Publications

Urogenital Neisseria gonorrhoeae isolates (266) collected in San Francisco, CA, in 2009 were analyzed for antimicrobial susceptibility and were subsequently genotyped by N. gonorrhoeae multiantigen sequence typing (NG-MAST). Isolates of identical or closely related sequence types were found to possess highly similar phenotypes with regard to drug susceptibility. Isolates containing decreased susceptibility to oral cephalosporins were detected in 2009 and were found to contain the mosaic penA allele (XXXIV) found previously to be associated with decreased susceptibility to cephalosporins. A better understanding of the relationships between phenotypic and genotypic markers for antimicrobial resistance may be helpful to the development of effective surveillance systems for drug-resistant N. gonorrhoeae.

BACKGROUND

Low-risk chest pain is a common cause of hospital admission; however, to our knowledge, there are no guidelines regarding the appropriate use of stress testing in such cases.

METHODS

We performed a retrospective cohort study of patients 21 years and older who were admitted to our tertiary care center with chest pain in 2007 and 2008. Using electronic records and chart review, we sought (1) to identify differences in the use of stress testing based on patient demographics and comorbidities, pretest probability of coronary artery disease, and house staff coverage and (2) to describe the results of stress testing and patient outcomes, including revascularization procedures and 30-day readmissions for myocardial infarction.

RESULTS

Of 2107 patients, 1474 (69.9%) underwent stress tests, and the results were abnormal in 184 patients (12.5%). Within 30 days, 22 patients (11.6%) with abnormal test results underwent cardiac catheterization, 9 (4.7%) underwent revascularization, and 2 (1.1%) were readmitted for myocardial infarction. In a multivariable model, stress test ordering was positively associated with age younger than 70 years (RR [relative risk], 1.12; 95% CI, 1.02-1.23), private insurance (vs Medicare/Medicaid: RR, 1.19; 95% CI, 1.11-1.27), and no house staff coverage (RR, 1.39; 95% CI, 1.28-1.50). Of patients with low (<10%) pretest probability, 68.0% underwent stress testing, but only 4.5% of these had abnormal test results.

CONCLUSIONS

Most patients who are admitted with low-risk chest pain undergo stress testing, regardless of pretest probability, but abnormal test results are uncommon and rarely acted on. Ordering stress tests based on pretest probability could improve efficiency without endangering patients.

We present a novel and simple method for amplifying RNA targets (named by its acronym, SMART), and for detection, using engineered amplification probes that overcome existing limitations of current RNA-based technologies. This system amplifies and detects optimal engineered ssDNA probes that hybridize to target RNA. The amplifiable probe-target RNA complex is captured on magnetic beads using a sequence-specific capture probe and is separated from unbound probe using a novel microfluidic technique. Hybridization sequences are not constrained as they are in conventional target-amplification reactions such as nucleic acid sequence amplification (NASBA). Our engineered ssDNA probe was amplified both off-chip and in a microchip reservoir at the end of the separation microchannel using isothermal NASBA. Optimal solution conditions for ssDNA amplification were investigated. Although KCl and MgCl(2) are typically found in NASBA reactions, replacing 70 mmol/L of the 82 mmol/L total chloride ions with acetate resulted in optimal reaction conditions, particularly for low but clinically relevant probe concentrations (≤100 fmol/L). With the optimal probe design and solution conditions, we also successfully removed the initial heating step of NASBA, thus achieving a true isothermal reaction. The SMART assay using a synthetic model influenza DNA target sequence served as a fundamental demonstration of the efficacy of the capture and microfluidic separation system, thus bridging our system to a clinically relevant detection problem.