The aim of this study was to detect the plasmid profiles, haemolytic activity and antibiotic susceptibility patterns of 47 Enterococcus strains isolated from Turkish Tulum cheese. Enterococcus strains were found to comprise 1-9 plasmids with molecular weight from 2.0 to 47.6 kb. None of the Enterococcus strains displayed haemolytic activity. The Enterococcus strains were found mostly resistant to tetracycline (30 lg) followed by high-level streptomycin (300 lg). The Enterococcus faecalis strains were found to be highly resistant to antibiotics than Enterococcus faecium and Enterococcus durans strains. In total, 4.3% of the strains exhibited multiple antibiotic resistance patterns.
The aim of this study was to evaluate several genetic and phenotypic traits of clinical significance in 21 Enterococcus faecium and seven E. faecalis strains previously isolated from Turkish Tulum Cheese. Enterococcus strains were tested for the presence of 14 virulence genes and two vancomycin resistance genes by polymerase chain reaction (PCR). Biogenic amine production was also investigated by decarboxylase medium and PCR. Investigation of virulence factors by PCR amplification revealed the presence of genes encoding for gelatinase (gelE), cell wall adhesin (efaAfm and efaAfs), sex pheromone (ccf), cell wall‐associated protein (espfm and espfs) and aggregation substance (agg). Other presumed virulence genes (cpd, cob, cad, ace, cylM, cylB and cylA) were not detected. At least one virulence gene was detected in all strains. The ccf (85.7%), efaAfm (75.0%) and gelE (32.1%) were detected most frequently present virulence genes in enterococcal strains. Phenotypic gelatinase testing revealed the existence of apparently silent gelE gene. None of the strains carried the vanA and vanB genes. Enterococcus strains did not decarboxylate histidine, lysine or ornithine, but the majority of strains (92.9%) produced tyramine from tyrosine. The tyrosine decarboxylase gene (tdc) was detected in all tyraminogenic strains.
Practical Application
Enterococci are lactic acid bacteria that are important both in food and clinical microbiology. Enterococci species especially E. faecium and E. faecalis play an important role in the development of sensory characteristics of different traditional fermented foods such as dairy and meat products. On the other hand, E. faecium and E. faecalis are recognized as nosocomial pathogens. Results of this study indicated that E. faecium and E. faecalis strains isolated from Turkish Tulum Cheese carried some virulence genes and most of them produce tyramine. The findings of our study suggest that E. faecium and E. faecalis strains isolated from Turkish Tulum Cheese may be potential risk factors for consumer health. For this reason, use of Enterococcus strains as starter cultures requires thorough safety evaluation.
The aim of this work was to detect technological characteristics of fifty strains of lactococci previously isolated in Turkey in order to use them as components of starter formulations. All the lactococcal strains were low acid producers from lactose except L. lactis subsp. lactis MBLL9. 22, 17 and 11 strains of L. lactis presented low, moderate and strong proteolytic activity, respectively. Three out of 50 strains (L. lactis subsp. lactis MBLL1, MBLL9 and MBLL57) were determined to be bacteriocin producers. The strains L. lactis subsp. lactis MBLL1 and MBLL9 were found to be lacticin 481-like producers, whereas MBLL57 was a nisin-like producer, according to their partial characterization data. L. lactis strains were tested against 61 lactic phages for their phage-resistance properties. Eleven strains exhibited a sensitive phenotype against different phages, whereas the remaining 39 strains were completely resistant to all phages. Among the L. lactis subsp. lactis biovar. diacetylactis strains, 5 strains were defined as high, 3 strains as medium and 7 strains as low-level diacetyl producers. L. lactis strains were found to have 1-10 plasmids with molecular weights from 1.9 to 29.2 kb. Lactococcus lactis / technological characteristics / plasmid / starter culture / wild strain
The aim of this study was to isolate enterococci in Sucuk, a traditional Turkish dry-fermented sausage and to analyze isolates for their biodiversity, antibiotic resistance patterns and the presence of some antibiotic resistance genes. A total of 60 enterococci strains were isolated from 20 sucuk samples manufactured without using a starter culture and they were identified as E. faecium (73.3%), E. faecalis (11.7%), E. hirae (8.3%), E. durans (3.3%), E. mundtii (1.7%) and E. thailandicus (1.7%). Most of the strains were found resistant to rifampin (51.67%) followed by ciprofloxacin (38.33%), nitrofurantoin (33.33%) and erythromycin (21.67%). All strains were found susceptible to ampicillin. Only E. faecium FYE4 and FYE60 strains displayed susceptibility to all antibiotics. Other strains showed different resistance patterns to antibiotics. E. faecalis was found more resistant to antibiotics than other species. Most of the strains (61.7%) displayed resistance from between two and eight antibiotics. The ermB, ermC, gyrA, tetM, tetL and vanA genes were detected in some strains. A lack of correlation between genotypic and phenotypic analysis for some strains was detected. The results of this study indicated that Sucuk manufactured without using a starter culture is a reservoir of multiple antibiotic resistant enterococci. Consequently, Sucuk is a potential reservoir for the transmission of antibiotic resistance genes from animals to humans.
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