Efeito da terapia fotodinâmica antimicrobiana (aPDT) na descolonização nasal de pacientes renais crônicos dialíticos portadores de Staphylococcus aureus: estudo clínico randomizado controlado e cego

Abstract

Infections are an important cause of mortality among patients with chronic kidney disease (CKD) undergoing hemodialysis treatment. Staphylococcus aureus (S. aureus) is a frequent agent and previous nasal colonization is a risk factor for infection. Nasal decolonization by S. aureus reduces infection rates. Conventional treatment is performed with topical mupirocin, but repeated and prolonged use can induce bacterial resistance. Antimicrobial photodynamic therapy (aPDT) is a promising approach due to its bactericidal effect and low tendency to induce drug resistance. Therefore, the aim of this study was to compare the use of aPDT to antimicrobial therapy with mupirocin in the nasal decolonization of patients with CKD with S. aureus on hemodialysis, through qualitative microbiological evaluation and recolonization time. This randomized, controlled, single-blind clinical trial with a 6-month follow-up has 2 groups formed randomly: G1(n=17) - decolonization with aPDT (λ= 660nm, 400mW/cm2, continuous mode, methylene blue 0 .01%, single application) and G2 (n=17) – treatment with mupirocin. Swabs from anterior nasal cavities were collected - at T0 (before intervention - carrier state), T1 (after completion of decolonization - efficacy of decolonization), T2 and T3 (at 1 and 3 months - recolonization). Samples were seeded in aerobic culture medium and bacterial colonies were identified by mass spectrometry - MALDI-TOF and tested for antimicrobial sensitivity profile for S.aureus (Vitek 2). Assessments were carried out regarding adherence and safety of treatments. Guiding questions were applied to assess possible risk factors related to nasal colonization by S. aureus in this population. The efficacy of nasal decolonization was evaluated as an infection prevention strategy, analyzing the incidence of S. aureus infection during the historical comparison period (06 months before randomization) with the same period after treatments. Treatment costs were assessed. The rate of nasal carriers of S. aureus in patients with CKD was 35%, of these, 8.8% were colonized by MRSA (Meticillin-resistant Staphylococcus aureus). Two risk factors were statistically significant for colonization, age and use of corticosteroids/immunosuppressants. There was no difference between treatments (aPDT vs mupirocin) regarding efficacy in decolonization. There were no reports of adverse events with aPDT. Among the 60% of patients with CKD who recolonized (n=15), more than half (66.6%) occurred within 30 days after the treatments. There was no association between nasal decolonization by S. aureus and a decrease in the risk of infection by this agent. Costs per section of treatments (aPDT vs mupirocin) were similar. Therefore, it is concluded that due to the bactericidal effect similar to conventional antimicrobial treatment (mupirocin) with only one application (better adherence) and the absence of induction of bacterial resistance, aPDT reveals itself as a promising therapy in the nasal decolonization of patients with CKD, due to the possibility of being used repeated, promoting a sustained decolonization and thus enabling the reduction of infection by this agent in this population.