A prospective observational study of the effect of penicillin skin testing on antibiotic use in the intensive care unit

Penicillin Allergy Impact and Management

There is international evidence that penicillin allergies are associated with inferior prescribing and patient outcomes. A host of tools now exist from assessment (risk assessment tools, clinical decision rules) to delabeling (the removal of a beta-lactam allergy via testing or medical reconciliation) to reduce the impact of these "labels" in the hospital and community setting, as a primary antimicrobial stewardship intervention.

Meropenem allergy testing performed at the bedside of hospitalized patients labelled with a penicillin allergy

BACKGROUND

Meropenem is a widely prescribed beta-lactam for hospitalized patients. There are few data on meropenem allergy assessments in inpatients with a reported history of penicillin allergy who require a treatment with meropenem. This can lead to the use of less effective second-line antibiotics that may increase antibiotic resistances. We aimed to evaluate the clinical outcomes of a meropenem allergy assessment in admitted patients with a reported history of penicillin allergy that required meropenem for the treatment of an acute infection.

METHODS

A retrospective analysis was performed on 182 inpatients labelled with a penicillin-allergy who received meropenem after an allergy assessment. The allergy study was performed bedside if meropenem was required urgently. The study included skin prick tests (SPTs) followed by an intradermal skin test (IDT) to meropenem, and a meropenem drug challenge test (DCT). If a non-immediate reaction to a beta-lactam was suspected, it was initiated with patch tests.

RESULTS

The median age of the patients was 59.7 years (range 28-95) and 80 (44%) were women. A total of 196 sets of diagnostic workups were performed, with 189 (96.4%) of them being tolerated. Only two patients had a positive meropenem IV DCT, both presenting a non-severe cutaneous reaction that completely resolved after treatment.

CONCLUSIONS

This study evidenced that a bedside meropenem allergy assessment of hospitalized patients labelled with a 'penicillin allergy' who require a broad-spectrum antibiotic for empiric coverage is a safe and effective procedure, avoiding the use of second-line antimicrobial agents.

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.

The impact of patient-reported penicillin or cephalosporin allergy on surgical site infections

OBJECTIVE

To determine the impact of a documented penicillin or cephalosporin allergy on the development of surgical site infections (SSIs).

BACKGROUND

Appropriate preoperative antibiotic prophylaxis reduces SSI risk, but documented antibiotic allergies influence the choice of prophylactic agents. Few studies have examined the relationship between a reported antibiotic allergy and risk of SSI and to what extent this relationship is modified by the antibiotic class given for prophylaxis.

METHODS

We conducted a retrospective cohort study of adult patients undergoing coronary artery bypass, craniotomy, spinal fusion, laminectomy, hip arthroplasty and knee arthroplasty at 3 hospitals from July 1, 2013, to December 31, 2017. We built a multivariable logistic regression model to calculate the adjusted odds ratio (aOR) of developing an SSI among patients with and without patient-reported penicillin or cephalosporin allergies. We also examined effect measure modification (EMM) to determine whether surgical prophylaxis affected the association between reported allergy and SSI.

RESULTS

We analyzed 39,972 procedures; 1,689 (4.2%) with a documented patient penicillin or cephalosporin allergy, and 374 (0.9%) resulted in an SSI. Patients with a reported penicillin or cephalosporin allergy were more likely to develop an SSI compared to patients who did not report an allergy to penicillin or cephalosporins (adjusted odds ratio, 3.26; 95% confidence interval, 2.71-3.93). Surgical prophylaxis did not have significant EMM on this association.

CONCLUSIONS

Patients who reported a penicillin or cephalosporin allergy had higher odds of developing an SSI than nonallergic patients. However, the increase in odds is not completely mediated by the type of surgical prophylaxis. Instead, a reported allergy may be a surrogate marker for a more complicated patient population.

Antibiotic Skin Testing in the Intensive Care Unit: A Systematic Review

BACKGROUND

Recent research has shown that a large majority of patients with a history of penicillin allergy are acutely tolerant of penicillins and that there is no clinically significant immunologic cross-reactivity between penicillins and cephalosporins or other β-lactams. The standard test to confirm acute tolerance is challenge with a therapeutic dose. Skin testing is useful only when the culprit antibiotic can haptenate serum proteins and induce an immunoglobulin E-mediated reaction and the clinical history demonstrates such high risk that a direct oral challenge may result in anaphylaxis.

OBJECTIVE

To review and evaluate the current practice of skin testing for antibiotics (other than penicillin) in critically ill patients by means of a systematic literature review.

METHODS

This systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. Several electronic databases were searched using the following terms: antibiotics, skin test (tests, testing), intensive care, intensive care unit, ICU, critical care, critical care unit.

RESULTS

Twenty-three articles were identified for inclusion in this review. The results indicate a lack of standardized skin testing for all antibiotics in critical care settings. Oral challenge with nonirritating concentrations of antibiotics can be helpful in determining allergy to these drugs.

CONCLUSIONS

Critical care providers should evaluate antibiotic allergy using nonirritating concentrations before administering antibiotics to patients. Introduction of a standardized skin test for all antibiotics in intensive care unit patients to help select the most appropriate antibiotic treatment regimen might help save lives and reduce costs.

The Impact of a Reported Penicillin Allergy on Surgical Site Infection Risk

Background

A reported penicillin allergy may compromise receipt of recommended antibiotic prophylaxis intended to prevent surgical site infections (SSIs). Most patients with a reported penicillin allergy are not allergic. We determined the impact of a reported penicillin allergy on the development of SSIs.

Methods

In this retrospective cohort study of Massachusetts General Hospital hip arthroplasty, knee arthroplasty, hysterectomy, colon surgery, and coronary artery bypass grafting patients from 2010 to 2014, we compared patients with and without a reported penicillin allergy. The primary outcome was an SSI, as defined by the Centers for Disease Control and Prevention's National Healthcare Safety Network. The secondary outcome was perioperative antibiotic use.

Results

Of 8385 patients who underwent 9004 procedures, 922 (11%) reported a penicillin allergy, and 241 (2.7%) had an SSI. In multivariable logistic regression, patients reporting a penicillin allergy had increased odds (adjusted odds ratio, 1.51; 95% confidence interval, 1.02-2.22) of SSI. Penicillin allergy reporters were administered less cefazolin (12% vs 92%; P < .001) and more clindamycin (49% vs 3%; P < .001), vancomycin (35% vs 3%; P < .001), and gentamicin (24% vs 3%; P < .001) compared with those without a reported penicillin allergy. The increased SSI risk was entirely mediated by the patients' receipt of an alternative perioperative antibiotic; between 112 and 124 patients with reported penicillin allergy would need allergy evaluation to prevent 1 SSI.

