Pseudomonas aeruginosa: pathogenesis, virulence factors, antibiotic resistance, interaction with host, technology advances and emerging therapeutics

Nucleotide coordinated polymers, a ROS-based immunomodulatory antimicrobial, doubly kill Pseudomonas aeruginosa biofilms of implant infections

Pseudomonas aeruginosa causes high morbidity and mortality in nosocomial infections, and newly approved antibiotics have been declining for decades. A green and universal deprotonation-driven strategy is used to screen the guanylic acid-metal ion coordination polymer nanoparticles (GMC), instead of the failure of binding occurs when specific metal ion participation. We find that the precise pH-dependent oxidase-like activity of GMC-2 orchestrates a duple symphony of immune modulation for Pseudomonas aeruginosa biofilm infections. Specifically, GMC-2-mediated reactive oxygen species (ROS) regulation triggers mitochondrial dysfunction and releases damage-associated molecular patterns, engaging pattern recognition receptors and resulting in endogenous innate immune activation. Meanwhile, GMC-2-triggered ROS generation in a mildly acidic biofilm environment destroys the biofilm, exposing exogenous pathogen-associated molecular patterns. GMC-2 cannot cause resistance for Pseudomonas aeruginosa compared with conventional antibiotics. In an infected implant mouse model, Pseudomonas aeruginosa biofilms were effectively eliminated by GMC-2-mediated triggering of innate and adaptive immunity. These findings provide a universal approach for facilitating the binding of biomolecules with metal ions and highlight the precise ROS-regulating platform plays a critical role in initiating endogenous and exogenous immune activation targeted for bacterial biofilm infection.

ZnO-Rutin nanostructure as a potent antibiofilm agent against Pseudomonasaeruginosa

Pseudomonas aeruginosa is a common human pathogen that is resistant to multiple antibiotics due to its ability to form biofilms. Developing novel nanoformulations capable of inhibiting and removing biofilms offers a promising solution for controlling biofilm-related infections. In this study, we investigated the anti-biofilm activity of rutin-conjugated ZnO nanoparticles (ZnO-Rutin NPs) in pathogenic strains of P. aeruginosa. The synthesized ZnO-Rutin NPs had amorphous shapes with sizes ranging from 14 to 100 nm. The broth microdilution assay revealed that ZnO-Rutin NPs, with an MIC value of 2 mg/mL, exhibit greater antimicrobial activity than ZnO NPs and rutin alone. Based on crystal violet staining, the biofilm inhibition rate by ½ MIC of the conjugated nanoparticles was recorded at above 90 %. The significant reduction in exopolysaccharide (62.75-66.37 %) and alginate (38.3-57.61 %) levels, as well as the formation of thin biofilms in the ZnO-Rutin NP-treated group, confirmed the anti-biofilm potential of these nanoparticles. Additionally, a significant decrease in the metabolic activity and viable cells of mature biofilms was observed after exposure to the conjugated nanoparticles. Furthermore, ZnO-Rutin NPs considerably attenuated the expression of the Las-Rhl quorum-sensing transcriptional regulator genes (lasR and rhlR) in P. aeruginosa by 0.39-0.40 and 0.25-0.42 folds, respectively. This work demonstrated that ZnO-Rutin NPs are remarkably capable of inhibiting the initial stage of biofilm formation and eradicating mature biofilms, suggesting they could be a useful agent for treating P. aeruginosa biofilm-related infections.

The intricate interactions between inflammasomes and bacterial pathogens: Roles, mechanisms, and therapeutic potentials

Inflammasomes are intracellular multiprotein complexes that consist of a sensor, an adaptor, and a caspase enzyme to cleave interleukin (IL)-1β and IL-18 into their mature forms. In addition, caspase-1 and -11 activation results in the cleavage of gasdermin D to form pores, thereby inducing pyroptosis. Activation of the inflammasome and pyroptosis promotes host defense against pathogens, whereas dysregulation of the inflammasome can result in various pathologies. Inflammasomes exhibit versatile microbial signal detection, directly or indirectly, through cellular processes, such as ion fluctuations, reactive oxygen species generation, and the disruption of intracellular organelle function; however, bacteria have adaptive strategies to manipulate the inflammasome by altering microbe-associated molecular patterns, intercepting innate pathways with secreted effectors, and attenuating inflammatory and cell death responses. In this review, we summarize recent advances in the diverse roles of the inflammasome during bacterial infections and discuss how bacteria exploit inflammasome pathways to establish infections or persistence. In addition, we highlight the therapeutic potential of harnessing bacterial immune subversion strategies against acute and chronic bacterial infections. A more comprehensive understanding of the significance of inflammasomes in immunity and their intricate roles in the battle between bacterial pathogens and hosts will lead to the development of innovative strategies to address emerging threats posed by the expansion of drug-resistant bacterial infections.

Exploiting gasdermin-mediated pyroptosis for enhanced antimicrobial activity of phage endolysin against Pseudomonas aeruginosa

Pyroptosis is an inflammatory immune response of eukaryotic cells to bacterial lipopolysaccharide (LPS) and other pathological stimuli, leading to the activation of the gasdermin D (GSDMD) and secretion of pore-forming domain GSDMDNterm, facilitating the release of cytokines. Additionally, GSDMDNterm exhibits antibacterial properties through interactions with bacterial outer membranes (OM). We explored alternative antimicrobial strategy to determine whether inducing natural pyroptosis via GSDMD activation by P. aeruginosa LPS could enhance the effectiveness of recombinant phage endopeptidase KP27 (peptidoglycan-degrading enzyme) against P. aeruginosa, enabling penetration through OM and bacterial killing synergistically. Our findings demonstrated that recombinant GSDMD alone exhibited antibacterial effects against wild-type P. aeruginosa with smooth LPS, while recombinant GSDMDNterm efficiently permeabilized both smooth LPS-bearing and O-chain-deficient P. aeruginosa potentially synergizing with endolysin KP27. Transcriptomic analyses revealed the activation of the immune system pathways in response to LPS, mainly in monocytic cells, in contrast to epithelial A549 or HeLa cell lines. LPS-induced pyroptosis in monocytes led to GSDMD cleavage and the release of interleukins, regardless of the nature/origin of the LPS used. However, the pyroptosis stimulation by LPS in the antibacterial assay was not effective enough for bacterial OM permeabilization and enhancement of endolysin activity. We assume that leveraging pyroptosis induction in monocytic cells to augment the bactericidal activity of endolysins may be limited.

IMPORTANCE

Recombinant GSDMDNterm protein was able to efficiently permeabilize P. aeruginosa outer membranes and increase endolysin activity against bacteria, producing either long LPS O-chains or lack them entirely. The obtained results suggest the limited possibility of using the natural process of pyroptosis occurring in monocytic cells to enhance the bactericidal effect of recombinant phage endolysins against Gram-negative bacteria infection.

Aminopeptidase-Responsive NIR Photosensitizer for Precision Targeting and Eradication of Pseudomonas aeruginosa Biofilms

The emergence of resistance in Pseudomonas aeruginosa represents a significant global health challenge, particularly due to the hurdle of effectively penetrating biofilms with antimicrobials. Moreover, the rise of antibiotic-resistant pathogens has driven the urgent need for developing innovative therapeutic approaches to overcome antibiotic resistance. Antibacterial phototherapy strategies have shown great potential for combating pathogens due to their broad-spectrum antimicrobial activity, spatiotemporal controllability, and relatively low rate of resistance emergence. However, due to the lack of bacterial specificity and penetration, photosensitizers cause considerable damage to mammalian cells and normal tissues and are less effective against bacterial biofilms. Herein, we developed a novel dual-targeting antibacterial strategy to construct a near-infrared photosensitizer, Cy-NEO-Leu. Cy-NEO-Leu showed great bacterial targeting affinity, penetrating and accumulating in biofilms. At the site of infection, it was specifically activated by P. aeruginosa aminopeptidase (PaAP), producing Cy-NEO-NH2, which demonstrated outstanding photothermal (PTT) and photodynamic (PDT) properties, with a photothermal conversion efficiency of up to 70.34%. Both in vitro and in vivo results demonstrated that Cy-NEO-Leu significantly reduced the biofilm biomass and bacterial viability in P. aeruginosa biofilms. Moreover, phototherapy with Cy-NEO-Leu further activated the immune system, enhancing therapeutic efficacy and promoting wound healing. RNA-seq analysis revealed that the antibacterial mechanism of Cy-NEO-Leu-mediated phototherapy involves disruption of the transcriptional and translational processes of P. aeruginosa under laser irradiation. Overall, our results present a promising therapeutic approach against P. aeruginosa biofilms and inspire the development of next-generation antimicrobials.

