Putative virulence properties of Aeromonas strains isolated from food, environmental and clinical sources in Italy: a comparative study |
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Authors: | Ottaviani Donatella Parlani Chiara Citterio Barbara Masini Laura Leoni Francesca Canonico Cristina Sabatini Luigia Bruscolini Francesca Pianetti Anna |
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Affiliation: | a Istituto Zooprofilattico dell'Umbria e delle Marche- Laboratorio Nazionale di Riferimento Contaminanti Batteriologici dei Molluschi Bivalvi (CEREM)- Sezione di Ancona, Via Cupa di Posatora 3, 60131 Ancona, Italyb Dipartimento di Scienze Biomolecolari - Sezione di Scienze Tossicologiche, Igienistiche e Ambientali, Università degli Studi di Urbino “Carlo Bo”, Via S. Chiara 27, 61029 Urbino (PU), Italy |
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Abstract: | The distribution of virulence properties in 142 strains of Aeromonas isolated from diarrhoeic patients, food and surface water in Italy and identified by biochemical and molecular methods was investigated. The virulence properties studied were the presence of genes for the aerolysin (aerA), heat-stable cytotonic enterotoxin (ast), heat-labile cytotonic enterotoxin (alt), cytotoxic enterotoxin (act); and cytotoxicity for Vero cells and adhesion on Hep-2 cells. A. hydrophila and A. caviae were the species most commonly isolated from clinical and environmental samples (9/30; 30.0% and 5/27; 18.5%, respectively) while mesophilic A. salmonicida was most common in food samples (19/80; 23.7%). Out of 142 strains, 86 (60.6%) were positive for at least one of the virulence properties. All the toxin genes were present in 4/18 (22.3%) of clinical strains. Most of the food isolates (54/55; 98.2%) were cytotoxic and most of the environmental strains (12/13; 92.3%) were adhesive. The aerA gene was present in most toxigenic strains (72/86; 83.7%), irrespective of their origin. The growth temperature affected the expression of cytotoxicity and adhesivity. Aeromonas strains from food and surface water frequently had toxin gene patterns similar to those of clinical strains and expressed virulence properties at human body temperature. These findings indicate that aeromonads have the potential to cause human illness and confirm the role of food and water as vehicles for Aeromonas diseases. |
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Keywords: | Aeromonas Toxin gene Virulence properties Cytotoxicity Adhesivity |
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