Perfil de susceptibilidade a antimicrobianos de bactérias isoladas em diferentes sistemas de cultivo de tilápia-do-nilo (Oreochromis niloticus) Profile of antimicrobial resistance in bacterial populations recovered from different Nile tilapia (Oreochromis niloticus) culture systems

Caracterizaram-se as populações bacterianas isoladas de três sistemas de cultivo de tilápias, sem utilização prévia de antimicrobianos. No sistema 1 usou-se tanque de alvenaria com arraçoamento, no sistema 2, tanque de terra com arraçoamento e no sistema 3, tanque de terra com adubação orgânica. Posteriormente, foi verificado o perfil qualitativo de resistência a antimicrobianos de 98 amostras bacterianas. Membros da família Vibrionaceae predominaram nos três sistemas analisados. Observou-se elevado número de bactérias resistentes principalmente à ampicilina e à eritromicina. Bactérias resistentes à norfloxacina e à gentamicina não foram freqüentes e cerca de 50% das amostras dos isolados bacterianos foram resistentes à tetraciclina. Dentre as amostras testadas, 96% apresentaram resistência simultânea a dois ou mais antimicrobianos (MAR>0,2). O índice MAR médio para os três sistemas de criação foi 0,4, e foram mesmo considerados fontes de risco para disseminação de bactérias resistentes.Bacterial populations from different tilapia culture system with no antimicrobial use were characterized. Concret pond and commercial feed, land pond and commercial feed, and land pond and animal manure were used in systems I, II and III, respectively. Ninety-eight bacterial strains were subjected to sensitivity testing. Members of Vibrionaceae were the most prevalent in all systems analysed. The most bacterial strains were resistant to ampicillin and erithromicin, but resistance to norfloxacin and gentamicin were uncommon. A half to bacterial isolates was resistant to tetracycline. From the 98 bacterial isolates, 96% were resistant to two or more antimicrobials. The multiple antimicrobial resistance index was determined and it was similar for all systems analyzed (Mar= 0.4), indicating a high risk source for multiple antibiotic resistance

Biological And Structural Characterization Of A New Pla 2 From The Crotalus Durissus Collilineatus Venom

In the present article we report on the biological characterization and amino acid sequence of a new basic Phospholipases A 2 (PLA 2) isolated from the Crotalus durissus collilineatus venom (Cdcolli F6), which showed the presence of 122 amino acid residues with a pI value of 8.3, molecular mass of 14 kDa and revealed an amino acid sequence identity of 80 with crotalic PLA 2s such as Mojave B, Cdt F15, and CROATOX. This homology, however, dropped to 50 if compared to other sources of PLA 2s such as from the Bothrops snake venom. Also, this PLA 2 induced myonecrosis, although this effect was lower than that of BthTx-I or whole crotoxin and it was able to induce a strong blockage effect on the chick biventer neuromuscular preparation, independently of the presence of the acid subunid (crotapotin). The neurotoxic effect was strongly reduced by pre-incubation with heparin or with anhydrous acetic acid and q-BPB showed a similar reduction. The q-BPB did not reduce significantly the myotoxic activity induced by the PLA 2, but the anhydrous acetic acid treatment and the pre-incu-bation of PLA 2 with heparin reduced significantly its effects. This protein showed a strong antimicrobial activity against Xanthomonas axonopodis passiflorae (Gram-negative), which was drastically reduced by incubation of this PLA 2 with q-BPB, but this effect was marginally reduced after treatment with anhydrous acetic acid. Our findings here allow to speculate that basic amino acid residues on the C-terminal and molecular regions near catalytic site regions such as Calcium binding loop or b-wing region may be involved in the binding of this PLA 2 to the molecular receptor to induce the neurotoxic effect. The bactericidal effect, however, was completely dependent on the enzymatic activity of this protein. © 2005 Springer Science+Business Media, Inc.242103112Aguiar, A.S., Alves, C.R., Melgarejo, A., Giovanni-De-Simone, S., (1996) Toxicon, 34, pp. 555-565Babu, A.S., Gowda, T.V., (1994) Toxicon, 32, pp. 749-752Bon, C., Changeux, J.P., Jeng, T.W., Fraenkel-Conrat, H., (1979) Eur. J. Biochem., 99, pp. 471-481Breithaupt, H., (1976) Toxicon, 14, pp. 221-233Condrea, E., Fletcher, J.E., Rapuano, B.E., Yang, C.C., Rosenberg, P., (1981) Toxicon, 19, pp. 705-720Dennis, E.A., (1997) Trends Biochem. Sci., 22, pp. 1-12Faure, G., Bon, C., (1988) Biochemistry, 27, pp. 730-738Fuentes, L., Hernandez, M., Nieto, M.L., Sanchez-Crespo, M., (2002) FEBS Lett., 531, pp. 7-11Gowda, T.V., Middlebrook, J.L., (1994) Toxicon, 32, pp. 955-964Habermann, E., Breithaupt, H., (1978) Toxicon, 16, pp. 19-30Holzer, M., MacKessy, S.P., (1996) Toxicon, 34, pp. 1149-1155Kudo, I., Murakami, M., (2002) Prostag. Oth. Lipid Mediat., 68, pp. 3-58. , 69Lambeau, G., Lazdunski, M., (1999) TIPS, 20, pp. 162-170Landucci, E.C., Condino-Neto, A., Perez, A.C., Hyslop, S., Corrado, A.P., Novello, J.C., Marangoni, S., Denucci, G., (1994) Toxicon, 32, pp. 217-226Lomonte, B., Angulo, Y., Calderon, L., (2003) Toxicon, 42, pp. 885-901Murakami, M., Kudo, I., (2002) J. Biochem (Tokyo), 131, pp. 285-292Oliveira, D.G., Toyama, M.H., Novello, J.C., Beriam, L.O., Marangoni, S., (2002) J. Protein Chem, 21, pp. 161-168Prijatelj, P., Sribar, J., Ivanovski, G., Krizaj, I., Gubensek, F., Pungercar, J., (2003) Eur. J. Biochem., 270, pp. 3018-3025Schagger, H., Von Jagow, G., (1987) Anal. Biochem., 166, pp. 368-379Scott, D.L., Achari, A., Vidal, J.C., Sigler, P.B., (1992) J. Biol. Chem., 267, pp. 22645-22657Soares, A.M., Marcussi, S., Stabeli, R.G., Franca, S.C., Giglio, J.R., Ward, R.J., Arantes, E.C., (2003) Biochem. Biophys. Res. Commun., 302, pp. 193-200Soares, A.M., Andrião-Escaso, S.H., Angulo, Y., Lomonte, B., Gutierrez, J.M., Marangoni, S., Toyama, M.H., Giglio, J.R., (2000) Arch. Biochem. Biophys., 373, pp. 7-15Toyama, M.H., Costa, P.D., Novello, J.C., Oliveira, B., Giglio, J.R., Cruz-Höfling, M.A., Marangoni, S., (1999) J. Protein Chem, 18, pp. 371-378Toyama, M.H., Deoliveira, D.G., Beriam, L.O., Novello, J.C., Rodrigues-Simioni, L., Marangoni, S., (2003) Toxicon, 41, pp. 1033-1038Verheij, H.M., Volwerk, J.J., Jansen, E.H., Puyk, W.C., Dijkstra, B.W., Drenth, J., De Haas, G.H., (1980) Biochemistry, 19, pp. 743-750Yang, C.C., (1997) Venom Phospholipase A2 Enzymes: Structure, Function and Mechanism, pp. 185-204. , Kini, R. M. (ed.), Wiley, Chichester U

