Comparison of Open-Access, Trough-Only Online Calculators Versus Trapezoidal Method for Calculation of Vancomycin Area Under the Curve (AUC)

BACKGROUND

Vancomycin area-under-the-curve (AUC) monitoring is associated with reduced nephrotoxicity but may increase cost and workload for personnel compared to trough monitoring.

OBJECTIVE

The purpose of this study was to compare the accuracy of vancomycin AUC calculated by open-access, online, trough-only calculators to AUCs calculated by the trapezoidal method (TM) using peak and trough concentrations.

METHODS

This retrospective, multi-center study included adults ≥18 years old with stable renal function who received vancomycin with steady-state peak and trough concentrations. Areas under the curve calculated by TM were compared to AUCs calculated by 3 online calculators using trough-only options for calculation: ClinCalc, VancoVanco, and VancoPK. The primary outcome was actual difference in AUC between TM and the online calculators. Secondary outcomes were percent difference in AUC and clinical alignment in dose adjustments between methods.

RESULTS

Seventy patients were included for analysis. There was a statistically significant difference in AUC between TM and ClinCalc (median actual difference: -52, P < 0.001) and VancoVanco (median actual difference: 95, P < 0.001), whereas there was no significant difference between TM and VancoPK (median actual difference: -0.8, P = 0.827). Discordant dose adjustments were indicated when comparing ClinCalc, VancoVanco, and VancoPK to TM in 28%, 36%, and 12% of cases, respectively.

CONCLUSION

The AUC calculator most closely aligned with TM was VancoPK, whereas other included calculators were statistically different. Owing to the cost and complexity of obtaining multiple levels, our findings support using a single steady-state trough using VancoPK as an alternative to TM for calculation of vancomycin AUC.

Evaluation of an Opt-Out Protocol for Antibiotic De-Escalation in Patients With Suspected Sepsis: A Multicenter, Randomized, Controlled Trial

BACKGROUND

Sepsis guidelines recommend daily review to de-escalate or stop antibiotics in appropriate patients. This randomized, controlled trial evaluated an opt-out protocol to decrease unnecessary antibiotics in patients with suspected sepsis.

METHODS

We evaluated non-intensive care adults on broad-spectrum antibiotics despite negative blood cultures at 10 US hospitals from September 2018 through May 2020. A 23-item safety check excluded patients with ongoing signs of systemic infection, concerning or inadequate microbiologic data, or high-risk conditions. Eligible patients were randomized to the opt-out protocol vs usual care. Primary outcome was post-enrollment antibacterial days of therapy (DOT). Clinicians caring for intervention patients were contacted to encourage antibiotic discontinuation using opt-out language. If continued, clinicians discussed the rationale for continuing antibiotics and de-escalation plans. To evaluate those with zero post-enrollment DOT, hurdle models provided 2 measures: odds ratio of antibiotic continuation and ratio of mean DOT among those who continued antibiotics.

RESULTS

Among 9606 patients screened, 767 (8%) were enrolled. Intervention patients had 32% lower odds of antibiotic continuation (79% vs 84%; odds ratio, 0.68; 95% confidence interval [CI], .47-.98). DOT among those who continued antibiotics were similar (ratio of means, 1.06; 95% CI, .88-1.26). Fewer intervention patients were exposed to extended-spectrum antibiotics (36% vs 44%). Common reasons for continuing antibiotics were treatment of localized infection (76%) and belief that stopping antibiotics was unsafe (31%). Thirty-day safety events were similar.

CONCLUSIONS

An antibiotic opt-out protocol that targeted patients with suspected sepsis resulted in more antibiotic discontinuations, similar DOT when antibiotics were continued, and no evidence of harm.

CLINICAL TRIALS REGISTRATION

NCT03517007.

