Self-reported beta-lactam allergy and the risk of surgical site infection: A retrospective cohort study

A nurse-driven penicillin allergy risk score in the preoperative setting was associated with increased cefazolin use perioperatively

STUDY OBJECTIVE

To characterize and assess the effects of a preoperative, nurse-driven penicillin allergy risk stratification tool on rates of perioperative cefazolin and second-line antibiotic use.

DESIGN

Quasi-experimental quality improvement study of penicillin-allergic surgical patients undergoing procedures for which cefazolin is indicated.

SETTING

Outpatient Perioperative Care Clinic (PCC) for preoperative surgical patients at a tertiary care center.

PATIENTS

670 and 1371 adult penicillin-allergic PCC attendants and non-attendants, respectively.

INTERVENTION

A paper penicillin allergy risk stratification questionnaire was administered during the PCC visit. Nurses were educated on its use.

MEASUREMENTS

Antibiotic (cefazolin, clindamycin, vancomycin) use rates in the 24 months before and 17 months after intervention implementation in November 2020 (November 2018 - April 2022) were assessed in penicillin-allergic PCC attendants with statistical process control charts. Multivariable logistic regression assessed antibiotic use rates pre- and post-intervention adjusting for age, sex, surgical specialty and penicillin allergy history severity. Similar analyses were done in penicillin-allergic PCC non-attendants.

MAIN RESULTS

Of 670 penicillin-allergic PCC attendants, 451 (median [IQR] age, 66 (Sousa-Pinto et al., 2021 [14])) were analyzed pre-intervention and 219 (median [IQR] age, 66 (Mine et al., 1970 [13])) post-intervention. One month after implementation, process measures demonstrated an upward shift in cefazolin use for PCC attendants versus no shift or other special cause variation for PCC non-attendants. There were increased odds of cefazolin use (aOR 1.67, 95% CI [1.09-2.57], P = 0.019), decreased odds of clindamycin use (aOR 0.61, 95% CI [0.42-0.89], P = 0.010) and decreased odds of vancomycin use (aOR 0.56, 95% CI [0.35-0.88], P = 0.013) in PCC attendants post-intervention. This effect did not occur in PCC non-attendants. There was no increase in perioperative anaphylaxis post-intervention.

CONCLUSIONS

A simple penicillin allergy risk stratification tool implemented in the preoperative setting was associated with increased use of cefazolin and decreased rates of second-line agents post implementation.

Penicillin or cephalosporin antibiotic allergy label: Influence on length of stay and hospital readmission

Background

A penicillin or cephalosporin antibiotic (PCA) allergy label (PCAAL) has negative implications for both the patient and health care alike.

Objective

A retrospective study was undertaken to evaluate the influence of a PCAAL on length of stay (LOS) and hospital readmissions.

Methods

Over 4 weeks, inpatients with a PCAAL who were referred to the allergy service or opportunistically reviewed were grouped in the categories delabeled (group 1a) or advice not followed (ie, label carriage) (group 1b). Comparator groups without a PCAAL were identified, those either on a PCA (the PCA group [group 2]) or on a non-PCA (the non-PCA group [group 3]).

Results

The study population comprised 77 patients as follows: group 1a (n = 19), group 1b (n = 6), group 2 (n = 36), and group 3 (n = 16). Those in group 1a were significantly older (median age 78 years) than those in group 1b (median age 53 years [P = .013]) or group 3 (median age 59 years [P = .013]).There was a trend toward lower LOS in group 1a (10 days) than in group 1b (11.5 days [P = not significant]). Group 2 had a significantly lower LOS (6 days) than either both group 1a (10 days [P = .043]) or group 3 (15 days [P = .002]). Group 3 had the highest rate of patients readmitted within 30 days (n = 5 [71.4%]).

Conclusion

A PCAAL carries influence on both LOS and readmissions, thus identifying the prompt need for allergy review to provide specific recommendations: delabeling and transition to an appropriate antibiotic. The significantly older group of those with a PCAAL who received a PCA after delabeling (ie, a 20-year age difference) may also be a signal that more elderly and comorbid patients benefit from this intervention the most.

[Penicillin allergy-Truth or duty?]

