ObjectivesThis study evaluated the resistance to antimicrobials of aerobes and facultative anaerobes isolated from patients wearing complete dentures, patients with gingivitis and periodontitis, and periodontally health subjects. Material and methodsThree hundred and four isolates were tested. The minimal inhibitory concentrations of the drugs were evaluated through the agar dilution method using Mueller-Hinton agar. ResultsThe most active antimicrobial drugs were the carbapenems (meropenem and imipenem), and resistance to these drugs was restrict to 1.6-2.3% of the isolates, as well as ciprofloxacin and rifampin. Microbial resistance to ampicillin, amoxicillin/clavulanic acid, cefoxitin, cephalothin, amikacin, chloramphenicol and nalidixic acid was particularly high. In most cases, the resistance to β-lactams was mediated by the production of hydrolytic enzymes, especially in gram-negative enteric rods, while enterococci did not evidence production of these enzymes. The association amoxicillin/clavulanic acid was not effective in 28.3% of the tested isolates. ConclusionsThe results of this investigation confirmed that the oral cavity of patients with periodontitis and gingivitis, and particularly edentulous patients wearing complete dentures, could harbor microorganisms with several antimicrobial resistance markers, and these microorganisms are frequently implicated in multiresistant, systemic, oral or nosocomial infections.

Chronic osteomyelitis of maxilla and mandible is rare in industrialized countries and its occurrence in developing countries is associated with trauma and surgery, and its microbial etiology has not been studied thoroughly. The aim of this investigation was to evaluate the microbiota associated with osteomyelitis of mandible or maxilla from some Brazilian patients. After clinical and radiographic evaluation, samples of bone sequestra, purulent secretion, and biopsies of granulomatous tissues from twenty-two patients with chronic osteomyelitis of mandible and maxilla were cultivated and submitted for pathogen detection by using a PCR method. Each patient harbored a single lesion. Bacterial isolation was performed on fastidious anaerobe agar supplemented with hemin, menadione and horse blood for anaerobes; and on tryptic soy agar supplemented with yeast extract and horse blood for facultative bacteria and aerobes. Plates were incubated in anaerobiosis and aerobiosis, at 37 o C for 14 and 3 days, respectively. Bacteria were cultivated from twelve patient samples; and genera Actinomyces, Fusobacterium, Parvimonas, and Staphylococcus were the most frequent. By PCR, bacterial DNA was detected from sixteen patient samples. The results suggest that cases of chronic osteomyelitis of the jaws are usually mixed anaerobic infections, reinforcing the concept that osteomyelitis of the jaws are mainly related to microorganisms from the oral environment, and periapical and periodontal infections may act as predisposing factors.

A ggregatibacter actinomycetemcomitans is associated with periodontal disease, especially localized aggressive periodontitis, produces a potent leukotoxin and its distribution is influenced by ethnic characteristics of the population.Objective:Using culture and polymerase chain reaction (PCR) techniques, this study evaluated the occurrence of this microorganism and the distribution of leukotoxic strains isolated from Indians belonging to the Umutima Reservation, Mato Grosso, Brazil.Material and Methods:Forty-eight native Brazilians with gingivitis and 38 with chronic periodontitis, belonging to Umutina, Paresi, Bororo, Bakairi, Kayabi, Irantxe, Nambikwara and Terena ethnicities, were studied. Subgingival, supragingival and saliva samples of each patient were collected and transferred to VMGA III medium and to ultra pure Milli Q water. Bacteria were grown on TSBV agar and incubated in anaerobiosis (90% N2 + 10% CO2) at 37°C for 72 h. The presence of the ltx promoter was determined by PCR, and a 530 bp deletion in the promoter was evaluated by using specific primers.Results: A. actinomycetemcomitans was isolated from 8.33% of saliva, supragingival and subgingival samples from patients with gingivitis and from 18.42% of saliva and supragingival biofilm, and 26.32% subgingival biofilm from patients with chronic periodontitis. By PCR, the bacterial DNA was detected in 8.33% of saliva, supragingival and subgingival biofilms from patients with gingivitis and from 23.68% of saliva, 28.95% supragingival biofilm and 34.21% subgingival biofilm from patients with periodontitis. All strains were grouped as non-JP2 clones based on the absence of deletion in the leukotoxin promoter. Differences among the microbial and clinical parameters in patients were analyzed by using the Mann-Whitney, Chi-square or Fisher's exact tests.Conclusions:The present results suggest that A. actinomycetemcomitans can be related to the attachment loss in this population, but the presence of minimally leukotoxic strains, as well as its role in the pathogenesis of the periodontitis in these native Brazilians need to be further investigated.

