Susceptibility of Campylobacter jejuni to organic acids and monoacylglycerols

Abstract

Organic acids can be used as feed supplements or for treatment of poultry carcasses in processing plants. The antimicrobial activity of nineteen organic acids and two monoacylglycerols in cultures of Campylobacter jejuni CCM 6214(T) (ATCC 33560) was determined using a SYBR Green-based real-time PCR assay. The IC(50) was a concentration at which only 50 % of a bacteria specific DNA sequence was amplified. Caprylic, capric and lauric acids were the most efficient antimicrobials among the compounds tested (IC(50) < or = 0.1 mg/mL). In a weakly acidic environment (pH 5.5), the antimicrobial activity was more pronounced than at pH 6.5. At pH 5.5, oleic and fumaric acid also had clear antimicrobial activity, as did monocaprylin. The antimicrobial activity of acetic, butyric, stearic and succinic acid was low. In cells treated with fumaric acid, the potential of potassium and tetraphenylphosphonium ion-selective electrodes changed, indicating an increase in cytoplasmic and outer membrane permeability, respectively. No changes in membrane permeability were observed in cells treated with capric acid or monocaprin. Transmission electron microscopy revealed separation of the inner and outer membrane in cells treated with capric and fumaric acid, as well as cytoplasmic disorganization in cells exposed to capric acid.

Antimicrobial activities of medium-chain fatty acids and monoacylglycerols on Cronobacter sakazakii DBM 3157^T and Cronobacter malonaticus DBM

“…Salmonella species were susceptible to caproic acid (Van Immerseel et al 2004) and caprylic acid (Skřivanová et al 2004). Thormar et al (2006) found that capric acid and monocaprin were more efficient against Campylobacter jejuni as compared with caprylic acid and monocaprylin, this observation having been confirmed by Molatová et al (2010). Depending on the monocaprylin concentrations and the temperatures examined, increasing temperature enhanced the bactericidal activity of monocaprylin, which can be partially explained by an increase in solubility.…”

“…Reports on the effects of capric acid, lauric acid, and monocaprin on Cronobacter, which is a Gram-negative bacterium and thus less susceptible to antimicrobials relative to Gram-positive bacteria, are absent from the current literature. In contrast, reports exist on the antimicrobial action of MCFAs and monoacylglycerols against several other Gram-negative food-borne pathogens that include e. coli (Hassinen et al 1951;Petschow et al 1998;Marounek et al 2003), Salmonella (Skřivanová et al 2004;Van Immerseel et al 2004) and Campylobacter jejuni (Thormar et al Molatová et al 2010). The antimicrobial actions of MCFAs and monoacylglycerols in these studies were variable, and strain-to-strain variability of the susceptibility of different bacteria to these antimicrobials was apparent.…”

“…In experiments with bacteria belonging to the enterobacteriaceae, caprylic acid was more active against escherichia coli and Salmonella than fatty acids with shorter or longer chain lengths (Marounek et al 2003;Skřivanová et al 2004). Both caprylic acid and its monoglyceride monocaprylin were active against Campylobacter jejuni (Molatová et al 2010). In the case of Cronobacter sp., Nair et al (2004) reported that monocaprylin displays a significant inhibitory activity against C. sakazakii strains that were isolated from infant formulae or processing plants.…”

Susceptibility of Escherichia coli and Clostridium perfringens to sucrose monoesters of capric and lauric acid

“…The suspension was incubated for another 3 min or until the values did not rise anymore. Values were automatically recorded every 3 s. The detailed description of this technique has already been used and published (Ohmizo et al 2004;Molatova et al 2010).…”

Fumaric acid, an antibacterial component of Aloe vera L.

“…Molatová et al (2010) demonstrated that fumaric acid had clear antimicrobial activity to Campylobacter jejun. Kim et al (2001) reported that fumaric acid isolated from Camellia japonica L. produced an inhibitory activity against the pathogens Salmonella typhimurium, E. coli, Listeria monocytogenes and S. aureus.…”