Molecular detection of tick-borne bacterial agents in Brazilian and exotic captive carnivores

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Piperamides and their derivatives as potential anti-trypanosomal agents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Propolis: anti-Staphylococcus aureus activity and synergism with antimicrobial drugs

Propolis is a natural resinous substance collected by bees from tree exudates and secretions. Its antimicrobial activity has been investigated and inhibitory action on Staphylococcus aureus growth was evaluated The in vitro synergism between ethanolic extract of propolis (EEP) and antimicrobial drugs by two susceptibility tests (Kirby and Bauer and E-Test) on 25 S. aureus strains was evaluated Petri dishes with sub-inhibitory concentrations of EEP were incubated with 13 drugs using Kirby and Bauer method and synergism between EEP and five drugs [choramphenicol (CLO), gentamicin (GEN), netilmicin (NET), tetracycline (TET), and vancomycin (VAN)] was observed. Nine drugs were assayed by the E-test method and five of them exhibited a synergism [CLO, GEN, NET, TET, and clindamycin (CLI)]. The results demonstrated the synergism between EEP and antimicrobial drugs, especially those agents that interfere on bacterial protein synthesis.

Natural chromenes and chromene derivatives as potential anti-trypanosomal agents

The aim of the study was to investigate the anti-trypanocidal activities of natural chromene and chromene derivatives. Five chromenes were isolated from Piper gaudichaudianum and P. aduncum, and a further seven derivatives were prepared using standard reduction, methylation and acetylation procedures. These compounds were assayed in vitro against epimastigote forms of Trypanosoma cruzi, the causative agent of Chagas disease. The results showed that the most of the compounds, especially those possessing electron-donating groups as substituents on the aromatic ring, showed potent trypanocidal activity. The most active compound, [(2S)-methyl-2-methyl-8-(3″-methylbut-2″-enyl)-2- (4′-methylpent-3′-enyl)-2H-chromene-6-carboxylate], was almost four times more potent than benznidazole (the positive control) and showed an IC 50 of 2.82 μM. The results reveal that chromenes exhibit significant anti-trypanocidal activities and indicate that this class of natural product should be considered further in the development of new and more potent drugs for use in the treatment of Chagas disease. © 2008 Pharmaceutical Society of Japan.

Hydroxyquinoline derived vanadium(IV and V) and copper(II) complexes as potential anti-tuberculosis and anti-tumor agents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Antibiotic treatment schemes for very severe community-acquired pneumonia in children: a randomized clinical study

Objective. To compare clinical response to initial empiric treatment with oxacillin plus ceftriaxone and amoxicillin plus clavulanic acid in hospitalized children diagnosed with very severe community-acquired pneumonia (CAP).Methods. A prospective randomized clinical study was conducted among children 2 months to 5 years old with a diagnosis of very severe CAP in the pediatric ward of São Paulo State University Hospital in Botucatu, São Paulo, Brazil, from April 2007 to May 2008. Patients were randomly divided into two groups by type of treatment: an oxacillin/ceftriaxone group (OCG, n = 48) and an amoxicillin/clavulanic acid group (ACG, n = 56). Analyzed outcomes were: time to clinical improvement (fever and tachypnea), time on oxygen therapy, length of stay in hospital, need to widen antimicrobial spectrum, and complications (including pleural effusion).Results. The two groups did not differ statistically for age, sex, symptom duration before admission, or previous antibiotic treatment. Time to improve tachypnea was less among ACG patients than OCG patients (4.8 +/- 2.2 versus 5.8 +/- 2.4 days respectively; P = 0.028), as was length of hospital stay (11.0 +/- 6.2 versus 14.4 +/- 4.5 days respectively; P = 0.002). There were no statistically significant differences between the two groups for fever improvement time, time on oxygen therapy, need to widen antimicrobial spectrum, or frequency of pleural effusion.Conclusions. Both treatment plans are effective in treating very severe CAP in 2-monthto 5-year-old hospitalized children. The only analyzed outcome that favored amoxicillin/clavulanic acid treatment was time required to improve tachypnea.

