Comparison of Omicron breakthrough infection versus monovalent SARS-CoV-2 intramuscular booster reveals differences in mucosal and systemic humoral immunity.

Our understanding of the quality of cellular and humoral immunity conferred by COVID-19 vaccination alone versus vaccination plus SARS-CoV-2 breakthrough (BT) infection remains incomplete. While the current (2023) SARS-CoV-2 immune landscape of Canadians is complex, in late 2021 most Canadians had either just received a third dose of COVID-19 vaccine, or had received their two-dose primary series and then experienced an Omicron BT. Herein we took advantage of this coincident timing to contrast cellular and humoral immunity conferred by three doses of vaccine versus two doses plus BT. Our results show thatBT infection induces cell-mediated immune responses to variants comparable to an intramuscular vaccine booster dose. In contrast, BT subjects had higher salivary immunoglobulin (Ig)G and IgA levels against the Omicron spike and enhanced reactivity to the ancestral spike for the IgA isotype, which also reacted with SARS-CoV-1. Serumneutralizing antibody levels against the ancestral strain and the variants were also higher after BT infection. Our results support the need for the development of intranasal vaccines that could emulate the enhanced mucosal and humoral immunity induced by Omicron BT without exposing individuals to the risks associated with SARS-CoV-2 infection.

Career Outcomes of Nondesignated Preliminary Surgery Residents: A Systematic Review and Meta-Analysis.

OBJECTIVE: Nondesignated preliminary surgery (NDPS) residency offers postgraduate medical education with no guarantee of a subsequent categorical position. Some literature exists detailing the career outcomes of these residents, but these results are complicated by the limited scale of these studies. The purpose of this systematic review and meta-analysis is to summarize the career outcomes of these residents from the existing literature. METHODS: The PubMed, Scopus, Cochrane, CINAHL, and PsycINFO databases were queried from inception for studies reporting the career outcomes of NDPS residents. Data were collected and extracted by 2 independent reviewers in accordance with PRISMA guidelines. The primary outcome of this study is the proportion of NDPS residents obtaining a categorical general surgery position. Secondary outcomes include the percentages of residents obtaining surgical subspecialty positions, obtaining nonsurgical specialty positions, and leaving graduate medical education. RESULTS: Overall, 13 studies reporting NDPS residents (n = 2606) were identified. The overall pooled estimate for obtaining a categorical general surgery position after NDPS residency was 37.1% (95% CI, 31.3%-43.2%), with significant heterogeneity (I2 = 81.8%; p < 0.001). Residents in the second postgraduate year were significantly more likely than those in the first year to obtain a general surgery position (50.6% vs 29.0%, respectively; p < 0.001). Residents subsequently training in a surgical subspecialty (13.3%) largely entered orthopedics (3.6%), urology (2.1%), and obstetrics and gynecology (1.6%). For residents entering nonsurgical training (32.1%), a majority entered anesthesiology (11.7%), internal medicine (3.8%), and radiology (3.8%). CONCLUSIONS: Although NDPS residents have heterogenous career outcomes, they largely obtain categorical positions in general surgery and surgical subspecialties.

Outcomes of truncal valve replacement in neonates and infants: a meta-analysis.

BACKGROUND: Infants with truncus arteriosus typically undergo repair by repurposing the truncal valve as the neo-aortic valve and using a valved conduit homograft for the neo-pulmonary valve. In cases where the native truncal valve is too insufficient for repair, it is replaced, but this is a rare occurrence with a paucity of data, especially in the infant population. Here, we conduct a meta-analysis to better understand the outcomes of infant truncal valve replacement during the primary repair of truncus arteriosus. METHODS: We systematically reviewed PubMed, Scopus, and CINAHL for all studies reporting infant (<12 months) truncus arteriosus outcomes between 1974 and 2021. Exclusion criteria were studies which did not report truncal valve replacement outcomes separately. Data extracted included valve replacement type, mortality, and reintervention. Our primary outcome was early mortality, and our secondary outcomes were late mortality and reintervention rates. RESULTS: Sixteen studies with 41 infants who underwent truncal valve replacement were included. The truncal valve replacement types were homografts (68.8%), mechanical valves (28.1%), and bioprosthetic valves (3.1%). Overall early mortality was 49.4% (95% CI: 28.4-70.5). The pooled late mortality rate was 15.3%/year (95% CI: 5.8-40.7). The overall rate of truncal valve reintervention was 21.7%/year (95% CI: 8.4-55.7). CONCLUSIONS: Infant truncal valve replacement has poor early and late mortality as well as high rates of reintervention. Truncal valve replacement therefore remains an unsolved problem in congenital cardiac surgery. Innovations in congenital cardiac surgery, such as partial heart transplantation, are required to address this.

