scholarly journals Antimicrobial Activity of Aztreonam in Combination with Old and New β-Lactamase Inhibitors against MBL and ESBL Co-Producing Gram-Negative Clinical Isolates: Possible Options for the Treatment of Complicated Infections

Antibiotics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1341
Author(s):  
Gianluca Morroni ◽  
Raffaela Bressan ◽  
Simona Fioriti ◽  
Gloria D’Achille ◽  
Marina Mingoia ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Resistance Mechanisms ◽  
Clinical Isolates ◽  
Active Therapy ◽  
Gram Negative ◽  
Effective Combination ◽  
Fold Reduction ◽  
Additional Resistance ◽  
Kill Curve ◽  
Time Kill

Metallo-β-lactamases (MBLs) are among the most challenging bacterial enzymes to overcome. Aztreonam (ATM) is the only β-lactam not hydrolyzed by MBLs but is often inactivated by co-produced extended-spectrum β-lactamases (ESBL). We assessed the activity of the combination of ATM with old and new β-lactamases inhibitors (BLIs) against MBL and ESBL co-producing Gram-negative clinical isolates. Six Enterobacterales and three non-fermenting bacilli co-producing MBL and ESBL determinants were selected as difficult-to-treat pathogens. ESBLs and MBLs genes were characterized by PCR and sequencing. The activity of ATM in combination with seven different BLIs (clavulanate, sulbactam, tazobactam, vaborbactam, avibactam, relebactam, zidebactam) was assessed by microdilution assay and time–kill curve. ATM plus avibactam was the most effective combination, able to restore ATM susceptibility in four out of nine tested isolates, reaching in some cases a 128-fold reduction of the MIC of ATM. In addition, relebactam and zidebactam showed to be effective, but with lesser reduction of the MIC of ATM. E. meningoseptica and C. indologenes were not inhibited by any ATM–BLI combination. ATM–BLI combinations demonstrated to be promising against MBL and ESBL co-producers, hence providing multiple options for treatment of related infections. However, no effective combination was found for some non-fermentative bacilli, suggesting the presence of additional resistance mechanisms that complicate the choice of an active therapy.

scholarly journals Synergistic bactericide and antibiotic effects of dimeric, tetrameric, or palindromic peptides containing the RWQWR motif against Gram-positive and Gram-negative strains

RSC Advances ◽  
2019 ◽  
Vol 9 (13) ◽  
pp. 7239-7245 ◽  
Author(s):  
Yerly Vargas-Casanova ◽  
Andrea Verónica Rodríguez-Mayor ◽  
Karen Johanna Cardenas ◽  
Aura Lucía Leal-Castro ◽  
Liliana Constanza Muñoz-Molina ◽  
...  
Keyword(s):  
Gram Positive ◽  
Gram Negative ◽  
Kill Curve ◽  
Blue Line ◽  
Time Kill

Time-kill curve plot. Peptide LfcinB (20–25)4againstS. aureusATCC 25923. The peptide was tested at concentrations corresponding to MIC (blue line), 2 MIC (pink line) and 4 MIC (orange line) values.

In vitro synergy of ceftolozane/tazobactam in combination with fosfomycin or aztreonam against MDR Pseudomonas aeruginosa

2020 ◽  
Vol 75 (7) ◽  
pp. 1874-1878 ◽  
Author(s):  
Gabriel T Cuba ◽  
Gerlan Rocha-Santos ◽  
Rodrigo Cayô ◽  
Ana Paula Streling ◽  
Carolina S Nodari ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Resistance Mechanisms ◽  
Density Reduction ◽  
Carbapenem Resistant ◽  
Gradient Diffusion ◽  
Fold Reduction ◽  
The Face ◽  
Antimicrobial Synergy ◽  
Time Kill

