Battle of the mnemonics, SPACE versus HECK-Yes! A cross-sectional, nationwide survey of infectious diseases clinicians to evaluate clinical and microbiologic practice patterns for infections caused by Enterobacterales at risk of inducible AmpC produc

Abstract Background Enterobacterales considered at risk of inducible AmpC production are denoted by mnemonics including SPACE and HECK-Yes! However, these mnemonics may fail to account for the variability in AmpC induction potential, which lends to variation in antibiotics chosen for management of associated infections and susceptibility reporting. This study aimed to evaluate clinical and microbiologic practice patterns for the management of infections caused by Enterobacterales at risk of inducible AmpC production. Methods This cross-sectional survey was developed by a multidisciplinary infectious diseases (ID) team and distributed via ID-related listservs (November-December 2024). The survey assessed institutional demographics, β-lactam of choice, and microbiologic reporting for Enterobacterales with a moderate risk (Enterobacter cloacae complex, Klebsiella aerogenes, Citrobacter freundii) and low risk (Serratia marcescens, Morganella morganii, Providencia spp.) of inducible AmpC production. Results Of 94 complete responses, most were from pharmacists (58.5%) and physicians (38.3%) working in adult academic medical centres (39.4%) or community hospitals (37.2%). Cefepime was the preferred β-lactam for invasive (87.2%) and non-invasive (68.1%) infections caused by moderate-risk inducible AmpC producers, while ceftriaxone was preferred for invasive (57.4%) and non-invasive (60.7%) infections caused by low-risk inducible AmpC Inducers. Cefepime (98.8% versus 98.8%), meropenem (85.5% versus 83.1%), piperacillin/tazobactam (72.3% versus 83.1%), and ceftriaxone (67.5% versus 94.0%) were commonly reported antibiotics on non-urinary antibiograms for moderate risk and low risk Enterobacterales, respectively. The beta-lactams reported in institutional antibiograms and microbiology susceptibility reporting were generally similar. Conclusions This survey highlights differences in practice patterns for management of infections caused by inducible AmpC-producing Enterobacterales. These results emphasize the importance of standardized, evidence-based antimicrobial stewardship approaches and continued clinical investigation to better optimize therapy for infections caused by Enterobacterales capable of inducible AmpC production.