RESUMEN

Acacia aroma, native plant from San Luis, Argentina, is commonly used as antiseptic and for healing of wounds. The present study was conducted to investigate the in vitro cytotoxicity and genotoxicity of hot aqueous extract (HAE) and ethanolic extract (EE) of A. aroma. The cytotoxic activity was assayed by neutral red uptake assay on Vero cell. Cell treatment with a range from 100 to 5000 µg/mL of HAE and EE showed that 500 µg/mL and 100 µg/mL were the maximum noncytotoxic concentrations, respectively. The CC50 was 658 µg/mL for EE and 1020 µg/mL for HAE. The genotoxicity was tested by the single-cell gel electrophoresis comet assay. The results obtained in the evaluation of DNA cellular damage exposed to varied concentrations of the HAE showed no significant genotoxic effect at range of 1-20 mg/mL. The EE at 20 mg/mL showed moderate genotoxic effect related to the increase of the DNA percentage contained in tail of the comet; DNA was classified in category 2. At concentrations below 5 mg/mL, the results of cytotoxicity and genotoxicity of aqueous and ethanolic extracts of Acacia aroma guarantee the safety at cell and genomic level. However further studies are needed for longer periods including animal models to confirm the findings.

Asunto(s)

RESUMEN

Different food samples of animal origin were analyzed for Listeria spp. Five L. innocua strains, one L. monocytogenes strain and one L. welshimeri strain were obtained from 208 samples of raw milk. The strains were typified by biochemical and serologic tests. The shortened enrichment method was chosen for isolations; Palcam and Oxford agar also permitted the growth of the seven strains. L. monocytogenes was recovered from milk of an animal with subclinical mastitis. No Listeria strains were isolated from pasteurized milk, chocolate milk or cheese samples. One L. welshimeri strain was detected in ice cream. In the case of meat food samples, the employment of two-step enrichment methods facilitated the detection of Listeria spp. A prevalence of L. ivanovii was observed in 2.5% of these samples.

Asunto(s)

RESUMEN

Se analizaron diferentes alimentos de origen animal para detectar la presencia de Listeria spp. De 208 muestras de leche cruda de tambo, se obtuvieron 5 capas de Listeria innocua, 1 de L. monocytogenes y 1 de L. welshimeri, tipificadas por pruebas bioquímicas y serológicas. El método de enriquecimiento rápido resultó el de elección y tanto el agar Palcam como el agar Oxford permitieron el crecimeitno de las 7 cepas. L. monocytogenes se recuperó de la leche de un animal con mastitis subclínica. Ninguna de las muestras analizadas de leches pasteurizadas o chocolatada ni de quesos contenía listeria, en cambio en las de helados se recuperó una cepa de L. welshimeri. Para los alimentos cárnicos, el empleo de enriquecimiento en 2 etapas facilitó la detección de Listeria spp. Se observó un predominio de L. ivanovii en el 2,5 por ciento de las muestras

Asunto(s)

RESUMEN

Se analizaron diferentes alimentos de origen animal para detectar la presencia de Listeria spp. De 208 muestras de leche cruda de tambo, se obtuvieron 5 capas de Listeria innocua, 1 de L. monocytogenes y 1 de L. welshimeri, tipificadas por pruebas bioquímicas y serológicas. El método de enriquecimiento rápido resultó el de elección y tanto el agar Palcam como el agar Oxford permitieron el crecimeitno de las 7 cepas. L. monocytogenes se recuperó de la leche de un animal con mastitis subclínica. Ninguna de las muestras analizadas de leches pasteurizadas o chocolatada ni de quesos contenía listeria, en cambio en las de helados se recuperó una cepa de L. welshimeri. Para los alimentos cárnicos, el empleo de enriquecimiento en 2 etapas facilitó la detección de Listeria spp. Se observó un predominio de L. ivanovii en el 2,5 por ciento de las muestras(AU)

Asunto(s)

RESUMEN

Different food samples of animal origin were analyzed for Listeria spp. Five L. innocua strains, one L. monocytogenes strain and one L. welshimeri strain were obtained from 208 samples of raw milk. The strains were typified by biochemical and serologic tests. The shortened enrichment method was chosen for isolations; Palcam and Oxford agar also permitted the growth of the seven strains. L. monocytogenes was recovered from milk of an animal with subclinical mastitis. No Listeria strains were isolated from pasteurized milk, chocolate milk or cheese samples. One L. welshimeri strain was detected in ice cream. In the case of meat food samples, the employment of two-step enrichment methods facilitated the detection of Listeria spp. A prevalence of L. ivanovii was observed in 2.5

of these samples.