In-vitro activity of the novel β-lactam/β-lactamase inhibitor combinations and cefiderocol against carbapenem-resistant Pseudomonas spp. clinical isolates collected in Switzerland in 2022

To evaluate the in-vitro activity of the novel commercially-available drugs, including meropenem-vaborbactam (MEV), ceftazidime-avibactam (CZA), ceftolozane-tazobactam (C/T), imipenem-relebactam (IPR) as well as cefiderocol (FDC), against carbapenem-resistant Pseudomonas spp. (CRP) isolates. All CRP isolates collected at the Swiss National Reference Laboratory (NARA) over the year 2022 (n = 170) have been included. Most of these isolates (n = 121) were non-carbapenemase producers. Among the 49 carbapenemase producers, 47 isolates produced metallo-β-lactamases (MBL) including NDM-1 (n = 11), VIM-like (n = 28), IMP-like (n = 7), and both NDM-1 and VIM-2 (n = 1) and two isolates produced the class A carbapenemase GES-5. Susceptibility testing was determined by broth microdilution method (BMD), or disk diffusion test, and results interpreted following EUCAST guidelines. The susceptibility rates for MEV, CZA, C/T and IPR were found to be 41%, 45%, 59% and 58%, respectively, for the whole set of isolates tested. Among non-carbapenemase producers, susceptibility rates for these β-lactam/β-lactamase inhibitors (BL/BLI) combinations were higher, determined at 55%, 61%, 83%, and 82%, respectively. The overall susceptibility of carbapenemase-producing Pseudomonas spp. to novel BL/BLI was relatively low, while 80% of these isolates demonstrated susceptibility to FDC, with a similar proportion (79%) observed among MBL producers. A total of 10 MBL-producing isolates (6%), mainly NDM-1, were found to exhibit resistance to all drugs tested, with the exception of colistin. FDC exhibited an excellent in-vitro activity against this collection of CRP recovered from Switzerland in 2022, including MBL producers. The new BL/BLI combinations displayed significant activity against non-carbapenemase CRP, with IPR and C/T showing the highest susceptibility rates.

Comparative proteomic analysis to annotate the structural association of the hypothetical proteins from the conserved domain of P. aeruginosa as novel vaccine candidates

OBJECTIVES

Pseudomonas aeruginosa, identified as an ESKAPE pathogen, contributes to severe clinical diseases worldwide and despite its prevalence an effective vaccine or treatment remains elusive. Numerous computational methods are being employed to target hypothetical proteins (HPs). Presently, no studies have predicted multi-epitope vaccines for these HPs.

RESULTS

Totally, 877 HPs from P. aeruginosa were included in the study and the data showcased here illustrate a methodical approach to prioritize the proteome by employing diverse comparative proteomics. The study employed physicochemical property assessment and conserved domain analysis to identify stable and immunologically pertinent proteins for epitope prediction. The VaxiJen2.0 antigenicity assessment aided in epitope selection, contributing to the foundational steps in vaccine development by predicting T-cell and B-cell epitopes. Potential T and B cell epitopes with high antigenicity, non-toxic categorization, and robust binding affinities were identified in the investigation. The periplasmic HP WP_132813935.1 was predicted as conserved, stable, and soluble. The T-cell peptide RTSMRALAY and the B-cell peptide MPVYLYLM were predicted to be probable non-allergen and demonstrated strong binding with MHC class I allele HLA-C*03:03.

CONCLUSIONS

This research provides a comprehensive approach to predict T and B cell epitopes for conditions associated with P. aeruginosa, offering a candidate pool for tailored vaccine development. However, the efficacy of these epitopes in vaccine development necessitates clinical validation and testing for confirmation.

Chitosan-casein as novel drug delivery system for transferring Phyllanthus emblica to inhibit Pseudomonas aeruginosa

This study investigated the ability of Phyllanthus emblica encapsulated within chitosan-coated casein (CS-casein-Amla) nanoparticles to inhibit the growth of multi-drug-resistant Pseudomonas aeruginosa (P. aeruginosa) bacteria and prevent the formation of biofilms. The MDR strains underwent screening, and the morphological characteristics of the resulting nanoparticles were assessed using SEM, DLS, and FTIR. In addition, the efficacy of encapsulation, stability, and drug release were evaluated. The PpgL, BdlA, and GacA biofilm gene transcription quantities were quantified by quantitative real-time PCR. Simultaneously, the nanoparticles were assessed for their antibacterial and cytotoxic effects using the well diffusion and MTT procedures. CS-casein-Amla nanoparticles with a size of 500.73 ± 13 nm, encapsulation efficiency of 76.33 ± 0.81%, and stability for 60 days at 4 °C (Humidity 30%) were created. The biological analysis revealed that CS-casein-Amla nanoparticles exhibited strong antibacterial properties. This was shown by their capacity to markedly reduce the transcription of PpgL, BdlA, and GacA biofilm genes at a statistically significant value of p ≤ 0.01. The nanoparticles demonstrated decreased antibiotic resistance compared to unbound Amla and CS-casein. Compared to Amla, CS-casein-Amla nanoparticles showed very little toxicity against HDF cells at dosages ranging from 1.56 to 100 µg/mL (p ≤ 0.01). The results highlight the potential of CS-casein-Amla nanoparticles as a significant advancement in combating highly resistant P. aeruginosa. The powerful antibacterial properties of CS-casein-Amla nanoparticles against P. aeruginosa MDR strains, which are highly resistant pathogens of great concern, may catalyze the development of novel antibacterial research approaches.

Development and application of hydrogels in pathogenic bacteria detection in foods

Hydrogels are 3D networks of water-swollen hydrophilic polymers. It possesses unique properties (e.g., carrying biorecognition elements and creating a micro-environment) that make it highly suitable for bacteria detection (e.g., expedited and effective bacteria detection) and mitigation of bacterial contamination in specific environments (e.g., food systems). This study first introduces the materials used to create hydrogels for bacteria detection and the mechanisms for detection. We also summarize different hydrogel-based detection methods that rely on external stimuli and biorecognition elements, such as enzymes, temperature, pH, antibodies, and oligonucleotides. Subsequently, a range of widely utilized bacterial detection technologies were discussed where recently hydrogels are being used. These modifications allow for precise, real-time diagnostics across varied food matrices, responding effectively to industry needs for sensitivity, scalability, and portability. After highlighting the utilization of hydrogels and their role in these detection techniques, we outline limitations and advancements in the methods for the detection of foodborne pathogenic bacteria, especially the potential application of hydrogels in the food industry.

Resilience and Charge-Dependent Fibrillation of functional amyloid: Interactions of Pseudomonas Biofilm-Associated FapB and FapC Amyloids

FapC and FapB are biofilm-associated amyloids involved in the virulence of Pseudomonas and other bacteria. We herein demonstrate their exceptional thermal and chemical resilience, suggesting that their biofilm structures might withstand standard sterilization, thereby contributing to the persistence of P. aeruginosa infections. Our findings also underscore the impact of environmental factors on Fap proteins, suggesting that orthologs in different Pseudomonas strains adapt to specific environments and roles. Challenging previous assumptions about a simple nucleation role for FapB in promoting FapC aggregation, the study shows a significant influence of FapC on FapB aggregation. The interaction between these FapB and FapC is intricate: FapB stabilizes FapC fibrils, while FapC slows down FapB fibrillation but can still serve as a cross-seeding template. This complex interplay is key to understanding their roles in bacterial biofilms. Furthermore, the study highlights distinct differences between Fap and E. coli's CsgA (curli) amyloid, where CsgB assumes a simple unidirectional role in nucleating CsgA fibrillation, emphasizing the importance of a comprehensive understanding of various amyloid systems. This knowledge is vital for developing effective intervention strategies against bacterial infections and leveraging the unique properties of these amyloids in technological applications such as novel bio-nanomaterials or protective coatings.

Framework nucleic acid strategy enables closer microbial contact for programming short-range interaction

Programming precise and specific microbial intraspecies or interspecies interaction would be powerful for microbial metabolic regulation, signal pathway mechanism understanding, and therapeutic application. However, it is still of great challenge to develop a simple and universal method to artificially encode the microbial interactions without interfering with the intrinsic cell metabolism. Here, we proposed an extensible and flexible framework nucleic acid strategy for encoding the specific and precise microbial interactions upon self-assembly. With this spatial manipulation tool, we propose the microbial spatial heterogeneity and short-range interaction mechanism that the microbial assembly facilitates the gene expressions of the surface sensors including flagella and pili in Pseudomonas aeruginosa, leading to a more sensitive response to quorum sensing. The microbial interaction programming strategy proposed in this work is expected to provide a powerful and designable nanoplatform for better understanding of distance-dependent bacterial communication networks.

The histidine kinase NahK regulates denitrification and nitric oxide accumulation through RsmA in Pseudomonas aeruginosa

Pseudomonas aeruginosa have a versatile metabolism; they can adapt to many stressors, including limited oxygen and nutrient availability. This versatility is especially important within a biofilm where multiple microenvironments are present. As a facultative anaerobe, P. aeruginosa can survive under anaerobic conditions utilizing denitrification. This process produces nitric oxide (NO) which has been shown to result in cell elongation. However, the molecular mechanism underlying this phenotype is poorly understood. Our laboratory has previously shown that NosP is a NO-sensitive hemoprotein that works with the histidine kinase NahK to regulate biofilm formation in P. aeruginosa. In this study, we identify NahK as a novel regulator of denitrification under anaerobic conditions. Under anaerobic conditions, deletion of nahK leads to a reduction of growth coupled with reduced transcriptional expression and activity of the denitrification reductases. Furthermore, during stationary phase under anaerobic conditions, ΔnahK does not exhibit cell elongation, which is characteristic of P. aeruginosa. We determine the loss of cell elongation is due to changes in NO accumulation in ΔnahK. We further provide evidence that NahK may regulate denitrification through modification of RsmA levels.

IMPORTANCE

Pseudomonas aeruginosa is an opportunistic multi-drug resistance pathogen that is associated with hospital-acquired infections. P. aeruginosa is highly virulent, in part due to its versatile metabolism and ability to form biofilms. Therefore, better understanding of the molecular mechanisms that regulate these processes should lead to new therapeutics to treat P. aeruginosa infections. The histidine kinase NahK has been previously shown to be involved in both nitric oxide (NO) signaling and quorum sensing through RsmA. The data presented here demonstrate that NahK is responsive to NO produced during denitrification to regulate cell morphology. Understanding the role of NahK in metabolism under anaerobic conditions has larger implications in determining its role in a heterogeneous metabolic environment such as a biofilm.

