Acinetobacter baumannii is a critical threat to immunocompromised patients, particularly those with burn injuries. Despite its clinical significance, little is known about how this bacterium adapts to the complex environment of burn patient blood, which differs significantly from that of healthy individuals. To address this, our methods included analyses of a blood-isolated strain of A. baumannii A118 grown ex vivo in whole blood from healthy volunteers (WBHV) and burn patients (WBBP). Transcriptomic analysis revealed host-specific expression patterns, including the downregulation of acinetobactin siderophore genes in WBBP—suggesting increased free iron levels—and the strong upregulation of nitrate/nitrite metabolism genes, indicating altered nitrogen availability in burn patients’ blood. Since serum makes up the majority of blood volume and contains key factors influencing bacterial physiology, we examined the transcriptomic response of A. baumannii to pooled human serum in an LB + 10% serum model at two different time points of growth, isolating the impact of soluble components free from immune cells and building on patterns seen in whole blood. Consistent with our ex vivo findings, we again observed dynamic regulation of the acinetobactin operon—this time in response to serum exposure: an initial upregulation of key iron uptake genes at early time points was followed by strong downregulation later, suggesting a transient iron starvation response that is modulated as intracellular iron accumulates, which can be supported by our ICP-MS results, revealing increased intracellular iron and other metal ions in serum-treated bacteria over time. To support additional serum-induced transcriptomic findings beyond acinetobactin, we used multiple experimental approaches: LC–MS/MS of outer membrane protein (OMP) extracts identified a serum-upregulated acinetobactin transporter; and phenotypic assays revealed that serum enhanced biofilm formation, increased twitching motility, elevated mortality in the Galleria mellonella infection model, and raised minimum inhibitory concentration (MIC) for multiple antibiotics. In conclusion, these findings expand our understanding of pathogen behavior in clinically relevant conditions and suggest that host-specific blood physiology—especially in burn patients—can shape the course of infection.

Acinetobacter baumannii is a major cause of bloodstream infections, yet its adaptation and survival mechanisms in human blood remain poorly understood. While previous studies focused on individual blood components, the impact of human whole blood on A. baumannii gene expression has not been explored. To address this, we used an ex vivo model where A. baumannii was grown in human whole blood from healthy volunteers (WBHV) and compared its gene expression to that in Luria-Bertani (LB) broth using RNA-seq. Our lab has previously employed a similar WBHV vs. LB comparison in Pseudomonas aeruginosa, validating this approach. Our results showed that ribosome biogenesis was the most upregulated pathway in WBHV, with 51 out of 55 ribosomal protein genes exhibiting increased expression. We then examined virulence related genes and found upregulation in iron and zinc acquisition systems (acinetobactin, znuABC) and biofilm/quorum sensing regulators, including the csu operon. Given these findings, we hypothesized that WBHV exposure enhances virulence. Using the Galleria mellonella infection model, we confirmed that A. baumannii caused higher larval mortality when grown in WBHV than when grown in LB. Upregulation of the csu operon, involved in pili assembly, led us to investigate twitching motility, where we observed a significant increase in WBHV. Additionally, since A. baumannii exhibits high drug resistance through the regulation of various outer membrane proteins (OMPs), we analyzed OMP expression in response to WBHV. SDS-PAGE and LC-MS/MS analysis identified three OMPs-Omp33-36, CarO, and OmpA-that were downregulated in WBHV. As these proteins mediate carbapenem uptake, we tested imipenem resistance using a minimum bactericidal concentration (MBC) assay and found that WBHV exposure increased A. baumannii's MBC to imipenem, suggesting reduced susceptibility. Our findings provide valuable insights into the adaptive mechanisms of A. baumannii in human whole blood, highlighting potential targets for combating its persistence and antibiotic resistance in bloodstream infections.