961. Pandemic Hits: Evaluation of an Antimicrobial Stewardship Program Website for Hospital Communication During the COVID-19 Pandemic

Background

Antibiotic Stewardship Programs (ASPs) assist front-line clinicians in synthesizing emerging data and establishing best practices. Our ASP team directly maintained and edited an internal web application, Duke CustomID^®, to disseminate updated guideline, policy, and drug information during COVID-19. We aimed to describe website engagement and maintenance during the dynamic pandemic period.

Methods

We performed a descriptive, time-series analysis using Google Analytics software to measure engagement with Duke CustomID^® during a 1-year pre-pandemic period through the Omicron surge: January 2019 to March 2022. We measured total page views (or “hits”), COVID-specific page hits, and days requiring COVID-specific page edits by week. Given fluctuations in hospitalization rates, we defined the primary outcome as the rate of hits divided by total hospitalizations. Weekly data were assessed graphically with positive COVID tests and COVID hospitalizations. We used negative binomial regression to quantify the association between COVID hospitalizations and hit rates and to trend engagement over time, adjusted for seasonality. We stratified data by COVID page and calculated a hit/edit ratio.

Results

Engagement with CustomID® increased during the pandemic period, especially during surges (Figure). Hits in the pre-pandemic period were median 1707 (range 1165-2354) per week, and hit rates median 1.95 per hospitalization (range 1.40-2.86). Peaks were observed in March 2020 (hit rate 4.59) and January 2022 (hit rate 3.87). On average, for every 100 COVID hospitalizations, the hit rate increased by 0.08 (0.004-0.16, p=0.04). Engagement slowly increased over the study period (relative rate week 1 versus 170: 1.15, 95% confidence interval 1.02-1.28, p=0.02). COVID page edits per week had a median of 2 (range 0-12). Adult Inpatient Guidelines and COVID Monoclonal Antibody pages had highest use (Table).

Duke CustomID Hits and Maintenance Efforts over the Pandemic

Top: COVID-specific CustomID hits per week (Green), Positive COVID tests per week (Blue) over time

Middle: Total custom ID page hits relative to total hospitalizations per week (teal), COVID hospitalizations (Red)

Bottom: Number of edits to COVID-specific CustomID pages per week, stratified by management pages and drug pages

Several dates of significance are highlighted including the Emergency Use Authorizations (EUA) for remdesivir, the COVID Vaccines, and Paxlovid

Duke CustomID COVID-19 Page Hits and Edits

COVID specific pages on Duke CustomID with total hits, edits, and ratio over the pandemic

Conclusion

Our ASP’s website was a highly utilized, practical tool for disseminating practice-changing information during the pandemic. Use increased over time and especially during surges. An electronic reference customized for local practice and rapidly updated by ASPs offers critical support for front-line clinicians.

Disclosures

Martha B. Adams, M.D., Custom Clinical Decision Support, Inc: Board Member|Custom Clinical Decision Support, Inc: Ownership Interest Richard H. Drew, PharmD MS, American College of Clinical Pharmacists: Publication royalties|Takeda: Advisor/Consultant|UpToDate: publication royalties Rebekah W. Moehring, MD, MPH, FIDSA, FSHEA, UpToDate, Inc.: Author Royalties Michael J. Smith, M.D., M.S.C.E, Merck: Grant/Research Support|Pfizer: Grant/Research Support.

Impact of COVID ‐19 pandemic on pharmacist‐led allergy assessments and penicillin skin testing

Allergy assessments and penicillin skin testing are associated with reductions in high‐Clostridioides difficile infection (CDI)‐risk antibiotic use and lower hospital‐acquired CDI rates; however, these activities require substantial personnel and resource allocation. Recently, many antimicrobial stewardship programs’ (ASPs) focus shifted towards supporting the COVID‐19 pandemic response. We evaluated the impact of the COVID‐19 pandemic on a pharmacist‐led allergy assessment and penicillin skin testing program. Patients undergoing allergy assessment and/or penicillin skin testing (PST) from 1 January 2017 through 30 April 2021 were included for review. Monthly PST and allergy assessment rates were calculated and defined as the number of PSTs or allergy assessments per 1000 unique patient encounters for each month, respectively. The study used interrupted time series regression to assess potential level and slope changes in allergy assessments and PSTs during the pandemic. 200 058 total inpatient encounters by 188 867 unique patients occurred during the study period. ASP performed 918 allergy assessments and 204 PSTs. The local onset of the SARS‐CoV‐2 pandemic during March 2020 was associated with significant level reductions in allergy assessments and PSTs. Additional responsibilities added to the ASP team during the COVID‐19 pandemic limited the ability to perform core antimicrobial stewardship activities with proven patient care benefits.

