Inhibitory effect of mouthwashes on Lactobacilus casei growth

Abstract

This study assessed the inhibitory effect of commercially available mouth rinses on the growth of Lactobacillus casei (ATCC 7469). An inductive approach was adopted with a comparative procedure and the technique of direct observation in the laboratory. The sample consisted of six products (Plax ®, Listerine ®, Cepacol ®, Oral B ®, Sanifill ® and Periogard ®) which were analyzed to measure their Minimum Inhibitory Concentration (MIC) on Blood Agar solid culture medium. Serial dilutions of the mouthwash were carried out, from the commercially available solution, resulting in seven concentrations (1:0 to 1:32). A quantity of 50?L of each solution and their respective dilutions were inserted in wells (6 mm) made in the culture medium. The plates were incubated in a bacteriological incubator at 37 ° C for 24 hours. The halos of growth inhibition were measured and the MIC was considered to be the last concentration at which formation of halos greater than or equal to 10mm were observed. The MIC of the mouthwashes Plax ®, Listerine ®, Cepacol ®, Oral B ®, Sanifill ® and Periogard ® were measured at concentrations of 1:2, 1:8, 1:4, 1:8, 1:16, and 1:32, respectively. It was concluded that the mouthwashes studied presented antimicrobial activity against L. casei, and the largest inhibitory effect was with Periogard ® and Sanifill ®.