Can copeptin predict the severity of coronavirus disease 2019 infection?

SUMMARY OBJETIVE Coronavirus disease 2019 (COVID-19) has quickly turned into a health problem globally. Early and effective predictors of disease severity are needed to improve the management of the patients affected with COVID-19. Copeptin, a 39-amino acid glycopeptide, is known as a C-terminal unit of the precursor pre-provasopressin (pre-proAVP). Activation of AVP system stimulates copeptin secretion in equimolar amounts with AVP. This study aimed to determine serum copeptin levels in the patients with COVID-19 and to examine the relationship between serum copeptin levels and the severity of the disease. METHODS The study included 90 patients with COVID-19. The patients with COVID-19 were divided into two groups according to disease severity as mild/moderate disease (n=35) and severe disease (n=55). All basic demographic and clinical data of the patients were recorded and blood samples were collected. RESULTS Copeptin levels were significantly higher in the patients with severe COVID-19 compared with the patients with mild/moderate COVID-19 (p<0.001). Copeptin levels were correlated with ferritin and fibrinogen levels positively (r=0.32, p=0.002 and r=0.25, p=0.019, respectively), and correlated with oxygen saturation negatively (r=-0.37, p<0.001). In the multivariate logistic regression analysis, it was revealed that copeptin (OR: 2.647, 95%CI 1.272-5.510; p=0.009) was an independent predictor of severe COVID-19 disease. A cutoff value of 7.84 ng/mL for copeptin predicted severe COVID-19 with a sensitivity of 78% and a specificity of 80% (AUC: 0.869, 95%CI 0.797-0.940; p<0.001). CONCLUSION Copeptin could be used as a favorable prognostic biomarker while determining the disease severity in COVID-19.

Predictive value of plasma copeptin level for diagnosis and mortality of pulmonary embolism

SUMMARY OBJECTIVE: Early diagnosis and risk stratification may provide a better prognosis in pulmonary embolism (PE). Copeptin has emerged as a valuable predictive biomarker in various cardiovascular diseases. The aim of this study was to determine the levels of copeptin in patients with acute PE and to evaluate its relationship with disease severity and PE-related death. METHODS: Fifty-four patients and 60 healthy individuals were included in this study. Copeptin concentrations and right ventricular dysfunction were analyzed. The correlation between copeptin levels and hemodynamic and echocardiographic parameters was examined. After these first measurements, patients were evaluated with PE-related mortality at the one-year follow-up. RESULTS: The copeptin levels were higher in PE patients than in the control group (8.3 ng/mL vs 3.8 ng/mL, p<0.001). Copeptin levels were found to be significantly higher in patients with PE-related death and right ventricular dysfunction (10.2 vs 7.5 ng/ml, p=0.001; 10.5 vs 7.5 ng/ml, p=0.002, respectively). When the cut-off value of copeptin was ≥5.85, its sensitivity and specificity for predicting PE were 71.9% and 85.0%, respectively (AUC=0.762, 95% CI=0.635-0.889, p<0.001). CONCLUSIONS: The copeptin measurement had moderate sensitivity and specificity in predicting the diagnosis of PE, and the copeptin level was significantly higher in patients with PE-related death at the one-year follow-up. Copeptin may be a useful new biomarker in predicting diagnosis, risk stratification, and prognosis of PE.

RESUMO OBJETIVO: O diagnóstico precoce e a estratificação de risco podem proporcionar um melhor prognóstico em casos de embolia pulmonar (EP). A copeptina surgiu como um valioso biomarcador preditivo de várias doenças cardiovasculares. O objetivo deste estudo é determinar os níveis de copeptina em pacientes com EP aguda e avaliar a sua relação com a severidade da doença e mortes relacionadas à EP. MÉTODOS: Um total de 54 pacientes e 60 indivíduos saudáveis foram incluídos neste estudo. As concentrações de copeptina e disfunções ventriculares direitas foram analisadas. A correlação entre os níveis de copeptina e parâmetros ecocardiográficos e hemodinâmicos foi examinada. Após essas primeiras medições, os pacientes foram avaliados em relação à mortalidade relacionada à EP após um ano. RESULTADOS: Os níveis de copeptina foram maiores em pacientes com EP do que no grupo de controle (8,3 ng/mL vs 3,8 ng/mL, p<0,001). Os níveis de copeptina eram significativamente maiores em pacientes com mortes relacionadas à EP e disfunção ventricular direita (10,2 vs 7,5 ng/ml, p=0,001; 10,5 vs 7,5 ng/ml, p=0,002, respectivamente). Com um valor de corte ≥5,85 para a copeptina, sua sensibilidade e especificidade preditivas para EP foram 71,9% e 85,0%, respectivamente (AUC=0,762, 95% IC=0,635 - 0,889, p<0,001). CONCLUSÃO: A medição da copeptina teve sensibilidade e especificidade preditivas moderadas para o diagnóstico de EP, e o nível de copeptina foi significativamente maior em pacientes com mortes relacionadas à EP após um ano. A copeptina pode ser um novo biomarcador preditivo útil para o diagnóstico, a estratificação de risco e o prognóstico de PE.

