Rhonda Ferrett

Washington University in St. Louis, San Luis, Missouri, United States

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Publications (3)6.9 Total impact

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    ABSTRACT: To determine the source of an outbreak of Salmonella javiana infection. Case-control study. A total of 101 culture-confirmed cases and 540 epidemiologically linked cases were detected between May 26, 2003, and June 16, 2003, in hospital employees, patients, and visitors. Asymptomatic employees who had eaten in the hospital cafeteria between May 30 and June 4, 2003, and had had no gastroenteritis symptoms after May 1, 2003, were chosen as control subjects. A 235-bed academic tertiary care children's hospital. Isolates from 100 of 101 culture-confirmed cases had identical pulsed-field gel electrophoresis patterns. A foodhandler with symptoms of gastroenteritis was the presumed index subject. In multivariate analysis, case subjects were more likely than control subjects to have consumed items from the salad bar (adjusted odds ratio [aOR], 5.3; 95% confidence interval [CI], 2.3-12.1) and to have eaten in the cafeteria on May 28 (aOR, 9.4; 95% CI, 1.8-49.5), May 30 (aOR, 3.6; 95% CI, 1.0-12.7), and/or June 3 (aOR, 4.0; 95% CI, 1.4-11.3). Foodhandlers who worked while they had symptoms of gastroenteritis likely contributed to the propagation of the outbreak. This large outbreak was rapidly controlled through the use of an incident command center.
    Infection Control and Hospital Epidemiology 07/2006; 27(6):586-92. DOI:10.1086/506483 · 4.18 Impact Factor
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    ABSTRACT: In evaluations of sensitive rapid tests for group A streptococci such as the optical immunoassay (OIA), some samples are positive by the antigen test but negative by culture. A method is needed for resolving these discrepant results. To develop a PCR-based assay to detect group A streptococci and to use it to establish a reference standard for evaluating an OIA for group A streptococcal antigen. A PCR assay that detects a segment of the MF gene of Streptococcus pyogenes was developed for the detection of group A streptococci in throat swabs. Paired swabs were obtained from 200 children with symptomatic pharyngitis and used to perform OIA, agar culture, broth-enhanced culture and PCR. As a reference standard any patient with group A streptococci detected by either culture or PCR was considered to be truly positive. In comparison to agar and broth-enhanced culture procedures, OIA had sensitivities of 82 and 80% and specificities of 87 and 89%, respectively. Eight (44%) of 18 samples that were positive by OIA but negative by culture were positive for group A streptococci by PCR. Compared with the reference standard, sensitivities were OIA 76%, agar culture 79%, broth-enhanced culture 86% and PCR 96%. The specificity of OIA was 92%. PCR can be used to establish a reference standard for evaluating rapid tests for group A streptococci. With this reference standard OIA was nearly as sensitive as but less specific than agar culture for detection of group A streptococci. Maximum detection requires use of both tests.
    The Pediatric Infectious Disease Journal 09/1997; 16(8):748-53. DOI:10.1097/00006454-199708000-00004 · 2.72 Impact Factor
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    ABSTRACT: We compared three automated microbiology systems: MicroScan Walk-Away ® (DADE BEHRING INC., West Sacramento, CA), Phoenix ™ [P] (Becton Dickinson Diagnostic Systems, Sparks, MD) and VITEK·TWO ® [V] (bioMérieux, Durham, NC). Two different panels were used with the MicroScan system: Rapid [MR] and conventional [MC]. Organisms tested included clinical isolates from cultures obtained from a variety of body sites from patients at SLCH and a subset of challenge organisms.