Norberto Gonzalez-Juarbe

Background/Objectives: Serratia marcescens is an opportunistic pathogen that causes severe hospital-acquired infections, notable for its biofilm formation abilities and development of extensive antibiotic resistance. Here, we aim to evaluate the efficacy of bacteriophages, antibiotics, and antimicrobial peptides (BAP), alone and in combination, against fourteen multidrug-resistant (MDR) S. marcescens isolates sourced from hospitals and other environmental settings. Methods: S. marcescens was grown planktonically or in surface-associated biofilms, and biofilm biomass was measured via changes in absorbance and colony-forming units or live/death staining. Results: Combining bacteriophage with a low-dose cocktail of penicillin–streptomycin, kanamycin, and ciprofloxacin enhanced antimicrobial activity compared with antibiotics alone. Across the isolate panel, responses to BAP treatment varied according to determined antibiotic resistance profiles. The highly resistant AR-0517 isolate was selected for detailed mature biofilm analysis, where the BAP treatment reduced biofilm biomass by 97.8% and recoverable bacteria by 99.99%. Microscopy and viability assays further confirmed extensive biofilm disruption and bacterial killing. Conclusions: These findings demonstrate that simultaneous targeting of multiple bacterial pathways can enhance antimicrobial activity against MDR S. marcescens in vitro and support further evaluation of BAP as a potential strategy for biofilm-associated infections.

Communication between gut microbiota and extraintestinal organs is increasingly recognized, yet elucidation of relevant translocation mechanism(s) remains enigmatic. Vagus neuroanatomy and reports of vagal protein transfer to extraintestinal organs suggest that this “superhighway” could translocate bacteria. Here we explore whether the vagus superhighway can translocate bacteria to extraintestinal organs. Gavage of green fluorescent protein–expressing Escherichia coli (GFP- E. coli) into germ-free (GF) or specific-pathogen free (SPF) C57BL/6 mice yielded high bacillary loads in the stomach and lungs, followed by the heart, stool and peripheral muscles, despite negative blood cultures. Notably, confocal microscopy and culture revealed GFP- E. coli within the vagus nerve within five minutes of gavage suggesting rapid translocation. Metagenomic analysis of stool, lung, heart, vagus nerve, and muscle from non-gavaged SPF mice demonstrated significant microbial overlap, supporting that bacterial translocation occurs despite the presence of endogenous microflora. Remarkably, subdiaphragmatic vagotomy performed prior to GFP- E. coli gavage resulted in marked reductions of bacterial transduction in the lungs and other extraintestinal organs, except muscle. Furthermore, vagotomy significantly reduced lung fibrosis in SPF mice following intranasal bleomycin administration. In lung cancer patients undergoing lobectomy, vagotomy inhibited postsurgical reductions in forced vital capacity. These findings identify the vagus nerve as a literal gut–lung axis, facilitating viable bacterial translocation and influencing lung severity.

Serratia marcescens is an opportunistic pathogen that causes severe hospital-acquired infections, notable for its biofilm formation abilities and development of extensive antibiotic resistance. Here we evaluated the efficacy of bacteriophages, antibiotics, and antimicrobial peptides (BAP), alone and in combination, against fourteen multi-drug-resistant (MDR) S. marcescens isolates sourced from hospitals and other environmental settings in an in vitro biofilm model. Phage combination with a cocktail of sub-minimal inhibitory concentration (MIC) of penicillin-streptomycin, kanamycin, and ciprofloxacin, reduced biofilm biomass, however, complete decolonization was not achieved. Incorporating an antimicrobial peptide cocktail into this regimen eradicated 99.99% of multi-drug-resistant isolates grown planktonically or in surface-associated biofilms. Microscopy and viability assays confirmed extensive biofilm disruption and bacterial clearance without regrowth. These findings reveal that simultaneous interference of cell wall synthesis, protein translation, DNA replication, and membrane integrity can overcome S. marcescens antimicrobial defenses, establishing a multifaceted therapeutic framework for managing device-associated infections caused by MDR pathogens.

Cultural heritage objects can accumulate DNA from materials, environments, and repeated human contact, but biomolecular profiling of such items is constrained by nondestructive sampling requirements, ultra-low biomass, and high contamination risk. Here we present a minimally invasive workflow that integrates gentle swab collection, low-input whole-metagenome sequencing, taxonomic profiling, and Y-chromosome analyses to recover ″biological signatures of history″ from Renaissance-era artwork and archival correspondence associated with ancestors of Leonardo da Vinci. Across artifacts, we recovered heterogeneous mixtures of microbial and eukaryotic DNA (including bacteria, fungi, plants, and viruses) consistent with composite ″biomes″ that reflect differences in substrate, storage, conservation treatments, and handling. Multivariate comparisons show reproducible sample-to-sample separations. In parallel, we assessed human Y-chromosome signal using a panel of ~90,000 phylogenetically informative markers and partial Y-STR profiling where feasible. Across multiple independent swabs from Leonardo da Vinci-associated items, the obtained Y chromosome marker data suggested assignments withing the broader E1b1/E1b1b clade. However, the control samples also indicate mixed contributions consistent with modern handling and other sources. Together, these data demonstrate the feasibility as well as limitations of combining metagenomics and human DNA marker analysis for cultural heritage science, providing a baseline workflow for future conservation science studies and hypothesis-driven investigations of provenance, authentication and handling history.

