During the past decade, studies on the composition of human microbiota and its relation to the host became one of the most explored subjects of the medical literature. The development of high-throughput molecular technologies allowed a deeper characterization of human microbiota and a better understanding of its relationship with health and disease. Changes in human habits including wide use of antimicrobials can result in dysregulation of host–microbiome homeostasis, with multiple consequences. The purpose of this review is to highlight the most important evidence in the literature of host–microbiome interactions and illustrate how these intriguing relations may lead to new treatment and prevention strategies.

Objectives: To determine the impact of an educational program on the prevention of central venous catheter-related infections in a Brazilian Pediatric Intensive Care Unit. Patients and Methods: All patients admitted to the unit between February 2004 and May 2005 were included in the cohort study in a longitudinal assessment. An educational program was developed based on the Centers for Disease Control and Prevention recommendations for prevention of catheter-associated infections and was adapted to local conditions and resources after an initial observational phase. Incidence of catheter-associated infections was measured by means of on-site surveillance. Results: One hundred eighteen nosocomial infections occurred in 253 patients (46.6 infections per 100 admissions) and in 2,954 patient-days (39.9 infections per 1,000 patient-days). The incidence-density of catheter infections was 31.1 episodes per 1.000 venous central catheter-days before interventions, and 16.5 episodes per 1,000 venous central catheter-days afterwards (relative risk 0.53 [95% CI 0.28-1.01]). Corresponding rates for exit-site catheter infections were 8.0 and 2.5 episodes per 1,000 venous central catheter-days [0.32 (0.07-1.49)], and the rates for bloodstream infections were 23.1 and 13.9 episodes per 1,000 venous central catheter-days, before and after interventions [0.61 (0.32-1.14)]. Conclusion: A prevention strategy targeted at the insertion and maintenance of vascular access can decrease rates of vascular-access infections in pediatric intensive care unit.

E. faecium contendo o gene vanA foi a primeira espécie de VRE descrita, no Brasil. Apesar disto, E. faecalis resistente a vancomicina tem se tornado a espécie predominante nos hospitais brasileiros.O objetivo desse estudo foi avaliar a relação genética de VREs isolados em um hospital de ensino brasileiro após oito anos de seu primeiro isolamento. Analisamos 37 isolados de VRE obtidos de 81 culturas de vigilância de pacientes admitidos nas quatro maiores Unidades de Tratamento Intensivo em Fevereiro de 2006. A presença do gene vanA foi analisada por PCR e a caracterização molecular por PFGE. Todas as amostras VRE carreavam o gene vanA. Entre os E. faecalis vancomicina-resistentes, dois distintos grupos clonais foram observados. E. faecium resistente a vancomicina pertencentes a cinco clones distintos foram demonstrados por tipagem molecular. Todos esses clones foram diferentes do primeiro clone de enterococo resistente a vancomicina isolado oito anos atrás em nosso hospital.

E. faecium was the first reported VRE species, carrying the vanA gene in Brazil. In spite of this, vancomycin-resistant E. faecalis has become the predominant species in Brazilian hospitals. The aim of this study was to evaluate the genetic relatedness of VREs isolated in a Brazilian teaching hospital eight years apart from its first isolation. We analyzed 38 VRE strains obtained from 81 surveillance cultures of patients admitted to the four largest intensive care units in Hospital São Paulo in February, 2006. Presence of the vanA gene was assayed by PCR and PFGE analysis was used for molecular characterization. All VRE strains carried the vanA gene. Two distinct clonal groups were observed among vancomycin-resistant E. faecalis. Vancomycin-resistant E. faecium belonged to five distinct clones were demonstrated by molecular typing. All of these clones were different from the first vancomycin-resistant enterococci clone isolated eight years ago in our hospital.

Potent antimicrobial agents have been developed as a response to the development of antibiotic-resistant bacteria, which especially affect patients with prolonged hospitalization in Intensive Care Units (ICU) and who had been previously treated with antimicrobials, especially third-generation cephalosporins.This study was to determine how changes in the empirical treatment of infections in ICU patients affect the incidence of Gram-negative bacteria species and their susceptibility to antimicrobials, and examine the impact of these changes on nosocomial infections. A prospective interventional study was performed in a university hospital during two periods: 1) First period (September 1999 to February 2000); and 2) Second period (August 2000 to December 2000); empirical treatment was changed from ceftriaxone and/or ceftazidime in the first period to piperacillin/tazobactam in the second. ICU epidemiological and infection control rates, as well as bacterial isolates from upper airways were analyzed. Ceftazidime consumption dropped from 34.83 to 0.85 DDD/1000 patients per day (p=0.004). Piperacillin/tazobactam was originally not available; its consumption reached 157.07 DDD/1000 patients per day in the second period (p=0.0002). Eighty-seven patients and 66 patients were evaluated for upper airway colonization in the first and second periods, respectively. There was a significant decrease in the incidence of K. pneumoniae (p=0.004) and P. mirabilis (p=0.036), restoration of K. pneumoniae susceptibility to cephalosporins (p<0.0001) and reduction of ventilator-associated pneumonia rates (p<0.0001). However, there was an increase in P. aeruginosa incidence (p=0.005) and increases in ceftazidime (p=0.003) and meropenem (p<0.0001) susceptibilities. Changing antimicrobial selective pressure on multi-resistant Gram-negative bacteria helps control ventilator-associated pneumonia and decreases antimicrobial resistance.

Handwashing compliance was compared at two medical- surgical intensive care units (ICUs) of a teaching and a non-teaching hospital. The mean compliance was 22.2% and 42.6%, respectively. Respiratory therapists at the non-teaching hospital had the best handwashing compliance (52.6%). Nursing assistants at the teaching hospital had the worst compliance (11.5%). Nursing assistant was the only health-care worker category with a significant difference between the two ICUs (odds ratio = 6.0; 95% confidence interval = 3.83-9.43; p< 0.001).