Revista de la Asociacion Argentina de Microbiologia最新文献

The effects of the addition of ground maize straw, nitrogen compounds, ground lucern and water to soils incubated at 30 degrees C in Erlenmeyer flasks, on Azotobacter chroococcum growth have been studied. The results showed that the highest number of Azotobacter in soils treated with different percentage of ground maize straw without addition of nitrogen compounds and with water at 100% field capacity appeared as soon as the 5th day, reaching a maximun on the 20th day when the following numbers of bacteria were observed: control, 1,5 times 20(6); straw 1% 30 times 10(6), 2%, 33 times 10(6) and 4%, 77 times 10(6) per gram of air dried soil. This enables us to assume that the anaerobic decomposition of straw (cellulose and hemicellulose principally) in nature leads to the indirect utilization of its energy for a high asymbiotic microbiogical soil fixation of atmospheric nitrogen.

The results obtained by the immunoelectrophoresis (IEP) aand Casoni intradermal (IDR) tests in a group of 50 hydatidosis patients in which the presence of cysts was later confirmed at surgery, are analyzed. The sensitivity of the IEP test was 74%; the IDR test was positive in 54% of these patients and there was no correlation between the results of the two tests in 24% of the cases. The low sensitivity observed for the IDR test, its known nonspecificity and its poor correlation with IEP test results do not enable us to recommend its use for the diagnosis of hydatid disease or for the selection of cases in which an immunodiagnostic confirmation is feasible. This recommendation would be possible if appropriate antigens regarding specificity and reactivity were available, and could be employed with standardized methods to read and evaluate cutaneous reactivity.

The influence of culture medium composition on alkaline protease production was studies. Various carbon sources such as glycerol, glucose, lactose and starch were tested. Different concentrations of lactose and bactopeptone have been tested. The optimum medium composition was found to be: (g/l) lactose 20.0; bactopeptne Difco 10.0; NaCl 1.5;mgSO47.H20 0.15; CaCl2 0.06; K2HPO4 1.5; KH2PO4 1.5; Na2SO4 1.5; MnCL2.4H2O 0.01. A cell concentration of c.a 9.5 g/l has been obtained after 30 hours. The maximun alkaline protease production (5,000 uAPAM/ml) was attained after 60 hours. The trials were carried on rotary shaker in 1 liter erlenmeyer flasks containing 250 ml of medium.

This work deals with different groups of microorganisms in the polluted water of the fishery section of Mar del Plata harbour and in the way followed by the fisher's boats. Bacteriological determinations were: total count, MPN of coliforms, proteolitic and anaerobic bacteria. These groups were selected because of their activity in fish spoilage and/or infection. The microbial groups were studied as follows: direct plate count for total number, most probable number (MPN) for coliforms and fecal type strains according with Mc Crady tables; proteolitic and anaerobic bacteria were cualitatively tested, cuantitative determinations are given in two tables. Obtained results show a heavy water pollution that rapidly decreases towards the harbour entrance.

Three experiments were designed to determine the parameters of virus infection, antibodies and mortality with three different MD isolates inoculated in one day old birds from commercial origin. The animals were divided in three inoculated lots (1-2-3) and three control groups (4-1, 4-2, 4-3) and were followed weekly from hatching through 17 weeks. The former were inoculated respectivelly with FOV-6, FCV-8 and FCV-9. Each day old bird received between 50-75 FPU/bird by I.P. route. Samples were taken from circulating blood of five birds by cardiac puncture with an heparinized syringe (20 U/ml), were centrifuged and the white cells inoculated to 5-15 four day old embryos by yolk salk route for virus detection; plasma was assayed by immunodiffusion against MD antigen in order to detect precipitating antibodies, and mortality was recorded after microscopical examination. Infection appeared to persist indefinitelly in the host chicken flock and coexist with (100%) precipiting antibodies, (Fig. 1-2-3). First virus isolation was accomplished after 4 weeks post-inoculation and the 100% porcentage of antibodies, was found only 1-3 weeks after the first peak of viraemia. With the most pathogenic isolate FCV-6 (ig. 1) the antibody response was significantly delayed. Maternal antibodies decreased more rapidly in inoculated than in control birds. Accumulative mortality showed isolate FCV-6 and FCV-8 as pathogenic strains and FCV-9 strain as less pathogenic. Mortality begun 1-3 weeks after the first peak of virus detection in the flock, independently of the pathogenic pattern of the isolate, but frecuencies of death were markedly different.

This article presents the results obtained in the search for the hepatitis B antigen by the counter-immunoelectrophoresis technique in sera of more than 50.000 persons from Córdoba, Argentina. Groups of voluntary blood donors, general population, 20 years old army recruits, patients, with acute hepatitis and patients admitted to a hospital due to other diseases were included in this study. In the apparenly healthy population the positivity of the test ranged between 0.33 to 0.53 percent; the highest rate was found among the recruits. In the group of patients with acute hepatitis, 38.53% of the sera were positive. No statistically significant differences were observed in the monthly distribution of the hepatitis B antigen during the period of study. These results are compared with those found by other workers in different countries. This study shows the importance of the early detection of the hepatitis B antigen in blood donors, to reduce the incidence of hepatitis transmitted by transfusions. The importance of establishing centers for the standardization and control of reagents, as well as for the training of laboratory personnel is emphasized.

Twelve strains of Nocardia isolated from sputa, bronchial washings and pleural fluids, were studied. The classification was based on the following characteristics: a) acid-fastness; 2) ability to disolve crystals of tyrosine and xantine; 3) hydrolysis of casein; 4) growth in dilute gelatin medium (0.4%) and 5) galactose acidification. Direct cultivation of the clinical material in Czapek liquid culture medium without carbon source and containing a paraffin rod (pariffin-bait technic), as well as the routin T.B. sputum digestion and concentration with NaOH solution followed by its cultivation in Loewenstein's medium, were employed for the isolation of Nocardia. The sensitivity of the strains to tuberculostatic drugs was investigated using the Canetti's method, as was the ability to growth in Sabouraud and lactrimel culture media supplemented with 100 mug/ml of rifamycin. Finally the pathogenicity test was carried out by intraperitoneal and intramuscular inoculation in guinea-pigs. All the strains were classified as Nocardia asteroides. Seven starins were isolated from patiens with lung conditions of no nocardial etiology. The diagnosis of nocardiosis of the lung was demonstrated in the remaining five patiens by microscopical observation of Nocardia in clinical specimens, by the repeated cultures obtained from these materials and, finally, by the fact that an improvement of the clinical symptomatology was obtained by sulfa administration.

This paper presents the results obtained with the sera of persons having direct or indirect contact with ethiological agents of leptospirosis. Exposure could have ocurred during the performance of their duties, by contact with contaminated habitats and/or animals. One thousand thirty eight sera from persons living in different regions of Argentina were received at the laboratory and studied by the microscopic agglutination tecnique. Of these, 164 were positive (15.7%) to serveral serotypes. One hundred thirty eight sera of the 857 males studied (16.1%) were positive, and 16 out of 173 female sera (15%) were positive. Males between 31 and 40 years of age had the highest proportion of positives (21.7%); however, among females the group between 21 and 30 years of age had the highest rate (14.2%). Most of the sera reacted to L. brastislava (15%), followed by L. icterohaemorrhagiae (17.7%) and L. butembo (14%), with nine other serotypes at lower rates.