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Biomedical subjects

I Madinier

Publications and source records attributed to I Madinier.

At least 19 recordsLinked to original sources

In vitro antiseptic properties of an ammonium compound combined with denture base acrylic resin.

BACKGROUND: Denture base acrylic resin is easily colonised by oral endogenous bacteria and Candida spp., and eventually by extra-oral species such as Staphylococcus spp., Pseudomonadaceae or members of Enterobacteriaceae. This microbial reservoir can be responsive for denture related stomatitis and aspiration pneumonia, a life-threatening infection especially in geriatric patients. However, the oral and denture hygiene of dependent elderly individuals is extremely poor. OBJECTIVE: This in vitro study aimed to determine the per cent of a quaternary ammonium compound heat-polymerised in acrylic resin necessary to obtain denture base displaying antiseptic properties. DESIGN: Acrylic resin discs containing 2-50% ammonium polymer (Poly 202063A; 0% control) were soaked in artificial saliva for 4 weeks. Resin discs were incubated for 24 hours with Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa [37 degrees C, brain-heart infusion (BHI) broth and phosphate-buffered saline (PBS) buffer] and Candida albicans (30 degrees C, Schaedler broth), in 15 ml (168 discs) and 600 microl (168 discs) of inoculum. Microbial growth was verified at t 0 hours and t 24 hours. Data were recorded as the mean of three colony forming unit (CFU) numerations. The borderline of antimicrobial effect was determined at 0.1% viable cells. RESULTS: In 600 microl of PBS inoculum, resin specimens had a bactericidal effect (E. coli and S. aureus: 2%; P. aeruginosa: 10%) and a fungicidal effect (C. albicans: 50%). Long-term stability and toxicity in vivo studies are now required. CONCLUSION: A 2% quaternary ammonium compound polymerised with a denture acrylic resin displayed antiseptic properties after a 4-week soaking period in artificial saliva. Such antiseptic denture base could help geriatric patients to improve their oral health.

Acrylic Resins↗

In vitro new dialysis protocol to assay the antiseptic properties of a quaternary ammonium compound polymerized with denture acrylic resin.

AIMS: To develop an in vitro protocol in order to assess the antiseptic properties of a quaternary ammonium compound polymerized with acrylic denture resin base, using experimental resin discs and dialysis membranes. METHODS AND RESULTS: Experimental acrylic resin discs were polymerized with Poly 202063A, an ammonium compound (2-50%). Antiseptic properties were assayed against two reference strains (Escherichia coli, Staphylococcus aureus) and a laboratory strain (Candida albicans), using three different conditions (test A, B and C). In test A, according to classical protocols the resin discs were first soaked in large volumes of microbial inoculum (45 ml). An original dialysis protocol was then designed to recreate the small biofilm volume on the prosthetic surface. In test B, discs and bacterial inoculum (600 microl) were introduced in a dialysis bag and dialysed against a sterile buffer. A bactericidal effect was observed against E. coli and Staph. aureus (<0.1% viable cells in initial bacterial suspension). A dose-dependent fungistatic effect was observed against C. albicans. Finally, in test C discs and sterile buffer (600 microl) were introduced in a dialysis bag and dialysed against microbial inoculum. Reduced activity was found outside the dialysis bag, demonstrating that free ammonium was able to diffuse through the dialysis membrane, displaying antiseptic properties. CONCLUSIONS: The present protocol demonstrated that a quaternary ammonium compound remains efficient after heat polymerization with an acrylic denture base resin, both in immediate and distant microbial environments. SIGNIFICANCE AND IMPACT OF THE STUDY: Such removable prosthetic devices with intrinsic antiseptic properties would contribute to improve the long-term management of denture stomatitis.

Acrylic Resins↗

[Phenotypes of beta-lactam resistance in the genus Aeromonas].

