"An app is just available at all times"-the process and outcomes of converting the Georgia Tuberculosis Reference Guide into a mobile application

BACKGROUND

The physical, paper-based Georgia TB Reference Guide has served as the clinical reference handbook on tuberculosis (TB) diagnostic and treatment guidelines for the state of Georgia in the United States. Supported by the Georgia Department of Public Health, the production of the 112-page palm-sized booklet was previously led by a team of Georgia-based TB experts at Emory University and printed every three-five years with updates to clinical management guidelines and TB consult contact information. However, the costs associated with editorial printing combined with delays in updating a static printed booklet with revised guidance hampered the utility of the tool. Considering the barriers with paper-based production and based on the beneficial use of apps to support the dissemination of clinical management guidance in other settings, the booklet was converted into a mobile application. This paper describes the process of developing a mobile app version of the Georgia TB Reference Guide in an easy-to-update and readily available format.

METHODS

We employed a user-centered design approach to develop the app, including a series of qualitative interviews and quantitative surveys. Participants included a mix of state officials and local TB experts. First, initial foundational interviews were conducted to conceptualize current utilization practices of both the paper and PDF versions of the tool. Second, the findings from the initial interviews were organized thematically and informed the design of the app, which was then beta tested by a round of previously unsampled TB experts as well as a re-sample from the initial interviews. Third, the designs were coded into developmental phases and beta tested among users of the current Georgia TB Reference Guide. Fourth, the app was published and downloaded by a pre-selected group of local users who provided answers to a follow-up survey after using the app for one month. Fifth, user growth, self-reported demographics, and app usage between February and July 2022 were recorded through automatic data metrics built into the app.

RESULTS

The paper copy Georgia TB Reference Guide usage themes included commonly referenced content, navigation paths, and desired features and content. The themes were converted into features and designs such as prioritizing commonly reviewed topics and guide customization with bookmarks and notes. Iterations of the designs were driven by feedback from TB experts and included home page featured content, improving content readability, and improving the search feature. The follow-up survey revealed a 90% preference for the app over the paper version of the guide. In the six months following the app's release, the app was downloaded by 281 individuals in the United States. The majority of downloads were in Georgia and the app also expanded organically to 19 other states.

CONCLUSION

The experience of converting the Georgia TB Reference Guide offers specific and effective steps to converting a medical reference guide into a mobile application tool that is readily available, easy to use, and easy to update. The organic dissemination of the app beyond the state of Georgia's borders within the first six months of app launch underscores desire among TB healthcare professionals for high-quality digital reference content outside the state. This experience offers clear outlines for replication in other contexts and demonstrates the utility of similar mobile medical reference tools.

Feasibility of Multiparametric Perfusion Assessment in Diabetic Foot Ulcer Using Intravoxel Incoherent Motion and Blood Oxygenation-Level Dependent MRI

BACKGROUND

Patients with type-2 diabetes (T2DM) are at increased risk of developing diabetic foot ulcers (DFU) and experiencing impaired wound healing related to underlying microvascular disease.

PURPOSE

To evaluate the sensitivity of intra-voxel incoherent motion (IVIM) and blood oxygen level dependent (BOLD) MRI to microvascular changes in patients with DFUs.

STUDY TYPE

Case-control.

POPULATION

20 volunteers who were age and body mass index matched, including T2DM patients with DFUs (N = 10, mean age = 57.5 years), T2DM patients with controlled glycemia and without DFUs (DC, N = 5, mean age = 57.4 years) and healthy controls (HC, N = 5, mean age = 52.8 years).

FIELD STRENGTH/SEQUENCE

3T/multi-b-value IVIM and dynamic BOLD.

ASSESSMENT

Resting IVIM parameters were obtained using a multi-b-value diffusion-weighted imaging sequence and two IVIM models were fit to obtain diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f) and microvascular volume fraction (MVF) parameters. Microvascular reactivity was evaluated by inducing an ischemic state in the foot with a blood pressure cuff during dynamic BOLD imaging. Perfusion indices were assessed in two regions of the foot: the medial plantar (MP) and lateral plantar (LP) regions.

STATISTICAL TESTS

Effect sizes of group mean differences were assessed using Hedge's g adjusted for small sample sizes.

RESULTS

DFU participants exhibited elevated D*, f, and MVF values in both regions (g ≥ 1.10) and increased D (g = 1.07) in the MP region compared to DC participants. DC participants showed reduced f and MVF compared to HC participants in the MP region (g ≥ 1.06). Finally, the DFU group showed reduced tolerance for ischemia in the LP region (g = -1.51) and blunted reperfusion response in both regions (g < -2.32) compared to the DC group during the cuff-occlusion challenge.

DATA CONCLUSION

The combined use of IVIM and BOLD MRI shows promise in differentiating perfusion abnormalities in the feet of diabetic patients and suggests hyperperfusion in DFU patients.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 1.

