Minimal inhibitory concentration of azithromycin in Rhodococcus equi strains isolated from foals

O perfil de sensibilidade microbiana e a concentração inibitória mínima (MIC) da azitromicina para 42 cepas de Rhodococcus equi isoladas de potros, no Brasil, e em uma cepa-controle, foi avaliado, respectivamente, pelos métodos de difusão com discos e E-test. A azitromicina apresentou 100% de efetividade in vitro para todas as cepas em ambos os testes. As cepas de R. equi apresentaram MIC90 para azitromicina em valores <1.5µg/ml. Este estudo mostra a alta efetividade da azitromicina em linhagens de R. equi isoladas no Brasil, sugerindo o uso dessa droga como alternativa na terapia da rodococose em potros.

Prevalence of virulence factors in Escherichia coli strains isolated from the genital tract of healthy cows

Determinou-se a prevalência dos genes de virulência expressando fimbrias, produção de hemolisina, colicina e aerobactina em cepas de Escherichia coli obtidas do trato genital de vacas saudáveis que não apresentam sinais clínicos indicativos de infecção. A presença dos genes responsáveis pela expressão de fimbrias (pap, sfa, afa) foi avaliada através de reação em cadeia da polimerase utilizando primers especificos para cada um dos genes, nenhum deles foi detectado em qualquer uma das cepas isoladas. A prevalência dos fatores de virulência foi de 90,4%, 69,8%, 28,5% para colicina, hemolisina e aerobactina, respectivamente. A análise da patogenicidade das cepas do trato genital pode contribuir para o entendimento do comportamento das cepas de E. coli.

Antimicrobial susceptibility of coagulase-negative Staphylococci isolated from mastitic cattle in Brazil

Um total de 109 cepas de Staphylococci coagulase-negativa foi isolado de leite de vacas com mastite clínica e subclínica, em 35 fazendas, situadas em nove estados brasileiros, no período de fevereiro a maio de 2005. Os isolados foram investigados em relação a susceptibilidade in vitro a diversos agentes antimicrobianos. A resistência à penicilina foi a observação mais freqüente (93,5%), seguida por sulfonamida (88,9%), novobiocina (88,6%) e ampicilina (85,3%). Todas as cepas examinadas mostraram resistência a pelo menos uma das drogas antimicrobianas testadas. Cepas apresentando resistência múltipla foram extremamente comuns, com 10,0% dos microrganismos isolados apresentando resistência a todas as drogas antimicrobianas. Os resultados obtidos indicaram que as cepas de Staphylococci coagulase-negativas, isoladas no Brasil, apresentaram um alto grau de resistência a antimicrobianos. Estes resultados são, provavelmente, uma conseqüência da pressão devida ao uso intensivo de drogas antimicrobianas.

Paracoccidioides brasiliensis: a mycologic and immunochemical study of a sample isolated from an armadillo (Dasipus novencinctus)

Amostra de Paracoccidioides brasiliensis isolada de vísceras (baço e fígado) de um tatu (Dasipus novencinctus) foi estudada do ponto de vista micológico e imunoquímico. O tatu havia sido capturado em área da usina hidroelétrica de Tucuruí (Estado do Pará). Este já havia sido considerado como reservatório enzoótico do Paracoccidioides brasiliensis naquela região. Esta amostra, conservada na Micoteca do Instituto de Medicina Tropical de São Paulo sob o número 135, apresenta todas as características de Paracoccidioides brasiliensis, com elevado poder antigênico e baixa virulência para cobaios e ratos Wistar. A demonstração do exo-antígeno específico do P. brasiliensis, representado pela glicoproteína de peso molecular 43 kDa, foi evidente através das técnicas de Imunodifusão Dupla, Imunoeletroforese, SDS-PAGE e Imunoblotting.

Antigenic typing of brazilian rabies virus samples isolated from animals and humans, 1989-2000