Regulation of TCA cycle genes by srbA sRNA: Impacts on Pseudomonas aeruginosa virulence and survival

Pseudomonas aeruginosa, an opportunistic bacterial pathogen of public health concern, is known for its metabolic versatility, adaptability in harsh environment, and pathogenic aggressiveness. P. aeruginosa relies on various regulatory networks modulated by small non-coding RNAs, which in turn influence different physiological traits such as metabolism, stress response, and pathogenesis. In this study, srbA sRNA has been shown to play a diverse role in regulating cellular metabolism and the production of different virulence factors in P. aeruginosa. srbA was found to control the TCA cycle, a key regulatory pathway for cellular metabolism and energy production, by regulating three main enzymes: citrate synthase (gltA), isocitrate dehydrogenase (icd), and α-ketoglutarate dehydrogenase E1 subunit (sucA) at both the transcriptional and translational levels. By modulating the TCA cycle, srbA could help the bacteria to adapt nutritional stress by lowering energy consumption. Additionally, srbA has been found to differentially regulate production of various virulence factors such as rhamnolipid, elastase, LasA protease, and pyocyanin under both nutrient-rich and nutrient-limiting conditions. It could also influence motilities in P. aeruginosa, linked to biofilm formation and pathogenicity. Thus, srbA might hold a promise in the research area for identifying virulence pathways and developing novel therapeutic targets to combat the global pathogenic threat of P. aeruginosa.

Exploring the metabolic potential of Aeromonas to utilise the carbohydrate polymer chitin

Members of the Aeromonas genus are commonly found in natural aquatic ecosystems. However, they are also frequently present in non-chlorinated drinking water distribution systems. High densities of these bacteria indicate favorable conditions for microbial regrowth, which is considered undesirable. Studies have indicated that the presence of Aeromonas is associated with loose deposits and the presence of invertebrates, specifically Asellus aquaticus. Therefore, a potential source of energy in these nutrient poor environments is chitin, the structural shell component in these invertebrates. In this study, we demonstrate the ability of two Aeromonas strains, commonly encountered in drinking water distribution systems, to effectively degrade and utilize chitin as a sole carbon and nitrogen source. We conducted a quantitative proteomics study on the cell biomass and secretome from pure strain cultures when switching the nutrient source from glucose to chitin, uncovering a diverse array of hydrolytic enzymes and metabolic pathways specifically dedicated to the utilization of chitin. Additionally, a genomic analysis of different Aeromonas species suggests the general ability of this genus to degrade and utilize a variety of carbohydrate biopolymers. This study indicates the relation between the utilization of chitin by Aeromonas and their association with invertebrates such as A. aquaticus in loose deposits in drinking water distribution systems.

Current Progress in the Development of mRNA Vaccines Against Bacterial Infections

Bacterial infections have accompanied humanity for centuries. The discovery of the first antibiotics and the subsequent golden era of their discovery temporarily shifted the balance in this confrontation to the side of humans. Nevertheless, the excessive and improper use of antibacterial drugs and the evolution of bacteria has gotten the better of humans again. Therefore, today, the search for new antibacterial drugs or the development of alternative approaches to the prevention and treatment of bacterial infections is relevant and topical again. Vaccination is one of the most effective strategies for the prevention of bacterial infections. The success of new-generation vaccines, such as mRNA vaccines, in the fight against viral infections has prompted many researchers to design mRNA vaccines against bacterial infections. Nevertheless, the biology of bacteria and their interactions with the host's immunity are much more complex compared to viruses. In this review, we discuss structural features and key mechanisms of evasion of an immune response for nine species of bacterial pathogens against which mRNA vaccines have been developed and tested in animals. We focus on the results of experiments involving the application of mRNA vaccines against various bacterial pathogens in animal models and discuss possible options for improving the vaccines' effectiveness. This is one of the first comprehensive reviews of the use of mRNA vaccines against bacterial infections in vivo to improve our knowledge.

Preparation and Biological Activity of Lignin-Silver Hybrid Nanoparticles

Silver nanoparticles (AgNPs) are excellent antimicrobial agents and promising candidates for preventing or treating bacterial infections caused by antibiotic resistant strains. However, their increasing use in commercial products raises concerns about their environmental impact. In addition, traditional physicochemical approaches often involve harmful agents and excessive energy consumption, resulting in AgNPs with short-term colloidal stability and silver ion leaching. To address these issues, we designed stable hybrid lignin-silver nanoparticles (AgLigNPs) intended to effectively hit bacterial envelopes as a main antimicrobial target. The lignin nanoparticles (LigNPs), serving as a reducing and stabilizing agent for AgNPs, have a median size of 256 nm and a circularity of 0.985. These LigNPs were prepared using the dialysis solvent exchange method, producing spherical particles stable under alkaline conditions and featuring reducing groups oriented toward a wrinkled surface, facilitating AgNPs synthesis and attachment. Maximum accumulation of silver on the LigNP surface was observed at a mass reaction ratio mAg:mLig of 0.25, at pH 11. The AgLigNPs completely inhibited suspension growth and reduced biofilm development by 50% in three tested strains of Pseudomonas aeruginosa at a concentration of 80/9.5 (lignin/silver) mg L-1. Compared to unattached AgNPs, AgLigNPs required two to eight times lower silver concentrations to achieve complete inhibition. Additionally, our silver-containing nanosystems were effective against bacteria at safe concentrations in HEK-293 and HaCaT tissue cultures. Stability experiments revealed that the nanosystems tend to aggregate in media used for bacterial cell cultures but remain stable in media used for tissue cultures. In all tested media, the nanoparticles retained their integrity, and the presence of lignin facilitated the prevention of silver ions from leaching. Overall, our data demonstrate the suitability of AgLigNPs for further valorization in the biomedical sector.

Antibiotic resistance of bioaerosols in particulate matter from indoor environments of the hospitals in Dhaka Bangladesh

The emergence and spread of antibiotic resistance in microorganisms pose significant challenges to public health, especially in hospitals. This study investigated the existence or occurrence of bacterial bioaerosol and their antibiotic resistance patterns in particulate matter (PM) collected from hospitals in the greater Dhaka region, Bangladesh. The real-time particulate matter concentrations (PM1.0, PM2.5, and PM10) were measured in four hospitals and two ambient locations. Air sampling was conducted using a filter-based method with a low-volume air sampler, while AEROCET-531 S (USA) was employed to monitor particulate matter concentrations. Bacterial bioaerosol concentration was determined using a culture-based method, and eleven bacterial species, including nine individual species, i.e., Staphylococcus aureus, Pseudomonas aeruginosa, P. stutzeri, Bacillus cereus, Acinetobacter schindleri, Proteus vulgaris, B. subtilis, Escherichia coli, and B. aerius, were isolated. Antibiotic susceptibility testing was conducted using the Kirby-Bauer disk diffusion method with 21 antibiotics. Bacterial isolates were detected using partial sequencing of the 16 S rRNA gene. Bioaerosol concentration ranged from 194.65 ± 22.48 CFU/m3 to 948.39 ± 84.14 CFU/m3, showing significant correlations with PM1.0 and PM2.5 concentrations (R2 = 0.80 and 0.85, respectively). All bacterial isolates collected from the hospitals exhibited resistance against four or more antibiotics, indicating multidrug resistance (MDR). Notably, the bacterial isolates displayed the highest resistance rate against ampicillin (90.90%), azithromycin (81.81%), erythromycin (81.81%), cefixime (81.81%), and cotrimoxazole (54.54%), among the tested antibiotics. Except B. aerius, all other bacterial isolates were associated with hospital-acquired infections (HAIs). These findings highlight the high rates of antibiotic resistance, underscoring the pressing requirement for infection control measures and continuous surveillance strategies in hospital settings. These findings emphasize the necessity for global hospital infection control strategies focusing airborne multidrug-resistant microorganisms.

Palmitoleic acid inhibits Pseudomonas aeruginosa quorum sensing activation and protects lungs from infectious injury

BACKGROUND

Unsaturated fatty acids targeting quorum sensing (QS) system have shown potential application in reducing bacterial virulence. We aim to investigate the effect of palmitoleic acid (PMA) on P. aeruginosa QS activation, and its impact on infection-induced lung injury.

METHODS

The influence of PMA on QS signaling molecule (3OC12-HSL and C4-HSL) concentrations, pyocyanin production, and QS gene transcription levels were examined in wildtype PAO1 culture. The roles of PMA in reducing infection-induced injury were assessed in human bronchial epithelial BEAS-2B cells and mouse lung infection models, respectively. PMA levels and QS signaling molecule concentrations were tested in the bronchoalveolar lavage fluid (BALF) of bronchiectasis patients with first-time detection of P. aeruginosa infection.

RESULTS

PMA administration dose-dependently suppressed the expression of QS signaling molecules, pyocyanin, and QS genes during the logarithmic stage of bacterial growth. In BEAS-2B cells, PMA-treated PAO1 filtrates significantly reduced cell apoptosis and expression of IL-8 and IL-6. In mouse lung infection models, prophylactically oral administration of PMA significantly downregulated the expression of P. aeruginosa QS signals and QS genes (lasR, rhlR, rhlI, lasB, rhlA, phzA1, phnA) in lungs, and relieved neutrophilic airway inflammation. Finally, PMA levels were negatively correlated with the concentrations of both 3OC12-HSL and C4-HSL in BALF of bronchiectasis patients, and positively correlated with their forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1.0).

