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1.
Waste Manag ; 84: 204-210, 2019 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-30691894

RESUMEN

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.


Asunto(s)
Diamante , Reciclaje , Industrias , Metales , Residuos Sólidos
2.
Med Mal Infect ; 45(7): 264-72, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26028525

RESUMEN

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.


Asunto(s)
Infecciones por Acinetobacter/prevención & control , Infecciones por Acinetobacter/transmisión , Acinetobacter baumannii , Acinetobacter calcoaceticus , Antibacterianos/uso terapéutico , Carbapenémicos/uso terapéutico , Infección Hospitalaria/prevención & control , Infección Hospitalaria/transmisión , Resistencia betalactámica , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Taiwán , Factores de Tiempo , Resultado del Tratamiento , Adulto Joven
3.
Eur J Clin Microbiol Infect Dis ; 33(2): 233-9, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23955154

RESUMEN

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.


Asunto(s)
Antibacterianos/farmacología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Cefalosporinas/farmacología , Monitoreo Epidemiológico , Humanos , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Quinolonas/farmacología , Infecciones Estafilocócicas/microbiología , Taiwán , Tirotricina/farmacología
4.
Transplant Proc ; 45(1): 225-30, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23375305

RESUMEN

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.


Asunto(s)
Infecciones por Acinetobacter/complicaciones , Acinetobacter baumannii , Bacterias Gramnegativas , Fallo Hepático/complicaciones , Trasplante de Hígado/métodos , Hígado/microbiología , Adulto , Anciano , Antibacterianos/uso terapéutico , Femenino , Humanos , Fallo Hepático/microbiología , Fallo Hepático/cirugía , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Adulto Joven
5.
J Hosp Infect ; 80(2): 162-7, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22188630

RESUMEN

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.


Asunto(s)
Anticuerpos Antivirales/sangre , Varicela/epidemiología , Personal de Salud , Herpesvirus Humano 3/inmunología , Anamnesis/métodos , Adolescente , Adulto , Anciano , Femenino , Humanos , Inmunoglobulina G/sangre , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Seroepidemiológicos , Encuestas y Cuestionarios , Taiwán/epidemiología , Adulto Joven
6.
J Viral Hepat ; 17(8): 578-87, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19818002

RESUMEN

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.


Asunto(s)
Infecciones por VIH/complicaciones , VIH/inmunología , Anticuerpos contra la Hepatitis B/inmunología , Virus de la Hepatitis B/inmunología , Hepatitis B Crónica/complicaciones , Adolescente , Adulto , Infecciones por VIH/epidemiología , Infecciones por VIH/inmunología , Infecciones por VIH/virología , Anticuerpos contra la Hepatitis B/sangre , Hepatitis B Crónica/epidemiología , Hepatitis B Crónica/inmunología , Hepatitis B Crónica/virología , Humanos , Modelos Logísticos , Persona de Mediana Edad , Estudios Retrospectivos , Estudios Seroepidemiológicos , Taiwán/epidemiología , Adulto Joven
7.
Infection ; 31(5): 331-5, 2003 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-14556059

RESUMEN

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.


Asunto(s)
Infecciones por Acinetobacter/diagnóstico , Infecciones por Acinetobacter/epidemiología , Acinetobacter baumannii/aislamiento & purificación , Bacteriemia/diagnóstico , Bacteriemia/epidemiología , Infecciones por Acinetobacter/tratamiento farmacológico , Adulto , Distribución por Edad , Anciano , Antibacterianos , Bacteriemia/tratamiento farmacológico , Estudios Transversales , Quimioterapia Combinada/uso terapéutico , Femenino , Estudios de Seguimiento , Mortalidad Hospitalaria/tendencias , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Probabilidad , Estudios Retrospectivos , Medición de Riesgo , Índice de Severidad de la Enfermedad , Distribución por Sexo , Tasa de Supervivencia , Taiwán/epidemiología , Resultado del Tratamiento
8.
APMIS ; 109(6): 474-80, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11506481

RESUMEN

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.


