Unilateral periocular spasm.

ABSTRACT: Hemifacial spasm is an uncontrollable, recurrent facial muscular contraction that typically occurs on one side of the face, cannot be suppressed, and can last the entire day and during sleep. The most common underlying cause of facial nerve compression is an enlarged or abnormal tracking blood vessel at the brainstem level. Clinical diagnoses are frequently based on a patient's medical history and physical examination. Before deciding on a course of action, however, an electromyogram and MRI are performed to determine the underlying cause. Due to its high effectiveness (success rates of 85% to 95%) and low frequency of adverse reactions, botulinum toxin is the preferred therapy for hemifacial spasm and can provide transient symptomatic alleviation. Surgical microvascular decompression is a therapeutic approach that targets the underlying cause of this condition and has an average success rate of 85%.

Smoking-induced subgingival dysbiosis precedes clinical signs of periodontal disease.

Smoking accelerates periodontal disease and alters the subgingival microbiome. However, the relationship between smoking-associated subgingival dysbiosis and progression of periodontal disease is not well understood. Here, we sampled 233 subgingival sites longitudinally from 8 smokers and 9 non-smokers over 6-12 months, analyzing 804 subgingival plaque samples using 16 rRNA sequencing. At equal probing depths, the microbial richness and diversity of the subgingival microbiome was higher in smokers compared to non-smokers, but these differences decreased as probing depths increased. The overall subgingival microbiome of smokers differed significantly from non-smokers at equal probing depths, which was characterized by colonization of novel minority microbes and a shift in abundant members of the microbiome to resemble periodontally diseased communities enriched with pathogenic bacteria. Temporal analysis showed that microbiome in shallow sites were less stable than deeper sites, but temporal stability of the microbiome was not significantly affected by smoking status or scaling and root planing. We identified 7 taxa-Olsenella sp., Streptococcus cristatus, Streptococcus pneumoniae, Streptococcus parasanguinis, Prevotella sp., Alloprevotella sp., and a Bacteroidales sp. that were significantly associated with progression of periodontal disease. Taken together, these results suggest that subgingival dysbiosis in smokers precedes clinical signs of periodontal disease, and support the hypothesis that smoking accelerates subgingival dysbiosis to facilitate periodontal disease progression.

Stability of healthy subgingival microbiome across space and time.

The subgingival microbiome is one of the most stable microbial ecosystems in the human body. Alterations in the subgingival microbiome have been associated with periodontal disease, but their variations over time and between different subgingival sites in periodontally healthy individuals have not been well described. We performed extensive, longitudinal sampling of the subgingival microbiome from five periodontally healthy individuals to define baseline spatial and temporal variations. A total of 251 subgingival samples from 5 subjects were collected over 6-12 months and deep sequenced. The overall microbial diversity and composition differed significantly between individuals. Within each individual, we observed considerable differences in microbiome composition between different subgingival sites. However, for a given site, the microbiome was remarkably stable over time, and this stability was associated with increased microbial diversity but was inversely correlated with the enrichment of putative periodontal pathogens. In contrast to microbiome composition, the predicted functional metagenome was similar across space and time, suggesting that periodontal health is associated with shared gene functions encoded by different microbiome consortia that are individualized. To our knowledge, this is one of the most detailed longitudinal analysis of the healthy subgingival microbiome to date that examined the longitudinal variability of different subgingival sites within individuals. These results suggest that a single measurement of the healthy subgingival microbiome at a given site can provide long term information of the microbial composition and functional potential, but sampling of each site is necessary to define the composition and community structure at individual subgingival sites.

The subgingival microbiome in patients with established rheumatoid arthritis.

OBJECTIVES: To profile and compare the subgingival microbiome of RA patients with OA controls. METHODS: RA (n = 260) and OA (n = 296) patients underwent full-mouth examination and subgingival samples were collected. Bacterial DNA was profiled using 16 S rRNA Illumina sequencing. Following data filtering and normalization, hierarchical clustering analysis was used to group samples. Multivariable regression was used to examine associations of patient factors with membership in the two largest clusters. Differential abundance between RA and OA was examined using voom method and linear modelling with empirical Bayes moderation (Linear Models for Microarray Analysis, limma), accounting for the effects of periodontitis, race, marital status and smoking. RESULTS: Alpha diversity indices were similar in RA and OA after accounting for periodontitis. After filtering, 286 taxa were available for analysis. Samples grouped into one of seven clusters with membership sizes of 324, 223, 3, 2, 2, 1 and 1 patients, respectively. RA-OA status was not associated with cluster membership. Factors associated with cluster 1 (vs 2) membership included periodontitis, smoking, marital status and Caucasian race. Accounting for periodontitis, 10 taxa (3.5% of those examined) were in lower abundance in RA than OA. There were no associations between lower abundance taxa or other select taxa examined with RA autoantibody concentrations. CONCLUSION: Leveraging data from a large case-control study and accounting for multiple factors known to influence oral health status, results from this study failed to identify a subgingival microbial fingerprint that could reliably discriminate RA from OA patients.

