BACKGROUND: We have experienced sporadic cases of nosocomial bacteremia/sepsis due to contaminated rubber caps of intravenous (IV) fluid bottles from May through August in 1996. We investigated the possible sources of the infections, and developed the measures to control this type of nosocomial infections. METHODS: During initial investigation of an outbreak of sporadic nosocomial bacteremia we could not found possible sources of infections from medical care providers. However, some rubber caps of IV fluid bottles showed water drops on top of them, and were suspected as possible sources of the infection. A total of 95 caps including 50 wet caps and 45 dry caps, were randomly selected from nursing stations and pharmacy receiving area for culture. We also investigated if routine disinfection methods were effective to sterilize the contaminated caps as follows; twenty of 50 wet caps were randomly selected and were divided into 2 groups. Caps of one group were disinfected with 70% isopropanol alcohol wipes and the other with 70% isopropanol alcohol wipes plus Betadine. All caps were subjected to culture before and after disinfections. Cultures were performed on blood agar plate after inoculating by using swab. RESULTS: The result of culture showed that 128 of 50(56%) wet caps were contaminated by Burkholderia picketti, Pseudomonas species, glucose-nonfermenting bacilli, Acinetobacter lowffii and Alkaligenes species. One of 45 (2.2%) dry caps grew Burkholderia picketti and Pseudomonas species. Both 70% isopropanol alcohol and 70% isopropanol alcohol plus povidone-iodine (Betadine) wipes terilized contaminated caps effectively when they were used for disinfecting caps. CONCLUSION: It is concluded that wet caps of IV fluid bottles are indicative of possible contamination by microorganisms. And use of alcohol wipe and/or Betadine to disinfect ontaminated caps at time preparing for infusion of IV fluids can be one of effective sterilization methods.