1996. Enteric Multiplex PCR Testing: Antimicrobial Stewardship Friend or Foe

BACKGROUND: There are advantages and challenges associated with enteric multiplex PCR testing. Fast turnaround time can lead to prompt pathogen identification and antibiotic initiation, decreased length of stay and decreased time in isolation. Challenges include identification of multiple organisms, carrier state detection, and detection of organisms with uncertain pathogenic potential, which can lead to unnecessary antibiotic use. METHODS: Two institutions transitioned from stool culture to stool PCR testing for identification of diarrheal pathogens. On February 1, 2016, Center 1 employed the BioFire® FilmArray® GI Panel, which detects 22 organisms and includes targets of unclear clinical significance. Center 2 implemented the BD MAX™ Enteric Bacterial Panel on 3/6/2019, which reports 4 bacterial known pathogens. Fluoroquinolone (FQ) and third-generation cephalosporin (TGC) prescribing in response to positive PCR testing was assessed over a 1 month period. Antibiotics were counted when prescribed within 72 hours of the collection date. RESULTS: At Center 1, 332 GI PCR panels were ordered, 94 (28.3%) were positive and 15 (16%) were treated; 4 received an FQ (26%), and 11 (73%) received a TGC. Center 1 organisms included 44 Clostridioides difficile, 27 Norovirus, 8 Enteropathogenic E. coli, 7 Sapovirus, 4 Campylobacter species, 2 Giardia lamblia, 2 Rotavirus, 1 Shigella/Enteroinvasive E. coli and 1 Salmonella species. Of 642 PCR tests ordered at Center 2, 16 (2.5%) were positive and 11 (69%) were treated; 10 (91%) received a FQ, and 1 (9%) received a TGC. Center 2 organisms included 8 non-typhoidal Salmonella species, 5 Aeromonas species, 2 Shigella sonnei and 1 Salmonella typhi. CONCLUSION: Implementation of an enteric multiplex PCR test with targets of uncertain clinical significance is more likely to yield an abnormal result than a PCR test with only known pathogens. However, careful interpretation of results can avoid unnecessary antimicrobial use. Antimicrobial stewardship teams should work in tandem with microbiology laboratories to implement enteric multiplex PCR tests and monitor the impact on antibiotic use. Larger studies are needed to definitively assess the impact of the GI panel on antimicrobial prescribing within the context of patient comorbidities and institutional practices. DISCLOSURES: All authors: No reported disclosures.