We sought to define the prevalence of tuberculin skin test (TST) positivity in a group of newly hospitalized patients, to identify risk factors for positive tests, and to examine the impact of testing on infection control practices.

Unblinded cohort study over 5 days in July 1992.

A 1,000-bed university-affiliated hospital.

All patients admitted (excluding obstetric patients and newborns) were interviewed. Patients without a history of tuberculosis (TB) or a positive TST were offered a TST with Candida and tetanus controls.

Of 346 patients offered the test, 21 (6%) had a prior history of TB or a positive TST, and 36 (10%) declined to participate; 279 of the remaining 289 completed the study. Anergy was demonstrated in 94 (33.7%) of 279 patients. New positive TSTs were identified in 19 (10.3%) of 185 nonanergic patients. Of the 19 TST-positive patients, 6 (32%) had infiltrates on chest radiographs and were evaluated for active TB. One patient was treated empirically for active TB, and five received isoniazid prophylaxis. Risk factors for a new positive TST included age (odds ratio [OR], 1.56 per decade of life; P=.021), African American race (OR, 4.81; P=.008), alcohol abuse (OR, 5.53; P=.005), and peptic ulcer disease (OR, 4.53; P=.017). Risk factors for anergy included admission to a surgical service (OR, 2.1; P=.006), current use of steroids (OR, 2.65; P=.005), and human immunodeficiency virus (HIV) infection (OR, undefined; P=.034).

Despite a high rate of anergy, routine tuberculin skin testing identified a substantial number of patients with TB infection who might otherwise have gone unrecognized.

To describe OXA-48–like carbapenem-producing Enterobacteriaceae (CPE) outbreaks at Singapore General Hospital between 2018 and 2020 and to determine the risk associated with OXA-48 carriage in the 2020 outbreak.

Outbreak report and case–control study.

Singapore General Hospital (SGH) is a tertiary-care academic medical center in Singapore with 1,750 beds.

Active surveillance for CPE is conducted for selected high-risk patient cohorts through molecular testing on rectal swabs or stool samples. Patients with CPE are isolated or placed in cohorts under contact precautions. During outbreak investigations, rectal swabs are repeated for culture. For the 2020 outbreak, a retrospective case–control study was conducted in which controls were inpatients who tested negative for OXA-48 and were selected at a 1:3 case-to-control ratio.

Hospital wide, the median number of patients with healthcare-associated OXA-48 was 2 per month. In the 3-year period between 2018 and 2020, 3 OXA-48 outbreaks were investigated and managed, involving 4 patients with Klebsiella pneumoniae in 2018, 55 patients with K. pneumoniae or Escherichia coli in 2019, and 49 patients with multispecies Enterobacterales in 2020. During the 2020 outbreak, independent risk factors for OXA-48 carriage on multivariate analysis (49 patients and 147 controls) were diarrhea within the preceding 2 weeks (OR, 3.3; 95% CI, 1.1–10.7; P = .039), contact with an OXA-48–carrying patient (OR, 8.7; 95% CI, 1.9–39.3; P = .005), and exposure to carbapenems (OR, 17.2; 95% CI, 2.2–136; P = .007) or penicillin (OR, 16.6; 95% CI, 3.8–71.0; P < .001).

Multispecies OXA-48 outbreaks in our institution are likely related to a favorable ecological condition and selective pressure exerted by antimicrobial use. The integration of molecular surveillance epidemiology of the healthcare environment is important in understanding the risk of healthcare–associated infection to patients.