Bloodstream and catheter-related infections due to different clones of multidrug-resistant and biofilm producer Corynebacterium striatum.

BACKGROUND: Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen associated with immunocompromised and chronically ill patients, as well as nosocomial outbreaks. In this study, we characterized 23 MDR C. striatum isolated of bloodstream and catheter-related infections from a hospital of Rio de Janeiro. METHODS: C. striatum isolates were identified by 16S rRNA and rpoB genes sequencing. The dissemination of these isolates was accomplished by pulsed-field gel electrophoresis (PFGE). All isolates were submitted to antimicrobial susceptibility testing by disk diffusion and by minimum inhibitory concentration using E-test strips methods. Antimicrobial resistance genes were detected by polymerase chain reaction. Quantitative tests were performed on four different abiotic surfaces and the ability to produce biofilm on the surface of polyurethane and silicone catheter was also demonstrated by scanning electron microscopy. RESULTS: Eleven PFGE profiles were found. The PFGE profile I was the most frequently observed among isolates. Five different MDR profiles were found and all PFGE profile I isolates presented susceptibility only to tetracycline, vancomycin, linezolid and daptomycin. Only the multidrug-susceptible isolate did not show mutations in the quinolone-resistance determinant region (QRDR) of the gyrA gene and was negative in the search of genes encoding antibiotic resistance. The other 22 isolates were positive to resistance genes to aminoglycoside, macrolides/lincosamides and chloramphenicol and showed mutations in the QRDR of the gyrA gene. Scanning electron microscopy illustrated the ability of MDR blood isolate partaker of the epidemic clone (PFGE profile I) to produce mature biofilm on the surface of polyurethane and silicone catheter. CONCLUSIONS: Genotyping analysis by PFGE revealed the permanence of the MDR PFGE profile I in the nosocomial environment. Other new PFGE profiles emerged as etiologic agents of invasive infections. However, the MDR PFGE profile I was also found predominant among patients with hematogenic infections. The high level of multidrug resistance associated with biofilm formation capacity observed in MDR C. striatum is a case of concern.

Evaluation of polymethyl methacrylate containing chlorhexidine: A randomized, controlled, split-mouth in situ study.

PURPOSE: To evaluate the antimicrobial action and elemental composition of chlorhexidine (CHX) diacetate in acrylic resins based on PMMA (polymethyl methacrylate) in situ. In addition, ex vivo evaluation of the CHX release mechanism was performed over a 14-day period. METHODS: Three discs of PMMA incorporating CHX and three control discs were mounted on individual oral splints and exposed to the oral cavity of 32 participants for 24 hours. The antimicrobial activity was evaluated by the plate count method. In the second test, elemental analysis of the specimens (n = 10) was performed by X-ray fluorescence before and after use of the device. Chlorhexidine release over a 14-day period was evaluated ex vivo in saliva samples collected from five individuals through proton nuclear magnetic resonance spectroscopy ( ¹H NMR) (500 MHz). RESULTS: Bacterial adhesion, evaluated by the plate count method, did not differ between the experimental material and control. (P> 0.05) The presence of the CHX molecule was detected by X-ray fluorescence before and after insertion of discs containing CHX into the oral cavity of participants. With regard to release, CHX was detected in saliva samples for 14 days and highest during the first 24 hours. When partial least squares discriminant analysis (PLS-DA) was applied in ¹H NMR, we observed a greater difference between the test and control groups. CLINICAL SIGNIFICANCE: The sustained release of CHX from PMMA suggests that such materials may be convenient for reducing the development of biofilm on the surface of the material for use in dentures and temporary restorative materials.

Genome sequence of a multidrug-resistant Corynebacterium striatum isolated from bloodstream infection from a nosocomial outbreak in Rio de Janeiro, Brazil.

Multidrug-resistant (MDR) Corynebacterium striatum has been cited with increased frequency as pathogen of nosocomial infections. In this study, we report the draft genome of a C. striatum isolated from a patient with bloodstream infection in a hospital of Rio de Janeiro, Brazil. The isolate presented susceptibility only to tetracycline, vancomycin and linezolid. The detection of various antibiotic resistance genes is fully consistent with previously observed multidrug-resistant pattern in Corynebacterium spp. A large part of the pTP10 plasmid of MDR C. striatum M82B is present in the genome of our isolate. A SpaDEF cluster and seven arrays of CRISPR-Cas were found.

