Biomedical subjects
Publications and source records attributed to N Năcescu.
A 47-year-old male suffering from chronic purulent ear discharge was investigated bacteriologically in autumn 1977. The isolated strain was identified as Vibrio alginolyticus. The fact that the patient spent his vacation at a Black-Sea resort every year strongly pleads for a direct inoculation of the halophilic Vibrio.
390 food samples (frozen, Kippered herring, Salted roe, fresh carp and salted ham) were investigated for the presence of Vibrio parahaemolyticus. 8 V. parahaemolyticus strains were isolated from herring (6.2%) and roe samples (1.3%). Some biochemical characteristics are discussed. In food borne outbreaks, presence of V. parahaemolyticus must be investigated, especially when the epidemiologically incriminated food is fish or fish products.
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Out of 399 human faeces examined during the first eight months (1975) for the presence of NCV vibrios, one vibrio parahaemolyticus strains has been isolated from a man with acute gastro-enteritis (gastric and abdominal pains, nausea, diarrhoea, headache, general weakness), after having a meal with salted caviar. The strain belongs to Heiberg's group VII and Sakazaki's subgroup I. The virulence tested on chick embryo is 3 times higher (LD50 = 14 germs) if compared with the virulence of V. parahaemolyticus control strain (Sakazaki's strains). First isolation in Romania from a human stool (patient with acute gastro-enteritis).
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In August-October 1973 several NAG vibrio strains were isolated for the first time in our country from clinical cases of acute intestinal disturbances. The patients were admitted to hospital being clinically suspect of dysenteric syndrome or alimentary toxiinfection (nausea, vomiting, abdominal colics, tenesms, mucosanguinolent stools, aqeous stools from 4-5 up to 20 in 24 hours, with signs of dehydration). NAG vibrios were isolated from all the cultures in, practically, pure cultures. Epidemiologic survey in the village of B resulted in isolation of the same NAG vibrio strains from the samples collected from the direct contacts and drinking water sources. Therefore, NAG vibrios can unquestionably cause a diarrheic disease and it will be necessary to extend the bacteriologic diangosis also in this direction in all cases of diarrhea of "unknown etiology".
Considering the possible correlation between hemolytic and enterotoxigenic properties of Aeromonas strains mentioned in the literature, in the present work we studied the practical value of the hemolysis tests in the diagnosis of Aeromonas strains by using comparatively the hemolysis tube tests (with goat and sheep erythrocytes suspensions) as well as the technique on blood agar in aerobic conditions. There were studied comparatively 230 Aeromonas strains (different species: A. hydrophila, A. sobriae, A. caviae, A. veronii, A. salmonicida) isolated from different sources (meat products, fish of fresh waters, mussels, sea water, pipe water, diarrhoeal disease and animal faeces). The comparison among the used tests for proving the hemolytic activity of Aeromonas strains showed that: 61.89% and 56.51% from the total number of Aeromonas strains were hemolytic in the tube tests with 1% goat and 1% sheep erythrocytes suspensions respectively after 48 hrs followed by 51.72% and 48.25% strains by the 5% goat and 5% sheep blood agar plates respectively in anaerobiosis and after 48 hrs incubation at 37 degrees C. The highest incidence of hemolysin presence was pointed out in motile Aeromonas strains (A. hydrophila--60.11% and A. sobria--56.52%). Our results showing a high frequency of hemolytic activity among Aeromonas strains isolated especially in meat products are suggesting a possible correlation between the pathogenic potential and the hemolytic activity and are pleading for introduction of this test in the diagnosis of Aeromonas species.
The antigenic relationships between Vibrio cholerae and the oxidase-positive intestinal bacteria, agglutinated on slides by cholera antiserum, were investigated by the agglutination reaction. Of the 478 oxidase-positive strains studied only strain 209 A, belonging to species Aeromonas hydrophila was selected. Evidence was found of common agglutinogenic fractions between Vibrio cholerae and Aeromonas hydrophila 209 A. Attention is drawn to possible confusions in the preliminary stages of a laboratory diagnosis of cholera.
The purpose of this work was to select an available medium for Aeromonads isolation as well as to point out the Aeromonads presence in different foodstuffs of animal origin. Out of 15 tested media for Aeromonas isolation, two media, were selected: DFS as control medium and AGOS medium, both giving superposable results. 404 samples of foodstuffs of animal origin were examined; Aeromonads testing was performed qualitatively and quantitatively. 142 samples with a positivity percent of 51.40% were qualitatively tested. 262 samples with a positivity percent of 48.85% were quantitatively tested.
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1606 bacterial strains, belonging to Vibrio genus (189 V. cholerae 0 : 1; 1091 V. cholerae nongroup 0 : 1 and 205 V. halophilic strains) of different sources of isolation, were studied, concerning their hemagglutinating behaviour to 5 different animal red blood cells (human, bovine, chicken, African green monkey and guinea pig) in mannose/fucose presence/absence. The study aimed to establish the spectrum of their hemagglutinating activity as well as any possible correlation between the source of isolation, serogroup etc and the HA-type/subtype. Mannose/fucose sensitive as well as mannose/fucose resistant hemagglutinins were exhibited by the different tested strains. As unknown behaviour, a noticeable hemagglutination only in the carbohydrate presence was recorded. The HA-types and subtypes in 861 V. cholerae nongroup 0 : 1 tested strains are presented.
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