In vitro inferiority of ceftazidime compared with other beta-lactams for viridans group Streptococcus bacteremia in pediatric oncology patients: implications for antibiotic choices.

Viridans group Streptococcus (VGS) is a leading cause of bacteremia in pediatric oncology patients, primarily in children with acute myeloid leukemia or after hematopoietic stem cell transplantation. We retrospectively identified all positive blood cultures in oncology patients at the British Columbia Children's Hospital for a period of 54 months. VGS was the second most commonly isolated pathogen, present in 19% of all the positive blood cultures. Susceptibility analysis of 46 VGS isolates from that period was performed using the Etest method for penicillin, cefotaxime, ceftazidime, and piperacillin/tazobactam. The geometric mean minimal inhibitory concentration for ceftazidime was found to be 9 to 12-fold higher than for any other beta-lactam antibiotic. Penicillin resistance was of 13% with an additional 20% of samples with intermediate susceptibility. The study underscores the prevalence of VGS bacteremia in pediatric patients, especially with acute myeloid leukemia or postallogeneic hematopoietic stem cell transplantation, and the in vitro inferiority of ceftazidime compared with other beta-lactams in that context. We conclude that monotherapy with ceftazidime, or its use along with an aminoglycoside, is not an optimal therapy in pediatric oncology patients with febrile neutropenia.

Bloodstream infections in pediatric ECLS: usefulness of daily blood culture monitoring and predictive value of biological markers. The British Columbia experience.

INTRODUCTION: The incidence of bloodstream infection (BSI) in extracorporeal life support (ECLS) is reported between 0.9 and 19.5%. In January 2006, the Extracorporeal Life Support Organization (ELSO) reported an overall incidence of 8.78% distributed as follows: respiratory: 6.5% (neonatal), 20.8% (pediatric); cardiac: 8.2% (neonatal) and 12.6% (pediatric). METHOD: At BC Children's Hospital (BCCH) daily surveillance blood cultures (BC) are performed and antibiotic prophylaxis is not routinely recommended. Positive BC (BC+) were reviewed, including resistance profiles, collection time of BC+, time to positivity and mortality. White blood cell count, absolute neutrophile count, immature/total ratio, platelet count, fibrinogen and lactate were analyzed 48, 24 and 0 h prior to BSI. A univariate linear regression analysis was performed. RESULTS: From 1999 to 2005, 89 patients underwent ECLS. After exclusion, 84 patients were reviewed. The attack rate was 22.6% (19 BSI) and 13.1% after exclusion of coagulase-negative staphylococci (n = 8). BSI patients were significantly longer on ECLS (157 h) compared to the no-BSI group (127 h, 95% CI: 106-148). Six BSI patients died on ECLS (35%; 4 congenital diaphragmatic hernias, 1 hypoplastic left heart syndrome and 1 after a tetralogy repair). BCCH survival on ECLS was 71 and 58% at discharge, which is comparable to previous reports. No patient died primarily because of BSI. No BSI predictor was identified, although lactate may show a decreasing trend before BSI (P = 0.102). CONCLUSION: Compared with ELSO, the studied BSI incidence was higher with a comparable mortality. We speculate that our BSI rate is explained by underreporting of "contaminants" in the literature, the use of broad-spectrum antibiotic prophylaxis and a higher yield with daily monitoring BC. We support daily surveillance blood cultures as an alternative to antibiotic prophylaxis in the management of patients on ECLS.

Is the healthy middle ear a normally sterile site?

OBJECTIVE: To systematically evaluate the presumption that the healthy middle ear becomes colonized with organisms via the patent eustachian tube using modern microbiologic techniques. STUDY DESIGN: Sterile saline washings were obtained from the middle ear of patients in a prospective fashion. SETTING: Tertiary/quaternary referral centers. PATIENTS: Pediatric and adult patients undergoing cochlear implantation surgery. INTERVENTION(S): Standard bacterial and viral cultures, and nucleic acid amplification techniques. MAIN OUTCOME MEASURE(S): Identification of organisms. RESULTS: Specimens were obtained from 13 children and 9 adults. No organisms were identified in any of the specimens, either through standard culture or PCR testing. CONCLUSION: The presumption that the healthy middle ear is colonized by bacteria from the nasopharynx is unsubstantiated.

Our patients do not need endocarditis prophylaxis for genitourinary tract procedures: insights from the 2007 American Heart Association guidelines.

The 2007 American Heart Association guidelines for the prevention of infective endocarditis have dramatically reduced both the types of eligible procedures and the types of eligible cardiac lesions that require prophylaxis. Antibiotic prophylaxis to prevent infective endocarditis is not indicated for any patient undergoing obstetric and/or gynaecological procedures, not even for patients with underlying cardiac lesions with the highest risk of developing complications from endocarditis. This sharp departure from previously published guidelines relies on the recognition that endocarditis is more likely to develop from "randomly occurring" bacteremia (e.g., from brushing teeth) than from invasive procedures and that antibiotic prophylaxis has not been proven to be effective. A short discussion on enterococcal infections associated to obstetric and gynaecological procedures and therapeutic implications is presented.