Biomedical subjects
Publications and source records attributed to D F Giménez.
The serological identification of Clostridium botulinum neurotoxin (BoNT) subtypes has shown to be elusive when current standard serologic tests are used. Based on (1) the in vivo response expected on quantitative BoNT-antitoxin systems and (2) the actual and the hypothetical antigenic makeup of BoNT subtypes, a comprehensive method for BoNTs typing is proposed.
Thirty-six Staphylococcus aureus isolates recovered from 35 of 204 young goats at slaughter were characterized. All isolates were susceptible to cephalothin, clindamycin, chloramphenicol, gentamicin, kanamycin, and amikacin. All but 2 were susceptible to erythromycin and tetracycline, and 19 and 20 were susceptible to penicillin and ampicillin, respectively. Thirteen isolates were classified as biotype A, 9 isolates were classified as biotype B, 8 isolates were classified as biotype C, and 6 isolates were classified as intermediate between B and C or were not biotypable. Six biotype A isolates were enterotoxigenic; 4 produced enterotoxin B, 1 produced enterotoxin C, and 1 produced enterotoxin D. Two biotype B strains produced enterotoxin B, and all 8 biotype C isolates produced enterotoxin C and the toxic shock syndrome toxin-1.
The production of a protein insoluble at low temperature ("cryoprotein"), by cultures of Clostridium botulinum type G has been shown to be a metabolic characteristic also shared by C. botulinum type C and by C. subterminale. These new cryoproteins have been purified and some of their chemical and immunological properties studied. It was found that both proteins were chemically very similar among themselves and to the cryoprotein isolated from C. botulinum type G. All these proteins are formed by a single polypeptide chain of approximately Mr = 180,000, with closely related amino acid compositions, isoelectric points and do not contain either free cysteine or disulfide bridges. Homologous and heterologous radioimmunoassays established the existence of an antigenic similitude among the cryoproteins from C. botulinum type G and C. subterminale thus becoming the first purified antigens which relate both bacterial species. If the production of cryoproteins can be shown to be a generalized phenomenon within the genus Clostridium these substances would provide an important tool to examine immunological and genetical relatedness between strains in this bacterial group.
In December 1982 an outbreak of foodborne botulism presumably produced by the ingestion of home-made pickled trout occurred in San Rafael, province of Mendoza, Argentina. The toxin detected in blood serum and feces samples of the sole affected patient was preliminarily typed as a plain type A. A strain of Clostridium botulinum was isolated from feces which, after culture by the dialysis method, produced 1 x 10(7) LD50/mouse per ml. Quantitative neutralization tests carried out at different levels of toxin concentration, showed that this toxin consists of a major type A antigenic component (about 99% of the complex) and a minor type F component, defining its identity as a subtype Af. A rabbit antiserum obtained from this toxin neutralizes A and F reference toxins. Despite the antitoxic and supportive treatment, the patient died as a consequence of the poisoning. The polyvalent antiserum administered contained A, B and E antitoxins. Death could be due to the lethal effect of the A fraction, the F fraction or to a combined effect of both toxic components of the toxin. This is the first detection of an outbreak produced by C. botulinum subtype Af, serotype described in Argentina fifteen years ago, and not detected until now in other parts of the world.(ABSTRACT TRUNCATED AT 250 WORDS)
Enterotoxigenicity, virulence and antimicrobial susceptibility were studied in thirteen strains of Yersinia enterocolitica isolated from meat foods and organs of slaughtered animals. The following biotypes (B), serotypes (O) and lisotypes (Lis) were studied: B2, O:9, Lis X3 and B1, O:7,8, Lis Xo (from thick fresh sausages); B1, O:5, Lis Xz (from slender sausages); B1, O:5, Lis Xz and B2, O:9, Lis X3 (from bovine tongues); B1, O:6, Lis Xz (from porcine tongues) and B1, O:6, Lis Xz (from porcine caeca) (Table 1). Virulence was determined by i) the autoagglutination test (Laird and Cavanaugh), replacing in the Eagle medium amino acids and vitamins with proteose peptone (1%), tryptone (1%) and yeast extract (0.5%), and ii) the calcium dependency test. The LD50 of five strains was determined by i.p. injection of O.5 ml of cell suspensions into white mice and estimated by the Spearman Kärber method. LD50 varied from 2 x 10(9) to 7 x 10(9) viable cells per ml. The enterotoxigenicity test was carried out in suckling white mice and the invasiveness test (Sereny) in adult white mice. Two strains showed autoagglutination, five calcium dependency, two were invasive and eight produced enterotoxin. Antimicrobial susceptibility was assayed by the modified Kirby and Bauer test. All the strains were susceptible to kanamycin, amikacin, cefotaxime, cefuroxime, chloramphenicol, fosfomycin, mezlocillin, nitrofurantoin, piperacillin, piperimidic acid, polymyxin B, sisomycin and tobramycin, and resistant to cephalotoxin, ampicillin and trimethoprim-sulfamethoxazole.(ABSTRACT TRUNCATED AT 250 WORDS)
Strain 657 has been described as a toxin variant of Clostridium botulinum type B. Neutralization tests performed with types A and B botulinal antitoxins of known potency and avidity at 20, 25, 50, 100, 200, 2,000 and 20,000 mouse LD50 levels of testing, have shown that 657 toxin is a mixture of B (approximately 95% of the complex) and A antigenic fractions. The possibility of a cross-contamination between A and B serotypes has been practically ruled out through the serologic screening of the toxins from 100 well isolated colonies taken from two colony variants of this strain. Strain 657 rabbit antitoxin possesses A and B neutralizing activities. Strain B 657 produces a hitherto undescribed complex toxin and it represents the prototype of a new C. botulinum serotype, subtype Ba.
