Biomedical subjects
Publications and source records attributed to Susan E Richardson.
Blastomycosis is an uncommon life-threatening disease caused by the dimorphic fungus Blastomyces dermatitidis. Estimates of the percentage of cases occurring in children range from 2% to 11%, and it is exceedingly rare in individuals less than 1 year of age. We present the case of an otherwise healthy infant with disseminated blastomycosis acquired in Northern Ontario and a brief review of the pediatric literature.
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We describe a 24-h protocol for the identification of patients who are positive for vancomycin-resistant Enterococcus faecium (VRE), using stool and rectal swab samples and VRE screening broth, automated DNA extraction, and real-time PCR for vanA and vanB genes. Compared to conventional screening methods, this protocol had a high sensitivity and specificity and a negative predictive value.
We describe a case of blastomycosis in an 8-year-old boy with Blastomyces-associated osteomyelitis and possible pulmonary involvement. We also identify 309 cases of blastomycosis in Ontario that were seen during a 10-year period, 57% of which occurred from 2001 to 2003. The overall incidence during the study period was 0.30 cases per 100,000 population. Most patients were from north Ontario (n = 188), where the incidence was 2.44 cases per 100,000. The incidence in the Toronto region was 0.29 per 100,000. Thirteen percent of cases occurred in children <19 years of age. These findings substantially increase the number of known cases in Ontario and Canada. Clinicians may encounter persons infected with Blastomyces dermatitidis and must be familiar with its signs and symptoms and be aware of locations, such as northwestern Ontario, where disease is endemic or hyperendemic. We advocate resuming blastomycosis as a reportable disease in Ontario to facilitate tracking cases.
Previous studies have shown high rates of asymptomatic carriage of toxin-producing Clostridium difficile in infants. We performed a retrospective case control study comparing infants younger than 1 year old with diarrhea and C. difficile toxin (CDT) in the stool, to age-matched controls with diarrhea lacking CDT in the stool. We found no difference in clinical characteristics including fever, vomiting, or hematochezia. Treatment with metronidazole had no significant effect on the clinical outcome. Alternative etiologies for diarrhea (most commonly viral) were found in more than 50% of patients in both groups. We recommend that other causes of diarrhea be considered before C. difficile colitis in this age group.
BACKGROUND: An outbreak of severe acute respiratory syndrome (SARS) began in Canada in February 2003. The initial diagnosis of SARS was based on clinical and epidemiological criteria. During the outbreak, molecular and serologic tests for the SARS-associated coronavirus (SARS-CoV) became available. However, without a "gold standard," it was impossible to determine the usefulness of these tests. We describe how these tests were used during the first phase of the SARS outbreak in Toronto and offer some recommendations that may be useful if SARS returns. METHODS: We examined the results of all diagnostic laboratory tests used in 117 patients admitted to hospitals in Toronto who met the Health Canada criteria for suspect or probable SARS. Focusing on tests for SARS-CoV, we attempted to determine the optimal specimen types and timing of specimen collection. RESULTS: Diagnostic test results for SARS-CoV were available for 110 of the 117 patients. SARS-CoV was detected by means of reverse-transcriptase polymerase chain reaction (RT-PCR) in at least one specimen in 59 (54.1%) of 109 patients. Serologic test results of convalescent samples were positive in 50 (96.2%) of 52 patients for whom paired serum samples were collected during the acute and convalescent phases of the illness. Of the 110 patients, 78 (70.9%) had specimens that tested positive by means of RT-PCR, serologic testing or both methods. The proportion of RT-PCR test results that were positive was similar between patients who met the criteria for suspect SARS (50.8%, 95% confidence interval [CI] 38.4%-63.2%) and those who met the criteria for probable SARS (58.0%, 95% CI 44.2%-70.7%). SARS-CoV was detected in nasopharyngeal swabs in 33 (32.4%) of 102 patients, in stool specimens in 19 (63.3%) of 30 patients, and in specimens from the lower respiratory tract in 10 (58.8%) of 17 patients. INTERPRETATION: These findings suggest that the rapid diagnostic tests in use at the time of the initial outbreak lack sufficient sensitivity to be used clinically to rule out SARS. As tests for SARS-CoV continue to be optimized, evaluation of the clinical presentation and elucidation of a contact history must remain the cornerstone of SARS diagnosis. In patients with SARS, specimens taken from the lower respiratory tract and stool samples test positive by means of RT-PCR more often than do samples taken from other areas.