title: Antimicrobial susceptibility of blood culture isolates of viridans streptococci: relationship to a change in empirical antibiotic therapy in febrile neutropenia.
abstract: This study investigated the antibiotic susceptibilities of 67 isolates of viridans streptococci from 61 cases of bacteraemia in immunocompromised paediatric patients with malignancy. The majority of patients (87%) had received prior courses of empirical antibiotic therapy, which consisted of ceftazidime plus amikacin during period 1 and piperacillin/tazobactam plus amikacin during period 2. Susceptibility to vancomycin and quinupristin/dalfopristin was 100%. Susceptibility to beta-lactam antibiotics varied. For period 1, the geometric mean MICs of all beta-lactams tested against blood culture isolates (n = 31) exceeded those against isolates (n = 36) collected from blood after the change in empirical therapy (by 3.3-fold for ceftazidime, 2.8-fold for piperacillin/tazobactam and 1.6-fold for penicillin). The selection of a beta-lactam antibiotic for empirical therapy must be made with care, as repeated courses of certain agents may be more likely to select for viridans streptococci with diminished susceptibility.
authors.affiliation: Department of Microbiology, Royal Hospital for Sick Children, Yorkhill NHS Trust, Glasgow G3 8SJ, UK. helenkennedy@tinyworld.co.uk
authors.forename: H F
authors.initials: HF
authors.lastname: Kennedy
authors.forename: C G
authors.initials: CG
authors.lastname: Gemmell
authors.forename: J
authors.initials: J
authors.lastname: Bagg
authors.forename: B E
authors.initials: BE
authors.lastname: Gibson
authors.forename: J R
authors.initials: JR
authors.lastname: Michie
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D016470:Bacteremia / Q000188:drug therapy / Q000382:microbiology; D001769:Blood / Q000382:microbiology; D005334:Fever / Q000209:etiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D009503:Neutropenia / Q000097:blood / Q000150:complications / Q000188:drug therapy* / Q000382:microbiology; D010403:Penicillin Resistance; D013291:Streptococcus / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents