A Constitutive EGFR Kinase Dimer to Study Inhibitor Pharmacology.

Lung cancer is commonly caused by activating mutations in the epidermal growth factor receptor (EGFR). Allosteric kinase inhibitors are unaffected by common ATP-site resistance mutations and represent a promising therapeutic strategy for targeting drug-resistant EGFR variants. However, allosteric inhibitors are antagonized by kinase dimerization, and understanding this phenomenon has been limited to cellular experiments. To facilitate the study of allosteric inhibitor pharmacology, we designed and purified a constitutive EGFR kinase dimer harboring the clinically relevant L858R/T790M mutations. Kinetic characterization revealed that the EGFR kinase dimer is more active than monomeric EGFR(L858R/T790M) kinase and has the same Km,ATP Biochemical profiling of a large panel of ATP-competitive and allosteric EGFR inhibitors showed that allosteric inhibitor potency decreased by >500-fold in the kinase dimer compared with monomer, yielding IC50 values that correlate well with Ba/F3 cellular potencies. Thus, this readily purifiable constitutive asymmetric EGFR kinase dimer represents an attractive tool for biochemical evaluation of EGFR inhibitor pharmacology, in particular for allosteric inhibitors. SIGNIFICANCE STATEMENT: Drugs targeting epidermal growth factor receptor (EGFR) kinase are commonly used to treat lung cancers but are affected by receptor dimerization. Here, we describe a locked kinase dimer that can be used to study EGFR inhibitor pharmacology.

Tuning micelle dimensions and properties with binary surfactant mixtures.

Detergent micelles are used in many areas of research and technology, in particular, as mimics of the cellular membranes in the purification and biochemical and structural characterization of membrane proteins. Applications of detergent micelles are often hindered by the limited set of properties of commercially available detergents. Mixtures of micelle-forming detergents provide a means to systematically obtain additional micellar properties and expand the repertoire of micelle features available; however, our understanding of the properties of detergent mixtures is still limited. In this study, the shape and size of binary mixtures of seven different detergents commonly used in molecular host-guest systems and membrane protein research were investigated. The data suggests that the detergents form ideally mixed micelles with sizes and shapes different from those of pure individual micelles. For most measurements of size, the mixtures varied linearly with detergent mole fraction and therefore can be calculated from the values of the pure detergents. We propose that properties such as the geometry, size, and surface charge can be systematically and predictably tuned for specific applications.

The Effect of Retained Hardware on Failure Among Prosthetic Joint Infections of the Knee in the Presence and Absence of Staphylococcus aureus.

Background: The risk of failure associated with different surgical strategies for prosthetic joint infections (PJIs) among patients with and without Staphylococcus aureus is uncertain. The purpose of this study was to assess whether S. aureus modifies the association between retained hardware and failure following revision surgery for PJI of the knee. Methods: This was a single-center retrospective cohort study of 106 first PJIs of the knee between 2016 and 2020 at a rural academic medical center. The exposure was retained hardware following revision surgery for PJI, and the outcomes were recurrent infection, any infection, and a composite outcome including any infection, unplanned revision, failure to undergo reimplantation, amputation, or death within 2 years of revision. We used negative binomial regression to quantify the association between the exposure and outcome and to assess the presence of S. aureus as an effect modifier. Results: Retained hardware was significantly associated with failure when defined as recurrent infection among S. aureus PJI (adjusted risk difference [aRD], 0.38; 95% CI, 0.12-0.64) but not in the absence of S. aureus (aRD, -0.02; 95% CI, -0.17 to 0.13), and S. aureus was an effect modifier (P interaction = .01). Conclusions: We report a significant association between the presence of retained hardware and recurrent infection among S. aureus PJI of the knee, but not for non-S. aureus PJI. This could help inform the surgical management of PJI of the knee in cases where the microbiology is known before surgery.

Effectiveness of immunoglobulin replacement therapy in preventing infections in patients with chronic obstructive pulmonary disease: a systematic review.