RESUMEN

Recent food listeriosis outbreaks confirm that more faithful isolation and identification methods for Listeria monocytogenes or other potentially pathogen microorganisms are required. Furthermore, the human and animal reservoir role in the ecology of this disease must be established. Listeria spp. in the vizcacha intestinal content was determined by two isolation procedures, starting from 10 g of homogenized samples in 40 ml of PBS. I)0.1 ml was stripped on phenylethanol agar, selective agar for Listeria and acryflavin ceftazidin agar, then incubated at 37 degrees C for 48 h, suspected colonies were identified by preliminary tests (Gram, hemolysis, catalase, esculin hydrolisis and motility at 22 degrees C) and confirmatory tests (indol, methyl red, Voges Proskauer, nitrate and carbohydrate fermentation) (Table 1). Antibiotic susceptibility, protein profile by PAGE and pathogenic power in mice were determined. II) The remaining homogenate was incubated at 4 degrees C in 100 ml of Donnelly and Baigent enrichment broth, weekly or monthly with subcultures until 30 days or 6-8 months, respectively. The subcultures were followed up as in I). A L. seeligeri strain, susceptible to antibiotics suggested for L. monocytogenes and exhibiting resistance to some second and third generation cephalosporins, was isolated (Table 2). The protein profile of both species was coincident, but L. seeligeri was not virulent for mice. The finding of L. seeligeri in an animal (4.0%) used as human feeding source is of interest due to its potential pathogen power.

Asunto(s)

RESUMEN

Recent food listeriosis outbreaks confirm that more faithful isolation and identification methods for Listeria monocytogenes or other potentially pathogen microorganisms are required. Furthermore, the human and animal reservoir role in the ecology of this disease must be established. Listeria spp. in the vizcacha intestinal content was determined by two isolation procedures, starting from 10 g of homogenized samples in 40 ml of PBS. I)0.1 ml was stripped on phenylethanol agar, selective agar for Listeria and acryflavin ceftazidin agar, then incubated at 37 degrees C for 48 h, suspected colonies were identified by preliminary tests (Gram, hemolysis, catalase, esculin hydrolisis and motility at 22 degrees C) and confirmatory tests (indol, methyl red, Voges Proskauer, nitrate and carbohydrate fermentation) (Table 1). Antibiotic susceptibility, protein profile by PAGE and pathogenic power in mice were determined. II) The remaining homogenate was incubated at 4 degrees C in 100 ml of Donnelly and Baigent enrichment broth, weekly or monthly with subcultures until 30 days or 6-8 months, respectively. The subcultures were followed up as in I). A L. seeligeri strain, susceptible to antibiotics suggested for L. monocytogenes and exhibiting resistance to some second and third generation cephalosporins, was isolated (Table 2). The protein profile of both species was coincident, but L. seeligeri was not virulent for mice. The finding of L. seeligeri in an animal (4.0

) used as human feeding source is of interest due to its potential pathogen power.

RESUMEN

Recent food listeriosis outbreaks confirm that more faithful isolation and identification methods for Listeria monocytogenes or other potentially pathogen microorganisms are required. Furthermore, the human and animal reservoir role in the ecology of this disease must be established. Listeria spp. in the vizcacha intestinal content was determined by two isolation procedures, starting from 10 g of homogenized samples in 40 ml of PBS. I)0.1 ml was stripped on phenylethanol agar, selective agar for Listeria and acryflavin ceftazidin agar, then incubated at 37 degrees C for 48 h, suspected colonies were identified by preliminary tests (Gram, hemolysis, catalase, esculin hydrolisis and motility at 22 degrees C) and confirmatory tests (indol, methyl red, Voges Proskauer, nitrate and carbohydrate fermentation) (Table 1). Antibiotic susceptibility, protein profile by PAGE and pathogenic power in mice were determined. II) The remaining homogenate was incubated at 4 degrees C in 100 ml of Donnelly and Baigent enrichment broth, weekly or monthly with subcultures until 30 days or 6-8 months, respectively. The subcultures were followed up as in I). A L. seeligeri strain, susceptible to antibiotics suggested for L. monocytogenes and exhibiting resistance to some second and third generation cephalosporins, was isolated (Table 2). The protein profile of both species was coincident, but L. seeligeri was not virulent for mice. The finding of L. seeligeri in an animal (4.0

) used as human feeding source is of interest due to its potential pathogen power.

