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Biomedical subjects

S C Pal

Publications and source records attributed to S C Pal.

At least 73 records · Page 4Linked to original sources

Serotypes & biotypes of Campylobacter jejuni & C. coli from diverse sources in Calcutta.

C. jejuni and C. coli isolates from diverse sources in Calcutta were serotyped and biotyped according to the Lior scheme. Of the 55 strains examined, 85.5 per cent reacted with one or another of the 73 antisera available. This included the formation of two new serogroups, LIO 67 and LIO 76. C. coli serogroup LIO 46 biotype II was the most frequently encountered strains (14.5%), followed by C. coli serogroup LIO 29, 55 biotype II (10.5%) and C. jejuni serogroup LIO 54, biotype I (5.5%). Serogroups recovered from animals and birds were also found to be prevalent in strains isolated from clinical sources, confirming the zoonotic implications of the disease.

Animals↗

Efficacy & safety of glycine fortified oral rehydration solution in the treatment of acute dehydrating diarrhoea in children.

Efficacy and safety of glycine fortified oral rehydration solution (ORS) was compared with a standard ORS (WHO formula) in a randomized clinical trial in children aged between 4 months and 5 yr with moderate degree of dehydration owing to acute watery diarrhoea. No significant differences (P greater than 0.05) were observed in diarrhoeal stool output, duration of diarrhoea and intake of ORS between the study and control groups respectively. Thus glycine fortified ORS does not have any additional advantage over standard ORS. Moreover, two children developed hypernatraemia after receiving glycine fortified ORS in contrast to the control group. It is therefore suggested that glycine supplemented ORS should not be prescribed for the treatment of diarrhoeal dehydration in children.

Child, Preschool↗

A small nonconjugative plasmid encoded for streptomycin-resistant character in Shigella dysenteriae.

Conjugative transfers of drug-resistant plasmids in Shigella dysenteriae type 1 isolated from the epidemic in West Bengal were unsuccessful. The plasmids were non-transmissible in spite of having the fertility factor F, genetically labelled with kanamycin-resistant transposon Tn903 (pWS 7). A small 2.5 kb nonconjugative plasmid encoded for the streptomycin-resistant character. Cured plasmid-less strains of S. dysenteriae 1 showed resistance to sulfonamides.

Drug Resistance, Microbial↗

Toxin profiles of Vibrio cholerae non-O1 from environmental sources in Calcutta, India.

A collection of Vibrio cholerae non-O1 isolated from the aquatic environs of Calcutta, a cholera-hyperendemic area, were examined for the production of cholera toxin (CT), Shiga-like toxins (Vero toxins), heat-stable enterotoxin, and hemolysins. Two (0.5%) V. cholerae non-O1 isolates produced CT. The DNA from both these isolates also hybridized with a DNA probe containing sequences encoding the A subunit of CT. None of the strains produced Shiga-like toxins or heat-stable enterotoxin. Hemolytic activity was observed in 89.7% of the strains, of which 36.1% exhibited biological activity in the suckling mouse. However, none of them produced a hemolysin that cross-reacted with the thermostable direct hemolysin of Vibrio parahaemolyticus. It appears from this study that a small percentage of environmental V. cholerae non-O1 strains do possess the potential for causing cholera-like diarrhea.

Cholera↗

Observations on the interpretation of amoebic serology in endemic areas.

Antibody to Entamoeba histolytica antigen was evaluated in cases of proven and suspected intestinal amoebiasis as well as in extra-intestinal cases from an endemic area. Screening methods included the gel diffusion precipitation test (GD), counter immunoelectrophoresis (CIE) and the indirect haemagglutination test (IHA). Control populations consisting of asymptomatic cyst passers, non-amoebic individuals, patients with giardiasis and cases of enteric fever were also screened using the above tests. All (100%) cases of amoebic liver abscess and 75-80% of hepatic amoebiasis without overt abscess formation could be detected by serology, with good correlation between the tests used. However, the interpretation of serology in cases of proven and suspected intestinal amoebiasis posed two main problems. The presence of low antibody levels even in proven cases and the persistence of antibodies due to past infection was found to reduce the diagnostic efficiency of serology for acute intestinal amoebiasis. There was no statistical difference between intestinal cases and controls when comparing either percentage of cases detected or titre of antibody obtained. The results of this study indicate that serology for acute intestinal amoebiasis can be unreliable; however, it is of undoubted value as an adjunct to clinical diagnosis in cases of hepatic amoebiasis.

Animals↗

Hemolytic activity of and lethal toxin production by environmental strains of Vibrio parahaemolyticus.

Repeated subculturing of Kanagawa-negative strains of Vibrio parahaemolyticus on Wagatsuma agar induced the production of a hemolysin which was not the thermostable direct hemolysin. Crude hemolysin exhibited a 30 to 40% lethal toxicity in mice after intraperitoneal injection. A 21-kilodalton protein band was observed with all the environmental isolates in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Results suggested that a certain percentage of environmental strains of V. parahaemolyticus is responsible for pathogenesis.

Animals↗

Evaluation of the multitest medium for rapid presumptive identification of Vibrio cholerae from environmental sources.

The multitest V. cholerae medium (VC medium) for rapid presumptive identification of Vibrio cholerae was evaluated. On the basis of reactions in the VC medium, 379 strains recovered during a yearlong ecological study in Calcutta were presumptively identified as V. cholerae. Further phenotypic characterization of these strains revealed that the reactions of 371 (97.9%) isolates were consistent with that of V. cholerae. False-positive reactions were exhibited by eight (2.1%) strains, three of which were identified as Vibrio fluvialis biotype 1. By slightly varying the basic formulation of the VC medium, we could eliminate some false-positive reactions. On the basis of the present evaluation, we recommend the routine use of the VC medium.

Culture Media↗

Comparison of selective media for primary isolation of Aeromonas species from human and animal feces.

Five selective media were evaluated for their effectiveness in the primary isolation of Aeromonas spp. from human patients with acute diarrhea and from healthy domestic animals. Sheep blood agar with 30 mg of ampicillin per liter (ASBA30) yielded a significantly higher percentage of positive specimens as compared with the four other media. The effective combination of two selective media with which 98% of all isolates were detected and with which all of the three human-associated Aeromonas spp. could be isolated was ASBA30-DNase-toluidine blue agar. ASBA30 was the most sensitive medium since it permitted more growth of Aeromonas colonies and effectively suppressed competing microflora. We recommend the use of ASBA30-DNase-toluidine blue agar for investigations in which an attempt is made to assess the significance of Aeromonas spp. in the etiology of human diarrhea.

Acute Disease↗

Observation on a 65-kilodalton protein isolated from kanagawa positive strains of Vibrio parahaemolyticus.

Crude hemolysin from four KP+ strains of Vibrio parahaemolyticus belonging to serotype 02:K3 exhibited a major protein band (molecular weight, 65 kilodaltons (kDa] in addition to a previously known thermostable direct hemolysin band (molecular weight, 21 kDa) in SDS - polyacrylamide slab gel electrophoresis. These strains showed maximum virulence leading to 100% mouse lethality within 2-6 h. It is hypothesized that this 65-kDa protein may play a vital role in the pathogenesis of the disease caused by V. parahaemolyticus.

Bacterial Proteins↗