PURPOSE: Immunoglobulin replacement therapy is a standard treatment for patients with antibody production deficiencies, which is of interest in patients with chronic obstructive pulmonary disease (COPD). This systematic review, registered with PROSPERO (CRD42021281118), assessed the current literature regarding immunoglobulin replacement therapy on COPD clinical outcomes in patients with low immunoglobulin G (IgG) serum concentrations. METHODS: Literature searches conducted from inception to August 23, 2021, in databases including MEDLINE, EMBASE, and CINAHL. Population (sex, age, comorbidities), baseline clinical characteristics (pulmonary function testing results, IgG levels), and outcome (hospitalizations, emergency department visits) were extracted after title/abstract and full text screening. The Cochrane risk of bias assessment form was used for risk of bias assessment of randomized controlled trials and the National Heart, Lung, and Blood Institute (NHLBI) assessment was used for pre and post studies. RESULTS: A total of 1381 studies were identified in the preliminary search, and 874 records were screened after duplicates were removed. Screening 77 full texts yielded four studies that were included in the review. CONCLUSION: It is unclear whether immune globulin replacement therapy reduces acute exacerbation frequency and severity in COPD. Current evidence suggests that it is worth considering, but better developed protocols for administration of immune globulin supplementation is required for future randomized controlled trials.

Novel BRD2::NUTM1 Fusion in NUT Carcinoma With Exceptional Response to Chemotherapy: A Case Report.

We present the first known case of a patient with BRD2::NUTM1-driven NUT carcinoma. A 59-year-old woman presented with poorly differentiated squamous cell lung cancer metastatic to the pleura. Eventually, a positive NUT immunohistochemistry, NUT fluorescence in situ hybridization, and RNA next-generation sequencing with a BRD2::NUTM1 fusion led to the diagnosis of NUT carcinoma. She received multiple lines of chemotherapy with response and is still alive at 2 years postdiagnosis. This report expands on the known fusions in NUT carcinoma and highlights potential differences in patient prognosis on the basis of gene fusion partners.

National survey study of nirmatrelvir-ritonavir prescribing processes and access barriers during the severe acute respiratory coronavirus virus 2 (SARS-CoV-2) omicron surge of the coronavirus disease 2019 (COVID-19) pandemic.

In this national survey, we found that individual patient assessments by pharmacists were more common at facilities using centralized prescribing for nirmetralvir-ritonavir (Paxlovid) than decentralized prescribing. Provider discomfort was initially less with centralized prescribing, but later, there was no difference in provider discomfort based on prescribing mechanism.

A survey study of the association between active utilization of National Healthcare Safety Network resources and central-line-associated bloodstream infection reporting.

In this survey of 41 hospitals, 18 (72%) of 25 respondents reporting utilization of National Healthcare Safety Network resources demonstrated accurate central-line-associated bloodstream infection reporting compared to 6 (38%) of 16 without utilization (adjusted odds ratio, 5.37; 95% confidence interval, 1.16-24.8). Adherence to standard definitions is essential for consistent reporting across healthcare facilities.

A comparison of National Healthcare Safety Network surveillance definitions to physician review for central-line-associated bloodstream infections.

For 147 hospital-onset bloodstream infections, we assessed the sensitivity, specificity, positive predictive value, and negative predictive value of the National Healthcare Safety Network surveillance definitions of central-line-associated bloodstream infections against the gold standard of physician review, examining the drivers of discrepancies and related implications for reporting and infection prevention.

Association between in situ steroids and spine surgical site infections among instrumented procedures.

OBJECTIVE: To estimate the association between in situ steroids and spine surgical-site infections (SSIs), assessing spinal instrumentation as an effect modifier and adjusting for confounders. DESIGN: Case-control study. SETTING: Rural academic medical center. PARTICIPANTS: We identified 1,058 adults undergoing posterior fusion and laminectomy procedures as defined by the National Healthcare Safety Network without a pre-existing SSI between January 2020 and December 2021. We identified 26 SSI as cases and randomly selected 104 controls from the remaining patients without SSI. METHODS: The primary exposure was the intraoperative administration of methylprednisolone in situ (ie, either in the wound bed or as an epidural injection). The primary outcome was a clinical diagnosis of SSI within 6 months of a patient's first spine surgery at our facility. We quantified the association between the exposure and outcome using logistic regression, using a product term to assess for effect modification by spinal instrumentation and the change-in-estimate approach to select significant confounders. RESULTS: Adjusting for Charlson comorbidity index and malignancy, in situ steroids were significantly associated with spine SSI relative to no in situ steroids for instrumented procedures (adjusted odds ratio [aOR], 9.93; 95% confidence interval [CI], 1.54-64.0), but they were not associated with spine SSIs among noninstrumented procedures (aOR, 0.86; 95% CI, 0.15-4.93). CONCLUSIONS: In situ steroids were significantly associated with spine SSI among instrumented procedures. The benefits of in situ steroids for pain management following spine surgery should be weighed against the risk of SSI, especially for instrumented procedures.

