Lack of efficient killing of purified dormant spores of Bacillales and Clostridiales species by glycerol monolaurate in a non-aqueous gel.
Anti-Bacterial Agents
/ pharmacology
Bacillales
/ drug effects
Bacillus cereus
/ drug effects
Bacillus megaterium
/ drug effects
Bacillus subtilis
/ drug effects
Clostridiales
/ drug effects
Clostridioides difficile
/ drug effects
Food Microbiology
Gels
/ pharmacology
Laurates
/ pharmacology
Monoglycerides
/ pharmacology
Spores, Bacterial
/ drug effects
Bacillus
bacterial spores
biocides
disinfection
sterilization
Journal
Letters in applied microbiology
ISSN: 1472-765X
Titre abrégé: Lett Appl Microbiol
Pays: England
ID NLM: 8510094
Informations de publication
Date de publication:
Jun 2020
Jun 2020
Historique:
received:
31
12
2019
revised:
29
02
2020
accepted:
02
03
2020
pubmed:
7
3
2020
medline:
23
7
2020
entrez:
6
3
2020
Statut:
ppublish
Résumé
Inactivation of Bacillales and Clostridiales spores is of interest, since some cause food spoilage and human diseases. A recent publication (mSphere 3: e00597-1, 2018) reported that glycerol monolaurate (GML) in a non-aqueous gel (GMLg) effectively killed spores of Bacillus subtilis, Bacillus cereus and Clostridioides difficile, and Bacillus anthracis spores to a lesser extent. We now show that (i) the B. subtilis spores prepared as in the prior work were impure; (ii) if spore viability was measured by diluting spores 1/10 in GMLg, serially diluting incubations 10-fold and spotting aliquots on recovery plates, there was no colony formation from the 1/10 to 1/1000 dilutions due to GMLg carryover, although thorough ethanol washes of incubated spores eliminated this problem and (iii) GMLg did not kill highly purified spores of B. subtilis, B. cereus, Bacillus megaterium and C. difficile in 3-20 h in the conditions used in the recent publication. GMLg also gave no killing of crude B. subtilis spores prepared as in the recent publication in 5 h but gave ~1·5 log killing at 24 h. Thus, GMLg does not appear to be an effective sporicide, although the gel likely inhibits spore germination and could kill spores somewhat upon long incubations. SIGNIFICANCE AND IMPACT OF THE STUDY: Given potential deleterious effects of spores of Bacillales and Clostridiales, there is an ongoing interest in new ways of spore killing. A recent paper (mSphere 3: e00597-1, 2018) reported that glycerol monolaurate (GML) in a non-aqueous gel (GMLg) effectively killed spores of many species. We now find that (i) the Bacillus subtilis spores prepared as in the previous report were impure and (ii) GMLg gave no killing of purified spores of Bacillales and Clostridiales species in ≤5 h under the published conditions. Thus, GMLg is not an effective sporicide, though may prevent spore germination or kill germinated spores.
Substances chimiques
Anti-Bacterial Agents
0
Gels
0
Laurates
0
Monoglycerides
0
monolaurin
27215-38-9
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
407-412Informations de copyright
© 2020 The Society for Applied Microbiology.
Références
Chaiba, A., Ababouch, L.H. and Busta, F.F. (1996a) Inhibition of bacterial spores and vegetative cells by glycerides. J Food Prot 59, 716-722.
Chaiba, A., Ababouch, L.H. and Busta, F.F. (1996b) Inhibition by monoglycerides of 1-alanine-triggered Bacillus cereus and Clostridium botulinum spore germination and outgrowth. J Food Prot 59, 832-837.
Clements, M.O. and Moir, A. (1998) Role of the gerI operon of Bacillus cereus 569 in the response of spores to germinants. J Bacteriol 180, 6929-6935.
Coleman, W.H., Zhang, P., Li, Y.-Q. and Setlow, P. (2010) Mechanism of killing of spores of Bacillus cereus and Bacillus megaterium by wet heat. Lett Appl Microbiol 50, 507-514.
Cortezzo, D.E., Koziol-Dube, K., Setlow, B. and Setlow, P. (2004) Treatment with oxidizing agents damages the inner membrane of spores of Bacillus subtilis and sensitizes the spores to subsequent stress. J Appl Microbiol 97, 838-852.
Cowan, A.E., Olivastro, E.M., Koppel, D.E., Loshon, C.A., Setlow, B. and Setlow, P. (2004) Lipids in the inner membrane of dormant spores of Bacillus species are largely immobile. Proc Natl Acad USA 101, 7733-7738.
Dong, W., Green, J., Korza, G. and Setlow, P. (2019) Killing of spores of Bacillus species by cetyltrimethylammonium bromide (CTAB). J Appl Microbiol 126, 1391-1401.
Donnelly, M.L., Fimlaid, K.A. and Shen, A. (2016) Characterization of Clostridium difficile spores lacking either SpoVAC or dipicolinic acid synthetase. J Bacteriol 198, 1694-1707.
Lopes, L.Q., Santos, C.G., de Almeida Vaucher, R., Gende, L., Raffin, R.P. and Santos, R.C. (2016) Evaluation of antimicrobial activity of glycerol monolaurate nanocapsules against American foulbrood disease agent and toxicity on bees. Microb Pathog 97, 183-188.
Mansour, M., Amri, D., Bouttefrouy, A., Linder, M. and Milliere, J.B. (1999) Inhibition of Bacillus licheniformis spore growth in milk by nisin, monolaurin, and pH combinations. J Appl Microbiol 86, 311-324.
Nicholson, W.L. and Setlow, P. (1990) Sporulation, germination and outgrowth. In Molecular Biological Methods for Bacillus ed. Harwood, C.R. and Cutting, S.M. pp. 391-450. Chichester, UK: John Wiley and Sons.
Paidhungat, M., Setlow, B., Driks, A. and Setlow, P. (2000) Characterization of spores of Bacillus subtilis which lack dipicolinic acid. J Bacteriol 182, 5505-5512.
Rode, L.J. and Foster, J.W. (1961) Germination of bacterial spores with alkyl primary amines. J Bacteriol 81, 768-779.
Schlievert, P.M., Kilgore, S.H., Kaus, G.M., Ho, T.D. and Ellermeier, C.D. (2018) Glycerol monolaurate (GML) and a nonaqueous five-percent GML gel kill Bacillus and Clostridium spores. mSphere 3, e00597-1.
Setlow, P. (2006) Spores of Bacillus subtilis: their resistance to radiation, heat and chemicals. J Appl Microbiol 101, 514-525.
Setlow, P. (2019) Observations on research with spores of Bacillales and Clostridiales species. J Appl Microbiol 126, 348-358.
Setlow, P. and Johnson, E.A. (2019) Spores and their significance. In Food Microbiology, Fundamentals and Frontiers (5th edn) ed. Doyle, M.P., Diez-Gonzalez, F. and Hill, C. pp. 23-64. Washington, DC: ASM Press.
Setlow, B. and Setlow, P. (1996) Role of DNA repair in Bacillus subtilis spore resistance. J Bacteriol 178, 3486-3495.
Shearer, A.E., Dunne, C.P., Sikes, A. and Hoover, D.G. (2000) Bacterial spore inhibition and inactivation in foods by pressure, chemical preservatives, and mild heat. J Food Prot 63, 1503-1510.