Background/Objectives: Biofilm formation by Acinetobacter baumannii contributes to its persistence in clinical settings and resistance to antibiotic treatment. This study aims to identify and characterize antimicrobials from lactic acid bacteria (LAB) using molecular and in silico approaches that can prevent and disrupt A. baumannii biofilms, assess their antimicrobial host range, and define their synergy with current antibiotics. Methods: Thirteen LAB isolates from the Human Microbiome Project were screened for anti-biofilm activity against A. baumannii. Conditioned media was further tested against six ESKAPE pathogens and three skin commensals. Lentilactobacillus hilgardii was selected for detailed study and antimicrobial peptide (AMP) prediction analysis due to limited toxicity toward commensals. In silico identified peptides were synthesized and tested individually and in combination with sub-MIC doses of an antibiotic. Results: Conditioned media from five LAB species (Lentilactobacillus hilgardii, Lentilactobacillus buchneri, Ligilactobacillus ruminis, Limosilactobacillus fermentum, and Limosilactobacillus antri) significantly inhibited A. baumannii biofilm formation and reduced biomass of mature biofilms. LAB-conditioned media also exhibited broad-spectrum activity against ESKAPE pathogens, though effects on commensals varied. Bioinformatically predicted AMPs from L. hilgardii inhibited planktonic A. baumannii growth but showed no direct biofilm activity even at high doses. However, AMPs were found to synergize with sub-MIC doses of meropenem against mature biofilms leading to decolonization. Conclusions: Our study provides a comprehensive platform for the discovery and characterization of AMPs and supports using commensal bacteria to reduce, prevent, and decolonize biofilms from pathogenic bacteria in community and nosocomial settings.

Streptococcus pneumoniae is responsible for causing a range of diseases, from self-limiting otitis media to more severe disease such as pneumonia, sepsis, and meningitis. Vaccines and antibiotics have successfully decreased this disease burden; however, serotype replacement due to vaccines and antibiotic resistance remain issues pointing to the need for further research into alternative methods of treatment. S. pneumoniae continues to pose a global threat to young children and the elderly. Endolysins, which function as peptidoglycan hydrolases, are an attractive alternative treatment given their rapid bactericidal activity, specificity, and lack of noted resistance. This review considers the uses of endolysins within the main niches of infection for S. pneumoniae: pulmonary, middle ear, and the bloodstream and central nervous system. Therapeutic hurdles, such as delivery and mechanical barrier challenges, are discussed and endolysin-focused solutions to circumvent these challenges are proposed. The ability to address niche-specific hurdles using endolysins will allow for an increase in effective therapies against S. pneumoniae.

Withdrawal Statement: The authors have withdrawn this manuscript because upon peer review major revisions have been identified as needed to ensure that the conclusions are in par with the presented data. Current studies are ongoing to provide a more complete version of the manuscript for peer review publication. Therefore, the authors do not wish this work to be cited as reference for the project in its current form. If you have any questions, please contact the corresponding author.

This study investigates the efficacy of conditioned media derived from lactic acid bacteria (LAB) in preventing and disrupting Acinetobacter baumannii biofilms. Of the 13 LAB isolates from the Human Microbiome Project tested, five distinct species Lentilactobacillus hilgardii, Lentilactobacillus buchneri, Ligilactobacillus ruminis, Limosilactobacillus fermentum, and Limosilactobacillus antri demonstrated significant prevention of A. baumannii biofilm formation and reduced the biomass of pre-formed mature biofilms. The study extended to the six ESKAPE pathogens and three skin commensals, demonstrating broad-spectrum antimicrobial activity of LAB conditioned media against ESKAPE pathogens, albeit with variable effects on skin commensals. L. hilgardii was characterized further due to its reduced toxicity against skin commensals. Fractionation studies indicated potential peptide involvement; thus, bioinformatic analysis was used to predict antimicrobial peptides (AMPs) within the L. hilgardii genome, which were synthesized and tested, showing effective inhibition of A. baumannii planktonic growth. However, these peptides did not affect biofilms at concentrations up to 30 µg/mL, although synergy with sub-MIC levels of meropenem significantly disrupted mature biofilms. Our study provides a comprehensive platform for the discovery and characterization of AMPs and support the notion of how commensals can be used to reduce, prevent and decolonize biofilms from pathogenic bacteria in community and nosocomial settings.