Emerging evidence shows that the gut microbiota plays an important role in neuropathic pain (NP) via the gut–brain axis. Male rats were divided into sham, spinal nerve ligation (SNL), SNL + 200 mg GEG/kg BW (GEG200), and SNL + 600 mg GEG/kg BW (GEG600) for 5 weeks. The dosages of 200 and 600 mg GEG/kg BW for rats correspond to 45 g and 135 g raw ginger for human daily consumption, respectively. Both GEG groups mitigated SNL-induced NP behavior. GEG-supplemented animals had a decreased abundance of Rikenella, Muribaculaceae, Clostridia UCG-014, Mucispirillum schaedleri, RF39, Acetatifactor, and Clostridia UCG-009, while they had an increased abundance of Flavonifactor, Hungatella, Anaerofustis stercorihominis, and Clostridium innocuum group. Relative to sham rats, Fos and Gadd45g genes were upregulated, while Igf1, Ccl2, Hadc2, Rtn4rl1, Nfkb2, Gpr84, Pik3cg, and Abcc8 genes were downregulated in SNL rats. Compared to the SNL group, the GEG200 group and GEG600 group had increases/decreases in 16 (10/6) genes and 11 (1/10) genes, respectively. GEG downregulated Fos and Gadd45g genes and upregulated Hdac2 genes in the amygdala. In summary, GEG alleviates NP by modulating the gut microbiome and reversing a molecular neuroimmune signature.

Multidrug-resistant bacteria present a significant public health challenge; such pathogens exhibit reduced susceptibility to conventional antibiotics, limiting current treatment options. Cationic non-ribosomal peptides (CNRPs) such as brevicidine and polymyxins have emerged as promising candidates to block Gram-negative bacteria. To investigate the capability of bacteria to biosynthesize CNRPs, and specifically polymyxins, over 11,000 bacterial genomes were mined in silico. Paenibacillus polymyxa was identified as having a robust biosynthetic capacity, based on multiple polymyxin gene clusters. P. polymyxa biosynthetic competence was confirmed by metabolite characterization via HPLC purification and MALDI TOF/TOF analysis. When grown in a selected medium, the metabolite yield was 4 mg/L with a 20-fold specific activity increase. Polymyxin B (PMB) was assayed with select nosocomial pathogens, including Pseudomonas aeruginosa, Klebsiella pneumonia, and Acinetobacter baumaii, which exhibited minimum inhibitory concentrations of 4, 1, and 1 µg/mL, respectively.

AbstractVersatility in carbon source utilization assistsPseudomonas aeruginosain its adaptation to various niches. Recently, we characterized the role of malonate, an understudied carbon source, in quorum sensing regulation, antibiotic resistance, and virulence factor production inP. aeruginosa. These results indicate that global responses to malonate metabolism remain to be uncovered. We leveraged a publicly available metabolomic dataset on human airway and found malonate to be as abundant as glycerol, a common airway metabolite and carbon source forP. aeruginosa. Here, we explored and compared adaptations ofP. aeruginosaUCBPP-PA14 (PA14) in response to malonate or glycerol as a sole carbon source using transcriptomics and phenotypic assays. Malonate utilization activated glyoxylate and methylcitrate cycles and induced several stress responses, including oxidative, anaerobic, and metal stress responses associated with increases in intracellular aluminum and strontium. Some induced genes were required for optimal growth ofP. aeruginosain malonate. To assess the conservation of malonate-associated responses amongP. aeruginosastrains, we compared our findings in strain PA14 with other lab strains and cystic fibrosis isolates ofP. aeruginosa. Most strains grew on malonate as a sole carbon source as efficiently as or better than glycerol. While not all responses to malonate were conserved among strains, formation of biomineralized biofilm-like aggregates, increased tolerance to kanamycin, and increased susceptibility to norfloxacin were the most frequently observed phenotypes. Our findings reveal global remodeling ofP. aeruginosagene expression during its growth on malonate as a sole carbon source that is accompanied by several important phenotypic changes. These findings add to accumulating literature highlighting the role of different carbon sources in the physiology ofP. aeruginosaand its niche adaptation.ImportancePseudomonas aeruginosais a notorious pathogen that causes local and systemic infections in immunocompromised individuals. Different carbon sources can uniquely modulate metabolic and virulence pathways inP. aeruginosa, highlighting the importance of the environment that the pathogen occupies. In this work, we used a combination of transcriptomic analysis and phenotypic assays to determine how malonate utilization impactsP. aeruginosa,as recent evidence indicates this carbon source may be relevant to certain niches associated within the human host. We found that malonate utilization can induce global stress responses, alter metabolic circuits, and influence various phenotypes ofP. aeruginosathat could influence host colonization. Investigating the metabolism of malonate provides insight intoP. aeruginosaadaptations to specific niches where this substrate is abundant, and how it can be leveraged in the development of much-needed antimicrobial agents or identification of new therapeutic targets of this difficult-to-eradicate pathogen.

