-
Brazilian Journal of Microbiology :... Jun 2024In recent years, some microorganisms have shown resistance to conventional treatments. Considering this increase in resistant pathogens, treatment alternatives are...
In recent years, some microorganisms have shown resistance to conventional treatments. Considering this increase in resistant pathogens, treatment alternatives are needed to promote greater treatment efficiency. In this sense, antimicrobial photodynamic therapy (aPDT) has been an alternative treatment. This technique uses a photosensitizer that is activated by light with a specific wavelength producing reactive species, leading to the death of pathogenic microorganisms. In this study, bacteriochlorophyll derivatives such as bacteriochlorin metoxi (Bchl-M) and bacteriochlorin trizma (Bchl-T) obtained from purple bacterium (Rhodopseudomonas faecalis), were evaluated as photosensitizers in the aPDT. Photodynamic inactivation (PDI) of the microorganisms Staphylococcus aureus, Micrococcus luteus, Candida albicans and Pseudomonas aeruginosa was investigated with both bacteriochlorins (Bchl-M and Bchl-T) at different concentrations (1, 15 and 30 µM for S. aureus; 1, 15, 30, 45, 60 and 75 µM for M. luteus; 30, 60, 90, 105, 120 and 150 µM for C. albicans; and 200 µM for P. aeruginosa) and different doses of light (20 and 30 J/cm for S. aureus and M. luteus; 30 and 45 J/cm for C. albicans; and 45 J/cm for P. aeruginosa) to inactivate them. Both photosensitizers showed good activation against S. aureus and for M. luteus, we observed the inactivation of these microorganisms at approximately 3 log, showing to be a good photosensitizers for these microorganisms.
Topics: Photosensitizing Agents; Candida albicans; Pseudomonas aeruginosa; Staphylococcus aureus; Light; Photochemotherapy; Porphyrins; Microbial Viability; Micrococcus luteus; Bacteria
PubMed: 38378880
DOI: 10.1007/s42770-024-01278-1 -
Microbiology Spectrum Feb 2024Bacteria absorb different forms of iron through various channels to meet their needs. Our previous studies have shown that TseF, a type VI secretion system effector for...
Bacteria absorb different forms of iron through various channels to meet their needs. Our previous studies have shown that TseF, a type VI secretion system effector for Fe uptake, facilitates the delivery of outer membrane vesicle-associated quinolone signal (PQS)-Fe to bacterial cells by a process involving the Fe(III) pyochelin receptor FptA and the porin OprF. However, the form in which the PQS-Fe complex enters the periplasm and how it is moved into the cytoplasm remain unclear. Here, we first demonstrate that the PQS-Fe complex enters the cell directly through FptA or OprF. Next, we show that inner membrane transporters such as FptX, PchHI, and FepBCDG are not only necessary for to absorb PQS-Fe and pyochelin (PCH)-Fe but are also necessary for the virulence of toward larvae. Furthermore, we suggest that the function of PQS-Fe (but not PQS)-mediated quorum-sensing regulation is dependent on FptX, PchHI, and FepBCDG. Additionally, the findings indicate that unlike FptX, neither FepBCDG nor PchHI play roles in the autoregulatory loop involving PchR, but further deletion of and can reverse the inactive PchR phenotype caused by deletion and reactivate the expression of the PCH pathway genes under iron-limited conditions. Finally, this work identifies the interaction between FptX, PchHI, and FepBCDG, indicating that a larger complex could be formed to mediate the uptake of PQS-Fe and PCH-Fe. These results pave the way for a better understanding of the PQS and PCH iron absorption pathways and provide future directions for research on tackling infections.IMPORTANCE has evolved a number of strategies to acquire the iron it needs from its host, with the most common being the synthesis, secretion, and uptake of siderophores such as pyoverdine, pyochelin, and the quorum-sensing signaling molecule quinolone signal (PQS). However, despite intensive studies of the siderophore uptake pathways of , our understanding of how siderophores transport iron across the inner membrane into the cytoplasm is still incomplete. Herein, we reveal that PQS and pyochelin in share inner membrane transporters such as FptX, PchHI, and FepBCDG to mediate iron uptake. Meanwhile, PQS and pyochelin-mediated signaling operate to a large extent via these inner membrane transporters. Our study revealed the existence of shared uptake pathways between PQS and pyochelin, which could lead us to reexamine the role of these two molecules in the iron uptake and virulence of .