The beta-lactam antibiotics are some of the safest and best-tolerated antibiotic agents; however, many patients have reported allergies against penicillin. All beta-lactam antibiotics are only restrictively prescribed for these patients and alternative antibiotics are increasingly given, which carries the risk of negative clinical results and socioeconomic sequelae; however, over 95% of patients who reported an allergy to penicillin show a negative result in the allergy tests for penicillin and this antibiotic can safely be prescribed. The use of sensitive and specific instruments for identification of false penicillin allergies should be an important topic within the framework of antibiotic stewardship. Anesthesists can play a central role in the reduction of the enormous individual and public health burden associated with the classification of penicillin allergy by taking an appropriate medical history and a risk stratification for the identification of patients with a penicillin allergy. This overview article presents a possible delabelling algorithm within the framework of the clarification of a beta-lactam antibiotic allergy. The focus is on a structured allergy anamnesis using the penicillin allergy, five or fewer years ago, anaphylaxis/angioedema, severe cutaneous adverse reaction (SCAR) and treatment required for allergy episode (PEN-FAST) score.

Optimization of appropriate antimicrobial prophylaxis in general surgery: a prospective cohort study

BACKGROUND

Surgical site infections (SSI) are characterized by infections occurring in the surgical incision site, organ or cavity in the postoperative period. Adherence to surgical antimicrobial prophylaxis (SAP) is paramount in mitigating the occurrence of SSIs. In this study, we aimed to evaluate the appropriateness of SAP use in patients undergoing surgical procedures in the field of general surgery according to the American Society of Health-System Pharmacists (ASHP) guideline and to determine the difference between the pre-training period (pre-TP) and the post-training period (post-TP) organized according to this guideline.

METHODS

It is a single-center prospective study conducted in general surgery wards between January 2022 and May 2023, with 404 patients pre-TP and 406 patients post-TP.

RESULTS

Cefazolin emerged as the predominant agent for SAP, favored in 86.8% (703/810) of cases. Appropriate cefazolin dosage increased significantly from 41% (129 patients) in pre-TP to 92.6% (276 patients) in post-TP (p < 0.001), along with a rise in adherence to recommended timing of administration from 42.2% (133 patients) to 62.8% (187 patients) (p < 0.001). The proportion of patients receiving antibiotics during hospitalization in the ward postoperatively decreased post-TP (21-14.3%; p = 0.012), as did antibiotic prescription at discharge (16.8-10.3%; p = 0.008). The incidence of SSI showed a slight increase from 9.9% in pre-TP to 13.3% in post-TP (p = 0.131).

CONCLUSIONS

Routine training sessions for surgeons emerged as crucial strategies to optimize patient care and enhance SAP compliance rates, particularly given the burden of clinical responsibilities faced by surgical teams.

Impact of penicillin allergy labels on surgical site infections in a large UK cohort of gastrointestinal surgery patients

Objectives

Studies in the USA, Canada and France have reported higher surgical site infection (SSI) risk in patients with a penicillin allergy label (PAL). Here, we investigate the association between PALs and SSI in the UK, a country with distinct epidemiology of infecting pathogens and range of antimicrobial regimens in routine use.

Methods

Electronic health records and national SSI surveillance data were collated for a retrospective cohort of gastrointestinal surgery patients at Cambridge University Hospitals NHS Foundation Trust from 1 January 2015 to 31 December 2021. Univariable and multivariable logistic regression were used to examine the effects of PALs and the use of non-β-lactam-based prophylaxis on likelihood of SSI, 30 day post-operative mortality, 7 day post-operative acute kidney injury and 60 day post-operative infection/colonization with antimicrobial-resistant bacteria or Clostridioides difficile.

Results

Our data comprised 3644 patients and 4085 operations; 461 were undertaken in the presence of PALs (11.3%). SSI was detected after 435/4085 (10.7%) operations. Neither the presence of PALs, nor the use of non-β-lactam-based prophylaxis were found to be associated with SSI: adjusted OR (aOR) 0.90 (95% CI 0.65-1.25) and 1.20 (0.88-1.62), respectively. PALs were independently associated with increased odds of newly identified MRSA infection/colonization in the 60 days after surgery: aOR 2.71 (95% CI 1.13-6.49). Negative association was observed for newly identified infection/colonization with third-generation cephalosporin-resistant Gram-negative bacteria: aOR 0.38 (95% CI 0.16-0.89).

Conclusions

No evidence was found for an association between PALs and the likelihood of SSI in this large UK cohort, suggesting significant international variation in the impact of PALs on surgical patients.

Characterizing Antibiotic Allergy Labels in a Large UK Hospital Population to Inform Antimicrobial Stewardship and Delabeling Assessment Strategy

BACKGROUND

Antibiotic allergy labels are important barriers to treatment and antimicrobial stewardship, but their prevalence in UK hospitals is poorly described.

OBJECTIVE

To ascertain the prevalence and characteristics of antibiotic allergy labels in a large UK hospital setting and estimate the proportion of penicillin allergy labels for which point-of-care (POC) delabeling assessment would be appropriate.

METHODS

Electronic health records data were analyzed from all patients treated at Cambridge University Hospitals NHS Foundation Trust in 2019. Validated POC delabeling risk stratification criteria were retrospectively applied to penicillin allergy labels.

RESULTS

Recorded reactions to antibiotics were present in 11.8% of all patients (32,148 of 273,216), 16.3% of inpatients (13,874 of 85,230), and 9.7% of outpatients (18,274 of 187,986). Penicillins were the commonest reaction precipitant described (9.0% of patients; 24,646 of 273,216), followed by sulfonamides/trimethoprim (1.4%; 3869 of 273,216) and macrolides/lincosamides (1.3%; 3644 of 273,216). A total of 3.9% of inpatients had recorded reactions to >1 antibiotic class (3348 of 85,230). Cutaneous manifestations were the most commonly described reaction features (40.7% of labels; 15,821 of 38,902). Of 15,949 labels describing probable or possible penicillin "allergy" with sufficient detail to allow for the retrospective assessment of POC delabeling suitability, 1702 were deemed suitable for removal or downgrading of the label to "intolerance" without further investigation (10.7%), 11,887 were appropriate for POC assessment using an oral penicillin challenge (OPC) or OPC with prior bedside skin testing (74.5%), and 2360 were identified as unsuitable for any form of POC assessment (14.8%).

CONCLUSIONS

Antibiotic allergy labels are highly prevalent in a UK hospital setting. A large proportion of penicillin allergy labels may be suitable for POC delabeling assessment.

Effect of non-cephalosporin antibiotic prophylaxis on the risk of periprosthetic joint infection after total joint replacement surgery: a retrospective study with a 1-year follow-up

Background

Cephalosporins are recommended as first-line antibiotic prophylaxis in total joint replacement surgery. Studies have shown an increased risk for periprosthetic joint infection (PJI) when non-cephalosporin antibiotics have been used. This study examines the effect of non-cephalosporin antibiotic prophylaxis on the risk for PJI.

Methods

Patients with a primary hip or knee replacement performed from 2012 to 2020 were identified (27 220 joint replacements). The primary outcome was the occurrence of a PJI in a one-year follow-up. The association between perioperative antibiotic prophylaxis and the outcome was examined using logistic regression analysis.

Discussion

Cefuroxime was used as prophylaxis in 26,467 operations (97.2%), clindamycin in 654 (2.4%) and vancomycin in 72 (0.3%). The incidence of PJI was 0.86% (228/26,467) with cefuroxime and 0.80% (6/753) with other prophylactic antibiotics. There was no difference in the risk for PJI with different prophylactic antibiotics in the univariate (OR 1.06, 95% CI 0.47-2.39) or multivariable analysis (OR 1.02, 95% CI 0.45-2.30).

Conclusion

Non-cephalosporin antibiotic prophylaxis in primary total joint replacement surgery was not associated with an increased risk for PJI.

Strategies to prevent surgical site infections in acute-care hospitals: 2022 Update

The intent of this document is to highlight practical recommendations in a concise format designed to assist acute-care hospitals in implementing and prioritizing their surgical-site infection (SSI) prevention efforts. This document updates the Strategies to Prevent Surgical Site Infections in Acute Care Hospitals published in 2014. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA). It is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the Association for Professionals in Infection Control and Epidemiology (APIC), the American Hospital Association (AHA), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise.

Impact of Penicillin Allergy-Based Alternative Antibiotics on the Risk of Postoperative Central Nervous System Infection: A Retrospective Cohort Study

BACKGROUND

Central nervous system (CNS) infection is one of the most serious complications after neurosurgery. This study aimed to analyze the effect of penicillin allergy (PA) and alternative prophylactic antibiotics on risk of postoperative CNS infection in patients undergoing neurosurgery.