Conclusions

Patients with a reported penicillin allergy had a 50% increased odds of SSI, attributable to the receipt of second-line perioperative antibiotics. Clarification of penicillin allergies as part of routine preoperative care may decrease SSI risk.

Point-of-Care β-Lactam Allergy Skin Testing by Antimicrobial Stewardship Programs: A Pragmatic Multicenter Prospective Evaluation

Background

β-lactam allergy skin testing (BLAST) is recommended by antimicrobial stewardship program (ASP) guidelines, yet few studies have systematically evaluated its impact when delivered at point of care.

Methods

We conducted a pragmatic multicenter prospective evaluation of the use of point-of-care BLAST by ASPs. In staggered 3-month intervals, ASP teams at 3 hospitals received training by allergists to offer BLAST for eligible patients with infectious diseases receiving nonpreferred therapy due to severity of their reported allergy. The primary outcome was the proportion of patients receiving the preferred β-lactam therapy.

Results

Of 827 patients with reported β-lactam allergy over 15 months, β-lactam therapy was preferred among 632 (76%). During baseline periods, 50% (124/246) received preferred β-lactam therapy based on history, compared with 60% (232/386) during the intervention periods (P = .02), which improved further to 81% (313/386) upon provision of BLAST (P < .001) without any increase in incidence of adverse drug reactions (4% vs 3%; P = .4). After adjusting for patient variables and the correlation between hospitals, the intervention period was associated with a 4.5-fold greater odds of receiving preferred β-lactam therapy (95% confidence interval, 2.4-8.2; P < .0001).

Conclusions

The use of BLAST at the point of care across 3 hospital ASPs resulted in greater use of preferred β-lactam therapy without increasing the risk of adverse drug reactions. Longer-term studies are needed to better assess the safety and clinical impact of this ASP intervention.

Management of a surgical patient with a label of penicillin allergy: narrative review and consensus recommendations

Unsubstantiated penicillin-allergy labels are common in surgical patients, and can lead to significant harm through avoidance of best first-line prophylaxis of surgical site infections and increased infection with resistant bacterial strains. Up to 98% of penicillin-allergy labels are incorrect when tested. Because of the scarcity of trained allergists in all healthcare systems, only a minority of surgical patients have the opportunity to undergo testing and de-labelling before surgery. Testing pathways can be modified and shortened in selected patients. A variety of healthcare professionals can, with appropriate training and in collaboration with allergists, provide testing for selected patients. We review how patients might be assessed, the appropriate testing strategies that can be used, and the minimum standards of safe testing.

Antibiotic allergy labels in hospitalized and critically ill adults: A review of current impacts of inaccurate labelling

Antibiotic allergy labels (AALs) are reported by approximately 20% of hospitalized patients, yet over 85% will be negative on formal allergy testing. Hospitalized patients with an AAL have inferior patient outcomes, increased colonization with multidrug-resistant organisms and frequently receive inappropriate antimicrobials. Hospitalized populations have been well studied but, to date, the impact of AALs on patients with critical illness remains less well defined. We review the prevalence and impact of AALs on hospitalized patients, including those in in critical care.

Patient and Prescriber Views of Penicillin Allergy Testing and Subsequent Antibiotic Use: A Rapid Review

About 10% of U.K. patients believe that they are allergic to penicillin and have a "penicillin allergy label" in their primary care health record. However, around 90% of these patients may be mislabelled. Removing incorrect penicillin allergy labels can help to reduce unnecessary broad-spectrum antibiotic use. A rapid review was undertaken of papers exploring patient and/or clinician views and experiences of penicillin allergy testing (PAT) services and the influences on antibiotic prescribing behaviour in the context of penicillin allergy. We reviewed English-language publications published up to November 2017. Limited evidence on patients' experiences of PAT highlighted advantages to testing as well as a number of concerns. Clinicians reported uncertainty about referral criteria for PAT. Following PAT and a negative result, a number of clinicians and patients remained reluctant to prescribe and consume penicillins. This appeared to reflect a lack of confidence in the test result and fear of subsequent reactions to penicillins. The findings suggest lack of awareness and knowledge of PAT services by both clinicians and patients. In order to ensure correct penicillin allergy diagnosis, clinicians and patients need to be supported to use PAT services and equipped with the skills to use penicillins appropriately following a negative allergy test result.

Improving Aztreonam Stewardship and Cost Through a Penicillin Allergy Testing Clinical Guideline

Background

Patients reporting penicillin allergy often receive unnecessary and costly broad-spectrum alternatives such as aztreonam with negative consequences. Penicillin allergy testing improves antimicrobial therapy but is not broadly used in hospitals due to insufficient testing resources and short-term expenses. We describe a clinical decision support (CDS) tool promoting pharmacist-administered penicillin allergy testing in patients receiving aztreonam and its benefits toward antimicrobial stewardship and costs.

Methods

A CDS tool was incorporated into the electronic medical record, directing providers to order penicillin allergy testing for patients receiving aztreonam. An allergy-trained pharmacist reviewed orders placed through this new guideline and performed skin testing and oral challenges to determine whether these patients could safely take penicillin. Data on tests performed, antibiotic utilization, and cost-savings were compared with patients tested outside the new guideline as part of our institution's standard stewardship program.

Results

The guideline significantly increased penicillin allergy testing among patients receiving aztreonam from 24% to 85% (P < .001) while reducing the median delay between admission and testing completion from 3.31 to 1.05 days (P = 0.008). Patients tested under the guideline saw a 58% increase in penicillin exposure (P = .046). Institutional aztreonam administration declined from 2.54 to 1.47 administrations per 1000 patient-days (P = .016). Average antibiotic costs per patient tested before and after CDS decreased from $1265.81 to $592.08 USD, a 53% savings.

Conclusions

Targeting penicillin allergy testing to patients on aztreonam yields therapeutic and economic benefits during a single admission. This provides a cost-effective model for inpatient testing.

Addressing Inpatient Beta-Lactam Allergies: A Multihospital Implementation

Addressing inaccurate penicillin allergies is encouraged as part of antibiotic stewardship in the inpatient setting. However, implementing interventions targeted at the 10% to 15% of inpatients reporting a previous penicillin allergy can pose substantial logistic challenges. We implemented a computerized guideline for patients with reported beta-lactam allergy at 5 hospitals within a single health care system in the Boston area. In this article, we describe our implementation roadmap, including both successes achieved and challenges faced. We explain key implementation steps, including assembling a team, stakeholder engagement, developing or selecting an approach, spreading the change, establishing measures, and measuring impact. The objective was to detail the lessons learned while empowering others to be part of this important, multidisciplinary work to improve the care of patients with reported beta-lactam allergies.

