Browsing by Author "Kundu, Madan G."

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    The Effect of Contact Precautions for MRSA on Patient Satisfaction Scores
    (Elsevier, 2015-07) Livorsi, Daniel J.; Kundu, Madan G.; Batteiger, Byron; Kressel, Amy B.; Department of Medicine, IU School of Medicine
    Contact precautions may have an adverse effect on a patient's hospital experience and the delivery of care. This case–control study compared patient satisfaction scores between 70 patients isolated for MRSA and 139 non-isolated patients. Based on an adjusted analysis, there was no difference in patient satisfaction between the two groups. Age and educational status were found to affect patient satisfaction.
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    Methicillin-Resistant Staphylococcus aureus (MRSA) Nasal Real-Time PCR: A Predictive Tool for Contamination of the Hospital Environment
    (Cambridge, 2015-01) Livorsi, Daniel J.; Arif, Sana; Garry, Patricia; Kundu, Madan G.; Satola, Sarah W.; Davis, Thomas H.; Batteiger, Byron; Kressel, Amy B.; Department of Medicine, IU School of Medicine
    OBJECTIVE We sought to determine whether the bacterial burden in the nares, as determined by the cycle threshold (CT) value from real-time MRSA PCR, is predictive of environmental contamination with MRSA. METHODS Patients identified as MRSA nasal carriers per hospital protocol were enrolled within 72 hours of room admission. Patients were excluded if (1) nasal mupirocin or chlorhexidine body wash was used within the past month or (2) an active MRSA infection was suspected. Four environmental sites, 6 body sites and a wound, if present, were cultured with premoistened swabs. All nasal swabs were submitted for both a quantitative culture and real-time PCR (Roche Lightcycler, Indianapolis, IN). RESULTS At study enrollment, 82 patients had a positive MRSA-PCR. A negative correlation of moderate strength was observed between the CT value and the number of MRSA colonies in the nares (r=−0.61; P<0.01). Current antibiotic use was associated with lower levels of MRSA nasal colonization (CT value, 30.2 vs 27.7; P<0.01). Patients with concomitant environmental contamination had a higher median log MRSA nares count (3.9 vs 2.5, P=0.01) and lower CT values (28.0 vs 30.2; P<0.01). However, a ROC curve was unable to identify a threshold MRSA nares count that reliably excluded environmental contamination. CONCLUSIONS Patients with a higher burden of MRSA in their nares, based on the CT value, were more likely to contaminate their environment with MRSA. However, contamination of the environment cannot be predicted solely by the degree of MRSA nasal colonization.
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    On information fraction for Fleming‐Harrington type weighted log‐rank tests in a group‐sequential clinical trial design
    (Wiley, 2021-05) Kundu, Madan G.; Sarkar, Jyotirmoy; Mathematical Sciences, School of Science
    When comparing survival times of treatment and control groups under a more realistic nonproportional hazards scenario, the standard log-rank (SLR) test may be replaced by a more efficient weighted log-rank (WLR) test, such as the Fleming-Harrington (FH) test. Designing a group-sequential clinical trial with one or more interim looks during which a FH test will be performed, necessitates correctly quantifying the information fraction (IF). For SLR test, IF is defined simply as the ratio of interim to final numbers of events; but for FH test, it can deviate substantially from this ratio. In this article, we separate the effect of weight function (of FH test) alone on IF from the effect of censoring. We have shown that, without considering the effect of censoring, IF can be derived analytically for FH test using information available at the design stage and the additional effect due to censoring is relatively smaller. This article intends to serve two major purposes: first, to emphasize and rationalize the deviation of IF in weighted log-rank test from that of SLR test which is often overlooked (Jiménez, Stalbovskaya, and Jones); second, although it is impossible to predict IF for a weighted log-rank test at the design stage, our decomposition of effects on IF provides a reasonable and practically feasible range of IF to work with. We illustrate our approach with an example and provide simulation results to evaluate operating characteristics.