1107. Vancomycin AUC Dosing: Is One Concentration in the Hand Worth Two in the Bush?

Background

Recent guidelines recommend a transition from trough-based to area-under the curve-based (AUC) monitoring for vancomycin for serious invasive methicillin-resistant Staphylococcus aureus infections. Due to the challenges of performing AUC monitoring in clinical practice, this study sought to compare the accuracy of an AUC calculated from two points using trapezoidal calculations and from a single steady-state trough combined with population assumptions.

Methods

This prospective cohort analysis included hospitalized patients with stable renal function from 10.2020 to 12.2020 with two vancomycin concentrations obtained at steady-state during a single dosing interval. For each patient, AUC was calculated via trapezoidal equations utilizing peak and trough concentrations (P/T) and using the trough concentration (T) combined with population volume of distribution. Appropriate concentrations were defined as a peak at least 2 hours after the end of the infusion and a trough within one hour of the next dose. The percent and actual differences were calculated between the P/T and T AUC assessments for each patient. A patient level review was independently conducted by two clinical pharmacists to evaluate if a change in dosing would have been made according to AUC estimation methodology.

Results

Thirty-one patients had appropriate steady-state P/T obtained. Baseline demographics are shown in Table 1 with the majority of patients being overweight with normal renal function. The mean calculated AUC for both groups was similar, P/T 544.8 and T 549.8. The mean and median percent differences were 1.85% and 0.65%, with a standard deviation of 7.3% and an apparent normal distribution (Figure 1, p = 0.94 by Shapiro’s test). The median absolute difference in AUC was 25.82 mg*h/L between methodologies. Both methods would have resulted in the same modification to the vancomycin regimen based on patient level chart review.

Conclusion

The single-trough method performed similarly to the more laborious P/T method. No patient would have received a dose adjustment based on the two different AUC estimation methods. The single-trough method may represent a resource and workflow conscious AUC estimation method for patients meeting population assumptions.

Disclosures

All Authors: No reported disclosures

14. Effects of an Opt-Out Protocol for Antibiotic De-escalation among Selected Patients with Suspected Sepsis: The DETOURS Trial

Background

Sepsis guidelines recommend daily review to de-escalate or stop antibiotics in appropriate patients. We conducted a randomized controlled trial (NCT03517007) of an opt-out protocol to decrease unnecessary antibiotics in selected patients with suspected sepsis.

Methods

We evaluated non-ICU adults remaining on broad-spectrum antibiotics with negative blood cultures at 48-96 hours at ten U.S. hospitals during September 2018-May 2020. A 23-item safety check excluded patients with ongoing signs of infection, concerning or inadequate microbiologic data, or high-risk conditions (Figure 1). Eligible patients were randomized to the opt-out protocol vs. usual care. The primary outcome was 30-day post-enrollment antibacterial days of therapy (DOT). Clinicians caring for intervention patients were contacted by a pharmacist or physician to encourage antibiotic discontinuation or de-escalation using opt-out language, discuss rationale for continuing antibiotics, working diagnosis, and de-escalation and duration plans. Hurdle models separately compared the odds of antibiotic continuation and DOT distributions among those who continued antibiotics.

