PESQUISA VETERINÁRIA BRASILEIRA

Abstract in English:

ABSTRACT.- Pereira I.A., Soares L.C., Coelho S.M.O., Pribul B.R. & Souza M.M.S. 2009. [Susceptibility to azithromycin of bacteria isolated from infectious processes in dogs and cats.] Suscetibilidade à azitromicina de isolados bacterianos de processos infecciosos em cães e gatos. Pesquisa Veterinária Brasileira 29(2):153-156. Departamento de Microbiologia e Imunologia Veterinária, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23890-000, Brazil. E-mail: miliane@ufrrj.br The susceptibility pattern to azithromycin of bacterial pathogens from various infectious sites, and the in vitro activity and minimum inhibitory concentration (MIC) of azithromycin were studied. Tests such as disc diffusion and broth microdilution detected respectively 48.6% and 55% of resistant Staphylococcus spp., and 55.3% and 72.7% resistant gram-negative rods. MIC50 for S. aureus was 4.0mg/mL, that for S. intermedius was 1.0mg/mL, for coagulase-negative Staphylococcus e”512mg/mL, and for gram-negative rods 256mg/mL. Fifteen percent (9/60) of oxacilin-resistant, multidrug-resistant and mecA-positive Staphylococcus spp. isolates were also azithromycin resistant. The dissemination of multidrug resistant bacteria points out to the need of antimicrobial evaluation activity in order to select the best indicated drug and thus minimizing therapeutic failures in veterinary practice.

• Diseases of dogs and cats bacterial diseases bacterial antibiotic resistance azithromycin

Abstract in Portuguese:

ABSTRACT.- Pereira I.A., Soares L.C., Coelho S.M.O., Pribul B.R. & Souza M.M.S. 2009. [Susceptibility to azithromycin of bacteria isolated from infectious processes in dogs and cats.] Suscetibilidade à azitromicina de isolados bacterianos de processos infecciosos em cães e gatos. Pesquisa Veterinária Brasileira 29(2):153-156. Departamento de Microbiologia e Imunologia Veterinária, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23890-000, Brazil. E-mail: miliane@ufrrj.br The susceptibility pattern to azithromycin of bacterial pathogens from various infectious sites, and the in vitro activity and minimum inhibitory concentration (MIC) of azithromycin were studied. Tests such as disc diffusion and broth microdilution detected respectively 48.6% and 55% of resistant Staphylococcus spp., and 55.3% and 72.7% resistant gram-negative rods. MIC50 for S. aureus was 4.0mg/mL, that for S. intermedius was 1.0mg/mL, for coagulase-negative Staphylococcus e”512mg/mL, and for gram-negative rods 256mg/mL. Fifteen percent (9/60) of oxacilin-resistant, multidrug-resistant and mecA-positive Staphylococcus spp. isolates were also azithromycin resistant. The dissemination of multidrug resistant bacteria points out to the need of antimicrobial evaluation activity in order to select the best indicated drug and thus minimizing therapeutic failures in veterinary practice.

Abstract in English:

ABSTRACT.- Ribeiro M.G., Geraldo J.S., Langoni H., Lara G.H.B., Siqueira A.K., Salerno T. & Fernandes M.C. 2008. [Pathogenic microorganisms, somatic cell count and drug residues evaluation in organic bovine milk.] Microrganismos patogênicos, celularidade e resíduos de antimicrobianos no leite produzido no sistema orgânico. Pesquisa Veterinária Brasileira 29(1):52-58. Disciplina de Enfermidades Infecciosas dos Animais, Departamento de Higiene Veterinária e Saúde Pública, Faculdade de Medicina Veterinária e Zootecnia, Universidade Estadual Paulista, Botucatu, SP 18618-000, Brazil. E-mail: mgribeiro@fmvz.unesp.br In last years increase the importance of milk quality and conditions of bovine milking. Simultaneously, increase the interest about organic milk and derivates. The aim of present study was investigate the milk pathogens, sensitivity and multiple drug resistance of isolates, somatic cell count and residues of drugs in milk, from cattle with and without mastitis, come from four little organic dairy farms in State of São Paulo, Brazil. Were used 148 cattle on the middle period of lactation. From these, two showed clinical mastitis, 72 subclinical mastitis and 74 without signs of mammary inflammation (control). Staphylococcus aureus (25.7%), Streptococcus spp. (21.4%), Corynebacterium bovis (12.9%), Streptococcus agalactiae (4.3%) and Staphylococcus spp (4,3%) were the more-frequent microorganisms isolated from animals with mastitis. Aspergillus spp. was isolated from one animal. Ceftiofur (95.2%), oxacillin (84.2%), gentamicin (76.3%) and cefoperazone (70.3%) were the more effective drugs. High resistance of isolates were found to penicillin (53.5%), ampicillin (41.6%) and neomycin (38.6%). Multiple drug resistance to three or more drug was observed in 40 (39.6%) isolates. Media of somatic cell count encountered in animals with mastitis and controls were 175,742.67cs/mL and 58,227.6 cs/mL, respectively. Antimicrobials residues in milk were detected in four (2.7%) animals. The present findings showed the low somatic cell count of animals, indicative of good quality of milk. However, pointed the need of control measures for contagious pathogens of bovine mastitis and more attention for prohibition of antimicrobial use in organic dairy farms.