CONCLUSION

Our findings show that PMA inhibits P. aeruginosa QS activation and protects lungs from injury caused by bacterial virulence. Hence, PMA may serve as a potential anti-QS agent against P. aeruginosa infection and would help to alleviate lung injury in bronchiectasis patients.

Quercetin: a promising virulence inhibitor of Pseudomonas aeruginosa LasB in vitro

With the inappropriate use of antibiotics, antibiotic resistance has emerged as a major dilemma for patients infected with Pseudomonas aeruginosa. Elastase B (LasB), a crucial extracellular virulence factor secreted by P. aeruginosa, has been identified as a key target for antivirulence therapy. Quercetin, a natural flavonoid, exhibits promising potential as an antivirulence agent. We aim to evaluate the impact of quercetin on P. aeruginosa LasB and elucidate the underlying mechanism. Molecular docking and molecular dynamics simulation revealed a rather favorable intermolecular interaction between quercetin and LasB. At the sub-MICs of ≤256 μg/ml, quercetin was found to effectively inhibit the production and activity of LasB elastase, as well as downregulate the transcription level of the lasB gene in both PAO1 and clinical strains of P. aeruginosa. Through correlation analysis, significant positive correlations were shown between the virulence gene lasB and the QS system regulatory genes lasI, lasR, rhlI, and rhlR in clinical strains of P. aeruginosa. Then, we found the lasB gene expression and LasB activity were significantly deficient in PAO1 ΔlasI and ΔlasIΔrhlI mutants. In addition, quercetin significantly downregulated the expression levels of regulated genes lasI, lasR, rhlI, rhlR, pqsA, and pqsR as well as effectively attenuated the synthesis of signaling molecules 3-oxo-C12-HSL and C4-HSL in the QS system of PAO1. Quercetin was also able to compete with the natural ligands OdDHL, BHL, and PQS for binding to the receptor proteins LasR, RhlR, and PqsR, respectively, resulting in the formation of more stabilized complexes. Taken together, quercetin exhibits enormous potential in combating LasB production and activity by disrupting the QS system of P. aeruginosa in vitro, thereby offering an alternative approach for the antivirulence therapy of P. aeruginosa infections. KEY POINTS: • Quercetin diminished the content and activity of LasB elastase of P. aeruginosa. • Quercetin inhibited the QS system activity of P. aeruginosa. • Quercetin acted on LasB based on the QS system.

Effectiveness of water system chemical disinfection against Pseudomonas aeruginosa infections, despite a not-so-obvious connection

BACKGROUND

Pseudomonas aeruginosa is a well-recognized opportunistic pathogen frequently responsible for hospital-acquired infections. Acquisition routes of P aeruginosa are both endogenous and exogenous, including transmission from a portion of the hospital water system.

METHODS

The impact of disinfection procedures of the water system and description routes of P aeruginosa transmission in a surgical intensive care unit over a 2-year period were investigated. Two distinct periods A and B were considered, respectively, before and after the disinfection. Fourier transform infrared spectroscopy was used to compare isolates recovered from patients and tap water.

RESULTS

Overall, 21.3% of tap water samples were positive but with a significantly lower rate in period B. Concomitantly, the prevalence of patients positive for P aeruginosa decreased from 2.6% to 1%, suggesting a correlation between the presence of environmental sources and patient contaminations. The results revealed that 18% of patients were involved in cross-transmission events not related to any isolate recovered from water, suggesting transmission through care practices. Conversely, only 1 environmental transmission event was suspected in a patient.

CONCLUSIONS

Although the link between the hospital environment and patients was unclear, HCW-associated care practices could be related to contaminated point-of-use waters and then indirect spreading to patients.

Successful phage-antibiotic therapy of P. aeruginosa implant-associated infection in a Siamese cat

Antibiotic-resistant pathogens are a growing global issue, leading to untreatable infectious diseases in both humans and animals. Personalized bacteriophage (phage) therapy, the use of specific anti-bacterial viruses, is currently a leading approach to combat antibiotic-resistant infections. The implementation of phage therapy has primarily been focused on humans, almost neglecting the impact of such infections on the health and welfare of companion animals. Pets also have the potential to spread resistant infections to their owners or the veterinary staff through zoonotic transmission. Here, we showcase personalized phage-antibiotic treatment of a cat with a multidrug-resistant Pseudomonas aeruginosa implant-associated infection post-arthrodesis surgery. The treatment encompassed a tailored combination of an anti-P. aeruginosa phage and ceftazidime, precisely matched to the pathogen. The phage was topically applied to the surgical wound while the antibiotic was administered intramuscularly. After two treatment courses spanning 7 and 3 weeks, the surgical wound, which had previously remained open for five months, fully closed. To the best of our knowledge, this is the first case of personalized phage therapy application in felines, which provides further evidence of the effectiveness of this approach. The successful outcome paves the way for personalized phage-antibiotic treatments against persistent infections therapy in veterinary practice.

Cleavage of cell junction proteins as a host invasion strategy in leptospirosis

Infection and invasion are the prerequisites for developing the disease symptoms in a host. While the probable mechanism of host invasion and pathogenesis is known in many pathogens, very little information is available on Leptospira invasion/pathogenesis. For causing systemic infection Leptospira must transmigrate across epithelial barriers, which is the most critical and challenging step. Extracellular and membrane-bound proteases play a crucial role in the invasion process. An extensive search for the proteins experimentally proven to be involved in the invasion process through cell junction cleavage in other pathogens has resulted in identifying 26 proteins. The similarity searches on the Leptospira genome for counterparts of these 26 pathogenesis-related proteins identified at least 12 probable coding sequences. The proteins were either extracellular or membrane-bound with a proteolytic domain to cleave the cell junction proteins. This review will emphasize our current understanding of the pathogenic aspects of host cell junction-pathogenic protein interactions involved in the invasion process. Further, potential candidate proteins with cell junction cleavage properties that may be exploited in the diagnostic/therapeutic aspects of leptospirosis will also be discussed. KEY POINTS: • The review focussed on the cell junction cleavage proteins in bacterial pathogenesis • Cell junction disruptors from Leptospira genome are identified using bioinformatics • The review provides insights into the therapeutic/diagnostic interventions possible.

Microbiome analysis reveals the inducing effect of Pseudomonas on prostatic hyperplasia via activating NF-κB signalling

Benign prostatic hyperplasia (BPH) is a prevalent disease among middle-aged and elderly males, but its pathogenesis remains unclear. Dysbiosis of the microbiome is increasingly recognized as a significant factor in various human diseases. Prostate tissue also contains a unique microbiome, and its dysbiosis has been proposed to contribute to prostate diseases. Here, we obtained prostate tissues and preoperative catheterized urine from 24 BPH individuals, and 8 normal prostate samples as controls, which followed strict aseptic measures. Using metagenomic next-generation sequencing (mNGS), we found the disparities in the microbiome composition between normal and BPH tissues, with Pseudomonas significantly enriched in BPH tissues, as confirmed by fluorescence in situ hybridization (FISH). Additionally, we showed that the prostate microbiome differed from the urine microbiome. In vitro experiments revealed that lipopolysaccharide (LPS) of Pseudomonas activated NF-κB signalling, leading to inflammation, proliferation, and EMT processes, while inhibiting apoptosis in prostatic cells. Overall, our research determines the presence of microbiome dysbiosis in BPH, and suggests that Pseudomonas, as the dominant microflora, may promote the progression of BPH through LPS activation of NF-κB signalling.

Unitig-centered pan-genome machine learning approach for predicting antibiotic resistance and discovering novel resistance genes in bacterial strains

In current genomic research, the widely used methods for predicting antimicrobial resistance (AMR) often rely on prior knowledge of known AMR genes or reference genomes. However, these methods have limitations, potentially resulting in imprecise predictions owing to incomplete coverage of AMR mechanisms and genetic variations. To overcome these limitations, we propose a pan-genome-based machine learning approach to advance our understanding of AMR gene repertoires and uncover possible feature sets for precise AMR classification. By building compacted de Brujin graphs (cDBGs) from thousands of genomes and collecting the presence/absence patterns of unique sequences (unitigs) for Pseudomonas aeruginosa, we determined that using machine learning models on unitig-centered pan-genomes showed significant promise for accurately predicting the antibiotic resistance or susceptibility of microbial strains. Applying a feature-selection-based machine learning algorithm led to satisfactory predictive performance for the training dataset (with an area under the receiver operating characteristic curve (AUC) of > 0.929) and an independent validation dataset (AUC, approximately 0.77). Furthermore, the selected unitigs revealed previously unidentified resistance genes, allowing for the expansion of the resistance gene repertoire to those that have not previously been described in the literature on antibiotic resistance. These results demonstrate that our proposed unitig-based pan-genome feature set was effective in constructing machine learning predictors that could accurately identify AMR pathogens. Gene sets extracted using this approach may offer valuable insights into expanding known AMR genes and forming new hypotheses to uncover the underlying mechanisms of bacterial AMR.