Impact of Prior Tuberculosis Treatment With New/Companion Drugs on Clinical Outcomes in Patients Receiving Concomitant Bedaquiline and Delamanid for Multidrug- and Rifampicin-Resistant Tuberculosis

BACKGROUND

There are scarce data on the clinical outcomes of persons retreated with new/companion anti-tuberculosis (TB) drugs for multidrug- and rifampicin-resistant tuberculosis (MDR/RR-TB). We sought to evaluate the efficacy and safety of bedaquiline and delamanid containing regimens among patients with and without prior exposure to the new/companion drugs (bedaquiline, delamanid, linezolid, clofazimine, and fluoroquinolones).

METHODS

We conducted a retrospective cohort study among patients with pulmonary MDR/RR-TB in Georgia who received bedaquiline and delamanid combination as a part of a salvage regimen from November 2017 to December 2020 in a programmatic setting.

RESULTS

Among 106 persons with a median age of 39.5 years, 44 (41.5%) were previously treated with new/companion TB drugs. Patients with prior exposure to new/companion drugs had higher rates of baseline resistance compared to those without exposure to new/companion TB drugs (bedaquiline 15.2% vs 1.8%, linezolid 22.2% vs 16.7%). Sputum culture conversion rates among patients exposed and not exposed to new/companion drugs were 65.9% vs 98.0%, respectively (P < .001). Among patients with and without prior new/companion TB drug use, favorable outcome rates were 41.0% and 82.3%, respectively (P < .001). Treatment adherence in 32 (30.2%) patients was ≤80%. Five of 21 patients (23.8%) who had a baseline and repeat susceptibility test had acquired bedaquiline resistance. QTC/F prolongation (>500 ms) was rare (2.8%).

CONCLUSIONS

Prior exposure to new/companion TB drugs was associated with poor clinical outcomes and acquired drug resistance. Tailoring the TB regimen to each patient's drug susceptibility test results and burden of disease and enhancing adherence support may improve outcomes.

Intelligent Care Management for Diabetic Foot Ulcers: A Scoping Review of Computer Vision and Machine Learning Techniques and Applications

Ten percent of adults in the United States have a diagnosis of diabetes and up to a third of these individuals will develop a diabetic foot ulcer (DFU) in their lifetime. Of those who develop a DFU, a fifth will ultimately require amputation with a mortality rate of up to 70% within five years. The human suffering, economic burden, and disproportionate impact of diabetes on communities of color has led to increasing interest in the use of computer vision (CV) and machine learning (ML) techniques to aid the detection, characterization, monitoring, and even prediction of DFUs. Remote monitoring and automated classification are expected to revolutionize wound care by allowing patients to self-monitor their wound pathology, assist in the remote triaging of patients by clinicians, and allow for more immediate interventions when necessary. This scoping review provides an overview of applicable CV and ML techniques. This includes automated CV methods developed for remote assessment of wound photographs, as well as predictive ML algorithms that leverage heterogeneous data streams. We discuss the benefits of such applications and the role they may play in diabetic foot care moving forward. We highlight both the need for, and possibilities of, computational sensing systems to improve diabetic foot care and bring greater knowledge to patients in need.

Implementation of Bedaquiline, Pretomanid, and Linezolid in the United States: Experience Using a Novel All-Oral Treatment Regimen for Treatment of Rifampin-Resistant or Rifampin-Intolerant Tuberculosis Disease

BACKGROUND

Rifampin-resistant tuberculosis is a leading cause of morbidity worldwide; only one-third of persons start treatment, and outcomes are often inadequate. Several trials demonstrate 90% efficacy using an all-oral, 6-month regimen of bedaquiline, pretomanid, and linezolid (BPaL), but significant toxicity occurred using 1200-mg linezolid. After US Food and Drug Administration approval in 2019, some US clinicians rapidly implemented BPaL using an initial 600-mg linezolid dose adjusted by serum drug concentrations and clinical monitoring.

METHODS

Data from US patients treated with BPaL between 14 October 2019 and 30 April 2022 were compiled and analyzed by the BPaL Implementation Group (BIG), including baseline examination and laboratory, electrocardiographic, and clinical monitoring throughout treatment and follow-up. Linezolid dosing and clinical management was provider driven, and most patients had linezolid adjusted by therapeutic drug monitoring.

RESULTS

Of 70 patients starting BPaL, 2 changed to rifampin-based therapy, 68 (97.1%) completed BPaL, and 2 of the 68 (2.9%) experienced relapse after completion. Using an initial 600-mg linezolid dose daily adjusted by therapeutic drug monitoring and careful clinical and laboratory monitoring for adverse effects, supportive care, and expert consultation throughout BPaL treatment, 3 patients (4.4%) with hematologic toxicity and 4 (5.9%) with neurotoxicity required a change in linezolid dose or frequency. The median BPaL duration was 6 months.

CONCLUSIONS

BPaL has transformed treatment for rifampin-resistant or intolerant tuberculosis. In this cohort, effective treatment required less than half the duration recommended in 2019 US guidelines for drug-resistant tuberculosis. Use of individualized linezolid dosing and monitoring likely enhanced safety and treatment completion. The BIG cohort demonstrates that early implementation of new tuberculosis treatments in the United States is feasible.

Diabetes Mellitus and Tuberculosis Treatment Outcomes: Interaction Assessment Between Hyperglycemia and Human Immunodeficiency Virus in the State of Georgia, 2015-2020

Background

Diabetes mellitus and human immunodeficiency virus (HIV) are independent risk factors for poor outcomes among people with tuberculosis (TB). To date, information on the joint impact of diabetes and HIV on TB outcomes is limited. We aimed to estimate (1) the association between hyperglycemia and mortality and (2) the effect of joint exposure to diabetes and HIV on mortality.

