AUTHOR=Liu Tsunglin , Chen Yen-Chin , Jeng Shuen-Lin , Chang Jui-Jen , Wang Jiu-Yao , Lin Cheng-Han , Tsai Pei-Fang , Ko Nai-Ying , Ko Wen-Chien , Wang Jiun-Ling 

TITLE=Short-term effects of Chlorhexidine mouthwash and Listerine on oral microbiome in hospitalized patients

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=Volume 13 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2023.1056534

DOI=10.3389/fcimb.2023.1056534

ISSN=2235-2988

ABSTRACT=Chlorhexidine (CHX) and essential oil containing mouthwashes like Listerine® maintain oral hygiene via suppressing oral microbes. In hospitalized patients, CHX mouthwash reduces the incidence of ventilator-associated pneumonia, but CHX use had been associated with increased mortality, which might be related to nitrate-reducing bacteria. Currently, no study determines oral bacteria targeted by essential oils mouthwash in hospitalized patients using a metagenomic approach. We recruited 87 hospitalized patients from a previous randomized control study, and assigned them to three mouthwash groups: CHX, Listerine®, and normal saline (control). Before and after gargling the mouthwash twice a day for 5-7 days, oral bacteria were examined using a 16S rDNA approach. Alpha diversities at the genus level decreased significantly only for the CHX and Listerine groups. Only for the two groups, oral microbiota before and after gargling were significantly different, but not clearly distinct. Paired analysis eliminated the substantial individual differences and revealed eight bacterial genera (including Prevotella, Fusobacterium, and Selenomonas) with a decreased relative abundance, while Rothia increased after gargling CHX mouthwash. After gargling Listerine, seven genera (including Parvimonas, Eubacterium, and Selenomonas) showed a decreased relative abundance, and the magnitudes were smaller compared to the CHX group. After gargling CHX, there were respective increased and decreased relative abundance of Rothia and Prevotella. Besides, fewer bacteria targeted by Listerine were reported to be nitrate-reducing compared to CHX mouthwash. In conclusion, short-term gargling of CHX mouthwash and Listerine altered oral microbiota in our hospitalized patients. The bacterial genera targeted by CHX mouthwash and Listerine were largely different and the magnitudes of changes were smaller using Listerine. Functional alterations of gargling CHX and Listerine were also different. These findings can be taken into account for managing oral hygiene of hospitalized patients.