Streptococcus pneumoniae and Staphylococcus aureus cause significant morbidity and mortality worldwide. We investigated both the colonization and co-colonization characteristics for these pathogens among 250 healthy children from 2 to 5 years of age in Merida, Venezuela, in 2007. The prevalence of S. pneumoniae colonization, S. aureus colonization, and S. pneumoniae–S. aureus co-colonization was 28%, 56%, and 16%, respectively. Pneumococcal serotypes 6B (14%), 19F (12%), 23F (12%), 15 (9%), 6A (8%), 11 (8%), 23A (6%), and 34 (6%) were the most prevalent. Non-respiratory atopy was a risk factor for S. aureus colonization (p = 0.017). Vaccine serotypes were negatively associated with preceding respiratory infection (p = 0.02) and with S. aureus colonization (p = 0.03). We observed a high prevalence of pneumococcal resistance against trimethoprim–sulfamethoxazole (40%), erythromycin (38%), and penicillin (14%). Semi-quantitative measurement of pneumococcal colonization density showed that children with young siblings and low socioeconomic status were more densely colonized (p = 0.02 and p = 0.02, respectively). In contrast, trimethoprim–sulfamethoxazole- and multidrug-resistant-pneumococci colonized children sparsely (p = 0.03 and p = 0.01, respectively). Our data form an important basis to monitor the future impact of pneumococcal vaccination on bacterial colonization, as well as to recommend a rationalized and restrictive antimicrobial use in our community.

The respiratory tract pathogenStreptococcus pneumoniaeneeds to adapt to the different levels of carbon dioxide (CO₂) it encounters during transmission, colonization, and infection. Since CO₂is important for various cellular processes, factors that allow optimal CO₂sequestering are likely to be important for pneumococcal growth and survival. In this study, we showed that the putative pneumococcal carbonic anhydrase (PCA) is essential forin vitrogrowth ofS. pneumoniaeunder the CO₂-poor conditions found in environmental ambient air. Enzymatic analysis showed that PCA catalyzes the reversible hydration of CO₂to bicarbonate (HCO₃⁻), an essential step to prevent the cellular release of CO₂. The addition of unsaturated fatty acids (UFAs) reversed the CO₂-dependentin vitrogrowth inhibition ofS. pneumoniaestrains lacking thepcagene (Δpca), indicating that PCA-mediated CO₂fixation is at least associated with HCO₃⁻-dependentde novobiosynthesis of UFAs. Besides being necessary for growth in environmental ambient conditions, PCA-mediated CO₂fixation pathways appear to be required for intracellular survival in host cells. This effect was especially pronounced during invasion of human brain microvascular endothelial cells (HBMEC) and uptake by murine J774 macrophage cells but not during interaction ofS. pneumoniaewith Detroit 562 pharyngeal epithelial cells. Finally, the highly conservedpcagene was found to be invariably present in both CO₂-independent and naturally circulating CO₂-dependent strains, suggesting a conserved essential role for PCA and PCA-mediated CO₂fixation pathways for pneumococcal growth and survival.

Obesity is a pathology whose incidence is increasing throughout the world. There are many pathologies associated with obesity. In recent years, the influence of the microbiota on both health and pathological states has been known. There is growing information related to changes in the microbiome and obesity, as well as its associated pathologies. Changes associated with age, exercise, and weight changes have been described. In addition, metabolic changes associated with the microbiota, bariatric surgery, and fecal matter transplantation are described. In this review, we summarize the biology and physiology of microbiota in obese patients, its role in the pathophysiology of several disorders associated, and the emerging therapeutic applications of prebiotics, probiotics, and fecal microbiota transplantation.

Scientific research is a key component of medical education, fostering critical thinking and evidence-based practice. However, international studies have reported wide variability in medical students’ attitudes toward research, shaped by institutional culture, exposure, and curricular design. In parallel, perceived barriers—such as academic overload, lack of mentorship, and insufficient training—are frequently cited as major obstacles that limit student involvement. Understanding students’ predispositions and the barriers they face is essential for developing effective strategies, especially in educational contexts where research participation is limited. This study aimed to evaluate the situation at a private medical school in Ecuador. To evaluate medical students’ attitudes toward and perceptions of barriers to research and to analyze changes in these variables following an educational and motivational intervention. A quasiexperimental study (without a control group) was conducted with 90 undergraduate medical students. The intervention consisted of educational and motivational audiovisual content delivered over one month. A validated questionnaire assessed students’ attitudes and perceived barriers before and after the intervention. Descriptive statistics and a one-sample t-test were used to assess changes. Prior to the intervention, the mean attitude score was 104.72, well above the scale midpoint (78), indicating a generally favorable predisposition. Most students (73.3%) scored above 75% of the maximum possible score in attitudes. For perceived barriers, the initial mean was 109.61, also above the scale midpoint (87), reflecting a high level of perceived obstacles. A total of 96.7% of students scored above 50%, with key concerns related to time constraints, lack of mentorship, and insufficient training in scientific writing and statistics. After the intervention, both the mean attitude score and the mean barrier score remained statistically unchanged. Although the intervention produced a small increase in favorable attitudes, it did not reduce perceived barriers. These findings suggest that short, self-directed strategies are insufficient to address institutional challenges. More effective approaches may require long-term, interactive programs supported by curricular integration, structured mentorship, and institutional investment to foster meaningful research engagement among medical students. Not applicable.

Among a collection of 48 multidrug-resistant pneumococcal strains colonizing healthy children in a small municipality of Mérida, Venezuela, we identified sequence types (STs) related to a variety of internationally spreading drug-resistant clones, as well as ST135, thus far isolated only in Europe. The clones invariably harbored one or more of the Tn 916 -related transposons Tn 3872 , Tn 5253 , Tn 6002 , Tn 2009 , and Tn 2010 . Finally, our data suggest both structural rearrangements in certain transposons and occurrence of novel transposable elements.