title: In Vitro Efficacy of Six Alternative Antibiotics against Multidrug Resistant Escherichia Coli and Klebsiella Pneumoniae from Urinary Tract Infections.
abstract: BACKGROUND
  Increasing resistance in Escherichia coli and Klebsiella pneumoniae to firstline antibiotics makes therapeutic options for urinary tract infections (UTIs) challenging. This study investigated the in vitro efficacies of 6 antibiotics against multidrug resistant (MDR) uropathogens.
  
  
  METHODS
  Minimum inhibitory concentrations to ceftibuten, cefpodoxime, fosfomycin, mecillinam, temocillin, and trimethoprim were determined against 155 MDR-isolates of E. coli and K. pneumoniae. The presence of extended-spectrum beta-lactamases (ESBL) and plasmid-borne AmpC enzymes was determined by phenotypic testing with genotyping performed by multiplex polymerase chain reaction.
  
  
  RESULTS
  Temocillin demonstrated highest susceptibility rates for both E. coli (95%) and K. pneumoniae (95%) when breakpoints for uncomplicated UTIs were applied; however, temocillin susceptibility was substantially lower when "systemic infection" breakpoints were used. Fosfomycin demonstrated the best in vitro efficacy of the orally available agents, with 78% and 69% of E. coli and K. pneumoniae isolates susceptible, respectively. The next most effective antibiotics were ceftibuten (45%) and mecillinam (32%). ESBL and ampC genes were present in 47 (30%) and 59 (38%) isolates.
  
  
  CONCLUSIONS
  This study demonstrated few oral therapeutic options for MDR-uropathogens, with fosfomycin demonstrating the best in vitro activity.
authors.affiliation: Department of Laboratory Medicine, Changi General Hospital, Singapore.
authors.forename: Yu Ting
authors.initials: YT
authors.lastname: Chen
authors.forename: Katzrin
authors.initials: K
authors.lastname: Ahmad Murad
authors.forename: Lily Sy
authors.initials: LS
authors.lastname: Ng
authors.forename: Jonathan Th
authors.initials: JT
authors.lastname: Seah
authors.forename: Joon Jae
authors.initials: JJ
authors.lastname: Park
authors.forename: Thean Yen
authors.initials: TY
authors.lastname: Tan
mesh_terms: D000560:Amdinocillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D000077722:Ceftibuten; D015296:Ceftizoxime / Q000031:analogs & derivatives / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D004927:Escherichia coli Infections / Q000382:microbiology; D005578:Fosfomycin / Q000494:pharmacology; D005838:Genotype; D006801:Humans; D066298:In Vitro Techniques; D007710:Klebsiella Infections / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000235:genetics; D008826:Microbial Sensitivity Tests; D060885:Multiplex Polymerase Chain Reaction; D010406:Penicillins / Q000494:pharmacology; D012846:Singapore; D014295:Trimethoprim / Q000494:pharmacology; D014552:Urinary Tract Infections / Q000382:microbiology*; D001618:beta-Lactamases / Q000235:genetics; D000097623:Cefpodoxime
chemical_list: D000560:Amdinocillin; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D000077722:Ceftibuten; D015296:Ceftizoxime; D002511:Cephalosporins; D005578:Fosfomycin; D010406:Penicillins; D014295:Trimethoprim; D001618:beta-Lactamases; D000097623:Cefpodoxime; C031367:temocillin; C048795:AmpC beta-lactamases