKGROUND: The current study investigated risk factor related to gram-negative bacterial (GNB) infection by Acinetobacter baumannii and non-A baumannii groups, in liver transplantation (OLT) recipients. MATERIALS AND METHODS: All patients with OLT and their living donors were analyzed retrospectively. After excluding those with Gram-positive and fungal infections 89 patients remained in the study including 59 who were noninfected and 30 with GNB infection. The risk factors for GNB infection were classified into the preoperative versus the postoperative periods. RESULTS: GNB-infected patients were classified as non-A baumannii versus A baumannii (15 patients per group). A significant difference was observed in the numbers of intensive care and hospitalized days, hemodialysis requirement, and reoperation frequency compared with the noninfected group. Infection also correlated with hospital mortality, overall survival, and Model for End-Stage Liver Disease (MELD) scores with significance upon univariate but only the last feature on multivariate analysis. CONCLUSIONS: Preoperative MELD scores were more likely to be higher among the non-A baumannii compared with the A baumannii-infected group. However, the 1-year survival of the A baumannii-infected subjects was lower than that of the non-A baumannii infected group.


Assuntos
Infecções por Acinetobacter/complicações , Acinetobacter baumannii , Bactérias Gram-Negativas , Falência Hepática/complicações , Transplante de Fígado/métodos , Fígado/microbiologia , Adulto , Idoso , Antibacterianos/uso terapêutico , Feminino , Humanos , Falência Hepática/microbiologia , Falência Hepática/cirurgia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Adulto Jovem
5.
J Hosp Infect ; 80(2): 162-7, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22188630

RESUMO

BACKGROUND: Varicella zoster infection can be spread by infected healthcare workers (HCWs) to coworkers and patients. A self-reported history of chickenpox infection is sometimes taken as proof of immunity. AIM: To establish the relationship between positive recall history and serological immunity against varicella zoster virus (VZV) amongst healthcare workers in a tertiary hospital in Taiwan. METHODS: Between May 2008 and April 2009, all HCWs in a Taiwanese tertiary care hospital were tested for VZV immunoglobulin G (IgG), and completed a self-administered questionnaire to determine their history of varicella infection or vaccination. Those who were seronegative were vaccinated. FINDINGS: All HCWs (N=3733) at the hospital participated in this study. Their mean age was 34.6 years, and the seroprevalence of VZV was 91.1%. Sensitivity, specificity, and positive and negative predictive values of a self-reported history of varicella infection were 82.3%, 48.6%, 96.3% and 14.4%, respectively. Corresponding figures for a history of varicella vaccination were 23.4%, 69.4%, 90.9% and 6.5%, respectively. The recall history of younger HCWs and medical professionals (doctors, nurses and paramedical staff) to varicella had higher sensitivity. However, only the recall history of medical professionals had a significantly higher positive predictive value. CONCLUSION: A positive recall history of varicella infection and vaccination did not ensure the presence of protective VZV IgG, and a negative history was not predictive of a lack of immunity. For effective prevention of nosocomial infection, VZV IgG status should be documented for all HCWs, and susceptible HCWs should be vaccinated.


Assuntos
Anticorpos Antivirais/sangue , Varicela/epidemiologia , Pessoal de Saúde , Herpesvirus Humano 3/imunologia , Anamnese/métodos , Adolescente , Adulto , Idoso , Feminino , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Soroepidemiológicos , Inquéritos e Questionários , Taiwan/epidemiologia , Adulto Jovem
6.
J Viral Hepat ; 17(8): 578-87, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19818002

RESUMO

In regions that are hyperendemic for chronic hepatitis B virus (HBV) infection, prevalence of and risk factors associated with isolated anti-hepatitis B core antibody (anti-HBc) in HIV-positive patients are less well described. HIV-positive patients who were tested for hepatitis B surface antigen (HBsAg), anti-hepatitis B surface antibody (anti-HBs) and anti-HBc at designated hospitals for HIV care in Taiwan were included for analysis. HBV DNA was detected by real-time polymerase chain reaction in patients with and without isolated anti-HBc. Of 2351 HIV-positive patients, 450 (19.1%) were HBsAg positive, 411 (17.5%) were anti-HBc positive alone and 963 (41.0%) for both anti-HBs and anti-HBc. Compared with patients who were positive for both anti-HBs and anti-HBc, patients with isolated anti-HBc were older, less likely to have anti-hepatitis C virus antibody (anti-HCV), had lower CD4 lymphocyte counts and higher plasma HIV RNA loads. Older age (adjusted odds ratio, 1.029; 95% confidence interval, 1.015-1.043) and CD4 <100 cells/microL (adjusted odds ratio, 1.524; 95% confidence interval, 1.025-2.265) were independently associated with isolated anti-HBc by logistic regression, while presence of anti-HCV and injecting drug use were not. HBV DNA was detectable in 8.3% of 277 patients with isolated anti-HBc and 14.3% of 56 patients with both anti-HBs and anti-HBc (P = 0.160). In a country hyperendemic for HBV infection, HIV-positive patients at older age and with CD4 <100 cells/microL were more likely to have isolated anti-HBc, suggesting that compromised immunity plays a role in the presence of this marker.


Assuntos
Infecções por HIV/complicações , HIV/imunologia , Anticorpos Anti-Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Hepatite B Crônica/complicações , Adolescente , Adulto , Infecções por HIV/epidemiologia , Infecções por HIV/imunologia , Infecções por HIV/virologia , Anticorpos Anti-Hepatite B/sangue , Hepatite B Crônica/epidemiologia , Hepatite B Crônica/imunologia , Hepatite B Crônica/virologia , Humanos , Modelos Logísticos , Pessoa de Meia-Idade , Estudos Retrospectivos , Estudos Soroepidemiológicos , Taiwan/epidemiologia , Adulto Jovem
7.
Infection ; 31(5): 331-5, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14556059

RESUMO

BACKGROUND: Because Acinetobacter baumannii bacteremia is a global problem, we were motivated to characterize this disease in Taiwan. PATIENTS AND METHODS: We analyzed findings in 95 patients with documented A. baumannii bacteremia between January 1, 1998 and December 31, 2000 (47 men, 48 women; mean age 58.8 years). RESULTS: The mean length of stay in the hospital was 44.0 days. Clinically, 76 patients had fever and 35 patients developed shock. Fifty patients had respiratory tract infections; 24, urinary tract infections; 11, intra-abdominal infections; three, CNS infections; and two, catheter-related infections. Five patients had primary bacteremia. Empirical antibiotic therapy was initiated at the onset of the clinical signs of infection. Antimicrobial susceptibility test results were variable. 47 patients died and 48 survived; the mortality rate for A. baumannii bacteremia was 45.3% (43/95). CONCLUSION: Physicians should pay attention to this infection because the early identification of high-risk patients could facilitate prophylaxis and potentially reduce associated problems.


Assuntos
Infecções por Acinetobacter/diagnóstico , Infecções por Acinetobacter/epidemiologia , Acinetobacter baumannii/isolamento & purificação , Bacteriemia/diagnóstico , Bacteriemia/epidemiologia , Infecções por Acinetobacter/tratamento farmacológico , Adulto , Distribuição por Idade , Idoso , Antibacterianos , Bacteriemia/tratamento farmacológico , Estudos Transversais , Quimioterapia Combinada/uso terapêutico , Feminino , Seguimentos , Mortalidade Hospitalar/tendências , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Probabilidade , Estudos Retrospectivos , Medição de Risco , Índice de Gravidade de Doença , Distribuição por Sexo , Taxa de Sobrevida , Taiwan/epidemiologia , Resultado do Tratamento
8.
APMIS ; 109(6): 474-80, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11506481

RESUMO

An outbreak caused by rapid spread of methicillin-resistant Staphylococcus aureus (MRSA) in an intensive care unit for cardiovascular surgery was investigated by phenotypic and genotypic methods. Fourteen isolates were collected during a 2-month period from clinical and environmental specimens in the unit recently re-opened after reconstruction. The isolates were tested for antibiotic susceptibility patterns and genotyped by automated ribotyping, randomly amplified polymorphic DNA-PCR (RAPD) analysis and pulsed-field gel electrophoresis (PFGE). Automated ribotyping applying EcoRI digestion proved to be of no value in separating the isolates. In contrast, PFGE grouped the isolates into four clusters different from the reference strain. These results fully correlated with the antibiograms. Twelve of the isolates were grouped into two clonally related clusters. RAPD analyses grouped the isolates into five clusters. Except for two isolates of one patient, which had different RAPD patterns, PFGE and RAPD analyses presented very similar results. The results verified the usefulness of PFGE in studies of MRSA epidemics. A combination of these two methods reduces the time to identification of an outbreak and increases the accuracy in detection of intraspecies differences.


