Detection and Characterization of Shiga Toxin Producing Escherichia coli, Salmonella spp., and Yersinia Strains from Human, Animal, and Food Samples in San Luis, Argentina

Table 2

Frequency of detection of STEC, Salmonella serotypes, and Yersinia species in samples of diverse origin analyzed in this study.

Source	Number of; samples	STEC		Salmonella spp.		Yersinia species
		Positive samples (% ± 1.96SE)*		Positive samples (% ± 1.96SE)*	Serovar; (number of strains)	Positive samples (% ± 1.96SE)*	Species	Bioserovar (No. strains)
		Culture	PCR
Human stools	70	1 (1.4 ± 2.8)	—	1 (1.4 ± 2.8)	S. Typhimurium (1)	—	—
Animal stools:	167
feedlot bovines	61	—	2 (3.3 ± 4.6)	—		—
grazing bovines	68	—	1 (1.5 ± 3.0)	—		—
porcines	20	—	—	—		—
ovines	10	—	—	—		—
goats	6	—	—	—		—
equines	2	—	—	—		—
Samples of animal origin for human consumption:	216
chicken carcasses	80	—	—	—		6 (7.5 ± 6.0)	Y.  enterocolitica; Y. intermedia	B1A O:12,25-12,26 (2); B1A O:7,8-8-8,19 (2); B6 O:17 (1); B4 O:40 (1)
porcine skin and bones	10	—	—	—		3 (30 ± 35)	Y. enterocolitica	B1A O:7,8-8-8,19 (3)
goat cheeses	30	—	—	—		—
fresh sausages	90	—	—	—		—
wild boars	3
tonsils	3	—	—	1 (33 ± 66)	S. Newport (1); S. Gaminara (1)	—
tongues	3	—	—	1 (33 ± 66)	S. Gaminara (1)	—
Total	453	4 (0.9 ± 0.9)		3 (0.7 ± 0.8)		9 (2.0 ± 1.3)

^∗(%): percentage corresponding to positive samples/total samples of the same type; (%): percentage corresponding to total positive samples for each pathogen/total of samples. In both cases, 1.96SE is the value ( 0.05) multiplied by the standard error.