Genotipagem de Pseudomonas aeruginosa isoladas de água de hemodiálise.

Abstract

Background: The association between Pseudomonas aeruginosa in dialysis circuits, and infections is evidenced by several studies. Therefore, the use of molecular techniques, such as pulsed-field gel electrophoresis (PFGE), provides important information about genetic diversity, prevalence of clones and tracking sources of infection. Objectives: This study aimed to investigate the potential clonal dissemination of P. aeruginosa in a hemodialysis center in southeastern Brazil, analyzing patient and water samples collected at different distribution points using the PFGE technique. Methods: During the collection period, from 2004 to 2006, 69 strains of Pseudomonas sp. were recovered from a hemodialysis center as well as from patients and stored for future experiments. Eight representative P. aeruginosa isolates were selected for molecular typing by PFGE. Computational analysis was performed with the Gel Analyzer software, and pulsotypes were defined based on similarity of 80% or more in the dendrogram. Results: Of the strains of Pseudomonas sp. isolated, P. aeruginosa represented the majority (55.1%). The microorganisms were widely found in several sources, including dialysis circuit water after reverse osmosis (17.4%), in the waters of rooms A (15.9%), B (18.8%) and C (17.4%), as well as in dialysis machines (27.5%). Two strains were identified in patients, corresponding to 2.9% of the total, one recovered from the catheter tip and the other from a blood sample. The PFGE result revealed the presence of six distinct electrophoretic profiles (A-F), with the existence of a prevalent clone (A) and five different pulsotypes. Pulsotype A was identified both in a clinical sample and in the water from Room A, at different times. Different pulsotypes were identified in post-reverse osmosis water and in dialysis rooms (A1, F, D) during the same period. Conclusions: P. aeruginosa was widely identified in the dialysis circuit and in patient samples at the studied center. PFGE analysis revealed distinct pulsotypes, with clone A being the most prevalent. Clonal spread suggests that several points in the circuit may be sources of pathogen transmission. Strengthening control and surveillance systems, especially regarding water quality, is crucial to enhance patient safety.