BACKGROUND: In a 2006 WHO report, diarrheal diseases ranked second among conditions afflicting children. Pediatric acute diarrhea, although most often the result of a gastrointestinal infection, can also occur as a result of antibiotic exposure. This is often referred to as antibiotic-associated diarrhea (AAD). Previous research suggests that probiotics may be effective in the treatment or prevention of various types of PAD. METHODS: The first study involved a systematic review and meta-analysis of RCTs involving probiotics as an adjunct to antibiotics for preventing AAD in children. The second study was a systematic review of definitions and primary outcome measures employed in RCTs of PAD. The third study used a modified Delphi consensus procedure to develop a new instrument for evaluating the severity of PAD. The study involved steering committee discussions (phase 1) and two electronic surveys (phase 2 and 3) of leading experts in measurement and clinical gastroenterology. RESULTS: The per protocol meta-analysis of ten RCTs significantly favored probiotics to prevent the incidence of diarrhea (NNT = 10). However, this effect did not withstand ITT analysis and among included trials there was considerable inconsistency regarding definitions for the reviews primary outcome measure, the incidence of diarrhea. Study two identified 121 RCTs that reported 62 unique definitions of diarrhea, 64 unique definitions of diarrhea resolution and 62 unique primary outcome measures. Thirty-one trials used grading systems to support outcome evaluation. However, none of the trials (or their citations) reported evidence of their validation. In study three experts agreed on the inclusion of five attributes containing 13 items. Attributes proposed for the IPADDS include: Diarrhea Frequency and Duration, Vomiting Frequency and Duration, Fever, Restrictions in Normal Daily Activities and Dehydration. CONCLUSION: It is premature to draw a valid conclusion about the efficacy of probiotics for pediatric AAD. Definitions of diarrhea and primary outcome measures in RCTs of PAD are heterogeneous and lack evidence of validity. The third study represents content validity evidence for IPADDS. A numerical scoring system needs to be added and further empirical evidence of reliability and validity are required. / Experimental Medicine

Clostridium difficile is the most common infectious cause of nosocomial diarrhea, affecting thousands of patients annually and exacting enormous costs on the U.S. health care system. Early diagnosis is critical to prevent transmission and reduce morbidity and mortality, yet sensitive and specific diagnostic tests with a quick turnaround time are lacking. The objective of this study was to determine if a new commercially available real time polymerase chain reaction (PCR) test would prove more rapid, sensitive and specific than standard methods for the diagnosis of C. difficile infection (CDI). BD GeneOhm Cdiff assay, a real-time PCR assay for detection of C. difficile toxin B (tcdB) gene, was compared with Tox A/B II ELISA and a two-step algorithm which includes C. Diff Chek-60 Glutamate Dehydrogenase (GDH)-antigen assay followed by cytotoxin neutralization. Four-hundred liquid or semisolid stools submitted for diagnostic C. difficile testing were selected: 200 GDH antigen-positive and 200 GDH antigen-negative. All samples were tested by the C. Diff Chek-60 GDH antigen, cytotoxin neutralization, Toxin A/B II ELISA, and BD GeneOhm Cdiff assay. Discrepant specimens were tested by toxigenic culture as an independent gold standard. Chart review was performed on patients with discrepant specimens. As BD GeneOhm Cdiff assay was not FDA-cleared at the time of study, PCR results were not clinically reported. Of 200 GDH-positive samples, 71 were positive by Tox A/B II, 88 were positive by the two-step method, 93 were positive by PCR, and 96 were positive by GDH-antigen only. Of 200 GDH-negative samples, 3 were positive by PCR only. Toxigenic culture was performed on 41 samples with discrepant results and 39 were culture-positive. After culture resolution of discrepants, Tox A/B II detected 70 (66.7%), the two-step method detected 87 (82.9%), and PCR detected 96 (91.4%) of 105 true positives. The BD Gene-Ohm Cdiff assay was more sensitive in detecting toxigenic C. difficile than Tox A/B II (p <0.0001); however, the difference between PCR and the two-step method was not significant (p=0.1237). The BD GeneOhm Cdiff assay took a similar amount of time to perform as the Tox A/B II and was more rapid than the two-step method. Chart review revealed that 18 patients with cytotoxin-negative, PCR-positive discrepant samples were given 1-2 days of therapy (n=8), or no treatment at all (n=10). Yet symptoms resolved and no further C. difficile testing was requested for 13 of 18 patients for 6-8 months after hospital discharge. Only one patient had a subsequent cytotoxin positive stool submitted 22 days after the study sample was tested. Enhanced sensitivity and rapid turnaround time make the BD GeneOhm Cdiff assay an important advance in the diagnosis of toxigenic C. difficile infection. The BD GeneOhm Cdiff assay is significantly more sensitive than a commonly-used ELISA toxin assay and has a sensitivity and specificity comparable to the two-step method. Its turnaround time is similar to ELISA toxin assays and more rapid than the two-step method. Disadvantages to implementation of BD GeneOhm Cdiff assay include increased cost and potential treatment of asymptomatic carriers and mild, self-resolving disease.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 33-40).

No description available.

Thesis (D.P.H.)--University of Hawaii at Manoa, 1994. / Includes bibliographical references (leaves 161-170). / Microfiche. / xiv, 170 leaves, bound ill., col. map 29 cm

Thesis (M.CM)--Hong Kong Baptist University, 2006. / Dissertation submitted to the School of Chinese Medicine. Includes bibliographical references (leave 24).

Thesis (Ph.D.)--Murdoch University, 2004. / Thesis submitted to the Division of Health Sciences. Includes bibliographical references (leaves 145-167).

Dissertation (Ph.D.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references (p.281-340).

Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.

Thesis (M.Sc. (Pharmacology))--Mahidol University, 1984.