Citrus flavonoids diosmin, myricetin and neohesperidin as inhibitors of Pseudomonas aeruginosa: Evidence from antibiofilm, gene expression and in vivo analysis

Citrus flavonoids are group of bioactive polyphenols. Here, we investigated the potential of diosmin, myricetin and neohesperidin as possible inhibitors of Pseudomonas aeruginosa. This bacterium is a major clinical challenge due to its propensity to form resistant biofilm. The aims of this study were to examine flavonoids antibacterial activity using the microdilution method, assays intended to determine several antibiofilm mechanisms (crystal violet, congo red binding, extracellular DNA (eDNA) test and confocal laser scanning microscopy (CLSM) live/dead cell imaging), followed by virulence genes RT-qPCR analysis. Furthermore, we aimed to examine in vivo toxicity of the compounds as well as their efficacy in P. aeruginosa zebrafish embryo infection model. Minimal inhibitory concentrations of tested flavonoids towards P. aeruginosa were in range 0.05 - 0.4 mg/mL. A high potential of the compounds to disturb both the formation of the bacterial biofilm and its eradication was recorded, including significant reduction in biofilm biomass, exopolysaccharide and eDNA production. Biofilm treatment with diosmin resulted in the lowest percentage of live microbial cells as observed in the CLSM live/dead cell imaging. The lasI, pvdS, and rhlC genes were found to be downregulated in the presence of diosmin and myricetin. Only diosmin stood out as non-embryotoxic. Consequently, in vivo analysis using a zebrafish model of P. aeruginosa infection showed an antivirulence effect of diosmin. Our findings suggest that diosmin could be potential candidate for the development of new agent that target P. aeruginosa infections by reducing its virulence mechanisms.

Antibacterial potential of Euphorbia canariensis against Pseudomonas aeruginosa bacteria causing respiratory tract infections

The widespread dissemination of bacterial resistance has led to great attention being paid to finding substitutes for traditionally used antibiotics. Plants are rich in various phytochemicals that could be used as antibacterial therapies. Here, we elucidate the phytochemical profile of Euphorbia canariensis ethanol extract (EMEE) and then elucidate the antibacterial potential of ECEE against Pseudomonas aeruginosa clinical isolates. ECEE showed minimum inhibitory concentrations ranging from 128 to 512 µg/mL. The impact of ECEE on the biofilm-forming ability of the tested isolates was elucidated using crystal violet assay and qRT-PCR to study its effect on the gene expression level. ECEE exhibited antibiofilm potential, which resulted in a downregulation of the expression of the biofilm genes (algD, pelF, and pslD) in 39.13% of the tested isolates. The antibacterial potential of ECEE was studied in vivo using a lung infection model in mice. A remarkable improvement was observed in the ECEE-treated group, as revealed by the histological and immunohistochemical studies. Also, ELISA showed a noticeable decrease in the oxidative stress markers (nitric oxide and malondialdehyde). The gene expression of the proinflammatory marker (interleukin-6) was downregulated, while the anti-inflammatory biomarker was upregulated (interleukin-10). Thus, clinical trials should be performed soon to explore the potential antibacterial activity of ECEE, which could help in our battle against resistant pathogenic bacteria.

Antibiotic resistance genes and virulence factors in the plastisphere in wastewater treatment plant effluent: Health risk quantification and driving mechanism interpretation

Microplastics (MPs) are ubiquitous in wastewater treatment plants (WWTPs) and provide a unique niche for the spread of pollutants. To date, risk assessments and driving mechanisms of pathogens, antibiotic resistance genes (ARGs), and virulence factors (VFs) in the plastisphere are still lacking. Here, the microbiota, ARGs, VFs, their potential health risks, and biologically driving mechanisms on polythene (PE), polyethylene terephthalate (PET), poly (butyleneadipate-co-terephthalate) and polylactic acid blends (PBAT/PLA), PLA MPs, and gravel in WWTP effluent were investigated. The results showed that plastisphere and gravel biofilm harbored more distinctive microorganisms, promoting the uniqueness of pathogens, ARGs, and VFs compared to WWTP effluent. The abundance of major pathogens, ARGs, and VFs in the plastisphere was 1.01-1.35 times higher than that in the effluent. The high health risk of ARGs (HRA) calculated by fully considering the abundance, clinical relevance, pathogenicity, accessibility and mobility, and the high proportion of resistance contigs with mobile genetic elements confirmed that the plastisphere posed the highest potential health risk. Candidatus Microthrix and Candidatus Promineifilum were the essential hosts of ARGs and VFs in the plastisphere and gravel biofilm, respectively. High metabolic activity such as amino acid metabolism and biosynthesis of secondary metabolites, and highly expressed key genes increased the synthesis of ARGs and VFs. The primary mechanisms driving ARG enrichment in the plastisphere were enhanced microbial metabolic activity, increased frequency of horizontal gene transfer, heightened antibiotic inactivation and efflux, and reduced cell permeability. This study provided new insights into the ARGs, VFs, and health risks of the plastisphere and emphasized the importance of strict control of wastewater discharge.

Therapeutic efficacy of chitosan-based hybrid nanomaterials to treat microbial biofilms and their infections - A review

Antimicrobial resistance, the biggest issue facing the global healthcare sector, quickly emerged and spread due to the frequent use of antibiotics in regular treatments. The investigation of polymer-based nanomaterials as possible antibiofilm treatment agents is prompted by the growing ineffectiveness of conventional therapeutic techniques against these resistant bacteria species. So far, several articles have been published on microbial biofilm eradication using various polymer-based nanomaterials due to their therapeutic efficacy and biocompatibility nature. Despite their potential, a comprehensive review of the chitosan-based hybrid nanomaterials to treat microbial biofilms and their infections is lacking. This review provides a comprehensive investigation of the current state of therapeutic efficacy, various nanoformulations, advantages, limitations, and regulations of chitosan-based hybrid nanomaterials for biofilm treatment. Special attention is given to the application of chitosan-based nanomaterials in wound care, urinary tract infections, and dental biofilms are discussed, highlighting their role in managing biofilm-associated complications. Researchers will be better able to comprehend and develop unique, marketable chitosan-based nanomaterials with increased activity to treat biofilm infections in near future with the aid of this review.

Myrtus communis leaf compounds as novel inhibitors of quorum sensing-regulated virulence factors and biofilm formation: In vitro and in silico investigations

Antibiotic resistance of the Gram-negative bacterium Pseudomonas aeruginosa and its ability to form biofilm through the Quorum Sensing (QS) mechanism are important challenges in the control of infections caused by this pathogen. The extract of Myrtus communis (myrtle) showed strong anti-QS effect on C hromobacterium . violaceum 6267 by inhibiting 80 % of the production of violacein pigment at a sub-MIC concentration of 1/8 (31.25 μg/mL). In addition, the extract exhibited an inhibitory effect on virulence factors of P. aeruginosa PAO1 at half MIC (125 μg/mL), significantly reducing the formation of biofilms (72.02 %), the swarming activity (75 %), and the production of protease (61.83 %) and pyocyanin (97 %). The active fraction also downregulated the expression of selected regulatory genes involved in the biofilm formation and QS in the P. aeruginosa PAO1 strain. These genes included the autoinducer synthase genes (lasI and rhlI), the genes involved in the expression of their corresponding receptors (lasR and rhlR), and the pqsA genes. The analysis of the active fraction by HPLC/UV/MS and NMR allowed the identification of three phenolic compounds, 3,5-di-O-galloylquinic acid, myricetin 3-O-α-l-rhamnopyranoside (myricitrin), and myricetin 3-O-(2″-O-galloyl)-ß-d-galactopyranoside. In silico studies showed that 3,5-di-O-galloylquinic acid, with an affinity score of -9.20 kcal/mol, had the highest affinity to the active site of the CviR protein (3QP8), a QS receptor from C. violaceum. Additionally, myricetin 3-O-α-l-rhamnopyranoside (myricitrin) and myricetin 3-O-(2″-O-galloyl)-ß-d-galactopyranoside interact to a lesser extent with 3QP8. In conclusion, this study contributed significantly to the discovery of new QS inhibitors from M. communis leaves against resistant Gram-negative pathogens.

Seasonal and spatial variations in concentration, diversity, and antibiotic resistance of ambient bioaerosols in an arid region

The airborne microbiome significantly influences human health and atmospheric processes within Earth's troposphere and is a crucial focus for scientific research. This study aimed to analyze the composition, diversity, distribution, and spatiotemporal characteristics of airborne microbes in Qatar's ambient air. Air samples were collected using a sampler from ten geographically or functionally distinct locations during a period of one year. Spatial and seasonal variations significantly impacted microbial concentrations, with the highest average concentrations observed at 514 ± 77 CFU/m3 for bacteria over the dry-hot summer season and 134 ± 31 CFU/m3 for fungi over the mild winter season. Bacterial concentrations were notably high in 80% of the locations during the dry-hot summer sampling period, while fungal concentrations peaked in 70% of the locations during winter. The microbial diversity analysis revealed several health-significant bacteria including the genera Chryseobacterium, Pseudomonas, Pantoea, Proteus, Myroides, Yersinia, Pasteurella, Ochrobactrum, Vibrio, and fungal strains relating to the genera Aspergillus, Rhizopus Fusarium, and Penicillium. Detailed biochemical and microscopic analyses were employed to identify culturable species. The strongest antibiotic resistance (ABR) was observed during the humid-hot summer season, with widespread resistance to Metronidazole. Health risk assessments based on these findings indicated potential risks associated with exposure to high concentrations of specific bioaerosols. This study provides essential baseline data on the natural background concentrations of bioaerosols in Qatar, offering insights for air quality assessments and forming a basis for public health policy recommendations, particularly in arid regions.

Rapid detection of imipenem/relebactam susceptibility/resistance in Pseudomonas aeruginosa

OBJECTIVES

Imipenem-relebactam (IPR) has been reported to exhibit a good activity against non-metallo-ß-lactamase carbapenem-resistant Pseudomonas aeruginosa (CRPA), and the rapid detection of susceptibility/resistance to this new therapeutic alternative may be crucial. Therefore, the Rapid IPR Pseudomonas NP test was developed to quickly identify IPR susceptibility/resistance among multidrug-resistant P. aeruginosa.

