IgG antibodies against phospholipase A2 from Crotalus durissus terrificus: cross-reaction with venoms from Bothrops species from Argentina

We examined the ability of IgG anti-crotalic PLA2 to cross-react with Bothrops spp. venoms, from snakes found in the northeast of Argentina. Immunoblotting and ELISA tests showed that IgG anti-crotalic PLA2 recognize antigens of bothropic venoms. Indirect hemolytic activity tests showed that the quantity of antibodies that neutralized 50% of Crotalus durissus terrificus venom (ED50: 2.1 mg IgG anti-crotalic PLA2/100 µg of venom) were also able to neutralize venom from other snakes in the following proportion: 34% of B. alternatus, 18% of B. diporus and 12% of B. jararacussu. Likewise, direct PLA2 activity neutralization tests showed a similar cross-neutralization pattern including 56% of B. alternatus, 29% of B. diporus and 30% of B. jararacussu. In addition, in a myotoxic activity neutralization test, measured by plasma activity of creatine kinase, 35% of B. alternatus venom and 26% of B. diporus venom were neutralized, while no neutralization was detected with B. jararacussu venom. This study presents original data concerning cross-reactions between bothropic venoms from Argentina and IgG anti-crotalic PLA2. Our results suggest that anti-crotalic PLA2 antibodies should not be used to neutralize PLA2 activity of B. alternatus, B. diporus and especially B. jararacussu venoms; nor to enrich commercial antivenoms against these Bothrops species.(AU)

Partial characterization of enterocin MR99 from a corn silage isolate of Enterococcus faecalis.

AIMS: To assess the inhibitory activity on Gram-positive and Gram-negative bacteria of several species of enterococci recovered from a natural corn silage. METHODS AND RESULTS: The inhibitory activity of strains of Enterococcus faecalis (58), Enterococcus faecium (35), Enterococcus gallinarum (3) and Enterococcus casseliflavus (4) were studied employing indicator strains from various sources (clinical, food and ATCC). Enterococcus faecalis MR99, the only strain with inhibitory activity, inhibited other enterococci, Listeria spp., Staphylococcus aureus, Clostridium spp., Bacillus spp., Escherichia coli, Shigella sonnei and Shigella flexneri. The bacterium contained only one conjugative pheromone-responsive plasmid. The partially chromatography-purified MR99 enterocin (PPE) had a molecular weight of approx. 5000 Da and a pI of 6.2, was sensitive to proteolytic enzymes and could be extracted in benzene and butanol. It appeared stable to adjustment of pH 4.0, 5.0, 6.0, 7.0 and 8.0 and was resistant to heat. Inactivation was at 15 min at 121 degrees C. Enterocin MR99 was bactericidal on strains of Listeria monocytogenes, Staph. aureus, and bovine mastitis agents, it was bacteriostatic on E. coli. Although enterocins MR99 and AS48 have inhibitory activity on Gram-negative bacilli, PCR studies demonstrated a lack of relationship between them. CONCLUSIONS: The active component had a protein nature, was resistant to heat and presented a wide inhibitory spectrum. SIGNIFICANCE AND IMPACT OF THE STUDY: The biological properties of Ent. faecalis MR99 suggest that this strain merits further investigations so it can be applied in human and veterinary health programmes.

Clinical status and parasitic infection in a Wichí Aboriginal community in Salta, Argentina.

In a study, carried out in 2000, of the clinical and parasitological status of a Wichi Aboriginal community living in the suburbs of Tartagal, northern Salta, Argentina, 154 individuals were screened for parasitic infections. Ninety-five faecal samples were also obtained from the same population. Ninety-three percent of the subjects were positive for 1 or more of the parasites investigated by direct test and 70.5% of them had parasitic superinfection. The most frequent helminths were Strongyloides stercoralis (50.5%) and hookworm (47.4%). We found low reinfection rates and a long reinfection period after treatment and provision of safe water and sanitation. Serum reactivity of these patients was analysed by enzyme-linked immunosorbent assay and indirect immunofluorescent assay and 22.1% of them had anti-Toxocara antibodies, 16.2% were positive for a complex antigen of Leishmania braziliensis, 29.9% were positive for a complex Trypanosoma cruzi antigen, and 17.5% were positive for a specific Trypanosoma cruzi antigen, Ag 163B6/cruzipain.

[Zoonotic parasitosis transmitted by dogs in the Chaco Salteño, Argentina]. / Parasitosis zoonóticas transmitidas por perros en el Chaco Salteño.

Toxocara canis and Ancylostoma spp. are geohelmints that parasites dogs and can eventually affect humans, mainly children, causing visceral and cutaneous larva migrans respectively, constituting a serious public health problem. This study was carried out in two towns located in the xerophilous forest Chaco salteño where humans live closely with many animals, including dogs. Hematological values and anti-Toxocara canis antibodies, determined by ELISA in serum, were evaluated in 98 children from this area. Thirty-six children presented with eosinophilia of 10% or higher in peripheral blood. Twenty out of 98 (20.4%) children had antibodies against antigen from L2 larvae of Toxocara canis. A high percentage (55.6%) of the children with eosinophilia presented anti-Toxocara canis antibodies. Nine children had multiple serpiginous lesions typical of cutaneous larva migrans. Feces from dogs were collected in the area where children lived, in order to search for parasite contamination. Three different techniques of stool examination were employed and eggs were counted. Out of the 106 feces examined, parasites were found in 82 samples (77.4%). Ancylostoma spp eggs were found in 74 (69.8%) samples and eggs from Toxocara canis were found in 19 (17.2%). The average number of T. canis and Ancylostoma spp eggs/gr of feces, were 200 and 3,871 respectively. Giardia spp (14.5%), Trichuris vulpis (7.6%), Genus Endamoeba (2.8%) and Taenia spp (1.9%) were also identified in the stools. Sanitary control and health education in order to control these parasitoses are emphasized.

Parasitosis zoonóticas transmitidas por perros en el Chaco Salteño. / [Zoonotic parasitosis transmitted by dogs in the Chaco Salteño, Argentina]

Toxocara canis and Ancylostoma spp. are geohelmints that parasites dogs and can eventually affect humans, mainly children, causing visceral and cutaneous larva migrans respectively, constituting a serious public health problem. This study was carried out in two towns located in the xerophilous forest Chaco salteño where humans live closely with many animals, including dogs. Hematological values and anti-Toxocara canis antibodies, determined by ELISA in serum, were evaluated in 98 children from this area. Thirty-six children presented with eosinophilia of 10

or higher in peripheral blood. Twenty out of 98 (20.4

) children had antibodies against antigen from L2 larvae of Toxocara canis. A high percentage (55.6

) of the children with eosinophilia presented anti-Toxocara canis antibodies. Nine children had multiple serpiginous lesions typical of cutaneous larva migrans. Feces from dogs were collected in the area where children lived, in order to search for parasite contamination. Three different techniques of stool examination were employed and eggs were counted. Out of the 106 feces examined, parasites were found in 82 samples (77.4

). Ancylostoma spp eggs were found in 74 (69.8

) samples and eggs from Toxocara canis were found in 19 (17.2

). The average number of T. canis and Ancylostoma spp eggs/gr of feces, were 200 and 3,871 respectively. Giardia spp (14.5

), Trichuris vulpis (7.6

), Genus Endamoeba (2.8

) and Taenia spp (1.9

) were also identified in the stools. Sanitary control and health education in order to control these parasitoses are emphasized.