[Study of phenotypical and antimicrobial susceptibility markers in enteric Escherichia coli strains]. / Estudio de marcadores fenotípicos y de susceptibilidad antimicrobiana en cepas de Escherichia coli entéricas.

Forty strains of Escherichia coli isolated from children under 5 years of age with acute diarreas, coming from different provinces of the country , were analyzed. Four important phenotypical determinants were tested: sorbosa, sorbitol, enterohemolysin and 0157:H7 serology, in order to select those strains from enterohemorrhagic or Shiga toxin-producing category. Likewise, they were characterized by biotyping and antimicrobial susceptibility methods. The use of phenotypical tests showed six strains with presumptive characteristics, four of which were most likely to be Shiga toxin-producing strains. In antimicrobial susceptibility test, the strains showed high resistance mainly to ampicillin and trimethrophin-sulfamethoxasole. Another interesting finding were intermediate resistance and susceptibility values to augmentin, aztreonan and ceftriaxone. There were 12 antimicrobial resistance patterns of which 10 were multi-resistant.