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Annals of Laboratory Medicine Jan 2024
Topics: Humans; Pseudomonas aeruginosa; Anti-Bacterial Agents; Infection Control; Carbapenems
PubMed: 37665279
DOI: 10.3343/alm.2024.44.1.1 -
The Lancet. Microbe Sep 2023
Topics: Virulence; Pseudomonas aeruginosa; Anti-Bacterial Agents; Carbapenems; China
PubMed: 37327803
DOI: 10.1016/S2666-5247(23)00113-1 -
Microbial Cell Factories Aug 2023Pyocyanin is a secondary metabolite secreted by P. aeruginosa. It is a redox-active blue/green phenazine pigment that has various beneficial applications. The present...
BACKGROUND
Pyocyanin is a secondary metabolite secreted by P. aeruginosa. It is a redox-active blue/green phenazine pigment that has various beneficial applications. The present study aims at screening the production of pyocyanin among clinical and environmental P. aeruginosa isolates in Dakahlya governorate, Egypt. Thereafter, large-scale production, purification, structure elucidation, and assessment of the biological activity of the highest pyocyanin producers were targeted.
RESULTS
Pyocyanin from the highest clinical (PsC05) and environmental (PsE02) producers were subjected to large-scale production, followed by purification using silica gel column. Pyocyanin was characterized using TLC, UV-Vis, H NMR, and FTIR spectroscopy to confirm its structure and purity. Purified pyocyanin showed remarkable antimicrobial efficacy against all tested food-borne pathogens, MDR/XDR clinically isolated bacteria and C. albicans. Furthermore, it showed a substantial effect on biofilm inhibition and eradication of pre-formed biofilm against strong biofilm producing bacterial pathogens. However, it had limited antibiofilm activity against C. albicans. Pyocyanin from PsC05 had higher antioxidant and radicals scavenging activity than that from PsE02 as determined by FRAP, DPPH, and ABTS assays. Likewise, pyocyanin from PsC05 was more active against tested cancer cell lines, especially human Breast Cancer (MCF-7) and Colorectal Carcinoma (HCT-116), than that from PsE02. More importantly, it showed minimal cytotoxicity to normal cells.
CONCLUSIONS
P. aeruginosa clinical and environmental isolates produce pyocyanin pigment in varying amounts. Pyocyanin exhibits substantial anti-bacterial, and anti-fungal activity; thus, enhancing its medical applicability. It could be used to inhibit and/or eradicate biofilm from the surfaces of medical devices which is a chief source of nosocomial infections. Its antioxidant along with cytotoxic activity against cancer cell lines, make it a promising contender for use as a substitute for synthetic agents in cancer treatment.
Topics: Humans; Pyocyanine; Antioxidants; Pseudomonas aeruginosa; Biofilms; Biological Assay; Candida albicans
PubMed: 37644606
DOI: 10.1186/s12934-023-02169-0 -
Intracellular replication of in epithelial cells requires suppression of the caspase-4 inflammasome.MSphere Oct 2023Pathogenesis of infections can include bacterial survival inside epithelial cells. Previously, we showed that this involves multiple roles played by the type three...
