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

Rapid detection of microorganisms by peptide nucleic acids

Peptide nucleic acid (PNA) molecules are DNA mimics, where the negatively charged sugarphosphate backbone is replaced by an achiral, neutral polyamide backbone formed by repetitive units of N–(2-aminoethyl) glycine. Due to their superior hybridization properties, PNA probes to detect pathogens by fluorescence in situ hybridization (FISH) have been challenging DNA probes over the last few years. In our lab, we have already designed and developed several new probes for the specific detection of bacterial species such as Helicobacter pylori, Cronobacter spp., Staphylococcus epidermidis, Salmonella spp. and Proteus spp. [1, 2]. During development and validation, probes are tested against several related species, and have been shown to be highly specific for the microorganisms of interest. All techniques were optimized in slides and then adapted for different types of samples, depending on the microorganism: H. pylori probe has been developed to work on gastric biopsies and will soon be tested in a clinical trial for a potentially commercial application; Cronobacter spp. is a major contaminant of milk-based powdered infant formula, and as such a probe to detect the pathogen after pre-enrichment of contaminated milk was devised; S. epidermidis, which is frequently present on the skin of humans, had methods developed for its identification in blood samples and catheters; and analysis of interest for Salmonella and Proteus spp. included pipes of drinking water distribution systems and urinary samples. Future work with PNA probes will involve simultaneous detection of several species in a single sample and quantitative signal detection by flow cytometry

Detection and discrimination of microorganisms using Locked Nucleic Acid - Fluorescence In Situ Hybridization (LNA-FISH)

The impact of multispecies biofilms on catheter-associated urinary tract infections outcome is still unclear due to the lack of adequate methodologies to discriminate the populations in situ. Employing fluorescence in situ hybridization (FISH) to discriminate the populations in a biofilm, can contribute to the understanding of microorganisms interactions in this structures. Consequently, this information might help to develop efficient strategies to prevent this disease. This work presents the first study that apply the FISH methodology using a set of LNA and/2’-O-Methyl RNA oligonucleotide probes, for the in situ detection of microorganisms in biofilms formed under conditions similar to the catheter-associated urinary tract infections

Analysis of Seawater Electrolysis Technologies for Green Hydrogen Production

Trabalho apresentado em 1st International Conference on Challenges in Engineering, Medical, Economics and Education: Research & Solutions (CEMEERS-23), June 21-22 2023, Lisbon, PortugalThe main goal of this study is to understand the technical and economic feasibility of installing and operating a seawater desalination plant to supply water to a GW-scale water electrolysis process. That hydrogen production facility should be powered by dedicated renewable energy sources such as wind and solar photovoltaic. The announcement of significant investments in hydrogen production in the Sines region makes it relevant to perform a detailed analysis of the operation of this type of system that will present challenges with regards to the electricity and water supply. Water, in particular freshwater, is a scarce resource in the south of Portugal and the installation of an industry that uses large amounts of water as feedstock can place considerable pressure on existing reserves. Given the proximity of the region to the Atlantic Ocean, it is appropriate to evaluate the installation of a desalination plant and analyze the overall impact of that option on hydrogen production. The levelized cost of desalinated water is estimated and compared to the cost of grid water. It has been found that the levelized cost of desalinated water is lower than the price of potable water supplied to the local industries by the Sines municipal water service (Águas de Santo André). The impact on the levelized cost of hydrogen is analyzed. It is shown that the installation and operation of the desalination unit increases the levelized cost of hydrogen by less than 1%. Seawater desalination is shown to be a technically viable alternative for producing the water feedstock for a GW- scale electrolysis facility that could alleviate pressure on local freshwater sourcesinfo:eu-repo/semantics/publishedVersio

Impact of hypoxic and anaerobic environments on multidrug-resistance of emerging species found in cystic fibrosis airways

OBJECTIVES: It is well-known the establishment of steep oxygen gradients in cystic fibrosis (CF) airways mucus, giving rise to hypoxic or anaerobic zones in the deeper mucus layers, where traditional and atypical bacteria may accommodate and proliferate to biofilms. This study aimed to compare the influence of low-oxygen atmospheres on biofilm growth and susceptibility profiles of the CF-atypical species Inquilinus limosus and Dolosigranulum pigrum with the traditional Pseudomonas aeruginosa. METHODS: Single biofilms encompassing each species were formed in vitro under aerobic, micraerophilic and anaerobic environments, and further evaluated in terms of biomass and respiratory activity. The antibiotic resistance propensity of planktonic and biofilm-cells was also analyzed by measuring the MICs and MBECs, respectively. RESULTS: Both traditional and unusual species were proficient to develop biofilms under all oxygen environments, with the facultative anaerobe D. pigrum demonstrating the greatest facility to accumulate high amounts of biomass and respiratory activities. Regarding the resistance propensity, planktonic populations of P. aeruginosa and D. pigrum showed antibiotic tolerance under non oxygen-restricted environments, reducing their resistance under micraerophilic and anaerobic conditions. Independently of the oxygen availability, it was noticed a markedly decline of the antibiotic action against the pre-established biofilms, requiring higher doses to eliminate biofilm-encased cells. Although the resistance of P. aeruginosa biofilms has displayed the same tendency as the planktonic populations, the biofilm consortia involving I. limosus and D. pigrum became exceptionally more resistant to antibiotics when compared to those bacteria seeded from the biofilms, persevering this multidrug resistance under hypoxic and anaerobic atmospheres. CONCLUSION: This study highlights a potential prospect on the impact of non-conventional organisms on CF lung infections, showing their great capacity to easily adapt to biofilm mode of life under atmospheres with restricted oxygen, as it is believed to occur in CF airways, which may endanger the efficacy of current antibiotic regimens in CF