Impression cytology in the evaluation of ocular surface tumors: review article / Citologia de impressão na avaliação de tumores da superfície ocular: artigo de revisão

Impression cytology (IC) has been widely used as a method for evaluating the ocular surface and superficial cells layers in the diagnosis and follow-up after treatment of several ocular surface tumors of both epithelial and melanocytic origin. Information regarding this can be found in the English-language literature since 1992. Using either cellulose acetate or Biopore membranes for specimen collection, a high correlation has been found between IC and tissue histology. Compared with exfoliative cytology with spatula, IC is less traumatic to the patient’s eye, provides a precise location of the area being studied, and allows accurate observation of the cells the way they exist in vivo. The additional advantage of IC is the preservation of limbal stem cells responsible for continuous corneal epithelium renewal; these can be affected after incisional or excisional biopsy at the corneoscleral limbus, which is the most frequent site of appearance of tumors in the stratified epithelium. Treatment for ocular surface squamous neoplasia has historically included surgery, but nonsurgical interventions have also been adopted. Hence, in certain cases, ophthalmologists may prefer interventions less invasive than surgical biopsy such as of impression cytology for both initial diagnosis and therapeutic monitoring of treatment for ocular surface lesions. Nevertheless, it should be considered that IC may be less helpful if the results conflict with the clinical picture or if the clinical diagnosis is uncertain and results are negative. In such cases, surgical biopsy is required for accurate diagnosis. The purpose of this review is to examine the published literature on the utilization of IC for the diagnosis and management of ocular surface tumors and to discuss the requirement for further investigation on the subject.

A citologia de impressão (CI) tem sido amplamente utilizada como um método de avaliação da superfície ocular e das camadas de células superficiais no diagnóstico e no seguimento após tratamento de vários tumores da superfície ocular de origem epitelial ou melanocítica. As informações podem sem encontradas na literatura em língua inglesa desde 1992. Utilizando-se de membranas de acetato de celulose ou Biopore na coleta dos espécimes, uma alta correlação tem sido encontrada entre a CI e a histologia do tecido. Comparando-se com a citologia esfoliativa, a citologia de impressão é menos traumática para o olho do paciente, fornece uma localização precisa da área estudada e permite ver as células da forma como elas organizam-se in vivo. A vantagem adicional da citologia de impressão é a preservação das células- tronco germinativas responsáveis pela renovação contínua do epitélio da córnea. Elas podem ser afetadas após biópsia cirúrgica na região do limbo que é o sítio mais frequentemente acometido pelos tumores do epitélio estratificado. O tratamento para a neoplasia escamosa da superfície ocular tem sido historicamente a cirurgia, mas intervenções não cirúrgicas também foram adotadas. Por esta razão, em certos casos, oftalmologistas podem recorrer a formas menos invasivas que a biópsia cirúrgica (como a citologia de impressão) tanto para o diagnóstico inicial quanto para o monitoramento terapêutico das lesões da superfície ocular. No entanto, deve-se ter em mente que a citologia de impressão deixa de ser útil quando seu resultado não coincide com o quadro clínico ou quando o diagnóstico clínico é incerto e o resultado da citologia de impressão negativo. Nesses casos, a biópsia cirúrgica deve ser realizada para o diagnóstico. O objetivo desta revisão é examinar a literatura sobre a utilização da citologia de impressão no diagnóstico e tratamento dos tumores da superfície ocular bem como discutir a necessidade de uma investigação mais aprofundada sobre o assunto.