Abstract Objectives Carbapenem-resistant Pseudomonas aeruginosa (CR-PSA) imposes great limitations on empirical therapeutic choices, which are further complicated by metallo-β-lactamase production. This study evaluated in vitro antimicrobial synergy of ceftolozane/tazobactam in combination with aztreonam and fosfomycin against MDR PSA. Methods MICs were determined by broth microdilution and gradient strips. The effect of ceftolozane/tazobactam+aztreonam and ceftolozane/tazobactam+fosfomycin combinations were tested against 27 MDR PSA isolates carrying blaSPM-1 (n = 13), blaIMP (n = 4), blaVIM (n = 3), blaGES-1 (n = 2) and blaCTX-M-like (n = 2), and 3 isolates with no acquired β-lactamase production detected by gradient diffusion strip crossing (GDSC). Six genetically unrelated SPM-1-producing isolates were also evaluated by time–kill analysis (TKA). Results All CR-PSA isolates harbouring blaSPM-1, blaGES-1 and blaIMP-1 were categorized as resistant to ceftolozane/tazobactam, meropenem and fosfomycin, with 70% being susceptible to aztreonam. Synergism for ceftolozane/tazobactam+fosfomycin and ceftolozane/tazobactam+aztreonam combinations was observed for 88.9% (24/27) and 18.5% (5/27) of the isolates by GDSC, respectively. A 3- to 9-fold reduction in ceftolozane/tazobactam MICs was observed, depending on the combination. Ceftolozane/tazobactam+fosfomycin was synergistic by TKA against one of six SPM-1-producing isolates, with additional non-synergistic bacterial density reduction for another isolate. Aztreonam peak concentrations alone demonstrated a ≥3 log10 cfu/mL reduction against all six isolates, but all strains were within the susceptible range for the drug. No antagonism was observed. Conclusions In the context of increasing CR-PSA and the genetic diversity of resistance mechanisms, new combinations and stewardship strategies may need to be explored in the face of increasingly difficult to treat pathogens.

scholarly journals In VitroAntibacterial and Antibiofilm Activities of Chlorogenic Acid against Clinical Isolates ofStenotrophomonas maltophiliaincluding the Trimethoprim/Sulfamethoxazole Resistant Strain

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Arunkumar Karunanidhi ◽  
Renjan Thomas ◽  
Alex van Belkum ◽  
Vasanthakumari Neela
Keyword(s):  
Chlorogenic Acid ◽  
Inhibition Zone ◽  
Clinical Isolates ◽  
Antibiofilm Activity ◽  
Log Reduction ◽  
Fold Reduction ◽  
Viable Bacteria ◽  
Study Support ◽  
Time Kill

Thein vitroantibacterial and antibiofilm activity of chlorogenic acid against clinical isolates ofStenotrophomonas maltophiliawas investigated through disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill and biofilm assays. A total of 9 clinicalS. maltophiliaisolates including one isolate resistant to trimethoprim/sulfamethoxazole (TMP/SMX) were tested. The inhibition zone sizes for the isolates ranged from 17 to 29 mm, while the MIC and MBC values ranged from 8 to 16 μg mL−1and 16 to 32 μg mL−1. Chlorogenic acid appeared to be strongly bactericidal at 4x MIC, with a 2-log reduction in viable bacteria at 10 h.In vitroantibiofilm testing showed a 4-fold reduction in biofilm viability at 4x MIC compared to 1x MIC values (0.085<0.397A 490 nm) of chlorogenic acid. The data from this study support the notion that the chlorogenic acid has promisingin vitroantibacterial and antibiofilm activities againstS. maltophilia.

scholarly journals Antimicrobial activity of copper surfaces against carbapenemase-producing contemporary Gram-negative clinical isolates

2012 ◽  
Vol 68 (4) ◽  
pp. 852-857 ◽  
Author(s):  
M. Souli ◽  
I. Galani ◽  
D. Plachouras ◽  
T. Panagea ◽  
A. Armaganidis ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Clinical Isolates ◽  
Gram Negative ◽  
Copper Surfaces

In Vitro Antimicrobial Activity of “Last-Resort” Antibiotics Against Unusual Nonfermenting Gram-Negative Bacilli Clinical Isolates

2012 ◽  
Vol 18 (4) ◽  
pp. 396-401 ◽  
Author(s):  
Herve Jacquier ◽  
Alban Le Monnier ◽  
Etienne Carbonnelle ◽  
Stephane Corvec ◽  
Marina Illiaquer ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Clinical Isolates ◽  
Gram Negative ◽  
In Vitro Antimicrobial Activity

scholarly journals In vitro antimicrobial activity of five essential oils on multi-drug resistant Gram-negative clinical isolates

2016 ◽  
Vol 5 (3) ◽  
pp. 212 ◽  
Author(s):  
Hercules Sakkas ◽  
Panagiota Gousia ◽  
Vangelis Economou ◽  
Vassilios Sakkas ◽  
Stefanos Petsios ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Essential Oils ◽  
Clinical Isolates ◽  
Drug Resistant ◽  
Gram Negative ◽  
In Vitro Antimicrobial Activity

scholarly journals Variability in carbapenemase activity of intrinsic OxaAb (OXA-51-like) beta-lactamase enzymes in Acinetobacter baumannii

