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Microorganisms May 2024aeruginosa is a pathogen that causes healthcare-associated infections (HAIs) worldwide. It is unclear whether isolated from the natural environment has the same...
aeruginosa is a pathogen that causes healthcare-associated infections (HAIs) worldwide. It is unclear whether isolated from the natural environment has the same pathogenicity and antimicrobial resistance potential as clinical strains. In this study, virulence- and resistance-associated genes were compared in 14 genomic sequences of clinical and environmental isolates of using the VFDB, PATRIC, and CARD databases. All isolates were found to share 62% of virulence genes related to adhesion, motility, secretion systems, and quorum sensing and 72.9% of resistance genes related to efflux pumps and membrane permeability. Our results indicate that both types of isolates possess conserved genetic information associated with virulence and resistance mechanisms regardless of the source. However, none of the environmental isolates were associated with high-risk clones (HRCs). These clones (ST235 and ST111) were found only in clinical isolates, which have an impact on human medical epidemiology due to their ability to spread and persist, indicating a correlation between the clinical environment and increased virulence. The genomic variation and antibiotic susceptibility of environmental isolates of suggest potential biotechnological applications if obtained from sources that are under surveillance and investigation to limit the emergence and spread of antibiotic resistant strains.
PubMed: 38930498
DOI: 10.3390/microorganisms12061116 -
Antioxidants (Basel, Switzerland) May 2024() is an opportunistic pathogen frequently isolated from cutaneous chronic wounds. How , in the presence of oxidative stress (OS), colonizes chronic wounds and forms a...
() is an opportunistic pathogen frequently isolated from cutaneous chronic wounds. How , in the presence of oxidative stress (OS), colonizes chronic wounds and forms a biofilm is still unknown. The purpose of this study is to investigate the changes in gene expression seen when PA is challenged with the high levels of OS present in chronic wounds. We used a biofilm-forming strain isolated from the chronic wounds of our murine model (RPA) and performed a qPCR to obtain gene expression patterns as RPA developed a biofilm in vitro in the presence of high levels of OS, and then compared the findings in vivo, in our mouse model of chronic wounds. We found that the planktonic bacteria under OS conditions overexpressed quorum sensing genes that are important for the bacteria to communicate with each other, antioxidant stress genes important to reduce OS in the microenvironment for survival, biofilm formation genes and virulence genes. Additionally, we performed RNAseq in vivo and identified the activation of novel genes/pathways of the Type VI Secretion System (T6SS) involved in RPA pathogenicity. In conclusion, RPA appears to survive the high OS microenvironment in chronic wounds and colonizes these wounds by turning on virulence, biofilm-forming and survival genes. These findings reveal pathways that may be promising targets for new therapies aimed at disrupting -containing biofilms immediately after debridement to facilitate the treatment of chronic human wounds.
PubMed: 38929094
DOI: 10.3390/antiox13060655 -
International Journal of Environmental... May 2024The effects of exposure to airborne particulate matter with a size of 10 μm or less (PM) on C57BL/6 mouse corneas, their response to (PA) infection, and the protective...
The effects of exposure to airborne particulate matter with a size of 10 μm or less (PM) on C57BL/6 mouse corneas, their response to (PA) infection, and the protective effects of SKQ1 were determined. C57BL/6 mouse corneas receiving PBS or SKQ1 were exposed to control (air) or PM for 2 weeks, infected, and the disease was documented by clinical score, PMN quantitation, bacterial plate count, RT-PCR and Western blot. PBS-treated, PM-exposed corneas did not differ at 1 day postinfection (dpi), but exhibited earlier (3 dpi) corneal thinning compared to controls. By 3 dpi, PM significantly increased corneal mRNA levels of several pro-inflammatory cytokines, but decreased IL-10, NQO1, GR1, GPX4, and Nrf2 over control. SKQ1 reversed these effects and Western blot selectively confirmed the RT-PCR results. PM resulted in higher viable bacterial plate counts at 1 and 3 dpi, but SKQ1 reduced them at 3 dpi. PM significantly increased MPO in the cornea at 3 dpi and was reduced by SKQ1. SKQ1, used as an adjunctive treatment to moxifloxacin, was not significantly different from moxifloxacin alone. Exposure to PM increased the susceptibility of C57BL/6 to PA infection; SKQ1 significantly reversed these effects, but was not effective as an adjunctive treatment.
Topics: Animals; Mice, Inbred C57BL; Pseudomonas Infections; Particulate Matter; Pseudomonas aeruginosa; Mice; Cornea; Disease Susceptibility; Cytokines; Female; Air Pollutants
PubMed: 38928968
DOI: 10.3390/ijerph21060722 -
International Journal of Molecular... Jun 2024This paper presents the work performed to transition a lab-scale synthesis (1 g) to a large-scale (400 g) synthesis of the 3-5-diamino-1H-Pyrazole Disperazol, a new...
This paper presents the work performed to transition a lab-scale synthesis (1 g) to a large-scale (400 g) synthesis of the 3-5-diamino-1H-Pyrazole Disperazol, a new pharmaceutical for treatment of antibiotic-resistant biofilm infections. The potentially hazardous diazotisation step in the lab-scale synthesis was transformed to a safe and easy-to-handle flow chemistry step. Additionally, the paper presents an OSHA-recommended safety assessment of active compound , as performed by Fauske and Associates, LLC, Burr Ridge, IL, USA.
Topics: Pyrazoles; Pseudomonas aeruginosa; Anti-Bacterial Agents; Biofilms; Humans; Pseudomonas Infections; Risk Assessment
PubMed: 38928443
DOI: 10.3390/ijms25126737 -
Genes Jun 2024Many enzymes in the Raetz pathway for lipid A biosynthesis in are essential. A homologous protein Pa1792|LpxH in is known to complement the loss of LpxH in ....
Many enzymes in the Raetz pathway for lipid A biosynthesis in are essential. A homologous protein Pa1792|LpxH in is known to complement the loss of LpxH in . Genome-wide transposon-insertion sequencing analysis indicates that is essential in . However, genetic analysis of in has not been carried out, partly because the conditional alleles of essential genes are not readily constructed. In this study, we first constructed a plasmid-based temperature-sensitive mutant or in PAO1. Spot-plating assay indicated that was lethal at a restrictive temperature, confirming its essentiality for growth. Microscopic analysis revealed that exhibited an oval-shaped morphology, suggesting that was required for rod-shape formation. SDS-PAGE and Western blotting analysis showed that failed to synthesize lipid A, consistent with its function in lipid A biosynthesis. Strong expression of but not the non-homologous isoenzyme or impeded growth and caused cell lysis, implying that -specific cofactors were required for this toxic effect in . Together, our results demonstrate that is essential for lipid A biosynthesis, rod-shaped growth, and viability in . We propose that this plasmid-based conditional allele is a useful tool for the genetic study of essential genes in .
Topics: Pseudomonas aeruginosa; Plasmids; Bacterial Proteins; Temperature; Mutation; Lipid A; Escherichia coli
PubMed: 38927720
DOI: 10.3390/genes15060784 -
Biology May 2024Compared to pathogens and , HYS has stronger virulence towards . However, the underlying mechanisms haven't been fully understood. The heme synthesis system is...
Compared to pathogens and , HYS has stronger virulence towards . However, the underlying mechanisms haven't been fully understood. The heme synthesis system is essential for virulence, and former studies of HemN have focused on the synthesis of heme, while the relationship between HemN and virulence were barely pursued. In this study, we hypothesized that deficiency affected 7-hydroxytropolone (7-HT) biosynthesis and redox levels, thereby reducing bacterial virulence. There are four genes in HYS, and we reported for the first time that deletion of significantly reduced the virulence of HYS towards , whereas the reduction in virulence by the other three genes was not significant. Interestingly, deletion significantly reduced colonization of HYS in the gut of . Further studies showed that HemN2 was regulated by GacS and participated in the virulence of HYS towards by mediating the synthesis of the virulence factor 7-HT. In addition, HemN2 and GacS regulated the virulence of HYS by affecting antioxidant capacity and nitrative stress. In short, the findings that HemN2 was regulated by the Gac system and that it was involved in bacterial virulence via regulating 7-HT synthesis and redox levels were reported for the first time. These insights may enlighten further understanding of HemN-based virulence in the genus .
PubMed: 38927253
DOI: 10.3390/biology13060373 -
Antibiotics (Basel, Switzerland) Jun 2024We evaluated the activities of aztreonam/avibactam and recently approved β-lactamase inhibitor combinations (BLICs) to compare the antimicrobial susceptibility patterns...
Activity of Aztreonam/Avibactam and Recently Approved β-Lactamase Inhibitor Combinations against Enterobacterales and from Intensive Care Unit and Non-Intensive Care Unit Patients.
We evaluated the activities of aztreonam/avibactam and recently approved β-lactamase inhibitor combinations (BLICs) to compare the antimicrobial susceptibility patterns of Enterobacterales and isolated from intensive care unit (ICU) and non-ICU patients. Clinical isolates (1/patient) were consecutively collected from 72 United States medical centres in 2020-2022 and susceptibility tested by broth microdilution. The results for 5421 isolates from ICU patients were analysed and compared to those for 20,649 isolates from non-ICU patients. Isolates from ventilator-associated pneumonia patients were analysed separately. Aztreonam/avibactam inhibited 100.0%/>99.9% Enterobacterales and 100.0%/98.3% of carbapenem-resistant Enterobacterales (CRE) from ICU/non-ICU patients at ≤8 mg/L, respectively. The CRE susceptibility rates were 88.5%/82.9% for ceftazidime/avibactam, 82.1%/81.2% for meropenem/vaborbactam, and 78.2%/72.6% for imipenem/relebactam among ICU/non-ICU isolates. Among the isolates from ICU/non-ICU patients, the susceptibility rates were 96.3%/97.6% for ceftazidime/avibactam, 97.2/98.4% for ceftolozane/tazobactam, 97.1%/98.0% for imipenem/relebactam, 77.8%/84.6% for piperacillin/tazobactam, and 76.9%/85.8% for meropenem; aztreonam/avibactam inhibited 78.0%/81.9% of at ≤8 mg/L. In summary, lower susceptibility rates were observed among ICU than non-ICU isolates. Aztreonam/avibactam exhibited potent in vitro activity and broad-spectrum activity against Enterobacterales from ICU and non-ICU patients, including CRE and isolates non-susceptible to newer BLICs. Against , aztreonam/avibactam showed a spectrum of activity comparable to that of piperacillin/tazobactam, meropenem, and ceftazidime.
