Journal of Microbiological Methods

Probiotics produce antimicrobial peptides and small molecules that are secreted into the medium. Antimicrobial activity of cell-free supernatants can be tested using various qualitative and quantitative methods. Many of these techniques employ methods which introduce uncontrolled variables, impacting reproducibility and making comparison of reported results difficult. Here, we present a simple procedure for quantitative estimation of antimicrobial activity of cell-free supernatants which overcomes drawbacks of commonly used methods.

Motility of Plasmodium sporozoites (SPZs) in the skin is a key determinant of successful host infection. Earlier studies have described rapid movement of both murine and human SPZs in skin following syringe inoculation. It is typical to classify SPZ trajectories into ``motile'' and ``immotile'' and restrict the analysis of movement patterns to motile SPZs. Because criteria to define motile SPZs are dependent on the study and are often qualitative, it remains unclear if sub-selection of motile tracks introduces biases in characterization of SPZ movement in vivo. We processed imaging data (22 movies) from a recent study of movement of P. falciparum (Pf) and P. yoelii (Py) SPZ in skin. We proposed a novel metric -- maximal spatial spread (MSS or S) --- that is the maximum Euclidean distance between any two recorded positions in a trajectory. We used MSS to classify SPZ trajectories as immotile (S<Sthreshold) or motile (S>Sthreshold) for a given threshold value Sthreshold. Larger Sthreshold values naturally resulted in a smaller fraction of tracks classified as motile, and subsequently, in an increased overall displacement, instantaneous and mean speeds, decreased mean turning angle, and higher initial slopes of the mean squared displacement (MSD) curves. We found that at intermediate values of Sthreshold Pf SPZs had a lower average speed than Py SPZs suggesting that host environment may impact SPZ movement. Both species exhibited a small but statistically significant decline in average speed with time after inoculation but this was also dependent on the Sthreshold value. Our analysis of MSD curves and turning angle distributions suggests that both Pf and Py SPZs undergo correlated random walks -- a type of Brownian walk with short-term superdiffusive displacement. By using a novel methodology of hidden Markov models (moveHMM package in R) we found that SPZ movement is best described by three movement states; however, none of these states corresponded to previously described circling gliding. Taking together, our results suggest that inference of SPZ movement patterns depends on the criteria used to define tracks as motile or immotile. Standardized preprocessing criteria are therefore important when comparing motility across Plasmodium species, experimental time points, or laboratories. Analysis of turning angle distributions and application of hidden Markov models provided additional metrics to quantify distinct modes of SPZ movement in vivo.

The minimum inhibitory concentration (MIC) is a standard measure for describing the lowest effective dose concentration of an antimicrobial compound in clinical practice; yet, conventional assays often require a substantial amount of antimicrobial compound, limiting their use with scarce, purified agents. Here, we describe a simple and reproducible technique to evaluate the MIC for purified compounds with a limited sample size. The protocol describes the MIC steps against a bacterial strain while minimizing the use of reagents and materials. It is helpful for screening purified natural products as antimicrobial agents and in early-stage drug discovery. The protocol adapts standard microplate-based assays for two-fold dilution of the compound, ensuring their applicability in microbiological studies. The MIC value of the standard antibiotic kanamycin against Staphylococcus aureus, Vibrio fischeri, Klebsiella pneumoniae, and Escherichia coli was determined using our method, and was found to be consistent with the conventional broth microdilution method, validating its reliability. Therefore, this method offers a practical and viable solution for antimicrobial drug discovery, addressing the disparity between limited compound availability and comprehensive microbiological assessment of MIC.