Additional Distal Femoral Resection Minimally Improves Terminal Knee Extension: A Systematic Review and Meta-Regression Challenging the Dogma.

Background: Additional distal femoral resection is a common technique to address a flexion contracture during primary total knee arthroplasty (TKA) but can lead to midflexion instability and patella baja. Prior reports regarding the magnitude of knee extension obtained with additional femoral resection have varied. This study sought to systematically review research describing the effect of femoral resection on knee extension and to perform meta-regression to estimate this relationship. Methods: A systematic review was conducted using MEDLINE, PubMed, and Cochrane databases by combining the terms ("flexion contracture" OR "flexion deformity") AND ("knee arthroplasty" OR "knee replacement") to identify 481 abstracts. In total, 7 articles reporting change in knee extension after additional femoral resection or augmentation across 184 knees were included. The mean value for knee extension, its standard deviation, and the number of knees tested were recorded for each level. Meta-regression was performed using weighted mixed-effects linear regression. Results: Meta-regression estimated that each 1mm resected from the joint line produced a 2.5° gain of extension (95% confidence interval, 1.7 to 3.2). Sensitivity analyses excluding outlying observations estimated each 1mm resected from the joint line produced a 2.0° gain of extension (95% confidence interval, 1.9 to 2.2). Conclusions: Each millimeter of additional femoral resection is likely to produce only a 2° improvement in knee extension. Thus, an additional resection of 2 mm is likely to improve knee extension by less than 5°. Alternative techniques, including posterior capsular release and posterior osteophyte resection, should be considered in correcting a flexion contracture during TKA.

Potential for supraphysiologic fluid shear stresses in a rat cemented knee replacement model.

The mechano-biologic environment associated with aseptic loosening of cemented joint replacements is not fully understood. The goal of this study was to use a preclinical rat knee arthroplasty model to explore the changes in cement-bone morphology and micromotion that occur with in vivo service. Narrow gaps between cement and bone under the tibial tray were present at early time points, and with even small magnitude micromotion, resulted in large micromotion-to-gap width ratios. These data were then used to develop models of fluid flow in the cement-bone gaps to estimate potential for high fluid shear stress (FSS). Modeling results revealed supraphysiologic (>4 Pa) FSS were possible, particularly for cases in which eccentric loading applied to the implant and if the fluid in the gap consisted of marrow or synovial fluid. The early, high FSS environment, could cause fluid-induced periprosthetic osteolysis locally, resulting in progressive loss of cement-bone fixation.

Effect of cardiac graft rejection on semilunar valve function: implications for heart valve transplantation.

BACKGROUND: The treatment of neonates with unrepairable heart valve dysfunction remains an unsolved problem because there are no growing heart valve replacements. Heart valve transplantation is a potential approach to deliver growing heart valve replacements. Therefore, we retrospectively analysed the semilunar valve function of orthotopic heart transplants during rejection episodes. METHODS: We included children who underwent orthotopic heart transplantation at our institution and experienced at least one episode of rejection between 1/1/2010 and 1/1/2020. Semilunar valve function was analysed using echocardiography at baseline, during rejection and approximately 3 months after rejection. RESULTS: Included were a total of 31 episodes of rejection. All patients had either no (27) or trivial (4) aortic insufficiency prior to rejection. One patient developed mild aortic insufficiency during a rejection episode (P = 0.73), and all patients had either no (21) or trivial (7) aortic insufficiency at follow-up (P = 0.40). All patients had mild or less pulmonary insufficiency prior to rejection, which did not significantly change during (P = 0.40) or following rejection (P = 0.35). Similarly, compared to maximum pressure gradients across the valves at baseline, which were trivial, there was no appreciable change in the gradient across the aortic valve during (P = 0.50) or following rejection (P = 0.42), nor was there any meaningful change in the gradient across the pulmonary valve during (P = 0.55) or following rejection (P = 0.91). CONCLUSIONS: This study demonstrated that there was no echocardiographic evidence of change in semilunar valve function during episodes of rejection in patient with heart transplants. These findings indicate that heart valve transplants require lower levels of immune suppression than orthotopic heart transplants and provide partial foundational evidence to justify future research that will determine whether heart valve transplantation may deliver growing heart valve replacements for children.

