Drug susceptibility testing of Nocardia spp. using the disk diffusion method

Prudhomme, Clémence; Joannard, Brune; Lina, Gérard; De Launay, Eleonore; Dumitrescu, Oana; Hodille, Elisabeth

doi:10.1186/s12941-024-00768-2

Annals of Clinical Microbiology and Antimicrobials

Table 2 Critical inhibition diameter determination for antibiotics and FDA criteria associated

From: Drug susceptibility testing of Nocardia spp. using the disk diffusion method

Antibiotic/Incubation time	Number of strains categorized S by the reference method	Number of strains categorized R by the reference method	Break point determination Method	Critical inhibition diameter value (mm; ≤ X: I/R; > X: S)	CA % 95%CI [; ]	vmj rate % 95%CI [; ]	maj rate % 95%CI [; ]
Imipenem/48 h	54	12	Youden index	28	93.1 [84.5; 97.7]	16.7 [2.1; 48.4]	3.7 [0.5; 12.7]
Imipenem/48 h	54	12	ROC01	28	93.1 [84.5; 97.7]	16.7 [2.1; 48.4]	3.7 [0.5; 12.7]
Imipenem/72 h (without N. farcinica. N. cyriacigeorgica)	45	26	Youden index	29	98.6 [92.5; 99.9]	0.0 [0.0; 13.2]	0.0 [0.0; 7.9]
	45	26	ROC01	29	98.6 [92.5; 99.9]	0.0 [0.0; 13.2]	0.0 [0.0; 7.9]
Amoxicillin-clavulanate/48 h	57	30	Youden index	20	89.3 [82.0; 94.3]	3.3 [0.1; 17.2]	15.8 [7.5; 27.9]
Amoxicillin-clavulanate/48 h	57	30	ROC01	20	89.3 [82.0; 94.3]	3.3 [0.1; 17.2]	15.8 [7.5; 27.9]
Amikacin/48 h	111	1	Youden index	22	97.3 [92.4. 99.4]	0.0 [0.0; 97.5]	1.8 [0.2; 6.4]
Amikacin/48 h	111	1	ROC01	22	97.3 [92.4. 99.4]	0.0 [0.0; 97.5]	1.8 [0.2; 6.4]
Amikacin/72 h	130	4	Youden index	25	98.5 [94.7; 99.8]	0.0 [0.0; 60.2]	1.5 [0.2; 5.4]
Amikacin/72 h	130	4	ROC01	25	98.5 [94.7; 99.8]	0.0 [0.0; 60.2]	1.5 [0.2; 5.4]
Tobramycin/48 h	62	50	Youden index	19	95.5 [89.9; 98.5]	0.0 [0.0; 7.1]	8.1 [2.7; 17.8]
Tobramycin/48 h	62	50	ROC01	18	95.5 [89.9; 98.5]	0.0 [0.0; 7.1]	6.5 [17.9; 15.7]
Tobramycin/72 h	69	65	Youden index	19	98.5 [94.7; 99.8]	0.0 [0.0; 5.5]	2.9 [0.4; 10.1]
Tobramycin/72 h	69	65	ROC01	19	98.5 [94.7; 99.8]	0.0 [0.0; 5.5]	2.9 [0.4; 10.1]
Ciprofloxacin/48 h	15	67	Youden index	24	85.6 [76.9; 91.9]	9.0 [3.4; 18.5]	6.7 [0.2. 31.9]
Ciprofloxacin/48 h	15	67	ROC01	24	85.6 [76.9; 91.9]	9.0 [3.4; 18.5]	6.7 [0.2. 31.9]
Ciprofloxacin/72 h	21	97	Youden index	25	79.9 [72.1; 86.3]	12.4 [6.6; 20.6]	0.0 [0.0; 16.1]
Ciprofloxacin/72 h	21	97	ROC01	27	82.8 [75.4; 88.8]	8.2 [3.6; 15.6]	4.8 [0.1; 23.8]
Moxifloxacin/48 h	32	35	Youden index	29	84.9 [76.0; 91.5]	5.7 [0.7; 19.2]	21.9 [9.3; 40.0]
Moxifloxacin/48 h	32	35	ROC01	29	84.9 [76.0; 91.5]	5.7 [0.7; 19.2]	21.9 [9.3; 40.0]
Moxifloxacin/72 h	64	48	Youden index	33	91.0 [84.9; 95.3]	0.0 [0.0; 5.6]	14.6 [6.1; 27.8]
Moxifloxacin/72 h	64	48	ROC01	32	90.3 [84.0; 94.7]	0.0 [0.0; 5.6]	12.5 [4.7; 25.4]

FDA: U.S. Food and Drug Administration; CA: category agreement; vmj: very major discrepancies rate; maj: major discrepancies rate. 95%CI: 95% confident interval. In bold: conditions that reached the FDA acceptable performance criteria

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ISSN: 1476-0711

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