Molecular typing of antimicrobial-resistant Shiga-toxin-producing Escherichia coli strains (STEC) in Brazil

• Published in: Research in microbiology Vol. 162; no. 2; pp. 117 - 123
• Main Authors: Cergole-Novella, Maria Cecilia, Pignatari, Antonio Carlos Campos, Castanheira, Mariana, Guth, Beatriz Ernestina Cabilio
• Format: Journal Article
• Language: English
• Published: Issy-les-Moulineaux Elsevier SAS 01.02.2011; Elsevier Masson
• Subjects: Ampicillin; Animals; Anti-Bacterial Agents - pharmacology; Bacterial Typing Techniques; Bacteriology; Biological and medical sciences; Brazil; Cattle; Cattle Diseases - microbiology; Class 1 integron; Conjugation; Conjugation, Genetic; Drug resistance; Drug Resistance, Bacterial - genetics; Electrophoresis, Gel, Pulsed-Field; Escherichia coli; Escherichia coli Infections - microbiology; Escherichia coli Infections - veterinary; Escherichia coli Proteins - genetics; Feces; Fundamental and applied biological sciences. Psychology; Humans; Infection; Integrase; Integrons - genetics; Microbial Sensitivity Tests; Microbiology; Miscellaneous; Molecular Typing; Phylogenetic background; Phylogeny; Plasmids; Public health; Resistance genes; Serotypes; Serotyping; Shiga-Toxigenic Escherichia coli - classification; Shiga-Toxigenic Escherichia coli - drug effects; Shiga-Toxigenic Escherichia coli - genetics; Shiga-Toxigenic Escherichia coli - isolation & purification; Shiga-toxin-producing Escherichia coli; Streptomycin; Tetracyclines; trimethoprim-sulfamethoxazole; Typing; Brazil; South America; America; Class 1 integron; Phylogenetic background; Shiga-toxin-producing Escherichia coli; Resistance genes; Escherichia coli; Genotype; Phylogeny; Antimicrobial agent; Strain; Resistance; Gene; Integron; Molecular epidemiology; Bacteria; Shiga like toxin; Enterobacteriaceae
• ISSN: 0923-2508; 1769-7123
• DOI: 10.1016/j.resmic.2010.09.022

Antimicrobial resistance patterns and molecular characteristics were determined in thirty-two Shiga-toxin-producing Escherichia coli (STEC) strains previously identified in São Paulo State associated with human infections ( n = 21) and in cattle feces ( n = 11). The highest resistance rates were identified for tetracycline (100%), streptomycin (78%) and trimethoprim–sulfamethoxazole (56%). Eleven STEC strains showed resistance to ampicillin and carried bla TEM that was confirmed as bla TEM-1 in one representative isolate. The class 1 integrase gene ( intI1) was detected in seven (22%) strains, and most of them belonged to the O111:H8 serotype. The class 1 integron was located on plasmids in five of the seven STEC strains, and conjugation assays confirmed the plasmid support of those resistant determinants. STEC strains were genetically classified into the B1 group, and PFGE analysis showed that most of the strains in each serogroup were grouped into the same cluster (80–97% similarity). The presence of a class 1 integron and bla TEM-1 genes is described for the first time among STEC isolates in Brazil and clearly represents a public health concern.