[Bacteriologic analysis and detection of Clostridium botulinum spores in honey]. / Análisis bacteriológico e investigación de esporas de Clostridium botulinum en mieles.

The bacteriological analysis and, particularly, the detection of Clostridium botulinum spores from 42 honey samples collected in apiaries of the province of San Luis as well as neighbouring areas of La Pampa, Córdoba and Mendoza, were carried out. Samples were processed by the dilution and centrifugation procedures. For spores detection, culture of the pellets were performed in 2 tubes with cooked meat medium (MCC), one of them warmed up to 80 degrees C for 15 min, and both incubated at 30 degrees C during 7 days. Mice were used to search for toxin in the supernatant. Sediments were also searched for anaerobic bacteria detection in yolk agar plates and in nutritive agar plates for the aerobics. Botulinum toxin type A production was found in one of the MCC cultures. No anaerobic bacteria were isolated. All samples contained Bacillus spp.; 21.4% of the strains, were tentatively classified as B. alvei. A working model for the bacteriological analysis of honey and guides that could be enclosed in publications of official institutions (Figure 1) is proposed.

[Isolation of Listeria seeligery from cecum of vizcacha (Lagostomus maximus maximus)]. / Aislamiento de Listeria seeligeri de ciego de vizcacha (Lagostomus maximus maximus).

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.

[Detection of Clostridium botulinum spores in honey]. / Detección de esporas de Clostridium botulinum en mieles.

A total of 177 honey samples were examined for Clostridium botulinum, 68 of which were from commercial origin, 8 from small rural producers for family consumption, and the remaining 6 from fractionizing centers in Mendoza and San Luis provinces in Argentina. C. botulinum type A was detected in two samples of rural producer origin (1.1%) by the centrifugation-dilution method. The strain was recovered from one of the samples, obtaining a spore count of 55/g of honey. Even though the positive percentage was lower than that found in other countries, honey consumption by children under one year old should be avoided in order to prevent infant botulism.

[Determination of the sanitary quality and detection of Salmonella spp and Yersinia enterocolitica in ice cream]. / Determinación de la calidad higiénica e investigación de Salmonella spp y Yersinia enterocolítica en helados.

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.

Rapid in vivo assay method for type G botulinal toxin.

The survival time (ST) dose-response curve for Clostridium botulinum type G toxin was determined in mice and evaluated as a rapid assay method. As it occurs with other botulinal toxin types, the results showed a linear relationship between the logarithm of the injected dose and the logarithm of ST. The slope of the ST dose-response curve for type G toxin differed significantly from those for type A or subtype Af toxins. This parameter was altered when trypsin-activated type G toxin was used. The ST dose-response curve was rather stable. This in vivo assay method could be applied for the estimation of the potency of G toxin preparations in a short time using only some few mice.

Análisis bacteriológico e investigación de esporas de Clostridium botulinum en mieles / [Bacteriologic analysis and detection of Clostridium botulinum spores in honey]

The bacteriological analysis and, particularly, the detection of Clostridium botulinum spores from 42 honey samples collected in apiaries of the province of San Luis as well as neighbouring areas of La Pampa, Córdoba and Mendoza, were carried out. Samples were processed by the dilution and centrifugation procedures. For spores detection, culture of the pellets were performed in 2 tubes with cooked meat medium (MCC), one of them warmed up to 80 degrees C for 15 min, and both incubated at 30 degrees C during 7 days. Mice were used to search for toxin in the supernatant. Sediments were also searched for anaerobic bacteria detection in yolk agar plates and in nutritive agar plates for the aerobics. Botulinum toxin type A production was found in one of the MCC cultures. No anaerobic bacteria were isolated. All samples contained Bacillus spp.; 21.4

of the strains, were tentatively classified as B. alvei. A working model for the bacteriological analysis of honey and guides that could be enclosed in publications of official institutions (Figure 1) is proposed.

Aislamiento de Listeria seeligeri de ciego de vizcacha (Lagostomus maximus maximus) / [Isolation of Listeria seeligery from cecum of vizcacha (Lagostomus maximus maximus)]

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.