[1] ST VINCENTS MED CTR, PORTLAND, OR USA
[2] ST FRANCIS REG MED CTR, WICHITA, KS 67214 USA
[3] LOUISIANA STATE UNIV, MED CTR, NEW ORLEANS, LA 70112 USA
[4] VET ADM MED CTR BRENTWOOD, LOS ANGELES, CA 90073 USA
[5] INDIANA UNIV, MED CTR, INDIANAPOLIS, IN 46204 USA
[6] CLEVELAND CLIN EDUC FDN, CLEVELAND, OH 44106 USA
[7] CTR DIS CONTROL, ATLANTA, GA 30333 USA
[8] HOP ST JOSEPH, F-75674 PARIS 14, FRANCE
[9] ST LUC HOSP, MONTREAL, QUEBEC, CANADA
[10] INST MED MICROBIOL, WEINGARTEN, GERMANY
[11] UNIV TUBINGEN, W-7400 TUBINGEN 1, GERMANY
[12] UNIV LONDON LONDON HOSP, COLL MED, LONDON E1 1BB, ENGLAND
[13] UNIV ZURICH, CH-8006 ZURICH, SWITZERLAND