Staphylococcus aureus (SA) remains a major cause of nosocomial and community-acquired infections worldwide. Nasal carriage of this bacterium among hospital personnel constitutes an important source for nosocomial infections. A cross-sectional study enrolling the whole medical student population (n=387) of the School of Medicine at the Universidad de Cartagena, Colombia, was conducted to evaluate the carriage rates of both methicillin sensitive- and methicillin resistant-SA, the frequency of Panton-Valentine leukocidin genes in the isolates, and risk factors associated with carriage in this selected population. After signing an informed consent, participants completed a survey related to possible risk factors for colonization, and nasal swabs were collected from anterior nares. Staphylococcus aureus strains isolated from carriers were subjected to DNA extraction and PCR assays to determine the presence of MecA and Panton-Valentine leukocidin genes. Typing of the staphylococcal chromosomal cassette was performed for methicillin resistant strains. Molecular analysis was performed for only one strain per carrier. Prevalence of carriage for methicillin sensitive- and methicillin resistant-SA was 25% and 1.6% respectively. Most of the methicillin resistant isolates carried the staphylococcal chromosomal cassette type IV and the genes for Panton-Valentine leukocidin. To determine carrier types among medical students, each participant was subjected to four additional swabs, each taken two weeks apart. 9.8% persistent carriers, 53.1% intermittent carriers, and 37.1% non-carriers of SA were found. There was no association between risk factors analyzed and carriage of the bacterium. The study was conducted from April to September 2009 and found a persistent carriage of methicillin resistant-SA strains bearing the genes for Panton-Valentine leukocidin among medical students, evidencing the potential contribution of this portion of healthcare personnel either to the spread or introduction of these strains into the healthcare environment.
A number of gene transcripts were differentially expressed by the cell lines assayed. Among them, FMOD was further evaluated in clinical samples and was found to be differentially expressed between benign and prostate cancer tissue. Further validation of FMOD transcript in a larger population is required to ascertain its usefulness as biomarker for prostate cancer.
The expression of fibromodulin was higher in prostatic cancer cells (cell-lines and human tissue) than in normal/benign prostatic cells. Additional studies are required to determine the biological and clinical significance and whether this proteoglycan has a role in carcinogenesis of the prostate or in prostate cancer related inflammatory processes.
Background: The hallmark of tuberculosis is the granuloma, an organized cellular accumulation playing a key role in host defense against Mycobacterium tuberculosis. These structures sequester and contain mycobacterial cells preventing active disease, while long term maintenance of granulomas leads to latent disease. Clear understanding on mechanisms involved in granuloma formation and maintenance is lacking.Objective: To monitor granuloma formation and to determine gene expression profiles induced during the granulomatous response to M. tuberculosis (H37Ra).
Methods:We used a previously characterized in vitro human model. Cellular aggregation was followed daily with microscopy and Wright staining for 5 days. Granulomas were collected at 24h, RNA extracted and hybridized to Affymetrix human microarrays. Resultados: Se observó la formación gradual de granulomas en respuesta a la infección. Los granulomas persistieron por 96 h, y luego se desvanecieron.Conclusiones: Se identificaron genes de la respuesta inmune innata y vías de presentación antigénica activadas durante la respuesta granulomatosa in vitro a células micobacteriales vivas, lo cual reveló alteraciones tempranas de la expresión génica en el inicio de la respuesta granulomatosa humana.
Original Article
Microarray analysis of the in vitro granulomatous response to Mycobacterium tuberculosis H37RaAnálisis con Micromatrices de la respuesta granulomatosa in vitro a Mycobacterium tuberculosis H37Ra
Staphylococcus aureus nasal carriage found in this study was lower than that reported from other similar studies in other countries, taking into account that this is a population at risk for colonisation by this pathogen.
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