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International Journal of Antimicrobial... Jun 2024Polymyxin B, with its unique structure and mechanism of action, has emerged as a key therapeutic agent against Gram-negative bacteria. The study aims to explore...
PURPOSE
Polymyxin B, with its unique structure and mechanism of action, has emerged as a key therapeutic agent against Gram-negative bacteria. The study aims to explore potential factors to influence its effectiveness and safety.
METHODS
A Model-Based Meta-Analysis (MBMA) of 96 articles was conducted, focusing on factors like dosage, bacterial species, and combined antibiotic therapy. The analysis evaluated mortality rates and incidence rate of renal dysfunction, also employing parametric survival models to assess 30-day survival rates.
RESULTS
In the study involving 96 articles and 9,716 patients, polymyxin B's daily dose showed minimal effect on overall mortality, with high-dose group mortality at 33.57% (95% CI: 29.15-38.00) compared to the low-dose group at 35.44% (95% CI: 28.99-41.88), p=0.64. Mortality significantly varied by bacterial species, with Pseudomonas aeruginosa infections at 58.50% (95% CI: 55.42-63.58). Monotherapy exhibited the highest mortality at 40.25% (95% CI: 34.75-45.76), p<0.01. Renal dysfunction was more common in high-dose patients at 29.75% (95% CI: 28.52-30.98), with no significant difference across antibiotic regimens, p=0.54. The 30-day Overall Survival rate for monotherapy therapy was 63.6% (95% CI: 59.3-67.5) and 70.2% (95% CI: 64.4-76.2) for association therapy with β-lactam drugs.
CONCLUSIONS
The dosage of Polymyxin B doesn't significantly change death rates, but its effectiveness varies based on the bacterial infection. Certain bacteria like Pseudomonas aeruginosa are associated with higher mortality. Combining Polymyxin B with other antibiotics, especially β-lactam drugs, improves survival rates. Side effects depend on the dose, with lower doses being safer. These findings emphasize the importance of customizing treatment to balance effectiveness and safety.
PubMed: 38945178
DOI: 10.1016/j.ijantimicag.2024.107262 -
International Journal of Antimicrobial... Jun 2024The proliferation of metallo-beta-lactamase-producing Pseudomonas aeruginosa represents a significant public health threat. P. aeruginosa can undergo significant...
OBJECTIVES
The proliferation of metallo-beta-lactamase-producing Pseudomonas aeruginosa represents a significant public health threat. P. aeruginosa can undergo significant phenotypic changes that can drastically impair antibiotic efficacy. This study's objectives were (1) to quantify the time-course of killing of VIM-2-producing P. aeruginosa in response to aztreonam-based therapies (including avibactam for coverage of AmpC), and (2) to document the capacity of P. aeruginosa to undergo morphological transformations that facilitate persistence.
METHODS
A well-characterized, clinical VIM-2-producing P. aeruginosa was studied in the Hollow Fiber Infection Model (HFIM) over 9 days (7 days of active antibiotic therapy, 2 days treatment withdrawal) at a 10 CFU/mL starting inoculum. HFIM treatment arms included: growth control, aztreonam, ceftazidime/avibactam, aztreonam/ceftazidime/avibactam, polymyxin B, and aztreonam/ceftazidime/avibactam/polymyxin B. In addition, real-time imaging studies were conducted under static conditions to determine the time-course of the reversion of persister cells.
RESULTS
A pronounced discrepancy was observed between OD and bacterial counts obtained from plating methods (hereafter referred to as 'OD-count discrepancy'). For aztreonam monotherapy, observed counts were 0 CFU/mL by 120 h. Despite this, there was a significant OD-count discrepancy as compared to the pre-treatment 0h. Between therapy withdrawal at 168h and 216h, all arms with suppressed counts had re-grown to the system carrying capacity. Real-time imaging of the P. aeruginosa filaments after drug removal showed rapid reversion from a long, filamentous phenotype to many individual rods within 2 h.
CONCLUSION
Managing MBL-producing P. aeruginosa will require a multi-faceted approach, focused on maximizing killing and minimizing proliferation of resistant and persistent subpopulations, which will involve eliminating drug-induced phenotypic transformers.
PubMed: 38945177
DOI: 10.1016/j.ijantimicag.2024.107260 -
International Journal of Biological... Jun 2024The article explores the synthesis of network hydrogels derived from moringa gum (MG) through a grafting reaction with poly (vinylsulfonic acid) and carbopol. These...
