Research Article

Identification of Streptococcus pneumoniae: Development of a Standardized Protocol for Optochin Susceptibility Testing Using Total Lab Automation

Table 3

DOIZ (diameters of inhibition zones) stratified by agar, imaging time point, and outcome (≥14 mm; <14 mm); COS_BD: Columbia agar 5% sheep blood (Becton Dickinson), COS_bmx: Columbia agar 5% sheep blood (bioMerieux), MHB_bmx: Müller-Hinton agar with 5% sheep blood (bioMerieux), MHF_bmx: Müller-Hinton agar fastidious with 5% horse blood (bioMerieux), MHF_Ox: Müller-Hinton agar fastidious with 5% horse blood (Oxoid), TSA_bmx: Tryptic Soy agar with 5% sheep blood (bioMerieux), and TSA_Ox: Tryptic Soy agar with 5% sheep blood; bold italic font: DOIZ < 14 mm (12 h); ng: no growth.

AgarDOIZ imaging time pointDOIZDOIZngTotal
<14 mm≥14 mm

COS_BD7 h141840198
12 h91890198
18 h311670198
24 h531450198

COS_BD total1076850792

COS_bmx7 h11970198
12 h01970198
18 h21950198
24 h41940198

COS_bmx total97830792

MHB_bmx7 h21924198
12 h11970198
18 h21960198
24 h121860198

MHB_bmx total177714792

MHF_bmx7 h31932198
12 h41940198
18 h251730198
24 h421560198

MHF_bmx total747162792

MHF_Ox7 h81864198
12 h111870198
18 h421560198
24 h771210198

MHF_Ox total1386504792

TSA_bmx7 h51912198
12 h01980198
18 h11970198
24 h51930198

TSA_bmx total117792792

TSA_Ox7 h11934198
12 h01980198
18 h01980198
24 h31950198

TSA_Ox total47844792

Total3605168165544