The activity of cefditoren and six other cephalosporins was tested against 250 pneumococci, including strains resistant to macrolides and quinolones. Cefditoren gave the lowest MICs, with MIC(50) and MIC(90) values of < or =0.016/0.03, 0.125/0.5 and 0.5/2.0 mg/L for penicillin-susceptible, -intermediate and -resistant pneumococci, respectively. A time-kill study of 12 pneumococcal strains with varying drug susceptibilities showed that cefditoren, at 2 x MIC, gave 99% killing of all strains after 12 h, with 99.9% killing after 24 h. Other cephalosporins gave similar kill kinetics but at higher concentrations. Against 160 Haemophilus influenzae, cefditoren had the lowest MICs (MIC(50) and MIC(90) both < or =0.016 mg/L), irrespective of beta-lactamase production. Time-kill studies of cefditoren compared with five other oral cephalosporins showed that cefditoren, at 8 x MIC, was bactericidal against 8/9 strains and gave 90% killing of all strains at the MIC after 12 h. Activity was bactericidal (99.9% killing) after 24 h with all drugs tested. Multistep studies of four penicillin-susceptible, four penicillin-intermediate and four penicillin-resistant strains showed that cefditoren, co-amoxiclav and cefprozil did not select for resistant mutants after 50 subcultures, compared with cefuroxime and azithromycin, where resistant mutants were selected in two and nine strains, respectively. Single-step mutation studies showed that cefditoren, at the MIC, had the lowest frequency of spontaneous mutants compared with other drugs.
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http://dx.doi.org/10.1093/jac/dkf076 | DOI Listing |
Arch Microbiol
November 2024
School of Life Science and Technology, China Pharmaceutical University, 639 Longmian Road, Nanjing, 211198, Jiangsu, China.
Penicillin-binding proteins (PBPs) are the targets of β-lactam antibiotics; however, changes in the affinity of PBPs for beta-lactam antibiotics often affect the susceptibility of bacteria to antibiotics. The purpose of this study was to elucidate the mechanism by which cefditoren, an oral third-generation cephalosporin, binds PBPs. The minimal inhibitory concentration (MIC), bactericidal curves, and inhibition zone comparisons were assessed to evaluate the antibacterial activity of cefditoren.
View Article and Find Full Text PDFPharm Res
July 2023
Division of Pharmacodynamics, Keio University Faculty of Pharmacy, 1-5-30 Shibakoen, Minato-Ku, Tokyo, 105-8512, Japan.
New Microbiol
February 2023
Infectious Diseases Clinic, Azienda Sanitaria Universitaria del Friuli Centrale (ASUFC), Udine, Italy.
Cefditoren is an oral third-generation cephalosporin with a large spectrum activity against Gram-negative and Gram-positive bacteria which are reported to be responsible for respiratory tract and skin and skin structure infections. In this work we reviewed the pharmacodynamics, pharmacokinetics, and the main clinical indications of cefditoren. Similarly to other beta-lactams, cefditoren is a time-dependent antibiotic, and its "best" PK/PD target is probably 40% dosing interval time > 4- 5-fold MIC and 40-70% dosing interval time > 4- 5-fold MIC for bacteriostatic and bactericidal effect, respectively.
View Article and Find Full Text PDFLancet Microbe
October 2022
Spanish Pneumococcal Reference Laboratory, National Center for Microbiology, Instituto de Salud Carlos III, Madrid, Spain; CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain. Electronic address:
Background: Epidemiological studies are necessary to explore the effect of current pneumococcal conjugate vaccines (PCVs) against antibiotic resistance, including the rise of non-vaccine serotypes that are resistant to antibiotics. Hence, epidemiological changes in the antimicrobial pattern of Streptococcus pneumoniae before and during the first year of the COVID-19 pandemic were studied.
Methods: In this national surveillance study, we characterised the antimicrobial susceptibility to a panel of antibiotics in 3017 pneumococcal clinical isolates with reduced susceptibility to penicillin during 2004-20 in Spain.
Antimicrob Agents Chemother
June 2022
Division of Infectious Diseases, grid.471401.7grid.21107.35grid.471401.7grid.21107.35Johns Hopkins University School of Medicinegrid.471401.7, Baltimore, Maryland, USA.
Mycobacteroides abscessus () is an emerging environmental microbe that causes chronic lung disease in patients with compromised lung function such as cystic fibrosis and bronchiectasis. It is intrinsically resistant to most antibiotics, therefore there are only few antibiotics that can be repurposed to treat disease. Although current recommendations require daily intake of multiple antibiotics for more than a year, cure rate is low and often associated with significant adverse events.
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