• Organic milk mastitis bovine somatic cell count antimicrobials multiresistance

Abstract in Portuguese:

ABSTRACT.- Ribeiro M.G., Geraldo J.S., Langoni H., Lara G.H.B., Siqueira A.K., Salerno T. & Fernandes M.C. 2008. [Pathogenic microorganisms, somatic cell count and drug residues evaluation in organic bovine milk.] Microrganismos patogênicos, celularidade e resíduos de antimicrobianos no leite produzido no sistema orgânico. Pesquisa Veterinária Brasileira 29(1):52-58. Disciplina de Enfermidades Infecciosas dos Animais, Departamento de Higiene Veterinária e Saúde Pública, Faculdade de Medicina Veterinária e Zootecnia, Universidade Estadual Paulista, Botucatu, SP 18618-000, Brazil. E-mail: mgribeiro@fmvz.unesp.br In last years increase the importance of milk quality and conditions of bovine milking. Simultaneously, increase the interest about organic milk and derivates. The aim of present study was investigate the milk pathogens, sensitivity and multiple drug resistance of isolates, somatic cell count and residues of drugs in milk, from cattle with and without mastitis, come from four little organic dairy farms in State of São Paulo, Brazil. Were used 148 cattle on the middle period of lactation. From these, two showed clinical mastitis, 72 subclinical mastitis and 74 without signs of mammary inflammation (control). Staphylococcus aureus (25.7%), Streptococcus spp. (21.4%), Corynebacterium bovis (12.9%), Streptococcus agalactiae (4.3%) and Staphylococcus spp (4,3%) were the more-frequent microorganisms isolated from animals with mastitis. Aspergillus spp. was isolated from one animal. Ceftiofur (95.2%), oxacillin (84.2%), gentamicin (76.3%) and cefoperazone (70.3%) were the more effective drugs. High resistance of isolates were found to penicillin (53.5%), ampicillin (41.6%) and neomycin (38.6%). Multiple drug resistance to three or more drug was observed in 40 (39.6%) isolates. Media of somatic cell count encountered in animals with mastitis and controls were 175,742.67cs/mL and 58,227.6 cs/mL, respectively. Antimicrobials residues in milk were detected in four (2.7%) animals. The present findings showed the low somatic cell count of animals, indicative of good quality of milk. However, pointed the need of control measures for contagious pathogens of bovine mastitis and more attention for prohibition of antimicrobial use in organic dairy farms.

Abstract in English:

