ABSTRACT
OBJECTIVES: Candida tropicalis is one of the three most frequent species causing candidaemia in Latin America. Despite the high prevalence of C. tropicalis in candidaemia cases in Brazil, little is known about the trends in fluconazole susceptibility over time. The objective of this study was to evaluate temporal trends in azole resistance rates among C. tropicalis bloodstream isolates from patients treated in six Brazilian medical centres over a 12-year period. METHODS: We selected 200 C. tropicalis bloodstream isolates from six medical centres in Brazil collected between 2007 and 2018. Species identification was confirmed by MALDI-TOF/MS. Antifungal susceptibility testing for four antifungal agents was performed by the Clinical and Laboratory Standards Institute (CLSI) microbroth method. RESULTS: Overall, rates of non-susceptibility were 4% and 3.5% to fluconazole and voriconazole, respectively. All isolates were susceptible to amphotericin B and only one isolate was resistant to echinocandins. CONCLUSION: Although we failed to demonstrate statistical differences in the rates of azole resistance documented during the period of analysis, trends towards lower susceptibility to fluconazole and voriconazole were shown.
Subject(s)
Azoles , Candida tropicalis , Antifungal Agents/pharmacology , Antifungal Agents/therapeutic use , Azoles/pharmacology , Brazil , Candida , Drug Resistance, Fungal , Humans , Microbial Sensitivity TestsSubject(s)
Clostridium Infections/epidemiology , Diarrhea/epidemiology , Diarrhea/microbiology , Adult , Aged , Aged, 80 and over , Brazil/epidemiology , Clostridioides difficile , Female , Humans , Male , Middle Aged , Prevalence , Risk Factors , Young AdultABSTRACT
BACKGROUND: Galactomannan (GM) detection in serum samples has been used to diagnose invasive aspergillosis (IA). Limited sensitivity has been observed in lung transplant recipients, for whom bronchoalveolar lavage (BAL) testing has been advocated. Because airway colonization with Aspergillus species occurs frequently in these patients, false-positive GM results have been reported if the cutoff validated for sera is used (i.e., 0.5). METHODS: Herein, we prospectively studied BAL fluid samples from 60 lung transplant patients to determine the optimal cutoff for BAL GM testing. Only one sample per patient was studied. BAL samples were vortexed and processed according to the manufacturer's instructions for serum samples. Sensitivity, specificity, and likelihood ratios were calculated in reference to proven or probable IA cases using receiver operating characteristic analysis. RESULTS: Eight patients had IA during the study (incidence 13.3%), including four patients with proven IA. Aspergillosis increased 5-fold the risk of death in lung transplant recipients. The positive predictive value of a positive BAL GM test at the 0.5 cutoff was low (24.2%). Raising the cutoff improved test specificity without compromising sensitivity. The best cutoff was defined at 1.5 (sensitivity 100% and specificity 90.4%). CONCLUSIONS: This study reinforces the importance of BAL GM testing in lung transplant recipients, particularly to exclude the diagnosis of IA. To minimize the frequency of false-positive results, a higher test cutoff should be applied to BAL samples, in comparison with serum samples.