Peripheral Arterial Compression as a New Adjunct Technique to Cardiopulmonary Resuscitation.

The success of cardiopulmonary resuscitation (CPR) is critically dependent on the maintenance of myocardial and cerebral perfusion; therefore, preferential perfusion of these vital organs over non-vital vascular beds, such as the extremities, is desirable. We propose that compression of the femoral and/or brachial arteries during CPR improves resuscitation outcomes.

Risk of recipient age on 1-year mortality after simultaneous heart-lung transplantation.

BACKGROUND: Heart-lung transplantation (HLTx) is relatively uncommon, and there is a paucity of literature to suggest an age at which older recipients may be exposed to excess risk for mortality. This analysis aimed to identify a threshold of age that predicts adverse outcomes after HLTx. METHODS: The United Network of Organ Sharing registry was used to identify adult patients undergoing HLTx from 2005 to 2021. The primary outcome was 1-year mortality. Threshold regression was used to identify the threshold at which age impacts 1-year mortality. Kaplan-Meier analysis was used to model survival, and Cox proportional hazards modeling was used for risk-adjustment. RESULTS: We identified 453 patients undergoing HLTx. Threshold analysis identified that the risk for 1-year mortality was significantly elevated beyond an age of 58 years, and 47 (10.38%) patients were older than this threshold. On Kaplan-Meier analysis, 1-year survival was significantly lower in patients > 58 years compared to younger recipients (64.7% vs. 82.0%, p = .007). After risk adjustment, the hazard ratio for 1-year mortality in recipients older than 58 years was 2.27 (95% confidence interval [1.21-4.28], p = .011). CONCLUSION: A threshold for recipient age of 58 years of age may avoid excess 1-year mortality after HLTx. However, patients older than this threshold demonstrate acceptable early and midterm survival, and the majority survive to 1 year. Advanced age should be considered in patient selection for HLTx, but may not be a contraindication for candidacy particularly in the absence of other risk factors.

Immunosuppressive regimens in porcine transplantation models.

Pigs, or Sus scrofa domestica, are commonly used animal models in translational transplantation research due to their anatomical, physiological, and immunological similarities to humans. In solid organ transplantation studies, immunosuppressive medications may be administered to pigs to prevent rejection. We provide an overview of the immunosuppressive regimens used in allogeneic solid organ transplantation in pigs, including heart, lung, kidney, bowel and cotransplanted organs and focus on the use of tacrolimus, mycophenolate mofetil, and corticosteroids.

Impact of an Extended Telemonitoring and Coaching Program on Continuous Positive Airway Pressure Adherence.

Rationale: The benefits of continuous positive airway pressure (CPAP) therapy in obstructive sleep apnea are limited by adherence. Telemonitoring and coaching have been demonstrated to increase adherence, but the ideal duration of such support is unclear. Objectives: To compare the impact of a 12-month versus a 3-month behavioral support program on CPAP adherence. Methods: We evaluated real-world CPAP adherence data from all patients initiating CPAP between July 1, 2018, and April 1, 2020, by any durable medical equipment (DME) providers who had used a 12-month commercially available telemonitoring/coaching program (Long Term Adherence Management, Philips Respironics) in this timeframe. Patients receiving either 12 months or 3 months of support (Patient Adherence Management Service) were compared with those initiated on CPAP without support. Mean CPAP adherence was computed monthly over the initial 18 months. Missing usage was imputed as zero use. All analyses were adjusted for age, sex, and DME provider. Results: The nine DME providers using the 12-month telemonitoring/coaching service cared for a total of 26,489 patients (3,264 receiving 12-month support, 15,424 receiving 3-month support, and 7,801 receiving no support) in the timeframe under study. In adjusted analyses, mean CPAP use in the 3-month support group was greater than the no support group in Month 3 (4.6 h vs. 4.3 h; P < 0.001) but subsequently, usage declined to match the no support group at both Month 12 and Month 18. In contrast, mean CPAP use was greater in the 12-month support group than in the no support group at Month 3 (4.6 h vs. 4.3 h; P < 0.001), Month 12 (4.0 h vs. 3.6 h; P < 0.001), and Month 18 (3.3 h vs. 3.2 h; P = 0.02). Conclusions: A 3-month telemonitoring/coaching program increases CPAP use in the short term but does not lead to sustained improvements. In contrast, a 12-month program leads to sustained improvements but results still diminish once coaching ceases. Implementation of longer-term telemonitoring and coaching programs may be vital to obtaining long-term benefits from CPAP therapy.

Recipient-surgeon racial concordance in orthotopic heart transplantation outcomes.

BACKGROUND: Prior studies have demonstrated deleterious outcomes for physician-patient racial discordance. We explored recipient-surgeon racial concordance and short-term postoperative survival in adults undergoing orthotopic heart transplantation (OHT). METHODS: The United Network for Organ Sharing (UNOS) database was queried to identify White and Black adult (≥18 years) patients undergoing isolated OHT between 2000 and 2020. Surgeon race was obtained from publicly available images. All non-White and non-Black recipients and surgeons were excluded. Linear probability models were utilized to explore the relationship between recipient-surgeon racial concordance and 30-, 60-, and 90-day post-transplant mortality using a fixed effects approach. RESULTS: A total of 26,133 recipients were identified (mean age 52.79 years, 74.4% male) with 77.65% (n = 20,292) being White and 22.35% (n = 5841) being Black. A total of 662 White surgeons performed 25,946 (97.56%) OHTs during the study period while 17 Black surgeons performed 437 (1.67%) OHTs. Although some evidence of differences across groups was observed in cross-tabular specifications, these differences became insignificant after the inclusion of controls (i.e., comorbidities and fixed effects). This suggests that recipient race and physician race are not correlated with post-OHT survival at 30, 60, or 90 days. CONCLUSIONS: Recipient-surgeon racial concordance and discordance among adults undergoing OHT do not appear to impact post-transplant survival. Nor do we observe significant penalties accruing for Black patients overall once controls are accounted for. Given that worse outcomes have historically been demonstrated for Black patients undergoing OHT, further work will be necessary to improve understanding of racial disparities for patients with end-stage heart failure.

Diversity in the Adult and Pediatric Heart Transplant Surgeon Workforce between 2000 and 2020.

There is a paucity of literature evaluating trends in the demographic composition of the cardiothoracic surgery workforce. Using the United Network for Organ Sharing database, we retrospectively analyzed the changes in sex, race, and ethnicity of surgeons performing heart transplantations between 2000−2020. Surgeons performing heart transplantations for adult (≥18 years) and pediatric (<18 years) patients between 2000−2020 were identified and stratified by sex (male, female) and by race/ethnicity (non-Hispanic White, non-Hispanic Black, non-Hispanic Asian, Hispanic of any race). Between 2000−2020, the proportion of non-White and female cardiothoracic surgeons performing adult and pediatric heart transplantations increased. Nevertheless, there remains a lack of diversity in the workforce, particularly when compared to the general United States population.

Less invasive durable management of postoperative ventricular tachycardia storm after LVAD insertion.

BACKGROUND: Ventricular tachycardia (VT) can be a challenging problem in patients following durable left ventricular device (LVAD) implantation, and can lead to significant morbidity and mortality. Both the etiology and management of VT in this population can also vary substantially. CASE PRESENTATION: We herein report a case of a patient with preoperative VT who developed a drug resistant VT storm postoperatively that was ultimately controlled durably with a bedside stellate ganglion block. CONCLUSION: This case illustrates that stellate ganglion block can be an effective and durable intervention for terminating refractory VT in LVAD patients. This method is attractive because it can be performed at the bedside in relatively unstable patients, and is less invasive than other alternatives such as VT ablation and thoracic sympathectomy.

Neutralization against Omicron variant in transplant recipients after three doses of mRNA vaccine.

The SARS-CoV-2 virus Omicron variant has now supplanted wild-type virus as the dominant circulating strain globally. Three doses of mRNA COVID-19 vaccine are recommended for transplant recipients as their primary vaccine series. However, the immunogenicity of mRNA vaccines as they specifically relate to the Omicron variant are not well studied. We analyzed Omicron-specific neutralization in transplant recipients after three-doses of mRNA-1273 vaccine. Neutralization was determined using a SARS-CoV-2 spike pseudotyped lentivirus assay with constructs for Omicron and Delta variants. A total of 60 transplant patients (kidney, kidney-pancreas, lung, heart, liver) were analyzed 1 month and 3 months after completion of three doses of mRNA-1273. At 1 month, 11/60 (18.3%) patients had detectable neutralizing antibody responses to Omicron (log10 ID50 of 2.38 [range 1.34-3.57]). At 3 months, 8/51 (15.7%) were positive (median log10 ID50 [1.68; range 1.12-3.61; approximate fivefold reduction over time]). The proportion of positive patients was lower for Omicron versus wild-type, and Omicron vs. Delta (p < .001). No demographic variables were found to be significantly associated with Omicron response. Many patients with a positive anti-RBD response still had undetectable Omicron-specific neutralizing antibody. In conclusion, three doses of mRNA vaccine results in poor neutralizing responses against the Omicron variant in transplant patients.

