Antibiotics (Basel)
February 2024
spp. are environmental bacteria able to infect animals and humans. Here, we aim to evaluate the role of biofilms in persistence in freshwater.
View Article and Find Full Text PDFThis work presents a comparative analysis of two clinical isolates of , isolated from haemoculture (HC) and central venous catheter (CVC). Both strains harboured Y132F and R398I mutations in the gene associated with resistance to fluconazole (FLC). Differences between the HC and CVC isolates were addressed in terms of virulence, resistance to FLC, and lipid distribution.
View Article and Find Full Text PDFAntibiotics (Basel)
February 2023
The natural bioactive molecule farnesol (FAR) is widely studied mainly for its antibiofilm and antimicrobial properties. In addition, it increases the effectiveness of some antimicrobial substances, which makes it interesting for the development of combined therapy. In the present work, the effect of FAR either alone or in combination with oxacillin (OXA) on mixed biofilms formed by clinically relevant pathogens, and , was studied.
View Article and Find Full Text PDFBiofilm-associated infections are a public health concern especially in the context of healthcare-associated infections such as catheter-related bloodstream infections (CRBSIs). We evaluated the biofilm formation and antimicrobials resistance (AMR) of complex and co-isolated from a CRBSI patient. Antimicrobial susceptibility of central venous catheters (CVCs) and hemoculture (HC) isolates was evaluated, including whole genome sequencing (WGS) resistome analysis and evaluation of gene expression to obtain insight into their AMR determinants.
View Article and Find Full Text PDFThe increase in bacterial resistance to antibiotics has led researchers to find new compounds or find combinations between different compounds with potential antibacterial action and with the ability to prevent the development of antibiotic resistance. Polyoxotungstates (POTs) are inorganic clusters that may fulfill that need, either individually or in combination with antibiotics. Herein, we report the ability of the polyoxotungstates (POTs) with Wells-Dawson P2W18, P2W17, P2W15, and Preyssler P5W30 type structures to differently affect Gram-negative and Gram-positive microorganisms, either susceptible or resistant to antibiotics.
View Article and Find Full Text PDFFreshwater pollution is a huge concern. A study aiming to evaluate physico-chemical characteristics, microbiota, occurrence of two groups of persistent environmental pollutants with similar chemical properties (polycyclic aromatic hydrocarbons- PAHs and microplastics - MPs) in Alqueva's surface water was performed during 2021. Water samples were collected at three spots related to touristic activities (two beaches and one marina) during the Winter, Spring, Summer and Autumn seasons.
View Article and Find Full Text PDFSolvent-free microwave extraction (SFME) is a combination of microwave heating and dry distillation performed at atmospheric pressure without the addition of water or organic solvents that has been proposed as a green method for the extraction of essential oils from aromatic and medicinal herbs. In this work, SFME and the conventional techniques of steam distillation (SD) and hydrodistillation (HD) were compared with respect to the extraction and antioxidant and antimicrobial activities of essential oil. The main constituent of essential oils obtained using different methods was 1,8-cineole (eucalyptol).
View Article and Find Full Text PDFAntibiotics (Basel)
November 2020
Nontuberculous mycobacteria (NTM) and many fungal species (spp.) are commonly associated with opportunistic infections (OPIs) in immunocompromised individuals. Moreover, occurrence of concomitant infection by NTM (mainly spp.
View Article and Find Full Text PDFBacterial biofilms are an important virulence factor with a vital role in evasion from the host immune system, colonization and infection. The aim of the present study was to evaluate in vitro the effects of three environmental factors (H, glucose and human plasma) in biofilm formation, by carrier and invasive Streptococcus agalactiae strains of ST17 and ST19 sequence types, including DNase producers and non-producers. Bacteria ability to assemble biofilms was classified based on crystal violet assay.
View Article and Find Full Text PDFAs part of the Biology and Mars Experiment (BIOMEX; ILSRA 2009-0834), samples of the lichen were placed on the exposure platform EXPOSE-R2, on the International Space Station (ISS) and exposed to space and to a Mars-simulated environment for 18 months (2014-2016) to study: (1) resistance to space and Mars-like conditions and (2) biomarkers for use in future space missions (Exo-Mars). When the experiment returned (June 2016), initial analysis showed rapid recovery of photosystem II activity in the samples exposed exclusively to space vacuum and a Mars-like atmosphere. Significantly reduced recovery levels were observed in Sun-exposed samples, and electron and fluorescence microscopy (transmission electron microscope and field emission scanning electron microscope) data indicated that this was attributable to the combined effects of space radiation and space vacuum, as unirradiated samples exhibited less marked morphological changes compared with Sun-exposed samples.
View Article and Find Full Text PDFAlthough infectious disease risk from recreational exposure to waterborne pathogens has been an active area of research for decades, beach sand is a relatively unexplored habitat for the persistence of pathogens and fecal indicator bacteria (FIB). Beach sand, biofilms, and water all present unique advantages and challenges to pathogen introduction, growth, and persistence. These dynamics are further complicated by continuous exchange between sand and water habitats.
View Article and Find Full Text PDFNontuberculous Mycobacteria (NTM) respiratory infections have been gradually increasing. Here, THP-1 cells were used as a model to evaluate intracellular persistence of three NTM species (reference and clinical strains) in human alveolar macrophages. The contribution of phagosome acidification, nitric oxide (NO) production and cell dead on NTM intracellular fate was assessed.