The article explores the synthesis of network hydrogels derived from moringa gum (MG) through a grafting reaction with poly (vinylsulfonic acid) and carbopol. These hydrogels are designed for use in drug delivery (DD) and wound hydrogels dressing (HYDR) applications. The copolymers were characterized by FESEM, EDX, AFM, FTIR, C NMR, XRD and DSC. Tetracycline release from hydrogel occurred gradually with a non-Fickian diffusion and was best described by the Hixson-Crowell kinetic model in artificial wound fluid. The HYDR demonstrated compatibility with blood, exhibited antioxidant properties and possessed tensile strength, in addition to their mucoadhesive characteristics. The copolymer dressings absorbed approximately 7 g of simulated fluid. The copolymers exhibited significant antioxidant activity, measuring at 84 % free radicals scavenging, during DPPH assay. These dressings demonstrated permeability to HO and O. The hydrogel alone did not reveal antibacterial activities; however, when combined with antibiotic drug tetracycline, the dressings revealed notable antibacterial activities against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The observed biomedical properties suggested that these hydrogels could serve as promising materials for drug delivery HYDR applications.
PubMed: 38945716
DOI: 10.1016/j.ijbiomac.2024.133352 -
Mymensingh Medical Journal : MMJ Jul 2024Water related diseases are of great concern in developing countries like Bangladesh. Every year, many people die due to consumption of unsafe drinking water. In order to... (Observational Study)
Observational Study
Water related diseases are of great concern in developing countries like Bangladesh. Every year, many people die due to consumption of unsafe drinking water. In order to protect public health it is compulsory that the accessible drinking water should be maximum quality. In this descriptive observational study 150 samples of bottled water and 150 jar water samples were collected from different shops and restaurants. Each sample were filtered through a membrane filter and then placed on MacConkey agar media for total and fecal coliform count and 0.1 ml of water spread on nutrient agar media for heterotrophic plate count (HPC). Among 150 bottled water samples 11 (7.33%) were culture positive and 92 (61.33%) were culture positive in 150 jar water samples. Out of 150 jar water samples 38 (25.33%) were total coliform and among them 19 (12.67%) were fecal coliform. Among 300 water samples 55 (53.40%) samples showed HPC greater than 500 CFU/ml. A total of 9 bacterial isolates: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter spp. CONS, Aeromonas spp., Enterobacter spp., Klebsiella spp. and Citrobacter were found.
Topics: Drinking Water; Water Microbiology; Humans; Bangladesh
PubMed: 38944733
DOI: No ID Found -
Mymensingh Medical Journal : MMJ Jul 2024Antibiotics' usefulness is threatened by multi-drugs resistance in harmful microorganisms because of abuse and regulatory problems. Emerging microbes, resistance...
Antibiotics' usefulness is threatened by multi-drugs resistance in harmful microorganisms because of abuse and regulatory problems. Emerging microbes, resistance mechanisms and antimicrobial drugs all require extensive investigation. Evaluation of the in vitro antibacterial activity of Methanolic extracts isolated from Black pepper seeds (Piper nigrum L.) against two infection causing pathogens, Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa. From July 2022 and June 2023, this experimental study was conducted at the Mymensingh Medical College's Department of Pharmacology and Therapeutics in conjunction with the Department of Microbiology. The solvents Methanol and 10.0% Di-Methyl Sulfoxide (DMSO) were used to make the extract. Using the disc diffusion and broth dilution methods, the antibacterial activity of methanolic extract of black pepper seeds (MBPE) was evaluated at various doses. Using the broth dilution procedure, the conventional antibiotic Ciprofloxacin was utilized, and the outcome was contrasted with that of Methanol extracts. Methanolic extract of black pepper seeds (MBPE) at seven distinct concentrations (100, 80, 60, 40, 20, 10 and 5mg/ml) were utilized, then later in chosen concentrations as needed to confirm the extracts' more precise margin of antimicrobial sensitivity. At 80mg/ml and above doses of the MBPE, it had an inhibitory impact against the aforementioned microorganisms. For Staphylococcus aureus and Pseudomonas aeruginosa the MIC were 60 and 70mg/ml in MBPE respectively. As of the MIC of Ciprofloxacin was 1μg/ml against Staphylococcus aureus and 1.5μg/ml for Pseudomonas aeruginosa. In comparison to MICs of MBPE for the test organisms, the MIC of Ciprofloxacin was the lowest. This study clearly shows that Staphylococcus aureus and Pseudomonas aeruginosa are sensitive to the methanolic extract of black pepper seeds' antibacterial properties.
Topics: Piper nigrum; Pseudomonas aeruginosa; Plant Extracts; Staphylococcus aureus; Seeds; Anti-Bacterial Agents; Microbial Sensitivity Tests; Methanol
PubMed: 38944702
DOI: No ID Found -
Quantification of early biofilm growth in microtiter plates through a novel image analysis software.Journal of Microbiological Methods Jun 2024Given the significant impact of biofilms on human health and material corrosion, research in this field urgently needs more accessible techniques to facilitate the...
Given the significant impact of biofilms on human health and material corrosion, research in this field urgently needs more accessible techniques to facilitate the testing of new control agents and general understanding of biofilm biology. Microtiter plates offer a convenient format for standardized evaluations, including high-throughput assays of alternative treatments and molecular modulators. This study introduces a novel Biofilm Analysis Software (BAS) for quantifying biofilms from microtiter plate images. We focused on early biofilm growth stages and compared BAS quantification to common techniques: direct turbidity measurement, intrinsic fluorescence detection linked to pyoverdine production, and standard crystal violet staining which enables image analysis and optical density measurement. We also assessed their sensitivity for detecting subtle growth effects caused by cyclic AMP and gentamicin. Our results show that BAS image analysis is at least as sensitive as the standard method of spectrophotometrically quantifying the crystal violet retained by biofilms. Furthermore, we demonstrated that bacteria adhered after short incubations (from 10 min to 4 h), isolated from planktonic populations by a simple rinse, can be monitored until their growth is detectable by intrinsic fluorescence, BAS analysis, or resolubilized crystal violet. These procedures are widely accessible for many laboratories, including those with limited resources, as they do not require a spectrophotometer or other specialized equipment.
PubMed: 38944284
DOI: 10.1016/j.mimet.2024.106979 -
Microbes and Infection Jun 2024Antimicrobial treatment of methicillin-resistant Staphylococcus pseudintermedius associated with canine wounds represents an important challenge. The aim of this study...
Antimicrobial treatment of methicillin-resistant Staphylococcus pseudintermedius associated with canine wounds represents an important challenge. The aim of this study was to create a canine wound infection model, Lubbock Chronic Wound Biofilm (LCWB), with a focus on S. pseudintermedius, drawing inspiration from the established human model involving S. aureus. Methicillin-resistant S. pseudintermedius 115 (MRSP) and Pseudomonas aeruginosa 700 strains, isolated from dog wounds, were used to set up the LCWB at 24, 48 and 72h. The LCWBs were evaluated in terms of volume, weight, and microbial CFU/mg. The microbial spatial distribution in the LCWBs was assessed by SEM and CLSM imaging. The best incubation time for the LCWB production in terms of volume (3.38 cm ± 0.13), weight (0.86 gr ± 0.02) and CFU/mg (up to 7.05 x 10 CFU/mg ± 2.89 x 10) was 48h. The SEM and CLSM images showed a major viable microbial colonization at 48h with a non-mixed bacteria with a prevalence of MRSP on the surface and P. aeruginosa 700 in the depth of the wound. The obtained findings demonstrate the capability of S. pseudintermedius to grow together P. aeruginosa in the LCWB model, representing the suitable model to reproduce the animal chronic wound in vitro.
PubMed: 38944110
DOI: 10.1016/j.micinf.2024.105384 -
Auris, Nasus, Larynx Jun 2024Knowledge about voice prosthesis microbial colonization is vital in laryngectomized patients' quality of life (QoL). Herein, we aimed to explore the relationship between...
OBJECTIVE
Knowledge about voice prosthesis microbial colonization is vital in laryngectomized patients' quality of life (QoL). Herein, we aimed to explore the relationship between oral microbial patterns, demographic variables and voice prosthesis performance.
METHODS
Thirty laryngectomy patients were assessed for microbial colonization in their voice prostheses and oral cavities. Factors like age, proton pump inhibitor (PPI) usage, and alcohol consumption were considered.
RESULTS
Participants' average age was 74.20 ± 7.31 years, with a majority on PPIs. Staphylococcus aureus was the most common bacterium in prostheses (53 %), followed by Pseudomonas aeruginosa (27 %). Candida albicans was the primary fungal colonizer (67 %). A statistically significant moderate correlation was found between fungal species before and after oral rinsing (p = 0.035, Phi=0.588, Cramer's V = 0.416). Voice prosthesis and oral cavity microbiota profiles showed significant concordance (kappa=0.315, p < 0.004). Among subgroup analyses, bacterial patterns of colonization did not significantly influence VHI (p = 0.9555), VrQoL (p = 0.6610), or SF-36 (p = 0.509) scores. Conversely, fungal patterns of VP colonization significantly impacted subjective voice scores, with Candida krusei demonstrating better VHI (35.25 ± 3.63 vs. 44.54 ± 6.33; p = 0.008), VrQoL (7.13 ± 1.69 vs. 10.73 ± 2.00; p = 0.001), and SF-36 (69.36 ± 7.09 vs. 76.50 ± 7.73; p = 0.051) scores compared to C. albicans.