METHODS

Data of patients who underwent neurosurgical procedures from January 2015 to December 2021 were analyzed retrospectively. Patients with PA were compared with patients without PA in a 1:1 ratio. A multivariate logistic regression model was used to examine whether PA was a risk factor for postoperative CNS infection.

RESULTS

Overall, 15,049 eligible neurosurgical records were reviewed, from which 578 surgical records of 556 patients with PA were matched to 578 records of 570 patients without PA. Patients with PA showed significantly lower probability to receive prophylactic cephalosporins (55.9% vs. 98.8%, P < 0.01), but significantly higher probability to receive clindamycin (41.86% vs. 1.03%, P < 0.01), than patients without PA. Multivariate analysis revealed that patients with PA were more likely to experience postoperative CNS infection than patients without PA (odds ratio = 2.03; 95% confidence interval, 1.15-3.56; P = 0.014). The incidence of postoperative CNS infection returned to a level comparable to that in general population when patients with suspected PA received prophylactic cephalosporins.

CONCLUSIONS

PA is associated with higher risk of postoperative CNS infection in patients undergoing neurosurgery. This may be attributed to the use of alternative prophylactic antibiotics other than cephalosporins, especially clindamycin.

Self-reported beta-lactam allergy in government and private hospitals in Cape Town, South Africa

BACKGROUND

Up to a quarter of inpatients in high-income countries (HICs) self-report beta-lactam allergy (BLA), which if incorrect,increases the use of alternative antibiotics, worsening individual health outcomes and driving bacterial resistance. In HICs, up to 95% ofself-reported BLAs are incorrect. The epidemiology of BLA in low- and middle-income African countries is unknown.

OBJECTIVES

To describe the epidemiology and de-labelling outcomes of self-reported BLA in hospitalised South African (SA) patients.

METHODS

Point-prevalence surveys were conducted at seven hospitals (adult, paediatric, government and privately funded, district andtertiary level) in Cape Town, SA, between April 2019 and June 2021. Ward prescription records and in-person interviews were conductedto identify and risk-stratify BLA patients using the validated PEN-FAST tool. De-labelling was attempted at the tertiary allergy clinic atGroote Schuur Hospital.

RESULTS

A total of 1 486 hospital inpatients were surveyed (1 166 adults and 320 children). Only 48 patients (3.2%) self-reported a BLA,with a higher rate in private than in government-funded hospitals (6.3% v. 2.8%; p=0.014). Using the PEN-FAST tool, only 10.4% (n=5/48)of self-reported BLA patients were classified as high risk for true penicillin hypersensitivity. Antibiotics were prescribed to 70.8% (n=34/48)of self-reported BLA patients, with 64.7% (n=22/34) receiving a beta-lactam. Despite three attempts to contact patients for de-labelling atthe allergy clinic, only 3/36 underwent in vivo testing, with no positive results, and 1 patient proceeded to a negative oral challenge.

CONCLUSION

Unlike HICs, self-reported BLA is low among inpatients in SA. The majority of those who self-reported BLA were low risk fortype 1 hypersensitivity, but outpatient de-labelling efforts were largely unsuccessful.

Beta-Lactam Allergy Association with Surgical Site Infections in Pediatric Procedures: A Matched Cohort Study

BACKGROUND

Little is known about surgical site infection (SSI) risk among pediatric patients with reported beta-lactam allergy (BLA).

METHODS

We performed a retrospective cohort study at a quaternary children's hospital and compared procedures in patients ages 1-19-years-old with and without BLA that required antimicrobial prophylaxis (AMP) during 2010-2017. Procedures were matched 1:1 by patient age, complex chronic conditions, year of surgery, and National Surgical Quality Improvement Program current procedural terminology category. The primary outcome was SSI as defined by National Healthcare Safety Network. The secondary outcome was AMP protocol compliance as per American Society of Health-System Pharmacists.

RESULTS

Of the 11,878 procedures identified, 1021 (9%) had a reported BLA. There were 35 (1.8%) SSIs in the matched cohort of 1944 procedures with no significant difference in SSI rates in BLA procedures (1.8%) compared to no BLA (1.9%) procedures. Tier 3 AMP was chosen more frequently among BLA procedures (p<0.01). Unmatched analysis of all procedures showed that 23.7% of BLA procedures received beta-lactam-AMP (vs. 93.7% of procedures without BLA). There were no major differences in SSI on sensitivity analysis of BLA procedures that did not receive beta-lactam AMP (1.4%) compared to no BLA procedures with beta-lactam AMP (1.6%) .