GAETTI-JARDIM JÚNIOR, E.; VASCONCELOS, A. C. de. Retention of oral microorganisms on conventional and resin-modified glass-ionomer cements. Pesqui Odontol Bras, v. 15, n. 3, p. 196-200, jul./set. 2001. Secondary caries are a worldwide public and socioeconomic problem. The placement of restorations can lead to the development of environmental conditions favorable to microbial colonization, especially on the tooth/restoration interface, which is a predisposing factor for secondary caries. The aim of this study was to evaluate microbial retention on conventional (Chelon-Fil and Vidrion R) and resin-modified (Vitremer and Fuji II LC) glass-ionomer cements, in situ, using a hybrid composite resin (Z100) as a control. Twelve volunteers wore Hawley appliances with specimens made of all tested filling materials for 7 days. The specimens were then removed from the appliances and transferred to tubes containing 2.0 ml of Ringer-PRAS. Microorganisms from the samples were inoculated onto blood agar and Mitis Salivarius Bacitracin agar and incubated under anaerobiosis (90% N2, 10% CO2), at 37°C, for 10 and 2 days, respectively. The resin-modified glass-ionomer cements and the composite resin retained the same levels of microorganisms on their surfaces. The resin-modified glass-ionomers retained less mutans streptococci than the composite resin and conventional glass-ionomer cements. The conventional glass-ionomer cements retained less mutans streptococci than the composite resin, but that difference was not statistically significant.

The aim of the present study was to evaluate the effects of local tetracycline on the occurrence of alveolar osteitis in rats, and on the microbiota associated to this infection. Forty Wistar rats were randomly assigned to 4 groups (n=10): I - the rats had the maxillary right incisor extracted and the alveolar wound did not receive any treatment; II - adrenaline and Ringer-PRAS were introduced into the alveolar wound; III - the alveolar wound was irrigated with sterile saline; and IV - the alveolar wound was irrigated with an aqueous solution of tetracycline. Microbial samples from the alveolar wounds were collected 2 days after surgery and inoculated on blood agar (with and without 8 microg/mL of tetracycline) and other selective media, and were incubated in either aerobiosis or anaerobiosis at 37 degrees C, for 2 to 14 days. It was verified that tetracycline reduced the occurrence of alveolar osteitis in the rats and caused significant changes in the microbiota of the surgical sites, decreasing the number of anaerobes and increasing the participation of tetracycline-resistant and multi-resistant microorganisms.

The aim of this study was to determine the frequency of isolation of Actinobacillus actinomycetemcomitans (Aa) in 100 patients with chronic periodontitis, 14 patients with aggressive periodontitis, 142 pre-school children with gingivitis and 134 periodontally healthy subjects. Samples of subgingival plaque were taken using sterilized paper points introduced into periodontal pockets or gingival crevice for 60 seconds and inoculated on TSBV agar, which was incubated under anaerobiosis at 37°C, for 4 days. Microbial identification was performed through biochemical methods and morphocellular and morphocolonial analysis. Aa was detected in 40.3% of healthy subjects, 68% of patients with chronic periodontitis, 92.86% of patients with aggressive periodontitis and 40.14% of children with gingivitis. The rate of recovery of Aa in the tested human groups proved to be higher than previously reported and in agreement with participation of this facultative anaerobe as a member of native microbiota of the periodontium and its relation with aggressive and chronic periodontitis in Brazil.

Fusobacterium nucleatum is a strict anaerobe and is indigenous of the human oral cavity. This organism is commonly recovered from different monomicrobial and mixed infections in humans and animals. In this study, the plasmid profile, the plasmid stability and the penicillin-resistance association in oral F. nucleatum isolated from periodontal patients, healthy subjects and Cebus apella monkeys were evaluated. Forty-five F. nucleatum strains from patients, 38 from healthy subjects and seven from C. apella were identified and analyzed. Plasmid extraction was performed in all the isolated strains. These elements were found in 26.7% strains from patients and one strain from C. apella. Strains from healthy subjects did not show any plasmid. Most of strains showed two plasmid bands ranging from 4 to 16 Kb, but digestions with endonucleases showed that they belonged to a single plasmid. The plasmid profile was similar and stable in human and monkey strains. Also, plasmids were classified into three groups according to size. Two strains were positive to beta-lactamase production and no plasmid DNA-hybridization with a beta-lactamase gene probe was observed, suggesting a chromosomal resistance.

The purpose of this study was to determine the prevalence of enteric bacteria and yeasts in biofilm of 80 HIV-positive patients with plaque-associated gingivitis or necrotizing periodontitis. Patients were subjected to extra, intra oral and radiographic examinations. The oral hygiene, bleeding on probing, gingival conditions, and attachment loss were evaluated. Clinical specimens were collected from gingival crevices or periodontal pockets, transferred to VMGA III, diluted and transferred to Sabouraud Dextrose agar with 100 μg/ml of chloramphenicol, peptone water, EVA broth, EMB agar, SS agar, Bile esculin agar and Brilliant green agar. Isolation of yeasts was carried out at room temperature, for 3-7 days; and for the isolation of enteric microorganisms plates were incubated at 37ºC, for 24-48 h. The yeasts identification was performed according to the carbon and nitrogen assimilation, fermentation of carbohydrates and germ tube formation. Bacteria were identified according to their colonial and cellular morphologies and biochemical tests. Yeasts were identified as Candida albicans and its occurrence was more common in patients with CD4+ below 200/mm 3 and was affected by the extension of periodontal involvement (P = 0.0345). Enteric bacteria recovered from clinical specimens were identified as Enterobacter sakazakii, Enterobacter cloacae, Serratia liquefaciens, Klebsiella oxytoca and Enterococcus sp. Enterobacteriaceae and enterococci were detected in 32.5% of clinical samples from patients with necrotizing periodontitis. In conclusion, non-oral pathogenic bacteria and C. albicans were more prevalent in periodontal sites of HIV-positive patients with necrotizing periodontitis and chronic gingivitis.