Original Research
Monday, October 14, 2024
01:00 PM–02:30 PM
Abstract
Introduction:
Around 10% of the population reports a penicillin allergy. Most are not truly allergic, yet little research exists on how penicillin allergies affect antibiograms, particularly gram-negative organisms that contribute to Urinary Tract Infections (UTI).
Research Question or Hypothesis:
Do documented penicillin allergies adversely affect gram-negative susceptibilities on an antibiogram?
Study Design:
Retrospective, observational chart review
Methods:
Patients admitted in 2022 to a two-hospital community health system with a first positive bacterial culture for common UTI gram-negative organisms were separated into non-penicillin-allergic and penicillin-allergic cohorts. Descriptive statistics were collected, including type (allergy, adverse reaction, or unknown), severity (mild, intermediate, severe, or unknown), and reported reaction (e.g., rash, shortness of breath). Two-sided, independent sample t-tests were used to compare susceptibility rates between cohorts. The primary objective was to determine if a documented penicillin allergy affected susceptibility to common UTI organisms.
Results:
Penicillin allergy was documented in 484/3757 patients (12.8%). The allergy cohort had significantly lower susceptibilities for the following gram-negative organisms compared to the non-allergic cohort: Escherichia coli and Proteus mirabilis (Table 1). Twelve percent of allergy types were adverse reactions, not true allergies. Unknown severity (63%) was the most reported, with severe reactions occurring in only 15% of patients. Reported reactions varied significantly, with unknown (35%) and rash (19%) predominating.
Conclusion:
Self-reported penicillin allergies were frequently unknown in both severity and reported reaction and associated with significant decreases in certain gram-negative organism susceptibility. Future studies should evaluate long-term impacts of de-labeling on antibiograms.
Table 1
|
|
E. coli
|
P. mirabilis
|
|
Susceptibility (%)
|
Penicillin allergic
|
Non-penicillin allergic
|
p-value
|
Penicillin allergic
|
Non-penicillin allergic
|
p-value
|
|
Levofloxacin
|
59
|
76
|
<0.001
|
66
|
83
|
0.025
|
|
Ciprofloxacin
|
59
|
75
|
<0.001
|
66
|
83
|
0.025
|
|
TMP/SMX
|
68
|
78
|
0.002
|
72
|
84
|
0.012
|
|
Cefepime
|
94
|
96
|
>0.05
|
90
|
98
|
0.0015
|
|
Gentamicin
|
90
|
91
|
>0.05
|
75
|
92
|
0.006
|
|
Piperacillin/tazobactam
|
94
|
96
|
>0.05
|
94
|
99
|
0.012
|
Presenting Author
Katherine Weller Pharm.D. CandidateUniversity of Georgia College of Pharmacy
Authors
Christopher M. Bland Pharm.D., FCCP, FIDSA, BCPS
University of Georgia College of Pharmacy
Logan Bradley Pharm.D.
St. Joseph's Candler Health System, Inc.
Bruce M. Jones Pharm.D., FIDSA, BCPS
St. Joseph's/Candler Health System
Susan E. Smith PharmD, BCCCP, FCCM
University of Georgia College of Pharmacy