Methods

We conducted a retrospective cohort study among people with TB in the state of Georgia between 2015 and 2020. Eligible participants were 16 or older, did not have a previous TB diagnosis, and were microbiologically confirmed or clinical cases. Participants were followed during TB treatment. Robust Poisson regression was used to estimate risk ratios for all-cause mortality. Interaction between diabetes and HIV was assessed on the additive scale using the attributable proportion and on the multiplicative scale with product terms in regression models.

Results

Of 1109 participants, 318 (28.7%) had diabetes, 92 (8.3%) were HIV positive, and 15 (1.4%) had diabetes and HIV. Overall, 9.8% died during TB treatment. Diabetes was associated with an increased risk of death among people with TB (adjusted risk ratio [aRR] = 2.59; 95% confidence interval [CI], 1.62-4.13). We estimated that 26% (95% CI, -43.4% to 95.0%) of deaths among participants with diabetes mellitus and HIV were due to biologic interaction.

Conclusions

Diabetes alone and co-occurring diabetes and HIV were associated with an increased risk of all-cause mortality during TB treatment. These data suggest a potential synergistic effect between diabetes and HIV.

Using the National Institute on Minority Health and Health Disparities framework to better understand disparities in major amputations

Recently, the United States experienced its first resurgence of major amputations in more than 20 years. Compounding this rise is a longstanding history of disparities. Patients identifying as non-Hispanic Black are twice as likely to lose a limb as those identifying as non-Hispanic White. Those identifying as Latino face a 30% increase. Rural patients are also more likely to undergo major amputations, and the rural-urban disparity is widening. We used the National Institute on Minority Health and Health Disparities framework to better understand these disparities and identify common factors contributing to them. Common factors were abundant and included increased prevalence of diabetes, possible lower rates of foot self-care, transportation barriers to medical appointments, living in disadvantaged neighborhoods, and lack of insurance. Solutions within and outside the health care realm are needed. Health care-specific interventions that embed preventative and ambulatory care services within communities may be particularly high yield.

Outpatient Parenteral Antibiotic Therapy for Diabetic Foot Osteomyelitis in an Uninsured and Underinsured Cohort

Background

Diabetic foot osteomyelitis (DFO) is usually treated with prolonged outpatient parenteral antibiotic therapy (OPAT). Evaluation and treatment of non-antibiotic aspects of DFO (e.g., peripheral artery disease [PAD]) are also recommended. There is limited data regarding OPAT practice patterns and outcomes for DFO.

Methods

Single-center observational study of patients receiving OPAT for DFO in a large United States public hospital between January 2017 and July 2019. We abstracted data regarding microbiology test, antibiotics, clinical outcomes, and non-antibiotic DFO management.

Results

Ninety-six patients were included and some had >1 DFO-OPAT course during the study period (106 DFO-OPAT courses included). No culture was obtained in 40 (38%) of courses. Methicillin-resistant S. aureus (MRSA) was cultured in 15 (14%) and P. aeruginosa in 1 (1%) of DFO-OPAT courses. An antibiotic with MRSA activity (vancomycin or daptomycin) was used in 79 (75%) of courses and a parenteral antibiotic with anti-pseudomonal activity was used in 7 (6%) of courses. Acute kidney injury occurred in 19 (18%) DFO-OPAT courses. An ankle-brachial index measurement was obtained during or 6 months prior to the first DFO-OPAT course for 44 (49%) of patients. Forty-two (44%) patients died or had an amputation within 12 months of their initial hospital discharge.

Conclusions

We found high rates of empiric antibiotic therapy for DFO and low uptake of the non-antibiotic aspects of DFO care. Better implementation of microbiological tests for DFO in addition to stronger integration of infectious disease and non-infectious diseases care could improve DFO outcomes.

What Is the Best Oral Therapy for Staph aureus Osteomyelitis?

Best Oral Therapy for Staph aureus OsteomyelitisA 50-year-old patient with diabetes mellitus has a plantar ulcer at the base of the first metatarsal. Cortical erosions are noted; bone biopsy culture yields Staphylococcus aureus susceptible to methicillin, ciprofloxacin, clindamycin, doxycycline, trimethoprim/sulfamethoxazole, linezolid, and rifampin. The plan is for 4 weeks of antibiotic treatment. Which antibiotic should be prescribed?

Outpatient clinic attendance and outcomes among patients hospitalized with diabetic foot ulcers

BACKGROUND

There are limited data on post-hospital discharge clinic attendance rates and outcomes among patients with diabetic foot ulcers (DFUs).

METHODS

Retrospective study of patients hospitalized with a DFU from 2016 to 2019 in a large public hospital. We measured rates and predictors of clinic attendance with providers involved with DFU care within 30 days of hospital discharge ("30-day post-discharge clinic attendance"). Log-binomial regression was used to estimate risk ratios (RR) and 95 % confidence intervals (CI).