Investigating potential drivers of increased central line...associated bloodstream infections during the coronavirus disease 2019 (COVID-19) Omicron surge.

Central line...associated bloodstream infection rates increased during the Omicron surge at our rural academic medical center. To identify potential drivers of this increase, we investigated period- and patient-specific factors associated with the increase in central line...associated bloodstream infection. Increased central line utilization, decreased central line bundle compliance monitoring, increased proportion of traveling nurses, increased short-term venous catheter use in the internal jugular vein, increased multilumen catheter use, decreased port...associated infection, and increased patient acuity were significantly associated with the surge. Our results helped us target our local infection prevention efforts.

Association Between Foot Surgery Type and Subsequent Healing in Veterans With Moderate-to-Severe Diabetic Foot Infections.

BACKGROUND: Diabetic foot infections are a common precursor to lower extremity amputations. The treatment of diabetic foot infections involves both medical and surgical management, of which limb-sparing surgeries are increasingly preferred over amputations at or above the ankle to preserve mobility and quality of life. The outcomes following these limb-sparing surgeries are not well described. METHODS: This was a single-center, retrospective cohort study of 90 Veterans with moderate-to-severe diabetic foot infections between 2017 and 2019 from the Veterans Affairs Maryland Health Care System. The exposure was foot surgery with bone resection (ie, toe amputation, metatarsal resection, transmetatarsal amputation) vs debridement alone. The outcome was healing within 1 year. We used log-binomial regression to assess the association between foot surgery type and healing, stratify by infection location, and evaluate potential confounding variables. RESULTS: The cumulative incidence of healing after foot surgery with bone resection was greater than that following debridement (risk ratio [RR], 1.80 [95% confidence interval {CI}, 1.17-2.77]). This association was modified by infection location and greater for toe infections (RR, 4.52 [95% CI, 1.30-15.7]) than other foot infections (RR, 1.19 [95% CI, .69-2.02]). We found no evidence of confounding by comorbidities or infection severity. CONCLUSIONS: For patients with toe infections, foot surgery with bone resection was associated with better healing than debridement alone. The multiple specialties caring for patients with diabetic foot infections need a stronger common knowledge base-from studies like this and future studies-to better counsel patients about their treatment and prognosis.

Reliability and accuracy of a method for measuring temporomandibular joint condylar volume.

OBJECTIVE: The aim of this study was to develop and validate a technique for mandibular condyle segmentation and volume determination by using cone beam computed tomography (CBCT). STUDY DESIGN: A dry skull was used to generate 3 dimensional (3-D)-printed mandible models that were then imaged by using CBCT. Semiautomatic segmentation of condyles was completed. The Frankfurt plane was established and translated to the most inferior point of the sigmoid notch, and the condylar volume superior to the plane was determined. This procedure was repeated on 3-D-printed mandibles by using physical landmarks and the water displacement method to obtain the physical volume. This was repeated 3 times to evaluate reliability. Sensitivity analysis was performed to demonstrate the effect of discrepancies in locating landmarks in the Frankfurt plane. Condylar volume measurements obtained from CBCT were compared with physical measurements through repeated-measures analysis of variance (ANOVA) to determine accuracy. RESULTS: Condylar volume obtained from CBCT and physical measurements resulted in an intraclass correlation coefficient of 0.988 (0.918, 0.998) (P < .01) with both modalities, demonstrating excellent intrarater reliability. The mean difference of volume measurements between the modalities was not statistically significant (P = .365). Potential discrepancies in porion coordinates had minimal impact on condylar volume change. CONCLUSIONS: The condylar segmentation technique proved to be a reliable and accurate method for evaluating condylar volume.

Multicenter retrospective cohort study of the clinical significance of Staphylococcus lugdunensis isolated from a single blood culture set.

