The original source paper for the work quoted by Tom Sanford is:
 
Alippi, A (1994) Sensibilidad "in vitro" de Bacillus larvae frente a
diferentes antimicrobianos.  Vida Apicola 66:20-24.
 
English summary is as follows:
 
"Five strains of Bacillus larvae isolated from infected brood combs of
different geographical origin were tested for their sensitivity to 22
antibiotics by the agar diffusion disk method.
 
All B. larvae cultures were susceptible to ampicillin (10ug), ampicillin
(10ug) + sulbactam (10ug), cefaclor (30ug), cephalotin (30ug),
clindamycin (2ug), erythromycin (15ug), nitrofurantoin (300ug),
norfloxacin (10ug), penicillin G (10ug), pefloxacin (5ug), rifampin (5ug),
tylosin (30ug) and vancomycin (30ug), and resistant to nalidixic acid
(30ug), pipemidic acid (20ug), chloramphenicol (30ug), polymyxin B
(30ug), sodium sulphathiazole (300ug) and thrimethoprim (1.25ug) +
sulfametoxazol (23.75ug).
 
As regard to streptomycin (10ug) and oxacillin (1ug), the strains showed
different sensitivity patterns.
 
In antimicrobial disk susceptibility tests for oxytetracycline (30ug), four
strains were resistant and one was moderately susceptible.  The minimal
inhibitory concentrations (MIC) of OTC for five strains of Bacillus larvae
were 1ug/ml (1 strain), 2ug/ml (3 strains), and 4ug/ml (1 strain)."
 
ug=microgram