Antimicrobial resistance and virulence of subgingival staphylococci isolated from periodontal health and diseases.

The dysbiotic biofilm of periodontitis may function as a reservoir for opportunistic human pathogens of clinical relevance. This study explored the virulence and antimicrobial susceptibility of staphylococci isolated from the subgingival biofilm of individuals with different periodontal conditions. Subgingival biofilm was obtained from 142 individuals with periodontal health, 101 with gingivitis and 302 with periodontitis, and cultivated on selective media. Isolated strains were identified by mass spectrometry. Antimicrobial susceptibility was determined by disk diffusion. The mecA and virulence genes were surveyed by PCR. Differences among groups regarding species, virulence and antimicrobial resistance were examined by Chi-square, Kruskal-Wallis or Mann-Whitney tests. The overall prevalence of subgingival staphylococci was 46%, especially in severe periodontitis (> 60%; p < 0.01). S. epidermidis (59%) and S. aureus (22%) were the predominant species across groups. S. condimenti, S. hominis, S. simulans and S. xylosus were identified only in periodontitis. High rates of resistance/reduced sensitivity were found for penicillin (60%), amoxicillin (55%) and azithromycin (37%), but multidrug resistance was observed in 12% of the isolates. Over 70% of the mecA + strains in periodontitis were isolated from severe disease. Higher detection rates of fnB + isolates were observed in periodontitis compared to health and gingivitis, whereas luxF/luxS-pvl + strains were associated with sites with deep pockets and attachment loss (p < 0.05). Penicillin-resistant staphylococci is highly prevalent in the subgingival biofilm regardless of the periodontal status. Strains carrying virulence genes related to tissue adhesion/invasion, inflammation and cytotoxicity support the pathogenic potential of these opportunists in the periodontal microenvironment.

Inflammatory and Oxidative Stress Markers in Experimental Allergic Asthma.

Ovalbumin-induced allergic lung inflammation (ALI) is a condition believed to be mediated by cytokines, extracellular matrix remodeling, and redox imbalance. In this study, we evaluated pulmonary function together with inflammatory markers as interleukin-4 (IL-4), myeloperoxidase (MPO), eosinophil cells, and redox markers in the lungs of BALB/c mice after ovalbumin (OVA) sensitization and challenge. Our results showed an increase in bronchial hyperresponsiveness stimulated by methacholine (Mch), inflammatory cell influx, especially eosinophils together with an increase of high mobility group box 1 (HMGB1) and altered lipid peroxidation (LP) and antioxidant defenses in the OVA group compared to the control group (p ≤ 0.5). Thus, we demonstrated that OVA-induced ALI altered redox status concomitantly with impaired lung function, which was associated with HMGB1 expression and proteolytic remodeling. Taken together all results found here, we may suggest HMGB1 is an important therapeutic target for asthma, once orchestrates the redox signaling, inflammation, and remodeling that contribute to the disease development.

Periodontal-disease-associated biofilm: A reservoir for pathogens of medical importance.

The ecological diversity of the periodontal microenvironment may provide suitable conditions for the colonization of species not usually considered members of the oral microbiota. In this investigation, we aimed to determine the prevalence and levels of pathogenic species of medical relevance in the microbiota of individuals with distinct periodontal clinical status. Subgingival biofilm was obtained from patients with periodontal health (H, n = 81), gingivitis (G, n = 55), generalized aggressive (AgP, n = 36) or chronic periodontitis (CP, n = 98), and analyzed for 39 microbial taxa using a checkerboard DNA-DNA hybridization technique. Microbial differences among groups, as well as associations between clinical and microbiological parameters were sought by non-parametric and univariate correlation tests. Neisseria spp., Peptostreptococus anaerobius, Candida albicans, enterobacteria, Pseudomonas aeruginosa, Eubacterium saphenum, Clostridium difficile and Olsenella uli were detected in high mean prevalence and counts in the subgingival microbiota of the study population. Species that were more related to periodontal inflammation and tissue destruction at the patient and site levels included enterobacteria, C. albicans, Neisseria spp., P. aeruginosa, O. uli, Hafnia alvei, Serratia marcescens and Filifactor alocis (p < 0.05). In contrast, Fusobacterium necrophorum, Lactobacillus acidophilus, Staphylococcus aureus and Streptococcus pneumoniae were associated with periodontal health (p < 0.05). Pathogenic species of medical importance may be detected in high prevalence and levels in the periodontal microbiota. Regardless of their role in periodontal health or disease, the periodontal biofilm may be a source for dissemination and development of systemic infections by these pathogenic microorganisms.

Redox markers and inflammation are differentially affected by atorvastatin, pravastatin or simvastatin administered before endotoxin-induced acute lung injury.