Glicopéptidos, origen y desarrollo actual / Glycopeptids, origin and current development

Presidente del capítulo cubano de APUA-Cuba, Alianza para el Uso Prudente de los Antibióticos Lejos estaba de pensar Mc Cormick, en 1955, cuando en tierras de Borneo, aislaba una cepa de Stretomyces orientalis productora de una sustancia con propiedades antimicrobianas, que nombró vancomicina y que 60 años después permanecería en la primera línea de tratamiento contra las infecciones por microorganismo grampositivos multirresistentes. La vancomicina, nombre proveniente de la palabra vanquish, que significa vencedor, recibió el sobrenombre de fango del Missipi, debido a su gran toxicidad, fue relegada a un segundo plano con la aparición, en 1958, de la primera penicilina antiestafilocócica (meticillina). Sin embargo, en fecha tan temprana como el comienzo de la década de los 60, hubo que retomar su uso, debido a la aparición de las primeras cepas de estafilococos meticillina resistente. Estas cepas, con el de cursar de los años, han aumento y diseminado por todo el planeta, robándose el protagonismo de las infecciones asociadas a la asistencia sanitaria. En la actualidad, más del 50 por ciento de las cepas de Stafilococcus aureus aisladas en el nosocomio son meticillina resistentes y alcanzan más del 70 por ciento en la mayoría de las unidades de cuidados intensivos. Debido al mecanismo de resistencia presente en estas, a través de una mutación genética (gen mecA), resisten la acción de todos los betalactámicos, incluso de los aminoglucósidos, quinolonas, rifampicina, macrólidos y otros antiestafilócicos, quedando pocos antimicrobianos disponibles para enfrentarlas, entre los que sobresalen, los glicopéptidos, encabezados por la vancomicina.1,2 El desarrollo de la familia de los glicopéptidos ha sido discreto, la aparición, en 1978, de la teicoplanina, aportó algunos avances como la aplicación intramuscular, vida media más prolongada e incluso poder eliminar algunas cepas resistentes a vancomicina (vanB). Posteriormente, hubo que esperar hasta 2009 para que apareciera un nuevo componente de dicha familia, la telavancina, derivada de la vancomicina y con una potente acción sobre las cepas de estafilococos y enterococos resistentes a vancomicina.3,4 Tras más de 10 años de investigación, en el 2014, se introducen en la asistencia médica dos nuevos componentes de dicha familia la oritavancina (derivada de la vancomicina) y dalbavancina (derivada de la teicoplanina), ambas con características farmacológicas...(AU)

Factors associated with Clostridium difficile diarrhea in a hospital in Beijing, China

Clostridium difficile is the most common cause of hospital-acquired diarrhea in patients treated with antibiotics, chemotherapeutic agents, and other drugs that alter the normal equilibrium of the intestinal flora. A better understanding of the risk factors for C. difficile-associated disease (CDAD) could be used to reduce the incidence of CDAD and the costs associated with its treatment. The aim of this study was to identify the risk factors for CDAD in a cohort of Chinese patients in a Beijing hospital. Medical charts of a total of 130 inpatients (62 males and 68 females) with hospital-acquired diarrhea (45 with CDAD; 85 without CDAD) were retrospectively reviewed. C. difficile toxins A and B were detected in fecal samples using enzyme-linked fluorescence assays. The drugs used by patients with and without CDAD before the onset of diarrhea were compared. Factors that differed significantly between the two groups by univariate analysis were analyzed by multivariate analysis using a logistic regression model. Multivariate analysis showed that cephalosporin treatment was associated with a significantly higher risk of CDAD in hospitalized patients, while treatment with glycopeptides was significantly associated with a reduction in CDAD (P<0.001 for cephalosporin; P=0.013 for glycopeptides). Our data confirmed previous findings that empirical treatment with cephalosporins is positively associated with CDAD compared to individuals using other CDAD-related drugs. Additionally, we showed that treatment with glycopeptides was negatively associated with CDAD, compared to individuals using other CDAD-related drugs.

Evaluación de la susceptibilidad a glicopéptidos en cepas de Staphylococcus aureus resistentes a oxacilina / Evaluation of susceptibility to glycopeptides in oxacillin resistant Staphylococcus aureus strains

Candida albicans y Candida dubliniensis presentan una estrecha relación filogenética. La similitud de estas especies puede hacer que en un laboratorio microbiológico se identifique en forma errónea C. dubliniensis como C. albicans. El objetivo de esta investigación fue evaluar diversos métodos fenotípicos para la diferenciación entre Candida dubliniensis y Candida albicans. Se utilizaron 6 cepas control de C. dubliniensis y una de C. albicans, provenientes de colecciones reconocidas y sometidas a genotipificación. También se utilizaron 70 aislados identificados como posibles C. albicans utilizando el medio CHROMagar Candida y el medio de bilis agar Feo. Los métodos evaluados fueron: agar Sabouraud dextrosa a 45°C, agar Sabouraud con NaCl al 6,5%, agar Tween 80, agar tabaco, agar Pal’s, agar tomate-zanahoria y aglutinación con partículas de látex (Bichro-Dubli Fumouze®). Encontramos que las técnicas más confiables para realizar la diferenciación fenotípica entre estas dos especies fueron: el agar tomate-zanahoria, el agar Pal’s, el agar tabaco y la aglutinación con partículas de látex (Bichro-Dubli Fumouze®). Además en este estudio, de los 70 aislados considerados como C. albicans, encontramos 1 (1.4%) posible Candida dubliniensis. Sin embargo, las pruebas de biología molecular son las más adecuadas para el diagnóstico certero de estas dos especies.

Candida albicans and Candida dubliniensis have a close phylogenetic relationship. The similarity between these species can cause a microbiology laboratory to identify C. dubliniensis erroneously as C. albicans. The objective of this research was to evaluate diverse phenotypic methods for differentiating between Candida dubliniensis and Candida albicans. Six control strains of C. dubliniensis and one of C. albicans from recognized collections were used and submitted to genotypification. Also, 70 isolates were used, identified as possible C. albicans utilizing CHROMagar Candida and bilis agar Feo mediums. The methods evaluated were: Sabouraud dextrosa agar at 45°C, Sabouraud agar with NaCl at 6.5%, Tween 80 agar, tobacco agar, Pal’s agar, tomato-carrot agar and agglutination with latex particles (Bichro-Dubli Fumouze®). It was found that the most reliable techniques for performing phenotype differentiation between these two species were tomato-carrot agar, Pal’s agar, tobacco agar and agglutination with latex particles (Bichro-Dubli Fumouze®). Of the 70 isolates considered to be C. albicans, one (1.4%) possible Candida dubliniensis was found. Nevertheless, molecular biology tests are the most appropriate means for achieving an accurate diagnosis of these two species.

Comparação da acurácia de preditores de mortalidade na pneumonia associada à ventilação mecânica / Comparing the accuracy of predictors of mortality in ventilator-associated pneumonia

OBJETIVO: Níveis de procalcitonina, midregional pro-atrial natriuretic peptide (MR-proANP, pró-peptídeo natriurético atrial midregional),, C-terminal provasopressin (copeptina), proteína C reativa (CRP) e escore do Sequential Organ Failure Assessment (SOFA) são associados a gravidade e descritos como preditores de desfechos na pneumonia associada a ventilação mecânica (PAVM). Este estudo procurou comparar o valor preditivo de mortalidade desses biomarcadores na PAVM. MÉTODOS: Estudo observacional com 71 pacientes com PAVM. Níveis de procalcitonina, MR-proANP, copeptina e PCR, bem como escore de SOFA foram obtidos no dia do diagnóstico de PAVM, designado dia zero (D0), e no quarto dia de tratamento (D4) Os pacientes receberam tratamento antimicrobiano empírico, com modificações baseadas nos resultados de cultura. Os pacientes que morreram antes de D28 foram classificados como não sobreviventes. RESULTADOS: Dos 71 pacientes, 45 sobreviveram. Dos 45 sobreviventes, 35 (77,8 por cento) receberam tratamento antimicrobiano adequado, comparados com 18 (69,2 por cento) dos 26 não sobreviventes (p = 0,57). Os sobreviventes apresentaram valores significativamente mais baixos em todos os biomarcadores estudados, inclusive no escore de SOFA (exceto PCR) em D0 e D4. Em D0 e D4, a área sob a curva ROC foi maior para procalcitonina. Em D0, MR-proANP teve a maior razão de verossimilhança positiva (2,71) e valor preditivo positivo (0,60), mas a procalcitonina apresentou o maior valor preditivo negativo (0,87). Em D4, a procalcitonina apresentou a maior razão de verossimilhança positiva (3,46), o maior valor preditivo positivo (0,66) e o maior valor preditivo negativo (0,93). CONCLUSIONS: Os biomarcadores procalcitonina, MR-proANP e copeptina podem predizer mortalidade na PAVM, assim como o escore de SOFA. A procalcitonina tem o maior poder preditivo de mortalidade na PAVM.

