To the Editor—Sutter Tracy Community Hospital (STCH) is a nonprofit 79-bed acute-care hospital located in Northern California serving more than 100,000 people in the Central Valley region. In 2015, the STCH Antimicrobial Stewardship Program (ASP) established a multidisciplinary committee under the leadership of a consultant ASP physician and an ASP certified pharmacist to coordinate antibiotic stewardship efforts and to support the implementation of new initiatives.

Carbapenems have broad-spectrum activity against gram-positive and gram-negative bacteria, including organisms producing extended spectrum β-lactamases (ESBLs). Unrestricted use and overuse of these agents leads to limited susceptibility profiles and reduced treatment options. Carbapenem-resistant Enterobacteriaceae (CRE) bacteria have been on the rise and have been deemed an urgent threat level by the Centers for Disease Control and Prevention (CDC). More than 9,000 healthcare-associated infections are caused by CRE bacteria each year, with a reported 40–50% mortality rate for invasive infections. ^{1 ,} Reference Livorsi, Chorazy and Schweizer ² An additional serious threat is multidrug-resistant Pseudomonas aeruginosa, which accounts for 13% of all hospital-acquired P. aeruginosa infections. These organisms often exhibit high rates of cross resistance with all β-lactam antibiotics. ^{1 ,} Reference Sader, Huband and Castanheira ³

Promoting the appropriate use of antibiotics by decreasing inappropriate prescribing is a key element of antibiotic stewardship to reduce the emergence of resistance.Reference Barlam, Cosgrove and Abbo ⁴ Studies have shown that unrestricted use of carbapenems have been linked to high rates of inappropriate use, thereby offering opportunities for the selection of narrower-spectrum agents or therapy de-escalation. Pharmacy-driven stewardship efforts have been successful with carbapenem de-escalation, but data demonstrating the direct effect of antibiotic stewardship interventions on improving their susceptibility profiles are lacking.Reference Lai, Shi and Chen ^{5 –} Reference Janssen, Kinkade and Man ⁸

The STCH Antimicrobial Stewardship Committee noted imipenem-cilastatin as the antipseudomonal β-lactam with the lowest susceptibility to P. aeruginosa (88%) and a concerning decreasing trend from previous years (92% in 2013). A Carbapenem Prescribing Algorithm (Fig. 1) was developed as guidance to prescribers to promote the appropriate use of carbapenems. Pharmacists utilized prospective audit and feedback for new orders that failed to meet the algorithm’s use criteria and recommended alternative therapy. The objective of this stewardship initiative was to decrease overall carbapenem use by improving prescribing habits and promoting the appropriate use of these antibiotics. Buy-in was obtained from hospital physicians at the Department of Medicine committee meeting prior to implementation.

Fig. 1

Carbapenem Prescribing Algorithm