Versatility in carbon source utilization is a major contributor to niche adaptation in Pseudomonas aeruginosa. Malonate is among the abundant carbon sources in the lung airways, yet it is understudied. Recently, we characterized how malonate impacts quorum sensing regulation, antibiotic resistance, and virulence factor production in P. aeruginosa. Herein, we show that malonate as a carbon source supports more robust growth in comparison to glycerol in several cystic fibrosis isolates of P. aeruginosa. Furthermore, we show phenotypic responses to malonate were conserved among clinical strains, i.e., formation of biomineralized biofilm-like aggregates, increased tolerance to kanamycin, and increased susceptibility to norfloxacin. Moreover, we explored transcriptional adaptations of P. aeruginosa UCBPP-PA14 (PA14) in response to malonate versus glycerol as a sole carbon source using transcriptomics. Malonate utilization activated glyoxylate and methylcitrate cycles and induced several stress responses, including oxidative, anaerobic, and metal stress responses associated with increases in intracellular aluminum and strontium. We identified several genes that were required for optimal growth of P. aeruginosa in malonate. Our findings reveal important remodeling of P. aeruginosa gene expression during its growth on malonate as a sole carbon source that is accompanied by several important phenotypic changes. These findings add to the accumulating literature highlighting the role of different carbon sources in the physiology of P. aeruginosa and its niche adaptation.

Versatility in carbon source utilization assists Pseudomonas aeruginosa in its adaptation to various niches. Recently, we characterized the role of malonate, an understudied carbon source, in quorum sensing regulation, antibiotic resistance, and virulence factor production in P. aeruginosa . These results indicate that global responses to malonate metabolism remain to be uncovered. We leveraged a publicly available metabolomic dataset on human airway and found malonate to be as abundant as glycerol, a common airway metabolite and carbon source for P. aeruginosa . Here, we explored and compared adaptations of P. aeruginosa UCBPP-PA14 (PA14) in response to malonate or glycerol as a sole carbon source using transcriptomics and phenotypic assays. Malonate utilization activated glyoxylate and methylcitrate cycles and induced several stress responses, including oxidative, anaerobic, and metal stress responses associated with increases in intracellular aluminum and strontium. Some induced genes were required for optimal growth of P. aeruginosa in malonate. To assess the conservation of malonate-associated responses among P. aeruginosa strains, we compared our findings in strain PA14 with other lab strains and cystic fibrosis isolates of P. aeruginosa . Most strains grew on malonate as a sole carbon source as efficiently as or better than glycerol. While not all responses to malonate were conserved among strains, formation of biomineralized biofilm-like aggregates, increased tolerance to kanamycin, and increased susceptibility to norfloxacin were the most frequently observed phenotypes. Our findings reveal global remodeling of P. aeruginosa gene expression during its growth on malonate as a sole carbon source that is accompanied by several important phenotypic changes. These findings add to accumulating literature highlighting the role of different carbon sources in the physiology of P. aeruginosa and its niche adaptation. Importance Pseudomonas aeruginosa is a notorious pathogen that causes local and systemic infections in immunocompromised individuals. Different carbon sources can uniquely modulate metabolic and virulence pathways in P. aeruginosa , highlighting the importance of the environment that the pathogen occupies. In this work, we used a combination of transcriptomic analysis and phenotypic assays to determine how malonate utilization impacts P. aeruginosa, as recent evidence indicates this carbon source may be relevant to certain niches associated within the human host. We found that malonate utilization can induce global stress responses, alter metabolic circuits, and influence various phenotypes of P. aeruginosa that could influence host colonization. Investigating the metabolism of malonate provides insight into P. aeruginosa adaptations to specific niches where this substrate is abundant, and how it can be leveraged in the development of much-needed antimicrobial agents or identification of new therapeutic targets of this difficult-to-eradicate pathogen.