Asunto(s)
Infección Hospitalaria/epidemiología , Brotes de Enfermedades , Resistencia a la Meticilina , Infecciones Estafilocócicas/epidemiología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/genética , Secuencia de Bases , Procedimientos Quirúrgicos Cardiovasculares/efectos adversos , Infección Hospitalaria/microbiología , Cartilla de ADN/genética , ADN Bacteriano/genética , ADN Bacteriano/aislamiento & purificación , Electroforesis en Gel de Campo Pulsado , Humanos , Unidades de Cuidados Intensivos , Técnica del ADN Polimorfo Amplificado Aleatorio , Ribotipificación , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/clasificación , Staphylococcus aureus/aislamiento & purificación , Servicio de Cirugía en Hospital , Taiwán/epidemiología
9.
J Bioenerg Biomembr ; 33(2): 79-92, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11456221

RESUMEN

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.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/aislamiento & purificación , Sistemas de Transporte de Aminoácidos Básicos/aislamiento & purificación , Proteínas Bacterianas/aislamiento & purificación , Transportadoras de Casetes de Unión a ATP/química , Transportadoras de Casetes de Unión a ATP/metabolismo , Adenosina Trifosfatasas/química , Adenosina Trifosfatasas/aislamiento & purificación , Adenosina Trifosfatasas/metabolismo , Sistemas de Transporte de Aminoácidos Básicos/química , Sistemas de Transporte de Aminoácidos Básicos/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Transporte Biológico Activo , Detergentes , Membranas/química , Peso Molecular , Permeabilidad , Fosfolípidos/farmacología , Subunidades de Proteína , Proteolípidos , Salmonella typhimurium/metabolismo , Solubilidad
10.
J Microbiol Immunol Infect ; 34(2): 119-24, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11456357

RESUMEN

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.


Asunto(s)
Hemorragia Cerebral/etiología , Infarto Cerebral/etiología , Endocarditis Bacteriana/complicaciones , Adolescente , Adulto , Anciano , Niño , Preescolar , Endocarditis Bacteriana/mortalidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Tasa de Supervivencia
11.
Nat Med ; 6(10): 1160-6, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11017149

RESUMEN

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.


Asunto(s)
Vacunas contra el Cáncer/farmacología , Endotelio/citología , Endotelio/inmunología , Inmunoterapia/métodos , Neoplasias Experimentales/terapia , Secuencia de Aminoácidos , Animales , Antígenos CD/inmunología , Autoanticuerpos/inmunología , Linfocitos T CD4-Positivos/inmunología , Bovinos , Células Cultivadas , Reacciones Cruzadas , Endotelio Vascular/citología , Endotelio Vascular/inmunología , Humanos , Integrina alfaV , Ratones , Datos de Secuencia Molecular , Neovascularización Patológica/tratamiento farmacológico , Neovascularización Patológica/inmunología , Péptidos/inmunología , Proteínas Tirosina Quinasas Receptoras/inmunología , Receptores de Factores de Crecimiento/inmunología , Receptores de Factores de Crecimiento Endotelial Vascular
12.
J Biol Chem ; 274(26): 18310-8, 1999 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-10373434

RESUMEN

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.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/metabolismo , Adenosina Trifosfatasas/metabolismo , Adenosina Trifosfato/metabolismo , Sistemas de Transporte de Aminoácidos Básicos , Proteínas Bacterianas , Proteínas de Transporte de Membrana/metabolismo , Sitios de Unión , Transporte Biológico Activo , Escherichia coli , Hidrólisis , Sustancias Macromoleculares , Proteínas de la Membrana/metabolismo , Espectrometría de Fluorescencia , Tripsina/metabolismo
13.
Zhonghua Yi Xue Za Zhi (Taipei) ; 62(3): 125-32, 1999 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10222599

RESUMEN

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.


Asunto(s)
Bacteriemia/microbiología , Flavobacterium/aislamiento & purificación , Adulto , Anciano , Anciano de 80 o más Años , Bacteriemia/tratamiento farmacológico , Femenino , Flavobacterium/efectos de los fármacos , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad
14.
J Biol Chem ; 274(2): 739-47, 1999 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-9873010

RESUMEN

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.


