A comprehensive status update on modification of foley catheter to combat catheter-associated urinary tract infections and microbial biofilms.

Present-day healthcare employs several types of invasive devices, including urinary catheters, to improve medical wellness, the clinical outcome of disease, and the quality of patient life. Among urinary catheters, the Foley catheter is most commonly used in patients for bladder drainage and collection of urine. Although such devices are very useful for patients who cannot empty their bladder for various reasons, they also expose patients to catheter-associated urinary tract infections (CAUTIs). Catheter provides an ideal surface for bacterial colonization and biofilm formation, resulting in persistent bacterial infection and severe complications. Hence, rigorous efforts have been made to develop catheters that harbour antimicrobial and anti-fouling properties to resist colonization by bacterial pathogens. In this regard, catheter modification by surface functionalization, impregnation, blending, or coating with antibiotics, bioactive compounds, and nanoformulations have proved to be effective in controlling biofilm formation. This review attempts to illustrate the complications associated with indwelling Foley catheters, primarily focussing on challenges in fighting CAUTI, catheter colonization, and biofilm formation. In this review, we also collate scientific literature on catheter modification using antibiotics, plant bioactive components, bacteriophages, nanoparticles, and studies demonstrating their efficacy through in vitro and in vivo testing.

Lumpy skin disease: Insights into current status and geographical expansion of a transboundary viral disease.

Lumpy skin disease (LSD) is an emerging transboundary viral disease of livestock animals which was first reported in 1929 in Zambia. Although LSD is a neglected disease of economic importance, it extends a direct impact on the international trade and economy in livestock-dependent countries. Lumpy skin disease virus (LSDV) has been endemic in African countries, where several outbreaks have been reported previously. However, the virus has spread rapidly across the Middle East in the past two decades, reaching Russia and, recently, the Asian subcontinent. With unprecedented cluster outbreaks being reported across Asian countries like India, China, Nepal, Bangladesh, and Pakistan, LSDV is certainly undergoing an epidemiological shift and expanding its geographical footprint worldwide. Due to high mortality among livestock animals, the recent LSD outbreaks have gained attention from global regulatory authorities and raised serious concerns among epidemiologists and veterinary researchers. Despite networked global surveillance of the disease, recurrent LSD cases pose a threat to the livestock industry. Hence, this review provides recent insights into the LSDV biology by augmenting the latest literature associated with its pathogenesis, transmission, current intervention strategies, and economic implications. The review critically examines the changing epidemiological footprint of LSDV globally, especially in relation to developing countries of the Asian subcontinent. We also speculate the possible reasons contributing to the ongoing LSD outbreaks, including illegal animal trade, climate change, genetic recombination events between wild-type and vaccine strains, reversion of vaccine strains to virulent phenotype, and deficiencies in active monitoring during the COVID-19 pandemic.

Repurposing albendazole as a potent inhibitor of quorum sensing-regulated virulence factors in Pseudomonas aeruginosa: Novel prospects of a classical drug.

Pseudomonas aeruginosa has emerged as a critical superbug that poses a serious threat to public health. Owing to its virulence and multidrug resistance profiles, the pathogen demands immediate attention for devising alternate intervention strategies. In an attempt to repurpose drugs against P. aeruginosa, this preclinical study was aimed at investigating the antivirulence prospects of albendazole (AbZ), an FDA-approved anti-helminthic drug, recently predicted to disrupt quorum sensing (QS) in Chromobacterium violaceum. AbZ was scrutinized for its quorum quenching (QQ) prospects, effect on bacterial virulence, different motility phenotypes, and biofilm formation in vitro. Additionally, in silico analysis was employed to predict the molecular interactions between AbZ and QS receptors. At sub-inhibitory levels, AbZ demonstrated anti-QS activity and significantly abrogated AHL biosynthesis in P. aeruginosa. Moreover, AbZ significantly downregulated the transcript levels of QS- (lasI/lasR, rhlI/rhlR, and pqsA/pqsR) and QS-dependent virulence (aprA, lasA, lasB, plcH, and toxA) genes in P. aeruginosa. This coincided with reduced hemolysin, alginate, pyocyanin, rhamnolipids, total protease, and elastase production, thereby lowering phenotypic virulence. Molecular docking with AbZ further revealed strong associations and high binding energies with LasR (-8.8 kcal/mol), RhlR (-6.5 kcal/mol), and PqsR (-6.3 kcal/mol) receptors. AbZ also impeded bacterial motility and abolished EPS production, severely compromising pseudomonal biofilm formation. For the first time, AbZ was shown to interfere with QS circuitry and consequently disarming pseudomonal virulence. Hence, AbZ can be exploited for its antivirulence properties against P. aeruginosa.

