Evaluation of chemokines and receptors in gnotobiotic root canal infection by F. nucleatum and E. faecalis

Abstract The present study aims to evaluate the longitudinal effects of induced experimental infections in gnotoxenic animals on the expression of inflammatory chemokines and their receptors in periradicular tissues. The null hypothesis tested was that Enterococcus faecalis and Fusobacterium nucleatum had no effect on CCR5, CCL5, CXCL10, CCL2/MCP-1, CXCR2 and CCR1 expression. Two groups of five animals (n = 5) aged between 8 and 12 weeks were used in this study. The animals were anaesthetized, and coronary access was performed in the first molar on the right and left sides. Microorganisms were inoculated into the left molar, and the right molar was sealed without contamination to function as a control. Animals were sacrificed 7 and 14 days after infection, and periapical tissues were collected. The cytokine mRNA expression levels were assessed using real-time PCR. The chemokine mRNA expression levels demonstrated that the experimental infection was capable of inducing increased chemokine expression on day 7 compared to that on day 14, except for CCR5 and CCL5, which showed no changes. The gnotoxenic animal model proved to be effective and allowed evaluation of the immune response against a known infection. Additionally, this study demonstrates that gene expression of chemokines and their receptors against the experimental infection preferentially prevailed during the initial phase of induction of the periradicular alteration (i.e., on day 7 post-infection).

Risk of vancomycin-resistant enterococci bloodstream infection among patients colonized with vancomycin-resistant enterococci

Background: Vancomycin-resistant enterococci colonization has been reported to increase the risk of developing infections, including bloodstream infections. Aim: In this study, we aimed to share our experience with the vancomycin-resistant enterococci bloodstream infections following gastrointestinal vancomycin-resistant enterococci colonization in pediatric population during a period of 18 months. Method: A retrospective cohort of children admitted to a 400-bed tertiary teaching hospital in Izmir, Turkey whose vancomycin-resistant enterococci colonization was newly detected during routine surveillances for gastrointestinal vancomycin-resistant enterococci colonization during the period of January 2009 and December 2012 were included in this study. All vancomycin-resistant enterococci isolates found within 18 months after initial detection were evaluated for evidence of infection. Findings: Two hundred and sixteen patients with vancomycin-resistant enterococci were included in the study. Vancomycin-resistant enterococci colonization was detected in 136 patients (62.3%) while they were hospitalized at intensive care units; while the remaining majority (33.0%) were hospitalized at hematology-oncology department. Vancomycinresistant enterococci bacteremia was present only in three (1.55%) patients. All these patients were immunosuppressed due to human immunodeficiency virus (one patient) and intensive chemotherapy (two patients). Conclusion: In conclusion, our study found that 1.55% of vancomycin-resistant enterococcicolonized children had developed vancomycin-resistant enterococci bloodstream infection among the pediatric intensive care unit and hematology/oncology patients; according to our findings, we suggest that immunosupression is the key point for developing vancomycinresistant enterococci bloodstream infections. .

Efeitos do aditivo do leite materno com ferro sobre as propriedades bacteriostáticas do leite materno / Effects of human milk fortifier with iron on the bacteriostatic properties of breast milk

OBJETIVO: Comparar o crescimento bacteriano em colostro puro e colostro com aditivo do leite materno contendo ferro. MÉTODOS: Foram comparadas 78 amostras de colostro puro ou colostro com adição de aditivo do leite materno contendo ferro para avaliar o crescimento de Escherichia coli, Staphylococcus aureus e Pseudomonas aeruginosa. Para a análise qualitativa, discos de papel-filtro foram imersos em amostras de cada grupo e incubados por 48 horas com 10¹ Unidades Formadoras de Colônias/mL de cada cepa. Para a avaliação quantitativa, 1 mL de cada cepa contendo 10(7) Unidades Formadoras de Colônias/mL foi homogeneizado com 1 mL, tanto de colostro puro quanto de colostro com aditivo do leite materno, espalhado em placa de Petri e incubado a 37ºC. O número de Unidades Formadoras de Colônias foi contado 24 horas depois. RESULTADOS: A análise qualitativa não mostrou nenhuma diferença no crescimento bacteriano. Na avaliação quantitativa, o crescimento de Escherichia coli (EC) no grupo C foi de 29,4±9,7 x 10(6) CFU/mL, enquanto no grupo FM85 foi de 31,2±10,8 x 10(6) CFU/mL. A diferença entre o crescimento médio foi de 1,9±4,9 x 10(6) CFU/mL (p = 0,001). Não houve diferenças no crescimento de Staphylococcus aureus e Pseudomonas aeruginosa. CONCLUSÃO: A adição de ferro a essa concentração reduz a ação bacteriostática do leite materno contra Escherichia coli.

OBJECTIVE: To compare bacterial growth in pure colostrum versus colostrum with human milk fortifier (HMF) containing iron. METHODS: The growth of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa in 78 samples of pure colostrum or colostrum with added iron-containing HMF was compared. For qualitative analysis, filter paper discs were immersed in samples from each group and incubated for 48 hours with 10¹ colony forming units (CFUs)/mL of each strain. For quantitative assessment, 1 mL of each strain containing 10(7) CFUs/mL was homogenized with 1 mL of either colostrum or colostrum with human milk fortifier, seeded into a Petri dish, and incubated at 37ºC. Twenty-four hours later, the number of CFUs was counted. RESULTS: The qualitative analysis showed no difference in bacterial growth. In the quantitative evaluation, E. coli growth in the control group was 29.4±9.7 x 10(6) CFU/ mL, while in the HMF group it was 31.2±10.8 x 10(6) CFU/mL. The difference between the average growth was 1.9±4.9 x 10(6) CFU/mL (p = 0.001). There were no differences in S. aureus and P. aeruginosa growth. CONCLUSION: Addition of iron at this concentration reduces breast milk bacteriostatic action against E. coli.