Influence of Reported Penicillin Allergy on Mortality in MSSA Bacteremia

Background

Penicillin allergy frequently impacts antibiotic choice. As beta-lactams are superior to vancomycin in treating methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia, we examined the effect of reported penicillin allergy on clinical outcomes in patients with MSSA bacteremia.

Methods

In this retrospective cohort study of adults with MSSA bacteremia admitted to a large tertiary care hospital, outcomes were examined according to reported penicillin allergy. Primary outcomes included 30-day and 90-day mortality rates. Multivariable regression models were developed to quantify the effect of reported penicillin allergy on mortality while adjusting for potential confounders.

Results

From 2010 to 2015, 318 patients with MSSA bacteremia were identified. Reported penicillin allergy had no significant effect on adjusted 30-day mortality (odds ratio [OR], 0.73; 95% confidence interval [CI], 0.29-1.84; P = .51). Patients with reported penicillin allergy were more likely to receive vancomycin (38% vs 11%, P < .01), but a large number received cefazolin regardless of reported allergy (29 of 66, 44%). Mortality rates were highest among nonallergic patients receiving vancomycin (22.6% vs 7.4% for those receiving beta-lactams regardless of reported allergy, P < .01). In multivariable analysis, beta-lactam receipt was most strongly associated with survival (OR, 0.26; 95% CI, 0.12-0.54).

Conclusions

Reported penicillin allergy had no significant effect on 30- or 90-day mortality. Non-penicillin-allergic patients receiving vancomycin for treatment of MSSA bacteremia had the highest mortality rates overall. Receipt of a beta-lactam was the strongest predictor of survival. These results underscore the importance of correct classification of patients with penicillin allergy and appropriate treatment with a beta-lactam when tolerated.

The Cost of Self-Reported Penicillin Allergy: A Systematic Review

BACKGROUND

Patients who report a penicillin (PCN) allergy receive suboptimal antibiotic therapy compared with patients not reporting an allergy. However, a majority of patients who report PCN allergy are not truly allergic on confirmatory testing. Ruling out PCN allergy by testing may improve clinical and economic outcomes for patients with reported allergies requiring antibiotic therapy.

OBJECTIVE

The objective of this study was to summarize clinical and economic outcomes associated with PCN allergy and provide recommendations for future cost-effectiveness analyses for PCN allergy testing.

METHODS

A literature search was conducted using SCOPUS, EMBASE, and PubMed, including all articles published any date through April 25, 2017 (PROSPERO Registration number 42017064112). A total of 1518 abstracts were found during the initial search with 96 duplicates, for a total of 1422 articles for screening. Thirty articles were included for qualitative synthesis and full data extraction.

RESULTS

The majority of the studies included had an observational design focusing on inpatient admissions. The most frequently measured outcome in the context of PCN allergy was optimizing antibiotic therapy. Patients with PCN allergy were found to have direct drug costs during inpatient admission ranging from no difference to an additional $609/patient compared with patients without PCN allergy. Outpatient prescription costs were estimated from $14 to $193/patient higher for PCN allergic patients. Total inpatient costs were less for patients without PCN allergy with average savings from $1145 to $4254/patient.

CONCLUSIONS

Evaluations of clinical and economic outcomes of PCN allergy are primarily observational and focus on inpatient populations. Long-term relationships between PCN allergy and clinical and economic outcomes are unknown.

Evaluation of Penicillin Allergy in the Hospitalized Patient: Opportunities for Antimicrobial Stewardship

PURPOSE OF REVIEW

Penicillin allergy is often misdiagnosed and is associated with adverse consequences, but testing is infrequently done in the hospital setting. This article reviews historical and contemporary innovations in inpatient penicillin allergy testing and its impact on antimicrobial stewardship.

RECENT FINDINGS

Adoption of the electronic medical record allows rapid identification of admitted patients carrying a penicillin allergy diagnosis. Collaboration with clinical pharmacists and the development of computerized clinical guidelines facilitates increased testing and appropriate use of penicillin and related β-lactams. Education of patients and their outpatient providers is the key to retaining the benefits of penicillin allergy de-labeling. Penicillin allergy testing is feasible in the hospital and offers tangible benefits towards antimicrobial stewardship. Allergists should take the lead in this endeavor and work towards overcoming personnel limitations by partnering with other health care providers and incorporating technology that improves the efficiency of allergy evaluation.

Penicillin and Beta-Lactam Hypersensitivity

Ten percent of patients report penicillin allergy, but more than 90% of these individuals can tolerate penicillins. Skin testing remains the optimal method for evaluation of possible IgE-mediated penicillin allergy and is recommended by professional societies, as the harms for alternative antibiotics include antimicrobial resistance, prolonged hospitalizations, readmissions, and increased costs. Removal of penicillin allergy leads to decreased utilization of broad-spectrum antibiotics, such as fluoroquinolones and vancomycin. There is minimal allergic cross-reactivity between penicillins and cephalosporins. IgE-mediated allergy to cephalosporins is usually side-chain specific and may warrant graded challenge with cephalosporins containing dissimilar R1 or R2 group side chains.

Clinical outcomes following inpatient penicillin allergy testing: A systematic review and meta-analysis

BACKGROUND

A documented penicillin allergy is associated with increased morbidity including length of hospital stay and an increased incidence of resistant infections attributed to use of broader-spectrum antibiotics. The aim of the systematic review was to identify whether inpatient penicillin allergy testing affected clinical outcomes during hospitalization.

METHODS

We performed an electronic search of Ovid MEDLINE/PubMed, Embase, Web of Science, Scopus, and the Cochrane Library over the past 20 years. Inpatients having a documented penicillin allergy that underwent penicillin allergy testing were included.

RESULTS

Twenty-four studies met eligibility criteria. Study sample size was between 24 and 252 patients in exclusively inpatient cohorts. Penicillin skin testing (PST) with or without oral amoxicillin challenge was the main intervention described (18 studies). The population-weighted mean for a negative PST was 95.1% [CI 93.8-96.1]. Inpatient penicillin allergy testing led to a change in antibiotic selection that was greater in the intensive care unit (77.97% [CI 72.0-83.1] vs 54.73% [CI 51.2-58.2], P<.01). An increased prescription of penicillin (range 9.9%-49%) and cephalosporin (range 10.7%-48%) antibiotics was reported. Vancomycin and fluoroquinolone use was decreased. Inpatient penicillin allergy testing was associated with decreased healthcare cost in four studies.

