Methodologies used in surveillance of surgical wound infections and bacteremia in Australian hospitals.

BACKGROUND: The prevalence of nosocomial infection in Australian hospitals is estimated to be between 5.5% and 6.3%. Since 1989, infection control professionals (ICPs) in hospitals accredited by the Australian Council on Health Care Standards (ACHS) have been encouraged to collect nosocomial infection data according to ACHS methodology.

METHOD: In 1996, we surveyed members of the Australian Infection Control Association to examine the time spent on surveillance, the practice of surveillance of all hospital infections (hospital-wide surveillance), case-finding methods, case definitions, and reporting routinely used by ICPs in acute care hospitals. We also examined the ICPs' education and experience in infection control (IC).

RESULTS: The survey was completed and returned by 65% (644 of 993) of Australian Infection Control Association members. Of the ICPs who completed the survey, 47.8% (308 of 644; 95% CI, 43.9%-51.7%) met the criteria for inclusion, because they coordinated an IC program in an acute care or surgical hospital and performed surveillance for either surgical wound infection, intravascular device-related bacteremia, or non-device-related bacteremia. Of the ICPs who reported their facility's accreditation status, 93.5% participated in ACHS system. Most (97.6%) ICPs had completed hospital-based general registered nurse training. Only 1.9% (6 of 308) of ICPs reported completion of continuing education relating to hospital epidemiology. The number of years of IC experience ranged from zero to 35 years, with a median of 4 years. ICPs spent a substantial proportion of their total weekly IC time on surveillance irrespective of ACHS accreditation; 19.5 hours in ACHS hospitals and 15.6 hours in non-ACHS hospitals (P =.33). More than three quarters (76.0%) of ICPs performed hospital-wide surveillance. The case-finding methods, definitions of infections, and reporting formats varied greatly. The definition most commonly applied by ICPs (6.8%; 95% CI, 4.1%-10.4%) to define surgical wound infection was infection within 30 days after the operative procedure, plus purulent drainage, plus isolation of organisms from a culture from the incision site, plus diagnosis by a medical officer. A 5-item definition of a patient being asymptomatic, plus afebrile on admission, plus infection occurring at least 48 hours after admission, plus the patient having a fever of >38 degrees C, plus a recognized culture from one or more bottles was used by 15.7% (95% CI, 11.3%-21.0%) of ICPs to define a case of bacteremia.

CONCLUSION: Surveillance is the core business of Australian ICPs and consumes a substantial proportion of their time. The importance of surveillance, the epidemiologic limitations of the current ACHS system, and the nonstandard methods we report indicate that improved methodology is required for case finding and reporting of nosocomial infections. Australian ICPs should complete training in the principles of surveillance and epidemiology. With this training, ICPs can work collaboratively with other health care professionals to develop epidemiologically sound, local, nosocomial surveillance systems and lobby for a voluntary, national, standardized, risk-adjusted system of targeted nosocomial surveillance.