RESULTS

Among 888 patients, 60.0 % were between 45 and 64 years old, 80.5 % were Black, and 24.1 % were uninsured. Overall, 478 (53.8 %) attended ≥1 30-day post-discharge clinic appointment. Initial hospital outcomes were associated with clinic attendance. For example, the RR of 30-day post-discharge clinic attendance was 1.39 (95%CI 1.19-1.61) among patients who underwent a major amputation compared to patients with DFUs without osteomyelitis and did not undergo an amputation during the initial hospitalization. Among 390 patients with known 12-month outcome, 71 (18.2 %) had a major amputation or died ≤12 months of hospital discharge.

CONCLUSION

We found a low post-discharge clinic attendance and high post-discharge amputation and death rates among patients hospitalized with DFUs. Interventions to increase access to outpatient DFU care are needed and could prevent amputations.

Updating the approaches to define susceptibility and resistance to anti-tuberculosis agents: implications for diagnosis and treatment

Approximately 85 000 deaths globally in 2019 were due to drug-resistant tuberculosis (TB), which corresponds to 7% of global deaths attributable to bacterial antimicrobial resistance [1]. Yet concerns have been mounting that drug-resistant TB was being underestimated because the approaches to define susceptibility and resistance to anti-TB agents had not kept up with those used for other major bacterial pathogens [2–9]. Here, we outline the recent, evidence-based initiatives spearheaded by the World Health Organization (WHO) and others to update breakpoints (traditionally referred to as critical concentrations (CCs)) that are used for phenotypic antimicrobial susceptibility testing (AST), also called drug susceptibility testing in the TB literature.

Inappropriately high breakpoints have resulted in systematic false-susceptible AST results to anti-TB drugs. MIC, PK/PD and clinical outcome data should be combined when setting breakpoints to minimise the emergence and spread of antimicrobial resistance. https://bit.ly/3i43wb6

Risk-Factors for Exposure Associated With SARS-CoV-2 Detection After Recent Known or Potential COVID-19 Exposures Among Patients Seeking Medical Care at a Large Urban, Public Hospital in Fulton County, Georgia - A Cross-Sectional Investigation

We aimed to describe frequency of COVID-19 exposure risk factors among patients presenting for medical care at an urban, public hospital serving mostly uninsured/Medicare/Medicaid clients and risk factors associated with SARS-CoV-2 infection. Consenting, adult patients seeking care at a public hospital from August to November 2020 were enrolled in this cross-sectional investigation. Saliva, anterior nasal and nasopharyngeal swabs were collected and tested for SARS-CoV-2 using RT-PCR. Participant demographics, close contact, and activities ≤14 days prior to enrollment were collected through interview. Logistic regression was used to identify risk factors associated with testing positive for SARS-CoV-2. Among 1,078 participants, 51.8% were male, 57.0% were aged ≥50 years, 81.3% were non-Hispanic Black, and 7.6% had positive SARS-CoV-2 tests. Only 2.7% reported COVID-19 close contact ≤14 days before enrollment; this group had 6.79 adjusted odds of testing positive (95%CI = 2.78-16.62) than those without a reported exposure. Among participants who did not report COVID-19 close contact, working in proximity to ≥10 people (adjusted OR = 2.17; 95%CI = 1.03-4.55), choir practice (adjusted OR = 11.85; 95%CI = 1.44-97.91), traveling on a plane (adjusted OR = 5.78; 95%CI = 1.70-19.68), and not participating in an essential indoor activity (i.e., grocery shopping, public transit use, or visiting a healthcare facility; adjusted OR = 2.15; 95%CI = 1.07-4.30) were associated with increased odds of testing positive. Among this population of mostly Black, non-Hispanic participants seeking care at a public hospital, we found several activities associated with testing positive for SARS-CoV-2 infection in addition to close contact with a case. Understanding high-risk activities for SARS-CoV-2 infection among different communities is important for issuing awareness and prevention strategies.

Specimen self-collection for SARS-CoV-2 testing: Patient performance and preferences—Atlanta, Georgia, August-October 2020

Self-collected specimens can expand access to SARS-CoV-2 testing. At a large inner-city hospital 1,082 participants self-collected saliva and anterior nasal swab (ANS) samples before healthcare workers collected nasopharyngeal swab (NPS) samples on the same day. To characterize patient preferences for self-collection, this investigation explored ability, comfort, and ease of ANS and saliva self-collection for SARS-CoV-2 testing along with associated patient characteristics, including medical history and symptoms of COVID-19. With nearly all participants successfully submitting a specimen, favorable ratings from most participants (at least >79% in ease and comfort), and equivocal preference between saliva and ANS, self-collection is a viable SARS-CoV-2 testing option.

Mycobacterium bovis Bacillus Calmette-Guérin Cross-Contamination in the Operating Room: A Case Report

Mycobacterium tuberculosis complex (MTBC) false-positive cultures are commonly attributed to laboratory cross-contamination, but cross-contamination in the operating room (OR) is seldom reported. We report an investigation of cross-contamination in the OR for our case patient, who underwent surgical intervention for a chronic, left-sided breast lesion. Although the case patient had never received Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccine or chemotherapy, a subsequent surgical sample culture was identified as MTBC by high-performance liquid chromatography and M. bovis BCG-type by genotyping. A collaborative false-positive investigation was initiated, and we discovered a cross-contamination event in the OR from a source case who received BCG intravesical instillation. Clinicians, public health, and infection control staff should be aware that MTBC cross-contamination in the OR is rare, but possible, and should recognize the importance of conducting thorough false-positive investigations.

