Between 30 and 50% of the world population is permanently colonized in some anatomical site by Staphylococcus aureus, although the vast majority are asymptomatic carriers. The nose is its main niche and currently the colonization of S. aureus in the pharynx has become relevant due to the variety of reported carrier rates and the epidemiological importance of the dissemination of Methicillin-resistant S. aureus strains (MRSA) by pharyngeal carriers. For this bacterium to colonize a tissue successfully, it is necessary to establish many interactions with bacterial and host cell components such as bacterial wall teichoic acids (WTA) with the Scavenger SREC-1 host receptor and at the same time evade the defense mechanisms. On the other hand, there are host factors that will facilitate or complicate the colonization or persistence of S. aureus at these sites, such as physiological, genetic, immunological and microbiological factors.

The widespread use of mobile phones (MP) among healthcare personnel might be considered as an important source of contamination. One of the most pathogenic bacteria to humans is Staphylococcus aureus, which can be transmitted through the constant use of MP. Nevertheless, which specific type of strains are transmitted and which are their sources have not been sufficiently studied. The aim of this study is to determine the source of contamination of MP and characterize the corresponding genotypic and phenotypic properties of the strains found. Nose, pharynx, and MP samples were taken from a group of health science students. We were able to determinate the clonality of the isolated strains by pulsed-field gel electrophoresis (PFGE) and spa gene typing (spa-type). Adhesin and toxin genes were detected, and the capacity of biofilm formation was determined. Several of the MP exhibited strains of S. aureus present in the nose and/or pharynx of their owners. methicillin-susceptible Staphylococcus aureus (MSSA), hospital-acquired methicillin-resistant S. aureus (HA-MRSA), and community-acquired methicillin-resistant S. aureus (CA-MRSA) strains were found, which indicated a variety of genotypes. This study concludes that MP can be contaminated with the strains of S. aureus present in the nose and/or pharynx of the owners; these strains can be of different types and there is no dominant genotype.

Staphylococcus aureus is a microorganism that can colonize the nose, pharynx, and other regions of the body. It has also been observed that it can cause persistence. Successful colonization of S. aureus depends in the factors that favor the interaction of the bacteria with host cells. The bacterial determinants of S. aureus that have the capacity to adhere to human tissues involve adhesion factors such as teichoic acids and cell-wall-anchored proteins (CWA) such as ClfA, IcaA, SdrC, FnBPA, among others. The colonization and persistence process first involve adhesion to the tissue, followed by its reproduction and the possible formation of a biofilm. This review will describe the main virulence factors that allow bacterial adhesion and biofilm formation, including the accessory gene regulator genes (agr), related to colonization and persistence of S. aureus.

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.

Introduction. Staphylococcus aureus is a bacterium that colonizes various human sites. The pharynx has been considered as a site of little clinical relevance and little studied. Recently, it has been reported that S. aureus can colonize more the pharynx than the nose. In addition, S. aureus can persist in these sites for prolonged periods of time. Hypothesis. The composition of the pharyngeal and nasal microbiome will differ between persistent, intermittent carriers and non-carriers of S. aureus. Aim. Determine whether the pharyngeal and nasal microbiome is different between carriers and non-carriers of S. aureus. Methodology. S. aureus carriers were monitored by means of pharyngeal and nasal exudates of apparently healthy adult university students for 3 months. Samples from individuals of the same carrier type were pooled, and DNA was extracted and the 16S rRNA was sequenced. The sequences were analysed in MOTHUR v.1.48.0 software, by analysing the percentages of relative abundance in the STAMP 2.1.3 program, in addition to the predictive analysis of metabolic pathways in PICRUSt2. Results. A greater colonization of S. aureus was found in the pharynx than in the nose. The microbiomes of S. aureus carriers and non-carriers do not show significant differences. The main microbiome difference found was between pharyngeal and nasal microbiomes. No significant differences were found in the abundance of the genus Staphylococcus in pharyngeal and nasal S. aureus carriers and non-carriers. The nasal microbiome was found to have more variation compared to the pharyngeal microbiome, which appears to be more stable between individuals and pools. Predictive analysis of metabolic pathways showed a greater presence of Staphylococcus-associated pathways in the nose than in the pharynx. Conclusion. S. aureus can colonize and persist in the pharynx in equal or greater proportion than in the nose. No statistically significant differences were found in the microbiome of the pharyngeal and nasal carriers and non-carriers of S. aureus, but the pharyngeal and nasal microbiomes are different independent of the type of S. aureus carrier or non-carrier. Therefore, the microbiome apparently does not influence the persistence of S. aureus.