RESUMEN

In order to detect subclinical mastitis by means of California Mastitis Test and recounting of somatic cells, 163 cows from the dairies of San Luis city, Argentina, were examined. Seventy six individuals (46.6%) exhibited an inflammatory response ranging > or = 2+ grade and a cellular recounting value of > or = 5 x 10(5), data compatible with those of subclinical mastitis. Staphylococcus aureus was isolated from 39 (51.3%) cultures as estimated by the sum of the two last values listed in Table 1. Organisms were isolated by plating on brain heart infusion agar with 5% of sheep blood and on Baird-Parker media. One hundred and three S. aureus isolates recovered from 51 of 63 cows were characterized by coagulase activity by the tube method using human and bovine plasma; clumping factor; glucose and mannitol fermentation; thermonuclease (TNase), pigment, gelatinase, fibrinolysin, acetoin, hemolysin production; egg yolk, tellurite and catalase reaction and crystal violet types. All isolates were susceptible to cephalothin, clindamycin, methicillin, gentamycin and vancomycin; 94.1% were susceptible to chloramphenicol and 53.8% to G penicillin. Sixty three isolates (61.1%) were classified according to Hájek and Marsálek scheme as biotype C (bovine and ovine ecovar), 33 isolates (32.0%) were classified as biotype B (swine and poultry ecovar); 1 isolated (0.9%) as intermediate between B and D; 5 isolates (4.8%) as biotype A (human ecovar) and 1 isolated (0.9%) as biotype D (ecovar silvestres spp) (Table 2). Production of enterotoxins A to E and toxic shock syndrome toxin-1 (TSST-1) was determined by the optimal susceptibility plate method on 27 isolates (26.2%) which were coagulase 3+ to 4+ and TNase highly positive. None of them produced enterotoxins including TSST-1. The subclinical mastitis data and the prevalence of S. aureus coincide with those of other authors, both from Argentina and from other countries.

Asunto(s)

RESUMEN

In order to detect subclinical mastitis by means of California Mastitis Test and recounting of somatic cells, 163 cows from the dairies of San Luis city, Argentina, were examined. Seventy six individuals (46.6

) exhibited an inflammatory response ranging > or = 2+ grade and a cellular recounting value of > or = 5 x 10(5), data compatible with those of subclinical mastitis. Staphylococcus aureus was isolated from 39 (51.3

) cultures as estimated by the sum of the two last values listed in Table 1. Organisms were isolated by plating on brain heart infusion agar with 5

of sheep blood and on Baird-Parker media. One hundred and three S. aureus isolates recovered from 51 of 63 cows were characterized by coagulase activity by the tube method using human and bovine plasma; clumping factor; glucose and mannitol fermentation; thermonuclease (TNase), pigment, gelatinase, fibrinolysin, acetoin, hemolysin production; egg yolk, tellurite and catalase reaction and crystal violet types. All isolates were susceptible to cephalothin, clindamycin, methicillin, gentamycin and vancomycin; 94.1

were susceptible to chloramphenicol and 53.8

) were classified according to Hájek and Marsálek scheme as biotype C (bovine and ovine ecovar), 33 isolates (32.0

) were classified as biotype B (swine and poultry ecovar); 1 isolated (0.9

) as intermediate between B and D; 5 isolates (4.8

) as biotype A (human ecovar) and 1 isolated (0.9

) as biotype D (ecovar silvestres spp) (Table 2). Production of enterotoxins A to E and toxic shock syndrome toxin-1 (TSST-1) was determined by the optimal susceptibility plate method on 27 isolates (26.2

) which were coagulase 3+ to 4+ and TNase highly positive. None of them produced enterotoxins including TSST-1. The subclinical mastitis data and the prevalence of S. aureus coincide with those of other authors, both from Argentina and from other countries.

