Meropenem, a new parenteral carbapenem, was tested in vitro by an agar-dilution method against 373 standard strains (aerobes and anaerobes) and against nine expanded-spectrum beta-lactamase-producing strains and their transconjugants (5 CTX-1, 2 CAZ-1, 2 CAZ-2). Meropenem was compared with methicillin, imipenem, piperacillin, cefoxitin, cefotaxime, ceftazidime, gentamicin, chloramphenicol, clindamycin, ciprofloxacin, vancomycin and metronidazole. Meropenem and imipenem exhibited an extended spectrum of activity, with low MICs. Only methicillin-resistant staphylococci, and Pseudomonas (Xanthomonas) maltophilia were resistant. Of the carbapenems, imipenem was more active against methicillin-susceptible staphylococci, streptococci and Enterococcus faecalis, but meropenem was markedly more active against all the Enterobacteriaceae and some pseudomonads. Both had similar activity against Ps. aeruginosa, Acinetobacter spp. and anaerobes. The carbapenem MICs were very low for Enterol acteriaceae producing the expanded-spectrum beta-lactamases. Against CTX-1-producing strains resistant to cefotaxime and ceftazidime and against CAZ-1 or CAZ-2-producers highly resistant to ceftazidime meropenem was the most active, with MICs lower (0.03-0.12 mg/l) than those of imipenem (0.06-0.5 mg/l), for wild type producers and their transconjugants.
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http://dx.doi.org/10.1093/jac/24.suppl_a.133 | DOI Listing |
Antimicrob Agents Chemother
May 2024
Team ReSIST, INSERM U1184, School of Medicine Université Paris-Saclay, LabEx LERMIT, Le Kremlin-Bicêtre, France.
OXA-48 has rapidly disseminated worldwide and become one of the most common carbapenemases in many countries with more than 45 variants reported with, in some cases, significant differences in their hydrolysis profiles. The R214 residue, located in the ß5-ß6 loop, is crucial for the carbapenemase activity, as it stabilizes carbapenems in the active site and maintains the shape of the active site through interactions with D159. In this study, we have characterized a novel variant of OXA-48, OXA-933 with a single D159N change.
View Article and Find Full Text PDFInt J Antimicrob Agents
January 2024
Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; Clinical Microbiology and Virology Unit, Florence Careggi University Hospital, Florence, Italy.
Objectives: To investigate a ceftazidime/avibactam (CZA)-resistant Klebsiella pneumoniae (NE368), isolated from a patient exposed to CZA, expressing a novel K. pneumoniae carbapenemase (KPC)-3 variant (KPC-109).
Methods: Antimicrobial susceptibility testing was performed by reference broth microdilution.
J Glob Antimicrob Resist
December 2023
Division of Zoonosis Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan; Graduate School of Veterinary Science, Osaka Metropolitan University, Izumisano, Osaka, Japan. Electronic address:
Objectives: The production of expanded-spectrum beta-lactamases (ESBLs) and fluoroquinolone resistance in Enterobacteriaceae has become a global concern. The aim of this study was to investigate the spread of ESBL-producing and fluoroquinolone-resistant avian pathogenic Escherichia coli (APEC) in Kagoshima, a prefecture with the largest amount of poultry in Japan.
Methods: The antimicrobial susceptibility and genetic characteristics of 228 APEC strains isolated from 57 farms in Kagoshima Prefecture, Japan, between 2005 and 2017 were analysed.
Antibiotics (Basel)
July 2023
Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, 25123 Brescia, Italy.
Introduction: Not enough data exist to inform the optimal duration and type of antimicrobial therapy against GN infections in critically ill patients.
Methods: Narrative review based on a literature search through PubMed and Cochrane using the following keywords: "multi-drug resistant (MDR)", "extensively drug resistant (XDR)", "pan-drug-resistant (PDR)", "difficult-to-treat (DTR) Gram-negative infection," "antibiotic duration therapy", "antibiotic combination therapy" "antibiotic monotherapy" "Gram-negative bacteremia", "Gram-negative pneumonia", and "Gram-negative intra-abdominal infection".
Results: Current literature data suggest adopting longer (≥10-14 days) courses of synergistic combination therapy due to the high global prevalence of ESBL-producing (45-50%), MDR (35%), XDR (15-20%), PDR (5.
Front Microbiol
May 2023
Key Laboratory of Animal Disease and Human Health of Sichuan, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.
Introduction: is a multi-host pathogen that causes diseases of varying severity in a wide range of mammals, including humans. is resistant to multiple antibiotics and has acquired the ability to produce expanded spectrum of β-lactamases, leading to serious public health problems. However, the available information on isolated from feces of dogs, is still poorly understood, as is the correlation between its virulence-associated genes (VAGs) and antibiotic resistance genes (ARGs).
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