CONCLUSIONS

Inpatient penicillin allergy testing is safe and effective in ruling out penicillin allergy. The rate of negative tests is comparable to outpatient and perioperative data. Patients with a documented penicillin allergy who require penicillin should be tested during hospitalization given its benefit for individual patient outcomes and antibiotic stewardship.

Antimicrobial Stewardship Approaches in the Intensive Care Unit

Antimicrobial stewardship programs aim to monitor, improve, and measure responsible antibiotic use. The intensive care unit (ICU), with its critically ill patients and prevalence of multiple drug-resistant pathogens, presents unique challenges. This article reviews approaches to stewardship with application to the ICU, including the value of diagnostics, principles of empirical and definitive therapy, and measures of effectiveness. There is good evidence that antimicrobial stewardship results in more appropriate antimicrobial use, shorter therapy durations, and lower resistance rates. Data demonstrating hard clinical outcomes, such as adverse events and mortality, are more limited but encouraging; further studies are needed.

The Effect of Penicillin Allergy Testing on Future Health Care Utilization: A Matched Cohort Study

BACKGROUND

The effect that penicillin allergy testing has on future health care utilization is uncertain.

OBJECTIVE

Determine whether penicillin allergy testing affects future overall health care utilization as measured by outpatient department (OPD) visits, emergency department (ED) visits, and hospital days.

METHODS

Potential cases and control subjects were penicillin allergic Kaiser Permanente Southern California members who had at least 2 visits between 2010 and 2012 and at least 1 year of continuous health plan coverage before their index visit.

RESULTS

It was possible to match 308 (73.2%) of the potential cases to 1251 unique controls, on the basis of age, sex, weighted Charlson comorbidity index, drug class allergies, OPD visits, ED visits, and hospital days during the years before their index visit. Cases and controls were then followed for an average of 3.6 and 4.0 years, respectively. Based on results analyzed using a generalized linear mixed model, cases were estimated to have 0.09 fewer OPD visits (P < .001), 0.13 fewer ED visits (P = .29), and 0.55 fewer hospital days (P < .001) per health plan coverage year during follow-up compared with controls. Cases were exposed to more penicillins and first- and second-generation cephalosporins and less clindamycin and macrolides.

CONCLUSIONS

Penicillin allergy testing, primarily done in the setting of an outpatient Allergy consultation, was associated with significantly less health care utilization during 3.6+ years of follow-up and greater use of narrow-spectrum antibiotics. Penicillin allergy testing has a favorable cost-benefit ratio for the incremental cost of testing versus future health care utilization and improves antibiotic stewardship.

Tackling inpatient penicillin allergies: Assessing tools for antimicrobial stewardship

BACKGROUND

Reported penicillin allergy rarely reflects penicillin intolerance. Failure to address inpatient penicillin allergies results in more broad-spectrum antibiotic use, treatment failures, and adverse drug events.

OBJECTIVE

We aimed to determine the optimal approach to penicillin allergies among medical inpatients.

METHODS

We evaluated internal medicine inpatients reporting penicillin allergy in 3 periods: (1) standard of care (SOC), (2) penicillin skin testing (ST), and (3) computerized guideline application with decision support (APP). The primary outcome was use of a penicillin or cephalosporin, comparing interventions to SOC using multivariable logistic regression.

RESULTS

There were 625 patients: SOC, 148; ST, 278; and APP, 199. Of 278 ST patients, 179 (64%) were skin test eligible; 43 (24%) received testing and none were allergic. In the APP period, there were 292 unique Web site views; 112 users (38%) completed clinical decision support. Although ST period patients did not have increased odds of penicillin or cephalosporin use overall (adjusted odds ratio [aOR] 1.3; 95% CI, 0.8-2.0), we observed significant increased odds of penicillin or cephalosporin use overall in the APP period (aOR, 1.8; 95% CI, 1.1-2.9) and in a per-protocol analysis of the skin tested subset (aOR, 5.7; 95% CI, 2.6-12.5).

CONCLUSIONS

Both APP and ST-when completed-increased the use of penicillin and cephalosporin antibiotics among inpatients reporting penicillin allergy. While the skin tested subset showed an almost 6-fold impact, the computerized guideline significantly increased penicillin or cephalosporin use overall nearly 2-fold and was readily implemented.

Feasibility, Benefits, and Limitations of a Penicillin Allergy Skin Testing Service

OBJECTIVE

To critically examine the feasibility, benefits, and limitations of an inpatient penicillin skin testing service and how pharmacists can be utilized.

DATA SOURCES

A PubMed search was performed from July 2016 through September 2016 using the following search terms: penicillin skin testing, penicillin allergy, β-lactam allergy. Additional references were identified from a review of literature citations.

STUDY SELECTION AND DATA EXTRACTION

All English-language studies assessing the use of penicillin skin testing as well as management and clinical outcomes of patients with a β-lactam allergy were evaluated.

DATA SYNTHESIS

The prevalence of people self-identifying as penicillin allergic ranges from 10% to 20% in the United States. Being improperly labeled as penicillin allergic is associated with higher health care costs, worse clinical outcomes, and an increased prevalence of multidrug-resistant infections. Penicillin skin testing can be a tool used to clarify penicillin allergies and has been demonstrated to be a successful addition to antimicrobial stewardship programs in multiple health care settings. Prior to implementing a penicillin skin testing service, institutions will need to perform a feasibility analysis of who will supply labor and accept the financial burden as well as identify if the positive benefits of a penicillin skin testing service overcome the limitations of this diagnostic test.

CONCLUSION

We conclude that institutions with high percentages of patients receiving non-β-lactams because of penicillin allergy labels would likely benefit the most from a penicillin skin testing service.

A Proactive Approach to Penicillin Allergy Testing in Hospitalized Patients

BACKGROUND

Penicillin allergy testing is underutilized in inpatients despite its potential to immediately impact antibiotic treatment. Although most tested patients are able to tolerate penicillin, limited availability and awareness of this tool leads to the use of costly and harmful substitutes.

OBJECTIVE

We established an inpatient service at a large academic hospital to identify and test patients with a history of penicillin allergy with the goals of removing inaccurate diagnoses, reducing the use of beta-lactam alternatives, and educating patients and clinicians about the procedure.

METHODS

Eligible inpatients were flagged daily through the electronic medical record and prioritized via a specialized algorithm. A trained clinical pharmacist performed penicillin skin tests and challenges preemptively or by provider request. Clinical characteristics and antibiotic use were analyzed in tested patients.