Tellurite resistance: a putative pitfall in Corynebacterium diphtheriae diagnosis?

Corynebacterium diphtheriae strains continue to circulate worldwide causing diphtheria and invasive diseases, such as endocarditis, osteomyelitis, pneumonia and catheter-related infections. Presumptive C. diphtheriae infections diagnosis in a clinical microbiology laboratory requires a primary isolation consisting of a bacterial culture on blood agar and agar containing tellurite (TeO3(2-)). In this study, nine genome sequenced and four unsequenced strains of C. diphtheriae from different sources, including three samples from a recent outbreak in Brazil, were characterized with respect to their growth properties on tellurite-containing agar. Levels of tellurite-resistance (Te(R)) were evaluated by determining the minimum inhibitory concentrations of potassium tellurite (K2TeO3) and by a viability reduction test in solid culture medium with K2TeO3. Significant differences in Te(R) levels of C. diphtheriae strains were observed independent of origin, biovar or presence of the tox gene. Data indicated that the standard initial screening with TeO3(2-)-selective medium for diphtheria bacilli identification may lead to false-negative results in C. diphtheriae diagnosis laboratories.

Biofilm formation and fibrinogen and fibronectin binding activities by Corynebacterium pseudodiphtheriticum invasive strains.

Biofilm-related infections are considered a major cause of morbidity and mortality in hospital environments. Biofilms allow microorganisms to exchange genetic material and to become persistent colonizers and/or multiresistant to antibiotics. Corynebacterium pseudodiphtheriticum (CPS), a commensal bacterium that colonizes skin and mucosal sites has become progressively multiresistant and responsible for severe nosocomial infections. However, virulence factors of this emergent pathogen remain unclear. Herein, we report the adhesive properties and biofilm formation on hydrophilic (glass) and hydrophobic (plastic) abiotic surfaces by CPS strains isolated from patients with localized (ATCC10700/Pharyngitis) and systemic (HHC1507/Bacteremia) infections. Adherence to polystyrene attributed to hydrophobic interactions between bacterial cells and this negatively charged surface indicated the involvement of cell surface hydrophobicity in the initial stage of biofilm formation. Attached microorganisms multiplied and formed microcolonies that accumulated as multilayered cell clusters, a step that involved intercellular adhesion and synthesis of extracellular matrix molecules. Further growth led to the formation of dense bacterial aggregates embedded in the exopolymeric matrix surrounded by voids, typical of mature biofilms. Data also showed CPS recognizing human fibrinogen (Fbg) and fibronectin (Fn) and involvement of these sera components in formation of "conditioning films". These findings suggested that biofilm formation may be associated with the expression of different adhesins. CPS may form biofilms in vivo possibly by an adherent biofilm mode of growth in vitro currently demonstrated on hydrophilic and hydrophobic abiotic surfaces. The affinity to Fbg and Fn and the biofilm-forming ability may contribute to the establishment and dissemination of infection caused by CPS.

Biofilm production by multiresistant Corynebacterium striatum associated with nosocomial outbreak.

Corynebacterium striatum is a potentially pathogenic microorganism that causes nosocomial outbreaks. However, little is known about its virulence factors that may contribute to healthcare-associated infections (HAIs). We investigated the biofilm production on abiotic surfaces of multidrug-resistant (MDR) and multidrug-susceptible (MDS) strains of C. striatum of pulsed-field gel electrophoresis types I-MDR, II-MDR, III-MDS and IV-MDS isolated during a nosocomial outbreak in Rio de Janeiro, Brazil. The results showed that C. striatum was able to adhere to hydrophilic and hydrophobic abiotic surfaces. The C. striatum 1987/I-MDR strain, predominantly isolated from patients undergoing endotracheal intubation procedures, showed the greatest ability to adhere to all surfaces. C. striatum bound fibrinogen to its surface, which contributed to biofilm formation. Scanning electron microscopy showed the production of mature biofilms on polyurethane catheters by all pulsotypes. In conclusion, biofilm production may contribute to the establishment of HAIs caused by C. striatum.

Corynebacterium diphtheriae putative tellurite-resistance protein (CDCE8392_0813) contributes to the intracellular survival in human epithelial cells and lethality of Caenorhabditis elegans.

Corynebacterium diphtheriae, the aetiologic agent of diphtheria, also represents a global medical challenge because of the existence of invasive strains as causative agents of systemic infections. Although tellurite (TeO32-) is toxic to most microorganisms, TeO32--resistant bacteria, including C. diphtheriae, exist in nature. The presence of TeO32--resistance (TeR) determinants in pathogenic bacteria might provide selective advantages in the natural environment. In the present study, we investigated the role of the putative TeR determinant (CDCE8392_813gene) in the virulence attributes of diphtheria bacilli. The disruption of CDCE8392_0813 gene expression in the LDCIC-L1 mutant increased susceptibility to TeO32- and reactive oxygen species (hydrogen peroxide), but not to other antimicrobial agents. The LDCIC-L1 mutant also showed a decrease in both the lethality of Caenorhabditis elegans and the survival inside of human epithelial cells compared to wild-type strain. Conversely, the haemagglutinating activity and adherence to and formation of biofilms on different abiotic surfaces were not regulated through the CDCE8392_0813 gene. In conclusion, the CDCE8392_813 gene contributes to the TeR and pathogenic potential of C. diphtheriae.

Evaluation of two disinfection/sterilization methods on silicon rubber-based composite finishing instruments.

PURPOSE: To evaluate the effectiveness of disinfection/sterilization methods and their effects on polishing capacity, micomorphology, and composition of two different composite fiishing and polishing instruments. METHODS: Two brands of finishing and polishing instruments (Jiffy and Optimize), were analyzed. For the antimicrobial test, 60 points (30 of each brand) were used for polishing composite restorations and submitted to three different groups of disinfection/sterilization methods: none (control), autoclaving, and immersion in peracetic acid for 60 minutes. The in vitro tests were performed to evaluate the polishing performance on resin composite disks (Amelogen) using a 3D scanner (Talyscan) and to evaluate the effects on the points' surface composition (XRF) and micromorphology (MEV) after completing a polishing and sterilizing routine five times. RESULTS: Both sterilization/disinfection methods were efficient against oral cultivable organisms and no deleterious modification was observed to point surface.

Clonal multidrug-resistant Corynebacterium striatum within a nosocomial environment, Rio de Janeiro, Brazil.

Corynebacterium striatum is a potentially pathogenic microorganism with the ability to produce outbreaks of nosocomial infections. Here, we document a nosocomial outbreak caused by multidrug-resistant (MDR) C. striatum in Rio de Janeiro, Brazil. C. striatum identification was confirmed by 16S rRNA and rpoB gene sequencing. Fifteen C. striatum strains were isolated from adults (half of whom were 50 years of age and older). C. striatum was mostly isolated in pure culture from tracheal aspirates of patients undergoing endotracheal intubation procedures. The analysis by pulsed-field gel electrophoresis (PFGE) indicated the presence of four PFGE profiles, including two related clones of MDR strains (PFGE I and II). The data demonstrated the predominance of PFGE type I, comprising 11 MDR isolates that were mostly isolated from intensive care units and surgical wards. A potential causal link between death and MDR C. striatum (PFGE types I and II) infection was observed in five cases.

Corynebacterium diphtheriae 67-72p hemagglutinin, characterized as the protein DIP0733, contributes to invasion and induction of apoptosis in HEp-2 cells.

Although Corynebacterium diphtheriae has been classically described as an exclusively extracellular pathogen, there is growing evidence that it may be internalized by epithelial cells. The aim of the present report was to investigate the nature and involvement of the surface-exposed non-fimbrial 67-72 kDa proteins (67-72p), previously characterized as adhesin/hemagglutinin, in C. diphtheriae internalization by HEp-2 cells. Transmission electron microscopy and bacterial internalization inhibition assays indicated the role of 67-72p as invasin for strains of varied sources. Cytoskeletal changes with accumulation of polymerized actin in HEp-2 cells beneath adherent 67-72p-adsorbed microspheres were observed by the Fluorescent actin staining test. Trypan blue staining method and Methylthiazole tetrazolium reduction assay showed a significant decrease in viability of HEp-2 cells treated with 67-72p. Morphological changes in HEp-2 cells observed after treatment with 67-72p included vacuolization, nuclear fragmentation and the formation of apoptotic bodies. Flow cytometry revealed an apoptotic volume decrease in HEp-2 cells treated with 67-72p. Moreover, a double-staining assay using Propidium Iodide/Annexin V gave information about the numbers of vital vs. early apoptotic cells and late apoptotic or secondary necrotic cells. The comparative analysis of MALDI-TOF MS experiments with the probes provided for 67-72p CDC-E8392 with an in silico proteome deduced from the complete genome sequence of C. diphtheriae identified with significant scores 67-72p as the protein DIP0733. In conclusion, DIP0733 (67-72p) may be directly implicated in bacterial invasion and apoptosis of epithelial cells in the early stages of diphtheria and C. diphtheriae invasive infection.

The role of DNA base excision repair in filamentation in Escherichia coli K-12 adhered to epithelial HEp-2 cells.

Base excision repair (BER) is dedicated to the repair of oxidative DNA damage caused by reactive oxygen species generated by chemical and physical agents or by metabolism which can react with DNA and cause a variety of mutations. Epithelial cells are typically the first type of host cell to come into contact with potential microbial invaders. In this work, we have evaluated whether the adherence to human epithelial cells causes DNA damage and associated filamentation. Experiments concerning adherence to HEp-2 cells were carried out with mutants deficient in BER that were derived from Escherichia coli K-12. Since the removal of mannose during bacterial interaction with HEp-2 cells allows adhesion through mannose-sensitive adhesins, the experiments were also performed in the presence and the absence of mannose. Our results showed enhanced filamentation for the single xth (BW9091) and triple xth nfo nth (BW535) mutants in adherence assays with HEp-2 cells performed without D: -mannose. The increased filamentation growth was inhibited by complementation of BER mutants with a wild type xth gene. Moreover, we measured SOS induction of bacteria adhered to HEp-2 cells in the presence and absence of D: -mannose through of SOS-chromotest assay and we observed a higher ß-galactosidase expression in the absence of mannose. In this context, data showed evidence that bacterial attachment to HEp-2 epithelial surfaces can generate DNA lesions and SOS induction.

Aggregative adherent strains of Corynebacterium pseudodiphtheriticum enter and survive within HEp-2 epithelial cells.

Corynebacterium pseudodiphtheriticum is a well-known human pathogen that mainly causes respiratory disease and is associated with high mortality in compromised hosts. Little is known about the virulence factors and pathogenesis of C. pseudodiphtheriticum. In this study, cultured human epithelial (HEp-2) cells were used to analyse the adherence pattern, internalisation and intracellular survival of the ATCC 10700 type strain and two additional clinical isolates. These microorganisms exhibited an aggregative adherence-like pattern to HEp-2 cells characterised by clumps of bacteria with a "stacked-brick" appearance. The differences in the ability of these microorganisms to invade and survive within HEp-2 cells and replicate in the extracellular environment up to 24 h post infection were evaluated. The fluorescent actin staining test demonstrated that actin polymerisation is involved in the internalisation of the C. pseudodiphtheriticum strains. The depolymerisation of microfilaments by cytochalasin E significantly reduced the internalisation of C. pseudodiphtheriticum by HEp-2 cells. Bacterial internalisation and cytoskeletal rearrangement seemed to be partially triggered by the activation of tyrosine kinase activity. Although C. pseudodiphtheriticum strains did not demonstrate an ability to replicate intracellularly, HEp-2 cells were unable to fully clear the pathogen within 24 h. These characteristics may explain how some C. pseudodiphtheriticum strains cause severe infection in human patients.

Fibrinogen binds to nontoxigenic and toxigenic Corynebacterium diphtheriae strains.

