A Study on the Validity of the Hospital Infection Surveillance Records Collected by Ward Liaison Nurses

Cho, Yoon Sook; Kim, Joung Soon

Abstract

BACKGROUND
Hospital infection surveillance is a dynamic process for gathering, managing, analyzing, reporting and re-evaluating the data. Recently there has been an increased awareness of the importance of hospital infection surveillance and management program in Korea. The most ideal way among the hospital infection surveillance systems is known to be the "reference method". In this method all hospital patient records and charts are reviewed and the infected patient are investigated in daily basis. However it requires enormous efforts to apply this method in hospitals with limited personnel resources. Although the number of the hospital having full-time hospital infection control nurses has been increased considerably in Korea the effective hospital control programs have not been established yet in most hospitals owing to the lack of full-time hospital infection control nurses. Nevertheless it became indispensable to develop an alternative hospital infection surveillance program that is readily available. This study was carried out to investigate epidemiologic characteristics, and assess the efficiency and validity of ward liaison surveillance method for nosocomial infection surveillance in a general hospital without full-time infection control nurses. METHOD: During the period of the study, from March 1 to March 31, 2000, cases of hospital infection collected by two different methods, reference method and ward liaison nurse surveillance, were compared. The validity of ward liaison surveillance data was examined using the data collected by the reference method as gold standard. RESULT: In the data collected by the reference method, 94 cases of hospital infection were identified whereas 83 cases by the ward liaison nurses. The incidence rate of hospital infection was 9.5% during one month; the incidence rates were higher in males (12.6%) than female (6.7%) and in age group of 50s. The incidence rates by ward were 38.8% in intensive care unit, 45.5% in neurosurgery, 18.6% in neurology ward, 12.8% in internal medicine, 10.6% in orthopedic ward, and 8.6% in general surgery. Sites of hospital infection in the order of decreasing frequency were urinary tract (24.8/1000 discharge patients), lung (22.2), wound (18.2), and other respiratory systems (15.2). The type of microorganisms isolated were 16: three gram-positive bacteria, eleven gram-negatives and two fungi. Staphylococcus was the most frequently isolated organism, 21 strains, among which 17 strains were methicillin-resistant Staphylococcus aureus (only one strain was sensitive to methicillin) and three strains were methicillin resistant Staphylococcus epidermidis. Seventeen strains of Pseudomonas aeruginosa were isolated from pneumonia, urinary tract, and wound. Escherichia. coli, Serratia marcencecs, Acinetobacter baumannii, Klebsiella pneumoniae, Enterococcus faecalis, E. faecium, Enterobacter cloacae, Streptococcus pneumoniae, and Candida albicans were also isolated. There were twenty-two specimens that revealed no growth of any organisms. In the ward liaison nurse surveillance method, the number of false positive hospital infection was eleven cases and the false negative was 22 cases. The validity evaluated by four different measurements were sensitivity 76,7%, specificity 98.7%, positive predicted value 86.7%, negative predicted value 97.5%. Thus the ward liaison nurse surveillance method was shown to be a valid method with high efficiency. The false positive and false negative cases were mainly occurred by the deficient knowledge in the definition of hospital infection, and deficient skills of investigating the patient's symptoms and clinical course; the liaison nurses had not checked all the surgical site resulting in low sensitivity in surgical site infection.
CONCLUSION
According to the results, the epidemiologic characteristic of hospital infection in this particular community hospital studied was not much different from other study results; the incidence rate of hospital infection for one month was 9.5%. On the other hand the ward liaison nurse surveillance method was shown to be satisfactory in detecting hospital infection. This could be a useful method for hospitals without full-time infection control nurses. Furthermore, the validity of this method could be improved by accumulation of the knowledge and skills on hospital infection surveillance through a well planned on-the-job training program for the nurses.