Topics: Iron; Pseudomonas aeruginosa; Membrane Transport Proteins; Receptors, Cell Surface; Bacterial Outer Membrane Proteins; Siderophores; Bacterial Proteins; Phenols; Thiazoles; Quinolones
PubMed: 38171001
DOI: 10.1128/spectrum.03256-23 -
Frontiers in Cellular and Infection... 2023Polymicrobial infections include various microorganisms, often necessitating different treatment methods than a monomicrobial infection. Scientists have been puzzled by... (Review)
Review
Polymicrobial infections include various microorganisms, often necessitating different treatment methods than a monomicrobial infection. Scientists have been puzzled by the complex interactions within these communities for generations. The presence of specific microorganisms warrants a chronic infection and impacts crucial factors such as virulence and antibiotic susceptibility. Game theory is valuable for scenarios involving multiple decision-makers, but its relevance to polymicrobial infections is limited. Eco-evolutionary dynamics introduce causation for multiple proteomic interactions like metabolic syntropy and niche segregation. The review culminates both these giants to form evolutionary dynamics (ED). There is a significant amount of literature on inter-bacterial interactions that remain unsynchronised. Such raw data can only be moulded by analysing the ED involved. The review culminates the inter-bacterial interactions in multiple clinically relevant polymicrobial infections like chronic wounds, CAUTI, otitis media and dental carries. The data is further moulded with ED to analyse the niche colonisation of two notoriously competitive bacteria: and . The review attempts to develop a future trajectory for polymicrobial research by following recent innovative strategies incorporating ED to curb polymicrobial infections.
Topics: Humans; Coinfection; Proteomics; Staphylococcus aureus; Bacteria; Virulence; Pseudomonas aeruginosa
PubMed: 38145044
DOI: 10.3389/fcimb.2023.1295063 -
The Journal of General and Applied... Dec 2023The Pseudomonas aeruginosa strain, PAO1, has three putative γ-glutamyltranspeptidase (GGT) genes: ggtI, ggtII, and ggtIII. In this study, the expression of each of...
The Pseudomonas aeruginosa strain, PAO1, has three putative γ-glutamyltranspeptidase (GGT) genes: ggtI, ggtII, and ggtIII. In this study, the expression of each of these genes in P. aeruginosa PAO1 was analyzed, and the properties of the corresponding GGT proteins were investigated. This is the first report on biochemical characterization of GGT paralogs from Pseudomonas species. The crude extracts prepared from P. aeruginosa PAO1 exhibited hydrolysis and transpeptidation activities of 17.3 and 65.0 mU/mg, respectively, and the transcription of each gene to mRNA was confirmed by RT-PCR. All genes were cloned, and the expression plasmids constructed were introduced into an Escherichia coli expression system. Enzyme activity of the expressed protein of ggtI (PaGGTI) was not detected in the system, while the enzyme activities of the expressed proteins derived from ggtII and ggtIII (PaGGTII and PaGGTIII, respectively) were detected. However, the enzyme activity of PaGGTII was very low and easily decreased. PaGGTII with C-terminal his-tag (PaGGTII25aa) showed increased activity and stability, and the purified enzyme consisted of a large subunit of 40 kDa and a small subunit of 28 kDa. PaGGTIII consisted of a large subunit of 37 kDa and a small subunit of 24 kDa. The maximum hydrolysis and transpeptidation activities of PaGGTII25aa were obtained at 40ºC-50ºC, and the maximum hydrolysis and transpeptidation activities of PaGGTIII were obtained at 50ºC-60ºC. These enzymes retained approximately 80% of their hydrolysis and transpeptidation activities after incubation at 50ºC for 10 min, reflecting good stability. Both PaGGTII25aa and PaGGTIII showed higher activities of hydrolysis and transpeptidation in the alkali range than in the acidic range. However, they were highly stable at a wide pH range (5-10.5).