The production of fibrinous exudates may play an important role in determining the outcome of bacterial infection. Although pseudomembrane formation is a characteristic feature of diphtheria, little is known about the fibrinogen (Fbn)-binding properties of Corynebacterium diphtheriae strains and the influence of the gene that codes for diphtheria toxin (tox gene) in this process. In this study we demonstrated the ability of C. diphtheriae strains to bind to Fbn and to convert Fbn to fibrin. Bacterial interaction with rabbit plasma was evaluated by both slide and tube tests. Interaction of microorganisms with human Fbn was evaluated by both enzyme linked immunosorbent assay (ELISA) and fluorescein isothiocyanate-conjugated (FITC) Fbn binding assays. Nontoxigenic and toxigenic strains formed bacterial aggregates in the presence of plasma in the slide tests. The ability to convert Fbn to a loose web of fibrin in the plasma solution in the tube tests appeared to be a common characteristic of the species, including strains that do not carry the tox gene. Fbn binding to C. diphtheriae strains occurred at varying intensities, as demonstrated by the FITC-Fbn and ELISA binding assays. Our data suggest that the capacity to bind to Fbn and to convert Fbn to fibrin may play a role in pseudomembrane formation and act as virulence determinants of both nontoxigenic and toxigenic strains.

Self-cured resin modified by quaternary ammonium methacrylates and chlorhexidine: Cytotoxicity, antimicrobial, physical, and mechanical properties.

OBJECTIVE: To evaluate the addition of dimethylaminohexadecyl methacrylate (DMAHDM) and chlorhexidine diacetate on cytotoxicity, antimicrobial activity, physical, and mechanical properties of a self-cured resin. METHODS: 132 disk-shaped and 48 rectangular specimens were divided into four experimental groups as described: Control Group (CG - no addition), dCHX (1%), DMAHDM (5%), and DMAHDM+dCHX (5%+1%). The biofilm viability, flexural strength (FS - ISO 20795-1:2013), surface roughness (SR), and color stability (ΔE) were analyzed after being stored for 4 weeks in distilled water and immersed for 72h in coffee. Cytotoxicity was measured after 24h, 3, and 7 days of elution using an MTT test on L929 cells (ISO 10993-5:2009). SR and ΔE were measured by a contact profilometer and a spectrophotometer using the CIELab parameter. Data were submitted to ANOVA and Bonferroni's/Tukey's tests (p≤0.05). RESULTS: Significant antimicrobial activity against Streptococcus mutans and Candida albicans was detected in all groups when compared to the CG (p<0.05). Only the dCHX group, in 24h of elution, demonstrated no cytotoxicity effects. There was a statistical difference for FS on the tested groups (p<0.05). No differences were detected in the initial roughness' measurements among the groups (p>0.05). However, after storage and immersion in coffee, the groups containing DMAHDM presented with rougher surfaces and significantly lower color stability compared to the control (p<0.05). SIGNIFICANCE: The addition of dCHX and DMAHDM in self-cured resin presented antimicrobial properties; however, cytotoxicity, physical, and mechanical properties were compromised.

Epidemiological and clinical profile of infective endocarditis at a Brazilian tertiary care center: an eight-year prospective study.

INTRODUCTION: Infective endocarditis (IE) is a systemic infectious disease requiring a multidisciplinary team for treatment. This study presents the epidemiological and clinical data of 73 cases of IE in Rio de Janeiro, Brazil. METHODS: This observational prospective cohort study of endocarditis patients during an eight-year study period described 73 episodes of IE in 70 patients (three had IE twice). Community-associated (CAIE) and healthcare-acquired infective endocarditis (HAIE) were diagnosed according to the modified Duke criteria. The collected data included demographic, epidemiologic, and clinical characteristics, including results of blood cultures, echocardiographic findings, surgical interventions, and outcome. RESULTS: Analysis of data from the eight-year study period and 73 cases (70 patients) of IE showed a mean age of 46 years (SD=2.5 years; 1-84 years) and that 65.7% were male patients. The prevalence of CAIE and HAIE was 32.9% and 67.1%, respectively. Staphylococcus aureus (30.1%), Enterococcus spp. (19.1%), and Streptococcus spp. (15.0%) were the prevalent microorganisms. The relevant signals and symptoms were fever (97.2%; mean 38.6 + 0.05°C) and heart murmur (87.6%). Vegetations were observed in the mitral (41.1%) and aortic (27.4%) valves. The mortality rate of the cases was 47.9%. CONCLUSIONS: In multivariate analysis, chronic renal failure (relative risk [RR]= 1.60; 95% confidence interval [CI] 1.01-2.55), septic shock (RR= 2.19; 95% CI 1.499-3.22), and age over 60 years (RR= 2.28; 95% CI 1.44-3.59) were indirectly associated with in-hospital mortality. The best prognosis was related to the performance of cardiovascular surgery (hazard ratio [HR]= 0.51; 95% CI 0.26-0.99).

