December 10, 2018
2 min read

Each day of antibiotic exposure increases risk for resistance

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

We were unable to process your request. Please try again later. If you continue to have this issue please contact

Besu F. Teshome, PharmD, MSc, BCPS
Besu F. Teshome

Each additional day of exposure to antibiotics increases the risk for the development of new resistance, retrospective study findings published in Pharmacotherapy showed.

“We retrospectively evaluated critically ill adults who received an antipseudomonal beta-lactam antibiotic — specifically cefepime, meropenem, or piperacillin-tazobactam — during hospitalization to see if there was an association with the duration of antibiotic exposure and development of new resistance to the exposed antibiotic in the subsequent 60 days,” Besu F. Teshome, PharmD, MSc, BCPS, assistant professor of pharmacy practice at the St. Louis College of Pharmacy, explained to Infectious Disease News.

Teshome and colleagues conducted the single-center, retrospective cohort study at Barnes-Jewish Hospital in St. Louis between Jan. 1, 2010, and Dec. 31, 2015. Using the hospital’s electronic medical record system, they assessed 7,118 adults aged 18 years or older with a discharge diagnosis of severe sepsis or septic shock who received at least one dose of cefepime, meropenem or piperacillin-tazobactam during their hospitalization.

They described the primary outcome as the development of new resistance to antipseudomonal beta-lactams observed more than 3 days after cohort entry, with new resistance being defined as a resistance to any antipseudomonal beta-lactam that had not been detected 180 days before cohort entry. Secondary outcomes involved evaluating each antipseudomonal beta-lactam.

Most of the 7,718 patients had at least one dose of cefepime (n = 5,274), whereas patients who had at least one dose of meropenem and piperacillin-tazobactam totaled 3,635 and 2,463, respectively.

According to Teshome and colleagues, each additional day of exposure to any antipseudomonal beta-lactam was associated with an increased risk for new resistance development (adjusted HR = 1.04; 95% CI, 1.04-1.05). Individually, each additional day of exposure to cefepime, meropenem or piperacillin-tazobactam also was associated with an increased risk for developing a new resistance, with reported aHRs of 1.08 (95% CI, 1.07-1.09), 1.02 (95% CI, 1.01-1.03) and 1.08 (95% CI, 1.06-1.09), respectively.

“Each additional day of antibiotic exposure is associated with an increased risk of resistance development, regardless of the appropriateness of use,” Teshome said. “These findings highlight the importance of staying vigilant against inappropriate antibiotic initiation, as well as clinicians taking a more active role to reassess the appropriateness of antibiotics on a daily basis to limit exposure to the shortest effective duration.” – by Marley Ghizzone

Disclosures: Teshome reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.