Status Report from the Scientific Panel on Antibiotic Use in Dermatology of the American Acne and Rosacea Society: Part 1: Antibiotic Prescribing Patterns, Sources of Antibiotic Exposure, Antibiotic Consumption and Emergence of Antibiotic Resistance, Impact of Alterations in Antibiotic Prescribing, and Clinical Sequelae of Antibiotic Use.

Oral and topical antibiotics are commonly prescribed in dermatologie practice, often for noninfectious disorders, such as acne vulgaris and rosacea. Concerns related to antibiotic exposure from both medical and nonmedical sources require that clinicians consider in each case why and how antibiotics are being used and to make appropriate adjustments to limit antibiotic exposure whenever possible. This first article of a three-part series discusses prescribing patterns in dermatology, provides an overview of sources of antibiotic exposure, reviews the relative correlations between the magnitude of antibiotic consumption and emergence of antibiotic resistance patterns, evaluates the impact of alterations in antibiotic prescribing, and discusses the potential relevance and clinical sequelae of antibiotic use, with emphasis on how antibiotics are used in dermatology.

Status Report from the Scientific Panel on Antibiotic Use in Dermatology of the American Acne and Rosacea Society: Part 3: Current Perspectives on Skin and Soft Tissue Infections with Emphasis on Methicillin-resistant Staphylococcus aureus, Commonly Encountered Scenarios when Antibiotic Use May Not Be Needed, and Concluding Remarks on Rational Use of Antibiotics in Dermatology.

In this third article of the three-part series, management of skin and soft tissue infections is reviewed with emphasis on new information on methicillin-resistant Staphylococcus aureus. Due to changes in the evolution of methicillin-resistant Staphylococcus aureus clones, previous distinctions between healthcare-acquired methicillin-resistant Staphylococcus aureus and community-acquired methicillin-resistant Staphylococcus aureus are currently much less clinically relevant. Many nosocomial cases of methicillin-resistant Staphylococcus aureus infection are now caused by community-acquired methicillin-resistant Staphylococcus aureus, with changing patterns of antibiotic susceptibility and resistance. Also reviewed are clinical scenarios where antibiotics may not be needed and suggestions for optimal use of antibiotic therapy for dermatologie conditions, including recommendations on perioperative antibiotic use.

Non-antibacterial tetracycline formulations: host-modulators in the treatment of periodontitis and relevant systemic diseases.

Traditionally, the dental profession has primarily treated periodontitis using a mechanical/surgical, rather than a pharmaceutical, approach. However, based on experiments several decades ago which demonstrated that tetracyclines, unexpectedly, inhibit collagen- and bone-destructive mammalian-derived enzymes (e.g. the collagenases), and through non-antibiotic mechanisms, the concept of host-modulation therapy (HMT) was developed. Accordingly, two drug-development strategies evolved: (i) the development of non-antimicrobial formulations of doxycycline; and (ii) the chemical modification of tetracyclines to eliminate their antibiotic activity but retain (or even enhance) their anti-collagenase properties. Regarding the latter, these chemically modified tetracyclines (CMTs) showed efficacy in vitro, in animal models of periodontal (and relevant systemic) disease, and in preliminary clinical trials on patients with Kaposi's sarcoma (however, at the high doses used, photosensitivity was a significant side-effect). In the first strategy, subantimicrobial-dose doxycycline (SDD) demonstrated safety and efficacy in human clinical trials and was approved by the U S Food and Drug Administration (U S FDA) and in other countries for the treatment of periodontitis (20 mg, twice daily, i.e. once every 12 hours) adjunctive to scaling and root planing, and for chronic inflammatory skin diseases (40-mg sustained-release 'beads'). SDD also showed efficacy in patients with systemic diseases relevant to periodontitis, including diabetes mellitus and arthritis, and in postmenopausal women with local and systemic bone loss. Importantly, long-term administration of SDD, of up to 2 years, in clinical trials did not produce antibiotic side-effects. SDD (and in the future, new HMTs, such as low-dose CMT-3, resolvins and chemically modified curcumins) may shift the paradigm of periodontal therapy from a predominantly surgical approach to the greater use of medicinal/pharmacologic strategies, ultimately to benefit larger numbers of patients.