ABSTRACT.- Santos T.R.B., Farias N.A.R., Cunha Filho N.A., Pappen F.G. & Vaz Junior I.S. 2009. [Studies of the management of the tick Rhipicephalus (Boophilus) microplus in southern Rio Grande do Sul, Brazil.] Abordagem sobre o controle do carrapato Rhipicephalus (Boophilus) microplus no sul do Rio Grande do Sul. Pesquisa Veterinária Brasileira 29(1):65-70. Faculdade de Veterinária, Universidade Federal de Pelotas, Campus Universitário s/n, Cx. Postal 354, Pelotas, RS 96010-900, Brazil. E-mail: tsantos@ufpel.edu.br In the southern region of Rio Grande do Sul, cattle become infested with Rhipicephalus (B.) microplus mainly between October and April due to the climatic conditions. In addition to knowing its life cycle, knowledge of parasite’s epidemiology is essential to establish management strategies. Epidemiological studies on resistance to acaricides in Rio Grande do Sul as well as in the rest of Brazil are scarce. Moreover, the large geographical area and the structural deficiency with respect to the use and access to databases make reliable data difficult to obtain. The present study surveyed the perception by cattle breeders in the southern region of Rio Grande do Sul in regards of identification of R. (B.) microplus populations that are difficult to manage using acaricides, as well as the risk factors for the selection of resistant tick populations. Tick management data on beef cattle in 85 properties of seven municipalities were collected. The results revealed that the difficulty in tick management correlated positively with levels of education of the farm owners (up to elementary school, OR = 3.67 and p = 0.01) and with the yearly number of acaricide applications (over four, with OR = 4.05 and p= 0.006). These results also suggest that properties with more than 100 beef cattle under extensive farming conditions in the southern region of Rio Grande do Sul show characteristics that may contribute to longer acaricide lifetimes as compared to other regions in the Country.

• Rhipicephalus (Boophilus) microplus risk factors resistance acaricides South Brazil

Abstract in Portuguese:

ABSTRACT.- Santos T.R.B., Farias N.A.R., Cunha Filho N.A., Pappen F.G. & Vaz Junior I.S. 2009. [Studies of the management of the tick Rhipicephalus (Boophilus) microplus in southern Rio Grande do Sul, Brazil.] Abordagem sobre o controle do carrapato Rhipicephalus (Boophilus) microplus no sul do Rio Grande do Sul. Pesquisa Veterinária Brasileira 29(1):65-70. Faculdade de Veterinária, Universidade Federal de Pelotas, Campus Universitário s/n, Cx. Postal 354, Pelotas, RS 96010-900, Brazil. E-mail: tsantos@ufpel.edu.br In the southern region of Rio Grande do Sul, cattle become infested with Rhipicephalus (B.) microplus mainly between October and April due to the climatic conditions. In addition to knowing its life cycle, knowledge of parasite’s epidemiology is essential to establish management strategies. Epidemiological studies on resistance to acaricides in Rio Grande do Sul as well as in the rest of Brazil are scarce. Moreover, the large geographical area and the structural deficiency with respect to the use and access to databases make reliable data difficult to obtain. The present study surveyed the perception by cattle breeders in the southern region of Rio Grande do Sul in regards of identification of R. (B.) microplus populations that are difficult to manage using acaricides, as well as the risk factors for the selection of resistant tick populations. Tick management data on beef cattle in 85 properties of seven municipalities were collected. The results revealed that the difficulty in tick management correlated positively with levels of education of the farm owners (up to elementary school, OR = 3.67 and p = 0.01) and with the yearly number of acaricide applications (over four, with OR = 4.05 and p= 0.006). These results also suggest that properties with more than 100 beef cattle under extensive farming conditions in the southern region of Rio Grande do Sul show characteristics that may contribute to longer acaricide lifetimes as compared to other regions in the Country.

Abstract in English:

ABSTRACT.- Amarante A.F.T., Rocha R.A. & Bricarello P.A. 2006. Relationship of intestinal histology with the resistance to Trichostrongylus colubriformis infection in three breeds of sheep. Pesquisa Veterinária Brasileira 26(1):43-48. Departamento de Parasitologia, Instituto de Biociências, Universidade Estadual Paulista (Unesp), Cx. Postal 510, Botucatu, SP 18618-000, Brazil. E-mail: amarante@ibb.unesp.br The study was carried out to evaluate the relationship of inflammatory intestinal cells with the resistance to Trichostrongylus colubriformis infections in three breeds of sheep (Santa Ines, Suffolk and Ile de France), naturally infected. Mast cells, eosinophils, and globule leucocytes were enumerated in intestinal mucosa. Histamine concentration was estimated in intestinal tissue samples and the length of male and female specimens were determined. The three breeds of sheep showed similar cellular response in the small intestine mucosa (P>0.05). There was extensive variation among sheep in the parasitological and inflammatory cell variables, even in lambs of the same breed. In general, animals presenting less inflammatory cells had a larger worm burden, higher fecal egg counts, and larger T. colubriformis worms. The inflammatory cells possibly impaired the parasite’s establishment, development, and survival.