Asunto(s)
Transportadoras de Casetes de Unión a ATP , Sistemas de Transporte de Aminoácidos Básicos , Proteínas Bacterianas , Proteínas Portadoras/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Periplasma/enzimología , Proteínas de Unión Periplasmáticas , Adenosina Trifosfatasas/metabolismo , Adenosina Trifosfato/metabolismo , Proteínas Portadoras/genética , Inducción Enzimática , Hidrólisis , Ligandos , Mutagénesis , Unión Proteica , Salmonella typhimurium/enzimología
15.
J Microbiol Immunol Infect ; 31(2): 119-24, 1998 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10596990

RESUMEN

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.


Asunto(s)
Infecciones por Acinetobacter/tratamiento farmacológico , Acinetobacter calcoaceticus , Bacteriemia/tratamiento farmacológico , Infecciones por Acinetobacter/mortalidad , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Bacteriemia/mortalidad , Niño , Femenino , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Estudios Retrospectivos
16.
J Biol Chem ; 272(35): 21883-91, 1997 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-9268321

RESUMEN

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.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/metabolismo , Adenosina Trifosfatasas/metabolismo , Sistemas de Transporte de Aminoácidos Básicos , Proteínas de Transporte de Membrana/metabolismo , Proteínas de Unión Periplasmáticas , Adenosina Trifosfato/metabolismo , Proteínas Bacterianas/metabolismo , Unión Competitiva , Transporte Biológico Activo , Proteínas Portadoras/metabolismo , Escherichia coli , Histidina/metabolismo , Concentración de Iones de Hidrógeno , Hidrólisis , Cinética , Magnesio/metabolismo , Sulfato de Magnesio/farmacología , Salmonella typhimurium , Cloruro de Sodio/farmacología
17.
J Biol Chem ; 272(2): 859-66, 1997 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-8995374

RESUMEN

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.


Asunto(s)
Transportadoras de Casetes de Unión a ATP , Sistemas de Transporte de Aminoácidos Básicos , Proteínas Bacterianas , Membrana Eritrocítica/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Proteolípidos/metabolismo , Adenosina Trifosfatasas/metabolismo , Animales , Transporte Biológico Activo , Cromatografía en Gel , Glucósidos/metabolismo , Concentración de Iones de Hidrógeno , Liposomas/metabolismo , Magnesio/metabolismo
18.
J Biol Chem ; 271(24): 14264-70, 1996 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-8662800

RESUMEN

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.


Asunto(s)
Transportadoras de Casetes de Unión a ATP , Adenosina Trifosfatasas/metabolismo , Sistemas de Transporte de Aminoácidos Básicos , Proteínas Bacterianas , Proteínas Portadoras/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Proteínas de Unión Periplasmáticas , Salmonella typhimurium/metabolismo , Transporte Biológico Activo , Proteínas Portadoras/aislamiento & purificación , Membrana Celular/metabolismo , Reactivos de Enlaces Cruzados/farmacología , Formaldehído/farmacología , Histidina/metabolismo , Cinética , Ligandos , Proteínas de la Membrana/metabolismo , Proteínas de Transporte de Membrana/aislamiento & purificación , Modelos Estructurales
19.
Zhonghua Yi Xue Za Zhi (Taipei) ; 56(6): 432-5, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8851486

RESUMEN

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.


Asunto(s)
Antifúngicos/uso terapéutico , Cromoblastomicosis/tratamiento farmacológico , Fluconazol/uso terapéutico , Esporotricosis/tratamiento farmacológico , Adulto , Anciano , Humanos , Masculino
20.
Zhonghua Yi Xue Za Zhi (Taipei) ; 56(3): 173-8, 1995 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-8854439

RESUMEN

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.


Asunto(s)
Infecciones Estreptocócicas/etiología , Adulto , Anciano , Anciano de 80 o más Años , Antibacterianos/uso terapéutico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Infecciones Estreptocócicas/tratamiento farmacológico
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