Inhibition of multidrug‐resistant Staphylococci by sodium chlorate and select nitro‐ and medium chain fatty acid compounds

Abstract

Aims Determine the antimicrobial effects of 5 μmol ml−1 sodium chlorate, 9 μmol ml−1 nitroethane or 2‐nitropropanol as well as lauric acid, myristic acid and the glycerol ester of lauric acid Lauricidin®, each at 5 mg ml−1, against representative methicillin‐resistant staphylococci, important mastitis‐ and opportunistic dermal‐pathogens of humans and livestock. Methods and Results Three methicillin‐resistant Staphylococcus aureus and two methicillin‐resistant coagulase‐negative staphylococci were cultured at 39°C in 5 μmol ml−1 nitrate‐supplemented half‐strength Brain Heart Infusion broth treated without or with the potential inhibitors. Results revealed that 2‐nitropropanol was the most potent and persistent of all compounds tested, achieving 58–99% decreases in mean specific growth rates and maximum optical densities when compared with untreated controls. Growth inhibition did not persist by cultures treated solely with chlorate or nitroethane, with adaptation occurring by different mechanisms after 7 h. Adaptation did not occur in cultures co‐treated with nitroethane and chlorate. The medium chain fatty acid compounds had modest effects on all the staphylococci tested except the coagulase‐negative Staphylococcus epidermidis strain NKR1. Conclusions The antimicrobial activity of nitrocompounds, chlorate and medium chain fatty acid compounds against different methicillin‐resistant staphylococci varied in potency. Significance and Impact of the Study Results suggest that differential antimicrobial activities exhibited by mechanistically dissimilar inhibitors against methicillin‐resistant staphylococci may yield potential opportunities to combine the treatments to overcome their individual limitations and broaden their activity against other mastitis and dermal pathogens.

Innovative Treatments Enhancing the Functionality of Gut Microbiota to Improve Quality and Microbiological Safety of Foods of Animal Origin

“…Nitrocompounds, with a structural formula depicted as R-NO 2 , are organic compounds that contain one or more functional nitro groups within their aromatic ring or aliphatic chain and are classified as such based on the presence of various alkyls (Madaj et al 2016, Parry et al 2011, Smith & Anderson 2013, Zhang et al 2018. A variety of different nitrocompounds have been investigated via in vivo and in vitro studies over the years, reporting that nitrocompounds exhibit antimicrobial or bactericidal activities against foodborne pathogens (Adhikari et al 2017, Anderson et al 2007, Božić et al 2019, Dimitrijevic et al 2006, Jung et al 2004) and an inhibitory activity on the formation of indole and 3-methylindole (skatole), which are odor pollutants in livestock waste and major causes of boar taint in swine (Beier et al 2009). Nitrocompounds can be used as an intervention treatment to control foodborne pathogens at the preharvest level, aiming for microbiologically safer animal-derived foods for human consumption.…”

Assessment of Potential Anti-Methanogenic and Antimicrobial Activity of Ethyl Nitroacetate, α-Lipoic Acid, Taurine and L-Cysteinesulfinic Acid In Vitro

“…Certain oxidized nitro-containing compounds such as nitrate as well as some short-chain nitroalkanes and oxy-nitrocompounds are potent inhibitors of ruminal methanogenesis, a digestive inefficiency that can result in the loss of up to 15% of dietary intake for forage-fed cattle and 2 to 4% for concentrate fed cattle [ 1 , 2 ]. Some of these nitroalkanes have also been reported to inhibit the growth of important foodborne pathogens such as enterohemorrhagic Escherichia coli , Campylobacter species jejuni and coli , Salmonella enterica serovar Typhimurium and Staphylococcus species aureus, epidermidis and hyicus [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ].…”

Proteomic Investigation over the Antimicrobial Photodynamic Therapy Mediated by Rose Bengal Against Staphylococcus aureus

“…Moreover, staphylococcal food poisoning is considered one of the world's leading causes of outbreaks related to food consumption (3). Thus, the concern for this microorganism increased due to the emergence of staphylococcal strains with antimicrobial resistance in health care systems and the food industry (4,5).…”