Microbiologic surveillance data, such as those provided by the National Nosocomial Infections Surveillance System, supply information on current nosocomial pathogens in the United States. Many species show resistance to commonly used antimicrobials and, in many cases, it is emerging resistance. A novel form of resistance in Kelbesiella pneumoniae and E. coli is caused by extended-spectrum cephalosporinases. Thirty percent of Haemophilus influenzae isolates are resistant to ampicillin because of beta-lactamase production. To minimize the development of resistance, antimicrobials must be administered judiciously, and infection-control practices must be instituted and followed.
Bacterial resistance remains a major concern.
Recently, genetic transfers from saprophytic, non-pathogenic, species to pathogenic S. pneumoniae and N. Meningitidis have introduced multiple changes in the penicillin target molecules, leading to rapidly growing penicillin resistance. Resistance emerges in the hospital environment but also, and increasingly, in the community bacteria. Widespread resistance is probably associated with antibiotic use, abuse, and misuse but direct causality links are difficult to establish. In some countries as in some hospitals, unusual resistance profiles seem to correspond to unusual antibiotic practices. For meeting the resistance challenge, no simple solutions are available, but combined efforts may help.