The study objective was to develop and validate a clinical decision support system (CDSS) to guide clinicians through the diagnostic evaluation of hospitalized individuals with suspected pulmonary tuberculosis (TB) in low-prevalence settings.

The “TBorNotTB” CDSS was developed using a modified Delphi method. The CDSS assigns points based on epidemiologic risk factors, TB history, symptoms, chest imaging, and sputum/bronchoscopy results. Below a set point threshold, airborne isolation precautions are automatically discontinued; otherwise, additional evaluation, including infection control review, is recommended. The model was validated through retrospective application of the CDSS to all individuals hospitalized in the Mass General Brigham system from July 2016 to December 2022 with culture-confirmed pulmonary TB (cases) and equal numbers of age and date of testing-matched controls with three negative respiratory mycobacterial cultures.

104 individuals with TB (cases) and 104 controls were identified. Prior residence in a highly endemic country, positive interferon release assay, weight loss, absence of symptom resolution with treatment for alternative diagnoses, and findings concerning for TB on chest imaging were significant predictors of TB (all P < 0.05). CDSS contents and scoring were refined based on the case–control analysis. The final CDSS demonstrated 100% sensitivity and 27% specificity for TB with an AUC of 0.87.

The TBorNotTB CDSS demonstrated modest specificity and high sensitivity to detect TB even when AFB smears were negative. This CDSS, embedded into the electronic medical record system, could help reduce risks of nosocomial TB transmission, patient-time in airborne isolation, and person-time spent reviewing individuals with suspected TB.

Many studies have investigated the association between prior antibiotic use and antibiotic resistance. However, methods used in past studies to describe the extent of prior antibiotic use (eg, use of the 2 categories exposure versus no exposure and measurement of duration of exposure) have not been reviewed. The impact of the use of different methods for quantifying the use of antibiotics is unknown. The objectives of this study were to characterize past approaches to describing the extent of antibiotic use and to identify the impact of the use of different methods on associations between use of specific antibiotics and infection with an antibiotic-resistant-organism.

We conducted a systematic review of studies that investigated risk factors for extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella species to identify variability in past approaches to describing the extent of antibiotic use. We then reanalyzed a data set from a prior study of risk factors for infection with ESBL-producing E. coli and Klebsiella species. We developed 2 separate multivariable models: 1 in which prior antibiotic use was described as a categorical variable (eg, exposure or no exposure) and 1 in which antibiotic use was described as a continuous variable (eg, measured in antibiotic-days). These models were compared qualitatively.

Large academic medical center.

The 25 articles included in the systematic review revealed a variety of methods used to describe the extent of prior antibiotic exposure. Only 1 study justified its approach. Results from the 2 multivariable models that used different methodologic approaches differed substantially. Specifically, use of third-generation cephalosporins was a risk factor for infection with ESBL-producing E. coli and Klebsiella species when antibiotic use was described as a continuous variable but not when antibiotic use was described as a categorical variable.

There has been no consistent method for assessing the extent of prior antibiotic exposure. The use of different methods may substantially alter the identified antimicrobial risk factors, which has important implications for the resultant interventions regarding antimicrobial use.

Effective methods to control the emergence of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella species (ESBL-EK) remain unclear. Variations in the patient populations at different hospitals may influence the effect of antimicrobial formulary interventions.

To examine variations across hospitals in the response to antimicrobial interventions (ie, restriction of ceftazidime and ceftriaxone) designed to curb the spread of ESBL-EK, we conducted a 5-year quasi-experimental study. This study was conducted at 2 hospitals within the same health system: Hospital A is a 625-bed academic medical center, and Hospital B is a 344-bed urban community hospital. All adult patients with a healthcare-acquired clinical culture of ESBL-EK from July 1, 1997 through December 31, 2002 were included.

After the interventions, the use of ceftriaxone decreased by 86% at Hospital A and by 95% at Hospital B, whereas the use of ceftazidime decreased by 95% at Hospital A and by 97% at Hospital B. The prevalence of ESBL-EK at Hospital A decreased by 45% (P< .001), compared with a 22% decrease at Hospital B (P = .36). The following variables were significantly more common among ESBL-EK-infected patients at Hospital B: residence in a long-term care facility (adjusted odds ratio, 3.77 [95% confidence interval, 1.70-8.37]), advanced age (adjusted odds ratio, 1.04 [95% confidence interval, 1.01-1.06]), and presence of a decubitus ulcer (adjusted odds ratio, 4.13 [95% confidence interval, 1.97-8.65]).

The effect of antimicrobial formulary interventions intended to curb emergence of ESBL-EK may differ substantially across institutions, perhaps as a result of differences in patient populations. Variability in the epidemiological profiles of ESBL-EK isolates at different hospitals must be considered when designing interventions to respond to these pathogens.