Hyperinflammatory Syndromes After Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Messenger RNA vaccination in Individuals With Underlying Immune Dysregulation

The development of effective severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger RNA (mRNA) vaccines has been a significant accomplishment. Adverse events are extremely rare, but continued surveillance is important, especially in at-risk populations. In 5 patients with preexisting immune dysregulation, hyperinflammatory syndromes, including hemophagocytic lymphohistiocytosis, developed after SARS-CoV-2 mRNA vaccination. Early recognition of this rare condition is essential.

Effects of Patient Characteristics on Diagnostic Performance of Self-Collected Samples for SARS-CoV-2 Testing

We evaluated the performance of self-collected anterior nasal swab (ANS) and saliva samples compared with healthcare worker–collected nasopharyngeal swab specimens used to test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We used the same PCR diagnostic panel to test all self-collected and healthcare worker–collected samples from participants at a public hospital in Atlanta, Georgia, USA. Among 1,076 participants, 51.9% were men, 57.1% were >50 years of age, 81.2% were Black (non-Hispanic), and 74.9% reported >1 chronic medical condition. In total, 8.0% tested positive for SARS-CoV-2. Compared with nasopharyngeal swab samples, ANS samples had a sensitivity of 59% and saliva samples a sensitivity of 68%. Among participants tested 3–7 days after symptom onset, ANS samples had a sensitivity of 80% and saliva samples a sensitivity of 85%. Sensitivity varied by specimen type and patient characteristics. These findings can help physicians interpret PCR results for SARS-CoV-2.

Epidemiologic, immunologic, and virus characteristics in patients with paired SARS-CoV-2 serology and reverse transcription polymerase chain reaction testing

BACKGROUND

The natural history and clinical progression of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections can be better understood using combined serological and reverse transcription polymerase chain reaction (RT-PCR) testing.

METHODS

Nasopharyngeal swabs and serum were collected at a single time-point from patients at an urban, public hospital August - November 2020 and tested for SARS-CoV-2 using RT-PCR, viral culture, and anti-Spike pan-Ig antibody testing. Participant demographics and symptoms were collected through interview. Chi-squared and Fisher's exact tests were used to identify associations between RT-PCR and serology results with presence of viable virus and frequency of symptoms.

RESULTS

Among 592 participants, 129 (21.8%) had evidence of SARS-CoV-2 infection by RT-PCR or serology. Presence of SARS-CoV-2 antibodies was strongly associated with lack of viable virus (p-value=0.016). COVID-19 symptom frequency was similar for patients testing RT-PCR positive/seronegative and patients testing RT-PCR positive/seropositive. Patients testing RT-PCR positive/seronegative reported headaches, fatigue, diarrhea and vomiting at rates not statistically significantly different from those testing RT-PCR negative/seropositive.

CONCLUSIONS

While patients testing SARS-CoV-2 seropositive were unlikely to test positive for viable virus and were therefore low-risk for forward transmission, COVID-19 symptoms were common. Paired SARS-CoV-2 RT-PCR and antibody testing provides more nuanced understanding of patients' COVID-19 status.

Applying the Infectious Diseases Literature to People who Inject Drugs

People who inject drugs (PWID) presenting with injection drug use-associated infections are an understudied population excluded from most prospective infectious disease (ID) clinical trials. Careful application of the existing ID literature to PWID must consider their unique medical, psychological, and social challenges. Identification and treatment of the underlying substance use disorder are key underpinnings to any successful ID intervention.

Barriers to diabetic foot care in a disadvantaged population: A qualitative assessment

OBJECTIVE

We explored barriers to proper foot care in this population using a qualitative approach with focus group discussions (FGD).

METHODS

Participants were recruited from clinics at a safety-net hospital in Atlanta, Georgia and stratified into two groups: diabetic foot ulcer (DFU) and minor amputation (below ankle). The FGDs addressed patient experience in receiving care with a goal of understanding: foot care knowledge, barriers to care, and preferred educational methods. Surveys were performed to supplement FGDs.

RESULTS

Forty participants (90% Black) were enrolled. Dominant themes emerging from FGDs were: 1-Patients reported adequate understanding of recommended foot care practices; 2-Personal barriers to self-care included lack of motivation, high cost, poor insurance coverage of supplies, and difficulty limiting activity for proper offloading; 3-Hospital system barriers included difficulty making timely appointments and reaching a provider to arrange care; 4-Access to footcare-related information and services improved with greater disease severity. Participants stressed that improved access often came too late to alter their course. They expressed interest in developing peer support groups to facilitate learning and sharing information relating to DFU.

CONCLUSION

We found that patients with DFU or minor amputations have adequate footcare-related knowledge, but personal and systemic barriers limited appropriate foot care.

