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Nano-ciprofloxacin/meropenem exhibit bactericidal activity against Gram-negative bacteria and rescue septic rat model.

Aim: We hypothesized that simultaneous administration of two antibiotics loaded into a nanopolymer matrix would augment their synergistic bactericidal interaction. Methods: Nanoplatforms of chitosan/Pluronic® loaded with ciprofloxacin/meropenem (CS/Plu-Cip/Mer) were prepared by the ionic gelation method, using Plu at concentrations in the range 0.5-4% w/v. CS/Plu-Cip/Mer was evaluated for antibacterial synergistic activity in vitro and in vivo. Results: CS/Plu-Cip and CS/Plu-Mer with Plu concentrations of 3% w/v and 2% w/v, respectively, exhibited ∼80% encapsulation efficiency. The MICs of pat

Multicenter Surveillance of Antimicrobial Resistance among Gram-Negative Bacteria Isolated from Bloodstream Infections in Ghana.

BACKGROUND: Antimicrobial resistance (AMR) in Gram-negative bacteria-causing bloodstream infections (BSIs), such as Klebsiella pneumoniae and non-typhoidal Salmonella (NTS), is a major public health concern. Nonetheless, AMR surveillance remains scarce in sub-Saharan Africa, where BSI treatment is largely empirical. The aim of the study was to determine the distribution and AMR patterns of BSI-causing NTS, K. pneumoniae, and other Gram-negative bacteria in Ghana. METHODS: A cross-sectional study was conducted between April and December 2021 at eleven sentinel health facilities across Ghana as…

Antibiotic-Resistant Gram-negative Bacteria Carriage in Healthcare Workers Working in an Intensive Care Unit.

Little is known about antibiotic-resistant Gram-negative bacteria (GNB) intestinal carriage among healthcare workers (HCWs) in Vietnam. All HCWs at a tertiary intensive care units were asked to undertake weekly rectal swabs. Among 40 participants, 65% (26/40) carried extended spectrum β-lactamases (ESBL)/AmpC β-lactamase-producing Escherichia coli. Two HCWs colonized with ESBL/AmpC β-lactamase-producing Klebsiella pneumoniae. One HCW colonized with Acinetobacter baumannii. No one carried Pseudomonas spp.. A quarter (10/40) of HCWs were identified as persistent and frequent carriers. There is a…

Developing Cyclic Peptomers as Broad-Spectrum Type III Secretion System Inhibitors in Gram-Negative Bacteria.

Antibiotic-resistant bacteria are an emerging global health threat. New antimicrobials are urgently needed. The injectisome type III secretion system (T3SS), required by dozens of Gram-negative bacteria for virulence but largely absent from nonpathogenic bacteria, is an attractive antimicrobial target. We previously identified synthetic cyclic peptomers, inspired by the natural product phepropeptin D, that inhibit protein secretion through the Yersinia Ysc and Pseudomonas aeruginosa Psc T3SSs but do not inhibit bacterial growth. Here, we describe the identification of an isomer, 4EpDN, that is…

Multidrug-Resistant Gram-Negative Bacteria Decolonization in Immunocompromised Patients: A Focus on Fecal Microbiota Transplantation.

Antimicrobial resistance is an important issue for global health; in immunocompromised patients, such as solid organ and hematological transplant recipients, it poses an even bigger threat. Colonization by multidrug-resistant (MDR) bacteria was acknowledged as a strong risk factor to subsequent infections, especially in individuals with a compromised immune system. A growing pile of studies has linked the imbalance caused by the dominance of certain taxa populating the gut, also known as intestinal microbiota dysbiosis, to an increased risk of MDR bacteria colonization. Several attempts were p

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… In this review, we focused on MDR gram-negative bacteria (MDR-GNB) because of their significance in immunocompromised patients, and explored the strategies and management methods used to address the issue of colonization and subsequent infection. … Intestinal domination by Gram-negative bacteria, defined as occupation of at least 30% of the microbiota by a single predominating bacterial taxon, is relatively common. …

Discovery of Novel Inhibitors of LpxC Displaying Potent in Vitro Activity against Gram-Negative Bacteria.

UDP-3-O-((R)-3-hydroxymyristoyl)-N-glucosamine deacetylase (LpxC) is as an attractive target for the discovery and development of novel antibacterial drugs to address the critical medical need created by multidrug resistant Gram-negative bacteria. By using a scaffold hopping approach on a known family of methylsulfone hydroxamate LpxC inhibitors, several hit series eliciting potent antibacterial activities against Enterobacteriaceae and Pseudomonas aeruginosa were identified. Subsequent hit-to-lead optimization, using cocrystal structures of inhibitors bound to Pseudomonas aeruginosa LpxC as g…

Lactococcus Lactis Strain A5 Producing Nisin-like Bacteriocin Active against Gram Positive and Negative Bacteria.

