Detection and Molecular Characterization of Rotavirus Infections in Children and Adults with Gastroenteritis from Vojvodina, Serbia.

Rotaviruses (RV) are the leading cause of gastroenteritis in infants, young children, and adults, responsible for serious disease burden. In the period 2012-2018, a cross-sectional study was conducted using stool samples collected from patients with acute gastroenteritis from Vojvodina, Serbia. We described age and gender distribution, as well as seasonal patterns of RV prevalence. Out of 1853 included stool samples, RV was detected in 29%. Hospitalized children between 1-2 years old were especially affected by RV infection (45%). The highest prevalence of infection was observed during the colder, winter/spring months. We compared sequenced representative G and P genotypes circulating in Serbia with vaccine strains and determined their genetic similarity. Genotype combination G2P[4] was the most prevalent (34.6%), followed by G2P[8] (24.1%) and G1P[8] (21.1%). Given that several epitopes were conserved, neutralization motifs among circulating strains can be characterized as sufficiently matching vaccine strains Rotarix™ and RotaTeq™, but existing antigenic disparities should not be overlooked. The present results contribute to a better insight into the prevalence of rotavirus infection in our region and point out the need for epidemiological surveillance of rotaviruses before the introduction of vaccines. These data can help formulate future vaccine strategies in Serbia.

Pneumococcal carriage in adults aged 50 years and older in outpatient health care facility during pandemic COVID-19 in Novi Sad, Serbia.

BACKGROUND: Data related to carriage of Streptococcus pneumoniae (Spn) and antimicrobial resistance patterns in middle-aged and older adults are limited. We assessed the carriage of Spn, and its antibiotic resistance patterns, among participants ≥50 years of age living in the city of Novi Sad during the second year of COVID-19 pandemic. METHODS: Analysis of prospectively collected data among participants with or without symptoms of upper respiratory tract infection who visited their elected physicians in the Primary Health Care Centre of Novi Sad (outpatient facility) was conducted from May 18, 2021 to December 7, 2021. Both nasopharyngeal (NP) and oropharyngeal (OP) samples from each participant were collected. RESULTS: A total of 1042 samples from 521 study subjects (1 NP and 1 OP sample from each person) were collected. Sixteen samples from the same number of persons (3.1%, 95% confidence interval: 1.76%-4.94%) were culture positive for the presence of Spn. Overall, the median age of study participants was 71 years (range, 50-93 years; 90th percentile, 77 years), and most (197/521, 37.8%) of them were 70-79 years of age. A majority of the study subjects were: females (324/521; 62.2%), sampled during May and June 2021 (376/521, 72.2%), those who did not have contact with children aged 0-10 years in the family (403/521; 77.4%), without smokers in the household (443/521; 85.0%), and those who did not receive vaccine against Spn (519/521; 99.6%). Out of 16 Spn positive samples, for six participants, Spn carriage serotypes were obtained and there were four vaccine (6A, 11A, 15B, and 18C) serotypes, and two (6C and 35F) non-vaccine serotypes. Remaining 10 (62.50%) samples were non-typeable isolates of pneumococci. Among four vaccine serotypes, two (6A and 18C) were represented in PCV13, and 18C along with the other two (11A and 15B) in PPSV23 vaccine. The highest level of resistance of Spn isolates was observed for erythromycin, (10 or 62.50%), and tetracycline, (7 or 43.75%), one isolate showed resistance to penicillin, ampicillin, and amoxicillin/amoxicillin-clavulanic acid, while none of them were resistant to ceftriaxone, trimethoprim/sulfamethoxazole and levofloxacin. There were three multi-drug resistant isolates; one was identified as 6C (non-vaccine serotype), and two other were non-typeable isolates of Spn. CONCLUSIONS: In this first study conducted in Serbia on Spn carriage in adults ≥50 years of age, we found low prevalence of Spn carriage and identified 6 serotypes of Spn, four of which were represented in vaccines. These results may support future Spn colonization studies among middle-aged and older adults.

Colicins and Microcins Produced by Enterobacteriaceae: Characterization, Mode of Action, and Putative Applications.

