Chronic periodontitis is a multifactorial infectious disease associated with Gram-negative strict anaerobes which are immersed in the subgingival biofilm. Porphyromonas gingivalis, an important periodontal pathogen, is frequently detected in patients with chronic periodontitis. Although isolates of P. gingivalis tend to be susceptible to most antimicrobial agents, relatively little information is available on its in vitro antimicrobial susceptibility. The aim of this study was to determine the frequency of P. gingivalis in patients with chronic periodontitis and to assess antimicrobial susceptibility in terms of minimum inhibitory concentration (MIC) of clinical isolates to metronidazole and tetracycline. A descriptive, observational study was performed including 87 patients with chronic periodontitis. Samples were taken from the periodontal pocket using paper points, which were placed in thioglycollate broth. Samples were incubated for 4 hours at 37°C in anaerobic conditions and finally replated on Wilkins-Chalgren anaerobic agar (Oxoid). Bacteria were identified using the RapIDTMANAII system (Remel) and antimicrobial susceptibility was determined with the M.I.C. Evaluator test (MICE, Oxoid). P. gingivalis was identified in 30 of the 87 patients with chronic periodontitis, which represents a frequency of 34.5%. All 30 isolates (100%) were sensitive to metronidazole, with MIC values ranging from 0015-4ug/ml. Regarding tetracycline, 27 isolates (90%) were sensitive, with MIC values ranging from <0.015 to 4 ug /ml, the remaining three isolates (10%) were resistant to tetracycline with MIC values of 8ug/ ml. There was no statistically significant difference in age, gender, pocket depth, clinical attachment level and severity of periodontitis between the group of patients with chronic periodontitis and P. gingivalis and the group of patients with chronic periodontitis without P. gingivalis. In conclusion, P. gingivalis was found at a frequency of 34.5% in patients with chronic periodontitis and clinical isolates were highly sensitive to metronidazole and tetracycline.

La periodontitis cronica es una enfermedad infecciosa multifactorial asociada a bacilos Gram-negativos anaerobicos estrictos que se encuentran inmersos en la biopelicula subgingival. Porphyromonas gingivalis, importante patogeno periodontal, es fre - cuentemente detectado en pacientes con periodontitis cronica. Los aislamientos clinicos de P. gingivalis tienden a ser susceptibles a la mayoria de agentes antimicrobianos; sin embargo, se tiene poca informacion sobre la susceptibilidad antimicrobiana in vitro. El objetivo de este estudio fue determinar la frecuencia de P. gingivalis en pacientes con periodontitis cronica y determinar la susceptibilidad antimicrobiana en terminos de concentracion inhibitoria minima (CIM) de los aislamientos clinicos a metronidazol y tetraciclina. Se realizo un estudio observacional descriptivo en el que se incluyeron 87 pacientes con periodontitis cronica. Las muestras tomadas con conos de papel de la bolsa periodontal se depositaron en caldo tioglicolato, se incubaron durante 4 horas a 37 oC en anaerobiosis y se resembraron en agar anaerobico Wilkins- Chalgren (Oxoid). La identitficacion de los aislamientos se realizo con el sistema RapIDTM ANA II (Remel) y la susceptibilidad antibiotica para metronidazol y tetraciclina se evaluo mediante la tecnica M.I.C.Evaluator (M.I.C.E., Oxoid). En 30 de los 87 pacientes con periodontitis cronica se identifico P. gingivalis, lo que representa una frecuencia de 34.5%. Todos los 30 aislamientos (100%) fueron sensibles al metronidazol con valores de CIM desde 0.015 hasta 4 ug/ml. En cuanto a tetraciclina, 27 aislamientos (90%) fueron sensibles con valores de CIM desde <0.015 hasta 4 ug/ml; los restantes 3 aislamientos (10%) fueron resistentes a tetraciclina con valores de CIM de 8 ug/ml. En cuanto a edad, genero, profundidad de bolsa, nivel de insercion clinico y severidad de la periodontitis no se presentaron diferencias estadisticamente significativas entre el grupo de pacientes con periodontitis cronica y P. gingivalis y el grupo de pacientes con periodontitis cronica sin P. gingivalis. En conclusion, P. gingivalis se encontro en una frecuencia de 34.5% en pacientes con periodontitis cronica y los aislamientos clinicos fueron altamente sensibles a metronidazol y tetraciclina.

Snake venoms are rich sources of active proteins that have been employed in the diagnosis and treatment of health disorders and antivenom therapy. Developing countries demand fast economical downstream processes for the purification of this biomolecule type without requiring sophisticated equipment. We developed an alternative, simple and easy to scale-up method, able to purify simultaneously protease and phospholipase A2 toxins from Bothrops alternatus venom. It comprises a multiple-step partition procedure with polyethylene-glycol/phosphate aqueous two-phase systems followed by a gel filtration chromatographic step. Two single bands in SDS-polyacrylamide gel electrophoresis and increased proteolytic and phospholipase A2 specific activities evidence the homogeneity of the isolated proteins.

Cross-neutralization of Crotalus durissus terrificus venom coagulant activity was tested using bivalent horse antivenom against Bothrops alternatus and Bothrops diporus venoms. Our in vitro and in vivo experiments showed that bothropic antivenom neutralizes the thrombin-like activity of crotalic snake venom and this cross-reaction was demonstrated by immunoassays either with whole venom or a purified thrombin-like enzyme. These results suggest common antigenic properties and, consequently, similar molecular structure among venom thrombin-like enzymes. Besides, they provide information that could be further used in the development of new antivenom formulations.