Correlation of Aggregatibacter actinomycetemcomitans Detection with Clinical/Immunoinflammatory Profile of Localized Aggressive Periodontitis Using a 16S rRNA Microarray Method: A Cross-Sectional Study

Patricia F Gonçalves,Luciana M Shaddox,Vanja Klepac-Ceraj,Hong Huang,Ikramuddin Aukhil,Bruce J Paster,Shannon M Wallet

doi:10.1371/journal.pone.0085066

Abstract

ObjectiveThe objective of this study was to determine whether the detection of Aggregatibacter actinomycetemcomitans (Aa) correlates with the clinical and immunoinflammatory profile of Localized Aggressive Periodontitis (LAP), as determined by by 16S rRNA gene-based microarray. Subjects and MethodsSubgingival plaque samples from the deepest diseased site of 30 LAP patients [PD ≥ 5 mm, BoP and bone loss] were analyzed by 16S rRNA gene-based microarrays. Gingival crevicular fluid (GCF) samples were analyzed for 14 cyto/chemokines. Peripheral blood was obtained and stimulated in vitro with P.gingivalis and E.coli to evaluate inflammatory response profiles. Plasma lipopolysaccharide (LPS) levels were also measured. Results Aa was detected in 56% of LAP patients and was shown to be an indicator for different bacterial community structures (p<0.01). Elevated levels of pro-inflammatory cyto/chemokines were detected in LPS-stimulated blood samples in both Aa-detected and Aa-non-detected groups (p>0.05). Clinical parameters and serum LPS levels were similar between groups. However, Aa-non-detected GCF contained higher concentration of IL-8 than Aa-detected sites (p<0.05). TNFα and IL1β were elevated upon E.coli LPS stimulation of peripheral blood cells derived from patients with Aa-detected sites. ConclusionsOur findings demonstrate that the detection of Aa in LAP affected sites, did not correlate with clinical severity of the disease at the time of sampling in this cross-sectional study, although it did associate with lower local levels of IL-8, a different subgingival bacterial profile and elevated LPS-induced levels of TNFα and IL1β.

Highlights

Aggregatibacter actinomycetemcomitans (Aa) is a Gramnegative bacterium that colonizes the oral cavity of one third or more of the population aged up to 18 years [1]
Clinical and microbiologic characterization Human Oral Microbe Identification Microarrays (HOMIM) resulted in 189 probes identifying at least 137 different bacterial taxa in diseased sites of localized presentation of the disease (LAP)
Clinical parameters and demographics were similar between individuals with Aa-detected or Aa-nondetected sites, as determined by HOMIM (Table 1)

Summary

Introduction

Aggregatibacter actinomycetemcomitans (Aa) is a Gramnegative bacterium that colonizes the oral cavity of one third or more of the population aged up to 18 years [1]. It has been highly implicated as the causative agent of aggressive periodontitis (AgP), a group of less frequent, often severe, rapidly progressive forms of periodontitis, with a more localized presentation of the disease (LAP) [2,3,4]. Little is known regarding the impact of Aa’s presence on LAP disease presentation (clinical parameters and bacterial colonization) or the accompanying inflammatory response (regulation and local presentation)

Methods

Results

Conclusion