Immune Privilege of Heart Valves.

Immune privilege is an evolutionary adaptation that protects vital tissues with limited regenerative capacity from collateral damage by the immune response. Classical examples include the anterior chamber of the eye and the brain. More recently, the placenta, testes and articular cartilage were found to have similar immune privilege. What all of these tissues have in common is their vital function for evolutionary fitness and a limited regenerative capacity. Immune privilege is clinically relevant, because corneal transplantation and meniscal transplantation do not require immunosuppression. The heart valves also serve a vital function and have limited regenerative capacity after damage. Moreover, experimental and clinical evidence from heart valve transplantation suggests that the heart valves are spared from alloimmune injury. Here we review this evidence and propose the concept of heart valves as immune privileged sites. This concept has important clinical implications for heart valve transplantation.

Patient Hand-Off iNitiation and Evaluation (PHONE) study: A randomized trial of patient handoff methods.

BACKGROUND: As residency work hour restrictions have tightened, transitions of care have become more frequent. Many institutions dedicate significant time and resources to patient handoffs despite the fact that the ideal method is relatively unknown. We sought to compare the effect of a rigorous formal handoff approach to a minimized but focused handoff process on patient outcomes. METHODS: A randomized prospective trial was conducted at a large teaching hospital over ten months. Patients were assigned to services employing either formal or focused handoffs. Residents were trained on handoff techniques and then observed by trained researchers. Outcome data including mortality, negative events, adverse events, and length of stay were collected and compared between formal and focused handoff groups using t-tests and a multivariate regression analysis. RESULTS: A total of 5157 unique patient-admissions were stratified into the two study groups. Focused handoffs were significantly shorter and included fewer patients (mean 6.3 patients discussed over 6.7 min vs. 35.2 patients over 20.6 min, both p < 0.001). Adverse events occurred during 16.7% of patient admissions. While overall length of stay was slightly shorter in the formal handoff group (5.50 days vs 5.88 days, p = 0.024) in univariate analysis only, there were no significant differences in patient outcomes between the two handoff methods (all p > 0.05). CONCLUSIONS: This large randomized trial comparing two contrasting handoff techniques demonstrated no clinically significant differences in patient outcomes. A minimalistic handoff process may save time and resources without negatively affecting patient outcomes.

Survival in HIV-positive transplant recipients compared with transplant candidates and with HIV-negative controls.

OBJECTIVES: To evaluate the impact of liver and kidney transplantation on survival in HIV-positive transplant candidates and compare outcomes between HIV-positive and negative recipients. DESIGN: Observational cohort of HIV-positive transplant candidates and recipients and secondary analysis comparing study recipients to HIV-negative national registry controls. METHODS: We fit proportional hazards models to assess transplantation impact on mortality among recipients and candidates. We compared time to graft failure and death with HIV-negative controls in unmatched, demographic-matched, and risk-adjusted models. RESULTS: There were 17 (11.3%) and 46 (36.8%) deaths among kidney and liver recipients during a median follow-up of 4.0 and 3.5 years, respectively. Transplantation was associated with survival benefit for HIV-infected liver recipients with model for end-stage liver disease (MELD) greater than or equal 15 [hazard ratio (HR) 0.1; 95% confidence interval (CI) 0.05, 0.01; P < 0.0001], but not for MELD less than 15 (HR 0.7; 95% CI 0.3, 1.8; P = 0.43) or for kidney recipients (HR 0.6; 95% CI 0.3, 1.4; P = 0.23). In HIV-positive kidney recipients, unmatched and risk-matched analyses indicated a marginally significant HR for graft loss [1.3 (P = 0.07) and HR 1.4 (P = 0.052)]; no significant increase in risk of death was observed. All models demonstrated a higher relative hazard of graft loss or death in HIV-positive liver recipients; the absolute difference in the proportion of deaths was 6.7% in the risk-matched analysis. CONCLUSION: Kidney transplantation should be standard of care for well managed HIV-positive patients. Liver transplant in candidates with high MELD confers survival benefit; transplant is a viable option in selected candidates. The increased mortality risk compared with HIV-negative recipients was modest. TRIAL REGISTRATION: ClinicalTrials.Gov; NCT00074386; http://clinicaltrials.gov/.