In this study, a Lactic acid bacteria (LAB) strain was isolated on MRS medium from gastro-intestinal tissues of Broadhead catfish (Clarias macrocephalus). Out of 50 isolates, 25 isolates were found to be positive on lactose utilisation test and were identified to be gram positive cocci. Using disc diffusion methods, one out of 22 isolates, i.e., a strain A5 demonstrated inhibitions against three indicator organisms; Bacillus cereus, Staphylococcus aureus and Salmonella thyphimurium. Partial 16S rDNA sequencing identified isolate A5 as a member of Lactococcus lactis, with 100% DNA homology. Cel

Low antibiotic resistance among anaerobic Gram-negative bacteria in periodontitis 5 years following metronidazole therapy.

The objective of this study was to assess antibiotic susceptibility among predominant Gram-negative anaerobic bacteria isolated from periodontitis patients who 5 years prior had been subject to mechanical therapy with or without adjunctive metronidazole. One pooled sample was taken from the 5 deepest sites of each of 161 patients that completed the 5 year follow-up after therapy. The samples were analyzed by culture. A total number of 85 anaerobic strains were isolated from the predominant subgingival flora of 65/161 patient samples, identified, and tested for antibiotic susceptibility by MIC

Antimicrobial susceptibility of Gram-negative bacteria causing intra-abdominal infections in China: SMART China 2011.

BACKGROUND: The Study for Monitoring Antimicrobial Resistance Trends program monitors the activity of antibiotics against aerobic and facultative Gram-negative bacilli (GNBs) from intra-abdominal infections (IAIs) in patients worldwide. METHODS: In 2011, 1 929 aerobic and facultative GNBs from 21 hospitals in 16 cities in China were collected. All isolates were tested using a panel of 12 antimicrobial agents, and susceptibility was determined following the Clinical Laboratory Standards Institute guidelines. RESULTS: Among the Gram-negative pathogens causing IAIs, Escherichia coli (47.3%) was

Doxycycline interferes with quorum sensing-mediated virulence factors and biofilm formation in gram-negative bacteria.

Inhibition of quorum sensing (QS)-regulated virulence factors including biofilm is a recognized anti-pathogenic drug target. The search for safe and effective anti-QS agents is expected to be useful to combat diseases caused by multidrug-resistant bacteria. In this study, effect of a commonly used antibiotic, doxycycline on QS was evaluated using sensor strains of Chromobacterium violaceum (ATCC 12472 and CVO26) and Pseudomonas aeruginosa PAO1. Sub-MICs of doxycycline reduced QS-controlled violacein production in C. violaceum to a significant degree (70 %) and showed a significant reduction of

Reversible IgA deficiency after severe Gram-negative bacteria infection in a patient with systemic sclerosis.

A 43-year-old woman with systemic sclerosis (SSc) developed IgA deficiency (IgAD) after cholecystitis. The severe decrease of IgA (<10 mg/dl) partially recovered after 5 years. She had repeated episodes of infection during IgAD. Anti-IgA antibody was not detected. Flow cytometric analysis showed that peripheral CD19(+)IgA(+) and CD38(+)IgA(+) cells were normally present. Although the mechanism of secondary IgAD is still vague, its association with autoimmune diseases including SSc and also with bacterial infection is discussed.

The cyclotide cycloviolacin O2 from Viola odorata has potent bactericidal activity against Gram-negative bacteria.

OBJECTIVES: To determine the antibacterial activity of small cyclic plant proteins, i.e. cyclotides, and the importance of the surface expos … less pronounced activity reduction. CONCLUSIONS: CyO2 is a cyclotide with potent activity against Gram-negative bacteria. The charged residues in cyO2 are all required for optimum antibacterial activity. In combination with its previously demonstrated cytotoxic activity against cancer cells and the general stability of cyclotides, cyO2 provides a promising scaffold fo …

Multiantibiotic resistance caused by active drug extrusion in Pseudomonas aeruginosa and other gram-negative bacteria.