RESUMEN

In order to detect subclinical mastitis by means of California Mastitis Test and recounting of somatic cells, 163 cows from the dairies of San Luis city, Argentina, were examined. Seventy six individuals (46.6

) exhibited an inflammatory response ranging > or = 2+ grade and a cellular recounting value of > or = 5 x 10(5), data compatible with those of subclinical mastitis. Staphylococcus aureus was isolated from 39 (51.3

) cultures as estimated by the sum of the two last values listed in Table 1. Organisms were isolated by plating on brain heart infusion agar with 5

of sheep blood and on Baird-Parker media. One hundred and three S. aureus isolates recovered from 51 of 63 cows were characterized by coagulase activity by the tube method using human and bovine plasma; clumping factor; glucose and mannitol fermentation; thermonuclease (TNase), pigment, gelatinase, fibrinolysin, acetoin, hemolysin production; egg yolk, tellurite and catalase reaction and crystal violet types. All isolates were susceptible to cephalothin, clindamycin, methicillin, gentamycin and vancomycin; 94.1

were susceptible to chloramphenicol and 53.8

) were classified according to Hájek and Marsálek scheme as biotype C (bovine and ovine ecovar), 33 isolates (32.0

) were classified as biotype B (swine and poultry ecovar); 1 isolated (0.9

) as intermediate between B and D; 5 isolates (4.8

) as biotype A (human ecovar) and 1 isolated (0.9

) as biotype D (ecovar silvestres spp) (Table 2). Production of enterotoxins A to E and toxic shock syndrome toxin-1 (TSST-1) was determined by the optimal susceptibility plate method on 27 isolates (26.2

) which were coagulase 3+ to 4+ and TNase highly positive. None of them produced enterotoxins including TSST-1. The subclinical mastitis data and the prevalence of S. aureus coincide with those of other authors, both from Argentina and from other countries.

RESUMEN

In order to detect subclinical mastitis by means of California Mastitis Test and recounting of somatic cells, 163 cows from the dairies of San Luis city, Argentina, were examined. Seventy six individuals (46.6

) exhibited an inflammatory response ranging > or = 2+ grade and a cellular recounting value of > or = 5 x 10(5), data compatible with those of subclinical mastitis. Staphylococcus aureus was isolated from 39 (51.3

) cultures as estimated by the sum of the two last values listed in Table 1. Organisms were isolated by plating on brain heart infusion agar with 5

of sheep blood and on Baird-Parker media. One hundred and three S. aureus isolates recovered from 51 of 63 cows were characterized by coagulase activity by the tube method using human and bovine plasma; clumping factor; glucose and mannitol fermentation; thermonuclease (TNase), pigment, gelatinase, fibrinolysin, acetoin, hemolysin production; egg yolk, tellurite and catalase reaction and crystal violet types. All isolates were susceptible to cephalothin, clindamycin, methicillin, gentamycin and vancomycin; 94.1

were susceptible to chloramphenicol and 53.8

to G penicillin. Sixty three isolates (61.1

) were classified according to Hájek and Marsálek scheme as biotype C (bovine and ovine ecovar), 33 isolates (32.0

) were classified as biotype B (swine and poultry ecovar); 1 isolated (0.9

) as intermediate between B and D; 5 isolates (4.8

) as biotype A (human ecovar) and 1 isolated (0.9

) as biotype D (ecovar silvestres spp) (Table 2). Production of enterotoxins A to E and toxic shock syndrome toxin-1 (TSST-1) was determined by the optimal susceptibility plate method on 27 isolates (26.2

) which were coagulase 3+ to 4+ and TNase highly positive. None of them produced enterotoxins including TSST-1. The subclinical mastitis data and the prevalence of S. aureus coincide with those of other authors, both from Argentina and from other countries.

