Minimum Inhibition Concentration of an Antimicrobial Agent Containing Methylisothiazolinone Used in Leather Industry Against Reference Strains

In leather industry soaking process is applied to salted hides and skins in order to rehydrate, to soften, to remove the salt, blood, dung, dirt and microorganisms. The soaking process is a favorable environment for bacterial growth, and during this process significant damage occurs on the hides and skins. It is known that soaked hides/skins contain Gram-positive and Gram-negative bacteria, which can adversely affect hide/skin quality even though they are treated with antimicrobial agents. Insufficient and random use of antimicrobial agents is inadequate in controlling the numbers of these bacteria, and excessive use of them also leads to the emergence of antimicrobial-resistant bacteria. The choice of appropriate antimicrobial agent is very important in preventing damage caused by bacteria found on the hides. Therefore, application of methylisothiazolinone-containing antimicrobial agent used in the leather industry against reference bacterial strains and investigation of the minimum inhibitor concentration will provide important information on the effectiveness of this antimicrobial agent on bacteria that may be harmful to hides in leather processing. In the present study, the eighteen different concentration of antimicrobial agent containing methylisothiazolinone were applied against Gram-negative (Pseudomonas aeruginosa ATCC27853, Escherichia coli ATCC25922) and Gram-positive (Staphylococcus epidermidis ATCC12228, Staphylococcus aureus ATCC29213, Micrococcus luteus ATCC9341, Enterococcus faecalis ATCC29212, Bacillus cereus ATCC11778, Bacillus subtilis ATCC6633) reference strains and their mixed culture. The minimum inhibitor concentrations were determined using agar dilution method. The minimum inhibitor concentrations of antimicrobial agent were found as 5000 μg/ml for Pseudomonas aeruginosa ATCC27853, Staphylococcus aureus ATCC29213, Micrococcus luteus ATCC9341, mixed culture of test bacteria; 1250 μg/ml for Escherichia coli ATCC25922; 156 μg/ml for Bacillus cereus ATCC11778; 39 μg/ml for Staphylococcus epidermidis ATCC12228 and Enterococcus faecalis ATCC29212; and 9.76 μg/ml for Bacillus subtilis ATCC6633. As a result, it was determined that the tested antimicrobial agent inhibited the growth of eight different reference strains and their mixed culture, and that spectrum of action was broad