Enterobacteriaceae are widely present in many environments related to humans, including the human body and the food that they consume, from both plant or animal origin. Hence, they are considered relevant members of the gastrointestinal tract microbiota. On the other hand, these bacteria are also recognized as putative pathogens, able to impair human health and, in food, they are considered indicators for the microbiological quality and hygiene status of a production process. Nevertheless, beneficial properties have also been associated with Enterobacteriaceae, such as the ability to synthesize peptides and proteins, which can have a role in the structure of microbial communities. Among these antimicrobial molecules, those with higher molecular mass are called colicins, while those with lower molecular mass are named microcins. In recent years, some studies show an emphasis on molecules that can help control the development of pathogens. However, not enough data are available on this subject, especially related to microcins. Hence, this review gathers and summarizes current knowledge on colicins and microcins, potential usage in the treatment of pathogen-associated diseases and cancer, as well as putative applications in food biotechnology.

Pneumococcal nasopharyngeal carriage in children under 5 years of age at an outpatient healthcare facility in Novi Sad, Serbia during the COVID-19 pandemic.

Objectives: To assess whether pneumococcal nasopharyngeal carriage among children aged 24-60 months reduced during the coronavirus disease 2019 (COVID-19) pandemic in Novi Sad, Serbia, and to investigate the overall prevalence of carriage, serotype distribution and dominant serotypes 2-3 years after the introduction of pneumococcal conjugate vaccine 10. Design and methods: This prospective, observational study was conducted in February-March 2020, September-November 2020 and April-June 2021, enabling the comparison of results in the pre-pandemic/early pandemic period with two periods during the COVID-19 pandemic. Pneumococci were identified by standard microbiological methods. Serotype identification was performed using conventional multiplex polymerase chain reaction assays. Results: Among 1623 children tested, 515 (31.7%, 95% confidence interval 29.4-34.0%) carried pneumococci. A significant increase in prevalence was found between February-March 2020 and September-November 2020 (P=0.0085), with no difference found between September-November 2020 and April-June 2021 (P=0.0524). Pneumococcal colonization was significantly higher in children who were fully vaccinated and among children who attended day care centres. The dominant serotypes were 15B, 6B, 19F, 11A, 6C, 6A, 3, 23F and 19A, representing 66.4% of all isolates. Conclusions: This study found that pneumococcal nasopharyngeal carriage in children aged 24-60 months was high before the COVID-19 pandemic, and then increased during the pandemic. This rules out a major role of COVID-19 in the suppression of carriage and, probably, transmission.

Analysis of patient-specific stimulation with segmented leads in the subthalamic nucleus.

OBJECTIVE: Segmented deep brain stimulation leads in the subthalamic nucleus have shown to increase therapeutic window using directional stimulation. However, it is not fully understood how these segmented leads with reduced electrode size modify the volume of tissue activated (VTA) and how this in turn relates with clinically observed therapeutic and side effect currents. Here, we investigated the differences between directional and omnidirectional stimulation and associated VTAs with patient-specific therapeutic and side effect currents for the two stimulation modes. APPROACH: Nine patients with Parkinson's disease underwent DBS implantation in the subthalamic nucleus. Therapeutic and side effect currents were identified intraoperatively with a segmented lead using directional and omnidirectional stimulation (these current thresholds were assessed in a blinded fashion). The electric field around the lead was simulated with a finite-element model for a range of stimulation currents for both stimulation modes. VTAs were estimated from the electric field by numerical differentiation and thresholding. Then for each patient, the VTAs for given therapeutic and side effect currents were projected onto the patient-specific subthalamic nucleus and lead position. RESULTS: Stimulation with segmented leads with reduced electrode size was associated with a significant reduction of VTA and a significant increase of radial distance in the best direction of stimulation. While beneficial effects were associated with activation volumes confined within the anatomical boundaries of the subthalamic nucleus at therapeutic currents, side effects were associated with activation volumes spreading beyond the nucleus' boundaries. SIGNIFICANCE: The clinical benefits of segmented leads are likely to be obtained by a VTA confined within the subthalamic nucleus and a larger radial distance in the best stimulation direction, while steering the VTA away from unwanted fiber tracts outside the nucleus. Applying the same concepts at a larger scale and in chronically implanted patients may help to predict the best stimulation area.