Components of the De-Escalating Empiric Therapy: Opting-OUt of Rx in Selected patients with Suspected Sepsis (DETOURS) Trial Protocol

Results

Among 9606 screened, 767 (8%) were enrolled (Figure 2). Common reasons for exclusion were antibiotics given prior to blood culture (35%), positive culture from non-blood sites (26%), and increased oxygen requirement (21%). Intervention patients had 32% lower odds of antibiotic continuation (79% vs. 84%, OR 0.68, 95% confidence interval [0.47, 0.98]). DOT distributions among those who continued antibiotics were similar (ratio of means 1.06 [0.88-1.26], Figure 3). Fewer intervention patients were exposed to extended-spectrum agents (38% vs. 44%). Common reasons for continuing antibiotics were treatment of localized infection (76%) and belief that stopping antibiotics was not safe (31%). Safety outcomes such as mortality, readmission, sepsis relapse, C. difficile, and length of stay did not differ.

DETOURS Trial Flow Diagram

Flow of participants through the DETOURS Trial.

Observed Days of Antibiotic Therapy Among Intervention and Control Subjects in the DETOURS Trial

Post-enrollment days of antibiotic therapy among 767 DETOURS Trial participants in 10 US acute care hospitals within 30 days after enrollment. Dark pink color indicates percent overlap between intervention (purple) and control (light pink) groups.

Conclusion

In this patient-level randomized trial of a stewardship intervention, the opt-out de-escalation protocol targeting selected patients with suspected sepsis resulted in more antibiotic discontinuations but did not affect safety events.

Disclosures

Rebekah W. Moehring, MD, MPH, UpToDate, Inc. (Other Financial or Material Support, Author Royalties) Michael Z. David, MD PhD, GSK (Board Member) Michael Klompas, MD, MPH, UpToDate (Other Financial or Material Support, Chapter Author)

1413. Effect of Automated Identification of Antimicrobial Stewardship Opportunities for Urinary Tract Infections

Background

The treatment of asymptomatic bacteriuria (ASB) does not improve clinical outcomes in most patients and may be associated with an increased risk of adverse events such as Clostridioides difficile infection. A best practice alert (BPA) was created to identify patients with possible ASB for antimicrobial stewardship (AS) review. We aimed to determine whether automated identification of ASB improved the timing of stewardship intervention.

Methods

An electronic health record BPA message to inpatient AS pharmacists was activated on 01/19/2021. The BPA identified inpatients with a new antibiotic order with an associated genitourinary indication and a preceding urinalysis with 0 to 5 WBC/hpf. BPAs were reviewed by an AS pharmacist during weekdays and normal business hours. We retrospectively evaluated the impact of the BPA on time from order to stewardship intervention between a cohort of pre-BPA (01/2020 to 12/2020) and post-BPA (01/20/2021 to 04/10/2021) patients. Included patients met the BPA criteria and had an AS intervention within 7 days of the antibiotic order. We specified interventions that were UTI-related. The median time from antibiotic order entry to any AS intervention was compared pre- to post-BPA using the Mann Whitney U test. Rates of UTI-related interventions were compared with Fisher’s Exact test.

Results

327 antibiotic orders met BPA criteria and were analyzed: 245 and 82 in the pre- and post-BPA group, respectively. Groups had similar baseline characteristics (Table 1). A total of 33 (27 UTI-related) pre-BPA group and 24 (17 UTI-related) post-BPA group interventions were documented by the AS team. The median time to any intervention was 28 hours (IQR 18-64.5) in the pre-BPA group compared to 13.5 hours (IQR 3.5-28.75) in the post-BPA group (p = 0.03, Figure). The pre-BPA group had a lower rate of UTI-related interventions compared to the post-BPA group (11.0% vs 20.7%, p = .04).

Conclusion

Automated identification of antibiotics targeting UTI with urinalysis showing absence of pyuria reduced the time to stewardship intervention and increased rate of UTI-specific interventions. The use of clinical decision support may aid in efficiency of AS review and syndrome-targeted AS impact.

