Susceptibility of the rabbit enteropathogenic strain Escherichia coli C6 (O128 serogroup) to C6-C14 fatty acids, oleic, citric, lactic and fumaric acid at 5 mg/mL was determined by the plating technique in the near-neutral pH region (pH approximately 6.5), and in a weakly acid and acid environment (pH 5.4 +/- 0.1 and 2.2-2.5, respectively). In the near-neutral pH region caproic and caprylic acid reduced the concentration of viable cells by 3 and 6 orders, respectively. At lower pH the bactericidal effect of caproic acid remained similar, but caprylic acid decreased the concentration of viable cells to < 100/mL. The bactericidal activity of capric acid was low at pH 6.5 but increased at pH 5.3. High environmental acidity was intrinsically bactericidal and at very low pH the effects of fatty acids were thus less pronounced. Citric acid reduced the counts of viable cells to 1/10. Antimicrobial activity of other acids examined was marginal or absent. Medium-chain fatty acids, caprylic and, to a lesser extent, also caproic and capric acid were better antimicrobials than other organic acids examined; the antimicrobial activity of fatty acids toward the C6 strain was pH-dependent. Beneficial effects of citric, lactic and fumaric acid reported by animal nutritionists are thus probably related to factors other than their direct antimicrobial action.

• MeSH
• antibakteriální látky farmakologie   MeSH
• Escherichia coli účinky léků   růst a vývoj   MeSH
• infekce vyvolané Escherichia coli mikrobiologie   veterinární   MeSH
• kapryláty farmakologie   MeSH
• koncentrace vodíkových iontů MeSH
• králíci MeSH
• kyselina citronová farmakologie   MeSH
• kyseliny karboxylové farmakologie   MeSH
• mastné kyseliny farmakologie   MeSH
• mikrobiální testy citlivosti MeSH
• organické látky farmakologie   MeSH
• počet mikrobiálních kolonií MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky MeSH
• kapryláty MeSH
• kyselina citronová MeSH
• kyseliny karboxylové MeSH
• mastné kyseliny MeSH
• octanoic acid MeSH Prohlížeč
• organické látky MeSH

The addition of 100-300 mmol/L of acetic, propionic, butyric or lactic acids (short-chain acids), or of acetic, propionic, and butyric acids (volatile fatty acids, VFA) mixtures increased the degradation of carboxymethyl cellulose (CMC) by R. albus (7.5 to 46 and 6 to 39 %, respectively). Differences among individual acids were observed at 300 mmol/L whereas VFA mixtures differed at 100 mmol/L. When assayed at the same concentration, CMCase activity was increased less by NaCl than by the short-chain acids, whereas ethylene glycol decreased the activity. Since osmolarity and/or ionic strength changes in the medium cannot completely account for the observed increases of carboxymethylcellulase (CMCase) activity, it is suggested that the anions of short-chain acids produce changes in the reaction media polarity that contribute to the effects observed. Alterations in the media could also bring about conformational changes in CMCase leading to increased rates of reaction and subsequent increases in CMC degradation. Finally, explanations for the observed phenomena based on the direct effect of the compounds tested on the cellulosome complex, its domains, and/or its component enzymes are proposed.

• MeSH
• acetáty farmakologie   MeSH
• bachor mikrobiologie   MeSH
• butyráty farmakologie   MeSH
• celulasa metabolismus   MeSH
• chlorid sodný farmakologie   MeSH
• propionáty farmakologie   MeSH
• Ruminococcus enzymologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• acetáty MeSH
• butyráty MeSH
• carboxymethylcellulase MeSH Prohlížeč
• celulasa MeSH
• chlorid sodný MeSH
• propionáty MeSH

The susceptibility of Salmonella spp. to 15 fatty acids was determined in vitro in cultures grown on glucose. Antimicrobial activity was expressed as IC50 (a concentration at which only 50% of the initial glucose in cultures was utilized). Caprylic acid was the only acid inhibiting glucose utilization. In cultures of S. enteritidis, S. infantis and S. typhimurium, IC50 of caprylic acid ranged from 0.75 to 1.17 mg/mL. A moderate adaptation effect was observed as these values increased 1.5-1.8 times when bacteria were subcultured 10 times in media containing a low concentration of caprylic acid (1/3 IC50). No effect of calcium ions added in excess on antimicrobial activity of caprylic acid was observed. Incubation of salmonellas with caprylic acid (1 mg/mL; 30 min) at pH 5.2-5.3 led to a reduction in the concentration of viable cells below the detection limit; 2-6% of Salmonella cells survived at pH 6.3-6.6.

• MeSH
• antibakteriální látky chemie   farmakologie   MeSH
• časové faktory MeSH
• fyziologická adaptace MeSH
• glukosa metabolismus   MeSH
• kapryláty farmakologie   MeSH
• koncentrace vodíkových iontů MeSH
• mastné kyseliny chemie   farmakologie   MeSH
• mikrobiální testy citlivosti MeSH
• počet mikrobiálních kolonií MeSH
• Salmonella enteritidis účinky léků   růst a vývoj   metabolismus   MeSH
• Salmonella typhimurium účinky léků   růst a vývoj   metabolismus   MeSH
• Salmonella účinky léků   růst a vývoj   metabolismus   MeSH
• tolerance léku MeSH
• vápník farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky MeSH
• glukosa MeSH
• kapryláty MeSH
• mastné kyseliny MeSH
• octanoic acid MeSH Prohlížeč
• vápník MeSH