• Sheep Trichostrongylus colubriformis resistance mast cells eosinophils

Abstract in Portuguese:

ABSTRACT.- Amarante A.F.T., Rocha R.A. & Bricarello P.A. 2006. Relationship of intestinal histology with the resistance to Trichostrongylus colubriformis infection in three breeds of sheep. Pesquisa Veterinária Brasileira 26(1):43-48. Departamento de Parasitologia, Instituto de Biociências, Universidade Estadual Paulista (Unesp), Cx. Postal 510, Botucatu, SP 18618-000, Brazil. E-mail: amarante@ibb.unesp.br The study was carried out to evaluate the relationship of inflammatory intestinal cells with the resistance to Trichostrongylus colubriformis infections in three breeds of sheep (Santa Ines, Suffolk and Ile de France), naturally infected. Mast cells, eosinophils, and globule leucocytes were enumerated in intestinal mucosa. Histamine concentration was estimated in intestinal tissue samples and the length of male and female specimens were determined. The three breeds of sheep showed similar cellular response in the small intestine mucosa (P>0.05). There was extensive variation among sheep in the parasitological and inflammatory cell variables, even in lambs of the same breed. In general, animals presenting less inflammatory cells had a larger worm burden, higher fecal egg counts, and larger T. colubriformis worms. The inflammatory cells possibly impaired the parasite’s establishment, development, and survival.

Abstract in English:

ABSTRACT.- Costa M.M., Silva M.S., Spricigo D.A., Witt N.M., Marchioro S.B., Kolling L. & Vargas A.P.C. 2006. [Epidemiology, molecular characterization and resistance to antimicrobials of Escherichia coli isolated from South-Brazilian pig herds.] Caracterização epidemiológica, molecular e perfil de resistência aos antimicrobianos de Escherichia coli isoladas de criatórios suínos do Sul do Brasil. Pesquisa Veterinária Brasileira 26(1):5-8. Departamento de Medicina Veterinária Preventiva, Centro de Ciências Rurais, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil. E-mail: agueda@ccr.ufsm.br Colibacillosis is an enteric disease with a major impact to the swine industry and is caused by enterotoxigenic strains of Escherichia coli. Forty clinical isolates from pigs with diarrhea and 13 environmental isolates were analysed regarding their genotypic profile, genetic relationship and antibiotic resistance. The most prevalent gene was Stb, identified in 50% of the isolates from clinical cases, and Sta and Lt were detected in 35% of them. Among the adesine factors investigated, F18 was found in 27.5% of the E. coli strains. The ERIC-PCR technique used for epidemiological characterization of the isolates did not show the expected discriminatory power. However, the test allowed separation of the isolates in groups, but did not evidence groups related to virulence factors. In the susceptibility test, the highest values for resistance were to tetracycline, in 88.6%. The index of multiple resistance to antimicrobials varied from 0 to 0.69.

• Escherichia coli genotypic profile resistance.

Abstract in Portuguese:

ABSTRACT.- Costa M.M., Silva M.S., Spricigo D.A., Witt N.M., Marchioro S.B., Kolling L. & Vargas A.P.C. 2006. [Epidemiology, molecular characterization and resistance to antimicrobials of Escherichia coli isolated from South-Brazilian pig herds.] Caracterização epidemiológica, molecular e perfil de resistência aos antimicrobianos de Escherichia coli isoladas de criatórios suínos do Sul do Brasil. Pesquisa Veterinária Brasileira 26(1):5-8. Departamento de Medicina Veterinária Preventiva, Centro de Ciências Rurais, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil. E-mail: agueda@ccr.ufsm.br Colibacillosis is an enteric disease with a major impact to the swine industry and is caused by enterotoxigenic strains of Escherichia coli. Forty clinical isolates from pigs with diarrhea and 13 environmental isolates were analysed regarding their genotypic profile, genetic relationship and antibiotic resistance. The most prevalent gene was Stb, identified in 50% of the isolates from clinical cases, and Sta and Lt were detected in 35% of them. Among the adesine factors investigated, F18 was found in 27.5% of the E. coli strains. The ERIC-PCR technique used for epidemiological characterization of the isolates did not show the expected discriminatory power. However, the test allowed separation of the isolates in groups, but did not evidence groups related to virulence factors. In the susceptibility test, the highest values for resistance were to tetracycline, in 88.6%. The index of multiple resistance to antimicrobials varied from 0 to 0.69.

