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A total of 8579 Salmonella strains received during 1973-1982 were tested for their antibiogram patterns against nine routinely used antibiotics including gentamicin. Of these, 380 strains (4.4%) showed resistance to gentamicin at levels of 10 micrograms/ml and above. A high degree of resistance to gentamicin was recorded in 1979 (18.7%) and 1980 (9.4%). M.I.C. levels of strains received during 1982 were determined and it was found that some strains had levels as high as 160 micrograms/ml. The comparative results of gentamicin resistance from 1973 to 1982 are presented and the public health significance of the alarming increase in two years (1979-1980) is discussed.

Seventy enterotoxigenic Esch. coli strains (18LT+; 46ST+ and 6LT+ST †) isolated from infants and children with acute diarrhea were studied for the prevalence of R factor and also for enterotoxin (Ent†) plasmid transfer. These strains were received at the National Salmonella and Escherichia Centre, Central Research Institute, Kasauli during 1981. Sixty one strains were found to be resistant to two or more drugs and 9 were sensitive to all the drugs. Of the total, 24 (34·2%) strains showed the presence of conjugative plasmid; of these 10 (41%) strains showed transfer of Ent† plasmid, of the 24 strains 6 strains were positive for LT and 18 for ST. Of the 6 LT† strains which showed presence of R factor, Ent+ plasmid could be demonstrated in four strains and out of 18 ST† strains Ent† plasmid could be transferred in six Esch. coli strains.

A phage-typing system of Salmonella bareilly based on lysogeny is presented. In the present study which comprised 378 strains, fifteen different phage types named 'a' through 'o' were established. With this system 70.3% of the strains could be typed by using five indicator strains.

A total of 348 Esch.coli strains isolated from cases of diarrhoea in infants and children during 1979 and received at the National Salmonella and Escherichia Centre, Central Research Institute, Kasauli were serotyped and tested for the prevalence of multiple drug resistance. These strains belonged to 43 different serotypes, the most common being 060, 01, 011, 017 and 020. About one third (113) of the strains could not be typed. It was found that 248 strains (80.5%) were resistant to 3 or more drugs. The resistance pattern of various serotvpes and their epidemiohgical significance with particular reference to diarrhea in children isdiscussedln this report.

Atotal of 315 strains of Escherichia coli causing diarrhea in infants and children received at the National Salmonella and Escherichia Centre, Central Research Institute, Kasauli, during the year 1981 were studied for serotype and enterotoxigenicity. One hundred and eighty eight strains belonged to infantile diarrhea cases and the predominant serotype isolated was 05, followed by 017, 01, 025, 035 and so on. One hundred and twenty seven strains belonged to childhood diarrhea cases and here the most common serotype was 025, followed by 017, 02, 060, 057 and so on. Seventy strain (22.21%) were enterotoxigenic, of these 18 strains (5.71%) produced LT, 46 strains (14.60%) produced ST and only 6 strains (1.90%) produced both LT and ST.