Interaction between non-disease causing microorganism and E. coli in catheter-associated urinary tract biofilms

Most biofilms involved in catheter-associated urinary tract infections (CAUTIs) are polymicrobial, with disease causing (e.g. E. coli) and non-disease causing (NDC) microorganisms (Delftia tsuruhstensis, Achromobacter xylosoxidans, Burkholderia fungorum) frequently co-inhabiting the same catheter. Nevertheless, there is a lack of knowledge about the role that NDC microorganisms have on biofilm formation by E. coli. This information is essential for a better understanding of CAUTIs etiology. As such, single- and dual-species biofilms were formed in 96-well microtiter plates, using artificial urine medium (AUM). Biofilm quantification was evaluated by crystal violet staining, CFU counts and DAPI counts at 24h, 48h, 96h and 192h. In single-species biofilms, results showed that all species were able to form biofilms (Log 5.84-7.25 CFUs.cm2 at 192h). Concerning dual species biofilms, E. coli appears to have a negative impact on the ability of the NDC species to form biofilms, but, NDC species do not seem to influence E. coli when the two species start forming the biofilm simultaneously and at the same concentration. In fact, the growth rate of E. coli (0.4564 h-1) in AUM is higher than the growth rates of NDC microorganisms (0.0458 h-1–0.131 h-1). Additionally, in dual-species biofilms with an E. coli pre-formed biofilm, the E. coli seems to prevail, even in conditions with a low initial inoculum concentration (102 CFUs.ml-1 vs. 108 CFUs.ml-1 for NDC microorganisms). In conclusion, E. coli has a greater ability to form biofilm in conditions mimicking the CAUTIs, which helps explain why E. coli is the most prevalent agent in CAUTIs

Impact of polymicrobial biofilms in catheter-associated urinary tract infections

Recent reports have demonstrated that most biofilms involved in catheter-associated urinary tract infections are polymicrobial communities, with pathogenic microorganisms (e.g. Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) and uncommon microorganisms (e.g. Delftia tsuruhatensis, Achromobacter xylosoxidans) frequently co-inhabiting the same urinary catheter. However, little is known about the interactions that occur between different microorganisms and how they impact biofilm formation and infection outcome. This lack of knowledge affects CAUTIs management as uncommon bacteria action can, for instance, influence the rate at which pathogens adhere and grow, as well as affect the overall biofilm resistance to antibiotics. Another relevant aspect is the understanding of factors that drive a single pathogenic bacterium to become prevalent in a polymicrobial community and subsequently cause infection. In this review, a general overview about the IMDs-associated biofilm infections is provided, with an emphasis on the pathophysiology and the microbiome composition of CAUTIs. Based on the available literature, it is clear that more research about the microbiome interaction, mechanisms of biofilm formation and of antimicrobial tolerance of the polymicrobial consortium are required to better understand and treat these infections.This work was financially supported by: Project POCI-010145-FEDER-006939 – Laboratory for Process Engineering, Environment, Biotechnology and Energy – LEPABE funded by FEDER funds through COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI) – and by national funds through FCT – Fundacao para a Ci^encia e a Tecnologia; Project “DNAmimics” [PIC/IC/82815/2007]; PhD fellowships [SFRH/BD/82663/2011].info:eu-repo/semantics/publishedVersio

The mechanism of aquaporin inhibition by gold compounds elucidated by biophysical and computational methods

The inhibition of water and glycerol permeation via human aquaglyceroporin-3 (AQP3) by gold(III) complexes has been studied by stopped-flow spectroscopy and, for the first time, its mechanism has been described using molecular dynamics (MD), combined with density functional theory (DFT) and electrochemical studies. The obtained MD results showed that the most effective gold-based inhibitor, anchored to Cys40 in AQP3, is able to induce shrinkage of pores preventing glycerol and water permeation. Moreover, the good correlation between the affinity of the Au(III) complex to Cys binding and AQP3 inhibition effects was highlighted, while no influence of the different oxidative character of the complexes could be observed

Calibration of infusion pumps using liquids whose physical properties differ from those of water

Infusion medical devices are used in field applications, namely in clinical environments, here are used several types of liquids, according to the therapeutic to be administrated into the patient. In order to determine the influence of the fluids physical properties, such as viscosity and density and to produce an adequate reference liquid, tests were performed with a syringe pump, using the gravimetric method as reference calibration method.publishersversionpublishe

Impact of Delftia tsuruhatensis and Achromobacter xylosoxidans on Escherichia coli dual-species biofilms treated with antibiotic agents

Recently it was demonstrated that for urinary tract infections species with a lower or unproven pathogenic potential, such as Delftia tsuruhatensis and Achromobacter xylosoxidans, might interact with conventional pathogenic agents such as Escherichia coli. Here, single- and dual-species biofilms of these microorganisms were characterized in terms of microbial composition over time, the average fitness of E. coli, the spatial organization and the biofilm antimicrobial profile. The results revealed a positive impact of these species on the fitness of E. coli and a greater tolerance to the antibiotic agents. In dual-species biofilms exposed to antibiotics, E. coli was able to dominate the microbial consortia in spite of being the most sensitive strain. This is the first study demonstrating the protective effect of less common species over E. coli under adverse conditions imposed by the use of antibiotic agents.This work was financially supported by the FCT/MEC with national funds and when applicable co-funded by FEDER in the scope of the P2020 Partnership Agreement [Project UID/ EQU/00511/2013-LEPABE]; FEDER funds through the Operational Programme for Competitiveness Factors – COMPETE, O Novo Norte–North Portugal Regional Operational Programme – ON2 and National Funds through Foundation for Science and Technology – FCT [Project NORTE-07-0124- FEDER-000025–RL2_ Environment&Health and Project ‘DNAmimics’ PIC/IC/82815/2007]; PhD fellowship [SFRH/ BD/82663/2011]; and postdoctoral fellowship [SFRH/ BPD/74480/2010]

Interaction between atypical microorganisms and E. coli in catheter-associated urinary tract biofilms

Most biofilms involved in catheter-associated urinary tract infections (CAUTIs) are polymicrobial, with disease causing (eg Escherichia coli) and atypical microorganisms (eg Delftia tsuruhatensis) frequently inhabiting the same catheter. Nevertheless, there is a lack of knowledge about the role of atypical microorganisms. Here, single and dual-species biofilms consisting of E. coli and atypical bacteria (D. tsuruhatensis and Achromobacter xylosoxidans), were evaluated. All species were good biofilm producers (Log 5.84–7.25 CFU cm−2 at 192 h) in artificial urine. The ability of atypical species to form a biofilm appeared to be hampered by the presence of E. coli. Additionally, when E. coli was added to a pre-formed biofilm of the atypical species, it seemed to take advantage of the first colonizers to accelerate adhesion, even when added at lower concentrations. The results suggest a greater ability of E. coli to form biofilms in conditions mimicking the CAUTIs, whatever the pre-existing microbiota and the inoculum concentration.This work was supported by the Portuguese Science Foundation (FCT), DNA mimics Research Project [Ref. PIC/IC/82815/2007] from the FCT and MCTES; PhD Fellowship [SFRH/BD/82663/2011]; and Postdoctoral Fellowship [SFRH/BPD/74480/2010]. The authors would like to thank to M. Fenice M and A. Steinbuchel for kindly providing the Delftia tsuruhatensis BM90 and Achromobacter xylosoxidans B3 species, respectively

A viewpoint on the use of microalgae as an alternative feedstuff in the context of pig and poultry feeding - a special emphasis on tropical regions

With the current increase in meat and animal products consumption, there is a need to make production systems more sustainable. The use of microalgae in monogastric feeds, replacing widely used conventional feedstuffs such corn and soybean, can be a solution to overcome this problem. Several studies have shown promising results in the use of microalgae in feeding of both pigs and poultry. However, there are several important constraints associated to the production of microalgae. Such constraints are particularly limiting in the context of tropical regions. Research and scientific development on microalgae production systems are thus essential so that may be widely used in monogastric feeding. Herein, we conduct an overview of the major findings in the use of microalgae in the context of monogastric feeding and analyse the major constraints associated to its production and use, particularly in the specific context of tropical regions.info:eu-repo/semantics/submittedVersio

Cooperation or conflict? Impact of intraspecific diversity on Escherichia coli biofilms

Intraspecific diversity in biofilm communities is associated with enhanced survival and growth of the individual biofilm populations. In here, we assess if this apparent cooperative behavior still holds as the number of different strains in a biofilm increases. Using E. coli as a model organism, the influence of intraspecific diversity in biofilm populations composed of up to six different E. coli strains, was assessed. Biofilm quantification was evaluated by crystal violet (CV) staining and colony forming units (CFU) counts. In general, with the increasing number of strains in a biofilm, an increase in cell counts and a decrease in matrix production was observed. This observation was confirmed by cluster analysis that indicated that after 24h of biofilm formation the best model, according to the Bayesian information criterion (BIC), consisted of three clusters that grouped together biofilms with an equal number of strains. It hence appears that increased genotypic diversity in a biofilm leads E. coli to maximize the production of its offspring, in detriment of the production of public goods (i.e. matrix components), that would be beneficial to all strains individually and the consortium as a whole. Apart from the ecological implications, these results can be explored in the area of clinical biofilms, as a decrease in matrix production might render these intraspecies biofilms more sensitive to antimicrobial agents

Increased intraspecies diversity in Escherichia coli biofilms promotes cellular growth at the expense of matrix production

Intraspecies diversity in biofilm communities is associated with enhanced survival and growth of the individual biofilm populations. Studies on the subject are scarce, namely, when more than three strains are present. Hence, in this study, the influence of intraspecies diversity in biofilm populations composed of up to six different Escherichia coli strains isolated from urine was evaluated in conditions mimicking the ones observed in urinary tract infections and catheter-associated urinary tract infections. In general, with the increasing number of strains in a biofilm, an increase in cell cultivability and a decrease in matrix production were observed. For instance, single-strain biofilms produced an average of 73.1 µg·cm−2 of extracellular polymeric substances (EPS), while six strains biofilms produced 19.9 µg·cm−2. Hence, it appears that increased genotypic diversity in a biofilm leads E. coli to direct energy towards the production of its offspring, in detriment of the production of public goods (i.e., matrix components). Apart from ecological implications, these results can be explored as another strategy to reduce the biofilm burden, as a decrease in EPS matrix production may render these intraspecies biofilms more sensitive to antimicrobial agents.This work was financially supported by Base Funding—UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology and Energy—LEPABE—funded by national funds through the FCT/MCTES (PIDDAC); Project POCI-01-0145-FEDER-030431 (CLASInVivo) and project POCI-01-0145-FEDER-029841 (POLY-PREVENTT), funded by FEDER funds through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI) and by national funds (PIDDAC) through FCT/MCTES; Strategic funding of UIDB/04469/2020 of the Centre of Biological Engineering–CEB–funded by national funds through the FCT; Project BeMundus Brazil Europe/Erasmus Mundus scholarship granted by BM13DF0014.info:eu-repo/semantics/publishedVersio