Assuntos
Infecção Hospitalar/epidemiologia , Surtos de Doenças , Resistência a Meticilina , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Sequência de Bases , Procedimentos Cirúrgicos Cardiovasculares/efeitos adversos , Infecção Hospitalar/microbiologia , Primers do DNA/genética , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Eletroforese em Gel de Campo Pulsado , Humanos , Unidades de Terapia Intensiva , Técnica de Amplificação ao Acaso de DNA Polimórfico , Ribotipagem , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/classificação , Staphylococcus aureus/isolamento & purificação , Centro Cirúrgico Hospitalar , Taiwan/epidemiologia
9.
J Bioenerg Biomembr ; 33(2): 79-92, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11456221

RESUMO

The bacterial histidine permease, an ABC transporter, from Salmonella typhimurium is composed of a membrane-bound complex, HisQMP2, comprising two hydrophobic subunits (HisQ and HisM), two copies of an ATP-hydrolyzing subunit, HisP, and a soluble receptor, HisJ. We describe the purification and characterization of HisQMP2 using a 6-histidines extension at the carboxy terminus of HisP [HisQMP2(his6)]. The purification is rapid and effective, giving a seven-fold purification with a yield of 85 and 98% purity. Two procedures are described differing in the detergent used (decanoylsucrose and octylglucoside, respectively) and in the presence of phospholipid. HisQMP2(his6) has ATPase and transport activities upon reconstitution into proteoliposomes (PLS). HisQMP2(his6) has a low level ATPase activity (intrinsic activity), which is stimulated to a different extent by the receptor--liganded and unliganded. Its pH optimum is 7.8-8.0, it requires a cation for activity and it displays cooperativity for ATP. The effect of various ATP analogs was analyzed. Determination of the molecular size of HisQMP2(his6) indicates that it is a monomer. The permeability properties of two kinds of reconstituted PLS preparations are described.


Assuntos
Transportadores de Cassetes de Ligação de ATP/isolamento & purificação , Sistemas de Transporte de Aminoácidos Básicos/isolamento & purificação , Proteínas de Bactérias/isolamento & purificação , Transportadores de Cassetes de Ligação de ATP/química , Transportadores de Cassetes de Ligação de ATP/metabolismo , Adenosina Trifosfatases/química , Adenosina Trifosfatases/isolamento & purificação , Adenosina Trifosfatases/metabolismo , Sistemas de Transporte de Aminoácidos Básicos/química , Sistemas de Transporte de Aminoácidos Básicos/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Transporte Biológico Ativo , Detergentes , Membranas/química , Peso Molecular , Permeabilidade , Fosfolipídeos/farmacologia , Subunidades Proteicas , Proteolipídeos , Salmonella typhimurium/metabolismo , Solubilidade
10.
J Microbiol Immunol Infect ; 34(2): 119-24, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11456357

RESUMO

The impact of neurologic complications on clinical outcomes in infective endocarditis was assessed. Medical records of patients with infective endocarditis from January 1, 1987 through September 30,1998 were analyzed. Patients were divided into two groups: one with neurological complications and the other without. The outcomes of the two groups were compared using Fisher's exact test. Fifty-eight patients fulfilled the definite Duke criteria. There were 46 men and 12 women, ranging from 3 to 71 years of age with a mean of 40.6 years. Pathogens of infective endocarditis were documented by blood culture in 55 (94.8%) of 58 patients as follows: 52 with gram-positive cocci, two with gram-negative bacilli, and one with fungus. All 58 patients had initially received antimicrobial agents. Eight (13.8%) of the 58 patients had received surgical valvular replacement because of medical treatment failure. Overall, 16 (27.6%) of 58 patients died. Neurologic complications were either the chief complaint or one of the major presenting symptoms in 16 (27.6%) of the 58 patients. Patients with neurologic complications had a higher mortality rate (50% vs 20.9%, p = 0.025) than those without neurologic complications. The adjusted risk ratio for neurologic complications for a fatal event was 3.51 (95% CI = 1.1-11.18, p = 0.03). Neurologic complications pose a significant problem in infective endocarditis. To reduce mortality, we recommend that more attention be paid to the treatment and prevention of the neurologic complications of infective endocarditis.