Amostras de vírus rábico isoladas de animais e humanos no período de 1989 a 2000 foram tipificadas antigenicamente com a utilização de um painel de anticorpos monoclonais contra a nucleoproteína viral, pré-estabelecido para o estudo da epidemiologia molecular do vírus rábico isolado nas Américas. As amostras testadas foram isoladas no laboratório de diagnóstico do Instituto Pasteur e outros centros de diagnóstico de raiva no Brasil. Além das cepas de vírus rábico fixo CVS-31/96-IP, mantida em cérebro de camundongos e a PV-BHK/97, mantida em cultura de células, cepas de vírus rábico isoladas de cães, gatos, bovinos, eqüinos, morcegos, ovinos, caprino, suínos, raposa, sagüí, coatí, guaxinim e humanos, totalizaram 330 amostras. Seis variantes antigênicas foram definidas, compatíveis com perfís observados no painel de anticorpos monoclonais pré-estabelecido utilizado, as de número 2 (cão), 3 (Desmodus rotundus), 4 (Tadarida brasiliensis), 5 (Vampiro da Venezuela), 6 (Lasiurus cinereus) e Lab (reagente a todos os anticorpos utilizados), além de outros seis perfís desconhecidos, não compatíveis com aqueles observados no painel utilizado. A maior variabilidade foi observada entre as amostras isoladas de morcegos insetívoros e a variante mais comum isolada entre as espécies foi a variante 3 (Desmodus rotundus). Estes fatos podem representar a existência de múltiplos ciclos de transmissão independentes, envolvendo diferentes espécies de morcegos.

Production of bacteriocin-like inhibitory substances (BLIS) by Streptococcus salivarius strains isolated from the tongue and throat of children with and without sore throat

Cepas de Streptococcus salivarius, isoladas de crianças com e sem dor de garganta, foram testadas quanto à produção de bacteriocina contra Streptococcus pyogenes. Os resultados mostraram que as crianças que não tinham dor de garganta possuiam, na boca, cepas de bactérias produtoras de substâncias inibidoras semelhantes à bacteriocina contra S. pyogenes.

Genetic and phylogenetic analysis of glycoprotein of rabies virus isolated from several species in Brazil

Genetic and phylogenetic analyses of the region containing the glycoprotein (G) gene, which is related to pathogenicity and antigenicity, and the G-L intergenic region were carried out in 14 Brazilian rabies virus isolates. The isolates were classified as dog-related rabies virus (DRRV) or vampire bat-related rabies virus (VRRV), by nucleoprotein (N) analysis. The nucleotide and amino acid (AA) homologies of the area containing the G protein gene and G-L intergenic region were generally lower than those of the ectodomain. In both regions, nucleotide and deduced AA homologies were lower among VRRVs than among DRRVs. There were AA differences between DRRV and VRRV at 3 antigenic sites and epitopes (IIa, WB+ and III), suggesting that DRRV and VRRV can be distinguished by differences of antigenicity. In a comparison of phylogenetic trees between the ectodomain and the area containing the G protein gene and G-L intergenic region, the branching patterns of the chiropteran and carnivoran rabies virus groups differed, whereas there were clear similarities in patterns within the DRRV and VRRV groups. Additionally, the VRRV isolates were more closely related to chiropteran strains isolated from Latin America than to Brazilian DRRV. These results indicate that Brazilian rabies virus isolates can be classified as DRRV or VRRV by analysis of the G gene and the G-L intergenic region, as well as by N gene analysis.

beta(2)-Agonists and cAMP inhibit protein degradation in isolated chick (Gallus domesticus) skeletal muscle

1. The role of beta(2)-agonist and of cAMP in chick skeletal muscle proteolytic pathways and protein synthesis was investigated using an in vitro preparation that maintains tissue glycogen stores and metabolic activity for several hours.2. In extensor digitorum longus (EDL) muscle total proteolysis decreased by 15 to 20% in the presence of equimolar concentrations of epinephrine, clenbuterol, a selective beta(2)-agonist, or dibutyryl-cAMP. Rates of protein synthesis were not altered by clenbuterol or dibutyryl-cAMP.3. The decrease in the rate of total protein degradation induced by 10(-5) M clenbuterol was paralleled by a 44% reduction in Ca2+-dependent proteolysis, which was prevented by 10(-5) M ICI 118.551, a selective beta(2)-antagonist.4. No change was observed in the activity of the lysosomal, ATP-dependent, and ATP-independent proteolytic systems. Ca2+-dependent proteolytic activity was also reduced by 58% in the presence of 10(-4) M dibutyryl-cAMP or isobutylmethylxanthine.5. The data suggest that catecholamines exert an inhibitory control of Ca2+-dependent proteolysis in chick skeletal muscle, probably mediated by beta(2)-adrenoceptors, with the participation of a cAMP-dependent pathway.