Dysbiosis and alterations in predicted functions of the subgingival microbiome in chronic periodontitis.

Chronic periodontitis is an inflammatory disease of the periodontium affecting nearly 65 million adults in the United States. Changes in subgingival microbiota have long been associated with chronic periodontitis. Recent culture-independent molecular studies have revealed the immense richness and complexity of oral microbial communities. However, data sets across studies have not been directly compared, and whether the observed microbial variations are consistent across different studies is not known. Here, we used 16S rRNA sequencing to survey the subgingival microbiota in 25 subjects with chronic periodontal disease and 25 healthy controls and compared our data sets with those of three previously reported microbiome studies. Consistent with data from previous studies, our results demonstrate a significantly altered microbial community structure with decreased heterogeneity in periodontal disease. Comparison with data from three previously reported studies revealed that subgingival microbiota clustered by study. However, differences between periodontal health and disease were larger than the technical variations across studies. Using a prediction score and applying five different distance metrics, we observed two predominant clusters. One cluster was driven by Fusobacterium and Porphyromonas and was associated with clinically apparent periodontitis, and the second cluster was dominated by Rothia and Streptococcus in the majority of healthy sites. The predicted functional capabilities of the periodontitis microbiome were significantly altered. Genes involved in bacterial motility, energy metabolism, and lipopolysaccharide biosynthesis were overrepresented in periodontal disease, whereas genes associated with transporters, the phosphotransferase system, transcription factors, amino acid biosynthesis, and glycolysis/gluconeogenesis were enriched in healthy controls. These results demonstrate significant alterations in microbial composition and function in periodontitis and suggest genes and metabolic pathways associated with periodontal disease.

Periodontitis and Porphyromonas gingivalis in patients with rheumatoid arthritis.

OBJECTIVE: To examine the degree to which shared risk factors explain the relationship of periodontitis (PD) to rheumatoid arthritis (RA) and to determine the associations of PD and Porphyromonas gingivalis with pathologic and clinical features of RA. METHODS: Patients with RA (n = 287) and patients with osteoarthritis as disease controls (n = 330) underwent a standardized periodontal examination. The HLA-DRB1 status of all participants was imputed using single-nucleotide polymorphisms from the extended major histocompatibility complex. Circulating anti-P gingivalis antibodies were measured using an enzyme-linked immunosorbent assay, and subgingival plaque was assessed for the presence of P gingivalis using polymerase chain reaction (PCR). Associations of PD with RA were examined using multivariable regression. RESULTS: Presence of PD was more common in patients with RA and patients with anti-citrullinated protein antibody (ACPA)-positive RA (n = 240; determined using the anti-cyclic citrullinated peptide 2 [anti-CCP-2] test) than in controls (35% and 37%, respectively, versus 26%; P = 0.022 and P = 0.006, respectively). There were no differences between RA patients and controls in the levels of anti-P gingivalis or the frequency of P gingivalis positivity by PCR. The anti-P gingivalis findings showed a weak, but statistically significant, association with the findings for both anti-CCP-2 (r = 0.14, P = 0.022) and rheumatoid factor (RF) (r = 0.19, P = 0.001). Presence of PD was associated with increased swollen joint counts (P = 0.004), greater disease activity according to the 28-joint Disease Activity Score using C-reactive protein level (P = 0.045), and higher total Sharp scores of radiographic damage (P = 0.015), as well as with the presence and levels of anti-CCP-2 (P = 0.011) and RF (P < 0.001). The expression levels of select ACPAs (including antibodies to citrullinated filaggrin) were higher in patients with subgingival P gingivalis and in those with higher levels of anti-P gingivalis antibodies, irrespective of smoking status. Associations of PD with established seropositive RA were independent of all covariates examined, including evidence of P gingivalis infection. CONCLUSION: Both PD and P gingivalis appear to shape the autoreactivity of RA. In addition, these results demonstrate an independent relationship between PD and established seropositive RA.