This work aimed to investigate resistance profiles towards beta-lactam antibiotics in correlation with beta-lactamases production in the genus Aeromonas. In a series of 417 wild-type strains, biochemical identification and testing with 11 beta-lactams by the disk-diffusion method revealed 5 predominant phenotypes: A. hydrophila complex/class B, C and D beta-lactamases; A. caviae complex/class C and D beta-lactamases; A. veronii complex/class B and D beta-lactamases; A. schubertii spp./class D beta-lactamase; A. trota spp./class C beta-lactamase. A subgroup of 64 representative strains was submitted to MIC determination with 8 beta-lactam compounds alone and in combination with 3 beta-lactamase inhibitors (clavulanic acid, tazobactam and BRL 42715). Visualisation of beta-lactamases and pI determination were performed in all these 64 isolates by isoelectric focusing from crude extracts. The different Aeromonas species produced 1 to 3 of the following inducible enzymes: an imipenemase with low expression, which is difficult to detect with routine phenotype studies (class B, pI 8, imipenem MIC > 2 micrograms/ml), a cephalosporinase (class C, pI > 7 +/- 0.5, cephalothin MIC > 256 micrograms/ml), and an oxacillinase widely produced in the genus Aeromonas (class D, pI > 8.5, ticarcillin MIC > 256 micrograms/ml). In Aeromonas spp. resistance profile to beta-lactam antibiotics is correlated with naturally occurring phenotypes of beta-lactamases production. As a conclusion, the characterisation of these different enzymes is of therapeutic and taxonomic interest, in species notoriously difficult to identify.

Aeromonas↗

Induced colistin resistance as an identifying marker for Aeromonas phenospecies groups.

AIMS: To investigate the taxonomic interest of colistin resistance as an identifying marker for Aeromonas phenospecies groups. METHODS AND RESULTS: Colistin resistance was investigated in 387 Aeromonas isolates identified at species level using a 14-test format protocol with miniaturized tests combined with determination of urocanic acid utilization whenever necessary. Colistin resistance, determined by the disc diffusion method, was unreliable when compared with minimum inhibitory concentration (MIC) determination. In some strains, the MIC values and resistance rates of colistin could be increased after overnight induction with a 50- microg colistin disc in 20 ml of Mueller-Hinton broth (2.5 mg l(-1)). Colistin-induced resistance level was raised to 85.8% in the Aeromonas hydrophila complex, 2.1% in the A. caviae complex and 2.5% in the A. veronii complex except for A. jandaei (100% colistin resistant). This new marker allowed the identification of 96.2 and 93.6% of Aeromonas isolates to phenospecies and species level, respectively. CONCLUSIONS: Colistin-induced colistin resistance is a new phenotypic marker for Aeromonas isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: With the present protocol, colistin resistance determination may improve the identification of Aeromonas isolates to phenogroup level, when results obtained by conventional biochemical methods are ambiguous.

Aeromonas↗

High prevalence of cfxA beta-lactamase in aminopenicillin-resistant Prevotella strains isolated from periodontal pockets.

This prospective study was designed to investigate amoxicillin-resistant oral anaerobes, and to identify their beta-lactamase-encoding genes. Three subgingival bacterial samples were collected from 12 patients suffering from periodontitis. One to seven beta-lactamase-producing strains were obtained from each patient, mostly belonging to the Prevotella genus (Bacteroides eggerthii, 2/35 strains; Prevotella sp., 33/35 strains). PCR assays were used to detect cfxA and cepA/cblA, the genes encoding class A/group2e beta-lactamases previously described in the Bacteroides fragilis group. The present investigation confirmed the role of Prevotella species as beta-lactamase producers in periodontal pockets. Additionally, this PCR screening showed (1): the high prevalence of CfxA beta-lactamase production by aminopenicillin-resistant Prevotella (32/33: 97.0% positive strains) vs. cepA/cblA (1/33: 3.0% positive strains), and (2) the presence of cfxA in the periodontal reservoir in the absence of antimicrobial therapy during the previous 6 months.

Amoxicillin↗

[Drug-induced oral ulcerations].