OBJECTIVE: Levels of procalcitonin, midregional pro-atrial natriuretic peptide (MR-proANP), C-terminal provasopressin (copeptin), and C-reactive protein (CRP), as well as Sequential Organ Failure Assessment (SOFA) scores, are associated with severity and described as predictors of outcome in ventilator-associated pneumonia (VAP). This study sought to compare the predictive value of these biomarkers for mortality in VAP. METHODS: An observational study of 71 patients with VAP. Levels of procalcitonin, MR-proANP, copeptin, and CRP, together with SOFA scores, were determined at VAP onset, designated day 0 (D0), and on day 4 of treatment (D4). Patients received empirical antimicrobial therapy, with modifications based on culture results. Patients who died before D28 were classified as nonsurvivors. RESULTS: Of the 71 patients evaluated, 45 were classified as survivors. Of the 45 survivors, 35 (77.8 percent) received appropriate antimicrobial therapy, compared with 18 (69.2 percent) of the 26 nonsurvivors (p = 0.57). On D0 and D4, the levels of all biomarkers (except CRP), as well as SOFA scores, were lower in eventual survivors than in eventual nonsurvivors. For D0 and D4, the area under the ROC curve was largest for procalcitonin. On D0, MR-proANP had the highest positive likelihood ratio (2.71) and positive predictive value (0.60), but procalcitonin had the highest negative predictive value (0.87). On D4, procalcitonin had the highest positive likelihood ratio (3.46), the highest positive predictive value (0.66), and the highest negative predictive value (0.93). CONCLUSIONS: The biomarkers procalcitonin, MR-proANP, and copeptin can predict mortality in VAP, as can the SOFA score. Procalcitonin alone has the greatest predictive power for such mortality.

Comparative analysis of two component signal transduction systems of the Lactobacillus acidophilus group

The Lactobacillus acidophilus group is a phylogenetically distinct group of closely related lactobacilli. Members of this group are considered to have probiotic properties and occupy different environmental niches. Bacteria generally sense and respond to environmental changes through two component systems (TCSs) which consist of a histidine protein kinase (HPK) and its cognate response regulator (RR). With the use of in silico techniques, the five completely sequenced L. acidophilus group genomes were scanned in order to predict TCSs. Five to nine putative TCSs encoding genes were detected in individual genomes of the L. acidophilus group. The L. acidophilus group HPKs and RRs were classified into subfamilies using the Grebe and Stock classification method. Putative TCSs were analyzed with respect to conserved domains to predict biological functions. Putative biological functions were predicted for the L. acidophilus group HPKs and RRs by comparing them with those of other microorganisms. Some of TCSs were putatively involved in a wide variety of functions which are related with probiotic ability, including tolerance to acid and bile, production of antimicrobial peptides, resistibility to the glycopeptide antibiotic vancomycin, and oxidative condition.

Oxacilin-resistant Coagulase-negative staphylococci (CoNS) bacteremia in a general hospital at São Paulo city, Brasil / Bacteremias por Staphylococcus coagulase negativos oxacilina resistentes em um hospital na cidade de São Paulo, Brasil

In the last decades, coagulase-negative staphylococci (CoNS), especially Staphylococcus epidermidis have become an important cause of bloodstream infections. In addition, rates of methicillin-resistance among CoNS have increased substantially, leading to the use of glicopeptides for therapy. The objective of this study was to evaluate eleven consecutives clinically relevant cases of oxacillin-resistant CoNS bacteremia in a general hospital localized in São Paulo city, Brazil. Five different species were identified by different phenotypic methods, including S. epidermidis (5), S. haemolyticus (3), S. hominis (1), S. warneri (1) and S. cohnii subsp urealyticus (1). A variety of Pulsed Field Gel Electrophoresis profiles was observed by macrorestriction DNA analysis in S. epidermidis isolates, but two of three S. haemolyticus isolates presented the same profile. These data indicated the heterogeneity of the CoNS isolates, suggesting that horizontal dissemination of these microorganisms in the investigated hospital was not frequent. One S. epidermidis and one S. haemolyticus isolates were resistant to teicoplanin and susceptible to vancomycin. The selective pressure due to the use of teicoplanin in this hospital is relevant.

