Shortening the incubation time for the combination disk diffusion extended-spectrum ß-lactamase (ESBL) confirmation test: how far can we go?

The combination disk diffusion extended-spectrum ß-lactamase (ESBL) confirmation test (CDT) is used for the confirmation of ESBL production in Enterobacteriaceae and usually takes 16-20 h to results. In this study, we searched for the shortest possible incubation time without a reduction in reliability. A total of 125 ESBL screening-positive isolates were subjected to CDT and were molecularly characterised by microarray. Inhibition zones were read every hour over 6-18 h of incubation. Concordance between earlier and 18-h readings was calculated for each hour. Results were validated on 224 isolates during routine clinical practice. For the initial 125 isolates, concordance (Cohen's κ) between the 6-h and 18-h readings was 0.88 [95% confidence interval (CI) 0.78-0.96; P <0.001]. The earliest time point for full concordance with the 18-h reading was 10 h. Validation of the 10-h reading for 224 clinical isolates resulted in a concordance of 0.99 (95% CI 0.98-1.0) between the 10-h and 18-h readings. Overall concordance on all 349 isolates was 0.99 (95% CI 0.97-1.0). Reading after 10 h of incubation has an excellent correlation with results after 18 h of incubation. This can significantly reduce the turnaround time for ESBL detection in laboratories with long opening hours or providing a 24/7 service. Consequently, there is a potential for implementing infection control measures up to 8 h earlier.

Comparison of hepatitis C virus treatment between incarcerated and community patients.

UNLABELLED: The prevalence of chronic hepatitis C virus (HCV) infection among incarcerated individuals in the United States is estimated to be between 12% and 31%. HCV treatment during incarceration is an attractive option because of improved access to health care and directly observed therapy. We compared incarcerated and nonincarcerated HCV-infected patients evaluated for treatment at a single academic center between January 1, 2002 and December 31, 2007. During this period, 521 nonincarcerated and 388 incarcerated patients were evaluated for HCV treatment. Three hundred and nineteen (61.2%) nonincarcerated patients and 234 (60.3%) incarcerated patients underwent treatment with pegylated interferon and ribavirin. Incarcerated patients were more likely to be male, African-American race, and have a history of alcohol or intravenous drug use. Treated incarcerated patients were less likely to have genotype 1 virus and were less likely to have undergone previous treatment. There was a similar prevalence of coinfection with human immunodeficiency virus (HIV) in both groups. A sustained viral response (SVR) was achieved in 97 (42.9%) incarcerated patients, compared to 115 (38.0%) nonincarcerated patients (P = 0.304). Both groups had a similar proportion of patients that completed a full treatment course. Stepwise logistic regression was conducted, and the final model included full treatment course, non-genotype 1 virus, younger age at treatment start, and negative HIV status. Incarceration status was not a significant predictor when added to this model (P = 0.075). CONCLUSION: In a cohort of HCV-infected patients managed in an academic medical center ambulatory clinic, incarcerated patients were as likely to be treated for HCV and as likely to achieve an SVR as nonincarcerated patients.