Differential oxidative stress tolerance of Streptococcus mutans isolates affects competition in an ecological mixed‐species biofilm model

Abstract

Streptococcus mutans strongly influences the development of pathogenic biofilms associated with dental caries. Our understanding of S. mutans behaviour in biofilms is based on a few well-characterized laboratory strains; however, individual isolates vary widely in genome content and virulence-associated phenotypes, such as biofilm formation and environmental stress sensitivity. Using an ecological biofilm model, we assessed the impact of co-cultivation of several S. mutans isolates with Streptococcus oralis and Actinomyces naeslundii on biofilm composition following exposure to sucrose. The laboratory reference strain S. mutans UA159 and clinical isolates Smu44 (most aciduric), Smu56 (altered biofilm formation) and Smu81 (more sensitive to oxidative stress) were used. Our data revealed S. mutans isolates varied in their ability to compete and become dominant in the biofilm after the addition of sucrose, and this difference correlated with sensitivity to H O produced by S. oralis. Smu81 was particularly sensitive to H O and could not compete with S. oralis in mixed-species biofilm, despite forming robust biofilms on its own. Thus, diminished oxidative stress tolerance in S. mutans isolates can impair their ability to compete in complex biofilms, even in the presence of sucrose, which could influence the progression of a healthy biofilm community to one capable of causing disease.

Amino Sugars Modify Antagonistic Interactions between Commensal Oral Streptococci and Streptococcus mutans

“…In a separate study that focused on the effects of arginine on the antagonistic interactions between oral commensals and S. mutans, it was shown that enormous diversity exists among commensal streptococci, both in their antagonistic capabilities and their susceptibility to S. mutans (48). Clearly, probing the basis for phenotypic variation among commensals and pathogens (49) remains an essential goal in efforts to improve caries risk assessment and intervention.…”

Evaluating Streptococcus mutans Strain Dependent Characteristics in a Polymicrobial Biofilm Community

“…Significant differences were observed, and were not only dependent on the sugars, but also on specific isolates. Liu S.S. et al (2017) revealed S. mutans isolates varied in their ability to compete and become dominant in the biofilm after the addition of sucrose ( Liu Y. et al, 2017 ). Interactions between microorganisms colonizing the oral cavity are consecutive factors affecting the development of biofilm, with interactions occurring between microorganisms resulting in both the acceleration and inhibition of this process ( Wen et al, 2010 ; Redanz et al, 2011 ).…”

A Comparison of Flavorless Electronic Cigarette-Generated Aerosol and Conventional Cigarette Smoke on the Survival and Growth of Common Oral Commensal Streptococci

“…These species are considered commensal early colonizers [20,21,22]. All four species are beneficial to the host oral cavity in the context of their interactions with pathogenic species related both to caries and periodontal disease [23,24,25,26,27,28]. By extension, since oral health and overall general health are directly correlated, any disruption to the bacterial flora within the oral cavity could lead to systemic diseases, especially certain types of cardiovascular disease [29].…”