Different side effects of drugs have been described in the oral cavity, including oral ulcerations. Direct contact between drugs and oral mucosa may induce chemical burn or local hypersensitivity. Less frequently, these drug-induced oral ulcerations are part of a complex reaction with cutaneous or systemic manifestations. Sometimes, one or more oral ulcerations appear as the main side-effect of a drug, or exceptionally as solitary lesions. Solitary oral ulcerations usually appear after few weeks of treatment. In most of cases, these lesions resist to conventional treatments, with a rapid healing following the suppression of the responsible drug. This diagnosis is usually difficult, particularly with patients receiving multiple drug therapy. Besides, special attention must be paid to new drugs. Oral ulcerations following symptoms of burning mouth, metallic taste, dysgueusia or agueusia are strongly suggestive of a pharmacological origin. Most of the molecules able to induce solitary oral ulcerations are commonly prescribed in a) rheumatology: NSAI (diclofenac, flurbiprofen, indomethacin, naproxen), long-term rheumatoid arthritis therapy (azathioprine, methotrexate, penicillamine, gold compounds, tiopronin); b) cardiology: angiotensin-converting-enzyme inhibitors (captopril, enalapril), angiotensin 2-receptor antagonist (losartan), anti-angorous (nicorandil), c) psychiatry: antidepressants (fluoxetine, lithium), d) AIDS therapy (foscarnet, zalcitabine).

Anesthetics, Local↗

Prevalence of beta-lactamase-producing strains among 149 anaerobic gram-negative rods isolated from periodontal pockets.

In a prospective study, 47 adults presenting a rapidly progressive periodontitis were selected in order to evaluate the prevalence of beta-lactamase-producing strains among oral anaerobic gram-negative rods. Predominant anaerobes were identified from two of the deepest periodontal pockets. beta-Lactamase-positive strains fulfilled to at least two of three criteria: positive nitrocefin test, penicillin Etest minimal inhibitory concentration > 1 microgram/ml, and disk diffusion synergy between amoxycillin and clavulanic acid > 10 mm. At least one beta-lactamase-producing strain was found in 53.2% of patients and 39.4% of the periodontal pockets investigated. Prominent beta-lactamase-positive species were Prevotella buccae and Prevotella intermedia (respectively 16 of 38: 42% and 18 of 52: 35% positive strains), followed by Prevotella bivia, Prevotella disiens, Prevotella denticola and Fusobacterium nucleatum (respectively 1 of 6: 17%, 1 of 10: 10%, 1 of 10: 10%, and 1 of 13: 8% positive strains). No beta-lactamase producer could be evidenced in Porphyromonas gingivalis (10 strains tested). All the beta-lactamase-positive strains with the nitrocefin test had penicillin minimal inhibitory concentrations > 1 microgram/ml with the Etest, and a strong synergy between amoxicillin and clavulanic acid was always observed.

Adult↗

In vitro antifungal resistance of oral Candida albicans strains in non-AIDS patients.

Some cases of oral candidosis are refractory to antifungal treatment. This might be related to development of resistant Candida strains, but susceptibility testing is not standardized and not routinely available, and information related to this problem is scarce in non-AIDS patients. In this study, the in vitro antifungal resistance of oral Candida albicans strains was evaluated. The strains were obtained from a cohort of 72 HIV-negative patients with oral yeast carriage and clinical complaint. Laboratory identification revealed C. albicans in 93% of cases. None of these oral C. albicans isolates showed in vitro resistance to polyenes, but they showed varying resistance levels to fluorocytosine and azoles. This study confirms the usefulness of standardizing susceptibility testing so that it could be routinely available and of realizing a mycological diagnosis including an antifungigram when oral candidosis is suspected, whenever antifungal treatment with azoles is planned.

Antifungal Agents↗

[Buccal dryness, xerostomia and measurement of salivary secretory activity].

Xerostomia is a marked reduction in saliva production and may occur as an early symptom of various systemic diseases. It is also secondary to the administration of numerous drugs. Severity of salivary gland dysfunction cannot be predicted from subjective reports of oral dryness by patient, and accurate assessments of salivary gland function should be managed. Several procedures for saliva samplings and secretory activity measurements have been reported. In normal individuals, the mean values of unstimulated whole saliva was slightly higher in males (0.42 ml/min) than in females (0.37 ml/min). Corresponding mean values for stimulated whole saliva are 1.77 ml/min and 1.38 ml/min. Unstimulated whole saliva collection during 15 min is recommended as the most reliable test for clinical diagnosis. It is found that an unstimulated salivary flow of 0.1 ml/min represents the cut-off limit for the diagnosis of xerostomia.

