In 2007, Vincent and colleagues conducted a prospective, multicenter, international study on the prevalence of infection in ICUs in which a total of 1,265 ICUs in 75 countries took part. Of the 13,796 patients included in the study, 51% had an infection. Of those infections, 64% were in the lungs, 20% in the abdomen, 15% in the bloodstream, and 14% in the renal tract/genitourinary system. Infection was directly related to disease severity and degree of organ failure as well as to length of ICU stay and death. Of patients in the ICU for one day or less, 32% had an infection compared with 70% of patients in the ICU for more than seven days.

A high percentage (70%) of infections were positive for microbial isolates; Staphylococcus aureus was the most common gram-positive isolate, while Pseudomonas species were the most common gram-negative isolates. The type of organisms isolated varied by region, with rates of Acinetobacter infection varying most widely, from 3.7% in North America to 19.2% in Asia. Infection rates were related to how much a nation spent on health care, with lower infection rates seen in countries that spent a higher percentage of their gross domestic product on health.

The authors point out that regional differences in rates of bacterial infection may be because some local prevention control measures are more effective than others. In addition, they concluded that infection is common among ICU patients and that local-level infection data should be taken into account when administering prophylaxis and managing infection rates.