CONCLUSIONS

Our retrospective matched analysis of 1944 pediatric procedures found no increase in SSIs in procedures with reported BLA, which differs from studies in adults. We observed that choice of beta-lactam-AMP was common, even in BLA procedures. More data are needed to delineate an association of non-beta-lactam AMP and SSI in children.

Outcomes of Beta-Lactam Allergic and Non-Beta-Lactam Allergic Patients with Intra-Abdominal Infection: A Case-Control Study

Background: In the case of intra-abdominal infections (IAI) in beta-lactam (BL) allergic patients, empiric antimicrobial therapy without BL is recommended; however, data regarding the outcome with alternative regimens are scarce. This study aimed to compare the outcomes of BL allergic (BLA) patients with IAI to those who were non-BLA (NBLA). Method: We conducted a case−control study in a French teaching hospital, between 1 January 2016 and 31 August 2021. BLA patients with IAI treated with fluoroquinolone or aztreonam and metronidazole were matched with controls treated with BL, on age, sex, disease severity, IAI localization, and healthcare-associated infection (HAI) status. We compared rates of therapeutic failures, adverse events, and HAI, and then assessed factors associated with therapeutic failure using a logistic regression model. Results: The therapeutic failure rate was 14% (p > 0.99) in both groups of 43 patients, and there was no significant difference in the adverse events rate (p > 0.99) and HAI rate (p = 0.154). Factors independently associated with therapeutic failure were higher BMI (OR 1.16; 95%CI [1.00−1.36]; p = 0.041), longer hospital length of stay (OR 1,20; 95%CI [1.08−1.41]; p = 0.006), and inadequate empiric antimicrobial therapy (OR 11.71; 95%CI [1.43−132.46]; p = 0.025). Conclusion: The outcomes of BLA patients with IAI treated without BL were the same as those for NBLA patients treated with BL.

National surgical antibiotic prophylaxis guideline in Singapore

Introduction: Institutional surgical antibiotic prophylaxis (SAP) guidelines are in place at all public hospitals in Singapore, but variations exist and adherence to guidelines is not tracked consistently. A national point prevalence survey carried out in 2020 showed that about 60% of surgical prophylactic antibiotics were administered for more than 24 hours. This guideline aims to align best practices nationally and provides a framework for audit and surveillance. Method: This guideline was developed by the National Antimicrobial Stewardship Expert Panel’s National Surgical Antibiotic Prophylaxis Guideline Development Workgroup Panel, which comprises infectious diseases physicians, pharmacists, surgeons and anaesthesiologists. The Workgroup adopted the ADAPTE methodology framework with modifications for the development of the guideline. The recommended duration of antibiotic prophylaxis was graded according to the strength of consolidated evidence based on the scoring system of the Singapore Ministry of Health Clinical Practice Guidelines. Results: This National SAP Guideline provides evidence-based recommendations for the rational use of antibiotic prophylaxis. These include recommended agents, dose, timing and duration for patients undergoing common surgeries based on surgical disciplines. The Workgroup also provides antibiotic recommendations for special patient population groups (such as patients with β-lactam allergy and patients colonised with methicillin-resistant Staphylococcus aureus), as well as for monitoring and surveillance of SAP. Conclusion: This evidence-based National SAP Guideline for hospitals in Singapore aims to align practices and optimise the use of antibiotics for surgical prophylaxis for the prevention of surgical site infections while reducing adverse events from prolonged durations of SAP. Keywords: Antibiotic prophylaxis duration, antimicrobial resistance, antimicrobial stewardship, hospital-acquired infection, surgical site infections

Beta-lactam allergies, surgical site infections, and prophylaxis in solid organ transplant recipients at a single center: A retrospective cohort study

BACKGROUND

Beta-lactam allergies (BLAs) are common in hospitalized patients, including transplant recipients. BLA is associated with decreased use of preferred surgical site infection (SSI) prophylaxis and increased SSIs, but this has not been studied in the transplant population.

METHODS

We reviewed adult heart, kidney, and liver transplant recipients between January 1, 2016 and December 31, 2019 to characterize reported BLA and collect SSI prophylaxis regimens at time of transplant. We compared the use of preferred SSI prophylaxis and SSI incidence based on reported BLA status. Post hoc we collected antibiotic days of therapy (DOT) (excluding pneumocystis prophylaxis) in the 30-day period posttransplant for patients without SSI. We utilized descriptive statistics for comparisons.

