Investigation ofanOutbreak ofClostridium dijficile Infection in aGeneral Hospital byNumerical Analysis ofProtein Patterns bySodiumDodecyl Sulfate-Polyacrylamide GelElectrophoresis

gel electrophoresis ofwhole-cell proteins. Eachprotein pattern wascharacterized bythepresence ofonetothree dense bandswhichwerehighly reproducible. Thefirst 100strains (inchronological order) wereusedasthe basis foranumerical analysis whichdivided thestrains into17phenons (EPtypes 1to17). Theprotein patterns oftheremaining 45strains wereidentified totype bycomparing their individual patterns against a databasemadeupoftheprotein patterns ofthefirst 100strains. EPtype1wasthemostcommon, with70of 139(50%1) patient isolates having this pattern type, anditaccounted for26of35strains (74%) frompatients inamedical teaching wardfromwhichtheoutbreak wasbelieved tohaveoriginated. Thistype wasalsofound asahighproportion ofisolations inanumberofother medical andoncology wards, butthemajority ofthese isolates occurred subsequent totheisolations ontheinitial outbreak ward.Thistechnique cantherefore provide amethodfortracing thepossible spread ofepidemic strains inhospitals andother institutions and maycontribute toabetter understanding oftheepidemiology ofC.diJficile. Clostridium difficile hasbeenwidely implicated asthemajor causeofpseudomembranous colitis anddiarrhea associated withantimicrobial (AAD)and/or antineoplastic chemotherapy inadult hospitalized patients (2,18,23). Inthemostserious formofthedisease (pseudomembranous