Performance characteristics of SARS-CoV-2 nucleic acid detection assays are understudied within contexts of low pre-test probability, including screening asymptomatic persons without epidemiological links to confirmed cases, or asymptomatic surveillance testing. SARS-CoV-2 detection without symptoms may represent presymptomatic or asymptomatic infection, resolved infection with persistent RNA shedding, or a false-positive test. This study assessed the positive predictive value of SARS-CoV-2 real-time reverse transcription polymerase chain reaction (rRT-PCR) assays by retesting positive specimens from 5 pre-test probability groups ranging from high to low with an alternate assay.

In total, 122 rRT-PCR positive specimens collected from unique patients between March and July 2020 were retested using a laboratory-developed nested RT-PCR assay targeting the RNA-dependent RNA polymerase (RdRp) gene followed by Sanger sequencing.

Significantly fewer (15.6%) positive results in the lowest pre-test probability group (facilities with institution-wide screening having ≤3 positive asymptomatic cases) were reproduced with the nested RdRp gene RT-PCR assay than in each of the 4 groups with higher pre-test probability (individual group range, 50.0%–85.0%).

Large-scale SARS-CoV-2 screening testing initiatives among low pre-test probability populations should be evaluated thoroughly prior to implementation given the risk of false-positive results and consequent potential for harm at the individual and population level.

Carbapenemase-producing Enterobacteriaceae (CPE) pose a significant global health threat.

To conduct a systematic review of health outcomes and long-term sequelae attributable to CPE infection.

We followed PRISMA reporting guidelines and published our review protocol on PROSPERO (CRD42018097357). We searched Medline, Embase, CINAHL and the Cochrane Library. We included primary studies with a carbapenem-susceptible control group in high-income countries, published in English. Quality appraisal was completed using Joanna Briggs Institute checklists. We qualitatively summarized frequently reported outcomes and conducted a meta-analysis.

Our systematic review identified 8,671 studies; 17 met the eligibility criteria for inclusion. All studies reported health outcomes; none reported health-related quality-of-life. Most studies were from Europe (65%), were conducted in teaching or university-affiliated hospitals (76%), and used case-control designs (53%). Mortality was the most commonly reported consequence of CPE-infections; in-hospital mortality was most often reported (62%). Our meta-analysis (n = 5 studies) estimated an absolute risk difference (ARD) for in-hospital bloodstream infection mortality of 0.25 (95% confidence interval [CI], 0.17–0.32). Duration of antibiotic therapy (range, 4–29.7 vs 1–23.6 days) and length of hospital stay (range, 21–87 vs 15–43 days) were relatively higher for CPE-infected patients than for patients infected with carbapenem-susceptible pathogens. Most studies (82%) met >80% of their respective quality appraisal criteria.

The risk of in-hospital mortality due to CPE bloodstream infection is considerably greater than carbapenem-susceptible bloodstream infection (ARD, 0.25; 95% CI, 0.17–0.32). Health outcome studies associated with CPE infection are focused on short-term (eg, in-hospital) outcomes; long-term sequelae and quality-of-life are not well studied.

PROSPERO (CRD42018097357).