Search PubMed⌕ Search

Biomedical subjects

N Datta

Publications and source records attributed to N Datta.

126 records · Page 7Linked to original sources
PubMed1966

The purification and properties of a penicillinase whose synthesis is mediated by an R-factor in Escherichia coli.

1. The penicillinase (beta-lactamase) from Escherichia coli strain TEM has been purified and its activity against a range of penicillin and cephalosporin derivatives measured. 2. The enzyme shows little resemblance to penicillinases from Bacillus cereus, Bacillus licheniformis and Staphylococcus aureus. 3. The molecular weight of the enzyme is 16700+/-5%, which is about half the value obtained for other penicillinases. 4. The enzyme is most similar in properties to a crude preparation of a penicillinase from Klebsiella (Aerobacter) aerogenes, but clearly different from crude enzyme preparations from other strains of E. coli. 5. Since penicillinase synthesis in E. coli strain TEM is mediated by an R-factor known to infect many other species of Enterobacteriaceae, the appearance of similar enzymes in other Gramnegative species is not surprising.

Cephalosporins↗
PubMedDate not supplied

Impact of annual immunisation programme with oral polio vaccine on the prevalence of paralytic poliomyelitis.

Lameness survey was conducted in a rural community development block of Haryana in 1985. Enumerators contacted school teachers, anganwadi workers and several key informants in the community to identify lame children in 1-11 years age-group. Physician verified 219 lame cases to be due to poliomyelitis. Prevalence of poliomyelitis lameness was 7.3/1000 children born in 1974-76, 7.7/1000 children born in 1977-1980 and 2.3/1000 children born in 1981-1984 (expected to increase to 3.1/1000 when all children born in 1981-84 cross 5th year of life). Immunisation coverage with 3 doses of oral polio vaccine (OPV) was less than 10% during 1974-80 when immunisation was a clinic based activity. Coverage increased from 50 to 80% during 1981-85 when OPV was given in annual immunisation campaign. The results indicate that prevalence of paralytic poliomyelitis dropped at least by 60% after giving OPV in annual immunisation campaigns.

Child↗
PubMedDate not supplied

Plasmids of the same Inc groups in Enterobacteria before and after the medical use of antibiotics.

Conjugative plasmids were common in enterobacteria isolated before the medical use of antibiotics. Plasmid F of Escherichia coli K-12 was one example and we identified others in over 20% of a collection of strains isolated between 1917 and 1954, the Murray collection. In the past 25 years, conjugative plasmids encoding antibiotic resistances have become common in bacteria of the same genera as those of the Murray Collection--Salmonella, Shigella, Klebsiella, Proteus, Escherichia. The present study was made to show whether the 'pre-antibiotic' plasmids belonged to the same groups, as defined by incompatibility tests (Inc groups), as modern R plasmids. Of 84 such plasmids established in E. coli K-12, none with antibiotic resistance determinants, 65 belonged to the same groups as present resistance (R) plasmids. Thus the remarkable way in which medically important bacteria have acquired antibiotic resistance in the past 25 years seems to have been by the insertion of new genes into existing plasmids rather than by the spread of previously rare plasmids.

Anti-Bacterial Agents↗