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Antibiotic susceptibility, antibacterial activity and characterisation of Enterococcus faecium strains isolated from breast milk

View Article: PubMed Central - PubMed

ABSTRACT

Enterococci, which have useful biotechnological applications, produce bacteriocins, including those that exert anti-Listerial activity. The present study aimed to determine the antibiotic susceptibility patterns and antimicrobial activity of Enterococcus faecium strains isolated from human breast milk. The strains were identified using carbohydrate fermentation tests and ribotyping. Subsequently, the antibacterial activity of the isolates was investigated, and the quantities of lactic acid and hydrogen peroxide produced, and the proteolytic activity of E. faecium, were determined. In addition, biofilm formation by E. faecium strains was assessed. E. faecium strains exhibited antimicrobial activity against food-borne and clinical bacterial isolates. Furthermore, following 24 h incubation, the tested strains exhibited resistance to a pH range of 2.0–9.5 and tolerance of bile acid, lysozyme activity and phenol. Supernatants of the E. faecium TM13, TM15, TM17 and TM18 strains were shown to be effective against Listeria monocytogenes, and were also resistant to heat. Further studies are required in order to determine whether certain strains of E. faecium may be used for the development of novel antibacterial agents.

No MeSH data available.


Ribotyping profiles of Enterococcus faecium isolates from human breast milk and standard (DUP-6225).
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f1-etm-0-0-3545: Ribotyping profiles of Enterococcus faecium isolates from human breast milk and standard (DUP-6225).

Mentions: A total of 20 isolates were cultured from the breast milk sample, and identified using various phenotypic and genotypic tests. The results of cell morphological analyses, and the growth of the isolates at various temperatures and salinity, are presented in Table I. All isolates were Gram-positive, catalase-negative and oxidase-negative. Sugar fermentation tests were performed using the API ID 32 STREP system. According to the phenotypic tests, the strains were identified as E. faecium, which was confirmed by the automated EcoRI ribotyping results (Fig. 1). EcoRI ribotyping differentiated the isolates into two distinct ribotypes, with similarities ranging from 0.89–0.96. The two distinct ribotypes belonged to two DUP-IDs: DUP-6225, which was classified as Lineage I, and DUP-6227, which was classified as Lineage II.


Antibiotic susceptibility, antibacterial activity and characterisation of Enterococcus faecium strains isolated from breast milk
Ribotyping profiles of Enterococcus faecium isolates from human breast milk and standard (DUP-6225).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4998354&req=5

f1-etm-0-0-3545: Ribotyping profiles of Enterococcus faecium isolates from human breast milk and standard (DUP-6225).
Mentions: A total of 20 isolates were cultured from the breast milk sample, and identified using various phenotypic and genotypic tests. The results of cell morphological analyses, and the growth of the isolates at various temperatures and salinity, are presented in Table I. All isolates were Gram-positive, catalase-negative and oxidase-negative. Sugar fermentation tests were performed using the API ID 32 STREP system. According to the phenotypic tests, the strains were identified as E. faecium, which was confirmed by the automated EcoRI ribotyping results (Fig. 1). EcoRI ribotyping differentiated the isolates into two distinct ribotypes, with similarities ranging from 0.89–0.96. The two distinct ribotypes belonged to two DUP-IDs: DUP-6225, which was classified as Lineage I, and DUP-6227, which was classified as Lineage II.

View Article: PubMed Central - PubMed

ABSTRACT

Enterococci, which have useful biotechnological applications, produce bacteriocins, including those that exert anti-Listerial activity. The present study aimed to determine the antibiotic susceptibility patterns and antimicrobial activity of Enterococcus faecium strains isolated from human breast milk. The strains were identified using carbohydrate fermentation tests and ribotyping. Subsequently, the antibacterial activity of the isolates was investigated, and the quantities of lactic acid and hydrogen peroxide produced, and the proteolytic activity of E. faecium, were determined. In addition, biofilm formation by E. faecium strains was assessed. E. faecium strains exhibited antimicrobial activity against food-borne and clinical bacterial isolates. Furthermore, following 24 h incubation, the tested strains exhibited resistance to a pH range of 2.0–9.5 and tolerance of bile acid, lysozyme activity and phenol. Supernatants of the E. faecium TM13, TM15, TM17 and TM18 strains were shown to be effective against Listeria monocytogenes, and were also resistant to heat. Further studies are required in order to determine whether certain strains of E. faecium may be used for the development of novel antibacterial agents.

No MeSH data available.