Biochemical characterization and antibiotype of Clostridium botulinum strains isolated from infant botulism cases

LÚQUEZ C, SAGUA MD, TELECHEA A, CABALLERO P, DE JONG LIT, BIANCO MI, DEGARBO SM, RAMOS G, FERNÁNDEZ RA

Mendoza, Argentina

Otro; XXI Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2003

Clostridium botulinum (Cb) intestinal colonization and later absorption of its toxin cause infant botulism (IB). It affects infants under one year of age. Specific characteristics of these strains are unknown. Our aim was to determine in Cb strains from Mendoza IB cases: antimicrobial resistance pattern and biochemical characteristics. We studied 21 serotype A Cb strains: 13 from IB cases, 4 from food-borne botulism, 2 from Matricaria spp and two reference strains. Minimal Inhibitorial Concentration (MIC) was determinated by agar dilution (NCCLS) for ampicillin (AMC), amoxicillin (AMX) and ampicillin-sulbactam (AMC-S).  Biochemical test included: lipase, lecithinase, proteolysis, carbohydrate fermentation, indole, H2S and urease enzyme production, gelatin and esculin hydrolysis, nitrate reduction, fatty acids production (gas cromatography) and hemagglutinin detection. AMC, AMX and AMC-S MIC were between 0,06 and 2 µg/ml. According to the biochemical tests all the strains corresponded to Group I (proteolytic strains) and were  hemagglutinin negative, except one reference strain that showed a titer of 64. So far, these results suggest that antimicrobial susceptibility and biochemical characteristics do not represent significative differences to characterize these strains.  For this purpose, hemagglutinin production could be used