Percutaneous Bone Biopsy for Diabetic Foot Osteomyelitis: A Systematic Review and Meta-Analysis

Background

Diabetes is the leading cause of lower extremity nontraumatic amputation globally, and diabetic foot osteomyelitis (DFO) is usually the terminal event before limb loss. Although guidelines recommend percutaneous bone biopsy (PBB) for microbiological diagnosis of DFO in several common scenarios, it is unclear how frequently PBBs yield positive cultures and whether they cause harm or improve outcomes.

Methods

We searched the PubMed, EMBASE, and Cochrane Trials databases for articles in any language published up to December 31, 2019, reporting the frequency of culture-positive PBBs. We calculated the pooled proportion of culture-positive PBBs using a random-effects meta-analysis model and reported on PBB-related adverse events, DFO outcomes, and antibiotic adjustment based on PBB culture results where available.

Results

Among 861 articles, 11 studies met inclusion criteria and included 780 patients with 837 PBBs. Mean age ranged between 56.6 and 71.0 years old. The proportion of males ranged from 62% to 86%. All studies were longitudinal observational cohorts, and 10 were from Europe. The range of culture-positive PBBs was 56%-99%, and the pooled proportion of PBBs with a positive culture was 84% (95% confidence interval, 73%-91%). There was heterogeneity between studies and no consistency in definitions used to define adverse events. Impact of PBB on DFO outcomes or antibiotic management were seldom reported.

Conclusions

This meta-analysis suggests PBBs have a high yield of culture-positive results. However, this is an understudied topic, especially in low- and middle-income countries, and the current literature provides very limited data regarding procedure safety and impact on clinical outcomes or antibiotic management.

Performance of a rapid two-sequence screening protocol for osteomyelitis of the foot

OBJECTIVE

Compare a two sequence protocol to a standard protocol in the detection of pedal osteomyelitis (OM) and abscesses and to identify patients that benefit from a full protocol.

MATERIALS AND METHODS

One hundred thirty-two foot MRIs ordered to assess for OM were enrolled, and the following items were extracted from the clinical reports: use of IV contrast, the presence of OM, reactive osteitis, and a soft tissue abscess. Using only one T1 nonfat-suppressed and one fluid sensitive fat-suppressed sequences, two experienced musculoskeletal radiologists reviewed each case for the presence of OM, reactive osteitis, or an abscess. A Kappa test was calculated to assess for interobserver agreement, and diagnostic performance was determined. The McNemar test was used to assess for the effect of contrast.

RESULTS

Agreement between both observers and the clinical report on the presence of osteomyelitis was substantial ( k = 0.63 and 0.72, p < 0.001), while the agreement for abscess was fair (k = 0.29 and 0.38, p < 0.001). For osteomyelitis, both observers showed good accuracy (0.85 and 0.86). When screening bone for a normal versus abnormal case, this method was highly sensitive (0.97-0.98), but was less sensitive for abscess (0.63-0.75). Fifty-one percent of exams used contrast, and it did impact the diagnosis of abscess for one observer.

CONCLUSION

This rapid protocol is accurate in making the diagnosis of OM, and its high sensitivity makes it useful to screen for patients that would benefit from a full protocol.

Internal thoracic lymphadenopathy and pulmonary tuberculosis

OBJECTIVE

Internal thoracic lymphadenopathy (ITL) has been associated with malignancies and non-tuberculous empyema. However, the association between ITL and active pulmonary tuberculosis (PTB) and the correlation between ITL and other imaging characteristics of active PTB has not been examined.

MATERIALS AND METHODS

A retrospective cohort study comprising 137 adults with active PTB who had a concomitant chest CT over a seven-year period was conducted. Two thoracic radiologists evaluated for ITL as well as nine other imaging characteristics of active tuberculosis, including total lung involvement (as measured by a total severity score), number of nodules, presence of tree-in-bud nodularity, highest extent of tree-in-bud nodularity in a lobe, miliary pattern, cavitary lesions, pleural effusion, lymphadenopathy (excluding internal thoracic lymph nodes), and empyema. The Wilcoxon rank-sum test and chi-squared tests were used to assess the correlation between ITL and additional imaging findings.

RESULTS

Internal thoracic lymphadenopathy was present in 50 of 137 cases (36.5%); most commonly bilateral (19.0%) or isolated on the right side (13.7%), and less commonly isolated on the left side (3.7%). Pleural effusion, lymphadenopathy (apart from internal thoracic compartment), and empyema all showed statistically significant correlations with ITL (p-values of <0.0001).

CONCLUSIONS

While the presence of ITL - particularly when accompanied by other imaging findings such as pleural effusion - may prompt a radiologist to first consider malignancy, active PTB should be an additional consideration in the appropriate clinical context.

Evaluation of a comprehensive diabetic foot ulcer care quality model

AIMS

Diabetes-related amputations are typically preceded by a diabetic foot ulcer (DFU) but models to assess the quality of care are lacking. We investigated a model to measure inpatient and outpatient quality.

METHODS

Cohort study among adults hospitalized with a DFU to a safety-net hospital during 2016. We measured adherence to DFU-related quality metrics based on guidelines during and 12 months following hospitalization. Inpatient metrics included ankle-brachial index measurement during or 6 months prior to hospitalization, receiving diabetes education and a wound offloading device prior to discharge. Outpatient metrics included wound care ≤30 days of discharge, in addition to hemoglobin A1c (HbA1c) ≤8%, tobacco cessation, and retention in care (≥2 clinic visits ≥90 days apart) 12 months following discharge.