2020 ◽  
Author(s):  
Yuiko Takebayashi ◽  
Jacqueline Findlay ◽  
Kate J. Heesom ◽  
Philip J. Warburton ◽  
Matthew B. Avison ◽  
...  
Keyword(s):  
Molecular Evolution ◽  
Efflux Pump ◽  
Carbapenem Resistance ◽  
Resistance Mechanisms ◽  
Clinical Isolates ◽  
Beta Lactamase ◽  
Resistance Factors ◽  
Evolution Analysis ◽  
Ms Analysis ◽  
Additional Resistance

ABSTRACTObjectivesThis study aimed to measure the variability in carbapenem susceptibility conferred by different OxaAb variants, characterise the molecular evolution of oxaAb and elucidate the contribution of OxaAb and other possible carbapenem resistance factors in the clinical isolates using WGS and LC-MS/MS.MethodsDisc susceptibility and MIC broth microdilution tests were performed on ten clinical A. baumannii isolates and interpreted according to CLSI guidelines. Imipenem and meropenem MICs were evaluated for all oxaAb variants cloned into susceptible A. baumannii CIP70.10 and increased adeABC efflux pump gene expression BM4547 backgrounds, with and without their natural promoters. Molecular evolution analysis of the oxaAb variants was performed using FastTree and SplitsTree4. Resistance determinants were studied in the clinical isolates using WGS and LC-MS/MS analysis.ResultsOxaAb(82), OxaAb(83), OxaAb(107), and OxaAb(110) carrying I129L and L167V substitutions increased carbapenem MICs when transferred into susceptible A. baumannii backgrounds without an upstream IS element. Carbapenem resistance was conferred with the addition of their natural upstream ISAba1 promoter. LC-MS/MS analysis on the original clinical isolates showed no differences in expression levels of proteins commonly associated with carbapenem resistance.ConclusionsISAba1-driven overexpression of OxaAb variants with substitutions I129L and L167V confers carbapenem resistance with no need for additional resistance mechanisms.

scholarly journals Antimicrobial Effect of Bacteriocin produced Pediococcus pentosaceus on some clinical isolates

2017 ◽  
Vol 27 (5) ◽  
pp. 26 ◽  
Author(s):  
Nehad A. Taher
Keyword(s):  
Antimicrobial Activity ◽  
Protein Concentration ◽  
Antimicrobial Effect ◽  
Clinical Isolates ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Pediococcus Pentosaceus ◽  
Gram Positive Bacteria ◽  
Agar Plug ◽  
Made In

About 10 isolates of Pediococcus sp were isolated from different cheese made in Iraq, These isolates were identified morphologically and biochemically and Api20 kit, thus there was only 6 isolate were identified as Pediococcus pentosaceus (60%).In this study, we investigate, the effect of crude Bacteriocin from Pediococcus pentosaceus on 30 clinical isolates (5 E.coli, 5 Klepsiella pneumoniae, 5 Staphylococcus aureus, 5 Pseudomonas aeroginosa, 5 Bacillus subtilis, 5 Candida albicans). The protein concentration of this Bacteriocin was measured 67mg\ml by Bradford method and used as (1:2) by vol during the measuring the antimicrobial activity against the above clinical isolates by two methods wells and  agar plug assay. The results showed that  the inhibitory activity of this Bacteriocin was higher by wells method than agar pluq assay against Gram–positive bacteria or Gram-negative bacteria and yeast under this study.

scholarly journals Pathogenicity Genomic Island-Associated CrpP-Like Fluoroquinolone-Modifying Enzymes among Pseudomonas aeruginosa Clinical Isolates in Europe

2020 ◽  
Vol 64 (7) ◽  
Author(s):  
José Manuel Ortiz de la Rosa ◽  
Patrice Nordmann ◽  
Laurent Poirel
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Genomic Island ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Genomic Islands ◽  
Clinical Isolates ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type ◽  
Genes Encoding

ABSTRACT Many transferable quinolone resistance mechanisms have been identified in Gram-negative bacteria. The plasmid-encoded 65-amino-acid-long ciprofloxacin-modifying enzyme CrpP was recently identified in Pseudomonas aeruginosa isolates. We analyzed a collection of 100 clonally unrelated and multidrug-resistant P. aeruginosa clinical isolates, among which 46 were positive for crpP-like genes, encoding five CrpP variants conferring variable levels of reduced susceptibility to fluoroquinolones. These crpP-like genes were chromosomally located as part of pathogenicity genomic islands.

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