Table 3. Antimicrobial resistance and gene patterns of Salmonella Typhimurium variants

Ann Clin Microbiol 2026;29(3):14. Molecular epidemiological characteristics of monophasic Salmonella enterica serovar Typhimurium variants in Korea

Table 3. Antimicrobial resistance and gene patterns of Salmonella Typhimurium variants

Antimicrobial agent	I 4,[5],12:i:1,2 (Typhimurium)			I 4,[5],12:-:-	I 4,[5],12:i:-
Antimicrobial agent	P1 (n = 32)	P2 (n = 6)	Total (n = 38)	P1 (n = 4)	P1 (n = 2)	P5 (n = 72)	P8 (n = 29)	P9 (n = 28)	Total (n = 131)	P-value (P5 vs. P8)
Amikacin^a)	0	0	0	0	0	0	0	0	0	−
Ampicillin	46.9	50.0	47.4	25.0	0	91.7	79.3	3.6	68.7	0.098
Azithromycin	0	0	0	0	0	2.8	0	0	1.5	1.000
Cefotaxime	3.1	0	2.6	0	0	13.9	41.4	3.6	17.6	0.006
Cefoxitin^a)	3.1	0	2.6	0	0	4.2	0	0	2.3	0.555
Ceftazidime^a)	0	0	0	0	0	4.2	37.9	0	10.7	< 0.001
Ceftriaxone	3.1	0	2.6	0	0	11.1	41.4	3.6	16.0	0.002
Chloramphenicol	25.0	50.0	28.9	25.0	0	31.9	41.4	0	26.7	0.489
Ciprofloxacin (Intermediate rates, %)	6.3 (40.6)	16.7 (50.0)	7.9 (42.1)	0 (100)	0 (0)	0 (27.8)	6.9 (31.0)	0 (0)	1.5 (22.1)	0.080
Colistin^b)	0	0	0	0	0	0	0	7.1	1.5	−
Gentamicin^a)	28.1	0	23.7	25.0	0	8.3	0	0	4.6	0.178
Imipenem	0	0	0	0	0	0	0	0	0	−
Nalidixic acid^a)	43.8	0	36.8	100	0	0	3.4	0	0.8	0.287
Streptomycin^a)	21.9	33.3	23.7	25.0	0	86.1	79.3	3.6	65.6	0.385
Tetracycline	34.4	33.3	34.2	0	0	84.7	75.9	0	63.4	0.389
Trimethoprim–sulfamethoxazole	12.5	50.0	18.4	0	0	27.8	0	0	15.3	< 0.001

Values are presented as percentages of resistant isolates unless otherwise indicated.
^a)Clinical and Laboratory Standards Institute (CLSI) breakpoints have not been established for these antimicrobial agents; the interpretive standards used are the National Antimicrobial Resistance Monitoring System (NARMS)-established breakpoints for resistance monitoring, which should not be used to predict clinical efficacy.
^b)European Committee on Antimicrobial Susceptibility Testing, 2026.