CONCLUSIONS
There was a significant correlation between the oral microbiota and voice prosthesis colonization. These insights can inform improved care strategies for voice prostheses, enhancing patient outcomes.
PubMed: 38943902
DOI: 10.1016/j.anl.2024.06.006 -
BMC Oral Health Jun 2024Tissue conditioners are used for treating and improving the tissues supporting complete dentures. On the other hand, recent advances in nanotechnology have...
BACKGROUND
Tissue conditioners are used for treating and improving the tissues supporting complete dentures. On the other hand, recent advances in nanotechnology have revolutionized various fields of science, including dentistry. The present study aimed to investigate novel antimicrobial applications of copper oxide nanoparticle-based tissue conditioner used in complete prostheses.
METHODS
The present experimental study included 126 tissue conditioner samples with different concentrations of copper oxide nanoparticles (20%, 10%, 5%, 2.5%, 1.25%, 0.625%, and 0% w/w). The samples were incubated with Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans in 24-well plates for 24 h. Then, samples from the wells were re-incubated for 24 h, and the microorganisms were counted.
RESULTS
The culture media containing E. faecalis and P. aeruginosa showed significantly different growth between different nanoparticle concentrations following 24 h (P < 0.001), showing a reduction in bacterial growth with increased nanoparticle concentration. Both bacteria did not show any growth at the 20% concentration. However, C. albicans showed significant differences in growth between different nanoparticle concentrations following 48 h (P < 0.001), showing a reduction in growth with increased nanoparticle concentration. Also, the least growth was observed at the 20% concentration.
CONCLUSIONS
In conclusion, the CuO nanoparticles were prepared using a green synthesis methon in the suitable sizes. Moreover, the tissue conditioners containing CuO nanoparticles showed acceptable antimicrobial properties against E. faecalis, P. aeruginosa, and C. albicans.
Topics: Copper; Enterococcus faecalis; Candida albicans; Pseudomonas aeruginosa; Anti-Infective Agents; Denture, Complete; Nanoparticles; Humans; Metal Nanoparticles
PubMed: 38943115
DOI: 10.1186/s12903-024-04534-w -
Molecular Imaging and Biology Jun 2024There is currently no ideal radiotracer for imaging bacterial infections. Radiolabelled D-amino acids are promising candidates because they are actively incorporated...
PURPOSE
There is currently no ideal radiotracer for imaging bacterial infections. Radiolabelled D-amino acids are promising candidates because they are actively incorporated into the peptidoglycan of the bacterial cell wall, a structural feature which is absent in human cells. This work describes fluorine-18 labelled analogues of D-tyrosine and D-methionine, O-(2-[F]fluoroethyl)-D-tyrosine (D-[F]FET) and S-(3-[F]fluoropropyl)-D-homocysteine (D-[F]FPHCys), and their pilot evaluation studies as potential radiotracers for imaging bacterial infection.
PROCEDURES
D-[F]FET and D-[F]FPHCys were prepared in classical fluorination-deprotection reactions, and their uptake in Staphylococcus aureus and Pseudomonas aeruginosa was evaluated over 2 h. Heat killed bacteria were used as controls. A clinically-relevant foreign body model of S. aureus infection was established in Balb/c mice, as well as a sterile foreign body to mimic inflammation. The ex vivo biodistribution of D-[F]FPHCys in the infected and inflamed mice was evaluated after 1 h, by dissection and gamma counting. The uptake was compared to that of [F]FDG.
RESULTS
In vitro uptake of both D-[F]FET and D-[F]FPHCys was specific to live bacteria. Uptake was higher in S. aureus than in P. aeruginosa for both radiotracers, and of the two, higher for D-[F]FPHCys than D-[F]FET. Blocking experiments with non-radioactive D-[F]FPHCys confirmed specificity of uptake. In vivo, D-[F]FPHCys had greater accumulation in S. aureus infection compared with sterile inflammation, which was statistically significant. As anticipated, [F]FDG showed no significant difference in uptake between infection and inflammation.
CONCLUSIONS
D-[F]FPHCys uptake was higher in infected tissues than inflammation, and represents a fluorine-18 labelled D-AA with potential to detect a S. aureus reference strain (Xen29) in vivo. Additional studies are needed to evaluate uptake of this radiotracer in clinical isolates.
PubMed: 38942967
DOI: 10.1007/s11307-024-01929-7