Antimicrobial resistance among Brazilian Corynebacterium diphtheriae strains.

The increasing problems with multidrug resistance in relation to Corynebacterium, including C. diphtheriae, are examples of challenges confronting many countries. For this reason, Brazilian C. diphtheriae strains were evaluated by the E-Test for their susceptibility to nine antibacterial drugs used in therapy. Resistance (MIC < 0.002; 0.38 microg/ml) to penicillin G was found in 14.8% of the strains tested. Although erythromycin (MIC90 0.75 microg/ml) and azithromycin (MIC90 0.064 microg/ml) were active against C. diphtheriae in this study, 4.2% of the strains showed decreased susceptibility (MIC 1.0 microg/ml) to erythromycin. Multiple resistance profiles were determined by the disk diffusion method using 31 antibiotics. Most C. diphtheriae strains (95.74%) showed resistance to mupirocin, aztreonam, ceftazidime, and/or oxacillin, ampicillin, penicillin, tetracycline, clindamycin, lincomycin, and erythromycin. This study presents the antimicrobial susceptibility profiles of Brazilian C. diphtheriae isolates. The data are of value to practitioners, and suggest that some concern exists regarding the use of penicillin.

Endocarditis due to Rhodotorula mucilaginosa in a kidney transplanted patient: case report and review of medical literature.

Introduction. Endocarditis caused by yeasts is currently an emerging cause of infective endocarditis and, when accompanied byfever of unknown origin, is more severe since interferes with proper diagnosis and endocarditis treatment. Case presentation. The Rio de Janeiro Infective Endocarditis Study Group reports a case of infectious endocarditis (IE) with negative blood cultures in a 45-year-old white female resident in Rio de Janeiro, Brazil, previously submitted to kidney transplantation. After diagnosis and intervention, the valve culture revealed Rhodotorula mucilaginosa. The clinical aspects and overview of endocarditis caused by Rhodotorula spp. demonstrated that R. muscilaginosa have been isolated from the last IE cases from kidney transplanted patients. Conclusion. Though most of the patients (in literature) recovered well from endocarditis caused by Rhodotorula spp., physicians must be aware for diagnosis of fungemia and fungal treatment in kidney transplanted patients suffering of fever of unknown origin in the modern immunosuppressive treatment.

Biofilms formed by Mycobacterium Abscessus Subsp. Bolletii in the presence of Subinhibitory concentrations of Glutaraldehyde - A Public Health issue / Biofilmes formados por Mycobacterium Abscessus Subsp. Bolletii na presença de concentrações subinibitórias de Glutaraldeído - um problema de Saúde Pública

Em 2008, a Agência Nacional de Vigilância Sanitária (Anvisa) divulgou uma nota técnica, informando, que de 2003 até 2008, haviam sido notificados mais de 2.000 casos de infecções hospitalares por Micobactérias de Crescimento Rápido em hospitais particulares do país, relacionados principalmente a procedimentos videolaparoscópicos. Um fator comum foi a predominância de um determinado clone de Mycobacterium abscessus subsp. bolletii, que acometeu principalmente a pele e o tecido celular subcutâneo dos pacientes. Após esses surtos, várias medidas foram tomadas pela Anvisa, entre elas, a suspensão da esterilização química por imersão de instrumental cirúrgico em qualquer agente esterilizante líquido. As investigações concluíram que os surtos se deviam a falhas no reprocessamento de equipamentos médicos críticos, que eram esterilizados principalmente pelo uso de glutaraldeído a 2%. Essas decisões se basearam em observações empíricas, pautadas exclusivamente na observação do que estava ocorrendo na prática hospitalar. Até hoje não foi elucidada a relação de M. abscessus subsp. bolletii e a sua alta tolerância ao glutaraldeído. Este estudo teve como objetivo avaliar a formação de biofilme de M. abscessus subsp. bolletii, de um surto epidêmico no Brasil, e M. abscessus subsp. abscessus, uma cepa de referência, em diferentes concentrações de glutaraldeído. Metodologia: Os biofilmes foram desenvolvidos em discos de policarbonato e aço inoxidável para análise de unidades formadoras de colônias e placas de cultura de células para análise em microscopia confocal de varredura a laser (CLSM). Resultados: Os resultados da análise comparativa da formação de biofilme por M. abscessus subsp. bolletii demonstrou que o microrganismo foi capaz de formar biofilme em ambos os tipos de disco, mesmo em altas concentrações de glutaraldeído. Houve redução na formação de biofilme quando exposto às concentrações de 1,0% e 1,5% de glutaraldeído, sem ser destruído. M. abscessus subsp. abscessus também foi capaz de formar biofilme em ambos os tipos de disco, mas o biofilme foi destruído nas concentrações de glutaraldeído de 1,0% e 1,5%. As duas cepas analisadas por CLSM desenvolveram biofilme após 7 e 14 dias de incubação. Também foi observada a presença de células viáveis no biofilme, mesmo após 14 dias de crescimento, na presença de altas concentrações de glutaraldeído. Conclusões - Esses resultados confirmaram a capacidade da espécie M. abscessus de sobreviver e se desenvolver em glutaraldeído e podem estar relacionados à ocorrência dos surtos. Esperamos que os dados obtidos com a realização deste trabalho possam contribuir de maneira efetiva no controle e prevenção dessas infecções, por ser uma questão séria de saúde pública nacional.

