Prevalence, virulence potential, and pulsed-field gel electrophoresis profiling of Shiga toxin-producing Escherichia coli strains from cattle

Table 4 Phenotypic and genotypic antimicrobial resistance profiles of STEC isolates

Antimicrobial class	Phenotypic profiles			Genotypic profiles
	Antimicrobial^a	No. of STEC isolates^b (%)		Antimicrobial resistance gene^c	No. of STEC isolates (%)
	Antimicrobial^a	STEC O157	STEC non-O157^b	Antimicrobial resistance gene^c	STEC O157	STEC non-O157
Β-lactams	Ampicillin	0 (0.0)	4 (14.3)	ampC	35 (100.0)	28 (100.0)
Β-lactams	Cefotaxime^d	0 (0.0)	1 (3.6)	Bla _TEM	0 (0.0)	11 (36.3)
Tetracycline	Tetracycline	0 (0.0)	5 (17.9)	tetB	0 (0.0)	4 (14.3)
				tetC	0 (0.0)	3 (10.7)
				tetE	34 (97.1)	0 (0.0)

^a All STEC showed susceptibility on chloramphenicol, imipenem, amikacin, amoxicillin–clavulanic acid, ceftazidime, gentamicin, nalidixic acid, trimethoprim–sulfamethoxazole, ceftriaxone, aztreonam, and cefpodoxime on standard disk-diffusion test
^b Antimicrobial resistance profiles were tested for 35 and 28 STEC O157 and non-O157 strains, respectively
^c Antimicrobial resistance genes of tetA, tetD, tetG, cat, cml, bla _OXA , bla _CMY, and qnr were not detected from all STEC isolates
^d Four STEC O157 and five non-O157 showed intermediate resistance to cefotaxime

ISSN: 1757-4749