Periodontal treatment reduces matrix metalloproteinase levels in localized aggressive periodontitis.

BACKGROUND: Matrix metalloproteinases (MMPs) are a family of host-derived proteinases reported to mediate multiple functions associated with periodontal breakdown and inflammation. High MMP levels in African-American children with localized aggressive periodontitis (LAgP) have been reported previously by the present authors. However, little is known about MMP reductions in gingival crevicular fluid (GCF) after therapy. This study aims to evaluate MMP levels in the GCF after treatment of LAgP and to correlate these levels with clinical response. METHODS: GCF samples were collected from 29 African-American individuals diagnosed with LAgP. GCF was collected from one diseased site (probing depth [PD] >4 mm, bleeding on probing [BOP], and clinical attachment level ≥ 2 mm) and one healthy site (PD ≤ 3 mm, no BOP) from each individual at baseline and 3 and 6 months after periodontal treatment, which consisted of full-mouth scaling and root planing (SRP) and systemic antibiotics. The volume of GCF was controlled using a calibrated gingival fluid meter, and levels of MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, MMP-12, and MMP-13 were assessed using fluorometric kits. RESULTS: MMP-1, MMP-8, MMP-9, MMP-12, and MMP-13 levels were reduced significantly up to 6 months, comparable to healthy sites at the same point. Significant correlations were noted between MMP-2, MMP-3, MMP-8, MMP-9, MMP-12, and MMP-13 levels and percentage of sites with PD >4 mm. MMP-3, MMP-12, and MMP-13 levels also correlated with mean PD of affected sites. CONCLUSION: Treatment of LAgP with SRP and systemic antibiotics was effective in reducing local levels of specific MMPs in African-American individuals, which correlated positively with some clinical parameters.

Non-antibacterial tetracycline formulations: clinical applications in dentistry and medicine.

In 1983, it was first reported that tetracyclines (TCs) can modulate the host response, including (but not limited to) inhibition of pathologic matrix metalloproteinase (MMP) activity, and by mechanisms unrelated to the antibacterial properties of these drugs. Soon thereafter, strategies were developed to generate non-antibacterial formulations (subantimicrobial-dose doxycycline; SDD) and compositions (chemically modified tetracyclines; CMTs) of TCs as host-modulating drugs to treat periodontal and other inflammatory diseases. This review focuses on the history and rationale for the development of: (a) SDD which led to two government-approved medications, one for periodontitis and the other for acne/rosacea and (b) CMTs, which led to the identification of the active site of the drugs responsible for MMP inhibition and to studies demonstrating evidence of efficacy of the most potent of these, CMT-3, as an anti-angiogenesis agent in patients with the cancer, Kaposi's sarcoma, and as a potential treatment for a fatal lung disease (acute respiratory distress syndrome; ARDS). In addition, this review discusses a number of clinical studies, some up to 2 years' duration, demonstrating evidence of safety and efficacy of SDD formulations in humans with oral inflammatory diseases (periodontitis, pemphigoid) as well as medical diseases, including rheumatoid arthritis, post-menopausal osteopenia, type II diabetes, cardiovascular diseases, and a rare and fatal lung disease, lymphangioleiomyomatosis.

Comparison of the virulence of exopolysaccharide-producing Prevotella intermedia to exopolysaccharide non-producing periodontopathic organisms.

BACKGROUND: Evidence in the literature suggests that exopolysaccharides (EPS) produced by bacterial cells are essential for the expression of virulence in these organisms. Secreted EPSs form the framework in which microbial biofilms are built. METHODS: This study evaluates the role of EPS in Prevotella intermedia for the expression of virulence. This evaluation was accomplished by comparing EPS-producing P. intermedia strains 17 and OD1-16 with non-producing P. intermedia ATCC 25611 and Porphyromonas gingivalis strains ATCC 33277, 381 and W83 for their ability to induce abscess formation in mice and evade phagocytosis. RESULTS: EPS-producing P. intermedia strains 17 and OD1-16 induced highly noticeable abscess lesions in mice at 107 colony-forming units (CFU). In comparison, P. intermedia ATCC 25611 and P. gingivalis ATCC 33277, 381 and W83, which all lacked the ability to produce viscous materials, required 100-fold more bacteria (109 CFU) in order to induce detectable abscess lesions in mice. Regarding antiphagocytic activity, P. intermedia strains 17 and OD1-16 were rarely internalized by human polymorphonuclear leukocytes, but other strains were readily engulfed and detected in the phagosomes of these phagocytes. CONCLUSIONS: These results demonstrate that the production of EPS by P. intermedia strains 17 and OD1-16 could contribute to the pathogenicity of this organism by conferring their ability to evade the host's innate defence response.