METHODS

The principle of the Rapid IPR Pseudomonas NP test is based on visually detecting glucose metabolization by observing (or not) a color change from yellow to red or orange of the red phenol pH indicator in the presence of imipenem at 2 mg/L and relebactam at 4 mg/L A total of 80 clinical Pseudomonas aeruginosa isolates were analyzed, among which 42 isolates were IPR resistant according to EUCAST guidelines (MICs, susceptible ≤2 mg/L, resistant >2 mg/L). Results obtained with the Rapid IPR Pseudomonas NP test were compared with the reference broth microdilution (BMD).

RESULTS

The sensitivity, specificity and accuracy of the test were found to be 100 %, 89.5 % and 95 %, respectively, using the BMD reference method as a comparator. Moreover, five out of the IPR-susceptible isolates (n = 38) exhibiting an MIC of IPR close to the breakpoint (MIC = 1 mg/L, n = 2; MIC = 2 mg/L, n = 3) yielded to a major error result, namely a positive result with the rapid IPR Pseudomonas NP test (resistance). By contrast, all IPR-resistant isolates (n = 42) were all correctly categorized.

CONCLUSIONS

The Rapid IPR Pseudomonas NP test is sensitive, specific, and easy to perform and interpret. Therefore, it is suitable for implementation in routine clinical laboratories.

Adaptations to cationic biocide exposure differentially influence virulence factors and pathogenicity in Pseudomonas aeruginosa

Cationic biocides (CBs), which include quaternary ammonium compounds (QACs), are employed to mitigate the spread of infectious bacteria, but resistance to such surface disinfectants is rising. CB exposure can have profound phenotypic implications that extend beyond allowing microorganisms to persist on surfaces. Pseudomonas aeruginosa is a deadly bacterial pathogen that is intrinsically tolerant to a wide variety of antimicrobials and is commonly spread in healthcare settings. In this study, we pursued resistance selection assays to the QAC benzalkonium chloride and quaternary phosphonium compound P6P-10,10 to assess the phenotypic effects of CB exposure in P. aeruginosa PAO1 and four genetically diverse, drug-resistant clinical isolates. In particular, we sought to examine how CB exposure affects defensive strategies and the virulence-associated "offensive" strategies in P. aeruginosa. We demonstrated that development of resistance to BAC is associated with increased production of virulence-associated pigments and alginate as well as pellicle formation. In an in vivo infection model, CB-resistant PAO1 exhibited a decreased level of virulence compared to wild type, potentially due to an observed fitness cost in these strains. Taken together, these results illustrate the significant consequence CB resistance exerts on the virulence-associated phenotypes of P. aeruginosa.

Leveraging bacteria-inspired nanomaterials for targeted controlling biofilm and virulence properties of Pseudomonas aeruginosa

Pseudomonas aeruginosa is an opportunistic pathogen designated as a high-priority pathogen because of its role in major healthcare-associated and nosocomial infections. Biofilm production by these bacteria is one of the adaptive resistance mechanisms to traditional antibiotics, making treatment challenging, especially for immunocompromised patients. P. aeruginosa also produces a variety of virulence factors, which aid in invasion, adhesion, persistence, and immune system protection. Recent advances in nanotechnology-based therapy, notably the application of bioinspired metal and metal-oxide nanomaterials, have been seen as a viable way to control P. aeruginosa biofilm and virulence. Because of its ease of growth and culture, synthesizing metal and metal-oxide nanomaterials using bacterial species has become one of the most environmentally benign green synthesis options. The application of bacterial-inspired nanomaterials is particularly successful for targeted control of P. aeruginosa infection due to interactions with cell membrane components and transport systems. This paper delves into and provides a complete overview of the application of bacterial-inspired metal and metal-oxide nanomaterials to treat P. aeruginosa infection by targeting biofilm and virulence characteristics. The review focused on synthesizing and applying gold, silver, copper, iron, magnetite, and zinc oxide nanomaterials to mitigate P. aeruginosa biofilm and virulence. The underlying mechanism of these metal and metal-oxide nanoparticles in relation to biofilm and virulence features has also been thoroughly discussed. The current review introduces novel approaches to treating and controlling drug-resistant P. aeruginosa using bacterial-inspired nanomaterials as a targeted therapeutic strategy.

CzcR-dependent reduction of catalase gene expression and induction of catalase activity in Pseudomonas aeruginosa during zinc excess

BACKGROUND

Pseudomonas aeruginosa is able to survive, grow, and cause severe infections at different sites throughout the human body owing to its ability to sense diverse signals and precisely modulate target gene expression using its abundant signaling systems. Release of zinc (Zn) and hydrogen peroxide (H2O2) within the phagocyte are two major host strategies to defend against bacterial infections. It was previously shown that the response regulator CzcR controls global gene expression including catalase genes during Zn excess, but regulatory mechanisms of catalase gene expression and the role of CzcR in H2O2 tolerance remain unclear.

RESULTS

In the study, comparative transcriptome analysis comprehensively described the CzcR-dependent and -independent gene regulatory pattern in P. aeruginosa during Zn excess, which revealed the counteractive co-regulation of two key H2O2-detoxifying catalase genes katA and katB through CzcR-dependent and -independent pathways in response to Zn excess. Protein-DNA interaction assay demonstrated that CzcR negatively regulates the expression of catalase genes katA and katB by directly binding to their promoters. While interestingly, we further showed that CzcR positively regulates H2O2 tolerance by inducing the catalase activity during Zn excess.

CONCLUSION

This study reported the opposite functions of CzcR in negatively regulating the expression of catalase genes katA and katB but in positively regulating the activity of catalase and H2O2 tolerance during Zn excess in P. aeruginosa.

Multidrug resistance in Pseudomonas aeruginosa: genetic control mechanisms and therapeutic advances

Pseudomonas aeruginosa is a significant opportunistic pathogen, and its complex mechanisms of antibiotic resistance pose a challenge to modern medicine. This literature review explores the advancements made from 1979 to 2024 in understanding the regulatory networks of antibiotic resistance genes in Pseudomonas aeruginosa, with a particular focus on the molecular underpinnings of these resistance mechanisms. The review highlights four main pathways involved in drug resistance: reducing outer membrane permeability, enhancing active efflux systems, producing antibiotic-inactivating enzymes, and forming biofilms. These pathways are intricately regulated by a combination of genetic regulation, transcriptional regulators, two-component signal transduction, DNA methylation, and small RNA molecules. Through an in-depth analysis and synthesis of existing literature, we identify key regulatory elements mexT, ampR, and argR as potential targets for novel antimicrobial strategies. A profound understanding of the core control nodes of drug resistance offers a new perspective for therapeutic intervention, suggesting that modulating these elements could potentially reverse resistance and restore bacterial susceptibility to antibiotics. The review looks forward to future research directions, proposing the use of gene editing and systems biology to further understand resistance mechanisms and to develop effective antimicrobial strategies against Pseudomonas aeruginosa. This review is expected to provide innovative solutions to the problem of drug resistance in infectious diseases.

Polymicrobial interactions influence Mycobacterium abscessus co-existence and biofilm forming capabilities

The lungs of patients with cystic fibrosis (CF) are vulnerable to persistent polymicrobial colonization by bacterial pathogens including Pseudomonas aeruginosa, Staphylococcus aureus, and the non-tuberculous mycobacterium (NTM) Mycobacterium abscessus. The polymicrobial milieu within the CF lung impacts individual species fitness, influences biofilm-forming capabilities, pathogenicity, production of virulence factors and even antimicrobial responses, all potentially compromising therapeutic success. Interaction studies among these CF pathogens are very limited, especially studies on the influences of P. aeruginosa and S. aureus on M. abscessus co-existence and virulence. Based on the little known thus far about coinfection of these pathogens, we hypothesize that the co-existence of P. aeruginosa and S. aureus alters M. abscessus virulence and phenotypic characteristics. We evaluated the direct (co-culture) and indirect (using supernatant) effects of P. aeruginosa and S. aureus on M. abscessus growth rate, biofilm formation, macrophage internalization and glycopeptidolipids (GPL) expression. Our observations indicate that P. aeruginosa and S. aureus exert a competitive behavior toward M. abscessus during direct contact or indirect interaction in-vitro, probably as is the case of polymicrobial infections in the lungs of patients with CF. This is the first report that demonstrates S. aureus inhibitory effects on M. abscessus growth and biofilm forming capabilities. Collectively, co-culture studies enhance our understanding of polymicrobial interactions during coinfection and can guide to establish better management of coinfections and treatment strategies for M. abscessus.

Computational approach towards repurposing of FDA approved drug molecules: strategy to combat antibiotic resistance conferred by Pseudomonas aeruginosa

Antimicrobial resistance is recognized as a major worldwide public health dilemma in the current century. Pseudomonas aeruginosa, a Gram-negative opportunistic pathogen, causes nosocomial infections like respiratory tract infections, urinary tract infections, dermatitis, and cystic fibrosis. It manifests antibiotic resistance via intrinsic, acquired, and adaptive pathways, where efflux pumps function in the extrusion of antibiotics from the cell. MexB protein, part of the tripartite efflux pumps MexAB-OprM present in P.aeruginosa, expels the penems and β-lactam antibiotics, thereby enhancing Pseudomonas resistance. The current study was intended to screen around 1602 clinically approved drugs to understand their ability to inhibit the MexB protein. Amongst them, the top 5 drug molecules were selected based on the binding energies for analyzing their physio-chemical and toxicity properties. Lomitapide was found to have the maximum negative binding energy followed by Nilotinib, whereas Nilotinib's number of hydrogen bonds was higher than that of Lomitapide. ADMET study revealed that all 5 drug molecules had limited solubility. Also, Lomitapide and Venetoclax showed low bioavailability scores, while Nilotinib, Eltrombopag, and Conivaptan demonstrated higher potential for therapeutic levels. A molecular dynamic simulation study of the 5 drugs against MexB was carried out for 200 nanoseconds. The RMSD, RMSF, Hydrogen bond formation, Radius of gyration, SASA, PCA, DCCM, DSSP and MM-PBSA binding energy calculation along with demonstrated high stability of the MexB-Nilotinib complex with lesser distortions. Our study concludes, that Nilotinib is a potential inhibitor and can be developed as a therapeutic agent against MexB protein for controlling P. aeruginosa infections.