BackgroundReliable detection of Salmonella remains a major challenge for public health surveillance and food safety due to the growing diversity of circulating serovars and the limitations of existing molecular targets. This study aimed to identify an optimal molecular target and develop a TaqMan real-time PCR assay for the detection of Salmonella spp. MethodsBased on the results screening for Salmonella genes suitability as molecular markers, a TaqMan real-time PCR assay targeting the hilA gene was developed and validated. Analytical sensitivity, analytical specificity, and performance on bacterial isolates and artificially contaminated food samples were assessed. ResultsAmong all candidate targets, hilA demonstrated the broadest coverage and was detected in all tested Salmonella isolates, including representatives of rare serological groups, whereas invA conventionally used for this pathogen detection, was absent in a subset of strains. The assay exhibited a limit of detection of 100 bacterial cells/mL and 100 fg/L of genomic DNA. No cross-reactivity was observed with DNA from Shigella flexneri, Shigella sonnei, Yersinia pestis, Y. pseudotuberculosis, Y. enterocolitica, Y. kristensenii, Bacillus anthracis, Vibrio cholerae, or Francisella tularensis. The assay successfully detected Salmonella DNA in all artificially contaminated food samples tested. Evaluation using a collection of 25 bacterial isolates demonstrated positive amplification in all 24 confirmed Salmonella strains, while a strain initially identified by conventional bacteriology as Salmonella but subsequently confirmed by whole-genome sequencing as Proteus mirabilis yielded a negative result. ConclusionsThe hilA gene represents a highly conserved and reliable molecular target for the detection of Salmonella spp. The developed TaqMan real-time PCR assay demonstrated high analytical sensitivity, excellent specificity, and broad serovar coverage, supporting its application in laboratory detection of Salmonella, food safety monitoring, and epidemiological surveillance.

Malaria remains a severe health problem in endemic regions because people lack adequate diagnostic tools, leading to delayed medical care and elevated death rates. This research introduces a dual-mode artificial intelligence system that uses two complementary models to enhance malaria pre-screening and diagnosis. The patient-centered model uses multivariate logistic regression to analyze biosignals, including heart rate, body temperature, and oxygen saturation, collected through a wearable sensor prototype and a mobile interface for symptom analysis. The system enables patients to begin self-assessment to determine their level of need before scheduling a doctor's appointment. The clinician-centered model represents a customized convolutional neural network that uses annotated microscopy images of red blood cells to achieve 94.84% accuracy, 95.71% precision, 93.87% recall, 94.78% F1 score, and 0.84 Area Under Curve (AUC). The patient model achieved 94.6% accuracy and an AUC of 0.985 using a 70/30 train-test split. These systems work together to create a layered diagnostic system that can operate independently or together to detect malaria at an early stage, especially in areas with limited resources. The findings demonstrate that wearable biosignal data integration with image-based deep learning can produce dependable, scalable, and user-friendly systems for malaria pre-screening. Keywords - malaria diagnosis, artificial intelligence (AI), convolutional neural networks (CNN), wearable biosensors, multivariate logistic regression

IntroductionLomentospora prolificans is a pathogenic filamentous fungus that causes disease primarily in people with severely compromised immune systems. It is pan-resistant to antifungal drugs, but the mechanism of its resistance to amphotericin B (AMB) is unknown. ObjectivesWe aimed to investigate the mechanism of resistance to AMB of L. prolificans. MethodsThe AMB susceptibility of L. prolificans protoplasts was measured using broth microdilution. L. prolificans, either intact, homogenized or fractionated was incubated with AMB in broth. The same activity was carried out with Aspergillus fumigatus as a control. This broth was then used to prepare microdilution plates with Saccharomyces cerevisiae to determine the activity of the conditioned AMB. ResultsAMB was 16-fold more effective in inhibiting the growth of L. prolificans protoplasts than conidia, but only two-fold more effective against A. fumigatus protoplasts than conidia. Incubation of L. prolificans hyphae with AMB in media diminished drug activity to a much greater extent than A. fumigatus, with 8-fold greater fungal mass of the latter required to achieve the effect of the former. Homogenization and fractionization of L. prolificans revealed that the factor inhibiting AMB activity was soluble with a mass >100 kda. DNase, trypsin, proteinase K, amyloglucosidase, SDS and 0.22 m had no effect on the AMB resistance factor, while treatment with urea, acetonitrile inactivated it. ConclusionWe report a different mechanism for AMB resistance based on the existence of a substance residing in the L. prolificans cell wall that can eliminate the antifungal activity of AMB.

Melanins are biological macromolecule with immense functionality synthesised by a wide spectrum of living organism. It is mainly synthesised by the oxidative polymerization of indolic and phenolic compounds through several enzymatic process. It has wide spread application in agriculture, cosmetic and therapeutic industry due to its various properties including antioxidation ability, UV protection efficiency and anticancer activity. Because of this wide range of application in different sectors, large scale production and commercialization attains enormous consideration. The present study deals with the effect of 12 different process parameters on melanin production viz., production media, incubation time, inoculum concentration, pH, temperature, agitation, carbon source, phosphate and magnesium source, CuSO4.5H2O, sodium chloride and L-tyrosine on melanin production by Pseudomonas stutzeri strain BTCZ 109 obtained from Arabian sea sediments was evaluated. After optimizing the important process parameters, the bacteria showed about ~4.65 fold increase in melanin production compared to unoptimized cultural conditions. The melanin optimized through this method was found to be nano sized. The Nano sized DOPA melanin in treating Skin cancer cell line SK ML28 which showed a dose-dependent activity with an IC50 value of 164 g/mL. All these results highlight the therapeutic efficiency of DOPA melanin Nano particle as promising bioactive molecule.