Assuntos
Hemorragia Cerebral/etiologia , Infarto Cerebral/etiologia , Endocardite Bacteriana/complicações , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Endocardite Bacteriana/mortalidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Taxa de Sobrevida
11.
Nat Med ; 6(10): 1160-6, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11017149

RESUMO

The breaking of immune tolerance against autologous angiogenic endothelial cells should be a useful approach for cancer therapy. Here we show that immunotherapy of tumors using fixed xenogeneic whole endothelial cells as a vaccine was effective in affording protection from tumor growth, inducing regression of established tumors and prolonging survival of tumor-bearing mice. Furthermore, autoreactive immunity targeting to microvessels in solid tumors was induced and was probably responsible for the anti-tumor activity. These observations may provide a new vaccine strategy for cancer therapy through the induction of an autoimmune response against the tumor endothelium in a cross-reaction.


Assuntos
Vacinas Anticâncer/farmacologia , Endotélio/citologia , Endotélio/imunologia , Imunoterapia/métodos , Neoplasias Experimentais/terapia , Sequência de Aminoácidos , Animais , Antígenos CD/imunologia , Autoanticorpos/imunologia , Linfócitos T CD4-Positivos/imunologia , Bovinos , Células Cultivadas , Reações Cruzadas , Endotélio Vascular/citologia , Endotélio Vascular/imunologia , Humanos , Integrina alfaV , Camundongos , Dados de Sequência Molecular , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/imunologia , Peptídeos/imunologia , Receptores Proteína Tirosina Quinases/imunologia , Receptores de Fatores de Crescimento/imunologia , Receptores de Fatores de Crescimento do Endotélio Vascular
12.
J Biol Chem ; 274(26): 18310-8, 1999 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-10373434

RESUMO

The membrane-bound complex of the prokaryotic histidine permease, a periplasmic protein-dependent ABC transporter, is composed of two hydrophobic subunits, HisQ and HisM, and two identical ATP-binding subunits, HisP, and is energized by ATP hydrolysis. The soluble periplasmic binding protein, HisJ, creates a signal that induces ATP hydrolysis by HisP. The crystal structure of HisP has been resolved and shown to have an "L" shape, with one of its arms (arm I) being involved in ATP binding and the other one (arm II) being proposed to interact with the hydrophobic subunits (Hung, L.-W., Wang, I. X., Nikaido, K., Liu, P.-Q., Ames, G. F.-L., and Kim, S.-H. (1998) Nature 396, 703-707). Here we study the basis for the defect of several HisP mutants that have an altered signaling pathway and hydrolyze ATP constitutively. We use biochemical approaches to show that they produce a loosely assembled membrane complex, in which the mutant HisP subunits are disengaged from HisQ and HisM, suggesting that the residues involved are important in the interaction between HisP and the hydrophobic subunits. In addition, the mutant HisPs are shown to have lower affinity for ADP and to display no cooperativity for ATP. All of the residues affected in these HisP mutants are located in arm II of the crystal structure of HisP, thus supporting the proposed function of arm II of HisP as interacting with HisQ and HisM. A revised model involving a cycle of disengagement and reengagement of HisP is proposed as a general mechanism of action for ABC transporters.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Sistemas de Transporte de Aminoácidos Básicos , Proteínas de Bactérias , Proteínas de Membrana Transportadoras/metabolismo , Sítios de Ligação , Transporte Biológico Ativo , Escherichia coli , Hidrólise , Substâncias Macromoleculares , Proteínas de Membrana/metabolismo , Espectrometria de Fluorescência , Tripsina/metabolismo
13.
Zhonghua Yi Xue Za Zhi (Taipei) ; 62(3): 125-32, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10222599

