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A Single-Center Evaluation of Extended Infusion Piperacillin/Tazobactam for Empiric Treatment in the Intensive Care
Kendall Tucker1, Molly Benning2, Keenan Ryan2
1Oregon State University/Oregon Health & Science University, Portland, OR, USA.
Abstract:
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.
Insights
Piperacillin/tazobactam extended infusion may not adequately treat Gram-negative infections in ICUs. Factors like dialysis and prior antibiotic use are linked to resistance, suggesting current dosing needs review for optimal patient care.
Area of Science:
- Infectious Diseases
- Critical Care Medicine
- Pharmacology
Background:
- Piperacillin/tazobactam extended infusion (PTZ EI) is a common empirical treatment in intensive care units (ICUs).
- Gram-negative (GN) organisms with high piperacillin/tazobactam minimum inhibitory concentrations (MICs) indicate potential resistance.
- Assessing PTZ EI appropriateness is crucial for effective empirical antimicrobial therapy in critically ill patients.
Purpose of the Study:
- To evaluate the minimum inhibitory concentrations (MICs) of Gram-negative (GN) isolates from ICU patients.
- To determine if the hospital's protocol for piperacillin/tazobactam (PTZ) 3.375 g extended infusion (EI) over 4 hours every 8 hours is appropriate for empirical use.
- To identify patient-specific risk factors associated with elevated PTZ MICs in the ICU setting.
Main Methods:
- Retrospective chart review of ICU patients admitted in 2017 with confirmed GN organisms from non-urinary sources.
- Exclusion criteria included cystic fibrosis or cultures obtained more than 48 hours before ICU admission.
- Data collected: demographics, GN organism, culture source, risk factors for resistance, susceptibility profiles, comorbidities, and creatinine clearance.
Main Results:
- 231 patients were included; the most common organism was *Pseudomonas aeruginosa* (41%).
- 28% of Gram-negative isolates exhibited piperacillin/tazobactam MICs >16/4 µg/mL, exceeding the susceptibility threshold.
- Risk factors associated with elevated MICs included dialysis (P=.01), recent intravenous antibiotic use (P<.001), and wounds/trauma (P=.01).
Conclusions:
- Current piperacillin/tazobactam extended infusion (3.375 g) dosing may not ensure adequate empirical coverage for all Gram-negative organisms in ICU patients.
- Patients on dialysis, with a history of recent intravenous antibiotic exposure, or with wounds/trauma are at higher risk for infections with less susceptible organisms.
- Re-evaluation of empirical PTZ EI regimens in ICUs is warranted to optimize treatment outcomes and combat antimicrobial resistance.
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