Disclosures

Rebekah W. Moehring, MD, MPH, UpToDate, Inc. (Other Financial or Material Support, Author Royalties)

51. Development and Assessment of a Process to Describe the Timing of Antibiotic Changes in Adult Inpatients

Background

Hospital antimicrobial stewardship programs (ASP) perform prospective audit and feedback to optimize use of antimicrobials; however, workflow inefficiency continues to be a distinct challenge. We developed a method to describe the volume and timing of antimicrobial changes to inform decisions on optimal timing of ASP review and intervention.

Methods

This retrospective study was performed at Duke University Hospital using anonymized antibiotic administration records from the DASON central database. Eligible antibiotic courses were administered to inpatients ≥ 18 years of age and had received ≥ 2 antibiotics administrations for ≥ 24 hours of treatment. A 2-month exploratory cohort (September to October 2017) was used to develop an antibiotic spectrum ranking (Table 1) and decision algorithm which was applied to a 1-year cohort (November 2017 to October 2018) for analysis of total change in antibiotic orders by day of the week. For each interval, the sum of antibiotic ranks was calculated and applied using specified definitions (Table 2) to determine the type of change occurring. The primary outcome was the number of total antibiotic changes that occurred on each day of the week. Secondary outcomes included the number and type (initiations, discontinuations, de-escalations, and escalations) of change. Descriptive statistics were used to describe the outcomes by day of the week.

Table 1: Antibiotic Spectrum Ranking

Table 2: Key Definitions

Results

The ranking and decision algorithm were applied to 16,993 unique antibiotic courses. Total changes occurred most on Wednesday (14,971, 16.2% [95% CI 15.7–17.1%]) and Friday (14,349, 15.6% [95% CI 15.0–16.2%]). Compared to intervals on weekdays (0.407 mean changes per patients on antibiotics [95% CI 0.401–0.413]), weekends had a lower number of changes (0.363 mean changes per patients on antibiotics [95% CI 0.349–0.377]). Initiations occurred most frequently on Tuesday (3,078, 18.1% [95% CI 16.3–19.9%]), and discontinuations on Wednesday (3,179, 18.7% [95% CI 17.4–20.5%]) (Figure 1).

Figure 1: Types of Changes per Day

Conclusion

We developed and applied a method to characterize antimicrobial changes. In our institution, the reductions in the number of changes observed on weekends provide an opportunity for ASP involvement to be incorporated and help facilitate appropriate antimicrobial changes.

Disclosures

Rebekah W. Moehring, MD, MPH, Agency for Healthcare Quality and Research (Grant/Research Support)Centers for Disease Control and Prevention (Grant/Research Support)

1303. Characterization of Isavuconazole Serum Concentrations with Various Administration Routes in a Hospitalized Cohort

Background

Patients with invasive fungal infections are often critically ill and immunosuppressed with multiple comorbidities that may impact drug absorption and exposure. This study sought to characterize isavuconazole serum concentrations (ISCs) in a cohort of real-world hospitalized patients when administered by intravenous solution (IV), enteral as intact capsules, or tube as opened capsule contents.

Methods

This retrospective cohort analysis included all hospitalized patients who received isavuconazole as prophylaxis or treatment between September 2017 and September 2018 and had therapeutic drug monitoring performed. For patients receiving isavuconazole by tube, the capsules were opened and contents were diluted with 10-30 mL of sterile water. Administration was per package insert for intact capsules and IV solution. ISCs were obtained as part of routine care and were quantified by high-performance liquid chromatography. An appropriate trough was defined as within 4 hours of the next scheduled dose. Currently, there is a lack of correlation between isavuconazole exposure and efficacy or toxicity; thus, ISCs were compared between administration routes.

