Shiga toxin-producing Escherichia coli in beef retail markets from Argentina.
Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens that cause mild or serious diseases and can lead to people death. This study reports the prevalence and characteristics of STEC O157 and non-O157 in commercial ground beef and environmental samples, including meat table, knife, meat mincing machine, and manipulator hands (n = 450) obtained from 90 retail markets over a nine-month period. The STEC isolates were serotyped and virulence genes as stx (Shiga toxin), rfb(O157)] (O157 lipopolysaccharide), fliC(H7) (H7 flagellin), eae (intimin), ehxA (enterohemolysin) and saa (STEC autoagglutinating adhesin), were determined. STEC O157 were identified in 23 (25.5%) beef samples and 16 (4.4%) environmental samples, while STEC non-O157 were present in 47 (52.2%) and 182 (50.5%), respectively. Among 54 strains isolated, 17 were STEC O157:H7 and 37 were STEC non-O157. The prevalent genotype for O157 was stx(2)/eae/ehxA/fliC(H7) (83.4%), and for STEC non-O157 the most frequent ones were stx(1)/stx(2)/saa/ehxA (29.7%); stx(2) (29.7%); and stx(2)/saa/ehxA (27%). None of the STEC non-O157 strains were eae-positive. Besides O157:H7, other 20 different serotypes were identified, being O8:H19, O178:H19, and O174:H28 the prevalent. Strains belonging to the same serotype could be isolated from different sources of the same retail market. Also, the same serotype could be detected in different stores. In conclusion, screening techniques are increasingly sensitive, but the isolation of STEC non-O157 is still a challenge. Moreover, with the results obtained from the present work, although more studies are needed, cross-contamination between meat and the environment could be suspected.
Laboratorio de Microbiología de Alimentos, Instituto de Genética Veterinaria "Ing. Fernando N. Dulout", Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, CCT-La Plata, CONICET Buenos Aires, Argentina.
Victoria
V
Brusa
Virginia
V
Aliverti
Florencia
F
Aliverti
Emanuel E
EE
Ortega
Julian H
JH
de la Torre
Luciano H
LH
Linares
Marcelo E
ME
Sanz
Analía I
AI
Etcheverría
Nora L
NL
Padola
Lucía
L
Galli
Pilar
P
Peral García
Julio
J
Copes
Gerardo A
GA
Leotta
D001118:Argentina; D004783:Environmental Microbiology; D005408:Flagellin / Q000235:genetics; D005506:Food Contamination; D019649:Food Industry; D005838:Genotype; D006801:Humans; D008460:Meat / Q000382:microbiology*; D017720:Molecular Epidemiology; D019081:O Antigens / Q000235:genetics; D015995:Prevalence; D012703:Serotyping; D054323:Shiga-Toxigenic Escherichia coli / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D037521:Virulence Factors / Q000235:genetics
D019081:O Antigens; D037521:Virulence Factors; D005408:Flagellin
Argentina; STEC; environmental samples; raw ground beef; retail markets