title: [Comparative urinary bactericidal activity of oral antibiotics against gram-positive pathogens].
abstract: In routine bacteriological laboratories the antibacterial activity of antibiotics is determined by in vitro testing, usually by disk-diffusion test. However, in vitro testing does not always reflect antibacterial efficiency of antibiotics in vivo. In this investigation, the urine samples obtained in a single oral dose pharmacokinetic study were examined for their bactericidal activity against a range of relevant Gram-positive urinary tract pathogens. Urinary bactericidal activity of linezolid had been previously compared with ciprofloxacin but not with other oral antibiotics such as beta-lactams. Linezolid showed satisfactory urinary bactericidal titres throughout the whole testing period against all Gram-positive cocci. Fluoroquinolones displayed high and persisting levels of urinary bactericidal activity against staphylococci, but their activity against enterococci was weaker. According to the results of ex-vivo testing amoxycillin could be recommended only for infections caused by E. faecalis. Amoxycillin combined with clavulanic acid can be considered as a therapeutic option for infections caused by S. saprophyticus and E. faecalis. Older cephalosporins had high titres only against S. saprophyticus. Their drawback is a short elimination half-time in urine resulting in rapid decrease of urinary bactericidal titers during dosing interval. Furthermore, they do not show activity against enterococci due to their intrinsic resistance to cephalosporins.
authors.affiliation: Zavod za mikrobiologiju, Medicinski fakultet Sveucilista u Zagrebu. branka.bedenic@zg.t-com.hr
authors.forename: Branka
authors.initials: B
authors.lastname: Bedenić
authors.forename: Ana
authors.initials: A
authors.lastname: Budimir
authors.forename: Ana
authors.initials: A
authors.lastname: Gverić
authors.forename: Vanda
authors.initials: V
authors.lastname: Plecko
authors.forename: Jasmina
authors.initials: J
authors.lastname: Vranes
authors.forename: Marina
authors.initials: M
authors.lastname: Bubonja-Sonje
authors.forename: Smilja
authors.initials: S
authors.lastname: Kalenić
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000494:pharmacology; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy* / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D014552:Urinary Tract Infections / Q000188:drug therapy* / Q000382:microbiology; D014556:Urine / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents