Evaluation of the polyphenolic profile of native Ecuadorian stingless bee honeys (Tribe: Meliponini) and their antibiofilm activity on susceptible and multidrug-resistant pathogens: An exploratory analysis.

Biofilms are associated with infections that are resistant to conventional therapies, contributing to the antimicrobial resistance crisis. The need for alternative approaches against biofilms is well-known. Although natural products like stingless bee honeys (tribe: Meliponini) constitute an alternative treatment, much is still unknown. Our main goal was to evaluate the antibiofilm activity of stingless bee honey samples against multidrug-resistant (MDR) pathogens through biomass assays, fluorescence (cell count and viability), and scanning electron (structural composition) microscopy. We analyzed thirty-five honey samples at 15% (v/v) produced by ten different stingless bee species (Cephalotrigona sp., Melipona sp., M. cramptoni, M. fuscopilosa, M. grandis, M. indecisa, M. mimetica, M. nigrifacies, Scaptotrigona problanca, and Tetragonisca angustula) from five provinces of Ecuador (Tungurahua, Pastaza, El Oro, Los Ríos, and Loja) against 24-h biofilms of Staphylococcus aureus, Klebsiella pneumoniae, Candida albicans, and Candida tropicalis. The present honey set belonged to our previous study, where the samples were collected in 2018-2019 and their physicochemical parameters, chemical composition, mineral elements, and minimal inhibitory concentration (MIC) were screened. However, the polyphenolic profile and their antibiofilm activity on susceptible and multidrug-resistant pathogens were still unknown. According to polyphenolic profile of the honey samples, significant differences were observed according to their geographical origin in terms of the qualitative profiles. The five best honey samples (OR24.1, LR34, LO40, LO48, and LO53) belonging to S. problanca, Melipona sp., and M. indecisa were selected for further analysis due to their high biomass reduction values, identification of the stingless bee specimens, and previously reported physicochemical parameters. This subset of honey samples showed a range of 63-80% biofilm inhibition through biomass assays. Fluorescence microscopy (FM) analysis evidenced statistical log reduction in the cell count of honey-treated samples in all pathogens (P <0.05), except for S. aureus ATCC 25923. Concerning cell viability, C. tropicalis, K. pneumoniae ATCC 33495, and K. pneumoniae KPC significantly decreased (P <0.01) by 21.67, 25.69, and 45.62%, respectively. Finally, scanning electron microscopy (SEM) analysis demonstrated structural biofilm disruption through cell morphological parameters (such as area, size, and form). In relation to their polyphenolic profile, medioresinol was only found in the honey of Loja, while scopoletin, kaempferol, and quercetin were only identified in honey of Los Rios, and dihydrocaffeic and dihydroxyphenylacetic acids were only detected in honey of El Oro. All the five honey samples showed dihydrocoumaroylhexose, luteolin, and kaempferol rutinoside. To the authors' best knowledge, this is the first study to analyze stingless bees honey-treated biofilms of susceptible and/or MDR strains of S. aureus, K. pneumoniae, and Candida species.

Evaluation of the biofilm life cycle between Candida albicans and Candida tropicalis.

Candida tropicalis is an emergent pathogen with a high rate of mortality associated with its biofilm formation. Biofilm formation has important repercussions on the public health system. However, little is still known about its biofilm life cycle. The present study analyzed the biofilm life cycle of Candida albicans and C. tropicalis during various timepoints (24, 48, 72, and 96 h) through biomass assays, colony-forming unit (CFU) counting, and epifluorescence and scanning electron microscopies. Our results showed a significant difference between C. albicans and C. tropicalis biofilms in each biomass and viability assay. All-time samples in the biomass and viability assays confirmed statistical differences between the Candida species through pairwise Wilcoxon tests (p < 0.05). C. albicans demonstrated a lower biomass growth but reached nearly the same level of C. tropicalis biomass at 96 h, while the CFU counting assays exhibited a superior number of viable cells within the C. tropicalis biofilm. Statistical differences were also found between C. albicans and C. tropicalis biofilms from 48- and 72-h microscopies, demonstrating C. tropicalis with a higher number of total cells within biofilms and C. albicans cells with a superior cell area and higher matrix production. Therefore, the present study proved the higher biofilm production of C. tropicalis.

Prevalence of biofilms in Candida spp. bloodstream infections: A meta-analysis.

CONTEXT: Candida-related infections are nowadays a serious Public Health Problem emerging multidrug-resistant strains. Candida biofilm also leads bloodstream infections to invasive systemic infections. OBJECTIVE: The present meta-analysis aimed to analyze Candida biofilm rate, type, and antifungal resistance among hospitalized patients between 1995 and 2020. DATA SOURCES: Web of Science, Scopus, PubMed, and Google Scholar databases were searched for English papers using the following medical subject heading terms (MESH): "invasive candidiasis"; "bloodstream infections"; "biofilm formation"; "biofilm-related infections"; "mortality"; and "prevalence". STUDY SELECTION: The major inclusion criteria included reporting the rate of biofilm formation and the prevalence of biofilm-related to Candida species, including observational studies (more exactly, cohort, retrospective, and case-control studies). Furthermore, data regarding the mortality rate, the geographical location of the study set, and the use of anti-fungal agents in clinical isolates were also extracted from the studies. DATA EXTRACTION: Independent extraction of articles by 2 authors using predefined data fields, including study quality indicators. DATA SYNTHESIS: A total of 31 studies from publicly available databases met our inclusion criteria. The biofilm formation in the data set varied greatly from 16 to 100% in blood samples. Most of the studies belonged to Europe (17/31) and Asia (9/31). Forest plot showed a pooled rate of biofilm formation of 80.0% (CI: 67-90), with high heterogeneity (Q = 2567.45, I2 = 98.83, τ2 = 0.150) in random effects model (p < 0.001). The funnel plot and Egger's linear regression test failed to find publication bias (p = 0.896). The mortality rate in Candida-related bloodstream infections was 37.9% of which 70.0% were from biofilm-associated infections. Furthermore, Candida isolates were also characterized in low, intermediate, or high biofilm formers through their level of biofilm mass (crystal violet staining or XTT assays) after a 24h growth. When comparing between countries, statistical differences were obtained (p = 0.0074), showing the lower and higher biofilm prevalence values in Italy and Spain, respectively. The prevalence of low, intermediate, and high biofilms were 36.2, 18.9, and 35.0% (p < 0.0001), respectively. C. tropicalis was the prevalent species in high biofilm formation (67.5%) showing statistically significant differences when compared to other Candida species, except for C. krusei and C. glabrata. Finally, the rates of antifungal resistance to fluconazole, voriconazole, and caspofungin related to biofilm were 70.5, 67.9 and 72.8% (p < 0.001), respectively. CONCLUSIONS: Early detection of biofilms and a better characterization of Candida spp. bloodstream infections should be considered, which eventually will help preserve public health resources and ultimately diminish mortality among patients.

Marcadores hematológicos y bioquímicos para el diagnóstico precoz de bacteriemiascausadas por Enterobacteriaceae resistentes a los carbapenémicos / Haematological and biochemical markers for the early diagnosis of bacteremias caused bycarbapenem-resistant Enterobacteriaceae

INTRODUCCIÓN. Las bacteriemias causadas por Enterobacteriaceae resistentes a carbapenémicos se asocian con altas tasas de mortalidad a diferencia de las bacteriemias causadas por Enterobacteriaceae sensibles a carbapenémicos. Los hallazgos clínicos y de laboratorio son importantes para determinar los esquemas terapéuticos y su pronóstico; su diagnóstico precoz resulta esencial para un manejo adecuado. OBJETIVO. Relacionar valores de marcadores sanguíneos y bioquímicos en bacteriemias causadas por Enterobacteriaceae resistentes a carbapenémicos. MATERIALES Y MÉTODOS. Estudio analítico transversal. Población de 427 y muestra de 224 datos de hemocultivos positivos para Enterobacteriaceae de pacientes atendidos en el Hospital de Especialidades Carlos Andrade Marín en el periodo mayo 2016 a julio 2018. Criterios de inclusión: i) al menos un hemocultivo positivo; ii) recuperación del aislado de CRE o CSE y iii) recolección simultanea de muestras de sangre y pruebas de laboratorio. Criterios de exclusión: i) bacteriemias polimicrobianas; ii) valores fuera de rango y iii) reportes sin valores numéricos. El análisis de datos se realizó mediante el programa estadístico International Business Machines Statistical Package for the Social Sciences versión 24.0. RESULTADOS. Se demostró que el recuento de leucocitos [OR 1,21 (95% IC: 1,03-1,43)], el recuento de plaquetas [OR 1,65 (95% IC: 1,37-1,98)] y el tiempo parcial de tromboplastina [OR 1,29 (95% IC: 1,04-1,60)] fueron buenas variables predictoras independientes, mediante análisis de regresión logística multivariante. CONCLUSIÓN. La trombocitopenia y el tiempo parcial de tromboplastina prolongado se asociaron con bacteremia causada por Enterobacteriaceae resistentes a carbapenémicos.

INTRODUCTION. Bacteremias caused by carbapenem-resistant Enterobacteriaceae are associated with high mortality rates in contrast to bacteremias caused by carbapenem-sensitive Enterobacteriaceae. Clinical and laboratory findings are important in determining therapeutic regimens and prognosis; early diagnosis is essential for appropriate management. OBJECTIVE. To relate blood and biochemical marker values in bacteremia caused by carbapenem-resistant Enterobacteriaceae. MATERIALS AND METHODS. Cross-sectional analytical study. Population of 427 and sample of 224 blood culture data positive for Enterobacteriaceae from patients attended at the Carlos Andrade Marín Specialties Hospital in the period May 2016 to July 2018. Inclusion criteria: i) at least one positive blood culture; ii) recovery of CRE or CSE isolate and iii) simultaneous collection of blood samples and laboratory tests. Exclusion criteria: i) polymicrobial bacteremia; ii) out-of-range values and iii) reports without numerical values. Data analysis was performed using the statistical program International Business Machines Statistical Package for the Social Sciences version 24.0. RESULTS. Leukocyte count [OR 1.21 (95% CI: 1.03-1.43)], platelet count [OR 1.65 (95% CI: 1.37- 1.98)] and partial thromboplastin time [OR 1.29 (95% CI: 1.04-1.60)] were shown to be good independent predictor variables, by multivariate logistic regression analysis. CONCLUSION. Thrombocytopenia and prolonged partial thromboplastin time were associated with bacteremia caused by carbapenem-resistant Enterobacteriaceae.