RESULTS

A total of 1203 applicable charts were detected by our system leading to 252 direct evaluations over 18 months. Overall, 228 subjects (90.5%) had their penicillin allergy removed. Of these, 223 were cleared via testing and 5 by discovery of prior penicillin tolerance. Among patients testing negative, 85 (38%) subsequently received beta-lactams, preventing 504 inpatient days and 648 outpatient days on alternative agents.

CONCLUSIONS

Penicillin allergy testing using a physician-pharmacist team model effectively removes reported allergies in hospitalized patients. The electronic medical record is a valuable asset for locating and stratifying individuals who benefit most from intervention. Proactive testing substantially reduces unnecessary inpatient and outpatient use of beta-lactam alternatives that may otherwise go unaddressed.

Diagnosis of allergy against beta-lactams in primary care: prevalence and diagnostic criteria

BACKGROUND

Secondary care studies showed that a recorded allergy to beta-lactams could not be confirmed by valid allergy testing in >85% of cases. In daily practice, recorded beta-lactam allergies probably cause prescription of secondary choice antibiotics. This overrating of beta-lactam allergy hampers appropriate use of narrow spectrum antibiotic and generates unnecessary cost and bacterial resistance.

OBJECTIVE

To assess registration and over diagnosis of allergies against beta-lactams in Dutch primary care.

METHODS

A retrospective cohort study in 8288 primary care subjects was performed. Patients with recorded allergy were identified through International Classification for Primary Care coding. Signs and symptoms of the recorded allergic reaction and patient's characteristics were extracted from patient's files and patients were sent a questionnaire. The probability of allergy was based on a composite reference standard that was scored by two authors independently.

RESULTS

One hundred sixty-three subjects had a recorded allergy (2.0%). In 51.5% of cases, no characteristics of the recorded allergic reaction were reported in patients' medical files. Based on our composite reference standard, allergy was excluded in 19 subjects (11.7%). Risk factors for allergy registration were female gender, age <4 years, and the comorbidities-asthma, allergies and skin disorders.

CONCLUSIONS

The prevalence of recorded allergy against beta-lactam antibiotics in a large Dutch primary care centre was 2%. Due to lack of registration of accompanying signs and symptoms of the recorded allergy, this diagnosis is uncertain in most patients. Better documentation and classification by a screening algorithm of future possible allergic reactions to beta-lactams are needed in primary care.

Factors associated with negative histamine control for penicillin allergy skin testing in the inpatient setting

BACKGROUND

Identification of factors adversely affecting the utility of allergy skin testing is important in optimizing patient care. Inpatient penicillin skin test data from 1997 through 2007 demonstrate that up to 20% of attempted penicillin skin tests are indeterminate owing to a negative histamine test response, despite exclusion of H1 antagonists. Critical illness, vasopressors, steroid use, and psychotropic medications have been postulated to influence outcomes, but large studies are lacking.

OBJECTIVE

To identify factors associated with a negative histamine test response for the inpatient setting.

METHODS

Fifty-two cases were identified with a negative histamine response after penicillin skin testing in the absence of antihistamine therapy for 72 hours before testing. One hundred twenty-five controls with a normal histamine response were randomly selected from same population. Independent variables assessed included stay in the intensive care unit (ICU), skin color, diabetes, age, use of vasopressors, H2 blocker, steroids, other immunosuppressive drugs, thyroid replacement, proton pump inhibitors, diuretics, 5 categories of psychotropic medications, and amiodarone.

RESULTS

Mean age was 68 years for cases vs 60 years for controls (P = .002). Bivariate analysis showed ICU stay was more frequent in cases than in controls (73.1% vs 33.6%, P < .001). Regression analysis yielded odds ratios (ORs) of 8.18 (95% confidence interval 3.22-20.76) for ICU status, 3.76 (1.30-10.92) for systemic corticosteroids, and 4.90 (1.17-20.62) for H2 blockers as associated with lack of histamine response. For every additional year in age, there was increase in the OR of 1.04 (1.01-1.07).

CONCLUSION

Regression analysis supports ICU stay during skin testing as associated with a high OR for a negative histamine response independent of age. Systemic corticosteroids, H2 blockers, and older age are associated with a significant OR for a negative histamine response. This is one of largest studies on factors associated with a negative histamine response for the inpatient setting and has significant implications for clinical practice.

Antimicrobial stewardship's new weapon? A review of antibiotic allergy and pathways to 'de-labeling'

PURPOSE OF REVIEW

The continued emergence of multiresistant pathogens and widespread antimicrobial use has led to a greater emphasis on antimicrobial stewardship programs. Concurrently, an increased awareness of the rising number of antibiotic allergy labels and impact on antimicrobial use has surfaced. The integration of antibiotic allergy de-labeling and antimicrobial stewardship programs may be a pathway worthy of further focus and investigation.

RECENT FINDINGS

Recent literature has evaluated the efficacy of antibiotic allergy management (historical de-labeling, in-vitro testing, skin prick testing, intradermal testing, and oral challenges) and impact of antibiotic allergy labels on patient outcome. The importance of true and perceived antibiotic allergy cross-reactivity in the setting of β-lactam allergies has been highlighted. The impact of dedicated antibiotic allergy de-labeling clinics, inpatient antibiotic allergy testing, and integrated antimicrobial stewardship programs has been recently appraised.

SUMMARY

More recent literature supports that appropriate antibiotic allergy in-vitro and in-vivo testing and subsequent antibiotic allergy de-labeling, particularly in regard to β-lactams, can decrease broad-spectrum antibiotic use, costs, patient length of stay, and mortality. Integration of antibiotic allergy management into the decision support systems of inpatient and outpatient antimicrobial stewardship programs represents an important opportunity to further improve measured outcomes from antibiotic utilization.

Health care use and serious infection prevalence associated with penicillin "allergy" in hospitalized patients: A cohort study

BACKGROUND

Penicillin is the most common drug "allergy" noted at hospital admission, although it is often inaccurate.

OBJECTIVE

We sought to determine total hospital days, antibiotic exposures, and the prevalence rates of Clostridium difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) in patients with and without penicillin "allergy" at hospital admission.

METHODS

We performed a retrospective, matched cohort study of subjects admitted to Kaiser Foundation hospitals in Southern California during 2010 through 2012.