Staphylococcus coagulase negativos (SCoN), especialmente Staphylococcus epidermidis tem se tornado causa importante de infecções da corrente circulatória nas últimas décadas. Além disso, percentuais de resistência a meticilina entre os SCoN têm aumentado significativamente, levando ao uso de glicopeptídeos nestes pacientes. O objetivo deste estudo foi avaliar onze casos consecutivos de bacteremia clinicamente relevantes por SCoN oxacilina resistentes em um hospital localizado na cidade de São Paulo, Brasil. Cinco diferentes espécies foram identificadas por diferentes métodos fenotípicos, incluindo S. epidermidis (5), S. haemolyticus (3), S. hominis (1), S. warneri (1) e S. cohnii subsp urealyticus (1). Diferentes perfis eletroforéticos obtidos pela técnica de "Pulsed Field Gel Electrophoresis" foram observados na análise da macrorestrição do DNA nos isolados de S. epidermidis, mas dois dos três isolados de S. haemolyticus apresentaram o mesmo perfil. Esses dados indicam uma heterogeneidade nos isolados SCoN, sugerindo que a disseminação horizontal no hospital investigado não é freqüente. Um isolado de S. epidermidis e um de S. haemolyticus foram resistentes à teicoplanina e sensíveis à vancomicina. Observa-se a relevância da pressão seletiva pelo uso de teicoplanina nos pacientes deste hospital.

The recent evolution of therapeutic weapons against resistant Gram-positive microorganisms

Multiresistant Gram-positive cocci, including Staphylococcus aureus, the group of coagulase-negative staphylococci, Enterococcus faecalis and Enterococcus faecium, as well as Streptococcus pneumoniae and other streptococci, represent emerging pathogens. This issue is especially concerning in the setting of immunocompromised, hospitalized patients, in particular when surgery, invasive procedures, or prosthetic implants are carried out, patients are admitted in intensive care units, or underlying chronic disorders and immunodeficiency are of concern, and broad-spectrum antibiotics are widely used in the environment; moreover, a community spread of resistant Gram-positive cocci has been recognized during recent years. The spectrum of antimicrobials available for an effective management of these relevant infections is significantly threatened by the emerging of methicillin-resistant and more recently glycopeptide-resistant strains. The streptogramine association represented by quinupristin/dalfopristin, the oxazolidinone derivative linezolid, and the recently licensed daptomycin and tigecycline, together with a number of glycopeptides, fluoroquinolones, cephalosporins, and other experimental compounds, represent an effective response. It is due to the innovative mechanisms of action of these compounds, their maintained or enhanced activity against multiresistant pathogens, their effective pharmacokinetic/pharmacodynamic properties, their frequent possibility of synergistic activity with other compounds effective against Gram-positive pathogens, and a diffuse potential for a safe and easy administration, also to compromised patients.

Avaliação da funcionalidade do locus accessory gene regulator (agr) em cepas de Staphylococcus aureus brasileiras com sensibilidade reduzida aos glicopeptídeos / Evaluation of the functionality of the accessory gene regulator (agr) in Brazilian Staphylococcus aureus strains with reduced susceptibility to vancomycin

O tratamento de infecções por Staphylococcus aureus tem sido problemático devido ao surgimento de cepas resistentes a múltiplios antibióticos. O antibiótico de escolha para o tratamento de infecções por S. aureus resistente a oxacilina é o glicopeptídeo vancomicina. Desde o primeiro isolamento de cepas com sensibilidade reduzida a vancomicina (VISA) em 1997, tem havido crescente preocupação com a disseminação da resistência a este antibiótico. Os mecanismos moleculares que levam à resistência de baixo nível a vancomicina ainda não foram elucidados. A detecção deste fenótipo na rotina de laboratório clínico é laboriosa, pois as técnicas disponíveis são de difícil execução e interpretação. Até agora, não há relato de transmissão horizontal de infecção por VISA, e todas as cepas com este fenótipo foram isoladas de pacientes que faziam o uso prolongado de vancomicina. Uma deficiência no locus regulador de genes acessórios (agr) foi postulado como fator de risco para a aquisição do fenótipo VISA por uma cepa sensível a este antibiótico. Para este estudo, foram selecionadas 47 cepas de S. aureus, com sensibilidades variadas a vancomicina, inclusive 5 cepas VISA isoladas no Brasil. Determinou-se nas cepas as concentrações inibitórias mínimas de vancomicina e oxacilina, a atividade hemolítica em ágar sangue de carneiro e de coelho, a capacidade de aderir ao poliestireno e o polimorfismo do locus agr. Determinou-se a integridade do locus agr por PCR-RFLP e sequenciamento de bases em 13 cepas representativas das 47 estudadas. A integridade do locus regulador acessório sarA também foi avaliada por sequenciamento de bases nestas 13 cepas. Foram escolhidas 18 cepas sensíveis a vancomicina com variadas características fenotípicas e estas foram submetidas à indução de resistência a vancomicina através da passagem seriada em concentrações crescentes deste antibiótico...

