[1] GEORGETOWN UNIV,SCH MED,WASHINGTON,DC 20057
[2] CHILDRENS HOSP,NATL MED CTR,CLIN MICROBIOL LAB,WASHINGTON,DC 20010
[3] GEORGE WASHINGTON UNIV,SCH MED,WASHINGTON,DC 20006
[4] CHILDRENS HOSP,NATL MED CTR,DEPT INFECT DIS,WASHINGTON,DC 20010
[5] VET ADM MED CTR,GI HEPATOL SECT,WASHINGTON,DC 20422