Antimicrobial susceptibility of shiga toxin producing E coli (STEC) strains isolated from human infections and food

• Published in: Revista medíca de Chile Vol. 132; no. 10; pp. 1211 - 1216
• Main Authors: Reyes, Marcelo S, Durán, Claudia T, Prado, Valeria J
• Format: Journal Article
• Language: Spanish
• Published: Chile 01-10-2004
• Subjects: Anti-Bacterial Agents - pharmacology; Anti-Bacterial Agents - therapeutic use; Diarrhea - microbiology; Drug Resistance, Bacterial; Escherichia coli - drug effects; Escherichia coli - metabolism; Escherichia coli Infections - microbiology; Escherichia coli O157 - drug effects; Escherichia coli O157 - metabolism; Hemolytic-Uremic Syndrome - microbiology; Humans; Meat Products - microbiology; Shiga Toxins - biosynthesis
• ISSN: 0034-9887

Shiga toxin-producing E coli (STEC) are zoonotic pathogens associated to sporadic episodes of bloody diarrhea, foodborne outbreaks, and Hemolytic Uremic Syndrome (HUS), with worldwide public health impact. Antibiotic use in STEC infections is controversial because of the potential to increase production and secretion of Shiga toxins.
To study the in vitro antimicrobial susceptibility profile of STEC.
The in vitro susceptibility profile against 10 antimicrobials of STEC strains isolated from 29 meat products, 20 patients with diarrhea and 9 HUS patients was studied. Minimal Inhibitory Concentrations (microg/ml) by agar dilution method for ampicillin, cloramphenicol, ciprofloxacin, amikacin, gentamycin, cotrimoxazol, ceftriaxone, tetracycline, fonsfomycin and azihromycin were measured according to NCCLS recommendations.
Strains from patients with diarrhea or HUS were all susceptible to the 10 antimicrobials and only 13.7% had intermediate resistance to cloramphenicol. Strains from meat products had a similar susceptibility profile, with only 3.5% resistance to tetracycline, 3.5% intermediate resistance to cloramphenicol and 7% to fosfomycin. All 58 strains were considered resistant to azithromycin (MIC >32 microg/ml).
Similarity of susceptibility profiles between STEC strains from human and food origin suggests a role of food chain in transmission to humans.