A comparative evaluation of the sealing ability of 2 root-end filling materials: an in vitro leakage study using Enterococcus faecalis.

OBJECTIVE: The purpose of this study was to evaluate the sealing ability of EndoSequence Bioceramic Root-end Repair (BCRR) material when compared with white mineral trioxide aggregate (WMTA). STUDY DESIGN: Forty single-rooted teeth were instrumented, obturated with gutta-percha, root-end resected, and retrofilled with 2 different materials: white ProRoot MTA (WMTA) (n = 15) and BCRR (n = 15). Unfilled specimens (n = 10) received no retrofill and were used as controls. All groups received E. faecalis in a created reservoir coronal to the root filling and the presence of microleakage was evaluated by counting the colony-forming units from each specimen. The results were analyzed with 1-way analysis of variance. RESULTS: There was no significant difference in leakage between the 2 experimental groups, but there was a significant difference with the control (P ≤ .05). CONCLUSIONS: This study suggests that BCRR is equivalent in sealing ability to WMTA when used as root-end filling material in vitro.

Reduction of two red complex bacteria by sustained-release doxycycline and correlation to improvement in mean pocket depth.

OBJECTIVE: The objective was to evaluate the effects of an 8.5% sustained-release doxycycline-containing polymer formulation (SRDF) on deep pockets (pocket depth [PD] ≥ 7 mm) in chronic periodontitis. Total bacterial counts were used to estimate the number of viable bacteria present before treatment and for up to 6 months posttreatment. METHODS: All sites had PD ≥ 5 mm and bled on probing in 23 subjects who received treatment with SRDF. There was an average of 8.7 teeth or 23 sites for each subject. One deep pocket (≥ 7 mm) in each subject was selected for monitoring. This site was sampled prior to treatment and at 7, 21, 91, and 182 days after SRDF placement. The primary endpoints were changes in the viable counts of two red complex species, Porphyromonas gingivalis and Tannerella forsythia. Secondary endpoints were changes in the number of total anaerobic bacteria recovered and changes in PD. RESULTS: Relative to baseline, SRDF reduced the proportions of P. gingivalis and T. forsythia by 88% and 99%, respectively, at day 7. At the conclusion of the monitoring period--182 days--P. gingivalis and T. forsythia were present but at 19% to 20% of the pretreatment values. Total anaerobic counts were reduced by 96% at day 7; by 87% at day 21; and by 75% and 68% at days 91 and 182, respectively. Mean PD for the sample sites (initially ≥ 7 mm) was reduced 2 mm by day 21, and this difference persisted throughout the study. CONCLUSIONS: This study demonstrates SRDF has a significant effect, not only statistically but also microbially and clinically, on deep periodontal sites in patients with chronic periodontitis. SRDF significantly reduced the number of red complex bacteria P. gingivalis and T. forsythia, as well as the number of total anaerobic bacteria. By day 21, PD was reduced by 2 mm, and this reduction was maintained for at least 6 months posttherapy.

Genetic analysis of mobile tetQ elements in oral Prevotella species.

Prevotella species are members of the bacterial oral flora and are opportunistic pathogens in polymicrobial infections of soft tissues. Antibiotic resistance to tetracyclines is common in these bacteria, and the gene encoding this resistance has been previously identified as tetQ. The tetQ gene is also found on conjugative transposons in the intestinal Bacteroides species; whether these related bacteria have transmitted tetQ to Prevotella is unknown. In this study, we describe our genetic analysis of mobile tetQ elements in oral Prevotella species. Our results indicate that the mobile elements encoding tetQ in oral species are distinct from those found in the Bacteroides. The intestinal bacteria may act as a reservoir for the tetQ gene, but Prevotella has incorporated this gene into an IS21-family transposon. This transposon is present in Prevotella species from more than one geographical location, implying that the mechanism of tetQ spread between oral Prevotella species is highly conserved.

Comparison of bacterial reduction in straight and curved canals using erbium, chromium:yttrium-scandium-gallium-garnet laser treatment versus a traditional irrigation technique with sodium hypochlorite.