Pathogenesis of infections can include bacterial survival inside epithelial cells. Previously, we showed that this involves multiple roles played by the type three secretion system (T3SS), and specifically the effector ExoS. This includes ExoS-dependent inhibition of a lytic host cell response that subsequently enables intracellular replication. Here, we studied the underlying cell death response to intracellular , comparing wild-type to T3SS mutants varying in capacity to induce cell death and that localize to different intracellular compartments. Results showed that corneal epithelial cell death induced by intracellular lacking the T3SS, which remains in vacuoles, correlated with the activation of nuclear factor-κB as measured by p65 relocalization and tumor necrosis factor alpha transcription and secretion. Deletion of caspase-4 through CRISPR-Cas9 mutagenesis delayed cell death caused by these intracellular T3SS mutants. Caspase-4 deletion also countered more rapid cell death caused by T3SS effector-null mutants still expressing the T3SS apparatus that traffic to the host cell cytoplasm, and in doing so rescued intracellular replication normally dependent on ExoS. While HeLa cells lacked a lytic death response to T3SS mutants, it was found to be enabled by interferon gamma treatment. Together, these results show that epithelial cells can activate the noncanonical inflammasome pathway to limit proliferation of intracellular , not fully dependent on bacterially driven vacuole escape. Since ExoS inhibits the lytic response, the data implicate targeting of caspase-4, an intracellular pattern recognition receptor, as another contributor to the role of ExoS in the intracellular lifestyle of . IMPORTANCE can exhibit an intracellular lifestyle within epithelial cells and . The type three secretion system (T3SS) effector ExoS contributes via multiple mechanisms, including extending the life of invaded host cells. Here, we aimed to understand the underlying cell death inhibited by ExoS when is intracellular. Results showed that intracellular lacking T3SS effectors could elicit rapid cell lysis via the noncanonical inflammasome pathway. Caspase-4 contributed to cell lysis even when the intracellular bacteria lacked the entire T33S and were consequently unable to escape vacuoles, representing a naturally occurring subpopulation during wild-type infection. Together, the data show the caspase-4 inflammasome as an epithelial cell defense against intracellular , and implicate its targeting as another mechanism by which ExoS preserves the host cell replicative niche.
Topics: Humans; HeLa Cells; Pseudomonas aeruginosa; Inflammasomes; Epithelial Cells; Vacuoles
PubMed: 37589460
DOI: 10.1128/msphere.00351-23 -
Direct prediction of carbapenem resistance in by whole genome sequencing and metagenomic sequencing.Journal of Clinical Microbiology Nov 2023Carbapenem resistance is a major concern in the management of antibiotic-resistant infections. The direct prediction of carbapenem-resistant phenotype from genotype in...
Carbapenem resistance is a major concern in the management of antibiotic-resistant infections. The direct prediction of carbapenem-resistant phenotype from genotype in isolates and clinical samples would promote timely antibiotic therapy. The complex carbapenem resistance mechanism and the high prevalence of variant-driven carbapenem resistance in make it challenging to predict the carbapenem-resistant phenotype through the genotype. In this study, using whole genome sequencing (WGS) data of 1,622 . isolates followed by machine learning, we screened 16 and 31 key gene features associated with imipenem (IPM) and meropenem (MEM) resistance in , including oprD(HIGH), and constructed the resistance prediction models. The areas under the curves of the IPM and MEM resistance prediction models were 0.906 and 0.925, respectively. For the direct prediction of carbapenem resistance in from clinical samples by the key gene features selected and prediction models constructed, 72 . -positive sputum samples were collected and sequenced by metagenomic sequencing (MGS) based on next-generation sequencing (NGS) or Oxford Nanopore Technology (ONT). The prediction applicability of MGS based on NGS outperformed that of MGS based on ONT. In 72 . -positive sputum samples, 65.0% (26/40) of IPM-insensitive and 63.2% (24/38) of MEM-insensitive were directly predicted by NGS-based MGS with positive predictive values of 0.897 and 0.889, respectively. By the direct detection of the key gene features associated with carbapenem resistance of , the carbapenem resistance of could be directly predicted from cultured isolates by WGS or from clinical samples by NGS-based MGS, which could assist the timely treatment and surveillance of carbapenem-resistant .
Topics: Humans; Pseudomonas aeruginosa; Pseudomonas Infections; Bacterial Proteins; Microbial Sensitivity Tests; Anti-Bacterial Agents; Meropenem; Carbapenems; Whole Genome Sequencing; beta-Lactamases; Porins; Drug Resistance, Bacterial
PubMed: 37823665
DOI: 10.1128/jcm.00617-23 -
MSphere Aug 2023Prophages are bacteriophages integrated into the bacterial host's chromosome. This research aims to analyze and characterize the existing prophages within a collection...