RESUMO

BACKGROUND: Flavobacterium meningosepticum is an uncommon pathogen causing nosocomial pneumonia and meningitis in newborns. It is usually resistant to antimicrobial agents used to treat gram-negative bacilli. While the pathogen often results in high mortality and serious sequelae in newborns, it is also found to cause to disease in adults. Therefore, it is necessary to know the full spectrum of the infection in adults and to identify effective antimicrobial agents. METHOD: Microbiology logbooks were reviewed for F meningosepticum isolated from January, 1992, to March, 1996. The medical records of these patients were reviewed. Special attention was paid to clinical manifestations, underlying diseases, risk factors, treatments, and prognosis. Twenty-four antimicrobial agents were tested using antimicrobial susceptibility tests. RESULTS: Eighteen isolates of F meningosepticum were identified from 16 patients. There were 10 men and six women, with a mean age of 63.7 years. The clinical features of infection included fever (> or = 38 degrees C) in 13 patients, chills in seven, shortness of breath in four, rales or rhonchi in four, shock in three and flank pain in two. All except one patient survived without sequelae. Fifteen patients contracted F meningosepticum from nosocomial sources. Of them, seven were suspected to have acquired the pathogen from diagnostic or therapeutic procedures. Bacteremia occurred in these patients within a mean period of 2.2 days. The other eight patients suffered nosocomial bacteremia within a mean period of 33.4 days after admission. The suspected infection route was not identified in only one patient. The organism was resistant to penicillins, cephalosporins, aztreonam, imipenem, aminoglycosides and macrolides. Testing with lomefloxacin, ciprofloxacin and ofloxacin yielded 72.2%, 83.3% and 94.4% susceptibility rates, respectively. Rifampin (61.1%) and trimethoprim-sulfamethoxazole (TMP-SMX) (88.9%) were effective. Vancomycin and minocycline were 100% effective. CONCLUSIONS: F meningosepticum is an opportunistic pathogen of low virulence and rarely causes serious infections in adults. Reducing the use of unnecessary residual devices and invasive procedures may help reduce the incidence of infection. Therapeutic options include vancomycin, TMP-SMX, minocycline, rifampin or fluoroquinolones.


Assuntos
Bacteriemia/microbiologia , Flavobacterium/isolamento & purificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Bacteriemia/tratamento farmacológico , Feminino , Flavobacterium/efeitos dos fármacos , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade
14.
J Biol Chem ; 274(2): 739-47, 1999 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-9873010

RESUMO

The histidine permease of Salmonella typhimurium is an ABC transporter (traffic ATPase). The liganded soluble receptor, the histidine-binding protein HisJ, interacts with the membrane-bound complex HisQMP2 and stimulates its ATPase activity, which results in histidine translocation. In this study, we utilized HisJ proteins with mutations in either of the two lobes and wild type HisJ liganded with different substrates to show that each lobe carries an interaction site and that both lobes are involved in inducing (stimulating) the ATPase activity. We suggest that the spatial relationship between the lobes is one of the factors recognized by the membrane-bound complex in dictating the efficiency of the induction signal and of translocation. Several of the key residues involved have been identified. In addition, using constitutive ATPase mutants, we show that the binding protein provides some additional essential function(s) in translocation that is independent of the stimulation of ATP hydrolysis, and one possible mechanism is proposed, which includes the notion that liganded HisJ has different optimal conformations for signaling and for translocation.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Sistemas de Transporte de Aminoácidos Básicos , Proteínas de Bactérias , Proteínas de Transporte/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Periplasma/enzimologia , Proteínas Periplásmicas de Ligação , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Proteínas de Transporte/genética , Indução Enzimática , Hidrólise , Ligantes , Mutagênese , Ligação Proteica , Salmonella typhimurium/enzimologia
15.
J Microbiol Immunol Infect ; 31(2): 119-24, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10596990

RESUMO

Eighty-two cases of Acinetobacter calcoaceticus-baumannii complex bacteremia were identified during a 33-month period, from November 1993 to July 1996, at the Veterans General Hospital, Taipei. All cases were due to hospital-acquired infections, with 28 cases of polymicrobial bacteremia. Most patients had severe debilitating conditions: 26 had malignancies, 40 required stay in Intensive Care Unit and 17 had undergone major operations. The main predisposing factors included central venous catheterization, endotracheal intubation or tracheostomy, prior antibiotic therapy and prolonged hospitalization. Amikacin, tobramycin, and ceftazidime were the most effective agents in vitro against A. calcoaceticus-baumannii complex. 32 patients (39 %) died during hospitalization, 19 of the cases (23 %) directly attributed to septicemia. Factors that adversely influenced mortality included polymicrobial bacteremia, inappropriate antimicrobial therapy and prior antibiotic treatment. Of particular interest is the fact that none of the patients who did not receive appropriate antimicrobial therapy survived. Early diagnosis and appropriate antibiotic therapy are critical for improving the prognosis of A. calcoaceticus-baumannii complex bacteremia.


Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter calcoaceticus , Bacteriemia/tratamento farmacológico , Infecções por Acinetobacter/mortalidade , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bacteriemia/mortalidade , Criança , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Estudos Retrospectivos
16.
J Biol Chem ; 272(35): 21883-91, 1997 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-9268321

RESUMO

The superfamily of traffic ATPases (ABC transporters) includes bacterial periplasmic transport systems (permeases) and eukaryotic transporters. The histidine permease of Salmonella typhimurium is composed of a membrane-bound complex (HisQMP2) containing four subunits, and of a soluble receptor, the histidine-binding protein (HisJ). Transport is energized by ATP. In this article the ATPase activity of HisQMP2 has been characterized, using a novel assay that is independent of transport. The assay uses Mg2+ ions to permeabilize membrane vesicles or proteoliposomes, thus allowing access of ATP to both sides of the bilayer. HisQMP2 displays a low level of intrinsic ATPase activity in the absence of HisJ; unliganded HisJ stimulates the activity and liganded HisJ stimulates to an even higher level. All three levels of activity display positive cooperativity for ATP with a Hill coefficient of 2 and a K0. 5 value of 0.6 mM. The activity has been characterized with respect to pH, salt, phospholipids, substrate, and inhibitor specificity. Free histidine has no effect. The activity is inhibited by orthovanadate, but not by N-ethylmaleimide, bafilomycin A1, or ouabain. Several nucleotide analogs, ADP, 5'-adenylyl-beta, gamma-imidodiphosphate, adenosine 5'-(beta,gammaimino)triphosphate, and adenosine 5'-O-(3-thio)triphosphate, inhibit the activity. Unliganded HisJ does not compete with liganded HisJ for the stimulation of the ATPase activity of HisQMP2.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Adenosina Trifosfatases/metabolismo , Sistemas de Transporte de Aminoácidos Básicos , Proteínas de Membrana Transportadoras/metabolismo , Proteínas Periplásmicas de Ligação , Trifosfato de Adenosina/metabolismo , Proteínas de Bactérias/metabolismo , Ligação Competitiva , Transporte Biológico Ativo , Proteínas de Transporte/metabolismo , Escherichia coli , Histidina/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Magnésio/metabolismo , Sulfato de Magnésio/farmacologia , Salmonella typhimurium , Cloreto de Sódio/farmacologia
17.
J Biol Chem ; 272(2): 859-66, 1997 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-8995374

RESUMO

The superfamily of traffic ATPases (ABC transporters) includes bacterial periplasmic transport systems (permeases) and various eukaryotic transporters. The histidine permease of Salmonella typhimurium and Escherichia coli is composed of a membrane-bound complex containing four subunits and of a soluble receptor, the substrate-binding protein (HisJ), and is energized by ATP. The permease was previously reconstituted into proteoliposomes by a detergent dilution method (1). Here we extensively characterize the properties of this permease after reconstitution into proteoliposomes by dialysis and encapsulation of ATP or other reagents by freeze-thawing. We show that histidine transport depends entirely on both ATP and liganded HisJ, with apparent Km values of 8 mM and 8 microM, respectively, and is affected by pH, temperature, and salt concentration. Transport is irreversible and accumulation reaches a plateau at which point transport ceases. The permease is inhibited by ADP and by high concentrations of internal histidine. The inhibition by histidine implies that the membrane-bound complex HisQ/M/P carries a substrate-binding site. The reconstituted permease activity corresponds to about 40-70% turnover rate of the in vivo rate of transport.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Sistemas de Transporte de Aminoácidos Básicos , Proteínas de Bactérias , Membrana Eritrocítica/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Proteolipídeos/metabolismo , Adenosina Trifosfatases/metabolismo , Animais , Transporte Biológico Ativo , Cromatografia em Gel , Glucosídeos/metabolismo , Concentração de Íons de Hidrogênio , Lipossomos/metabolismo , Magnésio/metabolismo
18.
J Biol Chem ; 271(24): 14264-70, 1996 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-8662800