Geriatric Disaster Preparedness.

INTRODUCTION: The elderly population has proven to be vulnerable in times of a disaster. Many have chronic medical problems for which they depend on medications or medical equipment. Some older adults are dependent on caregivers for managing their activities of daily living (ADLs), such as dressing, and their instrumental activities of daily living (IADLs), such as transportation. Problem A coordinated effort for disaster preparation in the elderly population is paramount. This study assessed the potential needs and plans of older adults in the face of a local disaster. METHODS: The setting was a community-based, university-affiliated, urban emergency department (ED) that sees more than 77,000 adult patients per year. A survey on disaster plans and resources needed if evacuated was distributed to 100 community-residing ED patients and visitors aged 65 years and older from January through July 2013. Means and proportions are reported with 95% confidence intervals (CIs). RESULTS: Data were collected from 13 visitors and 87 patients. The mean age was 76 years, and 54% were female. Thirty-one responded that they had a disaster plan in place (31/100; CI, 22.4-41.4%). Of those 31, 94% (29/31; CI, 78.6-99.2%) had food and water as part of their plan, 62% (19/29; CI, 42.2-78.2%) had a supply of medication, and 35% (12/31; CI, 21.8-57.8%) had an evacuation plan. When asked what supplies the 100 subjects might need if evacuated, 33% (CI, 23.9-43.1%) needed a walker, 15% (CI, 8.6-23.5%) needed a wheelchair, 78% (CI, 68.6-85.7%) needed glasses, 17% (CI, 10.2-25.8%) needed a hearing aid, 16% (CI, 9.4-24.7%) needed a glucometer, 93% (CI, 86.1-97.1%) needed medication, 14% (CI, 7.8-22.4%) needed oxygen, 23% (CI, 15.2-32.5%) needed adult diapers, and 21% (CI, 13.2-30.3%) had medical equipment that required electricity. Many of the subjects also required help with one or more of their ADLS, the most common being dressing (17%; CI, 10.3-26.1%), or their IADLS, the most common being transportation (39%; CI, 29.7-49.7%). Only 42% (CI, 32.3-52.7%) were interested in learning more about disaster preparation. CONCLUSION: Only a minority of the older adults in the study population had a disaster plan in place. Most of the respondents would require medications, and many would require medical supplies if evacuated.

Isolation and characterization of antimicrobial compounds in plant extracts against multidrug-resistant Acinetobacter baumannii.

The number of fully active antibiotic options that treat nosocomial infections due to multidrug-resistant Acinetobacter baumannii (A. baumannii) is extremely limited. Magnolia officinalis, Mahonia bealei, Rabdosia rubescens, Rosa rugosa, Rubus chingii, Scutellaria baicalensis, and Terminalia chebula plant extracts were previously shown to have growth inhibitory activity against a multidrug-resistant clinical strain of A. baumannii. In this study, the compounds responsible for their antimicrobial activity were identified by fractionating each plant extract using high performance liquid chromatography, and determining the antimicrobial activity of each fraction against A. baumannii. The chemical structures of the fractions inhibiting >40% of the bacterial growth were elucidated by liquid chromatography/mass spectrometry analysis and nuclear magnetic resonance spectroscopy. The six most active compounds were identified as: ellagic acid in Rosa rugosa; norwogonin in Scutellaria baicalensis; and chebulagic acid, chebulinic acid, corilagin, and terchebulin in Terminalia chebula. The most potent compound was identified as norwogonin with a minimum inhibitory concentration of 128 µg/mL, and minimum bactericidal concentration of 256 µg/mL against clinically relevant strains of A. baumannii. Combination studies of norwogonin with ten anti-Gram negative bacterial agents demonstrated that norwogonin did not enhance the antimicrobial activity of the synthetic antibiotics chosen for this study. In conclusion, of all identified antimicrobial compounds, norwogonin was the most potent against multidrug-resistant A. baumannii strains. Further studies are warranted to ascertain the prophylactic and therapeutic potential of norwogonin for infections due to multidrug-resistant A. baumannii.