Chronic wound infections are of clinical concern as they often lead to high rates of mortality and morbidity. A point-of-care handheld bacterial fluorescence imaging has been designed to detect the auto-fluorescent characteristics of most clinically relevant species of bacteria. This device causes most species of bacteria to exhibit red fluorescence due to the production of exoproduct porphyrins. One of the most significant contributors to the pathogenicity of chronic wounds is the pathogen Pseudomonas aeruginosa, and interestingly, this organism exhibits an additional unique cyan fluorescence signature. There is an over 90% positive predictive value that, when a chronic wound exhibits cyan fluorescence with the bacterial fluorescence imaging device, the wound will harbor P. aeruginosa. This project seeks to understand what genetic factor(s) contribute to the cyan phenotype observed.

Within the vaginal ecosystem, lactobacilli and Gardnerella spp. likely interact and influence each other’s growth, yet the details of this interaction are not clearly defined. Using medium simulating vaginal fluid and a two-chamber co-culturing system to prevent cell-to-cell contact between the bacteria, we examined the possibility that Lactobacillus jensenii 62B (Lj 62B) and/or G. piotii (Gp) JCP8151B produce extracellular factors through which they influence each other’s viability. By 24 h post-inoculation (hpi) in the co-culture system and under conditions similar to the vaginal environment – pH 5.0, 37 °C, and 5% CO 2 , Lj 62B viability was not affected but Gp JCP8151B had been eliminated. Cell-free supernatant harvested from Lj 62B cultures (Lj-CFS) at 20 hpi, but not 16 hpi, also eliminated Gp JCP8151B growth. Neither lactic acid nor H 2 O 2 production by Lj 62B was responsible for this effect. The Lj-CFS did not affect viability of three species of lactobacilli or eight species of Gram-positive and Gram-negative uropathogens but eliminated viability of eight different strains of Gardnerella spp. Activity of the inhibitory factor within Lj-CFS was abolished by protease treatment and reduced by heat treatment suggesting it is most likely a bacteriocin-like protein; fractionation revealed that the factor has a molecular weight within the 10–30 kDa range. These results suggest that, in medium mimicking vaginal fluid and growth conditions similar to the vaginal environment, Lj 62B produces a potential bacteriocin-like inhibitory substance (Lj-BLIS) that clearly targets Gardnerella spp. strains. Once fully characterized, Lj-BLIS may be a potential treatment for Gardnerella- related BV that does not alter the vaginal microflora.

Recurrent pulmonary exacerbation due to infection and inflammation remain the major cause of mortality and morbidity in patients with cystic fibrosis (CF). Increased levels of BPI-ANCA have been linked to Pseudomonas colonization and pulmonary exacerbations in patients with CF. The majority of these studies were done in Europe, and it is unclear whether similar findings are true in CF patients who lives in United States. In our single center study of 47 patients with CF, the prevalence of BPI-ANCA was 19% at baseline and 15% at annual follow-up visit. Overall, there were no statistical differences noted in FEV1 and frequency of pulmonary exacerbations in CF patients who were positive for BPI-ANCA compared to those who were negative for BPI-ANCA. The role of BPI-ANCA in patients with CF still remains unclear.

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes high morbidity and mortality in cystic fibrosis (CF) and immunocompromised patients, including patients with ventilator-associated pneumonia (VAP), severely burned patients, and patients with surgical wounds. Due to the intrinsic and extrinsic antibiotic resistance mechanisms, the ability to produce several cell-associated and extracellular virulence factors, and the capacity to adapt to several environmental conditions, eradicating P. aeruginosa within infected patients is difficult. Pseudomonas aeruginosa is one of the six multi-drug-resistant pathogens (ESKAPE) considered by the World Health Organization (WHO) as an entire group for which the development of novel antibiotics is urgently needed. In the United States (US) and within the last several years, P. aeruginosa caused 27% of deaths and approximately USD 767 million annually in health-care costs. Several P. aeruginosa therapies, including new antimicrobial agents, derivatives of existing antibiotics, novel antimicrobial agents such as bacteriophages and their chelators, potential vaccines targeting specific virulence factors, and immunotherapies have been developed. Within the last 2-3 decades, the efficacy of these different treatments was tested in clinical and preclinical trials. Despite these trials, no P. aeruginosa treatment is currently approved or available. In this review, we examined several of these clinicals, specifically those designed to combat P. aeruginosa infections in CF patients, patients with P. aeruginosa VAP, and P. aeruginosa-infected burn patients.