RESULTS

323 patients were included. Regarding inpatient metrics, 8% had an ankle brachial index measurement, 37% received diabetes education, and 20% received offloading prior to discharge. Regarding outpatient metrics, 33% received wound care ≤30 days of discharge. Twelve months following discharge, 34% achieved a HbA1c ≤8%, 13% quit tobacco, and 52% were retained in care. Twelve-month amputation-free survival was 71%.

CONCLUSIONS

Our model demonstrated large gaps in DFU guideline-adherent care. Implementing measures to close these gaps could prevent amputations.

Linezolid use for drug-resistant tuberculosis in Georgia: a retrospective cohort study

SETTING: Data on the long-term use of linezolid (LZD) in the treatment of drug-resistant pulmonary tuberculosis (DR-PTB) are limited.OBJECTIVE: To assess safety, tolerability and efficacy of LZD-containing regimens for the treatment of DR-PTB in the country of Georgia.DESIGN: A retrospective study was conducted among DR-PTB patients receiving LZD 600 mg/day as part of newly implemented regimens (bedaquiline or delamanid, repurposed and second-line drugs) from July 2014 to October 2015 in programmatic conditions and following WHO recommendations.RESULTS: One hundred mostly male (82%) patients with a median age of 33 years received LZD. Most patients (77%) had previously been treated for TB; 57% had extensively drug-resistant TB. The median duration of LZD use was 503 days (interquartile range 355-616). LZD-associated adverse events occurred in 12 patients, leading to discontinuation in 4 (2 each due to peripheral neuropathy and cytopenias), and dose reduction to 300 mg/day in 6 cases (4 due to peripheral neuropathy and 2 for cytopenias). Almost all patients (95%) achieved culture conversion and 79% had a successful treatment outcomes.CONCLUSION: Treatment regimens including lengthy LZD use showed fairly good safety and tolerability and were associated with high rates of culture conversion and favorable outcomes.

459. Gaps in Diabetic Foot Care in an Inner-City Hospital

Background

Diabetic foot disease is the leading cause of preventable limb loss in the United States. Care continuum models to measure gaps in care are lacking.

Methods

Retrospective cohort study conducted in an urban safety-net hospital in Atlanta, GA (Grady Memorial Hospital). All patients admitted between January-May 2016 with diabetes-related foot ulcer, osteomyelitis, or for lower-extremity amputation were included. A care continuum model for inpatient and post-discharge outpatient metrics was developed based on national guidelines and available diabetes care continuum models (figure). We followed patients for 12 months after initial hospital admission.

Results

Among 123 patients, the median age was 56 (IQR 48–64) years and most were male (67%) and black (83%) (table). Prior to hospital admission, 12% of patients had a major amputation (above ankle) and 21% had a minor amputation (below ankle). Tobacco use (34%), homelessness (29%), and no medical insurance (20%) rates were high. Few patients (28%) had hemoglobin A1c (Hb1Ac) at goal (≤7.5%) and 10% had end-stage renal disease. Regarding inpatient care metrics, 59% had a median glucose at goal on the day of discharge (≤180 gm/dL). Few patient patients had a noninvasive vascular test (13%) or received a wound offloading device (16%) during hospitalization. Regarding post-discharge outpatient metrics, 33% had wound care ≤30 days after hospitalization, 14% with tobacco use at baseline quit, and 24% had Hb1c ≤7.5%. Emergency room (ER) visits and hospital readmissions within 12 months post-discharge were common (77% and 66%, respectively). Only 54% were retained in care (≥2 clinic visits ≥90 days apart). Outcomes during 12 months after the first day of initial hospital admission were poor: 6% died, 23% had a new major amputation and 22% had a new minor amputation. Including major amputations prior to initial hospital admission, 37% of patients died or were living with a major amputation 12 months after hospitalization.

Conclusion

Our care continuum model demonstrated large gaps in diabetic foot care. Over a third of these patients died or were living with major limb loss and there were high rates of ER visits and hospital readmissions. Implementing measures to close gaps in care could improve outcomes.

Disclosures

All authors: No reported disclosures.

Increasing Number and Volume of Cavitary Lesions on Chest Computed Tomography Are Associated With Prolonged Time to Culture Conversion in Pulmonary Tuberculosis

Background

Cavitary lesions (CLs) primarily identified by chest x-ray (CXR) have been associated with worse clinical outcomes among patients with pulmonary tuberculosis (PTB). Chest computed tomography (CT), which has better resolution and increased sensitivity to detect lung abnormalities, has been understudied in PTB patients. We compared detection of CLs by CT and CXR and assessed their association with time to sputum culture conversion (tSCC).

Methods

This was a retrospective cohort study of 141 PTB patients who underwent CT. We used multivariate Cox proportional hazards models to evaluate the association between CLs on CXR and the number and single largest volume of CLs on CT with tSCC.