Anti-virulence prospects of Metformin against Pseudomonas aeruginosa: A new dimension to a multifaceted drug.

Metformin (MeT) is an FDA-approved drug with a myriad of health benefits. Besides being used as an anti-diabetic drug, MeT is also effective against various cancers, liver-, cardiovascular-, and renal diseases. This study was undertaken to examine its unique potential as an anti-virulence drug against an opportunistic bacterial pathogen, Pseudomonas aeruginosa. Due to the menace of multidrug resistance in pathogenic microorganisms, many novel or repurposed drugs with anti-virulence prospects are emerging as next-generation therapies with the aim to overshadow the application of existing antimicrobial regimens. The quorum sensing (QS) mechanisms of P. aeruginosa are an attractive drug target for attenuating bacterial virulence. In this context, the anti-QS potential of MeT was scrutinized using biosensor assays. MeT was comprehensively evaluated for its effects on different motility phenotypes, virulence factor production (phenotypic and genotypic expression) along with biofilm development in P. aeruginosa in vitro. At sub-lethal concentrations, MeT displayed prolific quorum quenching (QQ) ability and remarkably inhibited AHL biosynthesis in P. aeruginosa. Moreover, MeT (1/8 MIC) effectively downregulated the expression levels of various QS- and virulence genes in P. aeruginosa, which coincided with a notable reduction in the levels of alginate, hemolysin, pyocyanin, pyochelin, elastase, and protease production. In silico analysis through molecular docking also predicted strong associations between MeT and QS receptors of P. aeruginosa. MeT also compromised the motility phenotypes and successfully abrogated biofilm formation by inhibiting EPS production in P. aeruginosa. Hence, MeT may be repurposed as an anti-virulence drug against P. aeruginosa in clinical settings.

Revisiting the virulence hallmarks of Pseudomonas aeruginosa: a chronicle through the perspective of quorum sensing.

Pseudomonas aeruginosa is an opportunistic pathogen and the leading cause of mortality among immunocompromised patients in clinical setups. The hallmarks of virulence in P. aeruginosa encompass six biologically competent attributes that cumulatively drive disease progression in a multistep manner. These multifaceted hallmarks lay the principal foundation for rationalizing the complexities of pseudomonal infections. They include factors for host colonization and bacterial motility, biofilm formation, production of destructive enzymes, toxic secondary metabolites, iron-chelating siderophores and toxins. This arsenal of virulence hallmarks is fostered and stringently regulated by the bacterial signalling system called quorum sensing (QS). The central regulatory functions of QS in controlling the timely expression of these virulence hallmarks for adaptation and survival drive the disease outcome. This review describes the intricate mechanisms of QS in P. aeruginosa and its role in shaping bacterial responses, boosting bacterial fitness. We summarize the virulence hallmarks of P. aeruginosa, relating them with the QS circuitry in clinical infections. We also examine the role of QS in the development of drug resistance and propose a novel antivirulence therapy to combat P. aeruginosa infections. This can prove to be a next-generation therapy that may eventually become refractory to the use of conventional antimicrobial treatments.

Insights into the monkeypox virus: Making of another pandemic within the pandemic?

Just when the world started to adapt to the 'new normal' amid the coronavirus disease 19 (COVID-19) pandemic, the world is witnessing the wrath of another viral disease, the monkeypox virus (MPXV). The virus is endemic to African countries, where several outbreaks have been reported in the past. However, the present cases have been reported in non-endemic countries worldwide. Although MPX is considered to be a self-limiting disease, recent reports on its incidence have proved otherwise. The 2022 multi-country MPX outbreak has drawn the attention of global surveillance organizations and epidemiologists to trace its origin; however, there are existing gaps regarding the animal reservoirs, biological implications, and management of MPX. In view of the recent events, the World Health Organization (WHO) has also declared the ongoing MPX outbreak a global health emergency. Hence, the geographically expanding MPXV poses a significant threat to human health and public safety. In this review, the latest insights into the biology of MPXV have been provided by discussing its biological implications on human health, changing epidemiological footprint, and presently available intervention strategies. This review also sheds light on the existing lacunas and possible reasons that may have been responsible for the ongoing MPX outbreak.

