Maria Auxiliadora Roque de Carvalho

Federal University of Minas Gerais, Belo Horizonte, Estado de Minas Gerais, Brazil

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Publications (19)42.07 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Topical therapy is the first choice for the treatment of mild to moderate acne and all-trans retinoic acid is one of the most used drugs. The combination of retinoids and antimicrobials is an innovative approach for acne therapy. Recently, lauric acid, a saturated fatty acid, has shown strong antimicrobial activity against Propionibacterium acnes. However, topical application of retinoic acid is followed by high incidence of side-effects, including erythema and irritation. Solid lipid nanoparticles represent an alternative to overcome these side-effects. This work aims to develop solid lipid nanoparticles loaded with retinoic acid and lauric acid and evaluate their antibacterial activity. The influence of lipophilic stearylamine on the characteristics of solid lipid nanoparticles was investigated. Solid lipid nanoparticles were characterized for size, zeta potential, encapsulation efficiency, differential scanning calorimetry and X-ray diffraction. The in vitro inhibitory activity of retinoic acidlauric acid-loaded solid lipid nanoparticles was evaluated against Propionibacterium acnes, Staphylococcus aureus and Staphylococcus epidermidis. High encapsulation efficiency was obtained at initial time (94±7% and 100±4% for retinoic acid and lauric acid, respectively) and it was demonstrated that lauric acid-loaded-solid lipid nanoparticles provided the incorporation of retinoic acid. However, the presence of stearylamine is necessary to ensure stability of encapsulation. Moreover, retinoic acid-lauric acid-loaded solid lipid nanoparticles showed growth inhibitory activity against Staphylococcus epidermidis, Propionibacterium acnes and Staphylococcus aureus, representing an interesting alternative for the topical therapy of acne vulgaris.
    Journal of Nanoscience and Nanotechnology 01/2015; 15(1). · 1.15 Impact Factor
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    ABSTRACT: Bacteroides fragilis is the anaerobe most frequently isolated from clinical specimens and piperacillin/tazobactam is among the drugs that can be used to treat polymicrobial infections in which this bacteria is often involved. During antibiotic therapy, inhibitory concentrations of antibiotics are always followed by subinhibitory concentrations which can generate phenotypic changes in bacteria. So, in this study we aimed to evaluate changes in the proteomic profile of B. fragilis grown in a sub-MIC of PTZ, using 2-D electrophoresis followed by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight. Analysis of the 2-DE gels showed 18 spots with significantly different volume percentages between experimental conditions and 12 were successfully identified by MS/MS. Two proteins with decreased abundance in sub-MIC condition were involved in the glycolysis (glyceraldehyde 3-phosphate dehydrogenase and triosephosphate isomerase), others two involved in amino-acid metabolism (Oxoacyl-(acyl-carrier protein) synthase II and dihydrodipicolinate reductase), and finally, one protein involved in fatty acid metabolism (UDP-N-acetylglucosamine acyltransferase). Among the proteins with increased abundance, we founded three ATP synthase (alpha, beta, and alpha type V), which could be involved in antibiotic bacterial resistance by efflux pump, one protein involved in glycolysis (enolase), and one involved in protein degradation (aminoacyl-histidine dipeptidase). In conclusion, our data show overall changes in the proteome of B. fragilis conducted by sub-MIC of PTZ, whose consequences on bacterial physiology deserve further investigation.
    Anaerobe 04/2013; · 2.02 Impact Factor
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    ABSTRACT: Objectives: We aimed to evaluate the profile of hospitalized patients presenting with odontogenic infections requiring intensive care and to identify predictive factors of worsening of the disease. Study Design: In this retrospective study, 119 consecutive medical records were assessed for data regarding odontogenic infections. The variables examined were age, gender, etiology, time from onset of infection to hospital admission, hospital stay, complications during hospitalization, and anatomical sites affected. Results: Most patients were female (64.7%) and the mean age of our study group was 28.3 years. Average length of hospital stay was 7.3 ± 6.3 days and the mean time from onset of infection to hospitalization was 6.9 days. Lower teeth corresponded to the initially affected site in the great majority (72.3%) of the cases and the mandibular third molar was the most commonly first infected tooth (31.9%). Post-surgical infection was involved in 21.8% of the cases. Systemic conditions were reported for 18.5% of the patients, mainly hypertension, but they were not determinant for admission. The main reasons for hospitalization were dyslalia, dysphagia, and dyspnea, either as single or associated signs (96.6%). Antimicrobial therapy was administered alone or combined with surgical drainage to 64 (53.8%) and 53 (44.5%) patients, respectively. Conclusions: Overall data generated by this investigation on the profile of severe odontogenic infection patients in our region are similar to those reported by other researchers. Conversely we found a higher prevalence of the disease among women in disagreement with previously published results. Such a kind of study may improve our knowledge relative to the disease and also reveal the regional scenario regarding severe odontogenic infections. Consequently it may contribute to the designing of strategies that may lead to a more efficient oral health care system what ultimately would culminate with the prevention of more severe outcomes from the disease.
    Journal of Clinical and Experimental Dentistry. 11/2012; 4:e271- e274.
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    ABSTRACT: In Brazil, few studies on microbial content of dental solid waste and its antibiotic susceptibility are available. An effort has been made through this study to evaluate the hazardous status of dental solid waste, keeping in mind its possible role in cross-infection chain. Six samples of solid waste were collected at different times and seasons from three dental health services. The microbial content was evaluated in different culture media and atmospheric conditions, and the isolates were submitted to antibiotic susceptibility testing. A total of 766 bacterial strains were isolated and identified during the study period. Gram-positive cocci were the most frequent morphotype isolated (48.0%), followed by Gram-negative rods (46.2%), Gram-positive rods (5.0%), Gram-negative-cocci (0.4%), and Gram-positive coccobacillus (0.1%). Only two anaerobic bacteria were isolated (0.3%). The most frequently isolated species was Staphylococcus epidermidis (29.9%), followed by Stenotrophomonas maltophilia (8.2%), and Enterococcus faecalis (6.7%). High resistance rate to ampicillin was observed among Gram-negative rods (59.4%) and Gram-positive cocci (44.4%). For Gram-negative rods, high resistance was also noted to aztreonam (47.7%), cefotaxime (47.4%), ceftriaxone and cefazolin (43.7%), and ticarcillin-clavulanic acid (38.2%). Against Gram-positive cocci penicillin exhibit a higher resistance rate (45.0%), followed by ampicillin, erythromycin (27.2%), and tetracycline (22.0%). The present study demonstrated that several pathogenic bacteria are present in dental solid waste and can survive after 48 h from the waste generation time and harbor resistance profiles against several clinical recommended antibiotics.
    Waste Management 06/2011; 31(6):1327-32. · 3.16 Impact Factor
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    ABSTRACT: The elimination of microorganisms from root canals is a critical step in endodontic treatment. We aimed to evaluate the antimicrobial effectiveness of an alternating irrigation regimen during chemomechanical preparation (CMP). During 21 days, root canals of extracted human teeth were infected with Enterococcus faecalis, and colonization was confirmed by scanning electron microscopy (SEM). Canals were irrigated with saline solution (control group), with 5.25% NaOCl followed by a final rinse with 17% EDTA (conventional irrigation group), or with the alternating use of NaOCl and EDTA (alternating irrigation [AI] group). Samples were taken before treatment (S1), after CMP (S2), and during the following 14 days. Two specimens/group were analyzed by SEM. The AI group yielded negative agar and liquid cultures from immediately after CMP and from the 5th day on, respectively. SEM confirmed several bacterium-free sites in the AI group. The irrigation regimen based on the alternating use of NaOCl and EDTA seems to be a promising endodontic tool because it promoted the elimination of root canal E. faecalis biofilms throughout the experimental period.
    Journal of endodontics 05/2010; 36(5):894-8. · 2.95 Impact Factor
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    ABSTRACT: The worldwide emergence of antibiotic-resistant bacteria poses a serious threat to human health. In addition to the difficulties in controlling infectious diseases, the phenotype of resistance can generate metabolic changes which, in turn, can interfere with host-pathogen interactions. The aim of the present study was to identify changes in the subproteome of a laboratory-derived piperacillin/tazobactam-resistant strain of Escherichia coli (minimal inhibitory concentration [MIC] = 128 mg/L) as compared with its susceptible wild-type strain E. coli ATCC 25922 (MIC = 2 mg/L) using 2-D fluorescence difference gel electrophoresis (2D-DIGE) followed by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight (MALDI-TOF/TOF MS). In the resistant strain, a total of 12 protein species were increased in abundance relative to the wild-type strain, including those related to bacterial virulence, antibiotic resistance and DNA protection during stress. Fourteen proteins were increased in abundance in the wild-type strain compared to the resistant strain, including those involved in glycolysis, protein biosynthesis, pentose-phosphate shunt, amino acid transport, cell division and oxidative stress response. In conclusion, our data show overall changes in the subproteome of the piperacillin/tazobactam-resistant strain, reporting for the first time the potential role of a multidrug efflux pump system in E. coli resistance to piperacillin/tazobactam.
    Research in Microbiology 04/2010; 161(4):268-75. · 2.89 Impact Factor
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    ABSTRACT: When developing proper waste management strategies, it is essential to characterize the volume and composition of solid waste. The aim of this work was to evaluate the composition of dental waste produced by three dental health services in Belo Horizonte, Minas Gerais State, Brazil. Two universities, one public and one private, and one public dental health service were selected. Waste collection took place from March to November 2007. During this period, three samples were collected from each dental health service. The total amount of dental waste produced in one day of dental work was manually separated into three categories: infectious and potentially infectious waste, accounting for 24.3% of the total waste; non-infectious waste, accounting for 48.1%; and domestic-type waste, accounting for 27.6% (percentages are for mean weights of solid waste). Our results showed that most of the waste considered as biomedical may be misclassified, consequently making the infectious waste amount appear much larger. In addition, our results suggest that the best waste minimization method is recycling, and they help to define an appropriate waste management system in all three of the dental health services involved in this study.
    Waste Management 02/2009; 29(4):1388-91. · 3.16 Impact Factor
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    ABSTRACT: Aggregatibacter (Actinobacillus) actinomycetemcomitans P(7-20) strain isolated from a periodontally diseased patient has produced a bacteriocin (named as actinomycetemcomitin) that is active against Peptostreptococcus anaerobius ATCC 27337. Actinomycetemcomitin was produced during exponential and stationary growth phases, and its amount decreased until it disappeared during the decline growth phase. It was purified by ammonium sulphate precipitation (30-60% saturation), and further by FPLC (mono-Q ionic exchange and Phenyl Superose hydrophobic interaction) and HPLC (C-18 reversed-phase). This bacteriocin loses its activity after incubation at a pH below 7.0 or above 8.0, following heating for 30 min at 45 degrees C, and after treatment with proteolytic enzymes such as trypsin, alpha-chymotrypsin, and papain. Actinomycetemcomitin has a molecular mass of 20.3 KDa and it represents a new bacteriocin from A. actinomycetemcomitans.
    Journal of Industrial Microbiology and Biotechnology 03/2008; 35(2):103-10. · 2.32 Impact Factor
  • Journal of Medical Microbiology 12/2007; 56(Pt 11):1576-9. · 2.30 Impact Factor
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    ABSTRACT: Ertapenem and piperacillin/tazobactam are beta-lactam antibiotics with a broad spectrum of activity used for the treatment of mixed infections in which Bacteroides fragilis and Escherichia coli play an important aetiological role. In this study, the activities of piperacillin/tazobactam and ertapenem (MIC and time-kill kinetics) against these bacteria were compared. MICs were determined by the agar dilution method, and the time and slope of time-kill curves were analysed. In the in vitro pharmacodynamic assays, pure and mixed cultures of E. coli and B. fragilis were exposed to peak concentrations of ertapenem (8.0 microg ml(-1)) and piperacillin/tazobactam (64.0/8.0 microg ml(-1)) for 48 h. Treatment with ertapenem reduced the viability of E. coli and/or B. fragilis by 3 logs in all experiments, whereas piperacillin/tazobactam only affected the viability of B. fragilis. Both drugs exhibited their fastest rates of killing when bacteria were grown in mixed cultures. According to the results, ertapenem exhibited activity similar to that of piperacillin/tazobactam against B. fragilis alone or in mixed culture. However, ertapenem exhibited a markedly higher activity against E. coli alone or in combination with B. fragilis relative to piperacillin/tazobactam.
    Journal of Medical Microbiology 07/2007; 56(Pt 6):798-802. · 2.30 Impact Factor
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    Brazilian Journal of Microbiology 01/2007; 38(2). · 0.76 Impact Factor
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    ABSTRACT: Periodontitis is associated with members of the oral microbiota, such as Actinobacillus actinomycetemcomitans. To our knowledge, this is the first study to evaluate, by PCR, the occurrence of the six known bacterium serotypes that included subjects with and without periodontitis. Our group comprised 49 Brazilian subjects. We studied 146 bacterial isolates from 23 patients with aggressive or chronic periodontitis and 26 subgingival specimens from subjects with or without periodontitis, all originating in our collection. Serotypes b and c were observed in similar frequencies, and no subject harboured d, e, or f serotype strains. Around 78% subjects had single-serotype infection. Mixed infection was seen only in aggressive periodontitis patients. An association between serotype b and healthy periodontium and between serotype c and chronic periodontitis was observed. Our results diverge from those previously reported, which may be explained by specific distribution patterns in distinct populations. The association of different serotypes with the same periodontal status or conversely of a serotype with different periodontal conditions indicates that organism serotyping should not be used as a sole reliable marker for predicting the outcome of the infection. Evaluation of factors involved in human oral cavity colonization by subsets of A. actinomycetemcomitans is essential for elucidating organism-host-environment relationships.
    Canadian Journal of Microbiology 04/2006; 52(3):182-8. · 1.20 Impact Factor
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    ABSTRACT: As doenças periodontais resultam de resposta inflamatória progressiva do hospedeiro ao acúmulo de placa bacteriana, incluindo os metabólitos no dente e nos tecidos gengivais. Assim, avaliou-se, clinicamente, o periodonto de cães da raça Pastor Alemão, levando-se em consideração presença de tártaro, sangramento à sondagem e mobilidade dentária em animais com sítios saudáveis e com doença periodontal. Para isso, utilizaram-se 29 cães,da raça Pastor Alemão, com idade variando de três a seis anos. Clinicamente, 27 (93,10%) cães apresentavam vários sítios com sintomatologia clínica de doença periodontal e somente dois apresentavam sítios saudáveis. Os dentes mais acometidos foram os molares, os pré-molares e os caninos,com sinais clínicos mais intensos nas superfícies dentárias e maior acúmulo de tártaro e placa bacteriana. Os resultados demonstraram a necessidade de se proceder a uma limpeza preventiva dos dentes, para proporcionar maior saúde para os cães. PALAVRAS-CHAVE: Periodonto, cães, dente.
    Ciência Animal Brasileira. 01/2006;
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    ABSTRACT: A considerable number of tests are recommended in the literature to evaluate in vitro commercial chemical solutions. The variety of tests reflects their limitations and the need to enhance disinfection process. In this study the efficacy of 4 chemical disinfectants selected by their practical use in Health Care Services and by literature recommendation in aerobic and in strict anaerobic bacteria were evaluated by their practical use in Health Care Services and by literature recommendation in aerobic and in strict anaerobic bacteria. Viability was tested in biofilms grown on glass and rubber tip carriers. The results showed microbial growth in chemical solutions at concentrations recommended by the literature or at very close concentrations to them. Viable cells were recovered from biofilms after 30 minutes (Bacteroides fragilis) and 60 minutes (Streptococcus mutans and Salmonella tiphymurium) contact with 2.4% glutaraldehyde and after 60 minutes (S tiphymurium) in 2.0% glutaraldehyde. In 70% ethyl alcohol, S tiphymurium was viable up to 10 minutes, Escherichia coli up to 30 minutes, and S mutans up to 60 minutes. In 1% sodium hypochlorite, S mutans was viable up to 30 minutes and S tiphymurium up to 45 minutes. Detection of cell viability could be related to methodologic differences, including biofilm formation, as demonstrated by scanning electron microscopy. It should be emphasized that B fragilis, the most clinically relevant obligate anaerobe, remained viable in one routinely used solution. These findings pointed out the need of periodic surveillance of disinfectants' activity used in Health Care Services and the need of reviewing routines of disinfection protocols.
    American Journal of Infection Control 05/2005; 33(3):162-9. · 2.73 Impact Factor
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    ABSTRACT: We evaluated antimicrobial susceptibility patterns of microorganisms isolated from intraabdominal infection of Brazilian patients, by agar dilution, agar diffusion, and E test. Among the strictly anaerobes, 57.7% were resistant to penicillin, 28.2% to clindamycin, and 9.9% to metronidazole. The majority of Escherichia coli and Staphylococcus were sensitive and resistant to almost all drugs, respectively. Half of Candida samples were resistant to itraconazole. Our data reinforce the importance of this kind of study to support rational antimicrobial therapy.
