3D Printed Microfluidic Bioreactors Used for the Preferential Growth of Bacterial Biofilms through Dielectrophoresis.

A realistic modelling of the way biofilms form and evolve in time requests a dynamic approach. In this study, the proposed route uses continuous-flow bioreactors under controlled flow rates and temperature in the culture medium containing bacteria or fungi. 3D printed, Polylactic acid (PLA), flow-based bioreactors with integrated copper electrodes were used to investigate the effect of dielectrophoresis on the formation and growth of Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 27853, and Klebsiella pneumoniae ATCC 13883 biofilms. Bacterial suspensions of 1McF turbidity have been prepared and circulated through the bioreactors. At the same time, a 30 V potential difference was applied on the system. The effect of the non-uniform electric field induced upon the bacterial cells was determined using quantitative methods, such as an adjusted microtiter plate technique, as well as spectral domain optical coherence tomography (SD-OCT) images. The morphology and the surface quality of the biofilms were investigated using Scanning Electron Microscopy (SEM) images. The results show that the different bacterial cells present a positive dielectrophoretic behaviour, with the preferential formation of biofilms in the high field gradient region.

When a Ciliate Meets a Flagellate: A Rare Case of Colpoda spp. and Colpodella spp. Isolated from the Urine of a Human Patient. Case Report and Brief Review of Literature.

An often-overlooked side of the population aging process and the steady rise of non-communicable diseases reflects the emergence of novel infectious pathogens on the background of an altered host immune response. The aim of this article was to present the first record of a ciliate and flagellate protozoa recovered from the urine of an elderly patient and to review the existing medical literature involving these parasites. A 70-year-old female patient was admitted for breathing difficulties on the basis of an acute exacerbation of COPD (Chronic obstructive pulmonary disease) with respiratory insufficiency. The patient reported a long history of multiple comorbidities including COPD Gold II, chronic respiratory insufficiency, chronic heart failure NYHA III (New York Heart Association Functional Classification), type 2 diabetes and morbid obesity. During routine examinations, we ascertained the presence of two unusual protozoa, a ciliate and a flagellate, in the patient's urine samples, identified on morphological criteria to be most likely Colpoda spp. and Colpodella spp., with similarities to C. steinii and C. gonderi. The presence of these parasites was not associated with any clinical signs of urinary disease. Following a combined treatment with ceftriaxone and metronidazole, we observed the disappearance of these pathogens upon discharge from the primary care clinic. This study highlights the importance of including unusual pathogens in the differential diagnosis of cases which involve immunosuppression.