Influenza B Viruses in the Population of Province of Vojvodina during the 2012/2013 Season: Differentiation of B/Yamagata and B/Victoria Lineages by Real-time RT-PCR, Antigenic and Phylogenetic Characterization.

INTRODUCTION: At present, two phylogenetically distinct influenza B virus lineages, B/Yamagata and B/ Victoria, co-circulate worldwide and can cause significant morbidity and mortality. OBJECTIVE: The aim of this study was to determine the prevalences of two influenza B virus lineages in the population of Vojvodina and to identify their antigenic and phylogenetic properties. METHODS: A total of 369 and 334 nasopharyngeal, or nasal/throat swab samples, collected during the 2012/2013 and 2013/2014 seasons, respectively, were tested using specific singleplex influenza A, influenza B, influenza B/Yamagata and influenza B/Victoria real-time reverse transcription polymerase chain reaction (RT-PCR) assays. Antigenic and genetic testing were done by hemagglutination inhibition assay and hemagglutinin and neuraminidase gene sequence analysis, respectively. RESULTS: During the 2012/2013 season, influenza B viruses were present in 53.4% (101/189) of influenza positive samples.The B/Yamagata-like viruses (81.2%) significantly predominated over the B/Victoria-like viruses (18.8%). Comparing to B/Victoria-like positive patients, among B/Yamagata-like positive patients, children 5-14 years of age were significantly more represented (5.3% vs. 35.4%, respectively), as well as patients with mild form of illness (15.8% vs. 45.1%, respectively). The results of sequence analysis and antigenic testing showed that tested viruses were not closely related to B/Wisconsin/1/2010, the vaccine virus for 2012/2013. During the 2013/2014 season influenza B viruses were not detected. CONCLUSION: The results of this study confirmed the health significance of influenza B viruses and indicated that B/Yamagata-like viruses were significantly more prevalent than B/Victoria lineage viruses, during the 2012/2013 season. They also showed a sub-optimal match between the tested viruses and the vaccine virus for season 2012/2013.

Synthetic 3D diamond-based electrodes for flexible retinal neuroprostheses: Model, production and in vivo biocompatibility.

Two retinal implants have recently received the CE mark and one has obtained FDA approval for the restoration of useful vision in blind patients. Since the spatial resolution of current vision prostheses is not sufficient for most patients to detect faces or perform activities of daily living, more electrodes with less crosstalk are needed to transfer complex images to the retina. In this study, we modelled planar and three-dimensional (3D) implants with a distant ground or a ground grid, to demonstrate greater spatial resolution with 3D structures. Using such flexible 3D implant prototypes, we showed that the degenerated retina could mould itself to the inside of the wells, thereby isolating bipolar neurons for specific, independent stimulation. To investigate the in vivo biocompatibility of diamond as an electrode or an isolating material, we developed a procedure for depositing diamond onto flexible 3D retinal implants. Taking polyimide 3D implants as a reference, we compared the number of neurones integrating the 3D diamond structures and their ratio to the numbers of all cells, including glial cells. Bipolar neurones were increased whereas there was no increase even a decrease in the total cell number. SEM examinations of implants confirmed the stability of the diamond after its implantation in vivo. This study further demonstrates the potential of 3D designs for increasing the resolution of retinal implants and validates the safety of diamond materials for retinal implants and neuroprostheses in general.

[Restoring vision in blind patients following photoreceptor degeneration: clinical results and future challenges]. / Restaurer la vision de patients aveugles avec des prothèses rétiniennes : Résultats cliniques et défis futurs.