Topics: Humans; Pseudomonas aeruginosa; Pseudomonas; Pseudomonas Infections; Escherichia coli
PubMed: 36653156
DOI: 10.2323/jgam.2023.01.001 -
Virus Research Oct 2023Multiple drug-resistant (MDR) Pseudomonas aeruginosa commonly causes severe hospital-acquired infections. The gradual emergence of carbapenem-resistant P. aeruginosa has...
Multiple drug-resistant (MDR) Pseudomonas aeruginosa commonly causes severe hospital-acquired infections. The gradual emergence of carbapenem-resistant P. aeruginosa has recently gained attention. A wide array of P. aeruginosa-mediated pathogenic mechanisms, including its biofilm-forming ability, limits the use of effective antimicrobial treatments against it. In the present study, we isolated and characterized the phenotypic, biological, and genomic characteristics of a bacteriophage, vB_PaP_phiPA1-3 (phiPA1-3). Biofilm eradication and phage rescue from bacterial infections were assessed to demonstrate the efficacy of the application potential. Host range spectrum analysis revealed that phiPA1-3 is a moderate host range phage that infects 20% of the clinically isolated strains of P. aeruginosa tested, including carbapenem-resistant P. aeruginosa (CRPA). The phage exhibited stability at pH 7.0 and 9.0, with significantly reduced viability below pH 5.0 and beyond pH 9.0. phiPA1-3 is a lytic phage with a burst size of 619 plaque-forming units/infected cell at 37 °C and can effectively lyse bacteria in a multiplicity of infection-dependent manner. The genome size of phiPA1-3 was found to be 73,402 bp, with a G+C content of 54.7%, containing 93 open reading frames, of which 62 were annotated as hypothetical proteins and the remaining 31 had known functions. The phage possesses several proteins similar to those found in N4-like phages, including three types of RNA polymerases. This study concluded that phiPA1-3 belongs to the N4-like Schitoviridae family, can potentially eradicate P. aeruginosa biofilms, and thus, serve as a valuable tool for controlling CRPA infections.
Topics: Bacteriophages; Pseudomonas aeruginosa; Pseudomonas Phages; Genomics; Carbapenems
PubMed: 37490958
DOI: 10.1016/j.virusres.2023.199178 -
Journal of Applied Microbiology Aug 2023The aim of this study was to explore the decolourization and bioremediation ability of non-encapsulated and encapsulated Pseudomonas aeruginosa (strain KBN 12) against...
AIM
The aim of this study was to explore the decolourization and bioremediation ability of non-encapsulated and encapsulated Pseudomonas aeruginosa (strain KBN 12) against the azo dye brilliant blue (BB).
METHODS AND RESULTS
Six efficient BB dye-decolourizing bacteria were isolated from textile dye effluent. The most efficient free cells of P. aeruginosa KBN 12 along with the optimized conditions such as carbon source (maltose: 5 g L-1), and nitrogen source (ammonium chloride: 4 g L-1) at pH 6 at 37°C decolourized 72.69% of BB dye aerobically after 9 days of incubation under static conditions. Encapsulated (calcium alginate) P. aeruginosa KBN 12 decolourized 87.67% of BB dye aerobically after 9 days of incubation under the same optimized conditions. Fourier-transform infrared spectroscopy (FTIR) and gas chromatography (GC) analysis of the chemical structure of BB dye after decolourization found changes in functional and chemical groups. Phytotoxicity and soil respiration enzyme assays revealed that the decolourized dye or dye products were less toxic than the pure BB dye.
CONCLUSION
The encapsulation of P. aeruginosa KBN 12 proved to be an effective method for BB dye decolourization or remediation.
