Abstract

JURADO-GAMEZ, Henry; MARTINEZ-BENAVIDES, Javier  and  PAZ, Cristian. Characterization of the Fermentation Process and the Inhibition Effect of Lactobacillus lactis in Staphylococcus aureus and Staphylococcus epidermidis. Rev. Med. Vet. [online]. 2015, n.30, pp.15-29. ISSN 0122-9354.

The fermentative process and in vitro inhibition of L. lactis in Staphylococcus aureus and Staphylococcus epidermidis were assessed. The growth of L. lactis at three pH (2.5, 4.5 and 7), bile salts (0.5, 1 and 2 %), bovine bile (1 and 1.2 %) and two temperatures (38 and 45 °C) were evaluated. Peptides and organic acids in supernatant of L. lactis by HPLC were determined. Fermentation kinetics was carried out, evaluating: pH, total sugar, protein and lactic acid. An antibiogram of dicloxacilin, cefepime, penilicin and cefalotin was made. The inhibition of L. lactis and its supernatant were defined in pathogenic strains. The best growth was at a pH of 2.5 (3 x 10¹² UFC/ml); of 1 x 10¹⁰ and 4 x 10⁹ UFC/ml for 0.5 % of bile salts and 1.2 % of bovine bile, respectively; of 3.5 x 10¹³ and 3.4 x 10¹³ UFC/ml for 38 and 45 °C, respectively. The HPLC determined the peptides VAR-TIR-VAR and lactic acid (83.11 %). The fermentation kinetics determined the exponential phase at 14:24 h with a value of 77 x 10¹⁰ UFC/ml, pH values of 4.284, 2.33 mg/ml sugar, 1.44 mg/ml protein and acidity of 0.79 %. It was found that S. aureus and S. epidermidis were sensitive to all antibiotics. The pathogenic bacteria were resistant to the lactic strain, but S. epidermidis was sensitive to the supernatant of L. lactis. The conclusion is that Lactobacillus lactis showed adequate growth capacity, good fermentation parameters and inhibitory effect in strains of S. aureus and S. epidermidis in in vitro conditions.

Keywords : microbial antagonism; growth; Lactobacillus lactis; Staphylococcus aureus; Staphylococcus epidermidis.

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