Exploiting the Zebrafish Model for Sepsis Research: Insights into Pathophysiology and Therapeutic Potentials

Sepsis, a severe condition instigated by infections, continues to be a primary global cause of death, typified by systemic inflammation and advancing immune dysfunction. Comprehending the complex pathological processes that underlie sepsis is integral to the creation of efficacious treatments. Despite the inability of animal models to entirely reproduce the clinical intricacies related to sepsis, they are invaluable instruments for the exploration and development of therapeutic approaches. Within this context, the zebrafish model is particularly noteworthy due to its genetic tractability, transparency, and appropriateness for high-throughput screening of genetic mutants and therapeutic compounds. This scholarly review emphasizes the crucial role that the zebrafish disease model plays in enhancing our comprehension of sepsis, by exploring its applications in deciphering immune and inflammatory responses, evaluating the consequences of genetic alterations, and examining novel therapeutic agents. The Insights derived from zebrafish research not only augment our understanding of the underlying mechanisms of sepsis, but also possess considerable potential for the transference of these discoveries into clinical therapies, thus potentially transforming the approach to sepsis management. The objective of this scholarly article is to underscore the importance of zebrafish in the realm of biomedical research pertaining to sepsis, and to delineate forthcoming opportunities for utilizing this model in clinical applications.

Antibiotic resistance in Pseudomonas aeruginosa: mechanisms and emerging treatment

Pseudomonas aeruginosa, able to survive on the surfaces of medical devices, is a life-threatening pathogen that mainly leads to nosocomial infection especially in immunodeficient and cystic fibrosis (CF) patients. The antibiotic resistance in P. aeruginosa has become a world-concerning problem, which results in reduced and ineffective therapy efficacy. Besides intrinsic properties to decrease the intracellular content and activity of antibiotics, P. aeruginosa develops acquired resistance by gene mutation and acquisition, as well as adaptive resistance under specific situations. With in-depth research on drug resistance mechanisms and the development of biotechnology, innovative strategies have emerged and yielded benefits such as screening for new antibiotics based on artificial intelligence technology, utilizing drugs synergistically, optimizing administration, and developing biological therapy. This review summarizes the recent advances in the mechanisms of antibiotic resistance and emerging treatments for combating resistance, aiming to provide a reference for the development of therapy against drug-resistant P. aeruginosa.

High level non-carbapenemase carbapenem resistance by overlaying mutations of mexR, oprD, and ftsI in Pseudomonas aeruginosa

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a global threat, but the mechanism of non-carbapenemase carbapenem resistance is still unclear. In the current study, we investigated the contributions of point mutations in mexR, oprD, and ftsI to carbapenem resistance in P. aeruginosa during in vivo evolution studies with consecutive clinical isolates. Real-time qPCR and Electrophoretic Mobility Shift Assay demonstrated that MexR (Gln55Pro) mutation increased MexAB efflux pump genes expression by altering MexR's binding capacity, leading to a four- to eight-fold increase in meropenem MIC in the Pae d1 Green ∆mexR and PAO1∆mexR mutants. The OprD (Trp415*) truncation affected porin structure, and the constructed mutant Pae d1 Green oprD Trp415* increased meropenem MIC by 16-fold (from 0.25 to 4 µg/mL). The contribution of ftsI mutation to meropenem resistance was confirmed by clinical linkage analysis and was estimated to cause a two-fold increase in meropenem MIC by comparing the resistant clinical isolate with the Pae d1 Green oprD Trp415*∆mexR double mutant. The study found that the oprD Trp415* allele alone accounts for the imipenem MIC in clinical isolates, while the ∆mexR and ftsI Arg504Cys alleles do not contribute to imipenem resistance. In conclusion, we identified and explored the contributions of mexR, oprD, and ftsI mutations to high level non-carbapenemase carbapenem resistance in P. aeruginosa. These findings highlight the interplay of different mutations in causing non-carbapenemase carbapenem-resistance in P. aeruginosa.

IMPORTANCE

The emergence of carbapenem-resistant Pseudomonas aeruginosa (CRPA) poses a significant global health threat, complicating treatment options for infections caused by this pathogen. Understanding the mechanisms behind non-carbapenemase carbapenem resistance is critical for developing effective therapeutic strategies. This study provides crucial insights into how specific point mutations in key genes-mexR, oprD, and ftsI-contribute to carbapenem resistance, particularly the MexR (Gln55Pro) mutation's effect on efflux pump expression and the OprD (Trp415*) truncation's impact on porin structure. The findings elucidate the complex interplay of these mutations, highlighting their roles in conferring high-level resistance, and underscore the imperative for continued research to inform therapeutic strategies against CRPA infections.

Amphiphilic Janus Nanoparticles for Effective Treatment of Bacterial Pneumonia by Attenuating Inflammation and Targeted Bactericidal Capability

Introduction

Pseudomonas aeruginosa (P. aeruginosa)-induced pneumonia is marked by considerable infiltration of inflammatory cells and biofilm formation, which causes acute and transient lung inflammation and infection. Nevertheless, the discovery of alternative preventative and therapeutic methods is essential due to the high mortality rates in clinical settings and the resistance of P. aeruginosa infection to multiple medications.

Purpose

In this research, we constructed amphiphilic Janus nanoparticles (JNPs, denoted as SSK1@PDA/CaP@CIP), loaded with hydrophobic SSK1, a β-galactosidase (β-gal)-activated prodrug for reducing macrophages, and hydrophilic ciprofloxacin (CIP), a classic antibiotic for treating infection. SSK1@PDA/CaP@CIP was designed to effectively attenuate inflammation, eradicate biofilms, and combat planktonic P. aeruginosa.

Results

As expected, SSK1@PDA/CaP@CIP was able to target the infection site and demonstrated outstanding efficacy in treating P. aeruginosa strain PAO1-induced pneumonia by regulating macrophage infiltration to reduce inflammation and removing planktonic bacteria and biofilms to control infection. Additionally, the primary organs did not exhibit any discernible pathological changes following treatment with SSK1@PDA/CaP@CIP, which indicates superior biocompatibility throughout the treatment course.

Discussion

In conclusion, our investigation introduced a promising approach to the treatment of pneumonia associated with PAO1.

Combining Aloin with TIENAM ameliorates cecal ligation and puncture-induced sepsis in mice by attenuating inflammation and modulating abdominal cavity microbiota

Despite the high mortality rate, sepsis lacks specific and effective treatment options. Conventional antibiotics, such as TIENAM (TIE; imipenem and cilastatin sodium for injection), face challenges owing to the emergence of bacterial resistance, which reduces their effectiveness and causes adverse effects. Addressing resistance and judicious drug use is crucial. Our research revealed that aloin (Alo) significantly boosts survival rates and reduces inflammation and bacterial load in mice with sepsis, demonstrating strong antimicrobial activity. Using a synergistic Alo + TIE regimen in a cecal ligation and puncture (CLP)-induced sepsis model, we observed a remarkable increase in survival rates from 10 % to 75 % within 72 h compared with the CLP group alone. This combination therapy also modulated inflammatory markers interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α, mitigated tissue damage, regulated immune cells by lowering NK, activated CD8+ and CD4+ T cells while increasing peritoneal macrophages, and decreased the bacterial load in the peritoneal cavity. We noted a significant shift in the abdominal cavity microbiota composition post-treatment, with a decrease in harmful bacteria, such as Lachnospiraceae_NK4A136_group, Klebsiella, Bacillus, and Escherichia, and an increase in beneficial bacteria, such as Lactobacillus and Mucispirillum. Our study emphasizes the efficacy of combining Alo with TIE to combat sepsis, and paves the way for further investigations and potential clinical applications aiming to overcome the limitations of TIE and enhance the therapeutic prospects of Alo.

Combining ulinastatin with TIENAM improves the outcome of sepsis induced by cecal ligation and puncture in mice by reducing inflammation and regulating immune responses

Despite the high mortality associated with sepsis, effective and targeted treatments remain scarce. The use of conventional antibiotics such as TIENAM (imipenem and cilastatin sodium for injection, TIE) is challenging because of the increasing bacterial resistance, which diminishes their efficacy and leads to adverse effects. Our previous studies demonstrated that ulinastatin (UTI) exerts a therapeutic impact on sepsis by reducing systemic inflammation and modulating immune responses. In this study, we examined the possibility of administering UTI and TIE after inducing sepsis in a mouse model using cecal ligation and puncture (CLP). We assessed the rates of survival, levels of inflammatory cytokines, the extent of tissue damage, populations of immune cells, microbiota in ascites, and important signaling pathways. The combination of UTI and TIE significantly improved survival rates and reduced inflammation and bacterial load in septic mice, indicating potent antimicrobial properties. Notably, the survival rates of UTI+TIE-treated mice increased from 10 % to 75 % within 168 h compared to those of mice that were subjected to CLP. The dual treatment successfully regulated the levels of inflammatory indicators (interleukin [IL]-6, IL-1β, and tumor necrosis factor [TNF]-α) and immune cell numbers by reducing B cells, natural killer cells, and TNFR2+ Treg cells and increasing CD8+ T cells. Additionally, the combination of UTI and TIE alleviated tissue damage, reduced bacterial load in the peritoneal cavity, and suppressed the NF-κB signaling pathway. Our findings indicate that UTI and TIE combination therapy can significantly enhance sepsis outcomes by reducing inflammation and boosting the immune system. The results offer a promising therapeutic approach for future sepsis treatment.