BACKGROUND: Staphylococcus lugdunensis is a coagulase negative Staphylococcus species and frequent human skin commensal with the potential for aggressive infection. Guidance surrounding S. lugdunensis bacteremia (SLB) from a single set of blood cultures is lacking. METHODS: A multicenter, retrospective cohort of patients with SLB from at least one blood culture set within the University of Maryland Medical System from 2015 to 2019 is presented. Objectives are to describe baseline characteristics, compare the clinical status and treatment course, and to evaluate the clinical outcomes among patients with SLB in single versus multiple sets. RESULTS: Thirty-six patients were included, 24 with one set of blood cultures positive for S lugdunensis and 12 with multiple sets. Baseline characteristics were similar between the groups, though patients with SLB in multiple sets were more commonly on hemodialysis (P = 0.029). Central lines were the most common source (17%). Most (97%) fulfilled systemic inflammatory response syndrome or Souvenir criteria, had an infectious focus on imaging, or had a second positive culture site. Most (78%) were treated as clinically significant. Patients with multiple positive sets were more commonly treated with antibiotics for >2 weeks (P = 0.02). CONCLUSIONS: SLB was rare and occurred more frequently as a single set of positive cultures. Patient characteristics and clinical courses were similar between single and multiple set groups. Given the potential severity of S. lugdunensis bacteremia it seems prudent to treat S. lugdunensis in a single blood culture as true bacteremia, pending larger studies and guidelines.

Short-Stay Admissions Associated With Large COVID-19 Outbreaks in Maryland Nursing Homes.

At the beginning of the COVID-19 pandemic, some nursing homes (NHs) in Maryland suffered larger outbreaks than others. This study examined how facility characteristics influenced outbreak size. We conducted a retrospective analysis of secondary data from Maryland NHs to identify characteristics associated with large outbreaks, defined as when total resident cases exceeded 10% of licensed beds, from January 1, 2020, through July 1, 2020. Our dataset was unique in its inclusion of short-stay residents as a measure of resident type and family satisfaction as a measure of quality. Facility characteristics were collected prior to 2020. Like other studies, we found that large outbreaks were more likely to occur in counties with high cumulative incidence of COVID-19, and in NHs with more licensed beds or fewer daily certified nursing assistant (CNA) hours. We also found that NHs with a greater proportion of short-stay residents were more likely to have large outbreaks, even after adjustment for other facility characteristics. Lower family satisfaction was not significantly associated with large outbreaks after adjusting for CNA hours. Understanding the characteristics of NHs with large COVID-19 outbreaks can guide facility re-structuring to prevent the spread of respiratory infections in future pandemics.

Diabetic Foot Infections: Local Prevalence of and Case-Control Study of Risk Factors for Methicillin-Resistant Staphylococcus aureus and Pseudomonas aeruginosa.

We identified deep diabetic foot infections by culture and conducted a case-control study examining the risk factors for moderate to severe methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PsA) diabetic foot infections. Our MRSA prevalence was lower than literature values; PsA was higher. Gangrene may be predictive of Pseudomonas infection.

Burden of perianal Staphylococcus aureus colonization in nursing home residents increases transmission to healthcare worker gowns and gloves.

OBJECTIVE: To evaluate the effect of the burden of Staphylococcus aureus colonization of nursing home residents on the risk of S. aureus transmission to healthcare worker (HCW) gowns and gloves. DESIGN: Multicenter prospective cohort study. SETTING AND PARTICIPANTS: Residents and HCWs from 13 community-based nursing homes in Maryland and Michigan. METHODS: Residents were cultured for S. aureus at the anterior nares and perianal skin. The S. aureus burden was estimated by quantitative polymerase chain reaction detecting the nuc gene. HCWs wore gowns and gloves during usual care activities; gowns and gloves were swabbed and then cultured for the presence of S. aureus. RESULTS: In total, 403 residents were enrolled; 169 were colonized with methicillin-resistant S. aureus (MRSA) or methicillin-sensitive S. aureus (MSSA) and comprised the study population; 232 were not colonized and thus were excluded from this analysis; and 2 were withdrawn prior to being swabbed. After multivariable analysis, perianal colonization with S. aureus conferred the greatest odds for transmission to HCW gowns and gloves, and the odds increased with increasing burden of colonization: adjusted odds ratio (aOR), 2.1 (95% CI, 1.3-3.5) for low-level colonization and aOR 5.2 (95% CI, 3.1-8.7) for high level colonization. CONCLUSIONS: Among nursing home patients colonized with S. aureus, the risk of transmission to HCW gowns and gloves was greater from those colonized with greater quantities of S. aureus on the perianal skin. Our findings inform future infection control practices for both MRSA and MSSA in nursing homes.