View Article and Find Full Text PDFIntroduction: Adenoids are nasopharyngeal lymphoid tissue with a relevant role in host defence against infection of upper respiratory tract. Nevertheless, adenoids are also a reservoir of microorganisms that can cause infections of upper respiratory tract and otitis particularly in children.
Objective: Evaluate and compare the association between biofilm assembly on adenoids and the incidence of recurrent infections in a paediatric population submitted to adenoidectomy by either infectious or non-infectious indication.
In Europe, the mean incidence of urinary tract infections in intensive care units is 1.1 per 1000 patient-days. Of these cases, catheter-associated urinary tract infections (CAUTI) account for 98%.
View Article and Find Full Text PDFTuberculosis (TB) remains a major health problem within the Community of Portuguese Language Speaking Countries (CPLP). Despite the marked variation in TB incidence across its member-states and continued human migratory flux between countries, a considerable gap in the knowledge on the Mycobacterium tuberculosis population structure and strain circulation between the countries still exists. To address this, we have assembled and analysed the largest CPLP M.
View Article and Find Full Text PDFStaphylococcus aureus is a major pathogen in bone associated infections due to its ability to adhere and form biofilms on bone and/or implants. Moreover, recrudescent and chronic infections have been associated with S. aureus capacity to invade and persist within osteoblast cells.
View Article and Find Full Text PDFPolycyclic aromatic hydrocarbons (PAHs) are persistent pollutants present in the environment with known mutagenic and carcinogenic properties. In the present study the effects of exposure to single or multiple doses of benzo[a]anthracene (BaA), pyrene (Pyr), and 3 halogenated derivatives of these compounds (1-chloropyrene, 1-bromopyrene [1-BrPyr], and 7-chlorobenzo[a]anthracene [7-ClBaA]) were evaluated in a liver-derived human cell line (HepG2). Cytotoxicity as assessed by the classic 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and neutral red assays showed a mild toxic effect in response to single or multiple dose exposure for up to 72 h, except for multiple dose exposure to BaA and 7-ClBaA (1 μM/d for 4 d) and single exposure to 10 μM BaA.
View Article and Find Full Text PDFis a prominent etiological agent of healthcare associated infections (HAIs). In this context, multidrug-resistant and biofilm-producing bacteria are of special public health concern due to the difficulties associated with treatment of human infections and eradication from hospital environments. Here, in order to study the impact of medical devices-associated materials on the biofilm dynamics, we performed biofilm phenotypic analyses through a classic and a new scanning electron microscopy (SEM) technique for three multidrug-resistant isolates growing on polystyrene and silicone.
View Article and Find Full Text PDFAdenoids play a key role in both respiratory and ear infection in children. It has also been shown that adenoidectomy improves these symptoms in this population. The main goal of the present study was to evaluate adenoid bacterial colonization and document a possible relation with infectious respiratory disease.
View Article and Find Full Text PDFIn parks, ornamental waters of easy access and populated with animals are quite attractive to children and yet might hide threats to human health. The present work focuses on the microbiota of the ornamental waters of a Lisboa park, characterized during 2015. The results show a dynamic microbiota integrating human pathogens such as Klebsiella pneumoniae, Aeromonas spp.
View Article and Find Full Text PDFNontuberculous mycobacteria (NTM) are emergent pathogens whose importance in human health has been gaining relevance after being recognized as etiological agents of opportunist infections in HIV patients. Currently, NTM are recognized as etiological agents of several respiratory and extra-respiratory infections of immune-competent individuals. The environmental nature of NTM together with the ability to assemble biofilms on different surfaces plays a key role on their pathogenesis.
View Article and Find Full Text PDFNontuberculous mycobacteria (NTM) are emergent pathogens whose importance in human health has been growing. After being regarded mainly as etiological agents of opportunist infections in HIV patients, they have also been recognized as etiological agents of several infections on immune-competent individuals and healthcare-associated infections. The environmental nature of NTM and their ability to assemble biofilms on different surfaces play a key role in their pathogenesis.
View Article and Find Full Text PDFHealthcare-associated infections (HAI) are a huge public health concern, particularly when the etiological agents are multidrug resistant. The ability of bacteria to develop biofilm is a helpful skill, both to persist within hospital units and to increase antibiotic resistance. Although the links between antibiotic resistance, biofilms assembly and HAI are consensual, little is known about biofilms.
View Article and Find Full Text PDFBackground: Multidrug- (MDR) and extensively drug resistant (XDR) tuberculosis (TB) presents a challenge to disease control and elimination goals. In Lisbon, Portugal, specific and successful XDR-TB strains have been found in circulation for almost two decades.
Results: In the present study we have genotyped and sequenced the genomes of 56 Mycobacterium tuberculosis isolates recovered mostly from Lisbon.
Multidrug tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) cases constitute a serious health problem in Portugal, of which the majority of isolates belong to the Lisboa family and the Q1 cluster, highly related to the Lisboa family. Here we sought to investigate the molecular basis of resistant TB as well as to determine the prevalence of specific drug resistance mutations and their association with MDR-TB and/or XDR-TB. In total, 74 Mycobacterium tuberculosis clinical isolates collected in Lisbon Health Region were genotyped by 24-loci mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR), and the mutational profile associated with first- and second-line drug resistance was studied.
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