Background: Human activities such as mining generally lead to increased heavy metal concentrations in the environment. While traditional remediation techniques are often costly, the use of fungi as bioremediators, known as mycoremediation, is increasingly gaining attention as a sustainable approach for removal of heavy metals. Here, we evaluated heavy metal levels inside the Kiirunavaara iron ore mine in Northern Sweden and analysed fungal responses to various metal concentrations by comparing growth and metal uptake in mine-derived isolates and closely related control isolates. Results: Sediments inside the mine were enriched in heavy metals compared to those from the outlet of the mine to natural lakes. Six Fusarium isolates were recovered from contaminated mining environments: five isolates from inside the mine were identified as Fusarium oxysporum, and one isolate from the outlet was identified as Fusarium tricinctum. Isolates from the mine and outlet showed overall higher survival and biomass production in presence of copper, iron, and zinc across a range of concentrations (up to 1000 mg/L) compared to control isolates. At the same time, these isolates often exhibited reduced relative metal uptake. As a result, mycoremediation potential, assessed as total uptake in the grown mycelium, was isolate-dependent. Conclusions: Based on these results, we conclude that Fusarium isolates from the Kiirunavaara mine show increased growth in media enriched with heavy metals compared to closely related control isolates. We additionally show that mycoremediation potential is not necessarily associated with environmental origin. Instead, mycoremediation potential should be evaluated on a case-by-case basis for each isolate and based on specific needs for mycoremediation.

Fasciola hepatica is a trematode parasite responsible for fasciolosis, a liver disease that affects humans and livestock worldwide. Together with other food-borne trematode infections, fasciolosis is considered a neglected tropical disease. Further, it imposes substantial agricultural losses due to infections in ruminants. No vaccine is currently available, and control heavily relies on drug treatment, especially with triclabendazole (TCBZ). However, the intensive use of TCBZ over the past four decades has led to increasing rates of treatment failures and the emergence of drug-resistant parasites. Therefore, the identification of new treatment options is an urgent priority. The currently available toolset for drug screening, however, is limited. To address this need, we established a novel, semi-automated, standardized, and objective screening assay based on motility monitoring of newly excysted juveniles using microscopic live imaging. The assay was validated by testing a panel of ten compounds with known anthelmintic properties, amongst them TCBZ (IC50: 1.5 {micro}M) and the new activator of the F. hepatica transient receptor potential melastatin (TRPM) ion channel, benzamidoquinazolinone (IC50: 1.05 {micro}M). In addition to these two compounds with known activity against F. hepatica, three compounds were identified as particularly promising with a fast onset of action and IC50 values in the nanomolar range: the salicylanilides MMV665807 (IC50: 44 nM), niclosamide (IC50: 32 nM), and its ethanolamine salt, niclosamide ethanolamine (IC50: 9 nM). Complementary live/dead staining revealed that only TCBZ displayed parasiticidal activity, while the other compounds, although leading to parasite paralysis, did not lead to parasite death within 72 hours. Scanning electron microscopy of drug treated parasites did not reveal any significant damage at concentrations corresponding to the IC50s, but strong phenotypes were visible at 20 {micro}M. The presented motility assay provides a robust method for the discovery of novel anthelmintic compounds and facilitates the ongoing effort to combat fasciolosis. Author SummaryFasciola hepatica, the common liver fluke, is a parasitic platyhelminth that infects the liver and biliary ducts of humans and livestock, causing fasciolosis, a Neglected Tropical Disease as defined by the World Health Organization. Triclabendazole is the drug of choice to treat humans and animals. However, its intensive use has led to the emergence of drug resistance resulting in treatment failures worldwide. The identification of novel drugs is therefore urgent. Here, we present a semi-automated and objective method to assess the activity of compounds on one of the key life stages of the parasite: the newly excysted juveniles (NEJ). This stage is highly motile and motility assessment can be exploited to screen for bioactive compounds. Using time-lapse imaging, we quantified NEJ movement after drug exposure. From a panel of ten tested reference anthelmintics, two known fasciolicides (triclabendazole and benzamidoquinazolinone) and three additional compounds (MMV665807, niclosamide, and niclosamide ethanolamine) displayed particularly strong activity and were selected for further investigation. This method represents a robust tool for drug screening and facilitates the discovery of new compounds against F. hepatica.