Results

93 ISCs were obtained during 65 encounters from 55 unique patients. The majority of patients were post-transplant (69.1%) and death occurred during 12 (18.5%) encounters. ISCs based on different characteristics of the cohort are shown in Table 1. All ISC assessments were detectable, median 2.3 mg/dL (Q1: 1.5 mg/dL, Q3: 3.3 mg/dL). Administration via tube achieved similar ISCs compared with IV therapy (1.6 mg/dL vs. 1.9 mg/dL, respectively). However, administration of intact capsules resulted in higher median ISCs, 3 mg/dL (Q1: 1.9 mg/dL, Q3: 4.1 mg/dL). All 14 patients with administration via tube were post-transplant, which was not shown to have a significant impact on ISCs (median, transplant 2.2 mg/dL vs. non-transplant 2.7 mg/dL).

Table 1. Characterization of Isavuconazole Concentrations

Conclusion

ISCs were detectable in all patients regardless of transplant status or location at the time of assessment. Administration of isavuconazole via an enteral feeding tube achieved comparable serum concentrations compared with FDA-approved routes of administration and may represent an important alternative for select patients.

Disclosures

All Authors: No reported disclosures

224. Effect of Easing Overnight Restrictions on Antimicrobial Starts

Background

Some institutions allow administration of restricted antibiotics overnight until evaluation the following day (i.e. first dose free) to adapt to limitations in personnel resources. Whether this method results in higher number of overnight requests compared to strict 24/7 preauthorization has not been fully described.

Methods

In October 2019, Duke University Hospital (DUH) changed from strict preauthorization to allow initiation of two restricted agents (meropenem and micafungin) between the hours of 11pm to 7am. We performed an interrupted time series (ITS) analysis to evaluate the phase shift and change in trend in the number of new meropenem and micafungin orders per week before (Jan 2019-Oct 2019) and after (Oct 2019- Mar 2020) the process change. First antimicrobial orders for meropenem and micafungin were counted for unique patient encounters. We fit a Gaussian distribution function to the number of orders per hour of day to estimate the percent of orders initiated overnight (11p-7a) and during day/evening hours (7a-11p) before and after the process change.

Results

Hospital data included 1728 new meropenem and micafungin orders over a 61-week period (~28 per week). The total number of meropenem and micafungin orders was constant between Jan 2019 and October 2019 (+0.07 orders/week, 95% CI -0.13 to 0.27, Figure 1) and the phase shift during the first week of October was non-significant (-4.38 orders, 95% CI -12.34 to 3.58). The number of orders increased after October 2019 (+0.70 orders/week, 95% CI 0.13 to 1.25), however a sensitivity analysis removing the largest outlier eliminates significance. The percent of total orders between 11am to 7pm increased from 13.3% to 17.2% after the intervention (Figure 2). Overall antibiotic use remained similar through the study period.

Figure 1. Estimated Approvals per Week

Figure 2. Approvals by Hour of Day

Conclusion

There was no significant immediate change in overnight prescribing of meropenem and micafungin, however a trend towards increased number of orders appeared after removing overnight restriction requirements. Instead of “stealth dosing”, where providers wait to enter restricted antibiotic orders until evening hours, we observed a small increase in starts in early morning hours (1am-6am). Preauthorization approaches must adapt to personnel resources and quality of life for antimicrobial stewards.

Disclosures

Michael J. Smith, MD, MSC.E, Kentucky Medicaid (Grant/Research Support)Merck (Grant/Research Support) Rebekah W. Moehring, MD, MPH, Agency for Healthcare Quality and Research (Grant/Research Support)Centers for Disease Control and Prevention (Grant/Research Support)

203. Opportunities for Antimicrobial Stewardship in Febrile Neutropenia

Background

Emerging evidence suggests antibiotics may be safely discontinued before neutropenia resolves in patients without identifiable infection. We estimated the volume of encounters and antibiotic use for future stewardship interventions shortening FN treatment duration.

