Akwaton, polyhexamethylene-guanidine hydrochloride-based sporicidal disinfectant: a novel tool to fight bacterial spores and nosocomial infections

Abstract

Bacterial spores are of continuing interest to the food and medical industries. In efforts to eliminate bacterial spore contamination, a number of sporicidal agents have been developed. Most of these compounds must be used carefully in very specific circumstances as they are toxic to humans. The sporicidal activity of Akwaton, a polyhexamethylene-guanidine hydrochloride (PHMGH)-based disinfectant, was tested against Bacillus subtilis spores. PHMGH is a colourless, odourless, non-corrosive and non-irritating antimicrobial biocide of the guanidine family. Spores suspended in distilled water and spores placed on solid surfaces (stainless steel and glass) were used to determine the log 10 reduction after exposure to varying concentrations of Akwaton. The minimum sporostatic concentration, the minimum sporicidal concentration and the time required for sporicidal activity corresponded to 0.06% (w/v), 0.08 % (w/v) and 8.5 min, respectively. Disinfectant concentrations of 0.24 % (w/v) and 0.44 % (w/v) killed all spores suspended in distilled water within 3 min and 90 s, respectively. The sporicidal activity against suspended spores was linearly dependent with respect to the concentration of PHMGH and contact time (y 3 min 540x"1.6 and y 90 s 520x"0.8 thus y 3 min 52y 90 s ). Spores placed on surfaces were more resistant to the effect of the disinfectant and the positive linear correlation between the sporicidal activity and concentration was not observed. The concentration required to kill all spores placed on a surface (stainless steel or glass) corresponded to 0.52 % (w/v) for 90 s of contact and 0.36 % (w/v) for 3 min. This study demonstrated that PHMGH is an effective sporicidal disinfectant with great potential for use in hospitals, laboratories, food industries and households.

In Vitro Assessment of the Toxic Effects of an AKWATON based-disinfectant on Human Tissues

“…Oulé et al [19] have clearly demonstrated its bactericidal activity against Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella choleraesuis, meticillin-resistant S. aureus (MRSA) and E. coli; its sporicidal activity against Bacillus subtilis spores [20] and its fungicidal activity against Trichophyton mentagrophytes [4]. In addition to its microbicidal properties, it has been demonstrated that AKWATON was much less toxic to rat cells than well-known disinfectants currently on the market.…”

“…In addition, cell cultures and the different tests carried out by Oulé et al [20], showed that the new AKWATON-based disinfectant killed fewer animal cells than the commercial disinfectants, sparing 80% of rat pancreatic (C2C12) cells and 65% of muscle RnM5F cells, whilst some of the well-known disinfectants currently on the market killed 85-100% of those cells.…”

“…AKWATON is a polyhexamethylene guanidine hydrochloride (PHMGH) based formulation of a novel disinfectant. PHMGH, a member of the guanidine family, is a polymer with bactericidal, fungicidal, and sporicidal, properties that has been demonstrated to work at low concentrations with short contact times [19][20][21]. The bactericidal activity against E. coli and meticillin-resistant Staphylococcus aureus (MRSA) and the mode of action of PHMGH have been clearly demonstrated by Oulé et al [20].…”

“…Their results showed that no matter what type of water (distilled, tap and hard water) was used to make dilutions, AKWATON killed MRSA and E. coli respectively at a low concentration of 0.04% and 0.005% within 1.5 minutes [19]. These authors also demonstrated that the minimum sporostatic concentration, the minimum sporicidal concentration and the time required for sporicidal activity corresponded to 0.06% (w/v), 0.08% (w/v) and 8.5 minutes, respectively [19]; and that the minimum inhibitory concentration, the minimum fungicidal concentration (MFC) and time required for the fungicidal activity of AKWATON at the MFC were 0.025% (w/v), 0.045% (w/v) and 2.5 min, respectively Oulé et al [20].…”

“…PHMGH, a member of the guanidine family, is a polymer with bactericidal, fungicidal, and sporicidal, properties that has been demonstrated to work at low concentrations with short contact times [19][20][21]. The bactericidal activity against E. coli and meticillin-resistant Staphylococcus aureus (MRSA) and the mode of action of PHMGH have been clearly demonstrated by Oulé et al [20]. Their results showed that no matter what type of water (distilled, tap and hard water) was used to make dilutions, AKWATON killed MRSA and E. coli respectively at a low concentration of 0.04% and 0.005% within 1.5 minutes [19].…”