Abstract Background Glycogen metabolism by Lactobacillus spp. that dominate the healthy vaginal microbiome contributes to a low vaginal pH (3.5–4.5). During bacterial vaginosis (BV), strict and facultative anaerobes including Gardnerella vaginalis become predominant, leading to an increase in the vaginal pH (> 4.5). BV enhances the risk of obstetrical complications, acquisition of sexually transmitted infections, and cervical cancer. Factors critical for the maintenance of the healthy vaginal microbiome or the transition to the BV microbiome are not well defined. Vaginal pH may affect glycogen metabolism by the vaginal microflora, thus influencing the shift in the vaginal microbiome. Results The medium simulating vaginal fluid (MSVF) supported growth of L. jensenii 62G, L. gasseri 63 AM, and L. crispatus JV-V01, and G. vaginalis JCP8151A at specific initial pH conditions for 30 d. L. jensenii at all three starting pH levels (pH 4.0, 4.5, and 5.0), G. vaginalis at pH 4.5 and 5.0, and L. gasseri at pH 5.0 exhibited the long-term stationary phase when grown in MSVF. L. gasseri at pH 4.5 and L. crispatus at pH 5.0 displayed an extended lag phase over 30 d suggesting inefficient glycogen metabolism. Glycogen was essential for the growth of L. jensenii, L. crispatus, and G. vaginalis; only L. gasseri was able to survive in MSVF without glycogen, and only at pH 5.0, where it used glucose. All four species were able to survive for 15 d in MSVF with half the glycogen content but only at specific starting pH levels – pH 4.5 and 5.0 for L. jensenii, L. gasseri, and G. vaginalis and pH 5.0 for L. crispatus. Conclusions These results suggest that variations in the vaginal pH critically influence the colonization of the vaginal tract by lactobacilli and G. vaginalis JCP8151A by affecting their ability to metabolize glycogen. Further, we found that L. jensenii 62G is capable of glycogen metabolism over a broader pH range (4.0–5.0) while L. crispatus JV-V01 glycogen utilization is pH sensitive (only functional at pH 5.0). Finally, our results showed that G. vaginalis JCP8151A can colonize the vaginal tract for an extended period as long as the pH remains at 4.5 or above.

Background: Pseudomonas aeruginosa is an opportunistic, gram-negative pathogen and a major determinant of declining lung function in individuals with CF.It has many intrinsic antibiotic resistance mechanisms, and the alarming rate at which antibiotic-resistant mutants emerge necessitates the search for alternative therapies to treat P. aeruginosa infections.One such therapy is the use of R-pyocins, narrow-spectrum phage-like antimicrobials produced by P. aeruginosa to eliminate competitive P. aeruginosa.R-pyocins can be grouped into three subtypes (R1, R2, R5) that differ based on their binding to defined sites on the P. aeruginosa lipopolysaccharide (LPS) structure.We hypothesized that a purified, recombinant R-pyocin could kill P. aeruginosa in CF-relevant growth media in vitro and act as an antimicrobial by reducing the bacterial load during P. aeruginosa lung infection.Methods: We evaluated recombinant R-pyocin efficacy in vitro in CFrelevant growth conditions by testing a panel of P. aeruginosa strains routinely used in serotyping for susceptibility when grown in synthetic cystic fibrosis media (SCFM).In this assay, we grew P. aeruginosa strains in liquid SCFM cultures overnight, before inoculating soft agar to overlay SCFM agar (1.5%).Pyocins were spotted onto overlays in 5-μL drops of 0.6 mg/mL before overlay plates were incubated overnight at 37°C.We then tested recombinant R-pyocin efficacy in vivo using a murine acute pneumonia model.For the acute pneumonia model, 8-week-old female BALB/c mice were infected intranasally with a sublethal dose of P. aeruginosa per mouse in a 20-μL volume (10 μL per nostril); recombinant R-pyocin was delivered intranasally in a 20-μL volume (1.3 mg/mL) 15 minutes, 6 hours, or 12 hours after infection.Mice were euthanized 24 hours after infection to determine the level of bacterial burden in the lungs.Results: In our in vitro assays, many P. aeruginosa strains tested were susceptible to the recombinant R-pyocin in SCFM and exhibited differences in LPS from standard lab media lysogeny broth.In our in vivo acute pneumonia model, even mice receiving the delayed treatment showed a 2log decrease in CFUs/g burden in their lungs compared to untreated mice, indicating a significant reduction in infection.Conclusions: These results suggest that R-pyocins should be considered as an alternative to, or perhaps in combination with, antibiotics in the treatment of P. aeruginosa infections and show promise as antimicrobials under conditions similar to the CF lung.

