The scope of this study was to assess the frequency of erythromycin and tetracycline resistant lactobacilli in the production chain (skin, minced meat, and stools of eight swine, the natural casing, and the final product at days 0, 21, 35, and 45 of ripening) of a Protected Designation of Origin dry sausage from the North of Italy and in the end products. We isolated colonies of lactobacilli from selective medium supplemented with erythromycin or tetracycline and the most frequently antibiotic resistant species isolated were Lactobacillus sakei, Lactobacillus curvatus and Lactobacillus plantarum The most frequent resistance genes in process line strains were tet(M) and erm(B) while tet(W) and erm(B) were common in strains isolated from swine stools. This study provides evidence of the presence of tetracycline and, to a lesser extent, erythromycin resistant lactobacilli in fermented dry sausages produced in Northern Italy. Although these antibiotic resistant lactobacilli could serve as reservoir organisms, in our study 80% of salami could be considered as safe even though 20% could represent a border line situation regarding the possibility of transferring antibiotic resistant genes to pathogens.
Lo scopo di questo lavoro di tesi era di stabilire la frequenza di lattobacilli resistenti all’eritromicina e alla tetraciclina sia nel prodotto finito che nella filiera di produzione di un salame DOP del Nord Italia. Il controllo della filiera produttiva comprendeva la pelle, la carne macinata e le feci di otto suini mentre il prodotto finito era analizzato a 0, 21, 35 e 45 giorni di stagionatura. Sono state isolate colonie di lattobacilli da terreni di coltura selettivi addizionati di antibiotici. Le specie antibiotico resistenti più frequentemente isolate erano Lactobacillus sakei, Lactobacillus curvatus and Lactobacillus plantarum. I geni che con maggior frequenza sono stati evidenziati nei ceppi isolati dalla filiera e nel prodotto finito erano tet(M) ed erm(B) mentre tet(W) ed erm(B) lo erano per i ceppi isolati dalle feci. Questo studio ha consentito di fornire dati circa la presenza e la diffusione di lattobacilli tetraciclina ed eritromicina resistenti in un salame tipico del Nord Italia. I lattobacilli antibiotico resistenti potrebbero trasferire ad altri batteri, patogeni o non patogeni, i geni responsabili della resistenza stessa. Alla luce di tutto questo l’80% dei salami analizzati possono essere considerati sicuri da questo punto di vista mentre il 20% può essere valutato come un prodotto a rischio anche se la situazione non è ancora preoccupante.
ZONENSCHAIN, DANIELA, Erythromycin and tetracycline resistant lactobacilli in the production of a typical dry sausage from the north of Italy, MORELLI, LORENZO, Università Cattolica del Sacro Cuore Piacenza:Ciclo XXI [https://hdl.handle.net/10807/286095]
Erythromycin and tetracycline resistant lactobacilli in the production of a typical dry sausage from the north of Italy
Zonenschain, Daniela
2009
Abstract
The scope of this study was to assess the frequency of erythromycin and tetracycline resistant lactobacilli in the production chain (skin, minced meat, and stools of eight swine, the natural casing, and the final product at days 0, 21, 35, and 45 of ripening) of a Protected Designation of Origin dry sausage from the North of Italy and in the end products. We isolated colonies of lactobacilli from selective medium supplemented with erythromycin or tetracycline and the most frequently antibiotic resistant species isolated were Lactobacillus sakei, Lactobacillus curvatus and Lactobacillus plantarum The most frequent resistance genes in process line strains were tet(M) and erm(B) while tet(W) and erm(B) were common in strains isolated from swine stools. This study provides evidence of the presence of tetracycline and, to a lesser extent, erythromycin resistant lactobacilli in fermented dry sausages produced in Northern Italy. Although these antibiotic resistant lactobacilli could serve as reservoir organisms, in our study 80% of salami could be considered as safe even though 20% could represent a border line situation regarding the possibility of transferring antibiotic resistant genes to pathogens.File | Dimensione | Formato | |
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