Methods

This retrospective cohort study used electronic health records from inpatient encounters on the hematologic malignancies ward at Duke University Hospital from 5/21/2018 to 12/31/2019 where patients received at least one antibiotic for an indication of “neutropenic fever.” The primary outcome was length of therapy (LOT) of broad Gram-negative (GN) agents, including cefepime, piperacillin-tazobactam, meropenem, or aztreonam. FN LOT was counted by calendar day, starting with the first day of administration of a broad GN agent and ending with antibiotic discontinuation or hospital discharge. Encounters with at least one positive blood culture (positive cohort) were compared to those with no positive blood cultures (negative cohort) to assess if culture positivity was associated with differences in FN LOT. We included the first FN LOT from each encounter in the negative cohort and the FN LOT associated with the first positive blood culture in the positive cohort. We used descriptive statistics and a Gaussian density function to calculate the percent of encounters exceeding FN LOT of 14 days and the percent of broad GN agent days.

Results

We evaluated 15,678 GN antibiotic administrations from 471 unique FN encounters. Blood culture results were available for 443 encounters— 122 (27.5%) in the positive cohort, and 321 (72.5%) encounters in the negative cohort. Thirty percent of encounters (36/122) in the positive cohort received more than one GN treatment course, compared to 10% (32/321) of those in the negative cohort. FN LOT was significantly longer in the positive cohort (median 10.5, IQR 13 days vs. 6, IQR 8 days, p < 0.001). Among encounters with negative cultures, 57 (17.8%) had a first FN LOT greater than 14 days, accounting for 44% of broad GN agent days within that population (Figure 1).

Gram-Negative Antibiotic Therapy in Blood Culture-Negative Febrile Neutropenia

Conclusion

Nearly 20% of blood culture-negative encounters received initial GN treatment courses exceeding 14 days, representing a sizeable target for antimicrobial stewardship interventions focused on FN treatment duration.

Disclosures

Rebekah W. Moehring, MD, MPH, Agency for Healthcare Quality and Research (Grant/Research Support)Centers for Disease Control and Prevention (Grant/Research Support)

Characterization of Isavuconazole serum concentrations after enteral feeding tube administration in a hospitalized cohort: A case series

WHAT IS KNOWN AND OBJECTIVE

Invasive fungal infections often occur in patients with comorbidities that complicate oral administration. Serum concentrations of isavuconazole were characterized after enteral tube administration.

CASE DESCRIPTION

Thirteen of 14 isavuconazole concentrations were >1 mg/dl (median 1.6 mg/dl) among those receiving enteral tube administration, which was comparable to intravenous (median 1.9 mg/dl). Higher concentrations were observed during oral administration (median 3 mg/dl).

WHAT IS NEW AND CONCLUSION

Administration of isavuconazole via tube resulted in concentrations comparable to FDA-approved routes of administration. This route may be feasible and appropriate for select patients.

Ceftolozane-tazobactam: A new-generation cephalosporin

PURPOSE

The chemistry, pharmacokinetic and pharmacodynamic properties, efficacy, and safety of the recently introduced combination antimicrobial agent ceftolozane-tazobactam are reviewed.

SUMMARY

Ceftolozane-tazobactam (Zerbaxa, Cubist Pharmaceuticals) is a cephalosporin β-lactam and β-lactamase inhibitor marketed as a fixed-dose combination agent for the treatment of complicated urinary tract and intraabdominal infections. Its dosing and chemistry provide expansive antimicrobial coverage of gram-negative organisms, including Pseudomonas aeruginosa, and stable activity against many β-lactamases, as well as coverage of most extended-spectrum β-lactamase-producing organisms and some anaerobes. Ceftolozane-tazobactam is susceptible to hydrolysis by carbapenemase enzymes but is not affected by other resistance mechanisms such as efflux pumps and porin loss. Clinical trials demonstrated that combination treatment with ceftolozane-tazobactam plus metronidazole had efficacy comparable to that of levofloxacin in patients with complicated urinary tract infections, including pyelonephritis, and comparable to that of meropenem against complicated intraabdominal infections. A Phase III trial of ceftolozane-tazobactam versus meropenem for treatment of bacterial pneumonia, including ventilator-associated pneumonia, is underway. Adverse effects reported with ceftolozane-tazobactam use are comparable to those seen with other β-lactams (e.g., hypersensitivity, nausea, diarrhea, headache). Initially, ceftolozane-tazobactam may be reserved for targeted therapy against multidrug-resistant pathogens.