Natural bioactive compounds are proposed as alternatives in mitigating obesity-associated skeletal muscle dysfunction. The objective of this study was to test the hypothesis that the combination of geranylgeraniol (GGOH) and green tea polyphenols (GTPs) can alleviate high-fat-diet (HFD)-induced muscle atrophy and alter gut microbiome composition. Male C57BL/6J mice fed an HFD were assigned to four groups (12 mice each) in a 2 (no GGOH vs. 400 mg GGOH/kg diet) × 2 (no GTPs vs. 0.5% weight/volume GTPs in water) factorial design. After 14 weeks of diet intervention, skeletal muscle and cecal samples were collected and examined. Compared to the control groups, the group that consumed a combination of GGOH and GTPs (GG + GTPs) had significantly decreased body and fat mass but increased skeletal muscle mass normalized by body weight and cross-sectional area. In soleus muscle, the GG + GTP diet increased citrate synthase activity but decreased lipid peroxidation. Gut microbiome beta-diversity analysis revealed a significant difference in the microbiome composition between diet groups. At the species level, the GG + GTP diet decreased the relative abundance of Dorea longicatena, Sporobacter termitidis, and Clostridium methylpentosum, and increased that of Akkermansia muciniphila and Subdoligranulum variabile. These results suggest that the addition of GGOH and GTPs to an HFD alleviates skeletal muscle atrophy, which is associated with changes in the gut microbiome composition.

Emerging evidence suggests that gut microbiota may serve at the intersection between microbiome-gut-brain and neuroinflammation in the development of neuropathic pain (NP). This study evaluated the effects of curcumin C3 Complex® (CUR) and bisdemethoxy curcumin (CMO), on the composition of gut microbiota and intestinal permeability-/neuroinflammation-associated gene expression in animals with NP. 23 male rats were randomly divided into: sham, spinal nerve ligation (SNL group, pain model), SNL + 100 mg CUR/kg BW (CUR group), and SNL + 50 mg CMO/kg BW (CMO group) for 4 weeks. Fecal samples were collected for microbiota composition analysis using 16S rRNA gene sequencing. The mRNA expression level of tight junction proteins (Claudin-1, Occludin) and neuroinflammation (NF-κB) in the colon, amygdala, and spinal cord using qRT-PCR. Data were analyzed statistically. Using a beta-diversity weighted UniFrac distance metric, the microbiome profile of the CMO-treated group was significantly different than other groups (P < 0.05). Regarding alpha-diversity, while most groups did not differ with respect to richness or evenness the CMO group improved microbiome evenness compared to the SNL group (P = 0.016). The relative abundance of several microbiome amplicon sequence variants (ASV) changed with different treatments. The SNL group showed a depletion in Rothia nasimurium compared to the sham group (P < 0.01). In contrast, Streptococcus and Clostridia ASVs (f_Oscillospiraceae; g_UCG−005) were enriched in the SNL group (P < 0.01). CUR or CMO treatments induced changes in multiple species compared to SNL. CUR and CMO reversed the enrichment effect of SNL on Clostridia ASV (P < 0.01). Compared to the sham group, the SNL group exhibited increased Claudin-1 mRNA expression levels in the amygdala. Relative to the SNL group, both CUR and CMO groups suppressed the mRNA gene expression of Claudin-1 (spinal cord, amygdala), Occludin (spinal cord, colon), and NF-κB (amygdala) in SNL-operated animals. This study suggests CUR and CMO administration modifies multiple species of gut microbiome in an NP model. These effects may be associated with a reduction in SNL-induced intestinal permeability and neuroinflammation. Texas Tech University Health Sciences Center, Lubbock, TX.