RESULTS

Of 691 patients included (116 heart, 400 kidney, and 175 liver transplant recipients), 118 (17%) reported BLA. Rash and hives were the two most reported BLA reactions (36% and 24%), categorized as potential T-cell mediated and IgE mediated, respectively. Preferred SSI prophylaxis was prescribed in 13 (11%) patients with BLA and 573 (92%) without BLA (p < .001). No difference could be detected in SSI incidence between BLA and non-BLA patients (4.2 vs. 4.3%, p = 1.0). Of 659 without SSI, 169 (25.6%) received antibiotics within 30 days of transplant; mean antibiotic DOT for BLA and non-BLA patients were 3.5 ± 8.0 versus 2.3 ± 5.8, p = .12.

CONCLUSION

BLA transplant recipients received nonpreferred SSI prophylaxis more frequently than non-BLA recipients, but there was no difference in 30-day SSIs between the groups. One-fourth of solid organ transplant recipients received systemic antibiotics within 30 days of transplant.

A work in progress: antimicrobial stewardship in solid organ transplant patient populations

PURPOSE OF REVIEW

To review recent medical literature addressing antimicrobial stewardship in solid organ transplant (SOT) recipients.

RECENT FINDINGS

Few studies with a strict focus on SOT patients have been published to date. Team-based antimicrobial stewardship interventions in SOT populations do have beneficial impacts on antimicrobial stewardship-relevant outcomes. Several studies have compared SOT-specific antibiograms to widely accepted hospital antibiograms; these studies all have found important differences in resistance rates among bacterial pathogens. Novel biomarkers like virome monitoring for assessing the net state of immunosuppression hold promise for individualized antimicrobial stewardship interventions.

SUMMARY

SOT patients are an understudied population with respect to antimicrobial stewardship interventions. Current antimicrobial stewardship interventions for SOT patients are largely extrapolated from studies in general patient populations and may not accurately reflect SOT-specific infection risks or outcomes. Antimicrobial stewardship interventions do impact SOT-relevant care goals but require significantly more research to achieve the depth and reach of antimicrobial stewardship interventions developed for general populations.

Clindamycin use in head and neck surgery elevates the rate of infections in tracheostomies

Background

Surgical site infection (SSI) in open surgical tracheostomy (ST) occurs in up to 33% of the cases. SSI can be reduced by a postoperative antibiotic prophylaxis (POAP). The effect of Clindamycin on SSIs in head and neck surgery (HNS) is discussed controversially in the literature.

Methods

An 8 year single-center retrospective comparative analysis of 441 STs (Visor-ST and Bjoerk-flap technique) performed within major HNS was evaluated due to the event of a SSI within 7 days and analyzed descriptively. Logistic regression model evaluated the impact of POAP with Clindamycin on SSIs.

Results

The use of Clindamycin showed twice the rate of ST-SSI as all patients that did not receive Clindamycin, treated with other perioperative antibiotics. (Fisher’s p = 0.008) The logistic regression model could not prove a statistically significant impact. (OR = 2.91, p = 0.04).

Conclusion

We recommend that Clindamycin should be reconsidered as a POAP regimen in ST. Further studies should evaluate alternatives for Penicillin-allergic patients.

Level of evidence III

Comparative retrospective monocentric study.

Documented β-Lactam Allergy and Risk for Cesarean Surgical Site Infection

Objective

To examine the relationship between documented β-lactam allergy and cesarean delivery (CD) surgical site infection (SSI). Study Design. We conducted a retrospective cohort analysis of women who underwent CD at Ben Taub Hospital and Texas Children's Pavilion for Women (Houston, TX) from August 1, 2011, to December 31, 2019. The primary exposure was a documented β-lactam allergy, and the second exposure of interest was the type of perioperative antibiotic received. The primary outcome was the prevalence of SSI. Maternal characteristics were stratified by the presence or absence of a documented β-lactam allergy, and significance was evaluated using Pearson's chi-squared test for categorical variables and t-test for continuous variables. A logistic regression model estimated odds of SSI after adjusting for possible confounders.