Germicidal UV devices offer a promising solution to mitigate surface-mediated pathogen transmission, providing effective disinfection without material corrosion. This study evaluated the surface inactivation kinetics of two bacteria and two bacteriophages using a low-pressure (LP) mercury UV lamp (254 nm) and a filtered krypton chloride (KrCl*) excimer lamp (222 nm). Three deposition methods (Spray, Spread, and Pipette) and two extraction methods (Swab and Elute) were compared. The UV dose response on surfaces followed a two-region non-linear model due to shielding from dried deposition constituents, primarily through UV absorption. KrCl* excimer exhibited similar bacterial inactivation but slightly lower viral inactivation than LP UV lamp (maximum inactivation [~] 1 log lower), but its safety profile makes it compelling in occupied spaces. Compared to aqueous conditions, bacteria were more UV sensitive on surfaces, whereas viruses were more resistant. The deposition methods affected the inactivation results, with the Spray method resulting in higher bacteria inactivation. While the extraction methods had limited effect on inactivation efficacy, the Swab method provided higher inactivation detection limits ([~] 2 log higher) and more consistent extraction efficiency. This study provides mechanistic insights into the effects of deposition conditions, UV wavelengths, and microbial characteristics on UV surface disinfection and contributes to standardization of testing methods. TOC Graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/734141v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@11db511org.highwire.dtl.DTLVardef@15aa3faorg.highwire.dtl.DTLVardef@1c39ac9org.highwire.dtl.DTLVardef@e726ed_HPS_FORMAT_FIGEXP M_FIG C_FIG

Culture conditions were optimized for the production of melanin nanoparticle by the bacterial strain Pseudomonas stutzeri BTCZ 305. Response surface methodology was employed for determining the most significant fermentation conditions using variables including, pH, temperature and L-tyrosine concentration identified through one-factor-at-a time approach. Box-behnken design consisting of 17 different combinations of all these factors were performed. Using this methodology, a quadratic regression model was built and the optimal combinations of media constituents for maximum melanin production 1192.27 microg/mL were determined as temperature (32.5 degreeC), pH (8.5) and L-tyrosine concentration (7 g/L). Melanin production was obtained experimentally coincident with the predicted value and the model was proven to be adequate. The nanostructural distribution, its stability in colloidal suspension and particle size were also characterized with the help of TEM, particle size analysis and Zeta potential. The potent applicability of this molecule in anti-inflammation and wound healing was also elucidated.

Introduction: Rapid pathogen identification, resistance detection, and susceptibility profiling improve antimicrobial prescribing and associated outcomes, but fragmented workflows lead to inefficiencies and are costly. We evaluated a research-use-only (RUO) approach using ASTar(R) remnant bacterial suspension from routine AST for MALDI-TOF MS pathogen identification and Lateral Flow Assay (LFA)-based detection of targeted resistance mechanisms. Methods: Gram-negative (GN) bacterial strains from reference and curated resistance collections (CDC1, ARLG2, ATCC3) [n=119] were contrived into blood culture bottles and processed in the ASTar 16 System using the ASTar BC G- Kit (Q-linea AB, Sweden). Under RUO conditions, remnant bacterial suspensions were collected ~1-2 h after ASTar run initiation and analyzed using NG Test CTX-M Multi, NG Test CARBA-5, NG Test Acineto-5 RUO, and MALDI-TOF MS. Results: Mean ({+/-} SD) remnant suspension volume was 2722 L ({+/-} 300 L). All samples yielded high confidence MALDI-TOF MS scores (>2.0), with five initially scoring <2.0 and resolving on repeat testing. LFA results showed full agreement with reference isolates for blaCTX-M positive/negative (30/30) and with 60 or 61 target carbapenemase-positive/negative isolates. Testing of a subset of samples to mimic reflex workflows with ASTar phenotypic results did not affect LFA performance 24 (n=26; 23 Enterobacterales, 3 P. aeruginosa and 9 A. baumannii). Cost savings can be realised versus commercial multiplex PCR. Conclusion: This integrated approach of ~6 h rapid phenotypic AST with same-run identification and resistance detection (1-2 h from instrument start) or reflex testing upon availability of ASTar results may support earlier susceptibility results and offer cost savings to current workflows.