Abstract in English:

Lázaro N.S., Tibana A., Rodrigues D.P., Reis E.M.F., Quintaes B.R. & Hofer E. 2004. Antimicrobial resistance and R-plasmid in Salmonella spp from swine and abattoir environments. Pesquisa Veterinária Brasileira 24(2):57-60. Depto Epidemiologia e Saúde Pública, Instituto de Veterinária, UFRRJ, Seropédica, RJ 23890-000, Brazil. E-mail: nslazaro@aol.com Salmonella serovars isolated from swine are of particular interest not only because of the pathogenic potential for this animal species, but also due to its relevance with regard to public health. On basis of the profile of resistance to antimicrobials, 13 Salmonella strains were selected which belonged to the serovars Muenster (7), Derby (4), Typhimurium (1), and Braenderup (1). They were isolated from healthy swine as well as from the abattoir environment in the state of Rio de Janeiro. All strains of Salmonella were subjected to bacterial conjugation, and the E. coli K12 Nalr Lac+ F standard strain was used as receptor, with the purpose to verify the ability to transfer the resistance marks. Gene transfer phenomenon was detected in seven strains, and except Salmonella Typhimurium which transconjugated to Sm, Tc and Su, the remaining ones were characterized by transferring mark Su only. By plasmidial analysis of strains used and their respective transconjugants, 63 Kb plasmid was found, which was probably related to S. Typhimurium resistance.

• Salmonella swine antimicrobial resistance R-plasmid.

Abstract in Portuguese:

Lázaro N.S., Tibana A., Rodrigues D.P., Reis E.M.F., Quintaes B.R. & Hofer E. 2004. Antimicrobial resistance and R-plasmid in Salmonella spp from swine and abattoir environments. Pesquisa Veterinária Brasileira 24(2):57-60. Depto Epidemiologia e Saúde Pública, Instituto de Veterinária, UFRRJ, Seropédica, RJ 23890-000, Brazil. E-mail: nslazaro@aol.com Salmonella serovars isolated from swine are of particular interest not only because of the pathogenic potential for this animal species, but also due to its relevance with regard to public health. On basis of the profile of resistance to antimicrobials, 13 Salmonella strains were selected which belonged to the serovars Muenster (7), Derby (4), Typhimurium (1), and Braenderup (1). They were isolated from healthy swine as well as from the abattoir environment in the state of Rio de Janeiro. All strains of Salmonella were subjected to bacterial conjugation, and the E. coli K12 Nalr Lac+ F standard strain was used as receptor, with the purpose to verify the ability to transfer the resistance marks. Gene transfer phenomenon was detected in seven strains, and except Salmonella Typhimurium which transconjugated to Sm, Tc and Su, the remaining ones were characterized by transferring mark Su only. By plasmidial analysis of strains used and their respective transconjugants, 63 Kb plasmid was found, which was probably related to S. Typhimurium resistance.

Abstract in English:

Lázaro N.S., Tibana A., Reis E.M.F., Rodrigues D.P., Quintaes B.R. & Hofer E. 2004. [Antimicrobial susceptibility pattern and plasmid profile in Salmonella Muenster isolated from swine and abattoir environment, Brazil.] Padrão de susceptibilidade a antimicrobianos e perfil plasmidial em Salmonella Muenster isoladas de suínos e do ambiente de abatedouros. Pesquisa Veterinária Brasileira 24(2):65-70. Depto Epidemiologia e Saúde Pública, Inst.Veterinária, UFRRJ, Seropédica, RJ 23890-000, Brazil. E-mail: nslazaro@aol.com Thirty-eight strains of Salmonella Muenster, isolated from swine and the abattoir environment, in the State of Rio de Janeiro, Brazil, from March 1991 to February 1992, were analyzed for the presence of plasmids. The strains were selected according to their profile regarding the antimicrobials: streptomycin, tetracycline, sulphonamide and sulfametoxazole-trimethoprim. Thirteen strains were resistant to one or several antimicrobials, 18 with intermediate degree and seven were sensitive. Plasmids varying in size from 1.2 Kb to 42 Kb were detected in 37 (97.36%) of the 38 samples, corresponding to 11 different profiles (P1- P11), varying from 1 to 6 plasmids per model. The number and plasmids diversity was greater than the resistance marks for strains. The plasmid of 2.85 Kb was the most frequent, being present in 83.78% of the 37 strains; only the one of 7.5 Kb was detected at the two slaughterhouses. There was no parallelism between resistance pattern and plasmidial profile, and a same antibiotype was found in several plasmidial profiles. The results of the present investigation, allowed us to conclude that the plasmid characterization is an useful and simple tool for the epidemiological typing of this sorovar.