    American Journal of Infection Control 12/2004; 32(7):414-6. · 2.73 Impact Factor
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    ABSTRACT: Several studies indicate Actinobacillus (Haemophilus) actinomycetemcomitans and Fusobacterium nucleatum as etiologic agents of periodontal disease. Immunosuppressive factors produced by microorganisms probably contribute to the initiation and evolution of this disease. This study evaluated the antiproliferative activity of ammonium precipitate fractions of A. (H.) actinomycetemcomitans and F. nucleatum isolates from humans and marmosets both with and without periodontal disease. All A. (H.) actinomycetemcomitans and most F. nucleatum strains inhibited PBMC proliferation in a dose-dependent manner. The degree of cell proliferative inhibition of each bacterial species differed among the strains and was independent of host clinical status. The in vitro inhibition of stimulated lymphocyte proliferation induced by different A. (H.) actinomycetemcomitans and F. nucleatum isolates demonstrated the importance of this phenomenon in bacterial virulence, playing a possible suppressor role in host defense mechanisms in vivo. Moreover, our findings pointed out a marked difference between A. (H.) actinomycetemcomitans and F. nucleatum cytoplasmic extracts in their antiproliferative activity, regarding the antigen concentration required for maximum inhibition and their vulnerability to heating and proteolytic treatment.
    Research in Microbiology 12/2004; 155(9):731-40. · 2.89 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate the influence of the infecting dose on bacterial colonization in root canal systems (RCS) and translocation to the submandibular lymph node (SML) of gnotobiotic (germ-free) mice. RCS were inoculated with 10(2) and 10(1) colony-forming units (CFU) of Enterococcus faecalis (ATCC 4083) or 10(5), 10(4), 10(3), and 10(2) CFU of Prevotella nigrescens (ATCC 33563). E. faecalis implanted in 83.3% of the cases, for both inocula. Translocation was detected in 58.3% of lymph nodes for the 10(2) CFU inoculum and in 33.3% of lymph nodes for the 10(1) CFU inoculum. P. nigrescens implanted in 25%, 16.7%, 8.3%, and 0%, for the 10(5), 10(4), 10(3), and 10(2) CFU inocula, respectively, and did not translocate at any of the concentrations used. These results indicate that E. faecalis was able to implant in the RCS and translocate to the SML, whereas P. nigrescens implanted in lower percentages in the RCS and did not translocate to the SML.
    Journal of Endodontics 02/2003; 29(1):24-7. · 2.93 Impact Factor
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    ABSTRACT: Metronidazole is widely used to treat protozoan and fungal infections. As an antibacterial drug, it is used mainly against anaerobes. Among anaerobes, the Bacteroides fragilis group is the most relevant in terms of frequency of recovery and antimicrobial resistance patterns. The use of metronidazole and other antimicrobial drugs induces morphological changes in this bacterial group. The present study investigated in vivo if these morphological modifications were accompanied by changes in virulence patterns by using germfree mice experimentally challenged with metronidazole-resistant Bacteroides strains before and after exposure to metronidazole. It was observed that metronidazole-resistant strains were more virulent after contact with the drug, as demonstrated by anatomicopathologic data for spleen, liver, and small intestine samples. These results suggest that long-term therapy and high metronidazole concentrations could interfere with microbial pathogenicity, resulting in changes to host-bacterium relationships.
    Antimicrobial Agents and Chemotherapy 10/2000; · 4.57 Impact Factor
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    Anaerobe 01/1999; 5(3):157-159. · 2.02 Impact Factor

Publication Stats

65 Citations
42.07 Total Impact Points


  • 1999–2013
    • Federal University of Minas Gerais
      • • Departamento de Microbiologia
      • • Instituto de Cîências Biológicas (ICB)
      Belo Horizonte, Estado de Minas Gerais, Brazil
  • 2010
    • Universidade Federal dos Vales do Jequitinhonha e Mucuri
      Tejuco, Minas Gerais, Brazil
  • 2008
    • Federal University of Rio de Janeiro
      • Instituto de Microbiologia Professor Paulo de Góes (IMPPG)
      Rio de Janeiro, Rio de Janeiro, Brazil
  • 2004
    • Universidade Vale do Rio Doce
      Figueira, Minas Gerais, Brazil