Table 4.

Comparison between microdilution-based phenotypic resistance and genotype-predicted resistance according to AMR genetic determinant for 219 C. jejuni isolates.

Antibiotic agent	Phenotypic profile	No. isolates (%)	AMR determinant detected	AMR gene present/absent	Correlation ratea (%)	Sen.b (%)	Spec.c (%)	PPVd (%)	NPVe (%)
Ciprofloxacin	Resistant	170 (77.6)	gyrA T86I	168/2	98.2	98.8	95.9	98.8	95.9
	Susceptible	49 (22.4)		2/47
Nalidixic acid	Resistant	169 (77.2)	gyrA T86I	168/1	98.6	99.4	96.0	98.8	98.0
	Susceptible	50 (22.8)		2/48
Streptomycin	Resistant	38 (17.4)	aadE	36/2	99.1	94.7	100.0	100.0	98.9
	Susceptible	181 (82.6)		0/181
Gentamicin	Resistant	0	aph(3′)-IIIa	0/0	100.0	100.0	100.0	100.0	100.0
	Susceptible	219 (100)		0/219
Erythromycin	Resistant	2 (0.9)	23S rRNA A2075G	2/0	100.0	100.0	100.0	100.0	100.0
	Susceptible	217 (99.1)		0/217
Tetracycline	Resistant	185 (84.5)	tet(O)	179/6	96.8	96.8	97.1	99.4	84.6
	Susceptible	34 (15.5)		1/33
Total	Resistant	564 (42.9)		553/11	98.8	98.0	99.3	99.1	98.5
	Susceptible	750 (57.1)		5/745

AMR, Antimicrobial resistance; Sen., Sensitivity; Spec., Specificity; PPV, Positive predictive value; NPV, Negative predictive value.

^aCalculated as the sum of true positive and true negative divided by all tested isolates.

^bCalculated by dividing true positive by the sum of true positive and false positive.

^cCalculated by dividing true negative by the sum of true negative and false negative.

^dCalculated by dividing true positive by the sum of true positive and false negative.

^eCalculated by dividing true negative by the sum of true negative and false positive.