Retinal prostheses aim at restoring vision in patients blind from photoreceptor degeneration by electrically stimulating the residual retinal tissue. Currently, the most efficient implants are either inserted in the subretinal space or on the vitreal side of the retina (epi-retinal). Although the residual tissue can partly degenerate, it was shown that acute stimulation of residual neurones can induce visual percepts. Recently, a clinical trial with the epiretinal Argus2 device (60 electrodes) from the company 2nd Sight enabled most patients to orient and find light targets, some even reading words. This device has received a CE mark. Surprisingly, when the subretinal implant from the company Retina Implant AG displaying many more electrodes (1500 electrodes) was evaluated in clinical trials, the patient visual performances were fairly similar. The restored visual performances of the patients demonstrate that blind patients can recover some visual function when their residual retina is properly stimulated. However, the resolution is not yet sufficient to perform complex tasks such as autonomous locomotion, face identification or text reading. Several challenges remain to generate an increase in pixel density corresponding to the increase in electrode number and density. These challenges include the stimulation modality, the tissue/implant interface design, the electrode materials, and the visual information encoder. This review will discuss these great challenges after introducing the major clinical results.

Long-term in vivo impedance changes of subretinal microelectrodes implanted in dystrophic P23H rats.

Retinal prostheses are being developed to restore vision in blind patients with photoreceptor degeneration. Electrodes arrays were subretinally implanted in transgenic P23H rats with their photoreceptors degenerated. Electrical stability of the implants was evaluated by long-term monitoring of their impedance changes. Electrode impedances were found to increase by two log units over a three weeks period whereas no impedance increase was noted when the implants were located in the vitreous. In case of hemorrhage or major fibrous reactions, the impedance continued to increase steadily. After explantation, it recovered its initial value indicating no deterioration of the implant. Although the glial cell layer at the surface of the subretinal space was slightly larger, no major glial reaction was seen in direct contact to the implant. These results indicate that no functional testing should be considered before at least three weeks post implantation.

Point-process analysis of neural spiking activity of muscle spindles recorded from thin-film longitudinal intrafascicular electrodes.

Recordings from thin-film Longitudinal Intra-Fascicular Electrodes (tfLIFE) together with a wavelet-based de-noising and a correlation-based spike sorting algorithm, give access to firing patterns of muscle spindle afferents. In this study we use a point process probability structure to assess mechanical stimulus-response characteristics of muscle spindle spike trains. We assume that the stimulus intensity is primarily a linear combination of the spontaneous firing rate, the muscle extension, and the stretch velocity. By using the ability of the point process framework to provide an objective goodness of fit analysis, we were able to distinguish two classes of spike clusters with different statistical structure. We found that spike clusters with higher SNR have a temporal structure that can be fitted by an inverse Gaussian distribution while lower SNR clusters follow a Poisson-like distribution. The point process algorithm is further able to provide the instantaneous intensity function associated with the stimulus-response model with the best goodness of fit. This important result is a first step towards a point process decoding algorithm to estimate the muscle length and possibly provide closed loop Functional Electrical Stimulation (FES) systems with natural sensory feedback information.

Spike sorting of muscle spindle afferent nerve activity recorded with thin-film intrafascicular electrodes.

Afferent muscle spindle activity in response to passive muscle stretch was recorded in vivo using thin-film longitudinal intrafascicular electrodes. A neural spike detection and classification scheme was developed for the purpose of separating activity of primary and secondary muscle spindle afferents. The algorithm is based on the multiscale continuous wavelet transform using complex wavelets. The detection scheme outperforms the commonly used threshold detection, especially with recordings having low signal-to-noise ratio. Results of classification of units indicate that the developed classifier is able to isolate activity having linear relationship with muscle length, which is a step towards online model-based estimation of muscle length that can be used in a closed-loop functional electrical stimulation system with natural sensory feedback.

Interpretation of muscle spindle afferent nerve response to passive muscle stretch recorded with thin-film longitudinal intrafascicular electrodes.

In this study, we explored the feasibility of estimating muscle length in passive conditions by interpreting nerve responses from muscle spindle afferents recorded with thin-film longitudinal intrafascicular electrodes. Afferent muscle spindle response to passive stretch was recorded in ten acute rabbit experiments. A newly proposed first-order model of muscle spindle response to passive sinusoidal muscle stretch manages to capture the relationship between afferent neural firing rate and muscle length. We demonstrate that the model can be used to track random motion trajectories with bandwidth from 0.1 to 1 Hz over a range of 4 mm with a muscle length estimation error of 0.3 mm (1.4 degrees of joint angle). When estimation is performed using four-channel ENG there is a 50% reduction in estimate variation, compared to using single-channel recordings.