Despite the implementation of stringent guidelines for the prevention of catheter-associated (CA) urinary tract infection (UTI), CAUTI remains one of the most common health care-related infections. We previously showed that an antimicrobial/antibiofilm agent inhibited biofilm development by Gram-positive and Gram-negative bacterial pathogens isolated from human infections. In this study, we examined the ability of a novel biofilm preventative agent (BPA) coating on silicone urinary catheters to inhibit biofilm formation on the catheters by six different bacterial pathogens isolated from UTIs: three Escherichia coli strains, representative of the most common bacterium isolated from UTI; one Enterobacter cloacae, a multidrug-resistant isolate; one Pseudomonas aeruginosa, common among patients with long-term catheterization; and one isolate of methicillin-resistant Staphylococcus aureus, as both a Gram-positive and a resistant organism. First, we tested the ability of these strains to form biofilms on urinary catheters made of red rubber, polyvinyl chloride (PVC), and silicone using the microtiter plate biofilm assay. When grown in artificial urine medium, which closely mimics human urine, all tested isolates formed considerable biofilms on all three catheter materials. As the biofilm biomass formed on silicone catheters was 0.5 to 1.6 logs less than that formed on rubber or PVC, respectively, we then coated the silicone catheters with BPA (benzalkonium chloride, polyacrylic acid, and glutaraldehyde), and tested the ability of the coated catheters to further inhibit biofilm development by these uropathogens. Compared with the uncoated silicone catheters, BPA-coated catheters completely prevented biofilm development by all the uropathogens, except P. aeruginosa, which showed no reduction in biofilm biomass. To explore the reason for P. aeruginosa resistance to the BPA coating, we utilized two specific lipopolysaccharide (LPS) mutants. In contrast to their parent strain, the two mutants failed to form biofilms on the BPA-coated catheters, which suggests that the composition of P. aeruginosa LPS plays a role in the resistance of wild-type P. aeruginosa to the BPA coating. Together, our results suggest that, except for P. aeruginosa, BPA-coated silicone catheters may prevent biofilm formation by both Gram-negative and Gram-positive uropathogens.

An increased number antibiotic-resistant bacteria have emerged with the rise in antibiotic use worldwide. As such, there has been a growing interest in investigating novel antibiotics against antibiotic-resistant bacteria. Due to the extensive history of using plants for medicinal purposes, scientists and medical professionals have turned to plants as potential alternatives to common antibiotic treatments. Unlike other antibiotics in use, plant-based antibiotics have the innate ability to eliminate a broad spectrum of microorganisms through phytochemical defenses, including compounds such as alkaloids, organosulfur compounds, phenols, coumarins, and terpenes. In recent years, these antimicrobial compounds have been refined through extraction methods and tested against antibiotic-resistant strains of Gram-negative and Gram-positive bacteria. The results of the experiments demonstrated that plant extracts successfully inhibited bacteria independently or in combination with other antimicrobial products. In this review, we examine the use of plant-based antibiotics for their utilization against antibiotic-resistant bacterial infections. In addition, we examine recent clinical trials utilizing phytochemicals for the treatment of several microbial infections.

