Evaluation of the relative expression of genes associated with adherence after different hours of co-culture between Streptococcus uberis and MAC-T cells

Streptococcus uberis is an environmental pathogen associated with subclinical and clinical IMI in both lactating and non-lactating cows. RC19 strain was isolated from a cow with subclinical mastitis, qualitatively classified as moderate biofilm producer in Todd Hewitt medium (THB), and it showed a high value of the adhered bacteria (CFU/ml). Hence, the aims of this study were (a) to determine ability to adhere to and internalize into epithelial cells MAC-T for 1, 2 and 3 h, (b) to evaluate the relative expression of adherence-associated genes from co-cultures of S. uberis with MAC-T cells at 1, 2 and 3 h. We hypothesized that upon contact with bovine mammary epithelial cells, S. uberis upregulates adherence-associated genes encoding adhesins, which enable it a higher adherence to and/or internalization into host cells. Four to six genes increased their R with regard to the control after initial contact with MAC-T cells (group 1) at 1, 2 and 3 h. The highest value of R was observed at 2 h after co-culture between RC19 and MAC-T cells.Fil: Fessia, Alumine Soledad. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Odierno, Liliana Mónica. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentin

Rep-pcr de Staphylococcus aureus isolados a partir de mastite bovina na Argentina

The aim of this study was to assess by rep-PCR the genetic relationship of 52 S. aureus strains isolated from mammary infections collected in four herds located in the central dairy region of Argentina. Results were compared with the in vitro activity of antimicrobial drugs frequently used for treating bovine mastitis. Twelve different antimicrobials patterns were observed. Forty eight percent of the strains were susceptible to all antimicrobials tested. rep-PCR typing could successfully differentiate S. aureus strains of bovine origin. At a first level of similarity (50%), it could be defined 5 clusters namely I to V. Most of the strains (75%) were grouped in cluster I. The results may suggest that genotypes were similar in the different herds. Agreement between antibiotic patterns and rep-profiles was not observed for most isolates. The present report describes the genotypes responsible for the mastitis cases in the central dairy region of Argentina. A better knowledge of infective strains distribution in dairy herds might help in formulating strategies to control of infection. Furthermore, antimicrobial susceptibility of S. aureus should be used as guide to select effective drugs to therapy in intramammary infections.O objetivo do presente estudo foi determinar a relação genética entre rep-PCR de 52 linhagens Staphylococcus aureus isoladas de infecções mamárias em quatro fazendas leiteiras da região leiteira central da Argentina. Os resultados foram comparados com a atividade in vitro dos antimicrobianos freqüentemente utilizados no tratamento da mastite bovina. Foram observados 12 diferentes perfis de antimicrobianos. Do total de linhagens, 45% foram suscetíveis a todos os antibióticos ensaiados. A caracterizacão por rep-PCR pode diferenciar com sucesso as linhagens de S. aureus de origem bovina. Num primeiro nível de similaridade (50%) foram definidos cinco grupos denominados de I a V. A maioria das estirpes (75%) agruparam-se no grupo I. Os resultados sugerem que os genotipos foram similares. Os genotipos não foram asociados com os perfis de antimicrobianos na maioria dos isolados. O presente estudo descreve os genotipos responsáveis pelos casos de mastites na região central da Argentina. O melhor conhecimento da distribução das linhagens infectantes em fazendas leiteras poderia auxiliar na formulacão de estratégias para o controle de infecção. Além disso a suscetibilidade aos antimicrobianos de linhagens de S. aureus deve ser usada para montear a selecão de drogas efetivas para a terapia intramamária

Genetic patterns of Streptococcus uberis isolated from bovine mastitis

The aim of this study was to evaluate the genotypic relationships among 40 Streptococcus uberis isolated from bovine mastitis by using pulsed-field gel electrophoresis (PFGE). Additionally, the association between PFGE patterns and virulence profiles was investigated. The isolates exhibited 17 PFGE patterns. Different strains were found within and among herds; however, a low number of isolates within the same herd shared an identical PFGE type. No association between PFGE patterns and virulence profiles was found. However, the detection of specific strains in some herds could indicate that some strains are more virulent than others. Further research needs to be undertaken to elucidate new virulence-associated genes that might contribute to the capability of these strains to produce infection.El objetivo del presente estudio fue evaluar las relaciones genotípicas entre 40 Streptococcus uberis aislados de mastitis bovina mediante la técnica de electroforesis de campos pulsantes (pulsed-field gel electrophoresis [PFGE]). Además, se investigó la asociación entre los patrones de PFGE y los perfiles de virulencia. Los aislamientos mostraron 17 patrones de PFGE. Se encontraron diferentes cepas dentro de los tambos y en los distintos tambos, y un bajo número de aislamientos dentro del mismo tambo compartieron un perfil idéntico de PFGE. No se encontró ninguna asociación entre los patrones de PFGE y los perfiles de virulencia. Sin embargo, la detección de cepas particulares en algunos tambos podría indicar que algunas de ellas son más virulentas que otras. Sería importante avanzar en las investigaciones para identificar nuevos genes relacionados con la virulencia que podrían contribuir a la capacidad infecciosa de estas cepas.Fil: Reinoso, Elina Beatríz. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lasagno, Mirta C.. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; ArgentinaFil: Odierno, Liliana M.. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentin

Comparison of phenotypic tests for detecting penicillin G resistance with presence of blaZ gene in Staphylococcus aureus isolated from bovine intramammary infections

Few studies have described the relationship between genotypic and phenotypic methods for detecting penicillin resistance in Staphylococcus aureus isolated from bovine intramammary infection (IMI). Six phenotypic methods for penicillinase detection were compared with a genotypic method testing the presence of the β-lactamase gene blaZ in Staph. aureus (n = 150) isolated from bovine IMI. Highest sensitivities and specificities were observed for disk diffusion (DD) (93 and 97·4%), minimum inhibitory concentration (MIC) (90·3 and 97·4%), Cefinase™ (85·9 and 97·4%) and Diatabs™ (85·7 and 98·7%). The estimated cut-off points estimated in the present study can be considered close to the ones indicated by CLSI (2013). The molecular detection of blaZ gene is the only method that may indicate the real or potential capacity of producing β-lactamase in Staph. aureus. Considering that from a clinical standpoint a false negative result from a phenotypic test is the most unfavourable situation, a combination of standard DD with Diatabs™ or Cefinase™ should be performed by routine mastitis laboratories to minimise false negative results.EEA RafaelaFil: Russi, Norma B.. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; ArgentinaFil: Maito, Julia. Lactodiagnóstico Sur; ArgentinaFil: Dieser, Silvana Andrea. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales; ArgentinaFil: Renna, Maria Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Signorini, Marcelo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Camussone, Cecilia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Neder, Veronica Elizabeth. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Pol, Martín. Lactodiagnóstico Sur; ArgentinaFil: Tirante, Liliana. Lactodiagnóstico Sur; ArgentinaFil: Odierno, Liliana Mónica. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; ArgentinaFil: Calvinho, Luis Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias; Argentin

Potential factors involved in the early pathogenesis of Streptococcus uberis mastitis: a review

Bovine mastitis is an inflammation of the mammary gland, which could be the result of allergy, physical trauma, or invasion by pathogens as Streptococcus uberis. This pathogen is an environmental pathogen associated with subclinical and clinical intramammary infection (IMI) in both lactating and non-lactating cows, which can persist in the udder and cause a chronic infection in the mammary gland. In spite of the important economic losses and increased prevalence caused by S. uberis mastitis, virulence factors involved in bacterial colonization of mammary glands and the pathogenic mechanisms are not yet clear. In the last 30 years, several studies have defined adherence and internalization of S. uberis as the early stages in IMI. S. uberis adheres to and invades into mammary gland cells, and this ability has been observed in in vitro assays. Until now, these abilities have not been determined in vivo challenges since they have been difficult to study. Bacterial surface proteins are able to bind to extracellular matrix protein components such as fibronectin, collagen and laminin, as well as proteins in milk. These proteins play a role in adhesion to host cells and have been denominated microbial surface components recognizing adhesive matrix molecules (MSCRAMMs). This article aims to summarize our current knowledge on the most relevant properties of the potential factors involved in the early pathogenesis of S. uberis mastitis.Fil: Fessia, Alumine Soledad. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Odierno, Liliana Mónica. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentin

Genotipificación de Staphylococcus aureus: Caracterización genotípica de Staphylococcus aureus aislados de mastitis bovina

La mastitis bovina es la enfermedad de mayor prevalencia y la de mayor impacto económico en la explotación lechera a nivel mundial. Staphylococcus aureus es el patógeno contagioso más prevalente en mastitis subclínica (MSC). El objetivo del presente trabajo fue caracterizar genotípicamente especies del género Stahylococcus coagulasa positivos, aislados de MSC en establecimientos de la cuenca lechera central de Argentina. Cuarenta y tres aislamientos fueron identificados como S. aureus por PCR-RFLP del gen groEL. De los perfiles genéticos obtenidos mediante PFGE de S. aureus se identificaron 2 pulsotipos diferentes (A, 76,7% y B, 23,2%). Se detectaron genes asociados a virulencia (nuc, clfA, coa, spa-Xr, spa-IgG, hla, hlb, cap5, cap8, icaA, icaD) mediante PCR, en los 32 S. aureus con pulsotipo A. Se identificaron 23 perfiles de virulencia en S. aureus, demostrando que aislamientos con diferentes perfiles de virulencia son capaces de causar MSC. Del análisis feno y genotípico de sensibilidad a antibióticos se demostró que la resistencia a β-lactámicos, macrólidos y lincosamidas no es un problema importante en los tambos en estudio.Fil: Dieser, Silvana Andrea. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Odierno, Liliana Mónica. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentin