Stx genotypes and antimicrobial resistance profiles of Shiga toxin-producing Escherichia coli strains isolated from human infections, cattle and foods in Brazil

• Published in: FEMS microbiology letters 2006-06, Vol.259 (2), p.234-239
• Main Authors: Cergole-Novella, Maria Cecília, Nishimura, Lucilia S., Irino, Kinue, Vaz, Tânia Mara I., De Castro, Antônio Fernando Pestana, Leomil, Luciana, Guth, Beatriz Ernestina C.
• Format: Article
• Language: English
• Subjects: Action of physical and chemical agents on bacteria; Animals; Antiinfectives and antibacterials; Antimicrobial agents; Antimicrobial resistance; antimicrobial susceptibility; Bacteria; Bacteriology; Biological and medical sciences; Brazil; Cattle; Drug resistance; Drug Resistance, Bacterial - genetics; E coli; Escherichia coli; Escherichia coli - classification; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - isolation & purification; Escherichia coli Infections - microbiology; Food; Food Microbiology; Fundamental and applied biological sciences. Psychology; Genetics; Genotype; Genotypes; Humans; Metabolism. Enzymes; Microbiology; Serotypes; Serotyping; Shiga toxin; Shiga Toxin 1 - biosynthesis; Shiga Toxin 1 - genetics; Shiga Toxin 2 - biosynthesis; Shiga Toxin 2 - genetics; Shiga toxin‐producing Escherichia coli; Strains (organisms); Streptomycin; stx subtypes; Toxins
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2006.00272.x

Abstract A total of 107 Shiga toxin-producing Escherichia coli strains (STEC) isolated from different origins in São Paulo, Brazil, and belonging to different serotypes were characterized regarding stx subtypes and susceptibility to antimicrobial agents. Most of the human STEC strains harbored stx1 (85.7%), while stx2, associated or not to stx1, was identified preferentially in the animal and food strains. None of the STEC strains carried stx1c. Some genotypes occurred exclusively among strains of bovine origin as stx2c, stx1+2+2c (16.5% each), and stx2d (0.9%), whereas stx2+2c(2vha) was only identified among the O157:H7 human strains. Moreover, the stx2c(2vhb) subtype was found more frequently among bovine than human strains (39% vs. 4.8%). The highest frequencies of susceptibility to antimicrobial agents were observed among bovine (87%) and food (100%) STEC strains, while 47.6% of the human isolates were resistant to at least one drug. Multiresistance occurred among O111 STEC strains from human and bovine origin. The antimicrobials to which resistance was most frequently observed were tetracycline (90%) and streptomycin (75%) among human strains, and also sulphazotrin (88%) in animal strains. A few serotypes were commonly identified among STEC strains isolated from diverse sources in Brazil, but in general the strains presented distinct stx subtypes and/or antimicrobial resistance profiles.