Changing pattern of the antimicrobial susceptibilities of Escherichia coli in neonatal infections

Five infants with E. coli meningitis failed to respond to kanamycin therapy. Review of kanamycin susceptibilities of E. coli isolated from blood cultures of neonates at Parkland Memorial Hospital revealed 6 per cent resistance from 1963 to 1968, and 27 per cent resistance during the past 3 years. The antimicrobial susceptibilities of 520 E. coli from 7 nurseries in North America were studied. A significant number of strains were resistant to kanamycin, streptomycin, and ampicillin: kanamycin, 14 to 34 per cent (mean 27 per cent); streptomycin, 20 to 50 per cent (mean 34 per cent); and ampicillin, 7 to 35 per cent (mean 23 per cent). In contrast, 0 to 8 per cent (mean 4 per cent) of E. coli were resistant to gentamicin and 0 to 13 per cent (mean 5 per cent) to polymyxin B.