RESUMO

The histidine-binding protein, HisJ, is the soluble receptor for the periplasmic histidine permease of Salmonella typhimurium. The receptor binds the substrate in the periplasm, interacts with the membrane-bound complex, transmits a transmembrane signal to hydrolyze ATP, and releases the ligand for translocation. HisJ, like other periplasmic receptors, has two lobes that are apart in the unliganded structure (open conformation) and drawn close together in the liganded structure (closed conformation), burying deeply the ligand. Such receptors are postulated to interact with the membrane-bound complex with high affinity in their liganded conformation, and, upon substrate translocation, to undergo a reduction in affinity and therefore be released. Here we show that in contrast to the current postulate, liganded and unliganded receptors have equal affinity for the membrane-bound complex. The affinity is measured both by chemical cross-linking and co-sedimentation procedures. An ATPase activity assay is also used to demonstrate the interaction of unliganded receptor with the membrane-bound complex. These findings support a new model for the transport mechanism, in which the soluble receptor functions independently of the commonly accepted high-low affinity switch.


Assuntos
Transportadores de Cassetes de Ligação de ATP , Adenosina Trifosfatases/metabolismo , Sistemas de Transporte de Aminoácidos Básicos , Proteínas de Bactérias , Proteínas de Transporte/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Proteínas Periplásmicas de Ligação , Salmonella typhimurium/metabolismo , Transporte Biológico Ativo , Proteínas de Transporte/isolamento & purificação , Membrana Celular/metabolismo , Reagentes de Ligações Cruzadas/farmacologia , Formaldeído/farmacologia , Histidina/metabolismo , Cinética , Ligantes , Proteínas de Membrana/metabolismo , Proteínas de Membrana Transportadoras/isolamento & purificação , Modelos Estruturais
19.
Zhonghua Yi Xue Za Zhi (Taipei) ; 56(6): 432-5, 1995 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8851486

RESUMO

Lymphocutaneous sporotrichosis and chromoblastomycosis are subcutaneous mycoses caused by traumatic implantation of the fungus into the skin. Medical treatments for chromoblastomycosis has been disappointing, while lymphocutaneous sporotrichosis usually responds well to iodides. Here we present a case of chromomycosis and a case of lymphocutaneous sporotrichosis. Both patients were treated successfully with fluconazole.


Assuntos
Antifúngicos/uso terapêutico , Cromoblastomicose/tratamento farmacológico , Fluconazol/uso terapêutico , Esporotricose/tratamento farmacológico , Adulto , Idoso , Humanos , Masculino
20.
Zhonghua Yi Xue Za Zhi (Taipei) ; 56(3): 173-8, 1995 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8854439

RESUMO

BACKGROUND: Beta-hemolytic streptococci group A, B, and D which cause many diseases have been well studied. Infection caused by group G Streptococcus has increased in clinical significance, and thus is attracting more physicians attention. This retrospective analysis reports clinical experience with such infections at the Veterans General Hospital-Taipei. METHODS: Medical records of invasive group G streptococcal isolates from March 1991 to April 1994 were reviewed. Thirty-seven cases were included. RESULTS: There were 33 males and 4 females with a mean age of 67.4. Major underlying diseases included diabetes (24.3%), cardiovascular diseases (21.6%), malignancy (21.6%), bone or joint diseases (18.9%) and cirrhosis of the liver (13.5%). Only 8.1% cases had no underlying disease. The most common portal of entry was the skin (64.9%). There was a wide spectrum of clinical manifestations, including cellulitis (32.4%), arthritis or osteomyelitis (16.2%), endocarditis (8.1%), meningitis (8.1%), peritonitis (8.1%), empyema (5.4%) and primary bacteremia (27%). All of these isolates were susceptible to penicillin, oxacillin, cefazolin, clindamycin and vancomycin. Ten patients died, and five of these expired from group G streptococcal infections. CONCLUSIONS: Group G Streptococcus is a low virulent microorganism. Clinical improvement after therapy is fast. Poor response to antibiotics should prompt investigation of the underlying diseases or undrained foci of infection.


Assuntos
Infecções Estreptocócicas/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Infecções Estreptocócicas/tratamento farmacológico
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