INTRODUCTION: This study compared the reduction of Enterococcus faecalis in straight and curved canals using an erbium, chromium:yttrium-scandium-gallium-garnet laser and irrigation with 6.15% sodium hypochlorite (NaOCl). METHODS: Fifty-five single-rooted extracted teeth were divided into straight and curved canal groups. The root lengths were standardized (14.0mm) and NiTi instruments were used to prepare the canals to a size #40/0.06 taper. Irrigation was performed with 6.15% NaOCl and RCPrep (Premier Dental Products Co, Plymouth Meeting, PA) as lubricant. The smear layer was removed with 17% EDTA. The samples were sterilized, inoculated with E. faecalis, and incubated for 48 hours at 37 degrees in a CO(2) chamber. They were then divided into 7 groups: NaOCl in straight canals (NS); NaOCl in curved canals (NC); laser in straight canals (LS); laser in curved canals (LC); positive control straight canals (PCS); positive control curved canals (PCC); and negative control (NegC). Bacterial reduction was measured by counting the colony-forming units (CFUs) and determining the optical density. RESULTS: Groups NS, NC, and LS exhibited bacterial growth in 1 out of 10 samples (10%). In group LC, three out of 10 samples (30%) showed bacterial growth. Kruskal-Wallis showed a statistically significant difference between all treatment groups and the positive controls (p<0.001). Analysis of variance showed a statistical significant difference in optic density between experimental and positive controls. CONCLUSIONS: Traditional irrigation techniques using 6.15% NaOCl effectively eliminated all bacteria in straight and curved canals. Er,Cr:YSGG laser also effectively removed all bacteria from straight canals. However, in three curved canals, even though there were significant bacterial reductions, they failed to render canals completely free of bacteria.

Treating chronic periodontitis: current status, challenges, and future directions.

Periodontitis affects roughly one-third of the US population. A timely diagnosis of chronic periodontitis at its earliest stage is essential to avoid more challenging severe stages of the disease. Most cases of slight and moderate chronic periodontitis can be successfully managed by mechanical removal and/or reduction of subgingival bacterial biofilms and calculus. However, any factor that affects either the local environment or the host response may contribute to progression of the disease and a poor treatment response. Thus, it is essential that clinicians are aware of etiologic and risk factors associated with disease development and progression in order to plan and execute a successful treatment. This paper reviews a variety of risk factors, both local and systemic, that can impact the successful treatment of chronic periodontitis.

Gene expression profile and pathogenicity of biofilm-forming Prevotella intermedia strain 17.

BACKGROUND: Prevotella intermedia (P. intermedia), a gram-negative, black-pigmented anaerobic rod, has been implicated in the development of chronic oral infection. P. intermedia strain 17 was isolated from a chronic periodontitis lesion in our laboratory and described as a viscous material producing strain. The stock cultures of this strain still maintain the ability to produce large amounts of viscous materials in the spent culture media and form biofilm-like structures. Chemical analyses of this viscous material showed that they were mainly composed of neutral sugars with mannose constituting 83% of the polysaccharides. To examine the biological effect of the extracellular viscous materials, we identified and obtained a naturally-occurring variant strain that lacked the ability to produce viscous materials in vitro from our stock culture collections of strain 17, designated as 17-2. We compared these two strains (strains 17 versus 17-2) in terms of their capacities to form biofilms and to induce abscess formation in mice as an indication of their pathogenicity. Further, gene expression profiles between these two strains in planktonic condition and gene expression patterns of strain 17 in solid and liquid cultures were also compared using microarray assays. RESULTS: Strain 17 induced greater abscess formation in mice as compared to that of the variant. Strain 17, but not 17-2 showed an ability to interfere with the phagocytic activity of human neutrophils. Expression of several genes which including those for heat shock proteins (DnaJ, DnaK, ClpB, GroEL and GroES) were up-regulated two to four-fold with statistical significance in biofilm-forming strain 17 as compared to the variant strain 17-2. Strain 17 in solid culture condition exhibited more than eight-fold up-regulated expression levels of several genes which including those for levanase, extracytoplasmic function-subfamily sigma factor (sigmaE; putative) and polysialic acid transport protein (KpsD), as compared to those of strain 17 in liquid culture media. CONCLUSION: These results demonstrate that the capacity to form biofilm in P. intermedia contribute to their resistance against host innate defence responses.