Adolescent↗

[Drug-induced xerostomia].

Hyposalivation is related to decreased salivary flow, with xerostomia as an ultimate degree. Prolonged severe hyposalivation or xerostomia may induce oral pain, poor tolerance to dentures, loss in taste acuity and increased incidence of oral infections: gingivitis, periodontitis, oral candidosis, infectious sialadenitis and multiple dental caries. Most of the time hyposalivation is a reversible drug-induced side-effect. Hyposalivation is frequent, particularly in elderly people with numerous drugs prescribed on a long-term continuous basis, and in psychiatric patients. It remains a neglected clinical problem. Besides the well-known antimuscarinics, antihistaminics, imipraminic antidepressants and phenothiazic neuroleptics, many drugs may induce hyposalivation. This work aims to review drug-induced xerostomia in 1997 (French pharmacopeae), and high-risk associations.

Humans↗

Epstein-Barr virus DNA detection in gingival tissues of patients undergoing surgical extractions.

The main oral manifestation of Epstein-Barr virus (EBV) infection is hairy leukoplakia, a lesion associated with the acquired immunodeficiency syndrome (AIDS) and occasionally in other immunocompromised patients. However, the recent literature describes the presence of viral genome in clinically normal oral tissues. The purpose of this work was to investigate these occult EBV infections in gingival epithelium. The Southern blot method with 32P-radiolabelled DNA probes under stringent conditions was applied to 20 interproximal gingival papillae specimens and revealed homologous EBV sequences in 4 of 10 AIDS patients as well as in 4 of 10 HIV negative patients. In order to determine whether EBV has a predilection for the gingival tissues, samples of nasal, laryngeal and oral mucosa, other than gingival mucosa, were collected from 10 HIV-negative patients undergoing surgical treatment for a variety of clinical conditions. None of these extra-periodontal mucosal specimens contained homologous EBV DNAs, except an edentulous palatal gingival specimen. With the present detection of EBV DNAs in the gingival tissues of patients undergoing surgical extractions, it would be of interest to investigate more systematically these subclinical infections in order to determine their exact implications in oral disease.

Acquired Immunodeficiency Syndrome↗

Southern blot detection of human papillomaviruses (HPVs) DNA sequences in gingival tissues.

The highly sensitive and specific methods of molecular biology emphasize the frequency of subclinical infections in the genital tract tissues by the human papillomaviruses (HPVs). The purpose of this work was to investigate occult viral infections by the HPV type 6, 11, 16, and 18 in the gingival tissues. The Southern blot method with 32P-radiolabeled DNA probes applied under stringent conditions to 20 interproximal gingival papilla specimens revealed homologous viral sequences in 1 of 6 cases of adult periodontitis (HPV 16), 1 of 2 cases of rapidly progressive periodontitis (RPP) (HPV 6/HPV 11), 2 of 2 cases of acute gingivitis in psychiatric institutionalized patients (HPV 6; HPV 6/HPV 11), and 2 of 10 cases of acute gingivitis in AIDS patients (HPV 6/HPV 11/HPV 16; HPV 6). No periodontal or extra-periodontal specimen hybridized with the HPV 18 probe. Simultaneous hybridization with two or three HPV types was common (3/6 cases). The present detection of HPV 6, 11, 16 DNAs or related-DNAs in periodontal tissues without obvious clinical signs of viral infection suggests that the gingival epithelium may act as a reservoir.

Adult↗

[Oral bacterial flora and its pathogenic potential].

The oral flora is a complex body formed by at least a hundred bacterial species which can be more or less regular residents in the oral cavity. Thanks to a developing taxonomy related to progress made in bacterial identification, these oral species can be separated into five groups based Gram staining and morphology: the Gram positive cocci group (Streptococcus, Staphylococcus and related geni), the Gram negative cocci group (Neisseria, Veillonella and related geni), the Gram positive bacilli group (Corynebacterium, Actinomyces, Lactobacillus, Methanobrevibacter and related geni), the Gram negative bacilli group (Haemophilus, Campylobacter, Bacteroides and related geni) and finally the spirochete group (Treponema).

Bacteria↗