National Center for Biotechnology Information NCBI NLM MEDLINE humans pubmed abstract nih national institutes of health national library of medicine logistic models risk factors drug resistance multiple bacterial* bacterial typing techniques hospital mortality intensive care units water microbiology disease outbreaks / prevention & control* cross infection / prevention & control cluster analysis pmid:12186209 doi:10.1086/502082 geir bukholm tone tannaes nils smith-erichsen cross infection / mortality* infection control / methods norway / epidemiology population surveillance / methods pseudomonas infections / mortality* pseudomonas infections / prevention & control