Involvement of intercellular adhesion molecule-1 and beta1 integrin in the internalization process to human endothelial cells of group B Streptococcus clinical isolates.

The mechanism by which group B Streptococcus (GBS) interacts with human cells and disrupts physiological processes is an intriguing area of investigation and continues to unfold. The aim of this study was to investigate the adherence and intracellular viability within endothelial ECV304 cells of GBS serotypes Ia, III and V isolates from patients and asymptomatic carriers. The GBS isolates from patients (GBS-Ia 90222-urine, GBS-III 90356-liquor and GBS-V 90186-blood strains) exhibited a more efficient adherence and survival mechanisms to endothelial cells than those from asymptomatic carriers (GBS-Ia 85147-oropharynx, GBS-III 80340 and GBS-V 88641-vagina strains), independent of bacterial serotypes. Treatment of endothelial ECV304 cells with EDTA demonstrated that Ca2+-dependent molecules modulated the adherence and internalization process of GBS-Ia and III to ECV304 cells. SDS-PAGE analysis of samples of biotinylated ECV304 extracts treated with GBS clinical isolates (urine 90222-Ia, liquor 90356-III and blood 90186-V strains) revealed fragments ranging from approximately 61 to approximately 179 kDa. Results of immunoassays with ECV304 membrane proteins showed that ICAM-1 molecules interacted only with GBS-III liquor 90356 strain while beta1 integrin interacted with GBS-III liquor 90356 and GBS-V blood 90186 invasive strains. Thus, the interaction between ICAM-1 and beta1-integrin seems an additional means by which GBS exploits host endothelial cells during infection. These findings add to the current understanding of the roles played by multiple receptor-ligand systems in the uptake and pathogenesis of GBS infection.

Efficacy of chemomechanical caries removal in reducing cariogenic microbiota: a randomized clinical trial.

The aim of this study was to compare the efficacy of chemochemical methods (Carisolv™ and Papacárie®) versus the manual method (excavators) in reducing the cariogenic microbiota in dentine caries of primary teeth. Forty-six healthy children (5 to 9 years old) having at least one primary tooth with a cavitated dentine carious lesion were included in the study. The teeth presented no clinical or radiographic signs of pulpal involvement. The sample of 74 teeth was randomly divided into three different groups: Papacárie® (n = 25), Carisolv™ (n = 27) and Manual (n = 22). Samples of carious and sound dentine were collected with sterile excavators before and after caries removal in the three groups. The dentine samples were transferred to glass tubes containing a 1mL thioglycollate medium used as a carrier and enriched for microbiological detection of mutans streptococci and Lactobacillus spp, after incubation for 6h at room temperature. The minimum detection value for colony forming units (CFU) was 3.3 x 102 CFU/ml, and the results were converted into scores from 0 to 4. A significant difference was observed in relation to the microbiological scores before and after caries removal for all methods (Wilcoxon test; p < 0.001). The use of chemomechanical methods for caries removal did not improve the reduction of cariogenic microorganisms in dentine caries lesions, in comparison with manual excavation.