METHODS	Between November 1994 and March 1995 , 1108 asymptomatic male US Marine Corps trainees , located in Southern California , were randomly assigned to one of three intervention groups : ( 1 ) weekly oral azithromycin , 500 mg ( n = 362 ) ; ( 2 ) 1.2 MU benzathine penicillin G , intramuscularly once ( n = 374 ) ; or ( 3 ) no chemoprophylaxis ( n = 372 ) .\