Topics: Vigna; Pseudomonas aeruginosa; Benzenesulfonates; Alginates
PubMed: 37596094
DOI: 10.1093/jambio/lxad189 -
PLoS Pathogens May 2024Mucosa-associated biofilms are associated with many human disease states, but the host mechanisms promoting biofilm remain unclear. In chronic respiratory diseases like...
Mucosa-associated biofilms are associated with many human disease states, but the host mechanisms promoting biofilm remain unclear. In chronic respiratory diseases like cystic fibrosis (CF), Pseudomonas aeruginosa establishes chronic infection through biofilm formation. P. aeruginosa can be attracted to interspecies biofilms through potassium currents emanating from the biofilms. We hypothesized that P. aeruginosa could, similarly, sense and respond to the potassium efflux from human airway epithelial cells (AECs) to promote biofilm. Using respiratory epithelial co-culture biofilm imaging assays of P. aeruginosa grown in association with CF bronchial epithelial cells (CFBE41o-), we found that P. aeruginosa biofilm was increased by potassium efflux from AECs, as examined by potentiating large conductance potassium channel, BKCa (NS19504) potassium efflux. This phenotype is driven by increased bacterial attachment and increased coalescence of bacteria into aggregates. Conversely, biofilm formation was reduced when AECs were treated with a BKCa blocker (paxilline). Using an agar-based macroscopic chemotaxis assay, we determined that P. aeruginosa chemotaxes toward potassium and screened transposon mutants to discover that disruption of the high-sensitivity potassium transporter, KdpFABC, and the two-component potassium sensing system, KdpDE, reduces P. aeruginosa potassium chemotaxis. In respiratory epithelial co-culture biofilm imaging assays, a KdpFABCDE deficient P. aeruginosa strain demonstrated reduced biofilm growth in association with AECs while maintaining biofilm formation on abiotic surfaces. Furthermore, we determined that the Kdp operon is expressed in vivo in people with CF and the genes are conserved in CF isolates. Collectively, these data suggest that P. aeruginosa biofilm formation can be increased by attracting bacteria to the mucosal surface and enhancing coalescence into microcolonies through aberrant AEC potassium efflux sensed by the KdpFABCDE system. These findings suggest host electrochemical signaling can enhance biofilm, a novel host-pathogen interaction, and potassium flux could be a therapeutic target to prevent chronic infections in diseases with mucosa-associated biofilms, like CF.
Topics: Biofilms; Pseudomonas aeruginosa; Humans; Cystic Fibrosis; Epithelial Cells; Operon; Potassium; Pseudomonas Infections; Bacterial Proteins; Respiratory Mucosa
PubMed: 38820569
DOI: 10.1371/journal.ppat.1011453 -
The Journal of Antibiotics Jul 2024Antibiotic resistance is a major health problem worldwide. Pseudomonas aeruginosa is a Gram-negative pathogen with an arsenal of virulence factors and elevated...
Antibiotic resistance is a major health problem worldwide. Pseudomonas aeruginosa is a Gram-negative pathogen with an arsenal of virulence factors and elevated antimicrobial resistance. It is a leading cause of nosocomial infections with high morbidity and mortality. The significant time and effort required to develop new antibiotics can be circumvented using alternative therapeutic strategies, including anti-virulence targets. This study aimed to investigate the anti-virulence activity of the FDA-approved drugs miconazole and phenothiazine against P. aeruginosa. The phenotypic effect of sub-inhibitory concentrations of miconazole and phenothiazine on biofilm, pyocyanin, protease, rhamnolipid and hemolysin activities in PAO1 strain was examined. qRT-PCR was used to assess the effect of drugs on quorum-sensing genes that regulate virulence. Further, the anti-virulence potential of miconazole and phenothiazine was evaluated in silico and in vivo. Miconazole showed significant inhibition of Pseudomonas virulence by reducing biofilm-formation approximately 45-48%, hemolytic-activity by 59%, pyocyanin-production by 47-49%, rhamnolipid-activity by approximately 42-47% and protease activity by 36-40%. While, phenothiazine showed lower anti-virulence activity, it inhibited biofilm (31-35%), pyocyanin (37-39%), protease (32-40%), rhamnolipid (35-40%) and hemolytic activity (47-56%). Similarly, there was significantly reduced expression of RhlR, PqsR, LasI and LasR following treatment with miconazole, but less so with phenothiazine. In-silico analysis revealed that miconazole had higher binding affinity than phenothiazine to LasR, RhlR, and PqsR QS-proteins. Furthermore, there was 100% survival in mice injected with PAO1 treated with miconazole. In conclusion, miconazole and phenothiazine are promising anti-virulence agents for P. aeruginosa.