RESUMEN

In order to detect subclinical mastitis by means of California Mastitis Test and recounting of somatic cells, 163 cows from the dairies of San Luis city, Argentina, were examined. Seventy six individuals (46.6

) exhibited an inflammatory response ranging > or = 2+ grade and a cellular recounting value of > or = 5 x 10(5), data compatible with those of subclinical mastitis. Staphylococcus aureus was isolated from 39 (51.3

) cultures as estimated by the sum of the two last values listed in Table 1. Organisms were isolated by plating on brain heart infusion agar with 5

of sheep blood and on Baird-Parker media. One hundred and three S. aureus isolates recovered from 51 of 63 cows were characterized by coagulase activity by the tube method using human and bovine plasma; clumping factor; glucose and mannitol fermentation; thermonuclease (TNase), pigment, gelatinase, fibrinolysin, acetoin, hemolysin production; egg yolk, tellurite and catalase reaction and crystal violet types. All isolates were susceptible to cephalothin, clindamycin, methicillin, gentamycin and vancomycin; 94.1

were susceptible to chloramphenicol and 53.8

to G penicillin. Sixty three isolates (61.1

) were classified according to Hájek and Marsálek scheme as biotype C (bovine and ovine ecovar), 33 isolates (32.0

) were classified as biotype B (swine and poultry ecovar); 1 isolated (0.9

) as intermediate between B and D; 5 isolates (4.8

) as biotype A (human ecovar) and 1 isolated (0.9

) as biotype D (ecovar silvestres spp) (Table 2). Production of enterotoxins A to E and toxic shock syndrome toxin-1 (TSST-1) was determined by the optimal susceptibility plate method on 27 isolates (26.2

) which were coagulase 3+ to 4+ and TNase highly positive. None of them produced enterotoxins including TSST-1. The subclinical mastitis data and the prevalence of S. aureus coincide with those of other authors, both from Argentina and from other countries.

RESUMEN

In order to determine the sanitary quality of ice-creams and the presence of pathogenic or potentially pathogenic species of Salmonella and Yersinia enterocolitica, 50 samples from 5 different industrial and semi-industrial producers in San Luis (Argentine) were examined. The enumeration of coliforms was positive for all the samples with values less than or equal to 20/g. Fourteen per cent of the samples were positive for the investigation of Staphylococcus aureus in 1 g. For the plates enumeration 12.0% of the samples gave less than 10 u.f.c./g, 4.0% between 101 and 1000 and 4.0% between 1001 and 10,000. Fifteen strains were isolated, 26.6% biotype A (human ecovar) and the others biotype C (bovine ecovar). All of them were susceptible to chloramphenicol, cephalosporin and erythromycin; 46.6% to penicillin G and ampicillin; 93.3% to kanamycin (6.6% intermediate ones = I); 73.3% to methicillin (26.6% I); 86.6% to tetracycline (13.3% I). Six per cent of the samples over came the acceptability limit for S. aureus. Salmonella spp was not isolated. In 4.0% of the samples Y. enterocolitica were isolated, one of them typified as B1; 0:3, 50, 51, Lis Xz. The latter, isolated in samples with values of coliforms inferior to the limit fixed by some legislations, suggests a post elaboration contamination.

Asunto(s)

RESUMEN

In order to determine the sanitary quality of ice-creams and the presence of pathogenic or potentially pathogenic species of Salmonella and Yersinia enterocolitica, 50 samples from 5 different industrial and semi-industrial producers in San Luis (Argentine) were examined. The enumeration of coliforms was positive for all the samples with values less than or equal to 20/g. Fourteen per cent of the samples were positive for the investigation of Staphylococcus aureus in 1 g. For the plates enumeration 12.0

of the samples gave less than 10 u.f.c./g, 4.0

between 101 and 1000 and 4.0

between 1001 and 10,000. Fifteen strains were isolated, 26.6

biotype A (human ecovar) and the others biotype C (bovine ecovar). All of them were susceptible to chloramphenicol, cephalosporin and erythromycin; 46.6

to penicillin G and ampicillin; 93.3

to kanamycin (6.6

intermediate ones = I); 73.3

to methicillin (26.6

I); 86.6

to tetracycline (13.3

I). Six per cent of the samples over came the acceptability limit for S. aureus. Salmonella spp was not isolated. In 4.0

of the samples Y. enterocolitica were isolated, one of them typified as B1; 0:3, 50, 51, Lis Xz. The latter, isolated in samples with values of coliforms inferior to the limit fixed by some legislations, suggests a post elaboration contamination.