• Salmonella Muenster swine antimicrobial resistance plasmids.

Abstract in Portuguese:

Lázaro N.S., Tibana A., Reis E.M.F., Rodrigues D.P., Quintaes B.R. & Hofer E. 2004. [Antimicrobial susceptibility pattern and plasmid profile in Salmonella Muenster isolated from swine and abattoir environment, Brazil.] Padrão de susceptibilidade a antimicrobianos e perfil plasmidial em Salmonella Muenster isoladas de suínos e do ambiente de abatedouros. Pesquisa Veterinária Brasileira 24(2):65-70. Depto Epidemiologia e Saúde Pública, Inst.Veterinária, UFRRJ, Seropédica, RJ 23890-000, Brazil. E-mail: nslazaro@aol.com Thirty-eight strains of Salmonella Muenster, isolated from swine and the abattoir environment, in the State of Rio de Janeiro, Brazil, from March 1991 to February 1992, were analyzed for the presence of plasmids. The strains were selected according to their profile regarding the antimicrobials: streptomycin, tetracycline, sulphonamide and sulfametoxazole-trimethoprim. Thirteen strains were resistant to one or several antimicrobials, 18 with intermediate degree and seven were sensitive. Plasmids varying in size from 1.2 Kb to 42 Kb were detected in 37 (97.36%) of the 38 samples, corresponding to 11 different profiles (P1- P11), varying from 1 to 6 plasmids per model. The number and plasmids diversity was greater than the resistance marks for strains. The plasmid of 2.85 Kb was the most frequent, being present in 83.78% of the 37 strains; only the one of 7.5 Kb was detected at the two slaughterhouses. There was no parallelism between resistance pattern and plasmidial profile, and a same antibiotype was found in several plasmidial profiles. The results of the present investigation, allowed us to conclude that the plasmid characterization is an useful and simple tool for the epidemiological typing of this sorovar.

Abstract in English:

Pereira M.S.V., Siqueira Júnior J.P. & Campos Takaki G.M. 2004. [Elimination of resistance to drugs by fluoroquinolones in bovine strains of Staphylococcus aureus.] Eliminação de resistência a drogas por fluorquinolonas em Staphylococcus aureus de origem bovina. Pesquisa Veterinária Brasileira 24(1):11-14. Depto Biologia Molecular, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraiba, João Pessoa, PB 58059-900, Brazil. E-mail: svieira@dbm.ufpb.br Bovine strains of Staphylococcus aureus were submitted to treatment with four fluoro-quinolones in subinhibitory concentrations (1/2 x MICs) to evaluate their influence on the curing of plasmids. Ciprofloxacin showed to be the most efficient by eliminating resistance to streptomycin, tetracyclin, penicillin, and cadmium nitrate. Norfloxacin and pefloxacin eliminated penicillin- and tetracyclin-resistance respectively. Otherwise, plasmids elimination by ofloxacin was not evidenced. The results obtained in this study confirm the potential of fluoroquinolones to eliminate antibiotic-resistant plasmids, and showed to be a valuable contribution for the prevention of multi-resistant strains, and may even enhance their sensitivity to other chemotherapeutic agents.

• Staphylococcus aureus fluoroquinolones elimination of resistance to drugs.

Abstract in Portuguese:

Pereira M.S.V., Siqueira Júnior J.P. & Campos Takaki G.M. 2004. [Elimination of resistance to drugs by fluoroquinolones in bovine strains of Staphylococcus aureus.] Eliminação de resistência a drogas por fluorquinolonas em Staphylococcus aureus de origem bovina. Pesquisa Veterinária Brasileira 24(1):11-14. Depto Biologia Molecular, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraiba, João Pessoa, PB 58059-900, Brazil. E-mail: svieira@dbm.ufpb.br Bovine strains of Staphylococcus aureus were submitted to treatment with four fluoro-quinolones in subinhibitory concentrations (1/2 x MICs) to evaluate their influence on the curing of plasmids. Ciprofloxacin showed to be the most efficient by eliminating resistance to streptomycin, tetracyclin, penicillin, and cadmium nitrate. Norfloxacin and pefloxacin eliminated penicillin- and tetracyclin-resistance respectively. Otherwise, plasmids elimination by ofloxacin was not evidenced. The results obtained in this study confirm the potential of fluoroquinolones to eliminate antibiotic-resistant plasmids, and showed to be a valuable contribution for the prevention of multi-resistant strains, and may even enhance their sensitivity to other chemotherapeutic agents.

Abstract in English:

ABSTRACT.- Molento M.B. & Prichard R.K. 2001. Effect of multidrug resistance modulators on the activity of ivermectin and moxidectin against selected strains of Haemonchus contortus infective larvae. [Efeito de drogas moduladoras da resistência múltipla na atividade da ivermectina e moxidectina contra larvas infectantes selecionadas de Haemonchus contortus.] Pesquisa Veterinária Brasileira, 21(3):117-121. Setor de Parasitologia, Universidade Paranaense, Umuarama, PR 87502-210, Brazil. E-mail: molento@unipar.br Nematode parasites have shown resistance to the anthelmintics, ivermectin and moxidectin, and there is evidence that the over-expression of parasite P-glycoprotein (P-gp) may account, at least in part, for resistance to ivermectin. The objective of this study was to evaluate whether the multidrug resistance (MDR) modulators, verapamil, CL 347.099 (an analog of verapamil) and cyclosporin A, would enhance the efficacy of ivermectin and moxidectin against selected strains of Haemonchus contortus using an in vitro larval migration assay. The modulators had no effects on the number of migrating larva e when used alone. lvermectin and moxidectin showed a significant (P<0.05) increase in its efficacy by 52.8 and 58.5% respectively, when used in association with verapamil against a moxidectin-selected strain. CL 347,099 also increased significantly (P<0.05) the ivermectin and moxidectin efficacy by 24.2 and 40.0% respectively, against an ivermectin-selected strain and by 40.0 and 75.6% respectively, against an moxidectinselected strain. At the concentrations tested cyclosporin A showed a variable effect on increasing the efficacy of the anthelmintics against the susceptible and resistant strains.

• Nematode multidrug resistance (MOR) ivermectin moxidectin modulators verapamil CL 347.099 cyclosporin A Nematóides resistência múltipla (MOR) ivermectina moxidectina moduladores verapamil ciclosporina A.

Abstract in Portuguese:

RESUMO.- Molento M.B. & Prichard R.K. 2001. Effect of multidrug resistance modulators on the activity of ivermectin and moxidectin against selected strains of Haemonchus contortus infective larvae. [Efeito de drogas moduladoras da resistência múltipla na atividade da ivermectina e moxidectina contra larvas infectantes selecionadas de Haemonchus contortus.] Pesquisa Veterinária Brasileira, 21(3):117-121. Setor de Parasitologia, Universidade Paranaense, Umuarama, PR 87502-210, Brazil. E-mail: molento@unipar.br Existem relatos demonstrando a resistência de nematóides aos anti-helmínticos, ivermectina e moxidectina. O aumento da expressão da glicoproteína-P (P-gp) no parasita pode contribuir para o desenvolvimento da resistência a ivermectina. O objetivo deste trabalho foi avaliar se o uso combinado dos moduladores de resistência múltipla, verapamil, CL 347.099 (um análogo do verapamil) e ciclosporina A associados a ivermectina ou moxidectina, aumenta a eficácia dos anti-helmínticos contra cepas selecionacllas de Haemonchus contortus, utilizando um experimento in vitro de migração de larvas. ivermectina e moxidectina apresentaram um aumento significativo (P<0,05) de sua eficácia em 52,8 e 58,5%, respectivamente, quando utilizadas em associação com o verapamil contra a cepa selecionada para moxidectina. CL 347.099 também aumentou significativamente (P<0,05) a eficácia de ivermectina e de moxidectina em 24,2 e 40,0%, respectivamente, contra a cepa selecionada para a ivermectina e em 40,0 e 75,6% respectivamente, contra a cepa selecionada para moxidectina. Nas concentrações testadas, ciclosporina A apresentou resultados variáveis quando combinada com os anti-helmínticos. Quando utilizados sozinhos, os moduladores não apresentarão efeito na redução do número de larvas.