A search for Y. enterocolitica in fresh foods of animal origin has been carried out. Isolations were obtained from "chorizos" (thick fresh sausages), "salchichas" (slender fresh sausages), bovine and pig's tongues and caecum (Tables 1, 2). Enrichments were performed in saline phosphate buffer 0.067 M, pH 7.6 and nutrient broth with 0.5% glucose. Caecum and tongue samples were postenriched in 0.5% KOH. Subcultures were done in Salmonella-Shigella agar, MacConkey agar and eosin-methylene blue agar. Isolates were identified through biochemical, serological and lysotyping methods. The following biotypes (B), serotypes (O) and lysotypes (Lis) were isolated: from "chorizos", B2, 0:9, Lis X3 and B1, 0:7,8, Lis Xo. From "salchichas", B1, 0:5, Lis Xz. From bovine tongues, B1, 0:5, Lis Xz and B2, 0:9, Lis X3. From pig tongues, B1, 0:6, Lis Xz. From pig caecum, B1, 0:6, Lis Xz and B1, 0:5, Lis Xz. Serotype B2, 0:9, Lis X3 isolated from "chorizos" and bovine tongues has been only exceptionally found outside of human beings. Serotype B1, 0:6, Liz Xz was isolated from the tongue and caecum of one pig. From the caecum of another pig two serotypes, B1, 0:5, Liz Xz and B1, 0:6, Liz Xz, were isolated. In order to determine the importance of Y. entercolitica as etiologic agent of yersiniosis in Argentina, further studies on the frequency and distribution of this agent are recommended.
Strain 657 has been described as a toxin variant of Clostridium botulinum type B. Toxin neutralization tests performed with types B and A botulinum antitoxins of known potency, avidity and specificity at 20, 200, 2.000 and 20.000 DL50/mouse level of testing have shown that 657 toxin is a mixture of B (90 to 99% of the complex) and A antigenic fractions. The possibility of a cross contamination between A and B serotypes has been, in principle, ruled out through the serologic screening of 33 toxin samples coming one each from 33 well isolated colonies taken from two colony variants of this strain. Strain 657 produces a new complex toxin and is proposed as the candidate for the prototype of a new C. botulinum serotype: subtype Ba.
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Two new strains of Clostridium botulinum subtype Af have been isolated from soil samples of Mendoza Province, Argentina. Some serological and other biological properties of these new isolates have been studied in comparison with the prototype 84-SC2 strain. No differences in morphology and biochemical activities were found among these three so far known strains of this subtype. Neither serologic differences have been recorded, suggesting that the bispecificity and the type A to type F serologic ratio (A:F) is a stable genetic trait of subtype Af. The three strains were found in well separated areas. None of the type A strains isolated either from soil samples or from human botulism outbreaks in Mendoza have shown such a high degree of toxigenicity as that shown by Af strains. All these facts suggest that this peculiar type is not the product of a recent genetic relationship between types A and F. Rather, it represents a stable type in nature.
Serological classification of Cl. botulinum, based on the antigenic structure of the toxins produced, is distinguished by the behaviour of the toxin-antitoxin mixtures in in vivo neutralization tests. Observations on the dissimilarity between strains within types, the behaviour of antitoxins in the cross-neutralization tests, the established concepts of the antigenic structure of the toxin types and the lack of a standard methodology for typing, have led to the definition of the terms efficiency, type, subtype, intratypic serological variant (ISV), and degree of serological homology. These definitions are primarily applied to typing and to the establishment of the taxonomic serological categories of type, subtype and ISV. In the case of antitoxin standardization, the accepted standard methods must be followed.
Strain 89 of Clostridium botulinum type G produces a protein which behaves as a cryoprotein.
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One strain of Clostridium botulinum belonging to type F has been isolated from a soil sample taken in Buenos Aires Province, Argentina. Comparative studies carried out with strain Langeland of C. botulinum type F have shown a few differences between the two strains.
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Bacteriological studies were carried out on several necropsy samples from five animals whose deaths had been attributed to bovine botulism. This disease, regionally called Mal de Aguapey, enzootically affects animals from a wide area of the north-east of Argentina (Province of Corrientes) with a bovine population estimated at near to 2,500,000. Either C. botulinum type D, its toxin or both were identified in all animal samples, alternatively in contents of rumen, jejunum, ileum, caecum and in samples of spleen, liver and kidney (Table 1). C. botulinum type A was isolated respectively from the liver and the kidney of two animals. Cultures of 100 soil samples taken in the enzootic area were positive only for C. botulinum type A (3%). These results enlarge and confirm previous findings and lend support to the botulinic etiology of the Mal de Aguapey.