PubMed: 38927230
DOI: 10.3390/antibiotics13060564 -
Antibiotics (Basel, Switzerland) Jun 2024Carbapenemases, a class of enzymes specialized in the hydrolysis of carbapenems, represent a significant threat to global public health. These enzymes are classified... (Review)
Review
Carbapenemases, a class of enzymes specialized in the hydrolysis of carbapenems, represent a significant threat to global public health. These enzymes are classified into different Ambler's classes based on their active sites, categorized into classes A, D, and B. Among the most prevalent types are IMI/NMC-A, KPC, VIM, IMP, and OXA-48, commonly associated with pathogenic species such as , , and . The emergence and dissemination of carbapenemase-producing bacteria have raised substantial concerns due to their ability to infect humans and animals (both companion and food-producing) and their presence in environmental reservoirs. Adopting a holistic One Health approach, concerted efforts have been directed toward devising comprehensive strategies to mitigate the impact of antimicrobial resistance dissemination. This entails collaborative interventions, highlighting proactive measures by global organizations like the World Health Organization, the Center for Disease Control and Prevention, and the Food and Agriculture Organization. By synthesizing the evolving landscape of carbapenemase epidemiology in Portugal and tracing the trajectory from initial isolated cases to contemporary reports, this review highlights key factors driving antibiotic resistance, such as antimicrobial use and healthcare practices, and underscores the imperative for sustained vigilance, interdisciplinary collaboration, and innovative interventions to curb the escalating threat posed by antibiotic-resistant pathogens. Finally, it discusses potential alternatives and innovations aimed at tackling carbapenemase-mediated antibiotic resistance, including new therapies, enhanced surveillance, and public awareness campaigns.
PubMed: 38927223
DOI: 10.3390/antibiotics13060557 -
Antibiotics (Basel, Switzerland) Jun 2024The Infectious Diseases Society of America (IDSA) recommends a single dose of an aminoglycoside for uncomplicated cystitis caused by extended-spectrum beta-lactamase...
The Infectious Diseases Society of America (IDSA) recommends a single dose of an aminoglycoside for uncomplicated cystitis caused by extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales (ESBL-E) and difficult-to-treat . However, there is very little recent clinical evidence to support this recommendation. The objective of this study was to evaluate the safety and efficacy of a single-dose aminoglycoside for cystitis caused by ESBL-E or . This was a multicenter, retrospective, cohort study. Patients who received ≥3 days of standard of care were compared to patients who received a one-time dose of an aminoglycoside with or without a short course of effective therapy before. The primary outcome was the rate of relapse defined as requiring escalation of antibiotics or starting new antibiotic therapy within 14 days after the completion of antibiotics. A total of 66 patients were included in this study, with 33 patients in each arm. There were more males and complicated cystitis patients in the standard-of-care group. There was no difference found in the rate of relapse. The length of stay was significantly shorter in the aminoglycoside group (4.5 ± 4.4 days vs. 14.1 ± 10.1 days, < 0.0001). A one-time dose of an aminoglycoside did not increase the risk of relapse and was associated with a shorter length of stay when used to treat cystitis caused by ESBL-E or .
PubMed: 38927218
DOI: 10.3390/antibiotics13060552 -
Antibiotics (Basel, Switzerland) Jun 2024The prevalence of carbapenem-resistant has dramatically increased over the last decade, and antibiotics alone are not enough to eradicate infections caused by this...
The prevalence of carbapenem-resistant has dramatically increased over the last decade, and antibiotics alone are not enough to eradicate infections caused by this opportunistic pathogen. Phage therapy is a fresh treatment that can be administered under compassionate use, particularly against chronic cases. However, it is necessary to thoroughly characterize the virus before therapeutic application. Our work describes the discovery of the novel sequenced bacteriophage, vB_PaeP-F1Pa, containing an integrase, performs a phylogenetical analysis, describes its stability at a physiological pH and temperature, latent period (40 min), and burst size (394 ± 166 particles per bacterial cell), and demonstrates its ability to infect MDR and XDR strains. Moreover, this novel bacteriophage was able to inhibit the growth of bacteria inside preformed biofilms. The present study offers a road map to analyze essential areas for successful phage therapy against MDR and XDR infections, and shows that a phage containing an integrase is also able to show good in vitro results, indicating that it is very important to perform a genomic analysis before any clinical use, in order to prevent adverse effects in patients.
PubMed: 38927189
DOI: 10.3390/antibiotics13060523