Emerging evidence suggests an important role of the gut-brain-axis in the development of neuropathic pain (NP). We investigated the effects of gingerol-enriched ginger (GEG) on pain sensitivity and mRNA expression of inflammation and tight junction protein in GI tissues (colon and ileum) and nervous tissues (amygdala and spinal cord) of animals with NP. Twenty-eight male rats were randomly divided into 5 groups: Naïve control, sham control, spinal nerve ligation (SNL, pain model), SNL + 0.375% (w/w in diet) GEG, and SNL + 0.75% (w/w in diet) GEG for 4 weeks. Pain sensitivity was assessed by von Frey filament tests, evoked audible vocalizations, and grimace tests in subjects. Intestinal permeability was assessed by lactulose/mannitol ratio in urine. The levels of mRNA expression of neuroinflammation (NF-κB) and tight junction (Claudin-1, Zonulin) in colon, ileum, amygdala, and spinal cord were determined by qRT-PCR. Data was analyzed by one-way ANOVA or one-way repeated measures ANOVA followed by post-hoc analysis. Compared to the sham group, the SNL group had significantly greater hypersensitivity (von Frey test), emotional responses (vocalizations), and spontaneous pain (grimace test). GEG supplementation significantly reduced hypersensitivity, emotional responses, and spontaneous pain (nose bulge, whisker change, and ear position) in SNL rats. GEG supplementation tended to decrease intestinal permeability of SNL-operated rats. The SNL group showed a significant increase in mRNA expression of Zonulin in amygdala and Claudin-1 in colon compared to the sham control group. GEG supplementation significantly suppressed the gene expression levels of Zonulin and Claudin-1 in amygdala and colon of SNL animals. GEG addition into the diet suppressed NF-κB gene expression in the amygdala, colon, and ileum of SNL rats. This study suggests GEG supplementation mitigated pain behaviors in a preclinical NP animal model. GEG also decreased SNL-induced neuroinflammation, intestinal permeability, and possible blood-brain barrier breakdown, which may explain the behavioral effects of GEG. USDA-NIFA 2021-67,017-34,026.

Neuroinflammation is a central factor in neuropathic pain (NP). Ginger is a promising bioactive compound in NP management due to its anti-inflammatory property. Emerging evidence suggests that gut microbiome and gut-derived metabolites play a key role in NP. We evaluated the effects of two ginger root extracts rich in gingerols (GEG) and shogaols (SEG) on pain sensitivity, anxiety-like behaviors, circulating cell-free mitochondrial DNA (ccf-mtDNA), gut microbiome composition, and fecal metabolites in rats with NP. Sixteen male rats were divided into four groups: sham, spinal nerve ligation (SNL), SNL+0.75%GEG in diet, and SNL+0.75%SEG in diet groups for 30 days. Compared to SNL group, both SNL+GEG and SNL+SEG groups showed a significant reduction in pain- and anxiety-like behaviors, and ccf-mtDNA level. Relative to the SNL group, both SNL+GEG and SNL+SEG groups increased the relative abundance of Lactococcus, Sellimonas, Blautia, Erysipelatoclostridiaceae, and Anaerovoracaceae, but decreased that of Prevotellaceae UCG-001, Rikenellaceae RC9 gut group, Mucispirillum and Desulfovibrio, Desulfovibrio, Anaerofilum, Eubacterium siraeum group, RF39, UCG-005, Lachnospiraceae NK4A136 group, Acetatifactor, Eubacterium ruminantium group, Clostridia UCG-014, and an uncultured Anaerovoracaceae. GEG and SEG had differential effects on gut-derived metabolites. Compared to SNL group, SNL+GEG group had higher level of 1′-acetoxychavicol acetate, (4E)-1,7-Bis(4-hydroxyphenyl)-4-hepten-3-one, NP-000629, 7,8-Dimethoxy-3-(2-methyl-3-buten-2-yl)-2H-chromen-2-one, 3-{[4-(2-Pyrimidinyl)piperazino]carbonyl}-2-pyrazinecarboxylic acid, 920863, and (1R,3R,7R,13S)-13-Methyl-6-methylene-4,14,16-trioxatetracyclo[11.2.1.0∼1,10∼.0∼3,7∼]hexadec-9-en-5-one, while SNL+SEG group had higher level for (±)-5-[(tert-Butylamino)-2′-hydroxypropoxy]-1_2_3_4-tetrahydro-1-naphthol and dehydroepiandrosteronesulfate. In conclusion, ginger is a promising functional food in the management of NP, and further investigations are necessary to assess the role of ginger on gut-brain axis in pain management.