All living organisms have been exposed to noxious compounds throughout their long evolutionary history and those surviving have evolved to fabricate devices that detoxicate and extrude these life threatening substances. It is likely, therefore, that all viable organisms, from bacteria to mammals, are equipped with active extrusion machinery. When bacteria are attacked by antibiotics, they use these tactics to combat the drugs and to develop resistance. Drugs extrusion machinery in Gram-negative bacteria is complex, consisting of the inner membrane transporter which acts as an energy-dependent …

National Committee for Clinical Laboratory Standards agar dilution susceptibility testing of anaerobic gram-negative bacteria.

One hundred nine recent clinical isolates of anaerobic gram-negative bacteria were tested in triplicate by the National Committee for Clinical Laboratory Standards agar dilution procedure for their susceptibility to 32 antimicrobial agents. All isolates were inhibited by imipenem, but there were significant numbers of strains resistant to other beta-lactam drugs, and therefore the in vitro response to these antimicrobial agents cannot be predicted. This was particularly true for the bile-resistant or Bacteroides fragilis group. beta-Lactamase production was detected in 82% of the bacteroides w…

Permeation of beta-lactam antibiotics into Escherichia coli, Pseudomonas aeruginosa, and other gram-negative bacteria.

Cell wall impermeability is a major determinant of the susceptibility of gram-negative bacilli to beta-lactam antibiotics. The outer membrane, which beta-lactam agents cross via pores composed of porin proteins, is the major individual barrier in the wall structure but does not of itself exclude these antibiotics. Rather, it slows their influx to a level that the periplasmic clearance mechanisms may manage to contain. The clearance mechanisms include hydrolysis and perhaps covalent binding by beta-lactamases and nonessential penicillin-binding proteins. The balance between uptake and clearance

Pyridine-containing iridium complexes as gram-negative bacteria specific therapeutic agents with low resistance development.

The propensity of antibiotics to provoke drug resistance in clinical applications, along with their low selectivity, has collectively contri … t causing significant tissue damage, highlighting its potential as a therapeutic agent for treating Gram-negative bacterial infections.

Potentiating Gentamicin Efficacy Against Biofilms of Clinically Relevant Gram-Negative Bacteria Using Biosynthesized ZnO Nanoparticles.

Background: Gram-negative bacteria resistant to multiple drugs are a major cause of illness and death worldwide. Their remarkable capacity to develop resistance to antibiotics makes them a serious concern in medical practice. Methods: A simple, green, novel method is used to synthesize ZnO nanoparticles (ZnO NPs) using ethanolic extracts of Diplazium esculentum via precipitation. Results: ZnO NPs exhibit a hexagonal structure with a particle size of ~30 nm and a band gap of 3.24 eV. The defect sites formed in ZnO NPs were estimated using prominent peaks in the photoluminescence spectra. ZnO NP…

Antimicrobial and probiotic potential of Lactobacillus from traditional dairy products against uropathogenic gram-negative bacteria.

Urinary tract infections (UTIs) are among the most prevalent bacterial infections and are increasingly complicated by the emergence of multidrug-resistant uropathogens. The present study investigated the probiotic potential and anti-uropathogenic activity of Lactobacillus strains isolated from traditional dairy products in western Algeria using combined in vitro screening and an in vivo rat model of UTI. Uropathogenic bacteria recovered from urine samples of female patients were identified as Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Proteus vulgaris using standard microb

Thymidylate Kinase-Targeted Antimicrobial Peptides via Phage Display: A Novel Strategy against Gram-Negative Bacteria.

The rise of antimicrobial resistance (AMR) in Gram-negative bacteria, including Escherichia coli (E. coli), poses a major public health threat. This study aimed to address the limitations of existing antimicrobial peptides (AMPs) by designing hybrid peptides with enhanced targeting and antibacterial potency. Eight heptapeptide sequences were identified through phage display screening and hybridized with WP (WKKIWKPGIKKWIK), a peptide exhibiting weak antimicrobial activity against Gram-negative bacteria. The hybrid peptides were systematically evaluated for their antimicrobial activity, specifi…

Surveillance of Multidrug-Resistant Genes in Clinically Significant Gram-Negative Bacteria Isolated from Hospital Wastewater.

BACKGROUND/OBJECTIVES: Antimicrobial resistance (AMR) has become a serious public health threat worldwide. Among the various surveillance domains, hospital wastewater (HWW) has been overlooked, and it is the major reason for the threats posed by AMR. Therefore, the HWW domain is of paramount importance for tackling the AMR. In this regard, the present study investigated the occurrence of Gram-negative bacteria from HWW and evaluated the isolates' multi-drug-resistant (MDR) pattern in the study environment. METHODS: This descriptive study involves HWW samples (n = 24) consecutively collected a…