Topics: Pseudomonas aeruginosa; Quorum Sensing; Miconazole; Phenothiazines; Biofilms; Virulence; Anti-Bacterial Agents; Animals; Microbial Sensitivity Tests; Pyocyanine; Pseudomonas Infections; Virulence Factors; Mice; Molecular Docking Simulation; Glycolipids
PubMed: 38724627
DOI: 10.1038/s41429-024-00731-5 -
Methods in Molecular Biology (Clifton,... 2024Proteolytic activity plays an essential role in Pseudomonas aeruginosa adaptation and survival in challenging environments, including the infection site. Here, a short...
Proteolytic activity plays an essential role in Pseudomonas aeruginosa adaptation and survival in challenging environments, including the infection site. Here, a short review of the eight known proteases secreted by P. aeruginosa and of the methods used to detect their activity is provided. In addition, three simple and handy methods routinely used in our laboratory to detect proteases are described in detail. In particular, the skim milk plate assay and the azocasein assay are useful for the detection of whole proteases activity in colony-growing and cell-free culture supernatants, respectively. Conversely, the Elastin Congo-red assay allows detecting the activity of the LasB elastase, the major protease secreted by P. aeruginosa, in cell-free culture supernatants.
Topics: Humans; Animals; Pseudomonas aeruginosa; Peptide Hydrolases; Pancreatic Elastase; Proteolysis; Milk; Bacterial Proteins; Pseudomonas Infections
PubMed: 37819520
DOI: 10.1007/978-1-0716-3473-8_10 -
European Journal of Medicinal Chemistry Nov 2023Pseudomonas aeruginosa (P. aeruginosa) is a gram-negative pathogenic bacterium, often causative drug-resistance related human infections, given its great capacity to...
Pseudomonas aeruginosa (P. aeruginosa) is a gram-negative pathogenic bacterium, often causative drug-resistance related human infections, given its great capacity to form bioflm. It uses three major quorum sensing (QS) systems, las, rhl, and pqs, to regulate the expression of genes related to virulence and biofilm formation. Consequently, strategies for inhibiting QS have garnered considerable attention as antimicrobial therapies. In this study, we designed and synthesized several 3-hydroxypyridin-4(1H)-one hybrids and assessed their potential as the inhibitors of P. aeruginosa biofilm formation. The most active compound identified was 12h; it exhibited satisfactory biofilm inhibitory activity (IC: 10.59 ± 1.17 μM). Mechanistic studies revealed that 12h significantly inhibited the fluorescence of the PAO1-lasB-gfp and PAO1-pqsA-gfp fluorescent reporter strains and the production of Las-regulated (elastase) and Pqs-regulated (pyocyanin) virulence factors. These findings indicate that 12h inhibited biofilm formation by suppressing the expression of lasB and pqsA, thereby inactivating the las and pqs pathways. Furthermore, 12h improved the antibiotic susceptibility of P. aeruginosa and reduced the acute virulence of this bacterium in the African green monkey kidney cell line Vero. In conclusion, 3-hydroxypyridin-4(1H)-one hybrids, such as 12h, represent a promising class of antibacterial agents against P. aeruginosa.
Topics: Animals; Humans; Chlorocebus aethiops; Pseudomonas aeruginosa; Biofilms; Quorum Sensing; Virulence Factors; Virulence; Anti-Bacterial Agents; Bacterial Proteins
PubMed: 37506546
DOI: 10.1016/j.ejmech.2023.115665