Antimicrobial resistance of aerobes and facultative anaerobes isolated from the oral cavity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of tunicamycin on glycoprotein antigens of Aspergillus fumigatus

Tunicamycin, which inhibits N-glycosylation of proteins, was used as a tool to determine the type of linkage which occurs in glycoprotein antigens of Aspergillus fumigatus. When A. fumigatus extracts were electrophoretically separated and blotted then probed with anti-Aspergillus patients' sera, differences in antigenic profiles were noted when tunicamycin-treated samples were compared with controls. Tunicamycin had no detectable effect on the cellular proteinases of A. fumigatus, most of which are glycosylated. Some enzymatic components were lacking when extracellular proteinases were compared with those of control samples. The major catalase component of A. fumigatus is a concanavalin A (Con A)-binding glycoprotein. In cultures grown in the presence of tunicamycin, partiallydeglycosylated catalase components were obtained which could be distinguished from the native catalase by their altered mobilities in polyacrylamide gels. The effect of deglycosylation on catalase antigens was monitored using an antiserum raised to a ConA-binding fraction of A fumigatus mycelium. These antibodies bound both to the native glycoprotein and the partially deglycosylated material. These latter two were largely unaffected when incubated with an antiserum raised to a non-ConA-binding fraction of A. fumigatus which is essentially carbohydrate free. The ability to produce partially-glycosylated antigens of A. fumigatus offers a model to study the effect of basic structural modifications on both the enzymatic and antigenic activities of these molecules.

Calcium hydroxide and a corticosteroid-antibiotic association as dressings in cases of biopulpectomy. A comparative study in dogs' teeth.

The subject of this paper was to study the behavior of the periapical tissues of dogs' teeth after biopulpectomy and dressing with calcium hydroxide or a corticosteroid-antibiotic association, before root canal filling with zinc oxide eugenol (ZOE) or Sealapex sealers. The teeth were overinstrumented and dressed for 7 days before the root canal filling. The animals were sacrificed 180 days after treatment and the specimens were prepared for morphological analysis. Specimens treated with Sealapex presented a higher number of cases with biological closure than ZOE. When the root canals were filled with ZOE, better results were observed with the use of the Ca(OH)2 dressing.

Phytochemical evidence for the plant origin of Brazilian propolis from Sao Paulo state

Propolis and plant secretions from three species, most frequently mentioned as botanical sources of the bee glue in Brazil (Baccharis dracunculifolia, Araucaria angustifolia and Eucalyptus citriodora) have been investigated using GC-MS. Based on chemical evidence, B. dracunculifolia was shown to be the main propolis source in Sao Paulo state. The antibacterial and antifungal activities of all four materials were also tested, the most active being propolis and Baccharis leaf exudate.

Influence of antimicrobial subinhibitory concentrations on hemolytic activity and bacteriocin-like substances in oral: Fusobacterium nucleatum

Fusobacterium nucleatum is considered for its role in colonization of initial and late microorganisms in dental plaque and for its coaggregation with other bacterial species. It is known that action of different antimicrobial substances may interfere with either virulence factors or with host-bacteria interaction. The goal of this study was to examine the influence of subinhibitory concentrations of chlorhexidine, triclosan , penicillin G and metronidazole on hemolytic activity and bacteriocin-like substance production of oral F. nucleatum. A high resistance to penicillin G was observed and 63% of the isolates were β-lactamase positive. All the tested isolates were susceptible to metronidazole. F. nucleatum isolates grown with or without antimicrobials were alpha-hemolytics. Bacteriocin-like substance production was increased in isolates grown with penicillin G. Impaired production of hemolytic or antagonic substances can suggest a role in the regulation of oral microbiota.

nor-Lignans from the leaves of Styrax ferrugineus (Styracaceae) with antibacterial and antifungal activity

Chemical examination of the leaves of Styrax ferrugineus yielded 5-[3'-(β-D-glucopyranosyloxy)propyl]-7-methoxy-2-(3',4'-dime-thoxyphenyl) benzofuran, along with the known nor-lignans 5-(3'-hydroxypropyl)-7-methoxy-2-(3',4'-methylenedioxyphenyl) benzofuran, 5-(3'-hydroxypropyl)-7-methoxy-2-(3',4'-dimethoxyphenyl)benzofuran, 5-[3'-(β-D-glucopyranosyloxy)propyl]-7-methoxy-2-(3', 4'-methylenedioxyphenyl)benzofuran and the lignan, dihydrodehydrodiconiferyl alcohol. All arylpropanoids isolated showed antibacterial and antifungal activities. The structures of the isolates were established by spectroscopic analysis. (C) 2000 Elsevier Science Ltd.

Antibacterial activity of a stearic acid derivative from Stemodia foliosa

From the hexane-soluble fraction of an ethanol extract from leaves and stems of Stemodia foliosa (Scrophulariaceae), the new stearic acid 4-[(n-pentoxy)phenethyl] ester (1) was isolated. This compound exhibited antibacterial properties at 10μg/mL concentration by using disc diffusion method against Gram-positive bacteria Bacillus cereus and Bacillus subtilis and fast-acid bacterium Mycobacterium fortuitum. The structure of the new compound was elucidated by spectroscopic methods and by chemical conversion.