Frequency and expression of genes involved in adhesion and biofilm formation in Staphylococcus aureus strains isolated from periodontal lesions.

BACKGROUND/PURPOSE: The aim of this study was to characterize the Staphylococcus aureus strains isolated from periodontal lesions of patients, to determine the expression of genes involved in cell adhesion upon their infection of human epithelial cells using an in vitro model, its biofilm formation, and its resistance to antibiotics. METHODS: S. aureus was analysed by PCR, Kirby-Bauer, and pulsed-field gel electrophoresis (PFGE), measuring gene expression by real-time PCR after infection of human cells in vitro. RESULTS: S. aureus was identified in 18.6% (50/268) of the samples. All strains (n = 50) possessed the virulence genes spa (Staphylococcal protein A), coa (coagulase), and icaAB (intercellular adhesin); 96% (n = 48) possessed clfB (clumping factor B), and 88% (n = 44) possessed ebps (elastin-binding protein) and sdrD (serine aspartate repeat protein D). All strains were resistant to methicillin, ampicillin, dicloxacillin, cefotaxime, and penicillin, and were multidrug resistant to 6-12 antibiotics. PFGE analysis showed 37 different pulsed-field types and most strains (60.4%) had a unique pulsed-field type. Twenty-four distinct combinations of virulence genes and antibiotic-resistant phenotypes were identified. CONCLUSION: Although S. aureus has been considered a transient member of the oral microbiota, our results indicate a high-level expression of virulence genes and multidrug resistance in the strains isolated from periodontal lesions. These strains might complicate the successful treatment of the disease.

Cytotoxic Activity of Cu/TiO2 Nanoparticles on Uterine-Cervical Cancer Cells.

Nanoparticles based on metal oxides serve as carrier matrices for molecules of biological interest. In this work, we used different copper complexes that were coupled to TiO2 nanoparticles. Nanoparticles were prepared with the sol-gel method. The Cu/TiO2 nanoparticles were characterized through ultraviolet-visible and Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, nitrogen physisorption analysis, and scanning electron microscopy. Their biological activity was determined through DNA degradation and their cytotoxic effect on HeLa cells. The Cu/TiO2 nanoparticles presented a pore size between 2 and 6 nm, the size of nanoparticles agglomerates was between 100 and 500 nm. The nanoparticles of Cu/TiO2 degraded DNA starting at 15 min. The half maximal inhibitory concentration in HeLa cells depends on the used cooper complexes, the kinetics of cell death is of first order. Results revealed that these nanoparticles could be applied in uterine-cervical cancer treatment.

Frecuencia y caracterización de Staphylococcus spp. en la mucosa bucal de pacientes diabéticos y no diabéticos / Frequency and characterization of Staphylococcus spp. in the buccal mucosa of diabetic and non-di

Antecedentes: Dentro de la gran diversidad de microorganismos en la microbiota oral, el género Staphylococcus es causante de una gran variedad de infecciones, desde leves hasta diseminadas que pueden causar la muerte. Los portadores de estas bacterias tienen más riesgo de presentar infecciones por estas mismas. Un grupo vulnerable de sufrir infecciones por estos microorganismos son los pacientes diabéticos por sus características sistémicas propias de la enfermedad, deterioro inmunológico y locales bucales, por lo que es importante conocer si son portadoras de este grupo de bacterias. Objetivo: Determinar la frecuencia de colonización por Staphylococcus spp. en aislamientos obtenidos de la mucosa bucal de pacientes diabéticos y sin diabetes. Material y métodos: Se tomó un raspado superficial de la mucosa bucal de personas diabéticas y sin diabetes para cultivo y análisis microbiológico. Se sembró en agar sal manitol y los aislados se identificaron por galerías API Staph. La concentración de glucosa se determinó con equipo Accu-Chek. El análisis fue descriptivo, las diferencias y asociaciones se investigaron con χ2 y T Student. Se consideró estadísticamente significativo cuando el valor de p < 0.05. Resultados: La colonización por Staphylococcus spp. total fue de 73.7%, no hubo diferencia significativa entre diabéticos y no diabéticos (p = 0.946). S. epidermidis se identificó en 69% y S. aureus en 17.6%, sin diferencia entre ambos grupos con p = 0.556 y p = 0.428 respectivamente. Setenta y seis por ciento de los pacientes portadores de prótesis bucales estaban colonizados con Staphylococcus spp. Conclusiones: No se encontró que los pacientes diabéticos tuvieran porcentajes significativamente mayores de colonización por Staphylococcus spp. a pesar de sus condiciones particulares inmunológicas, glucemia anormal y disminución de flujo salival en la cavidad bucal (AU)

Background: Within the great diversity of microorganisms in the buccal microbiota, the genus Staphylococcus is the cause of a great variety of infections ranging from mild to disseminated, which can cause death. The carriers of these bacteria are more at risk of developing infections by themselves. A vulnerable group to suffer infections by these microorganisms are diabetic patients due to their systemic characteristics of the disease, immunological deterioration and local buccal, so it is important to know if they are carriers of this group of bacteria. Objective: The objective was determined the frequency of colonization by Staphylococcus spp. in isolates obtained from the oral mucosa of diabetic and without diabetes patients. Material and methods: A superficial scraping of the buccal mucosa of diabetic and without diabetes people was taken for culture and microbiological analysis. It was seeded in sal manitol agar and the isolates were identified by API Staph galleries. The glucose concentration was determined with Accu-Chek equipment. The analysis was descriptive, differences and associations were investigated with χ2 and Student T. It was considered statistically significant when the value of p < 0.05. Results: Total colonization by Staphylococcus spp. was 73.7%, there was no significant difference between diabetics and nondiabetics (p = 0.946). S. epidermidis was identified in 69% and S. aureus in 17.6%, without difference between both groups with p = 0.556 and p = 0.428 respectively. 76% of patients with oral prostheses were colonized with Staphylococcus spp. Conclusions: Diabetic patients were not found to have significantly higher rates of colonization by Staphylococcus spp. despite their particular immunological conditions, abnormal glycemia and decreased salivary flow in the oral cavity (AU)