FUNCTIONAL AND ULTRASTRUCTURAL EVALUATION OF MYOCARDIAL PROTECTION PROVIDED BY INTERMITTENT CORONARY SINUS PERFUSION IN THE ISOLATED DOG HEART

1. The protection offered by intermittent perfusion of of cardioplegic solution through the coronary sinus was investigated in isovolumic blood-perfused dog heart preparations submitted to 60 min of ischemia and 45 min of reperfusion.2. The preparations were divided into three treatment groups: a) coronary sinus, consisting of preparations (N = 10) perfused through the coronary sinus under 40 cm water pressure; b) aortic, consisting of preparations (N = 10) perfused through the aortic stump under 100 mmHg pressure; c) control, consisting of hearts (N = 9) that were not perfused with cardioplegic solution.3. Properties of contractile capacity and relaxation were markedly impaired in the control group but were preserved to a comparable extent in the groups perfused with cardioplegic solution through the aorta and coronary sinus. Developed pressure decreased in the control group (before ischemia: 70 +/- 5.5 mmHg; after reperfusion: 35 +/- 12 mmHg; P < 0.05) and didn't vary in the aortic group (from 69 +/- 4 mmHg to 65 +/- 13 mmHg; P > 0.05) and coronary sinus group (from 69 +/- 4.6 mmHg to 60 +/- 10 mmHg; P > 0.05). Myocardial relaxation was evaluated by the +/- dp/dt ratio. In the control group there was impairment of myocardial relaxation as indicated by an increase of this index after reperfusion (from 1.05 +/- 0.05 to 1.46 +/- 0.23; P < 0.05), whereas in the aortic (from 1.10 +/- 0.13 to 1.15 +/- 0.20; P > 0.05) and the coronary sinus (from 1.03 +/- 0.14 to 1.08 +/- 0.16; P > 0.05) groups there was no variation. Ultrastructural changes in the myocardium were negligible in all three groups at the end of reperfusion.4. We conclude that intermittent perfusion of a hypothermic cardioplegic solution through the coronary sinus is effective for the protection of the myocardium during total ischemia.

Crystallization of bothropstoxin II isolated from the venom of Bothrops jararacussu

A myotoxic phospholipase A(2), bothropstoxin II, which exhibits low hydrolytic activity, was crystallized and X-ray diffraction data were collected to a resolution of 2.2 Angstrom. Preliminary analysis reveals the presence of three molecules in the asymmetric unit. Copyright (C) 1996 Elsevier B.V. Ltd.

Antigenic similarities to Paracoccidioides brasiliensis in thermo-dependent dimorphic fungi isolated from soil in Botucatu, SP, Brazil

We compared the antigenic characteristics of two thermo-dependent dimorphic fungi isolated from soil in Botucatu, an endemic area of paracoccidioidomycosis (PCM) and Paracoccidioides brasiliensis. The soil isolates grew as cerebriform colonies at 37 degrees C (yeast form) and as cottonous colonies at 25 degrees C (mycelial form). No pathogenicity for ddY mice or hamsters were observed. In immunodiffusion test, there were precipitation bands between the 2 soil isolates and pooled PCM patient sera. There were also common precipitation bands at 21, 50 and 58 kDa between the soil isolates antigens and PCM patient sera by Western-blotting, but no gp43 kDa band. No gene for gp43 kDa protein was detected in the soil isolates by PCR. The fact that these isolates were obtained from an endemic area of PCM and there were some antigenic similarities between the soil isolates and P. brasiliensis in immunodiffusion test and Western-blotting may have some importance in epidemiological surveys done with paracoccidioidin as well interfering with the immune response of the exposed population.

Chemosystematic studies of natural compounds isolated from Asteraceae: characterization of tribes by principal component analysis

This work describes an application of principal component analysis (PCA) on a database of secondary metabolites from the Asteraceae family. The numbers of occurrences of metabolites in 11 chemical classes for the different vibes of the family were used as variables, PCA allows the identification of chemical classes that contribute most to the subgroups classification within the family. Relationships between chemical composition and botanical classification were made. (C) 2001 Elsevier B.V. B.V. All rights reserved.

Comparative ''in vitro'' study on the susceptibility and emergence of mutants resistant to danofloxacin and ciprofloxacin among Staphylococcus aureus isolated from bovine mastitis

The antimicrobial susceptibility of danofloxacin was compared in vitro with ciprofloxacin against mastitogenic Staphylococcus aureus. Danofloxacin was more active than ciprofloxacin, showing minimal inhibitory concentrations (MIC90), minimal bactericidal concentrations (MBC90) and MBC/MIC ratio lower than those of ciprofloxacin. Ciprofloxacin-resistant mutants occurred at higher frequencies (greater than or equal to 10(-6)) than for danofloxacin (10(-9)).