In a representative sample of US general hospitals, the authors found that the establishment of intensive infection surveillance and control programs was strongly associated with reductions in rates of nosocomial urinary tract infection, surgical wound infection, pneumonia, and bacteremia between 1970 and 1975-1976, after controlling for other characteristics of the hospitals and their patients. Essential components of effective programs included conducting organized surveillance and control activities and having a trained, effectual infection control physician, an infection control nurse per 250 beds, and a system for reporting infection rates to practicing surgeons. Programs with these components reduced their hospitals' infection rates by 32%. Since relatively few hospitals had very effective programs, however, only 6% of the nation's approximately 2 million nosocomial infections were being prevented in the mid-1970s, leaving another 26% to be prevented by universal adoption of these programs. Among hospitals without effective programs, the overall infection rate increased by 18% from 1970 to 1976.

No abstract

From a random sample of patients and hospitals and extrapolation ratios derived from the best available sources of data, the authors estimate that the nationwide nosocomial infection rate among the 6,449 acute-care US hospitals in 1975-1976 was 5.7 nosocomial infections per 100 admissions and that over 2 million nosocomial infections occurred in a 12-month period in these hospitals. Nosocomial urinary tract infections constituted 42% of the infections, surgical wound infections 24%, nosocomial pneumonia 10%, nosocomial bacteremia 5%, and nosocomial infections at all other sites 19%. If adjustments are made for the accuracy of the diagnostic method, the increasing nationwide secular trend, and the number of nosocomial infections in nursing homes, however, as many as 4 million nosocomial infections per year may now be occurring. This greatly exceeds previous estimates and calls for timely and accurate vital statistics on the problem.

Associational resistance, which refers to decreased herbivory experienced by a plant growing with heterospecific neighbors, is a well documented ecological phenomenon. In contrast, studies that describe increased herbivory due to heterospecific neighbors (associational susceptibility) are relatively rare. In this study we document associational susceptibility among hosts of the fall cankerworm (Alsophila pometaria). Cottonwoods (Populus angustifolia × P. fremontii) located under box elder (Acer negundo) were colonized by two to three times more cankerworms, and suffered two to three times greater defoliation than cottonwoods growing under mature cottonwoods, or cottonwoods growing in the open. This associational pattern reflects fall cankerworm's strong preference for box elder over cottonwood: egg densities were 26 times greater on box elder than cottonwood, first instar larvae consumed 75 times more box elder than cottonwood in larval palatability trials, and fourth instar larvae consumed three times more box elder than cottonwood. In terms of larval performance, first instar larvae exhibited approximately six times greater mortality and 40% slower development time on cottonwood relative to box elder, whereas fourth instar larval performance did not differ between the hosts. Based on these and other findings, we predict that, when generalist herbivores reach outbreak proportions and consume their preferred hosts, they will then move to nearby less‐preferred hosts to complete their life cycle. This “spillover” effect will result in associational susceptibility for less‐preferred hosts and is likely common in forest outbreak situations where herbivore densities are high. With increased emphasis on diversified plantings in agriculture and forestry, it is important to understand potential drawbacks such as associational susceptibility.

No abstract