Statins are standard therapy for the treatment of lipid disorders, and the field of redox biology accepts that statins have antioxidant properties. Our aim in this report was to consider the pleiotropic effects of atorvastatin, pravastatin and simvastatin administered prior to endotoxin-induced acute lung injury. Male mice were divided into 5 groups and intraperitoneally injected with LPS (10 mg/kg), LPS plus atorvastatin (10 mg/kg/day; A + LPS group), LPS plus pravastatin (5 mg/kg/day; P + LPS group) or LPS plus simvastatin (20 mg/kg/day; S + LPS group). The control group received saline. All mice were sacrificed one day later. There were fewer leukocytes in the P + LPS and S + LPS groups than in the LPS group. MCP-1 cytokine levels were lower in the P + LPS group, while IL-6 levels were lower in the P + LPS and S + LPS groups. TNF-α was lower in all statin-treated groups. Levels of redox markers (superoxide dismutase and catalase) were lower in the A + LPS group (p < 0.01). The extent of lipid peroxidation (malondialdehyde and hydroperoxides) was reduced in all statin-treated groups (p < 0.05). Myeloperoxidase was lower in the P + LPS group (p < 0.01). Elastance levels were significantly greater in the LPS group compared to the statin groups. Our results suggest that atorvastatin and pravastatin but not simvastatin exhibit anti-inflammatory and antioxidant activity in endotoxin-induced acute lung injury.

Endotoxin-induced acute lung injury is dependent upon oxidative response.

The aim of the present study was to investigate the involvement of oxidative stress in acute lung injury (ALI) induced by lipopolysaccharide (LPS) and its effects upon cell structure, function and inflammation. In total, 108 male C57BL/6 mice were divided into seven groups: CTR Group (50 µL of saline) administered intratracheally (i.t.), LPS 6 h (10 µg of LPS - i.t.), LPS 12 h (10 µg of LPS - i.t.), LPS 24 h (10 µg of LPS - i.t.), LPS 48 h (10 µg of LPS - i.t.), LPS 24 h (10 µg - i.t.) + NAC 40 mg/kg (gavage) and 24 h LPS (10 µg - i.t.) + NAC 100 mg/kg (gavage). The antioxidant treatment protected the lungs from stress in the first 12 h, but significant oxidative stress induction was observed at the 24-hour time point, and, after 48 h, there was no protection exerted by the antioxidant treatment. NAC (N-acetylcysteine) reversed the elastance parameters, and ΔP1 and ΔP2 compared with 24 h LPS alone. NAC reduced the number of inflammatory cells in histology analysis when compared with the 24 h LPS alone-treated group. NAC also inhibited the transcription of NFκB, IL-6, TNF-α and COX2 usually induced by LPS. Our results suggest that oxidative stress plays an important role in structural, functional and inflammatory responses in the ALI model.

Residual oil fly ash worsens pulmonary hyperreactivity in chronic allergic mice.

BALB/c mice received saline (SAL groups) or ovalbumin (OVA groups) intraperitoneally (days 1, 3, 5, 7, 9, 11 and 13). After 27 days, a burst of intratracheal OVA or SAL (days 40, 43 and 46) was performed. Animals were then divided into four groups (N=8, each) and intranasally instilled with saline (SAL-SAL and OVA-SAL) or residual oil fly ash (SAL-ROFA and OVA-ROFA). 24h later, total, initial and difference resistances (Rtot, Rinit, Rdiff) and static elastance (Est) were measured. Lung responsiveness to methacholine was assessed as slope and sensitivity of Est, Rtot, Rinit, and Rdiff. Lung morphometry (collapsed and normal areas and bronchoconstriction index) and cellularity (polymorphonuclear, mononuclear and mast cells) were determined. OVA or ROFA similarly impaired lung mechanics and increased the amount of polymorphonuclear cells and collapsed areas. OVA-ROFA showed even higher hyperresponsiveness, bronchoconstriction and mast cell infiltration. Thus, we concluded that ROFA exposure may add an extra burden to hyperresponsive lungs.

Comparative respiratory toxicity of particles produced by traffic and sugar cane burning.

The impact of particle emissions by biomass burning is increasing throughout the world. We explored the toxicity of particulate matter produced by sugar cane burning and compared these effects with equivalent mass of traffic-derived particles. For this purpose, BALB/c mice received a single intranasal instillation of either distilled water (C) or total suspended particles (15 microg) from an urban area (SP group) or biomass burning-derived particles (Bio group). Lung mechanical parameters (total, resistive and viscoelastic pressures, static elastance, and elastic component of viscoelasticity) and histology were analyzed 24h after instillation. Trace elements and polycyclic aromatic hydrocarbons (PAHs) metabolites of the two sources of particles were determined. All mechanical parameters increased similarly in both pollution groups compared with control, except airway resistive pressure, which increased only in Bio. Both exposed groups showed significantly higher fraction area of alveolar collapse, and influx of polymorphonuclear cells in lung parenchyma than C. The composition analysis of total suspended particles showed higher concentrations of PAHs and lower concentration of metals in traffic than in biomass burning-derived particles. In conclusion, we demonstrated that a single low dose of ambient particles, produced by traffic and sugar cane burning, induced significant alterations in pulmonary mechanics and lung histology in mice. Parenchymal changes were similar after exposure to both particle sources, whereas airway mechanics was more affected by biomass-derived particles. Our results indicate that biomass particles were at least as toxic as those produced by traffic.