Exploring the therapeutic potential of staphylococcal phage formulations: Current challenges and applications in phage therapy.

Unconstrained consumption of antibiotics throughout the expanse of the 21st century has resulted in increased antimicrobial resistance (AMR) among bacterial pathogens, a transpiring predicament affecting the public healthcare sector. The upsurge of multidrug-resistant pathogens, including Staphylococcus aureus, synchronously with the breakdown of the conventional antibiotic pipeline has led to the exploration of alternate strategies. Phage therapy applications have thus gained immense prominence among the scientific community to conquer this notorious pathogen associated with wide-ranging clinical manifestations, especially in immunosuppressed individuals. In this direction, a plethora of phage formulations like topical solutions, medicated dressings impregnated with phages, liposomal entrapments, etc., have been considered as an effective and upcoming strategy. Owing to the synergistic effect of phages with other antibacterial agents, they can be easily exploited for biomedical application. This review primarily focuses on the therapeutic implications of S. aureus phages in the biotechnological and medical arena. Through this review article, we have also discussed the current status and the incurring challenges in phage therapy.

Guaiacol augments quorum quenching potential of ciprofloxacin against Pseudomonas aeruginosa.

AIM: The present study aims to investigate the antimicrobial as well as antivirulence potential and the principle mechanism of action of guaiacol against Pseudomonas aeruginosa. METHODS AND RESULTS: Quorum sensing inhibition and membrane disruption studies were performed to check the effect of guaiacol on the virulence of P. aeruginosa. Production of various virulence factors and biofilm formation was studied at a sub-MIC concentration of guaiacol alone (1/8 MIC) and in combination with ciprofloxacin (1/2 FIC). Guaiacol exhibited synergistic interactions with ciprofloxacin and further reduced the production of all virulence factors and biofilm formation. Using crystal violet (CV) assay and quantification of exopolysaccharide, we observed weak biofilm formation, together with reduced motilities at sub-MIC, which was further visualized by confocal laser microscopy and Field Emission Scanning Electron Microscopy. The antibacterial activity of guaiacol against P. aeruginosa upon 2 × MIC exposure coincided with enhanced membrane permeability leading to disruption and release of cellular material as quantified by CV uptake assay and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The results demonstrated that sub-MICs of guaiacol in combination with ciprofloxacin can act as a potent alternate compound for attenuation of quorum sensing in P. aeruginosa. CONCLUSION: The study reports that guaiacol in combination with ciprofloxacin at 1/2 FIC significantly compromised the bacterial growth and motilities alongside inducing quorum quenching potential. This was accompanied by inhibition of biofilm which subsequently decreased EPS production at sub-MIC concentration. Furthermore, guaiacol in combination displayed a severe detrimental effect on bacterial membrane disruption, thereby enhancing cellular material release. NOVELTY IMPACT STATEMENT: For the first time, the potential of guaiacol in combination with ciprofloxacin in attenuation of virulence factors, and biofilm formation in Pseudomonas aeruginosa was described. Results corroborate how plant bioactive in synergism with antibiotics can act as an alternate treatment regime to tackle the menace of drug resistance.

Self-targeting spacers in CRISPR-array: Accidental occurrence or evolutionarily conserved phenomenon.

In recent years, a tremendous amount of inquisitiveness among scientists in the clustered regularly interspaced short palindrome repeats (CRISPR)-CRISPR-associated proteins (Cas) has led to many studies to delineate their exact role in prokaryotes. CRISPR-Cas is an adaptive immune system that protects prokaryotes from phages and mobile genetic elements. It incorporates small DNA fragment of the invader in the CRISPR-array and protects the host from future invasion by them. In a few instances, the CRISPR-array also incorporates self-targeting spacers, most likely by accident or leaky incorporation. A significant number of spacers are found to match with the host genes across the species; however, self-targeting spacers have not been investigated in detail in most of the organisms. The presence of self-targeting spacers in the CRISPR-array led to speculation that the CRISPR-Cas system has a lot more to offer than just being the conventional adaptive immune system. It has been implicated in gene regulation and autoimmunity more or less equally. In this review, an attempt has been made to understand self-targeting spacers in the context of gene regulation, autoimmunity, and its avoidance strategies.

