Investigation of action of peroxoacetic acid on lipid component of bacterial spores and contribution to the standardization of efficiency evaluation test

Abstract

The aim of this research was to contribute to a more detailed insight in the action of peroxygen disinfectants based on peroxoacetic acid (PAA), on lipid components of sporogenic forms of microorganisms. Sporogenic forms are recognized to be significantly more resistant in comparison to vegetative forms. Bacillus cereus ATCC 11778 and Bacillus subtilis NCTC 10480 where chosen as referent bacterial sporogenic strains used to investigate the acting mechanism of PAA. After treatment of the above mentioned bacterial strains with PAA, fatty acids have been isolated from untreated and treated spores and consequent changes in the lipid component were analyzed. The obtained methyl-esters of fatty acids (MEFA) were analyzed by gas chromatography/mass spectrometry (GC/MS), using a standard of bacterial MEFA. Results confirmed that after treatment, in Bacillus cereus certain quantitative changes occurred, which included the decrease in quantity of fatty acids with 16 and 17 carbon atoms, i.e. 16:0, 16:1, /so 17:0 and anteiso 17:0. At the same time, in B. Subtilis the significant decrease in quantity of fatty acids with 15 and 17 carbon atoms occurred, i.e. anteiso 15:0 and anteiso 17:0.

Cilj ovog istraživanja je bio da se stekne potpuniji uvid u dejstvo peroksigenih dezinfektanata na bazi peroksosircetne kiseline (u daljem tekstu: PSK) na lipidnu komponentu sporogenih formi mikroorganizama, za koje je poznato da pokazuju veću otpornost od vegetativnih oblika. Bacillus cereus ATCC 11778 i Bacillus subtilis NCTC 10480 su odabrani kao referentni sojevi - bioindikatori, na kojima je ispitivano delovanje PSK (nakon formiranja spora). Nakon tretmana spora pomenutih bakterijskih sojeva sa PSK, izolovane su masne kiseline iz netretiranih i tretiranih spora i analizirane su promene u lipidnoj komponenti. Dobijeni metil-estri masnih kiselina (MEMK) analizirani su pomoću gasne hromatografije i masene spektrometrije (GC/MS) uz poređenje sa standardom bakterijskih MEMK. Dobijeni rezultati su ukazali da je kod B. cereus ATCC 11778 nakon tretmana došlo do kvantitativne promene odnosno smanjenja količine masnih kiselina sa 16 i 17 Catoma, odnosno 16:0,16:1, ante/so 17:0,/so 17:0. Kod B. subtilis NCTC 10480 došlo je do značajnog smanjenja količine masnih kiselina sa 15 i 17 C atoma, odnosno anteiso 15:0 i anteiso 17:0.