Detecção da resistência a antibióticos de bactérias isoladas de casos clínicos ocorridos em animais de companhia Detection of antibiotic resistance in clinical bacterial strains from pets

<abstract language="eng">The identification of different bacterial strains and the occurrence of antibiotic resistance were investigated in several infection processes of pets as skin abscess with purulent discharge, bronco alveolar fluid, earwax, urine, mammary, and eye fluid. Streptococcus spp. and Staphylococcus spp. were the most detected in the different samples. A high frequency of antimicrobial resistance has been observed and this could reflect the wide use of antimicrobials in pets, making the effectiveness of antibiotic treatment to become more complicated

Immunotherapy and immunochemotherapy in visceral leishmaniasis: promising treatments for this neglected disease

Leishmaniasis has several clinical forms: self-healing or chronic cutaneous leishmaniasis or post-kala-azar dermal leishmaniasis; mucosal leishmaniasis; and visceral leishmaniasis, which is fatal if left untreated. The epidemiology and clinical features of VL vary greatly due to the interaction of multiple factors including parasite strains, vectors, host genetics, and the environment. HIV infection, augments the severity of VL increasing the risk of developing active disease by 100 to 2320 times. An effective vaccine for humans is not yet available. Resistance to chemotherapy is a growing problem in many regions, and the costs associated with drug identification and development, make commercial production for leishmaniasis, unattractive. The toxicity of currently drugs, their long treatment course, and limited efficacy are significant concerns. For cutaneous disease, many studies have shown promising results with immunotherapy/immunochemotherapy, aimed to modulate and activate the immune response to obtain a therapeutic cure. Nowadays, the focus of many groups centers on treating canine VL by using vaccines and immunomodulators with or without chemotherapy. In human disease, the use of cytokines like Interferon-γ associated with pentavalent antimonials demonstrated promising results in patients that did not respond to conventional treatment. In mice, immunomodulation based on monoclonal antibodies to remove endogenous immunosuppressive cytokines (interleukin-10) or block their receptors, antigen-pulsed syngeneic dendritic cells, or biological products like Pam3Cys (TLR ligand) has already been shown as a prospective treatment of the disease. This review addresses VL treatment, particularly immunotherapy and/or immunochemotherapy as an alternative to conventional drug treatment in experimental models, canine VL, and human disease