Molecular Mechanisms and Applications of N-Acyl Homoserine Lactone-Mediated Quorum Sensing in Bacteria.

Microbial biodiversity includes biotic and abiotic components that support all life forms by adapting to environmental conditions. Climate change, pollution, human activity, and natural calamities affect microbial biodiversity. Microbes have diverse growth conditions, physiology, and metabolism. Bacteria use signaling systems such as quorum sensing (QS) to regulate cellular interactions via small chemical signaling molecules which also help with adaptation under undesirable survival conditions. Proteobacteria use acyl-homoserine lactone (AHL) molecules as autoinducers to sense population density and modulate gene expression. The LuxI-type enzymes synthesize AHL molecules, while the LuxR-type proteins (AHL transcriptional regulators) bind to AHLs to regulate QS-dependent gene expression. Diverse AHLs have been identified, and the diversity extends to AHL synthases and AHL receptors. This review comprehensively explains the molecular diversity of AHL signaling components of Pseudomonas aeruginosa, Chromobacterium violaceum, Agrobacterium tumefaciens, and Escherichia coli. The regulatory mechanism of AHL signaling is also highlighted in this review, which adds to the current understanding of AHL signaling in Gram-negative bacteria. We summarize molecular diversity among well-studied QS systems and recent advances in the role of QS proteins in bacterial cellular signaling pathways. This review describes AHL-dependent QS details in bacteria that can be employed to understand their features, improve environmental adaptation, and develop broad biomolecule-based biotechnological applications.

Design, synthesis, molecular docking, anti-quorum sensing, and anti-biofilm activity of pyochelin-zingerone conjugate.

In this article, we report the chemical synthesis of pyochelin-zingerone conjugate via a hydrolysable ester linkage for drug delivery as a "Trojan Horse Strategy." It is a new therapeutic approach to combat microbial infection and to address the issue of multi drug resistance in Gram-negative, nosocomial pathogen Pseudomonas aeruginosa. Pyochelin (Pch) is a catecholate type of phenolate siderophore produced and utilized by the pathogen P. aeruginosa to assimilate iron when colonizing the vertebrate host. Zingerone, is active component present in ginger, a dietary herb known for its anti-virulent approach against P. aeruginosa. In the present study, zingerone was exploited to act as a good substitute for existing antibiotics, known to have developed resistance by most pathogens. Encouraging results were obtained by docking analysis of pyochelin-zingerone conjugate with FptA, the outer membrane receptor of pyochelin. Conjugate also showed anti-quorum sensing activity and also inhibited swimming, swarming, and twitching motilities as well as biofilm formation in vitro.

Early cytokine response to lethal challenge of Klebsiella pneumoniae averted the prognosis of pneumonia in FyuA immunized mice.

Klebsiella pneumoniae, a multi drug resistant nosocomial pathogen is associated with pneumonia and immunization gives a hope to fight its infections. A possible vaccine candidate is the conserved protein, yersiniabactin receptor FyuA. Its expression along with the siderophore yersiniabactin increases in bacteria under iron starving conditions prevailing in lungs. In this study, the potential of recombinant FyuA of K. pneumoniae has been evaluated against lung infection in BALB/c mice. Immunization generated both humoral and cell mediated response which conferred protection against the lethal dose of bacteria. Bacterial burden in lungs reduced by 6 log10 CFU/ml after 2nd day post infection as compared to control. Similarly, the levels of pro-inflammatory cytokines IL-17, TNF-α and IL-1ß were also reduced significantly; reduced tissue damage was evident from histopathology of lungs in immunized mice. These results indicate the protective role of FyuA which can be a potential vaccine candidate.

A potent enzybiotic against methicillin-resistant Staphylococcus aureus.