RESULTS

It was possible to match 51,582 (99.6% of all possible cases) unique hospitalized subjects with penicillin "allergy" to 2 unique discharge diagnosis category-matched, sex-matched, age-matched, and date of admission-matched control subjects each. Cases with penicillin "allergy" averaged 0.59 (9.9%; 95% CI, 0.47-0.71) more total hospital days during 20.1 ± 10.5 months of follow-up compared with control subjects. Cases were treated with significantly more fluoroquinolones, clindamycin, and vancomycin (P < .0001) for each antibiotic compared with control subjects. Cases had 23.4% (95% CI, 15.6% to 31.7%) more C difficile, 14.1% (95% CI, 7.1% to 21.6%) more MRSA, and 30.1% (95% CI, 12.5% to 50.4%) more VRE infections than expected compared with control subjects.

CONCLUSIONS

A penicillin "allergy" history, although often inaccurate, is not a benign finding at hospital admission. Subjects with a penicillin "allergy" history spend significantly more time in the hospital. Subjects with a penicillin "allergy" history are exposed to significantly more antibiotics previously associated with C difficile and VRE. Drug "allergies" in general, but most those notably to penicillin, are associated with increased hospital use and increased C difficile, MRSA, and VRE prevalence.

Treatment of patients with a history of penicillin allergy in a large tertiary-care academic hospital

BACKGROUND

Prescribing antibiotics to patients with a history of penicillin allergy is common in clinical practice. Opting for non-beta-lactam antibiotics has its inconveniences and is often unnecessary, because most of these patients are in fact not allergic.

OBJECTIVE

This study aimed to determine how physicians in a large Canadian tertiary-care academic hospital without allergists on staff treat patients with a history of penicillin allergy.

METHODS

A retrospective study was conducted during a 1-year period among all patients hospitalized in the intensive care unit, coronary care unit, and internal medicine wards. Files of patients with a record of penicillin allergy were reviewed to assess the need for antibiotics during their hospitalization and the decision-making process underlying the choice of antibiotic. The additional costs of alternative antibiotics were calculated.

RESULTS

The files of 1738 patients admitted over a 1-year period were hand reviewed. A history of penicillin allergy was found in 172 patients (9.9%). The allergic reaction was described in only 30% of cases and left unmentioned in 20.7%. Beta-lactam antibiotics were used on 56 occasions despite a history of penicillin allergy. The use of alternative antibiotics in place of the beta-lactam standard of care carried an additional cost of $15,672 Canadian.

CONCLUSION

Alleged penicillin allergy is common among hospitalized patients and leads to substantial additional costs. Poor documentation of penicillin allergy likely reflects a lack of knowledge on this issue in the medical community, which impairs optimal treatment of these patients. Increased education on this matter is needed, and allergists on staff could be part of the solution.

Drug allergy: an updated practice parameter

Adverse drug reactions (ADRs) result in major health problems in the United States in both the inpatient and outpatient setting. ADRs are broadly categorized into predictable (type A and unpredictable (type B) reactions. Predictable reactions are usually dose dependent, are related to the known pharmacologic actions of the drug, and occur in otherwise healthy individuals, They are estimated to comprise approximately 80% of all ADRs. Unpredictable are generally dose independent, are unrelated to the pharmacologic actions of the drug, and occur only in susceptible individuals. Unpredictable reactions are subdivided into drug intolerance, drug idiosyncrasy, drug allergy, and pseudoallergic reactions. Both type A and B reactions may be influenced by genetic predisposition of the patient

Allergic and hypersensitivity reactions in the intensive care unit

Hypersensitivity reactions are defined as immunologically based adverse reactions to chemicals or medicinal agents. These reactions are common in the intensive care unit and can present as a simple, mildly symptomatic rash or as life-threatening anaphylactic reactions. Hypersensitivity reactions have traditionally been classified as types I to IV reactions based on the underlying immune mechanisms, although the clinical relevance of the classification is unclear, and new subtypes to this system have been recently proposed. Given the immunologic and often unpredictable nature of these reactions, avoidance or prevention is not a feasible option. Therefore, management has primarily consisted of withdrawal of potential offending agents, supportive therapy, symptomatic management, and, in some specific examples, targeted pharmacotherapy. This article outlines the background and types of hypersensitivity reactions and provides descriptions and management strategies when applicable to common types of hypersensitivity reactions encountered in the intensive care unit.

The current practice of skin testing for antibiotics in Korean hospitals

BACKGROUND/AIMS

Antibiotic skin testing is a useful procedure for identifying patients with IgE-mediated hypersensitivity to antibiotics. The procedures, however, have not been standardized, and the testing is performed with diverse protocols in Korean hospitals wards. Thus, we examined the current practice of antibiotic skin testing in Korea.

METHODS

We sent questionnaires to 12 allergists working in secondary or tertiary referral hospitals and collected them by e-mail or fax. The questionnaire included items such as the types and concentrations of the tested antibiotics, the methods of antibiotic skin testing, and the interpretation of the results.

RESULTS

All hospitals responded to the questionnaire. The antibiotic skin testing protocols were variable, inconsistent, and differed with regard to the type and concentrations of antibiotics, the volume injected, and the interpretation of the results. Moreover, the protocols differed from the commonly recommended procedures in the medical literature.

CONCLUSIONS

Standardized guidelines for antibiotic skin testing are needed for the safe and effective use of antibiotics in Korea.

Self-reported antibiotic allergy incidence and prevalence: age and sex effects

BACKGROUND

Data on the prevalence and incidence of adverse reactions to antibiotics in outpatient populations are rare. These events are commonly called "allergy" when noted in the medical record.

OBJECTIVES

Determine the prevalence and incidence of allergy, as recorded in the medical record, to the most commonly used antibiotic classes in a large outpatient population using health care in the United States during 2007.

METHODS

Data for drug allergy and antibiotic use were extracted from the electronic health records of 411,543 patients cared for by Kaiser Permanente in San Diego County who had at least one outpatient visit during 2007. Outpatient antibiotic utilization data was obtained for each year between 1995 and 2007. Penicillins, sulfas, cephalosporins, tetracyclines, macrolides, and quinolones were the classes of antibiotics evaluated.

RESULTS

Antibiotics account for a majority of drug allergy entries. Antibiotic classes with higher historical use have higher allergy prevalence. Female patients use more antibiotics than males, and have higher allergy prevalence rates for all classes of antibiotics. There is a steady increase in antibiotic allergy prevalence with aging for both sexes. Females have higher allergy incidence rates for all classes of antibiotics. Antibiotic allergy incidence in female patients is highest for sulfas, 3.4%, compared with 1%-1.5% for all other classes of antibiotics. Antibiotic allergy incidence in males also is highest for sulfas, 2.2%, compared with 1.1% for penicillins and 0.5%-0.6% for all other classes of antibiotics.

CONCLUSIONS

Female sex, use, and increasing age are the primary factors that account for higher antibiotic allergy prevalence. Antibiotic allergy incidence is highest with sulfa class antibiotics.

Preoperative evaluation of patients with history of allergy to penicillin: comparison of 2 models of practice

OBJECTIVE

To study whether allergy consultation and penicillin allergy skin testing affects the selection of antibacterial prophylaxis perioperatively in surgical patients with history of allergy to penicillin (HOAP).

PATIENTS AND METHODS

From January 1 through June 30, 2004, we compared 2 different models of practice at our institution. At the Preoperative Evaluation Clinic (POEC), all patients with HOAP are evaluated by an allergist and undergo skin testing for allergy to penicillin. At other (non-POEC) preoperative evaluation settings (OPES), patients with HOAP do not undergo allergy consultation and penicillin skin testing before surgery. Of the 4889 patients screened at the POEC during the study period, 412 consecutive patients with HOAP were included in the study. Of the 416 patients screened at OPES, 69 consecutive patients with HOAP were studied. Logistic regression was used to assess whether allergy consultation was associated with the choice of antibiotic for antibacterial prophylaxis perioperatively, after adjusting for age, sex, and type of surgery.

RESULTS

Perioperative cephalosporin use was greater among patients screened at POEC vs those screened at OPES (70% vs 39%, P<.001 unadjusted; P=.04 adjusted for age, sex, and type of surgery). Vancomycin use was lower for patients screened at POEC vs those screened at OPES (10% vs 28%, P<.001 unadjusted; P=.03 adjusted).

CONCLUSION

For patients with HOAP, evaluation at the POEC was associated with increased use of cephalosporin and decreased use of vancomycin.

Penicillin skin testing in patients with a history of beta-lactam allergy

BACKGROUND

Vancomycin and fluoroquinolones are commonly used in patients with a history of penicillin allergy.

OBJECTIVE

To determine the safety and utility of penicillin skin testing (PST).

METHODS

Retrospective study of patients with a history of penicillin allergy between April 1, 1999, and September 30, 2004. Penicillin skin testing was performed by means of standard methods using benzylpenicilloyl-polysine, penicillin G, and histamine and saline controls.

RESULTS

Of 596 patients studied, 25.3% were outpatients, 50.3% were inpatients, and 24.3% were intensive care unit patients. The most common antibiotics used during the time of PST were vancomycin and fluoroquinolones. Results of PST were negative in 88.4% of patients, positive in 8.2%, and indeterminate in 3.4%. One patient (0.17%) developed urticaria immediately after PST. Fifty-five percent of patients with negative PST results were changed to a beta-lactam drug, more frequently in the intensive care unit vs the outpatient setting (70.3% vs 8.6%; P < .001) and in adults vs patients younger than 18 years (58.6% vs 8.1%; P < .001). A beta-lactam antibiotic was used in 290 patients with negative PST results. Of the patients given beta-lactam antibiotics, 5 (1.7%) had adverse reactions: 2 had hives after 16 and 20 days of therapy, 1 had a nonspecific rash after 17 days of therapy, 1 had flushing and urticaria 3 hours after a test dose of piperacillin-tazobactam, and 1 had a pruritic rash after 12 hours of therapy.

CONCLUSIONS

Patients with a history of penicillin allergy can safely use beta-lactam drugs if negative PST results.

Anaphylactic and anaphylactoid causes of angioedema

Anaphylactic and anaphylactoid (pseudoallergic) reactions can be expected to occur with greater frequency as the number of immunomodulators are employed. The immune system will become sensitized to these new therapeutic agents or there may be first-dose reactions depending on the pathogenetic mechanism involved. Physicians should review their office or procedure room emergency preparedness protocols and medications. The lack of penicillin major and minor determinants for penicillin testing has made management of penicillin and cephalosporin allergic patients more complicated. In the absence of skin-testing materials, test-challenges will be necessary and performed with less comfort because of not knowing the current level of immunologic sensitization to penicillin. The indication for readministration of any incriminated medication/therapeutic agent should be reviewed. Often, there are not suitable alternatives. Various approaches have been presented to permit safer readministration of essential medications or diagnostic agents to prevent episodes of anaphylaxis or upper airway angioedema.

Predictors of long-term mortality in patients with ventilator-associated pneumonia

PURPOSE

To determine the long-term outcome of ventilator-associated pneumonia (VAP) and identify factors associated with increased mortality.

METHODS

We retrospectively studied 671 patients with VAP admitted to an intensive care unit between 1994 and 2000. We determined long-term and out-of-hospital mortality for these patients.

RESULTS

The in-hospital mortality was 42.3%; 19.8% of patients had concomitant bacteremia, the mortality was 59.7% versus 38.0% for those without bacteremia (P <.001). The factors associated with increased hospital mortality by univariable analysis were: diagnosis on admission, the need of vasopressors during the stay in the intensive care unit, not undergoing a tracheostomy, the absence of fever, the presence of concomitant bacteremia, and renal failure or the need for dialysis. Patients transferred from an outside hospital and patients with normal serum bicarbonate, serum total bilirubin <2 mg/dL, and platelets >120x4> 10(3)/microL had a lower in-hospital mortality. All of these factors except bilirubin level, platelet count, transfer from outside hospital, and serum bicarbonate remained significant on multivariable analysis. The estimated mortality at 1, 3 and 5 years is 25.9% (95% confidence interval [CI], 20.2-30.1%), 33.6% (95% CI, 27.4-39.2%) and 44.7% (95% CI, 38.1-50.6%), respectively.

CONCLUSIONS

VAP is associated with a high rate of hospital and long-term mortality. The presence of bacteremia is associated with a high mortality. The 5-year estimated mortality of the survivors is less than 50%.

Decision-Making Analysis for Selection of Antibiotic Treatment in Intra-Abdominal Infection Using Preference Measurements

BACKGROUND

Antimicrobial therapy of abdominal infections is important to the prognosis of affected patients. The choice of antimicrobial therapy must consider effectiveness, safety, cost, and antibiotic resistance, among numerous factors. However, in reality, decisions are made assuming bioequivalence between regimens, without considering the specific attributes of any particular regimen. The objective was to determine the best antibiotic regimen for patients with community-acquired abdominal infection on the basis of a decision analysis that included effectiveness as well as safety, measured as adverse effects.

METHODS

A decision tree was built using information from a systematic review of the literature on the effectiveness of antimicrobial regimens tested in randomized clinical trials (RCTs) and the frequency and severity of adverse effects. The quality of the articles was assessed with the Oxford criteria for RCTs. The main outcome was preferences reported by surgeons, measured on a numeric scale. Preferences were obtained using a standard survey that reported each adverse effect with its respective intensity, reversibility, sequelae, duration of symptoms, and necessity for change of antibiotic. Each of the surgeons had to assign a value blindly from 0 to 10, where 10 was the most severe. A sensitivity analysis was conducted varying the frequency of adverse effects.

RESULTS

The regimens analyzed were amikacin-metronidazole, amikacin-clindamycin, ciprofloxacin-metronidazole, ampicillin-sulbactam, ceftriaxone-metronidazole, piperacillin-tazobactam, and ertapenem. The perceived severity of adverse effects reported were: Acute neuromuscular blockade (8.0), severe allergic reaction (7.5), ototoxicity (7.4), nephrotoxicity (7.1), antibiotic-associated colitis (7.0), peripheral neuropathy (5.3), general neurological symptoms (4.9), gastrointestinal symptoms (3.1), and other general symptoms (2.6). Favored regimens were ceftriaxone-metronidazole (1.15), ampicillin-sulbactam (1.24), piperacillin-tazobactam (1.27) and ertapenem (1.28). These strategies dominated the other therapeutic schemes. Sensitivity analysis showed no changes in the dominance reported when the frequency of adverse effects was maintained in the known clinical range.

CONCLUSIONS

Antibiotic regimens that contain aminoglycosides are not bioequivalent to those without aminoglycosides when effectiveness and adverse effects are considered simultaneously. Antibiotic regimens that do not use aminoglycosides must be the first line of treatment for abdominal sepsis acquired in the community.

Clinical history as a predictor of penicillin skin test outcome

BACKGROUND

Up to 10% of the population reports an "allergy" to penicillin, whereas approximately 1.1% has positive penicillin skin test results. Where penicillin skin tests are unavailable, some have advocated using history to decide whether to use a penicillin-related antibiotic.

OBJECTIVE

To determine if clinical history predicts penicillin skin test results.

METHOD

Retrospective medical record review of 94 consecutive patients who had previously taken penicillin referred for penicillin allergy. Case histories were taken, penicillin skin tests performed, and an oral challenge recommended if skin test results were negative.

RESULTS

Of 91 cases studied, the average patient age was 27 years (range, 6 months to 82 years; 36% female). Fifty-two (57%) experienced hives as their main adverse reaction. Sixteen (18%) had at least 1 positive test result. Of this group, 9 had hives as their main symptom, whereas 1 had respiratory problems and 1 had angioedema. Most patients with positive skin test results had experienced their reaction at least 3 years ago. Regression analysis showed that age, sex, and clinical history, including type of reaction, time of reaction after penicillin ingestion, or time since the last reaction, were not associated with skin test positivity. Seventy-two (96%) of the 75 patients who had negative skin test results underwent oral challenge. Seventy had negative challenge results. The negative predictive value of a negative penicillin skin test result was 97%.

CONCLUSION

Clinical history was not predictive of subsequent penicillin skin test results.

Penicillin skin testing in pregnant women with a history of penicillin allergy and group B streptococcus colonization

BACKGROUND

The safety and utility of penicillin skin testing (PST) in pregnant women with a history of penicillin allergy and group B streptococcus (GBS) colonization have not been studied.

OBJECTIVE

To document the safety and utility of PST in pregnant women with a history of penicillin allergy and GBS colonization.

METHODS

Pregnant GBS culture-positive women with a history compatible with an IgE-mediated or unknown reaction to a penicillin-class antibiotic were recruited for PST. If PST results were negative, penicillin-class antibiotics were recommended for GBS prophylaxis. Adverse reactions associated with PST or antibiotic use from the time of PST through delivery and 6 months post partum were reported.

RESULTS

In 56 enrolled patients, there were only 2 mild adverse reactions (4%) associated with PST and 3 positive PST results (5%). Of the 53 PST-negative patients, 47 (89%) received at least 1 course of penicillin. There were 2 delayed-onset rashes associated with the use of intrapartum penicillins and 1 immediate-onset rash with intrapartum vancomycin therapy in a PST-positive woman. There were 7 reactions (6%) associated with 122 antibiotic courses administered.

CONCLUSIONS

Penicillin skin testing can be performed safelyin pregnant women and, if the results are negative, allows penicillins to be used safely at delivery for GBS prophylaxis.

Clinical outcomes of penicillin skin testing

BACKGROUND

Penicillin or cephalosporin allergy is a common problem with antibiotic drug prescribing in hospitalized patients.

OBJECTIVES

To study the various clinical outcomes of penicillin skin testing (PST) in a community teaching hospital and to determine the percentage of patients who have an antibiotic drug modification after PST.

METHODS

This study was a retrospective medical record review of all inpatients who underwent PST in 6.6 years. Information was collected on 101 patients using a detailed data collection form. Data were summarized using descriptive statistics, including frequencies and percentages.

RESULTS

Of the 101 patients who underwent PST, 92 had a negative result and 5 had a positive result; in 4 patients the test result was indeterminate. There was a 96% (67/70) reduction in the use of vancomycin and a 96% (23/24) reduction in the use of fluoroquinolones after PST in patients with negative results. Forty-nine percent of patients with negative PST results were administered a penicillin-based drug, and 48% were given a cephalosporin. Cultures were positive most commonly for Staphylococcus aureus and enterococcus. There were no serious adverse reactions to PST or to the use of penicillins or cephalosporins after a negative PST result.

CONCLUSIONS

Penicillin skin testing lowered the use of vancomycin and fluoroquinolones and increased the use of penicillin-based drugs and cephalosporins in patients with a history of beta-lactam drug allergies.

Drug hypersensitivity

Allergic drug reactions compose a small percentage of ADRs, yet they are commonly encountered in clinical practice, and physicians are taught routinely to question patients about these reactions during history taking. Among antibiotics, the immunochemistry of penicillins has been elucidated,leading to the development of validated skin test reagents to diagnose type 1 allergy. Currently, the temporary commercial unavailability of Pre-Pen makes accurate penicillin skin testing impossible; however, this important skin test reagent is expected to become available sometime in 2006. Type 1 allergies to most other drugs lack comparable diagnostic tests, and their diagnosis is therefore driven by the patient's history. When readministration of medications to which patients report previous reactions is indicated, it may be almost always successfully accomplished by means of either graded challenge or desensitization.