Staphylococcus aureus colonization increases the risk of invasive infections in different groups of patients. We analyzed the dynamics and factors associated with S. aureus colonization in hemodialysis patients. A longitudinal study was conducted at a dialysis center associated with a tertiary health care institution. S. aureus colonization was assessed three times in nostrils and on the skin and was classified as absent, intermittent or persistent. The molecular analysis included pulsed-field gel electrophoresis (PFGE) and spa-typing. Clonal complex was inferred from spa-typing. A model of generalized estimating equations was performed to determine the factors associated with colonization. A total of 210 patients were included. Colonization by methicillin-susceptible (MSSA) and methicillin-resistant (MRSA) isolates was 29.1 % vs. 4.8 %, 29.2 % vs. 6.7 % and 24.1 % vs. 7.1 % in the first, second and third screenings respectively. Most of the colonized patients were intermittent carriers (77.8 %, n = 63). PFGE and spa-typing revealed a high genetic diversity. One third (33.3 %) of the carriers classified as persistent had different clones during follow-up. Clonal complex 8 was frequent among MSSA (28 %) and MRSA (59 %) isolates. Current smoking (OR:7.22, 95 %CI 2.24-23.27), Charlson index (OR:1.22, 95 %CI 1.03-1.43) and previous infection by S. aureus (OR:2.41; 95 %CI:1.09-5.30) were associated with colonization by this microorganism. Colonization increased the risk of bacteremia (HR = 4.9; 95 % CI: 1.9-12.9). In conclusion, the colonization by S. aureus in hemodialysis patients changes over time and acquisition of new clones is a frequent event. These results evidence that patients are repeatedly recolonizing from hospitals, dialysis units and their homes. On the other hand, factors not associated with healthcare, as smoking, can increase the risk of colonization.

Objective: Staphylococcus aureus is responsible for a large number of infections in pediatric population; however, information about the behavior of such infections in this population is limited. The aim of the study was to describe the clinical, epidemiological, and molecular characteristics of infections caused by methicillin-susceptible and resistant S. aureus (MSSA-MRSA) in a pediatric population. Method: A cross-sectional descriptive study in patients from birth to 14 years of age from three high-complexity institutions was conducted (2008-2010). All patients infected with methicillin-resistant S. aureus and a representative sample of patients infected with methicillin-susceptible S. aureus were included. Clinical and epidemiological information was obtained from medical records and molecular characterization included spa typing, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST). In addition, staphylococcal cassette chromosome mec (SCCmec) and virulence factor genes were detected. Results: A total of 182 patients, 65 with methicillin-susceptible S. aureus infections and 117 with methicillin-resistant S. aureus infections, were included in the study; 41.4% of the patients being under 1 year. The most frequent infections were of the skin and soft tissues. Backgrounds such as having stayed in day care centers and previous use of antibiotics were more common in patients with methicillin-resistant S. aureus infections (p <= 0.05). Sixteen clonal complexes were identified and methicillin-susceptible S. aureus strains were more diverse. The most common cassette was staphylococcal cassette chromosomemec IVc (70.8%), which was linked to Panton-Valentine leukocidin (pvl). Conclusions: In contrast with other locations, a prevalence of infections in children under 1 year of age in the city could be observed; this emphasizes the importance of epidemiological knowledge at the local level. (C) 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda.

Wastewater is a hotspot for the spread of antimicrobial resistance (AR); therefore, bacteriophages offer a promising biocontrol alternative to overcome the limitations of conventional disinfection. This study evaluated the efficacy of bacteriophages and cocktails for the biocontrol of carbapenem-resistant Klebsiella pneumoniae (CR-Kp) (CG258 and ST307) and Escherichia coli producers of extended-spectrum β-lactamases (ESBL-Ec) (ST131) in simulated wastewater. A synthetic wastewater matrix was prepared in which bacterial viability and bacteriophage stability were assessed for 72 h. CR-Kp or ESBL-Ec strain were treated with individual bacteriophages or phage-cocktails (dosed in different ways) and bacterial loads were monitored for 54 h. The Klebsiella phages FKP3 and FKP14 eliminated 99% (−2.9 Log) of CR-Kp-CG258 at 54 h, and FKP10 reduced 99% (−2.15 Log) of the CR-Kp-ST307 strains. The Klebsiella phage-cocktail in a single dose reduced to 99.99% (−4.12 Log) of the CR-Kp-CG258 at 36 h. Coliphage FEC1 reduced to 2.12 Log (99%) of ESBL-Ec-bla_CTX-M-G9, and FEC2 and FEC4 reduced approximately 1 Log (90%) of ESBL-Ec-bla_CTX-M-G9 and bla_CTX-M-G1. The coliphage cocktail increased the reduction up to 2.2 Logarithms. This study provides evidence supporting the use of bacteriophage cocktails for the control of resistant bacteria in wastewater, a sustainable intervention to mitigate the spread of AR and support water reuse safety.