1458. A Single Center Quasi-Experimental Study to Evaluate the Impact of Utilizing Rapid Diagnostic Technology to Detect Methicillin-Resistant Staphylococcus aureus in Respiratory Culture Samples
Session: Poster Abstract Session: Respiratory Infections: CAP
Friday, October 5, 2018
Room: S Poster Hall

Methicillin-resistant Staphylococcus aureus (MRSA) is a relevant pathogen for patients with pneumonia in the presence of certain risk factors. Empiric broad-spectrum antimicrobial therapy, including anti-MRSA therapy, is frequently initiated in patients hospitalized with pneumonia. The low yield of respiratory cultures makes antimicrobial de-escalation difficult, potentially leading to extended durations of anti-MRSA therapy and increasing risk for significant drug-related adverse effects. A polymerase chain reaction (PCR) test that was previously utilized for nasal MRSA screening was internally validated to identify the presence of MRSA in respiratory specimens within 2 hours of sample collection. The primary objective of this study was to determine the effect of this respiratory PCR test on duration of anti-MRSA therapy in non-intensive care unit (ICU) patients hospitalized with pneumonia.


Implementation of the PCR test in non-ICU units occurred Dec 1, 2017. During the post-intervention (INT) period (Dec 1, 2017 – Mar 31, 2018), PCR results were evaluated daily by antimicrobial stewardship and decentralized staff pharmacists for therapy de-escalation opportunities, with recommendations communicated to prescribers. The pre-INT group (Dec 1, 2016 – Mar 31, 2017) consisted of non-ICU patients hospitalized with pneumonia who received anti-MRSA therapy for at least 48 hours, or who qualified for anti-MRSA therapy per institutional guidelines.


A total of 169 patients were evaluated; 109 in the post-INT group and 60 in the pre-INT group. Anti-MRSA therapy was administered to 74 patients (68%) in the post-INT group, compared to 56 patients (93%) in the pre-INT group. The median duration of anti-MRSA therapy post-INT was 23.5 hours, which was significantly shorter than the pre-INT duration of 55.5 hours (p<0.0001). The post-INT group also had significantly less vancomycin-induced nephrotoxicity (p<0.0383) and a shorter time to targeted therapy (p<0.0001). No difference in 30 day all-cause mortality was observed (p<0.1338).


Utilization of a PCR test to detect MRSA in respiratory specimens decreased duration of anti-MRSA therapy in non-ICU patients hospitalized with pneumonia.

Kelsey Olson, PharmD1, Sara Revolinski, PharmD, BCPS2, J Njeri Wainaina, MD2, Jessica Luzi, PharmD1 and Angela Huang, PharmD, BCPS-AQ ID2, (1)Pharmacy, Froedtert & The Medical College of Wisconsin, Milwaukee, WI, (2)Froedtert & The Medical College of Wisconsin, Milwaukee, WI


K. Olson, None

S. Revolinski, None

J. N. Wainaina, None

J. Luzi, None

A. Huang, None

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