Aminopeptidases are widely distributed in bacteria, but outside of a few model strains, their function is largely unexplored. Focussing on beta-alanine aminopeptidase activity, a new series of selectively-activatable, caged fluorescent probes were designed and synthesised. A beta alanine amino acid was coupled to resorufin or 7-hydroxycoumarin via a self-imolative linker, such that amino acid removal led to gain of fluorescence. These were used to probe selectivity and specificity of probe activation, against a range of priority drug-resistant pathogens. When added to bacterial growth curves run in Muller Hinton broth, these probes allowed essentially real time fluorescence measurement of activation by bacterial species, modelled on the standard microbroth dilution method. Activation was observed for all Pseudomonas aeruginosa and Burkholderia spp strains tested. Selective activation was seen for Ochrabactrum species, with the probe activated by O.anthropii (2/4 strains) but not O.intermedium and strain-specific activation was seen for some isolates of Serratia marcescens (2/4 strains). No activation was observed in any isolates of Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii or Staphylococcus aureus or Eneterocccus faecium/faecalis PAO1 transposon mutants in the putative beta-alanine aminopeptidase gene (annotated as bapF or dmpA; PW3678) showed no activation of the probe in growth assays, confirming the specificity of the probe for beta-alanine aminopeptidase. Transposon mutants in other aminopeptidase genes, including those encoded by pepN, PepP and the prolyl aminopeptidase gene had no effect on probe activation in PAO1. Based on the operon structure in PA01, transposon mutants in two adjacent genes were also tested for probe activation. Mutants in both a putative transcriptional regulator (PW3674) and a predicted amino acid permease (PW3676) retained their ability to activate the beta-alanine probes with activation significantly higher than the wild type, when assessed by the total fluorescence yield after 10 hours growth. This points to both redundancy in permease function and perhaps the presence of a feedback regulatory mechanism controlling beta alanine aminopeptidase activity in P.aeruginosa. Given that the operon structure is conserved in other species, this may point to a common mechanism of beta alanine aminopeptidase function, perhaps related to exploiting beta-alanine containing peptides in certain environmental niches.

Background: Phenotypic antibiotic susceptibility testing (AST) for Helicobacter pylori (H. pylori) has relied on bacterial culture for three decades, requiring 5-7 days to yield results. Genotypic rapid tests can only detect known resistance mutations and fail to reliably identify amoxicillin resistance. To our knowledge, no culture-free rapid phenotypic AST method for H. pylori has been previously reported. Methods: We developed a phenotypic AST method based on fluorescence rapid on-site evaluation (ROSE) technology that completely bypasses bacterial culture. Gastric mucosal biopsy specimens from 40 H. pylori-positive patients were homogenized and co-incubated with an acridine orange/ethidium bromide (AO/EB)-based viability staining reagent and three first-line antibiotics (amoxicillin, clarithromycin, and levofloxacin) at concentrations corresponding to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints for H. pylori, at 37C for 1 hour. Fluorescence intensity was measured using a microplate reader. A reduction in fluorescence relative to an antibiotic-free control indicated susceptibility, whereas no significant reduction indicated resistance. Conventional culture-based AST (E-test) served as the reference method. The overall concordance rate, sensitivity, specificity, and Cohen's kappa coefficient were calculated. Results: Fourteen of the 40 samples had unsuccessful culture and were excluded, leaving 26 samples for statistical analysis of each antibiotic. The overall concordance rates between the ROSE method and culture-based AST were 84.6% (22/26) for amoxicillin, 76.9% (20/26) for levofloxacin, and 69.2% (18/26) for clarithromycin. Cohen's kappa coefficients indicated moderate agreement for all three antibiotics ({kappa} = 0.523, 0.539, and 0.412, respectively). Unlike genotypic methods, the ROSE method successfully assessed amoxicillin susceptibility in all 40 patients, a critical first-line antibiotic for which no reliable genetic resistance marker currently exists. The turnaround time was approximately 1 hour (55-65 minutes), compared with 5-7 days for culture-based methods; preliminary estimates indicated a cost reduction of approximately 3,000-5,000 Chinese yuan (CNY) per patient, mainly attributable to the elimination of culture media, prolonged incubation, and repeat clinic visits. Conclusions: This study reports, for the first time, a culture-free 1-hour phenotypic AST for H. pylori. The method enables same-day, susceptibility-guided treatment decisions, addressing an unmet clinical need spanning three decades. Algorithm optimization and a prospective randomized controlled trial are currently underway to further improve diagnostic accuracy and validate clinical utility.