Results

Of the 12,954 women included, 929 (7.2%) had a documented β-lactam allergy while 12,025 (92.8%) did not. Among the 929 women with a β-lactam allergy, 495 (53.3%) received non-β-lactam perioperative prophylaxis. SSI occurred in 38 (4.1%) of women who had a β-lactam allergy versus 238 (2.0%) who did not (p ≤ 0.001). β-Lactam allergy was associated with higher odds of SSI compared to no allergy (adjusted odds ratio (aOR) = 1.97; 95%confidence interval (CI) = 1.24-3.14; p = 0.004) after controlling for age, race, ethnicity, insurance status, delivery body mass index (BMI), tobacco use, intra-amniotic infection in labor, duration of membrane rupture, preterm delivery, delivery indication, diabetes, hypertension, group B Streptococcus colonization, and type of perioperative antibiotic received.

Conclusion

The presence of a β-lactam allergy is associated with increased odds of developing a CD SSI after controlling for possible confounders, including the type of perioperative antibiotic received.

Immediate and Delayed Hypersensitivity Reactions to Beta-Lactam Antibiotics

Beta-lactam antibiotics are the most commonly reported drug allergy in adults and children. More than 95% of those with reported allergy labels to beta lactams are not confirmed when subjected to allergy testing. Beta lactam antibiotics are associated with a wide spectrum of immediate and delayed drug hypersensitivity reactions. The latency period to symptoms and clinical presentation aids in the causality assessment. Risk stratification based on diagnosis and timing then allows for appropriate management and evaluation. Skin prick testing, intradermal testing and oral challenge are well established for evaluation of immediate reactions. Delayed intradermal testing, patch testing and oral challenge can also be considered for evaluation of mild to moderate delayed reactions. Cross-reactivity between beta-lactams appears to be driven most commonly by a shared R1 side-chain. Standardized algorithms, protocols and pathways are needed for widespread implementation of a pragmatic and effective approach to patients reporting beta lactam allergy.

Is Penicillin Allergy a Risk Factor for Surgical Site Infection After Oral and Maxillofacial Surgery?

PURPOSE

The selection of perioperative antibiotics for prevention of surgical site infection (SSI) is often limited by the presence of a reported penicillin allergy. The purpose of this study was to determine if oral and maxillofacial surgery patients who report allergy to penicillin are at an increased risk of developing SSI.

METHODS

A retrospective cohort study was performed of patients who underwent oral and maxillofacial surgical procedures in the operating room setting at a single institution between 2011 and 2018. The following categories of procedures were investigated: dentoalveolar, orthognathic, orthognathic with third molar extraction, pathology and reconstruction, and temporomandibular joint. The primary predictor and outcome variables were reported penicillin allergy and surgical site infection, respectively. Bivariate and multiple logistic regression analysis were performed. P < .05 was considered to be significant.

RESULTS

The cohort was composed of 2,058 patients of which 318 (15.5%) reported allergy to penicillin. Beta-lactam antibiotics were administered less frequently to penicillin allergic patients perioperatively compared with those without penicillin allergy (7.9 vs 97.1%, P < .001), while clindamycin was more commonly administered (76.4 vs 2.5%, P < .001). Clindamycin was associated with a higher SSI rate compared with beta-lactam antibiotics (5.6 vs 1.4%, P < .001). Penicillin allergy was significantly associated with SSI at an adjusted odds ratio of 2.61 (95% CI 1.51 to 4.49, P = .001). After holding perioperative antibiotic usage equal between the 2 groups, penicillin allergy per se was no longer associated with SSI (P = .901), suggesting that the outcome was mediated by antibiotic selection.

CONCLUSIONS

Penicillin allergy was associated with development of SSI due to receipt of non-beta-lactam antibiotics as perioperative prophylaxis. Formal allergy evaluation should be considered for patients with putative penicillin allergy.

Comparison of immediate hypersensitivity reactions to preoperative antibiotics in patients labeled as penicillin allergic

BACKGROUND

Cefazolin is routinely recommended as the first-line agent for surgical antibiotic prophylaxis because it prevents more surgical site infections than second-line antibiotics. Clinicians often avoid administering cefazolin to patients who are labeled as penicillin allergic due to concerns of cross-reactivity. The aim of this study was to compare the incidence of hypersensitivity reactions between cefazolin and the second-line antibiotics vancomycin and clindamycin.

METHODS

This retrospective study included patients who were labeled as penicillin allergic and received either cefazolin, clindamycin, or vancomycin as preoperative antibiotics. The primary outcome was intraoperative hypersensitivity reactions.

