Utility of beta-lactam allergy assessment in patients receiving vancomycin for surgical prophylaxis.

Background: Beta-lactam antibiotics are first-line agents for most patients receiving antimicrobial prophylaxis in surgical procedures. Despite evidence showing low cross-reactivity between penicillins and cephalosporins, patients with beta-lactam allergies commonly receive vancomycin as an alternative to avoid allergic reaction. Methods: Adult patients receiving vancomycin for surgical prophylaxis with a reported beta-lactam allergy at our institution between August 2017 to July 2018 were retrospectively evaluated for potential eligibility for penicillin allergy testing and/or receipt of standard prophylaxis. Results: Among 830 patients who received vancomycin for surgical prophylaxis, 196 reported beta-lactam allergy and were included in the analysis. Approximately 40 % of surgeries were orthopedic. Of patients receiving vancomycin as first-line therapy, 189 (96.4 %) were potentially eligible for beta-lactam prophylaxis. Conclusions: Patients with beta-lactam allergies often qualify for receipt of a first-line antibiotic. An opportunity exists for improved allergy assessment as an antimicrobial stewardship intervention in surgical prophylaxis.

Influence of Antibiotic Exposure Intensity on the Risk of Clostridioides difficile Infection.

BACKGROUND: Antibiotics are a strong risk factor for Clostridioides difficile infection (CDI), and CDI incidence is often measured as an important outcome metric for antimicrobial stewardship interventions aiming to reduce antibiotic use. However, risk of CDI from antibiotics varies by agent and dependent on the intensity (i.e., spectrum and duration) of antibiotic therapy. Thus, the impact of stewardship interventions on CDI incidence is variable, and understanding this risk requires a more granular measure of intensity of therapy than traditionally used measures like days of therapy (DOT). METHODS: We performed a retrospective cohort study to measure the independent association between intensity of antibiotic therapy, as measured by the antibiotic spectrum index (ASI), and hospital-associated CDI (HA-CDI) at a large academic medical center between January 2018 and March 2020. We constructed a marginal Poisson regression model to generate adjusted relative risks for a unit increase in ASI per antibiotic day. RESULTS: We included 35,457 inpatient encounters in our cohort. Sixty-eight percent of patients received at least one antibiotic. We identified 128 HA-CDI cases, which corresponds to an incidence rate of 4.1 cases per 10,000 patient-days. After adjusting for known confounders, each additional unit increase in ASI per antibiotic day is associated with 1.09 times the risk of HA-CDI (Relative Risk = 1.09, 95% Confidence Interval: 1.06 to 1.13). CONCLUSIONS: ASI was strongly associated with HA-CDI and could be a useful tool in evaluating the impact of antibiotic stewardship on HA-CDI rates, providing more granular information than the more commonly used days of therapy.

General Perceptions and Knowledge of Antibiotic Resistance and Antibiotic Use Behavior: A Cross-Sectional Survey of US Adults.

This study aimed to assess understanding of antibiotic resistance and evaluate antibiotic use themes among the general public. In March 2018, respondents that were ≥21 years old and residing in the United States were recruited from ResearchMatch.org and surveyed to collect data on respondent expectations, knowledge, and opinions regarding prescribing antibiotics and antibiotic resistance. Content analysis was used to code open-ended definitions of antibiotic resistance into central themes. Chi-square tests were used to assess differences between the definitions of antibiotic resistance and antibiotic use. Among the 657 respondents, nearly all (99%) had taken an antibiotic previously. When asked to define antibiotic resistance, the definitions provided were inductively coded into six central themes: 35% bacteria adaptation, 22% misuse/overuse, 22% resistant bacteria, 10% antibiotic ineffectiveness, 7% body immunity, and 3% provided an incorrect definition with no consistent theme. Themes that were identified in respondent definitions of resistance significantly differed between those who reported having shared an antibiotic versus those who had not (p = 0.03). Public health campaigns remain a central component in the fight to combat antibiotic resistance. Future campaigns should address the public's understanding of antibiotic resistance and modifiable behaviors that may contribute to resistance.

Infectious complications of probiotic use: A matched case-control study.

In this matched case-control study, we sought to determined the association between probiotic use and invasive infections caused by typical probiotic organisms. The odds of probiotic use in cases were 127 times the odds of probiotic use in controls (95% CI, 6.21-2600). Further research into these rare but severe complications is needed.

Safety and efficacy of direct two-step penicillin challenges with an inpatient pharmacist-driven allergy evaluation.

Background: Penicillin allergy is commonly reported and has clinical and financial consequences for patients and hospitals. A penicillin evaluation program can safely delabel patients and optimize antibiotic therapy. Pharmacists who perform this task have focused on a detailed interview or penicillin skin testing (PST). Antibiotic graded challenge after PST requires more resources and is more costly than going directly to a two-step challenge. Objective: To determine whether a pharmacist-driven penicillin allergy evaluation and a testing protocol that primarily uses direct oral challenges can safely delabel patients. Methods: Adult patients (ages >18 years) with a penicillin allergy in their electronic medical record (EMR) who were admitted between September 2019 and June 2020 were eligible. Although all patients with penicillin allergy were eligible, priority was given to patients who required antibiotics. Patients were interviewed, and, if indicated, based on an institutional protocol, were tested by using PST and/or two-step oral challenge. If the patient passed the challenge, then the penicillin allergy label was removed in the EMR and the patient counseled. Demographic information, allergy questionnaire results, testing results, and changes in antimicrobial therapy were collected. Results: Fifty patients were evaluated from September 2019 to June 2020. Ninety-six percent of the patients were delabeled, and antibiotic therapy changed for 54%. Twenty patients were delabeled with an interview alone, and 30 patients underwent oral two-step challenge. Only one patient required PST. Conclusion: A pharmacist-driven penicillin allergy evaluation program focused on direct oral graded challenges and bypassing PST can effectively delabel admitted patients. However, more safety data are needed before implementation of similar programs to optimize antibiotic treatment.

A Single-Center Evaluation of Extended Infusion Piperacillin/Tazobactam for Empiric Treatment in the Intensive Care Unit.

Background: Piperacillin/tazobactam (PTZ) extended infusion (EI) is often used empirically in the intensive care unit (ICU). Gram-negative (GN) organisms with PTZ minimum inhibitory concentrations (MICs) >16/4 µg/mL are considered intermediate or resistant. Objective: The objective of this study was to evaluate MICs of GN isolates from the ICU to determine whether the hospital protocol for PTZ 3.375 g EI over 4 hours administered every 8 hours is an appropriate empiric regimen for ICU patients and to evaluate patient-specific risk factors associated with elevated MICs. Methods: All ICU patients admitted during 2017 with a confirmed GN organism from a non-urinary source were included for retrospective chart review. Patients with cystic fibrosis or cultures obtained >48 hours prior to ICU admission were excluded. Demographics, GN organism, culture source, risk factors for resistance, susceptibility profile, comorbidities, and creatinine clearance were collected. Appropriateness was defined as PTZ MIC ≤16/4 µg/mL in >80% of isolates. Results: Two hundred and thirty-one patients were included. The average patient was 56 years old. The majority of patients were white (64.1%) and male (69.7%). Pseudomonas aeruginosa (41%) was the most common organism isolated. Overall, 28% of GN isolates had MICs >16/4 µg/mL. Dialysis (P = .01), intravenous antibiotics within 90 days (P < .001), and presence of wounds/trauma (P = .01) were associated with elevated MICs. Conclusion: Current PTZ EI 3.375 g dosing regimens may not provide adequate empiric coverage for some GN organisms in ICU patients, especially for those who have previously received intravenous antibiotics, are on dialysis, or have wounds/trauma.

Syndrome-specific versus prospective audit and feedback interventions for reducing use of broad-spectrum antimicrobial agents.

BACKGROUND: Antimicrobial use (AU) of antipseudomonal ß-lactams (APBL) has significantly increased over the past decade in US hospitals. This retrospective cohort study compares 2 common antimicrobial stewardship strategies, syndrome-specific interventions and antimicrobial postprescription prospective audit and feedback (PAF), in reducing AU of APBL at a large community-teaching hospital. METHODS: Four antimicrobial stewardship interventions targeting APBL were serially introduced, including 2 syndrome-specific interventions (bloodstream and intra-abdominal infections) and 2 PAF interventions (carbapenems and piperacillin/tazobactam). Multivariable linear regression was used to examine overall AU of APBL and audited antimicrobial agents. RESULTS: Overall AU of APBL declined from 92.4-69.1 days of therapy (DOT) per 1,000 patient-days between February 2013 and July 2017 (P < .001). Both syndrome-specific interventions were associated with significant reduction in AU of APBL (-7.7 [95% confidence interval (CI): -11.5, -4.0] and -6.0 [95% CI: -9.7, -2.3] DOT per 1,000 patient-days) for bloodstream and intra-abdominal infections, respectively). No significant change in overall AU of APBL was observed after implementation of PAF interventions for carbapenems (-1.4 [95% CI: -7.4, 4.6] DOT per 1,000 patient-days) or piperacillin/tazobactam (0.9 [95% CI: -3.7, 5.4] DOT per 1,000 patient-days). CONCLUSIONS: Implementation of syndrome-specific interventions was followed by significant reduction in AU of APBL in this population. Despite reducing AU of targeted agents, neither PAF intervention contributed to overall observed decline in APBL use, likely due to compensatory increase in using other APBL.