Tylosin exposure reduces the susceptibility of Salmonella Typhimurium to florfenicol and tetracycline

BMC Veterinary Research

Table 1 The MICs (μg/mL) of the selected antibiotics against S. Typhimurium strains before and after exposure to tylosin (taken after 12 and 24 h of incubation) in the in vitro dynamic model and in the presence and absence of an efflux pump inhibitor

Antibiotics	S. Typhimurium (ATCC-14028)				S. Typhimurium (LVPP-STI2)				S. Typhimurium (LVPP-STI15)
	Pre		Post		Pre		Post		Pre		Post
	WEI	EI	WEI	EI	WEI	EI	WEI	EI	WEI	EI	WEI	EI
TET	2	2	128	8	1	1	128	4	256	64	512	128
MBF	0.03	0.03	0.06	0.06	0.03	0.03	0.06	0.03	0.5	0.13	2	0.26
FFL	4	4	32	8	4	2	32	8	2	1	8	2
TMP	0.04	0.04	0.04	0.04	0.04	0.04	0.16	0.16	> 256	> 256	> 256	> 256
STR	32	32	512	64	1024	512	1024	1024	1024	1024	> 1024	> 1024
SMT	64	64	64	64	> 1024	1024	> 1024	> 1024	> 1024	> 1024	> 1024	> 1024
TYL	1024	512	1024	512	1024	1024	1024	1024	1024	1024	1024	1024

SMX = sulfamethoxazole, TET = tetracycline, FFL = florfenicol, TMP = trimethoprim, MBF = marbofloxacin, STR = streptomycin, and TYL = tylosin, WEI = without the efflux pump inhibitor, EI = together with the efflux pump inhibitor (Phe-Arg-β-naphthylamide, 40 μg/mL). The MIC values were similar for both time points (12 vs 24 h)

ISSN: 1746-6148