RESULTS

A total of 734 surgical procedures in 690 patients were included. Fifteen immediate hypersensitivity reactions were identified. Probable hypersensitivity reactions occurred in 3 (0.9%) patients in the cefazolin group, 4 (1.4%) in the clindamycin group, and 1 (1.1%) in the vancomycin group. Seven of 8 patients reported allergies to additional medications beyond penicillin. There were seven cases of possible hypersensitivity reactions, 3 (0.9%) in the cefazolin group, 1 (1.1%) in the vancomycin group, and 3 (1.0%) in the clindamycin group.

CONCLUSION

Our data suggest that perioperative hypersensitivity reactions are uncommon in patients labeled as penicillin allergic. The frequency of immediate hypersensitivity reactions was not different between patients receiving cefazolin, clindamycin, or vancomycin. Avoiding cefazolin in patients labeled as penicillin allergic may not be warranted.

Investigating the impact of a β-lactam allergy label on preoperative antibiotic prophylaxis administration

OBJECTIVE

Surgical site infection (SSI) is a common postprocedure complication that may be prevented by adhering to established recommendations, including administration of preoperative antibiotic prophylaxis. Patients with a β-lactam allergy (BLA) label have an increased risk of SSI. We sought to evaluate the appropriateness of preoperative antibiotic prophylaxis in patients labeled with a BLA compared those without a BLA.

METHODS

This was a single-center, retrospective, matched cohort study of adult patients who underwent a clean or clean-contaminated knee replacement, abdominal hysterectomy, colorectal surgery, or coronary artery bypass graft (CABG). Patients with a BLA label were matched to patients without a BLA label based on procedure, age, and body mass index (BMI). The primary end point was the rate of appropriate preoperative antibiotic prophylaxis, including antibiotic selection and timing prior to incision.

RESULTS

In total, 260 patients were included. Knee replacement (38%) was the most common procedure, followed by abdominal hysterectomy (25%), colorectal surgery (18%), and CABG (18%). Appropriate preoperative antibiotic prophylaxis was higher among patients without a BLA (76% vs 37%; P < .001). Among patients with a mild-to-moderate reaction or intolerance, 29 (53%) received antibiotics that would have been appropriate only if the patient had had a severe BLA. Patients with a BLA were more likely to have had an antibiotic omitted from the prophylactic regimen (44% vs 4%; P < .001).

CONCLUSION

Patients with a BLA were more likely to receive inappropriate preoperative antibiotic prophylaxis, attributed to misinterpretation of BLA labels and antibiotic omissions. Optimizing antibiotic prophylaxis among patients with BLAs remains an area of opportunity to prevent SSIs.

Preoperative penicillin allergy testing in patients undergoing cardiac surgery

BACKGROUND

Cefazolin is a first-line prophylactic antibiotic used to prevent surgical site infections (SSIs) in cardiac surgery. Patients with a history of penicillin allergy often receive less effective second-line antibiotics, which is associated with an increased SSI risk.

OBJECTIVE

To describe the impact of preoperative penicillin allergy evaluation on perioperative cefazolin use in patients undergoing cardiac surgery.

METHODS

We performed a retrospective cohort study of patients with a documented penicillin allergy who underwent cardiac surgery at the Massachusetts General Hospital from September 2015 to December 2018. We describe penicillin allergy evaluation assessment and outcomes. We evaluated the association between preoperative penicillin allergy evaluation and first-line perioperative antibiotic use using a multivariable logistic regression model.

RESULTS

Of 3802 cardiac surgical patients, 510 (13%) had a documented penicillin allergy; 165 (33%) were referred to allergy and immunology practitioners. Of 160 patients (31%) who underwent penicillin allergy evaluation (ie, penicillin skin testing and, if results were negative, an amoxicillin challenge), 154 (97%) were found not to have a penicillin allergy. Patients who underwent preoperative penicillin allergy evaluation were more likely to receive the first-line perioperative antibiotic (92% vs 38%, P < .001). After adjusting for potential confounders, patients who underwent preoperative penicillin allergy evaluation had higher odds of first-line perioperative antibiotic use (adjusted odds ratio, 26.6; 95% CI, 12.8-55.2).

CONCLUSION

Integrating penicillin allergy evaluation into routine preoperative care ensured that almost all evaluated patients undergoing cardiac surgery received first-line antibiotic prophylaxis, a critical component of SSI risk reduction. Further efforts are needed to increase access to preoperative allergy evaluation.