Whole-genome sequence of Haemophilus parainfluenzae EL1 isolated from healthy supragingival plaque.

Haemophilus parainfluenzae is a Gram-negative bacterium that colonizes the mouth and the upper respiratory tract. Here, we report the genome sequence of H. parainfluenzae strain EL1 isolated from healthy supragingival plaque. This strain is used as a representative commensal of the oral microbiota.

Mechanisms underlying interactions between two abundant oral commensal bacteria.

Complex polymicrobial biofilm communities are abundant in nature particularly in the human oral cavity where their composition and fitness can affect health. While the study of these communities during disease is essential and prevalent, little is known about interactions within the healthy plaque community. Here we describe interactions between two of the most abundant species in this healthy microbiome, Haemophilus parainfluenzae and Streptococcus mitis. We discovered that H. parainfluenzae typically exists adjacent to mitis group streptococci in vivo with which it is also positively correlated based on microbiome data. By comparing in vitro coculture data to ex vivo microscopy we revealed that this co-occurrence is density dependent and further influenced by H2O2 production. We discovered that H. parainfluenzae utilizes a more redundant, multifactorial response to H2O2 than related microorganisms and that this system's integrity enhances streptococcal fitness. Our results indicate that mitis group streptococci are likely the in vivo source of NAD for H. parainfluenzae and also evoke patterns of carbon utilization in vitro for H. parainfluenzae similar to those observed in vivo. Our findings describe mechanistic interactions between two of the most abundant and prevalent members of healthy supragingival plaque that contribute to their in vivo survival.

Impaired host response and the presence of Acinetobacter baumannii in the serum microbiome of type-II diabetic patients.

Type II diabetes (T2D) affects over 10% of the US population and is a growing disease worldwide that manifests with numerous comorbidities and defects in inflammation. This dysbiotic host response allows for infection of the host by numerous microorganisms. In the course of T2D disease, individuals can develop chronic infections including foot ulcers and periodontitis, which lead to further complications and opportunistic infections in multiple body sites. In this study, we investigated the serum of healthy subjects and patients with T2D with (T2DP) or without periodontitis for both microbiome signatures in addition to cytokine profiles. Surprisingly, we detected the presence of Acinetobacter baumanii in the serum of 23% individuals with T2D/T2DP tested. In T2DP, IL-1ß, TNF-α, MCP-1, IL-6, IL-8, and IFN-γ were significantly elevated in ABC-positive subjects. As an emerging pathogen, A. baumanii infection represents a risk for impaired inflammation and the development of comorbidities in subjects with T2D.