Abstract in English:

ABSTRACT.- Vieira L.S. & Cavalcante A.C.R. 1999. [Anthelmintic resistance in goat herds in the State of Ceará.] Resistência anti-helmíntica em rebanhos caprinos no Estado do Ceará. Pesquisa Veterinária Brasileira 19(3/4):99-103. Embrapa-CNPC, Km 4 da Estrada Sobral-Groaíras, Cx. Postal 0-10, Sobral, CE 62011-970, Brazi. Goats of 45 farms in the State of Ceará, Brazil, were treated with anthelmintics for gastrointestinal nematodes, and their resistance to the anthelmintics was evaluated. On each farm 30 kids were weighed, ear-tagged and divided into three groups of ten. The first group received oxfendazole at 4.75mg/kg, the second levamisole at 7.5mg/kg, and the third group remained untreated as control. All goats were drenched according to their individual body weight. Fecal samples were collected from all animals (treated and control) on the day of treatment and 7 days later, to provide material for egg counts and larval cultures. Among 34 surveyed herds 20.6% showed levamisole resistance, 17.6% showed resistance to benzimidazole, and 35.3% had multiple resistance. At the time of the assessment 52.9% of the farmers were using broad spectrum anthelmintics. Only 26.5% of the surveyed herds had nematode populations susceptible to the anthelmintics assessed. The results of larval cultures showed that larvae surviving the treatment with oxfendazole were mainly Haemonchus sp and, to a lesser extent, Oesophagostomum sp; those surviving levamisole treatment were Haemonchus sp, Oesophagostomum sp and Trichostrongylus sp.

• Goats gastrointestinal nematodes anthelmintics anthelmintic resistance Caprinos nematódeos gastrintestinais anti-helmínticos resistência anti-helmíntica.

Abstract in Portuguese:

RESUMO.- Vieira L.S. & Cavalcante A.C.R. 1999. [Anthelmintic resistance in goat herds in the State of Ceará.] Resistência anti-helmíntica em rebanhos caprinos no Estado do Ceará. Pesquisa Veterinária Brasileira 19(3/4):99-103. Embrapa-CNPC, Km 4 da Estrada Sobral-Groaíras, Cx. Postal 0-10, Sobral, CE 62011-970, Brazi. Um levantamento em nível de campo sobre resistência anti-helmíntica em nematódeos gastrintestinais de; caprinos foi realizado em 34 rebanhos no Estado do Ceará. Em cada rebanho foram separados 30 cabritos, de ambos os sexos, com idade variando de 1 a 6 meses, os quais foram individualmente pesados, identificados e distribuídos em três tratamentos: 1) Oxfendazole na dose de 4, 75mg/kg; 2) Levamisole na dose de 7,5 mg/kg e 3) Controle (não medicado). Os anti-helmínticos foram administrados de acordo com o peso individual de cada animal e, a dosagem utilizada para cada produto foi a recomendada pelo laboratório fabricante. Foram colhidas fezes dos animais de todos os tratamentos, para OPG e coprocultura, no dia da medicação e 7 dias após. Dos 34 rebanhos avaliados, 7 (20,6%) apresentaram resistência aos imidazóis, 6 (17,6%) aos benzimidazóis e 12 (35,3%) revelaram resistência múltipla. Apenas em 9 rebanhos (26,5%), os nematódeos foram sensíveis aos anti-helmínticos avaliados. Através do questionário aplicado detectou-se que 52,9% dos caprinocultores entrevistados usavam anti-helmínticos de amplo espectro. Os resultados das coproculturas mostraram que os gêneros sobreviventes à medicação com oxfendazole foram principalmente Haemonchus sp, seguido em menor frequência por Oesophagostomum sp, enquanto que ao cloridrato de levamisole sobreviveram Haemonchus sp, Oesophagostomum sp e Trichostrongylus sp.