Prophages are bacteriophages integrated into the bacterial host's chromosome. This research aims to analyze and characterize the existing prophages within a collection of 53 strains from intensive care units (ICUs) in Portugal and Spain. A total of 113 prophages were localized in the collection, with 18 of them being present in more than one strain simultaneously. After annotation, five of them were discarded as incomplete, and the 13 remaining prophages were characterized. Of 13, 10 belonged to the siphovirus tail morphology group, 2 to the podovirus tail morphology group, and 1 to the myovirus tail morphology group. All prophages had a length ranging from 20,199 to 63,401 bp and a GC% between 56.2% and 63.6%. The number of open reading frames (ORFs) oscillated between 32 and 88, and in 3/13 prophages, more than 50% of the ORFs had an unknown function. With our findings, we show that prophages are present in the majority of the strains isolated from Portuguese and Spanish critically ill patients, many of them found in more than one circulating strain at the same time and following a similar clonal distribution pattern. Although a great sum of ORFs had an unknown function, number of proteins in relation to viral defense (anti-CRISPR proteins, toxin/antitoxin modules, proteins against restriction-modification systems) as well as to prophage interference into their host's quorum sensing system and regulatory cascades were found. This supports the idea that prophages have an influence in bacterial pathogenesis and anti-phage defense. IMPORTANCE Despite being known for decades, prophages remain understudied when compared to the lytic phages employed in phage therapy. This research aims to shed some light into the nature, composition, and role of prophages found within a set of circulating strains of , with special attention to high-risk clones. Given the fact that prophages can effectively influence bacterial pathogenesis, prophage basic research constitutes a topic of growing interest. Furthermore, the abundance of viral defense and regulatory proteins within prophage genomes detected in this study evidences the importance of characterizing the most frequent prophages in circulating clinical strains and in high-risk clones if phage therapy is to be used.
Topics: Humans; Prophages; Pseudomonas aeruginosa; Genome, Viral; Critical Care; Spain
PubMed: 37366636
DOI: 10.1128/msphere.00128-23 -
Microbial Biotechnology Jul 2023Pseudomonas aeruginosa is an opportunistic pathogen able to infect any human tissue. One of the reasons for its high adaptability and colonization of host tissues is its... (Review)
Review
Pseudomonas aeruginosa is an opportunistic pathogen able to infect any human tissue. One of the reasons for its high adaptability and colonization of host tissues is its capacity of maintaining iron homeostasis through a wide array of iron acquisition and removal mechanisms. Due to their ability to cause life-threatening acute and chronic infections, especially among cystic fibrosis and immunocompromised patients, and their propensity to acquire resistance to many antibiotics, the World Health Organization (WHO) has encouraged the scientific community to find new strategies to eradicate this pathogen. Several recent strategies to battle P. aeruginosa focus on targeting iron homeostasis mechanisms, turning its greatest advantage into an exploitable weak point. In this review, we discuss the different mechanisms used by P. aeruginosa to maintain iron homeostasis and the strategies being developed to fight this pathogen by blocking these mechanisms. Among others, the use of iron chelators and mimics, as well as disruption of siderophore production and uptake, have shown promising results in reducing viability and/or virulence of this pathogen. The so-called 'Trojan-horse' strategy taking advantage of the siderophore uptake systems is emerging as an efficient method to improve delivery of antibiotics into the bacterial cells. Moreover, siderophore transporters are considered promising targets for the developing of P. aeruginosa vaccines.
Topics: Humans; Pseudomonas aeruginosa; Siderophores; Iron; Homeostasis; Anti-Bacterial Agents; Pseudomonas Infections
PubMed: 36857468
DOI: 10.1111/1751-7915.14241 -
ACS Infectious Diseases Jul 2023Traditional antibacterial screens rely on growing bacteria in nutrient-replete conditions which are not representative of the natural environment or sites of infection....
