Tyramine-producing enterococci are equally detected on tyramine production medium, by quantification of tyramine by HPLC, or by<i>tdc</i>gene-targeted PCR

Bhardwaj, Arun; Gupta, Hittu; Iyer, Ramya; Kumar, Naresh; Malik, R. K.

doi:10.1051/dst/2009040

Cited by 7 publications

(8 citation statements)

References 28 publications

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“…In any event, the present work highlights a good correlation between the results of molecular and functional analysis of BA-producing capacity. All the BA-producing strains returned positive PCR results, indicating that this cultureindependent technique is suitable for assessing this property in potential LAB starter strains [28].…”

Section: Resultsmentioning

confidence: 90%

“…However, culture-independent methods based on PCR techniques, aimed to detect the genetic determinants involved in the synthesis of BA, are now regarded as the most suitable for screening collections of isolates [26]. Agreement between the results obtained by analytical and molecular methods strengthens the case for the use of the latter [27,28].…”

Section: Introductionmentioning

confidence: 99%

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Genetic and functional analysis of biogenic amine production capacity among starter and non-starter lactic acid bacteria isolated from artisanal cheeses

Ladero

Martín

Redruello

et al. 2015

Eur Food Res Technol

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This work reports the capacity of strains of starter and non-starter LAB belonging to nine species of the genera Lactobacillus, Lactococcus, Streptococcus and Leuconostoc (all isolated from artisanal cheeses) to produce histamine, tyramine, putrescine and β-phenylethylamine, the biogenic amines (BA) most commonly found in dairy products. Production assays were performed in liquid media supplemented with the appropriate precursor amino acid; culture supernatants were then tested for BA by (U)HPLC. In addition, the presence of key genes involved in the biosynthetic pathways of the target BA, including the production of putrescine via the agmatine deiminase pathway, was assessed by PCR. Twenty strains were shown to have genes involved in the synthesis of BA; these belonged to the species Lactobacillus brevis (4), Lactobacillus curvatus (3), Lactococcus lactis (11) and Streptococcus thermophilus (2). With the exception of the two S. thermophilus strains, all those possessing genes involved in BA production synthesized the corresponding compound. Remarkably, all the putrescine-producing strains used the agmatine deiminase pathway. Four Lb. brevis and two Lb. curvatus strains were found able to produce both tyramine and putrescine. There is increasing interest in the use of autochthonous LAB strains in starter and adjunct cultures for producing dairy products with 'particular geographic indication' status. Such strains should not produce BA; the present results show that BA-production capacity should be checked by (U)HPLC and PCR.

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Section: Resultsmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Genetic and functional analysis of biogenic amine production capacity among starter and non-starter lactic acid bacteria isolated from artisanal cheeses

Ladero

Martín

Redruello

et al. 2015

Eur Food Res Technol

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“…A 100% correlation between the presence of tdc gene and tyramine production has been demonstrated, as reported by Bhardwaj et al . (), Kučerová et al . () and Kalhotka et al .…”

Section: Discussionmentioning

confidence: 96%

Safety Assessment of Enterococcus faecium and Enterococcus faecalis Strains Isolated from Turkish Tulum Cheese

Inoğlu

Tuncer

2013

Journal of Food Safety

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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.

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“…In the strains with the strongest decarboxylase activity, the presence of tdc gene was confirmed. In another study (Bhardwaj et al 2009), the tdc gene was present in twenty from twenty-eight enterococcal strains. Moreover, the authors observed 100% correlation between the results obtained with selective cultivation, tdc targeted PCR and tyramine quantification by high performance liquid chromatography.…”

Section: Discussionmentioning

confidence: 97%

Decarboxylase activity test of the genus Enterococcus isolated from goat milk and cheese

et al. 2012

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Biogenic amines are aliphatic, aromatic or heterocyclic alkalic substances with a biological impact on live organisms. They may cause serious problems to sensitive persons in combination with some medicaments or in case of higher intake. They are present in non-fermented food, usually coming from contaminating microflora, and especially in fermented food where biogenic amines might be produced by microbiota used for procedure. The genus Enterococcus spp. can occur in cheese because their resistance to pasteurizing temperatures is much higher compared to other mesophilic microorganisms. Previous studies have targeted the occurrence and problems of enterococci isolated from cow and sheep milk. The aim of this study was to detect decarboxylase activity of enterococci isolated from goat milk and cheese and to see how the particular temperatures involve decarboxylase activity using a rapid and inexpensive screening method. In this study, bacteria Enterococcus faecium, E. mundtii, E. durans were isolated from 9 samples of goat milk and cheeses. Colonies of bacteria were inoculated on diagnostic medium fortified with amino acids (lysine, arginine, phenylalanine, histidine, tyrosine and tryptophan) and acidity indicator. Changes in colour detected decarboxylase activity of enterococci. The only positive reactions were determined in samples containing arginine and tyrosine. Cultivation of bacteria was confirmed by PCR. All of the tested microorganisms showed significant activity of tyrosindecarboxylase and arginindecarboxylase which was regulated by temperature and influenced by duration of cultivation. The test of decarboxylase activity using colour changes is suitable for a relatively rapid and inexpensive detection of microorganisms that are able to produce biogenic amines.

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Tyramine-producing enterococci are equally detected on tyramine production medium, by quantification of tyramine by HPLC, or bytdcgene-targeted PCR

Cited by 7 publications

References 28 publications

Genetic and functional analysis of biogenic amine production capacity among starter and non-starter lactic acid bacteria isolated from artisanal cheeses

Genetic and functional analysis of biogenic amine production capacity among starter and non-starter lactic acid bacteria isolated from artisanal cheeses

Safety Assessment of Enterococcus faecium and Enterococcus faecalis Strains Isolated from Turkish Tulum Cheese

Decarboxylase activity test of the genus Enterococcus isolated from goat milk and cheese

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