Presence of Pseudomonas aeruginosa in feces exacerbate leaky gut in mice with low dose dextran sulfate solution, impacts of specific bacteria

The impact of Pseudomonas aeruginosa (PA) was explored in a mouse model with non-diarrheal gut permeability defect using 1.5% dextran sulfate solution (DSS) plus antibiotics (ATB) with or without orally administered PA. As such, ATB+DSS+PA mice induced more severe intestinal injury as indicated by stool consistency and leaky gut (FITC-dextran assay, bacteremia, and endotoxemia) with an increase in serum cytokines, liver enzyme, and hepatocyte apoptosis when compared with ATB+DSS mice. There was no abnormality by these parameters in the non-DSS group, including water alone (control), antibiotics alone (ATB+water), and antibiotics with PA (ATB+water+PA). Despite a similarly fecal microbiome patterns between ATB+DSS and ATB+DSS+PA groups, a higher abundance of Pseudomonas, Enterococci, and Escherichia-Shigella was detected in ATB+DSS+PA mice. Additionally, the additive pro-inflammation between pathogen molecules, using heat-killed P. aeruginosa preparations, and LPS against enterocytes (Caco2) and hepatocytes (HegG2), as indicated by supernatant IL-8 and expression of several genes (IL-8, NF-kB, and NOS2) are demonstrated. In conclusion, presence of P. aeruginosa in the gut exacerbated DSS-induced intestinal injury with spontaneous translocation of LPS and bacteria from the gut into the blood circulation (leaky gut) that induced more severe systemic inflammation. The presence of pathogenic bacteria, especially PA in stool of the healthy individuals might have some adverse effect. More studies are in needed.

Engineering Cyborg Pathogens through Intracellular Hydrogelation

Synthetic biology primarily focuses on two kinds of cell chassis: living cells and nonliving systems. Living cells are autoreplicating systems that have active metabolism. Nonliving systems, including artificial cells and nanoparticles, are nonreplicating systems typically lacking active metabolism. In recent work, Cyborg bacteria that are nonreplicating-but-metabolically active have been engineered through intracellular hydrogelation. Intracellular hydrogelation is conducted by infusing gel monomers and photoactivators into cells, followed by the activation of polymerization of the gel monomers inside the cells. However, the previous work investigated only Escherichia coli cells. Extending the Cyborg-Cell method to pathogenic bacteria could enable the exploitation of their pathogenic properties in biomedical applications. Here, we focus on different strains of Pseudomonas aeruginosa, Staphylococcus aureus, and Klebsiella pneumoniae. To synthesize the Cyborg pathogens, we first reveal the impact of different hydrogel concentrations on the metabolism, replication, and intracellular gelation of Cyborg pathogens. Next, we demonstrate that the Cyborg pathogens are taken up by macrophages in a similar magnitude as wild-type pathogens through confocal microscopy and real-time PCR. Finally, we show that the macrophage that takes up the Cyborg pathogen exhibits a similar phenotypic response to the wild-type pathogen. Our work generalizes the intracellular hydrogelation approach from lab strains of E. coli to bacterial pathogens. The new Cyborg pathogens could be applied in biomedical applications ranging from drug delivery to immunotherapy.

A systematic overview of strategies for photosensitizer and light delivery in antibacterial photodynamic therapy for lung infections

Antimicrobial photodynamic therapy (aPDT) emerges as a viable treatment strategy for infections resistant to conventional antibiotics. A complex interplay of factors, including intracellular photosensitizer (PS) accumulation, photochemical reaction type, and oxygen levels, determines the efficacy of aPDT. Recent progress includes the development of modified PSs with enhanced lipophilicity and target-specific strategies to improve bacterial cell wall penetration and targeting. Nanotechnology-based approaches, such as using nanomaterials for targeted PS delivery, have shown promise in enhancing aPDT efficacy. Advancements in light delivery methods for aPDT, such as transillumination of large lesions and local light delivery using fiber optic techniques, are also being explored to optimize treatment efficacy in clinical settings. The limited number of animal models and clinical trials specifically designed to assess the efficacy of aPDT for lung infections highlights the need for further research in this critical area. The potential prospects of aPDT for lung tissue infections originating from antibiotic-resistant bacterial infections are also discussed in this review.

How Nanoparticles Help in Combating Chronic Wound Biofilms Infection?

Chronic wound infection has become a global health problem, with bacterial biofilms, which are difficult to penetrate using traditional antibiotics, considered the primary cause of recurrent infection and delayed healing in chronic wounds. In recent years, the outstanding performance of nanomaterials in controlling biofilm infections has been widely acknowledged, and these materials are regarded as highly promising for chronic wound infection management. The formation and structure of chronic wound biofilms undergo complex dynamic changes. Therefore, a deep understanding of the underlying causes of repeated wound infections and the specific antibacterial mechanisms of nanomaterials at different stages of biofilm formation is crucial for effective "chronic wound infection management". This review first reveals the relationship between biofilms, wound chronicity, and recurrent infections. Secondly, it focuses on the four stages of chronic wound biofilm formation: (1) adhesion stage, (2) aggregation and promotion stage, (3) maturation stage, and (4) regeneration and dissemination stage. It also comprehensively summarizes the specific antibacterial mechanisms of nanomaterials. This study analyzes essential factors affecting the control of chronic wound biofilms by nanoparticles from various perspectives, such as the material itself, the local wound environment, and the systemic host response. Finally, the limitations and potential future trends in current research are discussed. In summary, nanoparticles represent a promising strategy for combating chronic wound biofilm infections, and this review provides new insights for alternative adjuvant therapies in managing bacterial biofilm infections in chronic wounds.

Loop-Mediated Isothermal Amplification Coupled with Reverse Line Blot Hybridization for the Detection of Pseudomonas aeruginosa

Pseudomonas aeruginosa is a pathogen of critical priority importance according to the WHO. Due to its multi-resistance and expression of various virulence factors, it is the causal agent of severe healthcare-acquired infections (HAIs). Effective strategies to control infections caused by P. aeruginosa must include early and specific detection of the pathogen for early and timely antibiotic prescription. The need to develop a specific and reproducible diagnostic technique is urgent, which must often be more sensitive and faster than current clinical diagnostic methods. In this study, we implement and standardize the loop-mediated isothermal amplification (LAMP) technique, coupled with the reverse line blot hybridization (RLBH) technique for the detection of P. aeruginosa. A set of primers and probes was designed to amplify a specific region of the P. aeruginosa 16s rRNA gene. The sensitivity of the LAMP-RLBH method was 3 × 10-4 ng/μL, 1000 times more sensitive than the PCR and LAMP technique (this work), with a sensitivity of 3 × 10-3 ng/μL. The LAMP-RLBH and LAMP techniques showed specific amplification and no cross-reaction with members of the ESKAPE group and other Pseudomonas species. The present investigation provides a technique that can be easily performed in less time, achieving a faster and more reliable alternative compared to traditional microbial diagnostic methods for the detection of P. aeruginosa.

Clinical characteristics and prognosis analysis of pseudomonas aeruginosa bloodstream infection in adults: a retrospective study

Pseudomonas aeruginosa bloodstream infections (PA BSIs) in adults, especially those complicated by sepsis, are associated with high rates of morbidity and mortality. Early identification of risk factors for both mortality and sepsis-induced coagulopathy (SIC) is critical to optimizing patient management and improving outcomes. We conducted a retrospective analysis of 118 adult patients diagnosed with PA BSIs at the Affiliated Hospital of Xuzhou Medical University from January 2022 to February 2024. Univariate analysis was employed to identify significant clinical factors, followed by multivariate stepwise logistic regression to determine independent predictors of mortality and SIC. Based on these findings, nomogram models were constructed and evaluated using the area under the receiver operating characteristic curve (AUC), Bootstrap resampling, and calibration plots to assess model performance. Empiric sensitive antibiotic therapy (ESAT) (OR = 0.039, P < 0.001), coronary artery disease (CAD) (OR = 10.315, P = 0.010), and invasive mechanical ventilation (OR = 3.926, P = 0.020) emerged as significant predictors of mortality. In contrast, elevated C-reactive protein (CRP) (OR = 1.011, P = 0.003), procalcitonin (PCT) (OR = 1.030, P = 0.005), and lower hemoglobin levels (OR = 0.963, P = 0.004) were independently associated with SIC. The AUC of mortality prediction model is 0.908, while the SIC prediction model yielded an AUC of 0.817. The predictive models developed in this study demonstrate early identification of mortality rates and SIC risk in PA BSI patients, which may have the potential to guide timely therapeutic interventions and improve clinical outcomes in this high-risk population.

Complete genome sequences of three Pseudomonas aeruginosa jumbo bacteriophages discovered in Kenya

The genomes of three Pseudomonas aeruginosa Phikzvirus bacteriophages isolated in Kenya are described. The genomes of phages vB_PaePAO1-KEN19, vB_Pae3705-KEN49, and vB_Pae10145-KEN51, respectively, had lengths of 278,921, 280,231, and 280,173 bp, with 36.93%, 36.84%, and 36.86% GC content, containing 419, 417, and 417 coding sequences (including seven tRNAs in each genome).