The COVID-19 pandemic has imposed a reevaluation of safety protocols across various sectors, including the arts. This study addresses a critical gap in understanding SARS-CoV-2 persistence on materials commonly associated with musical instruments and scores, such as alloys, varnishes, reeds, and paper. While previous research has explored viral survival on various surfaces, limited data exists for materials specific to musical contexts. In this work, we investigate the efficacy of quarantine as a non-destructive method for inactivating SARS-CoV-2 on 16 materials, including brass, silver plating, ABS plastic, ebonite, and various varnishes and paper types. Results revealed significant variability in viral persistence across materials. Non-porous surfaces like metals and ABS plastic cleared infectivity within 3 days, while porous materials such as reeds and music scores required up to 7 days. Gold-plated brass and certain varnishes showed intermediate persistence, with infectivity clearing after 4 days. These findings are in agreement with prior studies indicating that SARS-CoV-2 survival is highly dependent on surface composition, with porous and organic-coated materials retaining viable virus longer due to reduced environmental stress. Our results highlight the feasibility of stratified quarantine protocols based on material type, offering practical guidelines for musicians and institutions and provides critical insights for mitigating SARS-CoV-2 transmission risks in musical settings.

Manual intervention for concrete repair and replacement comes at high environmental and economic costs. Bioconcrete, which can be formed by bacteria via microbially-induced carbonate precipitation (MICP), is a sustainable method for concrete repair. Bioconcrete-forming bacteria can be incorporated into the concrete at mixing and then heal cracks where and when they occur. Bioconcrete is not intentionally made by bacteria; rather, it is a byproduct of alterations to the local environment that occur during their normal metabolic activities. Bacteria thus make bioconcrete by different metabolic mechanisms, and the environment plays a substantial role in the yield and physical properties of the bioconcrete produced by a given bacterium. The ureolytic bacterium Sporosarcina pasteurii is the most commonly used model organism for MICP, but it requires urea supplementation, which is not feasible for all applications because of nitrogenous waste. In particular, the marine environment is understudied for bioconcrete applications, yet there is a need for self-healing structures in this environment, wherein urea and nitrogenous waste would be detrimental to native biota. Here, we assessed the ability of S. pasteurii to form bioconcrete under marine-like media conditions with urea and calcium supplementation. We found that S. pasteurii generated higher bioconcrete yields in these media conditions compared to standard growth media. We then designed an enrichment protocol to isolate and characterize non-urea-requiring bioconcrete-forming bacteria from Atlantic seawater. We identified three isolates, from the Sulflitobacter, Marinobacter, and Bacillus genera, two of which yielded higher bioconcrete yields in seawater-mimicking media compared to non-ureolytic bacteria utilized in prior literature. Moreover, scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy revealed distinct chemical and structural features of the bioconcrete produced by bacteria in seawater-mimicking medium and between ureolytic and non-ureolytic cultures. Overall, our work establishes a pipeline for the isolation and characterization of novel bioconcrete-forming bacteria from marine samples, with potential for application to marine self-healing materials.

Oligella otitidis MSHR-50489EDL strain (ATCC: TSD462; DSMZ: DSM118617) is a new species of the genus Oligella that was isolated from a middle ear discharge swab from a child with chronic suppurative otitis media (CSOM). This Gram-negative coccobacillus produces small, circular, smooth, whitish-opaque and occasionally mucoid colonies. It grows in aerobic conditions at a temperature range from 25-42oC. Phylogenetic analysis demonstrates a relationship to other species of the genera Oligella and average nucleotide identity and digital DNA/DNA hybridization values indicate a distinct species in comparison to other Oligella species. Thus far, the majority of isolates exhibit resistance to ciprofloxacin, the first line treatment for CSOM.