CONCLUSION

Ceftolozane-tazobactam is a new cephalosporin with enhanced activity against multidrug-resistant P. aeruginosa and other gram-negative pathogens.

Bullous pemphigoid: corticosteroid treatment and adverse effects in long-term care patients

Bullous pemphigoid (BP) is the most common autoimmune bullous disease. It primarily presents in elderly patients older than 70 years of age. The presentation can vary with localized or generalized disease that variably affects mucosal tissue. Therapy primarily consists of administration of topical and systemic corticosteroids. Topical corticosteroids are effective with less adverse effects compared with systemic steroids. Other therapies, such as steroid-sparing agents and plasma exchanges, have been recommended and studied to some degree, but these require more evidence before they can be routinely recommended. A 68-year-old African-American female resident of a nursing facility develops a rash and is evaluated at a dermatology clinic. Since the resident has many medications and concomitant diseases, the physician at first suspected a drug rash. On subsequent visits, the resident undergoes multiple punch biopsies and is diagnosed with BP. Treatment is initiated with topical steroids, systemic steroids, and oral minocycline. On a follow-up visit, the resident is showing improvement of her BP. However, the resident's hypertension and hyperglycemia are now uncontrolled as a result of the discontinuation of hydrochlorothiazide and the initiation of steroid therapy. This case highlights the dangers of corticosteroids in patients, especially the elderly, who have multiple comorbidities.

Avoidable causes of cancellation in elective orthopaedic surgery

As part of an audit of clinical practice in an orthopaedic unit for elective surgery, a study was made of the causes of cancellation of operations. Despite careful liaison with general practitioners, and a booked admission policy, over 6% of patients were cancelled as unsuitable. The results of this study suggest that the number of cancellations on medical grounds would be reduced by closer liaison with general practitioners, and the establishment of preadmission clinics. Ensuring that only consultants book patients for surgery would also reduce the number of cancellations due to incorrect indications for surgery.

A prospective study of lumbar spinal movements before and after discectomy using biplanar radiography. Correlation of clinical and radiographic findings

The significance of alteration of lumbar spinal motion in cases of herniated disc was examined using a three-dimensional x-ray technique (biplanar radiography) before and 3 months after discectomy. Fifteen consecutive cases of disc herniation were studied prospectively. Predictions of clinical examination, myelography, and motion study for the level and site of the lesion were correlated with the operative findings for their accuracy in localization of the lesion. Changes in lumbar spinal motion after surgery were also correlated with the clinical results. The clinical and myelographic predictions were similar to previously published studies. The present study showed that patients with a sequestrated or prolapsed disc lesion (as opposed to bulging disc) had an abnormally large lateral bend or axial rotation during flexion and extension at the level above, which reduced after surgery. Primary lumbar spinal motions (flexion and extension) were generally reduced to half of the normal value and were not significantly altered by surgery. The restriction of lumbar spinal motion was not significantly reflected in the clinical results, which were satisfactory in most cases. Discectomy by fenestration and minimal resection of the lamina did not produce instability.

Familial osteochondritis dissecans and dwarfism

We review four generations of a short statured family in whom 12 members have osteochondritis dissecans (O.D.) affecting the knees, elbow, or both, and other minor anomalies of bony development are recorded. Four of the family, unaffected by O.D., exhibit idiopathic scoliosis.

The effect of environmental temperature and nutritional intake on the metabolic response to abdominal surgery

Ambient temperatures of 29°C. had no effect on the nitrogen balance after elective abdominal surgery in 15 well-nourished men compared with 29 similar patients nursed at 24°C. The catabolic response as measured by nitrogen balance is small following operation of moderate severity and can be abolished by an increased intake of nitrogen and calories.