Staphylococcus aureus is one of the most dreadful infectious agents, responsible for high mortality and morbidity in both humans and animals. The increased prevalence of multidrug-resistant (MDR) Staphylococcus aureus strains has limited the number of available treatment options, which calls for the development of alternative and effective modalities against MDR S. aureus. Endolysins are bacteriophage-derived antibacterials, which attack essential conserved elements of peptidoglycan that are vital for bacterial survival, making them promising alternatives or complements to existing antibiotics for tackling such infections. For developing endolysin lysin-methicillin-resistant-5 (LysMR-5) as an effective antimicrobial agent, we evaluated its physical and chemical characteristics, and its intrinsic antibacterial activity against staphylococcal strains, including methicillin-resistant Staphylococcus aureus (MRSA). In this study, we cloned, expressed, and purified LysMR-5 from S. aureus phage MR-5. In silico analysis revealed that LysMR-5 harbors two catalytic and one cell wall-binding domain. Biochemical characterization and LC-MS analysis showed that both catalytic domains were active and had no dependence on divalent ions for their action, Zn2+ exerted a negative effect. The optimal lytic activity of the endolysin was at 37 °C/pH 7.0 and in the presence of ≥ 300 mM concentration of NaCl. Circular dichroism (CD) demonstrated a loss in secondary structure with an increase in temperature confirming the thermosensitive nature of endolysin. Antibacterial assays revealed that LysMR-5 was active against diverse clinical isolates of staphylococci. It showed high lytic efficacy against S. aureus ATCC 43300, as an endolysin concentration as low as 15 µg/ml was sufficient to achieve maximum lytic activity within 30 min and it was further confirmed by scanning electron microscopy. Our results indicate that rapid and strong bactericidal activity of LysMR-5 makes it a valuable candidate for eradicating multidrug-resistant S. aureus.

Exploring Endolysin-Loaded Alginate-Chitosan Nanoparticles as Future Remedy for Staphylococcal Infections.

Endolysins are a novel class of antibacterials with proven efficacy in combating various bacterial infections, in vitro and in vivo. LysMR-5, an endolysin derived from phage MR-5, demonstrated high lytic activity in our laboratory against multidrug-resistant S. aureus (MRSA) and S. epidermidis strains. However, endolysin and proteins in general are associated with instability and short in vivo half-life, consequently limiting their usage as pharmaceutical preparation to treat bacterial infections. Nanoencapsulation of endolysins could help to achieve better therapeutic outcome, by protecting the proteins from degradation, providing sustained release, thus could increase their stability, shelf life, and therapeutic efficacy. Hence, in this study, the feasibility of alginate-chitosan nanoparticles (Alg-Chi NPs) to serve as drug delivery platform for LysMR-5 was evaluated. LysMR-5-loaded nanoparticles were prepared by calcium ion-induced pre-gelation of alginate core and its complexation with chitosan. The formation of nanoparticles was confirmed on the basis of DLS, zeta potential, and electron microscopy imaging. The LysMR-5-loaded nanoparticles presented a hydrodynamic diameter of 276.5 ± 42, a PDI of 0.342 ± 0.02, a zeta potential - 25 mV, and an entrapment efficiency of 62 ± 3.1%. The potential ionic interaction between alginate, chitosan, and LysMR-5 was investigated by FT-IR and SEM-EDX analysis. Using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), nano-sized particles with characteristic morphology were seen. Different antibacterial assays and SDS-PAGE analysis showed no change in endolysin's structural integrity and bioactivity after entrapment. A direct antibacterial effect of blank Alg-Chi Nps, showing enhanced bactericidal activity upon LysMR-5 loading, was observed against S. aureus. At physiological pH (7.2), the release profile of LysMR-5 from Alg-Chi NPs showed a biphasic release and followed a non-Fickian release mechanism. The biocompatible nature as revealed by cytocompatibility and hemocompatibility studies endorsed their use as drug delivery system for in vivo studies. Collectively, these results demonstrate the potential of Alg-Chi NPs as nano-delivery vehicle for endolysin LysMR-5 and other therapeutic proteins for their use in various biomedical applications.

Parallels among natural and synthetically modified quorum-quenching strategies as convoy to future therapy.

