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Biomedical subjects

J A Valdivia Alvarez

Publications and source records attributed to J A Valdivia Alvarez.

At least 19 recordsLinked to original sources
PubMed1996

[Taxonomic study of species of the Mycobacterium genus isolated in Cuba].

40 strains of the Mycobacterium genus corresponding to 12 species, which were subjected to 62 microbiological and biochemical tests, were studied. Each one was considered as a character. As a result of the similitude coefficient and their grouping, 9 phenomes represented by: Phenome I (Mycobacterium fortuitum), Phenome II (MAI Complex), Phenome III (Mycobacterium phlei), Phenome IV (Mycobacterium triviale), Phenome V (Mycobacterium smegmatis), Phenome VI (Mycobacterium gordonae), Phenome VII (Mycobacterium szulgai), Phenome VIII (MAI Complex), and Phenome IX (Mycobacterium scrofulaceum), were obtained. The strain identification work was consistent with grouping from the phenotypic point of view.

Cuba↗
PubMed1995

[A susceptibility study of Mycobacterium avium-intracellulare strains using the broth macrodilution method].

The macrobroth dilution method was used for determining the resistance and/or sensitivity of 10 nontuberculous mycobacteria strains from Mycobacterium avium-intracellulare (MAI) complex isolated from patients presenting with respiratory symptoms. Drugs employed were as follows: isoniazid, ethambutol, rifampicin, streptomycin, gentamicin and amikacin. With respect to susceptibility of the strains studied, the greater sensitivity was found to be against ethambutol, amikacin, and gentamicin. The possibility of replacing the Middlebrook 7H9 liquid culture medium by the UIT-L liquid culture medium was analyzed. Normalization of the method was attained and a shortening of the reading time when using the UIT-L culture medium was also obtained.

Anti-Bacterial Agents↗
PubMed1995

[The identification of Mycobacterium tuberculosis strains using paper strips for the niacin technic].

Mycobacterium tuberculosis strains were identified using paper strips for niacin technique; these paper strips were made at the National Reference Laboratory on Tuberculosis and Mycobacteria of the IPK. Results were compared with the conventional niacin technique and a 100% of coincidence was obtained; advantages, sensitivity and firmness of this method are reported.

Bacteriological Techniques↗
PubMed1995

[A growth supplement for "fastidious germs"].

A growth supplement for "fastidious germs" was produced at the Laboratory of Acute Respiratory Infections of "Pedro Kourí" Institute of Tropical Medicine. This supplement was studied by computerized optic spectrophotometry, and chemical composition was determined. The efficacy of this supplement for the culture of Haemophilus influenzae type b, was evidenced using 100 strains, and it was proven that it can be used in concentrations raging from 1 to 10%.

Animals↗
PubMed1992

[Identification of strains of beta-hemolytic streptococci of groups A, B, C, and G by coagglutination].

A study was conducted on the coagglutination (CoA) technique in the serogrouping of betahemolytic streptococci of the groups A, B, C and G, previously identified by physiological tests and the agar immunodiffusion technique. This technique was used as a reference test and, according to its results, it can be stated that the CoA technique allowed for the serological grouping in 95.7% of the strains. The CoA technique was assessed by using reactions prepared in our laboratories and the commercial kit Phadebact.

Agglutination↗
PubMed1992

[Phage typing of Mycobacterium tuberculosis using the overlay technique. Preliminary study].

One hundred and fifty strains of Mycobacterium tuberculosis were classified by the phagotyping technique, using the double layer method described by Adams and modified by Jones. The efficacy of this method was studies in comparison with the method claimed by Redmond and Ward and traditionally employed for Mycobacteria typing. Preliminary Results obtained have allowed to prove its advantages. A 96% of coincidence with respect to the traditional method was reported.

Bacteriophage Typing↗
PubMed1992

[Non-tuberculous mycobacteria isolated in Cuba during the 1985-1989 period. Preliminary report].

A number of 1,061 strains of nontuberculous mycobacteria referred to "Pedro Kouri" Institute of Tropical Medicine during the period of 1985-1989 were studied. Strains were from Provincial Centers of Hygiene and Epidemiology of the country. According to the results obtained, most of the strains classified are found in groups III and IV according to the criteria of Runyon (54, 76, and 36%, respectively). Species with a greater frequency belong to the complex MAI and M. fortuitum.

Humans↗
PubMedDate not supplied

[Evaluation of the pyrazinamidase test for the detection of susceptibility of Mycobacterium tuberculosis to pyrazinamide].

The pyrazinamidase test was used to determine susceptibility to pyrazinamide in 55 strains of Mycobacterium tuberculosis received at the National Laboratory of Reference and Research of Tuberculosis and Mycobacteria of the "Pedro Kourí" Institute of Tropical Medicine during the first semester of 1997. On comparing the results obtained with the method of proportions, it was attained a correlation of 83.6% of sensitivity with 16.4% of false positives. It was proved that the pyrazinamidase test should not replace the method of proportions.

Amidohydrolases↗
PubMedDate not supplied

[Phage typing of Mycobacterium tuberculosis strains coming from Nicaragua (preliminary report)].

Fifty Nicaraguan strains of Mycobacterium tuberculosis were classified with a scheme of 9 specific phages. A preliminary distribution of characteristic phagotypes of the area is reported, with prevalence of phagotype I (intermedial) (66%), presence of phagotype A (34%) and absence of the rest of the types. Inclusions of phagotypes Bo4 and F-o-WJ within the classification scheme, as well as practical usefulness of the technique in studies directed to disease control, are valued.

Bacteriophage Typing↗
PubMedDate not supplied

[Serotyping of strains of non-tuberculous mycobacteria].

Forty strains of mycobacteria, belonging to Mycobacterium-avium-intracellulare-scrofulaceum complex, isolated from symptomatic respiratory patients, were studied. For such study, agglutination-adsorption technique was applied, using specific antisera elaborated at the "Pedro Kouri" Institute of Tropical Medicine, National Reference Institute, with titers ranging close to 1:320. The results obtained demonstrated that the prevailing types were those of the species Mycobacterium intracellulare (31 strains), prevailing serotypes 9 (Darden), 8 (Davis), 12 (Haweel) and serotype 26 followed by the species M. avium (3 strains) and M. scrofulaceum (2 strains).

Cuba↗
PubMedDate not supplied

[Study using phagetype markers of Mycobacterium tuberculosis strains from Ethiopia. A preliminary study].

Twenty strains of Mycobacterium tuberculosis from Addis Ababa (Ethiopia) are studied by means of the phage typing technique in mycobacteria. The results obtained show the preliminary distribution of phage types belonging to type I (intermediate) and absence of the remaining types. The lysis pattern of autochthonous M. tuberculosis is characterized by a prevalence of sensitivity to phages DS6A, GS4E, BG1, and D34. The early results of sensitivity obtained with phage Bo4 and its assessment within the current scheme for M. tuberculosis classification.

Bacteriophage Typing↗