Traditional antibacterial screens rely on growing bacteria in nutrient-replete conditions which are not representative of the natural environment or sites of infection. Instead, screening in more physiologically relevant conditions may reveal novel activity for existing antibiotics. Here, we screened a panel of antibiotics reported to lack activity against the opportunistic Gram-negative bacterium, , under low-nutrient and low-iron conditions, and discovered that the glycopeptide vancomycin inhibited the growth of at low micromolar concentrations through its canonical mechanism of action, disruption of peptidoglycan crosslinking. Spontaneous vancomycin-resistant mutants underwent activating mutations in the sensor kinase of the two-component CpxSR system, which induced cross-resistance to almost all classes of β-lactams, including the siderophore antibiotic cefiderocol. Other mutations that conferred vancomycin resistance mapped to WapR, an α-1,3-rhamnosyltransferase involved in lipopolysaccharide core biosynthesis. A WapR P164T mutant had a modified LPS profile compared to wild type that was accompanied by increased susceptibility to select bacteriophages. We conclude that screening in nutrient-limited conditions can reveal novel activity for existing antibiotics and lead to discovery of new and impactful resistance mechanisms.
Topics: Vancomycin; Pseudomonas aeruginosa; Anti-Bacterial Agents; Glycopeptides; Nutrients
PubMed: 37279282
DOI: 10.1021/acsinfecdis.3c00167 -
Applied Microbiology and Biotechnology Dec 2024With the inappropriate use of antibiotics, antibiotic resistance has emerged as a major dilemma for patients infected with Pseudomonas aeruginosa. Elastase B (LasB), a...
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.
Topics: Humans; Quercetin; Virulence; Pseudomonas aeruginosa; Molecular Docking Simulation; Pancreatic Elastase
PubMed: 38180553
DOI: 10.1007/s00253-023-12890-w -
Virus Research Oct 2023Pseudomonas aeruginosa is a clinically common conditionally pathogenic bacterium, and the abuse of antibiotics has exacerbated its drug resistance in recent years. This...
Pseudomonas aeruginosa is a clinically common conditionally pathogenic bacterium, and the abuse of antibiotics has exacerbated its drug resistance in recent years. This has resulted in extensive reports about the usage of Pseudomonas aeruginosa phage as a novel antibacterial drug. In this study, we isolated a novel phage HZ2201 with a broad lytic spectrum. The lytic rate of this phage against Pseudomonas aeruginosa reached 78.38% (29/37), including 25 multi-drug- and carbapenem-resistant Pseudomonas aeruginosa strains. Transmission electron microscopy revealed that phage HZ2201 belongs to the class Caudoviricetes. Biological characterization showed that phage HZ2201 had an latent period of 40 min, a lytic period of 20 min, and a burst size of 440 PFU/cell, with improved tolerance to temperature and pH. Considering genomic analysis, the HZ2201 genome was a circular double-stranded DNA with a size of 45,431 bp and a guanine-cytosine (G + C) content of 52.16%, and contained 3 tRNAs. 27 of the 74 open reading frames (ORFs) annotated by the Rapid Annotation using Subsystem Technology (RAST) tool could be matched to the genomes of known functions, and no genes related to virulence and antibiotic resistance were found. The phylogenetic tree suggests that phage HZ2201 is highly related to the phage ZCPS1 and PaP3, and ORF57 and ORF17 are predicted to encode a holin and an endolysin, respectively. Cell lysis by HZ2201 proceeds through the holin-endolysin system, suggesting that it is a novel phage. Additionally, we demonstrated that phage HZ2201 has a high inhibitory capacity against Pseudomonas aeruginosa biofilms. The results of our study suggest that phage HZ2201 is a novel potential antimicrobial agent for treating drug-resistant Pseudomonas aeruginosa infection.
Topics: Bacteriophages; Pseudomonas aeruginosa; Phylogeny; Pseudomonas Phages; Genomics; Genome, Viral; Biofilms
PubMed: 37532140
DOI: 10.1016/j.virusres.2023.199184