Quorum sensing (QS) refers to chemical signalling between micro-organisms and defines a social concord among them. Once a threshold of signal is accumulated, certain virulent traits are regulated within bacteria in response to the surrounding environment. These virulence traits are known to contribute in the pathogenicity of bacterial diseases. To prevent the activation of virulence factors, QS is inhibited in different ways through a strategy known as quorum quenching. Various types of quorum-quenching strategies have already been used and characterized, as discussed in this review. The phenomenon of quorum quenching has long been considered as an alternative therapy to circumvent the ill-effects of the overuse of antibiotics. Considering the need to compare and evaluate various strategies, selected quorum-quenching paradigms are detailed along with their pros and cons in this review. A rationale has been drawn between naturally evolved quorum-quenching strategies and synthetically modified approaches adopted to abrogate QS.

Effective Topical Delivery of H-AgNPs for Eradication of Klebsiella pneumoniae-Induced Burn Wound Infection.

The aim of the present study was to explore the therapeutic efficacy of microemulsion-based delivery of histidine-capped silver nanoparticles in eradicating Klebsiella pneumoniae-induced burn wound infection. The developed microemulsion was characterized on the basis of differential light scattering, phase separation, refractive index, and specific conductance. Emulgel was prepared and characterized on the basis of thixotropy, texture, differential scanning calorimetry, and release kinetics. Emulgel was further evaluated in skin irritation and in vivo studies, namely full-thickness K. pneumoniae-induced burn wound infection treatment via topical route. Efficacy of treatment was evaluated in terms of bacterial load, histopathology, wound contraction, and other infection markers. The developed emulgel provided significant in vivo antibacterial activity of histidine-capped silver nanoparticle preparations via topical route and resulted in reduction in bacterial load, wound contraction, and enhanced skin healing as well as decrement of inflammatory markers such as malondialdehyde, myeloperoxidase, and reactive nitrogen intermediate compared to untreated animals. The present study encourages the further employment of histidine-capped silver nanoparticles along with microemulsion-based drug delivery system in combating antibiotic-resistant topical infections.

Chryseobacterium glaciei sp. nov., isolated from the surface of a glacier in the Indian trans-Himalayas.

A novel bacterial strain, IHBB 10212T, of the genus Chryseobacterium was isolated from a glacier near the Kunzum Pass located in the Lahaul-Spiti in the North-Western Himalayas of India. The cells were Gram-negative, aerobic, non-sporulating, single rods, lacked flagella, and formed yellow to orange pigmented colonies. The strain utilized maltose, trehalose, sucrose, gentibiose, glucose, mannose, fructose, mannitol, arabitol and salicin for growth. Flexirubin-type pigments were produced by strain IHBB 10212T. The 16S rRNA gene sequence analysis showed relatedness of strain IHBB 10212T to Chryseobacterium polytrichastri DSM 26899T (97.43 %), Chryseobacterium greenlandense CIP 110007T (97.29 %) and Chryseobacterium aquaticum KCTC 12483T (96.80 %). Iso-C15 : 0 and summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) constituted the major cellular fatty acids. The polar lipids present were six unidentified aminolipids, one unidentified phospholipid and three unidentified lipids. MK-6 was identified as the major quinone. The DNA G+C content was 34.08  mol%. Digital DNA-DNA hybridization of strain IHBB 10212T with C. polytrichastri, C. greenlandense and C. aquaticum showed values far below the prescribed thresholds of 95 % for average nucleotide identity and 70 % for the Genome-to-Genome Distance Calculator for species delineation. Based on its differences from validly published Chryseobacterium species, strain IHBB 10212T is identified as a new species, for which the proposed name is Chryseobacterium glaciei sp. nov., with IHBB 10212T as the type strain (=MTCC 12457T=JCM 31156T=KACC 19170T).

Transfersomal Phage Cocktail Is an Effective Treatment against Methicillin-Resistant Staphylococcus aureus-Mediated Skin and Soft Tissue Infections.

