standard zones of clearing for various antibiotics
DESCRIPTION
journalTRANSCRIPT
Zones of clearing for various antibiotics
Antibiotic (and disc identifier)
Inhibition zone diameter (mm)
Resistant Intermediate Susceptible
Bacitracin (B) 8 or less 9 - 12 13 or more
Optochin Less than 14 14 and more
Novobiocin (NV) 16 or less More than 16
SPECIFIC RESULTS FOR OPTOCHIN
Inhibition zone (mm) Result
>= 14 Streptococcus pneumoniae
0 Viridans streptococci other than S. pneumoniae
< 14 S. pneumoniae is to be confirmed by the bile-solubility test