Janet Y. Nakase

Etiology of Bloody Diarrhea among Patients Presenting to United States Emergency Departments: Prevalence of Escherichia coli O157:H7 and Other Enteropathogens

Escherichia coli O157:H7 and other Shiga toxin-producing E. coli (STEC) infections have been associated with bloody diarrhea. The prevalence of enteropathogens among patients with bloody diarrhea was determined by a prospective study at 11 US emergency departments. Eligible patients had bloody stools, > or =3 loose stool samples per 24-h period, and an illness lasting <7 days. Among 873 patients with 877 episodes of bloody diarrhea, stool samples for culture were obtained in 549 episodes (62.6%). Stool cultures were more frequently ordered for patients with fever, >10 stools/day, and visibly bloody stools than for patients without these findings. Enteropathogens were identified in 168 episodes (30.6%): Shigella (15.3%), Campylobacter (6.2%), Salmonella (5.8%), STEC (2.6%), and other (1.6%). Enteropathogens were isolated during 12.5% of episodes that physicians thought were due to a noninfectious cause. The prevalence of STEC infection varied by site from 0% to 6.2%. Hospital admissions resulted from 195 episodes (23.4%). These data support recommendations that stool samples be cultured for patients with acute bloody diarrhea.

Decision Instrument for the Isolation of Pneumonia Patients With Suspected Pulmonary Tuberculosis Admitted Through US Emergency Departments

STUDY OBJECTIVE Many patients with pneumonia are admitted to respiratory isolation for possible tuberculosis (TB), but most do not have active TB. We created a decision instrument to predict which pneumonia patients do not need admission to a TB isolation bed. METHODS The design was a prospective case series conducted in 11 university-affiliated, urban, US emergency departments (EDs) (EMERGEncy ID NET). Participants were patients admitted to the hospital through the ED with a diagnosis of pneumonia or suspected TB. The main outcome measure was derivation and validation of a sensitive decision instrument to identify patients not having TB (and not requiring isolation) according to clinical data and chest radiographs. RESULTS Of 5,079 pneumonia patients, 224 (4.4%) had pulmonary TB according to sputum cultures or tissue staining. The instrument derived to predict which patients did not have pulmonary TB included no TB history or previous positive tuberculin skin test result, nonimmigrant, not homeless, not recently incarcerated, no recent weight loss, and no apical infiltrate or cavitary lesion on plain chest radiograph. When tested on the validation subgroup, the decision instrument exhibited a negative predictive value of 99.7% (95% confidence interval [CI] 99.1% to 99.9%), and a sensitivity of 96.4% (95% CI 91.1% to 99.0%). CONCLUSION A decision instrument can accurately predict which patients with pneumonia do not require admission to TB isolation rooms.