Brote de infección por Enterococcus faecium resistentes a glicopéptidos en un hospital de Rosario, Argentina / Infection outbreak due to resistant Enterococcus faecium to glycopeptides in a Hospital of Rosario, Argentina

Enterococci causes serious illness in immunocompromised patients and in severely ill, hospitalized patients. They are commonly isolated from the human gastrointestinal tract, and resistance to vancomycin has increased in frequency during the past few years. We report three cases of nosocomial vancomycin resistant Entrococcus faecium (VRE) infections from September to December of 2000. A 54-year-old man presented post surgical wound infection due to VRE after 2 months of hospitalization. The second is a 65-year-old neutropenic patient with a medical history of acute myeloid leukemia and esophageal carcinoma. In this case, central venous catheter was colonized with EVR. The third, a 65-year-old woman who received therapy with ceftriaxone, ciprofloxacin and clindamicin had a urinary tract infection due to EVR. The three isolates were resistant to vancomycin (MIC value > 256 micrograms/ml). The DNA amplification pattern obtained by OD-PCR were similar in the three cases.

Production of amastigotes from metacyclic trypomastigotes of Trypanosoma cruzi

Attempts to recreate all the developmental stages of Trypanosoma cruzi in vitro have thus far been met with partial success. It is possible, for instance, to produce trypomastigotes in tissue culture and to obtain metacyclic trypomastigotes in axenic conditions. Even though T. cruzi amastigotes are known to differentiate from trypomastigotes and metacyclic trypomastigotes, it has only been possible to generate amastigotes in vitro from the tissue-culture-derived trypomastigotes. The factors and culture conditions required to trigger the transformation of metacyclic trypomastigotes into amastigotes are as yet undetermined. We show here that pre-incubation of metacyclic trypomastigotes in culture (MEMTAU) medium at 37ºC for 48 h is sufficient to commit the parasites to the transformation process. After 72 h of incubation in fresh MEMTAU medium, 90 percent of the metacyclic parasites differentiate into forms that are morphologically indistinguishable from normal amastigotes. SDS-PAGE, Western blot and PAABS analyses indicate that the transformation of axenic metacyclic trypomastigotes to amastigotes is associated with protein, glycoprotein and antigenic modifications. These data suggest that (a) T. cruzi amastigotes can be obtained axenically in large amounts from metacyclic trypomastigotes, and (b) the amastigotes thus obtained are morphological, biological and antigenically similar to intracellular amastigotes. Consequently, this experimental system may facilitate a direct, in vitro assessment of the mechanisms that enable T. cruzi metacyclic trypomastigotes to transform into amastigotes in the cells of mammalian hosts

Early and late molecular and morphologic changes that occur during the in vitro transformation of Trpanosoma cruzi metacyclic trypomastigotes to amastigotes

The amastigogenesis primary of T. cruzi occurs naturally when metacyclic trypomastigotes transform into amastigotes within the cells of the mammalian host. The in vitro study of the macromolecular changes that occur over several days during the transformation process should provide significant indications of how the parasite adapts to the mammalian host environment. We show here that metacyclic trypomastigotes pre-incubated at 37 degrees C in a protein-rich medium reach a high degree of transformation to amastigotes when re-incubated in the fresh medium. Giemsa-stained smears show that during the pre-incubation phase, the metacyclic trypomastigotes undergo lengthening at the posterior end and a thinning out of the entire body. SDS-PAGE analysis of polypeptides and glycopeptides or Western blot with stage-specific antisera analyses indicate that the in vitro primary amastigogenesis is associated with abrupt changes in protein, glycoprotein, and stage-specific antigens that occur simultaneously during the first 24 hours of pre-incubation. Since the differentiating system consists of a rich media at 37 degrees C, temperature and medium constitution must trigger a macromolecular differentiation to amastigotes that precedes the morphological transformation by several days. This transformation is associated with the rearrangement of stage-specific antigens and takes place when the culture medium is changed.

Caracterização de cepas de Staphylococcus aureus resistentes à vancomicina isoladas no Brasil / Staphylococcus aureus strains resistant to vancomycin characterization isolated in Brazil

O isolamento de cepas de Staphylococcus aureus resistente à vancomicina (VRSA) de amostras clínicas foi rekatado no Japão, França, Estados Unidos e Coréia, mas ainda não havia sido relatado no Brasil. O objetivo deste estudo foi avaliar a possível presença de cepas hetero-VRSA ou VRSA em 05 hospitais públicos da cidade de São Paulo. No total, foram triadas 469 cepas de S aureus resistentes à oxacilina (ORSA), das quais 198 foram isoladas no Hospital Geral de Vila Penteado (HGVP), 137 no Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HCFMUSP), 50 no Hospital AC Camargo, 48 no Hospital Emílio Ribas e 36 no Hospital Universitário da USP. A triagem das cepas hetero-VRSA e VRSA foi realizada...

Glycopeptides susceptibility among enterococci isolated from a poultry farm in São Paulo, Brazil (1996/1997)

Entrococci resistance to glycopeptides was evaluated in Brazilian poultry feed with feed supplemented with avoparcin as growth promoter. The susceptibility to the glycopeptides avoparcin, teicoplanin and vancomycin was determined for 217 enterococci isolated from cloacal swabes (one swab per bird) in tests and controls groups. Tests group comprised three groups (A, B and C) of Hubbard broiler-chickens 14, 21 and 35 days old, respectively. These birds were from one single farm, with a common feed source supplemented with avoparcin (10 mg/kg of feed). Controls groups (1 and 2) comprised 25 and 42 days old broilers, respectively, obtained from the faculty of Veterinary Medicine's aviary (University of São Paulo) where avoparcin was never used. No glycopeptide resistant enterococci strain was found, but and increase of Enterococcus faecium in faeces of chickens fed with avoparcin, independent of the age of the bird, was detected.

Avaliação do perfil de suscetibilidade a antibióticos em amostras de enterococos de origem aviária em São Paulo / Evaluation of antimicrobial agents susceptibility patterns among enterococcusmsp. from poultry in São Paulo

O uso de antibióticos glicopeptídeos na área de produção animal como promotor de crescimento pode elevar os números de microrganismos resistentes a antimicrobianos nos animais tratados. Trabalhos europeus correlacionam a presença de enterococs resistentes a vancomicína com o uso do avoparcina, um antibiótico glicopeptídeo seme@te quimicamente à vancomicina, como promotor de crescimento. Os enterococos resistentes podem ser transn-útídos aos llumanos através de contato com fazendas de animais e através do ambiente. Enterococos resistentes à vancomina começam a ser isolados no Brasil. Para avaliar os padrões de suscetibilidade a agentes antimicrobianos de enterococos isolados de aviários em São Paulo, iniciamos um estudo pesquisando enterococos resistentes a vancomicina em aves alimentadas com ração contendo ou não avoparcina como promotor de crescimento e em alimento a base de carne de frango. As amostras coletadas de diferentes fontes (swab cloacal em frangos de corte para obtenção de material fecal, swab interno de carcaças, swab de medula óssea em recortes de frango, amostras de "cama de frango") foranl transportadas para o laboratório em O,7 por cento ágar nutriente e repicadas em ágar sangue de carneiro a 5 por cento acrescido de 300 U/ml de Polimixina B, como meio seletivo. A identificação dos enterococos foi realizada através do método de FACKLAM & SAHM (l995). Testes de suscetibihdade a avoparcina, vanconúcina e teicoplaninaforain determinados através de método de diluição de ágar de acordo com o NCCLS. Foram examinados quatro grupos de amostras: grupo controle (frangos alimentados com ração não suplementada com avoparcina), carne de frango (recortes e carcaças inteiras), grupo Teste (frangos alimentados com ração contendo avoparcina) e "cama de frango" reut@da várias vezes (aproximadamente por 6 gerações de frango alimentados com ração contendo avoparcina). Um total de 234 enterococos foram isolados de 286 amostras. Todos os enterococos isolados das aves, recortes e carcaças foram susceptíveis aos glicopeptídeos examinados, porém houve alteração da microbiota do grupo teste, com prevalência de E. faecium (52,9 por cento ). Detectou-se altos níveis de resistência a aminoglicosídeos entre as amostras isoladas nos grupos Teste. Uma vez que microrganismos resistentes podem estar relacionados ao uso de antimicrobianos na área veterinária, um programa de controle é justificado