Erythromycin- and tetracycline-resistant lactobacilli in Italian fermented dry sausages.
OBJECTIVE
To assess the frequency of erythromycin- and tetracycline-resistant lactobacilli in Italian fermented dry sausages.


RESULTS
We isolated lactobacilli colonies from 20 salami from the north of Italy (Piacenza province) using selective medium supplemented with erythromycin or tetracycline; we determined the minimum inhibitory concentration and searched for selected erythromycin and tetracycline resistance genes. A total of 312 lactobacilli colonies were genetically ascribed to 60 different strains belonging to seven Lactobacillus species. Lactobacillus sakei, Lactobacillus curvatus and Lactobacillus plantarum were the most frequently found species. Thirty strains (50%) were phenotypically resistant to erythromycin, 45 (75%) to tetracycline and 27 (45%) were resistant to both. The most frequently detected resistance genes were tet(M) and erm(B).


CONCLUSIONS
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.


CONCLUSIONS
Although these antibiotic-resistant lactobacilli could serve as reservoir organisms, in our study, 16 of 20 salami could be considered safe in regard to possible antibiotic resistance gene transfer to pathogens, whereas 4 of 20 could represent a borderline situation.
Istituto di Microbiologia, Facoltà di Agraria, Università Cattolica del Sacro Cuore, Piacenza, Italy. daniela.zonenschain@unicatt.it
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Rebecchi
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Morelli
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D004917:Erythromycin / Q000494:pharmacology*; D005516:Food Microbiology; D005798:Genes, Bacterial / Q000235:genetics; D007558:Italy; D007778:Lactobacillus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D008461:Meat Products / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D013752:Tetracycline / Q000494:pharmacology*; D013753:Tetracycline Resistance / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004917:Erythromycin; D013752:Tetracycline