Antibiotic Usage and Microbial Resistance in an Intensive Care Nursery

Kanamycin sulfate was replaced by gentamicin sulfate in an effort to control an outbreak of nosocomial infections caused by enteric organisms with R-factor-mediated kanamycin resistance in an intensive care nursery. Within a month the kanamycin-resistant organisms were essentially eliminated from the nursery, indicating that the selective pressure provided by the extensive use of kanamycin was a major factor in causing and propagating the outbreak. Over a period of observation of 15 months, a significant increase in the gentamicin resistance of the Gram-negative intestinal flora of the infants occurred, but no clinical infections due to gentamicin-resistant enteric organisms were observed.