The emergence of drug resistance has rekindled interest in phage therapy as an alternative treatment option; its potency, safety, and proven efficacy are worth noting. However, phage therapy still suffers from issues of poor stability, narrow spectra, and poor pharmacokinetic profiles. Therefore, it is essential to look into the use of drug delivery systems for efficient delivery of lytic phages in vivo The present study evaluated the use of nanostructured lipid-based carriers, i.e., transfersomes, as transdermal delivery systems for encapsulating a methicillin-resistant Staphylococcus aureus (MRSA) phage cocktail. Furthermore, the therapeutic potential of the encapsulated phage cocktail in resolving experimental soft tissue infections in rats was studied. Results from in vitro stability and in vivo phage titer experiments indicated that the transfersome-entrapped phage cocktail showed better persistence and stability than did free phages. Rats treated with the transfersome-entrapped phage cocktail resolved the experimental thigh infections within a period of 7 days, unlike the 20-day period required for untreated animals. The findings of the present study support the use of transfersomes as delivery agents to enhance the stability and in vivo persistence of the encapsulated phages. In addition, this study highlights the advantages offered by transfersome-encapsulated phages in providing better therapeutic options than free phages for treating skin and soft tissue infections. The transfersome-entrapped phage cocktail was able to protect all test animals (with no deaths) even when administered with a delay of 12 h postinfection, unlike free phages, thus making this treatment option more suitable for clinical settings.

Azithromycin-Ciprofloxacin-Impregnated Urinary Catheters Avert Bacterial Colonization, Biofilm Formation, and Inflammation in a Murine Model of Foreign-Body-Associated Urinary Tract Infections Caused by Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a multifaceted pathogen causing a variety of biofilm-mediated infections, including catheter-associated urinary tract infections (CAUTIs). The high prevalence of CAUTIs in hospitals, their clinical manifestations, such as urethritis, cystitis, pyelonephritis, meningitis, urosepsis, and death, and the associated economic challenges underscore the need for management of these infections. Biomaterial modification of urinary catheters with two drugs seems an interesting approach to combat CAUTIs by inhibiting biofilm. Previously, we demonstrated the in vitro efficacy of urinary catheters impregnated with azithromycin (AZM) and ciprofloxacin (CIP) against P. aeruginosa Here, we report how these coated catheters impact the course of CAUTI induced by P. aeruginosa in a murine model. CAUTI was established in female LACA mice with uncoated or AZM-CIP-coated silicone implants in the bladder, followed by transurethral inoculation of 108 CFU/ml of biofilm cells of P. aeruginosa PAO1. AZM-CIP-coated implants (i) prevented biofilm formation on the implant's surface (P ≤ 0.01), (ii) restricted bacterial colonization in the bladder and kidney (P < 0.0001), (iii) averted bacteriuria (P < 0.0001), and (iv) exhibited no major histopathological changes for 28 days in comparison to uncoated implants, which showed persistent CAUTI. Antibiotic implants also overcame implant-mediated inflammation, as characterized by trivial levels of inflammatory markers such as malondialdehyde (P < 0.001), myeloperoxidase (P < 0.05), reactive oxygen species (P ≤ 0.001), and reactive nitrogen intermediates (P < 0.01) in comparison to those in uncoated implants. Further, AZM-CIP-coated implants showed immunomodulation by manipulating the release of inflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and IL-10 to the benefit of the host. Overall, the study demonstrates long-term in vivo effectiveness of AZM-CIP-impregnated catheters, which may possibly be a key to success in preventing CAUTIs.

Divalent flagellin immunotherapy provides homologous and heterologous protection in experimental urinary tract infections in mice.

Immunotherapy employs selected prokaryotic elements which are specially targeted because of their designated important role in the pathogenicity of the microbes. Among these is the flagellin of P. aeruginosa, which plays a major role in establishment of urinary tract infections (UTIs). In this study we envisage divalent flagellin (a combination of flagellin subtypes, 'a' and 'b') as an immunotherapeutic candidate against UTIs caused by Pseudomonas aeruginosa. Flagellin proteins were isolated from P. aeruginosa strains and characterized by MALDI-TOF. Their efficacy was checked in an ascending model of UTI. Divalent flagellin ('a' and 'b') when given together (intraperitoneally, i.p.) to female LACA mice at a concentration of 5 µg each, protected mice against pyelonephritis due to P. aeruginosa strains with no bacterial load at peak day of infection. Tissue destruction was minimum, as assessed by MDA levels and renal histopathology. Divalent flagellin immunization also drastically reduced pro-inflammatory cytokine levels (TNF α and IL-1ß) in renal homogenates as determined by ELISA. It also prevented UTI caused by heterologous strain Escherichia coli. Antibodies against both flagellin proteins were assessed by ELISA. Passive immunization protected mice against UTI induced by either of the strains, P. aeruginosa and E. coli. These results confirmed homologous and heterologous protection provided by divalent flagellin.