With the rapid expansion of global food demand, aquaculture has become a critical pillar for future food security. However, aquaculture systems remain highly vulnerable to pathogenic bacteria, and rapid identification of antagonistic microbes is essential for sustainable disease control. Conventional evaluation approaches rely on fluorescence labeling or post-culture assays, limiting the ability to quantify dynamic interactions in mixed microbial populations in a real-time and label-free manner. Here, we propose a computational framework for classifying the mixing ratio of Vibrio harveyi and environmental bacteria using time-series motion features extracted from microscopy videos. We defined 24 interpretable motility descriptors and employed a Temporal Convolutional Network (TCN) to learn their temporal structure. The proposed method achieved a classification accuracy of 93.3%, outperforming conventional static statistical approaches and alternative machine learning models. These findings indicate that mixture discrimination in microbial communities is governed not by absolute motility magnitude, but by collective alignment and its temporal stability. Our study establishes a time-resolved computational framework for quantifying dynamic collective order in mixed microbial populations and highlights its potential for label-free automated screening and robotic microbiological applications.

Compact poultry raising has turned poultry litter into an environmental problem, as it may all be packed with heavy metals and drug-resistant germs. Of all the metals, chromium contamination not only disturbs the general environment but is also a source of concern for public health. Poultry litters were taken from 14 farms in different places, and the bacteria characters from different places were tested for their capacity to tolerate Cr(VI). A total of 31 bacterial isolates were initially screened, and three of them (AH-2, AZ-1, and AMF-3) appeared to be very resistant to chromium. The isolates were able to survive at the highest concentration, 800 mg/L of the Cr(VI); however, AH-2 was the most resistant one (MIC: 900 mg/L; MBC: 1000 mg/L). Chromium reduction tests showed that AMF-3 at high concentration showed the maximum chromium reduction, while AH-2 achieved higher chromium reduction at medium concentration. Phenotypic and biochemical analysis showed that the isolates were Staphylococcus spp., which was confirmed by 16S rRNA gene sequencing as S. cohnii, S. saprophyticus, and S. gallinarum. Moreover, chromium was detected at higher levels in poultry litter compared to the feed, with the highest accumulation in AZ farm litter (4464.0 {micro}g/kg). The highlighting feature of our article is the presence of chromium-tolerant and reducing bacteria in poultry environments. Besides that, the level of chromium in poultry litter is really high, and it points to the need for better waste management.

IntroductionEnteric fever, being endemic with seasonal peaks in low- and middle-income countries, is a major health concern. Moreover, the rise in antibiotic resistance has exacerbated the situation. This study was undertaken to investigate the lytic bacteriophages against Salmonella Typhi with a potential for phage therapy. Materials and MethodsA hospital-based cross-sectional study was conducted from October 2023 to March 2024. Blood cultures were processed by the BACTEC automated culture system following standard microbiological techniques to isolate typhoidal Salmonella. Antibiotic susceptibility was tested by the modified Kirby-Bauer disc diffusion method. Lytic bacteriophages isolated by the double-layer agar method were assessed for their host range and lytic ability with spot and turbidimetric assays. ResultsOf the total 1054 blood specimens, 35 (3.2%) were positive for S. Typhi. All the isolates were susceptible to first-line antibiotics--ampicillin, chloramphenicol, and cotrimoxazole. The isolates were also sensitive to nalidixic acid (80%) as well as fluoroquinolones; ciprofloxacin (62.86%), levofloxacin (77.14%), and ofloxacin (80%). Fifteen lytic phages were isolated against S. Typhi Ty2 and CT18 strains. Four phages--vB_SaTy_ST2, vB_SaTy_ST7, vB_SaTy_ST17, and vB_SaTy_ST18--lysed all 35 clinical S. Typhi isolates. While vB_SaTy_ST17 and vB_SaTy_ST18 also lysed 7 out of 20 S. Paratyphi A isolates. Three phages (vB_SaTy_ST2, vB_SaTy_ST7, vB_SaTy_ST17) were tested against S. Typhi isolate S30. Individually, vB_SaTy_ST17 suppressed the growth for 13 hours, vB_SaTy_ST2 and vB_SaTy_ST7 for 10 hours. The phage cocktail vB_SaTy_ST2 + vB_SaTy_ST17 was the most effective, which extended the inhibition time to 15 hours. ConclusionThis study highlights the ongoing burden of enteric fever in Nepal and the increase in susceptibility of S. Typhi to nalidixic acid and fluoroquinolones. It also demonstrates the promising lytic potential of bacteriophages, particularly vB_SaTy_ST17 and the phage cocktail vB_SaTy_ST2 + vB_SaTy_ST17, against clinical S. Typhi, highlighting their potential as alternatives to antibiotics.