Results

Thirty (21%) and 75 (53%) patients had CLs on CXR and CT, respectively. CT detected cavities in an additional 44 patients (31%) compared with CXR. After multivariable adjustment, we observed a negative association between CLs and tSCC, with an adjusted hazard ratio (aHR) of 0.56 (95% confidence interval [CI], 0.32 to 0.97) for single CLs and 0.31 (95% CI, 0.16 to 0.60) for multiple CLs present on CT. Patients with a CL volume ≥25 mL had a prolonged tSCC (aHR, 0.39; 95% CI, 0.21 to 0.72). CLs on CXR were not associated with increased tSCC after multivariable adjustment.

Conclusions

CT detected a larger number of cavities in patients with PTB relative to CXR. We observed an association between increasing number and volume of CLs on CT and delayed tSCC independent of sputum microscopy result. Our findings highlight a potential role for CT in the clinical and research setting as a tool to risk-stratify patients with PTB.

Disparity in Quality of Infectious Disease vs Addiction Care Among Patients With Injection Drug Use-Associated Staphylococcus aureus Bacteremia

Evidence-based interventions for Staphylococcus aureus bacteremia (SAB) are well known, but it is unclear how they are implemented among patients with injection drug use-associated (IDU) SAB. Of 46 patients with IDU-SAB identified, all received high-quality SAB management; however, few received appropriate recognition or treatment of their underlying substance use disorder.

High Yield of Active Tuberculosis Case Finding Among HIV-Infected Patients Using Xpert MTB/RIF Testing

Objective

Conduct an active case finding study in Tbilisi, Georgia, for pulmonary tuberculosis (TB) among people living with HIV (PLWH).

Methods

Newly diagnosed HIV patients were assessed for symptoms and asked to submit sputum samples for smear microscopy, culture, and molecular diagnostic testing (Xpert MTB/RIF).

Results

Among 276 PLWH, 131 agreed to participate and 103 submitted sputum samples. Most participants were male (70%) and mean age of 43 years. There were high rates of a positive hepatitis C virus (HCV) antibody test (46%) and the median CD4 count was 122 cells/mm³. A total of 15 (11.5%) persons were diagnosed with pulmonary TB, including 1 each with multidrug-resistant and isoniazid-resistant disease. Twelve had a positive culture for Mycobacterium tuberculosis and Xpert TB/RIF assay, and 4 had positive smear microscopy. Patients with pulmonary TB were more likely to use injection drugs (67% vs 36%, P = .02) and have a positive HCV antibody (73% vs 42%, P = .02). The presence and absence of any TB symptom had a sensitivity and negative predictive value for TB of 93% and 98%, respectively.

Conclusion

Our findings highlight the high prevalence of TB among newly diagnosed HIV-infected patients in an area with high rates of drug-resistant TB and the utility of an active case finding strategy for TB diagnosis.

Treatment Complexities Among Patients with Tuberculosis in a High HIV Prevalence Cohort in the United States

The association between human immunodeficiency virus (HIV) infection and tuberculosis (TB) mortality has been studied extensively, but the impact of HIV on other clinically relevant aspects of TB care such as TB drug-related adverse events (AEs), hospital readmissions, and TB treatment duration is less well characterized. We describe the association of HIV infection with TB clinical complexities and outcomes in a high HIV prevalence cohort in the United States. This is a retrospective cohort study among patients treated for culture-confirmed TB between 2008 and 2015 at an inner-city hospital in Atlanta, GA. Univariate analysis was used to estimate association of HIV with TB treatment interruption due to AEs, hospital readmissions, and treatment duration. Final unfavorable TB treatment outcome was defined as death, loss to follow-up, or recurrent TB. Logistic regression modeling was used to estimate association of HIV with final unfavorable outcomes. Among 274 patients with TB, 96 (35%) had HIV coinfection. HIV-positive patients had more TB treatment interruptions due to AE (34% vs. 15%), were more likely to have a hospital readmission (50% vs. 21%), and received longer TB treatment (9.9 months vs. 8.8 months) compared to HIV-negative patients (p < .01 for all). HIV infection was not associated with final unfavorable outcomes in univariate [odds ratio (OR) = 1.86; confidence interval (95% CI) 0.99-3.49] or multivariate analysis (aOR = 1.13; 95% CI 0.52-2.39) (p ≥ .05 for both). While HIV infection was not associated with final unfavorable TB outcomes, TB/HIV coinfected patients had more complex treatment course underscoring the importance of maintaining resources and expertise to treat coinfected patients in our and similar settings.

1020. Injection Drug Use-Associated Staphylococcus aureus Bacteremia in a Large Urban Hospital in Atlanta, Georgia

Background

Infectious complications of injection drug use (IDU) have increased with the expanding opioid epidemic in the southeast. We assessed the incidence, clinical presentation, and treatment outcomes of IDU-associated Staphylococcus aureus (SA) bacteremia (SAB).

Methods

We created a retrospective cohort of all adults with community acquired (CA) SAB over 5 years presenting to Grady Memorial Hospital, a 1,000-bed urban county hospital in Atlanta, GA. Charts were reviewed by infectious diseases physicians to obtain clinical and laboratory characteristics, including substance use disorder (SUD), and determine if SAB was IDU-associated. The study period was divided into three periods (P1 = March 2012–January 2014, P2 = January 2014–December 2015, P3 = December 2015–November 2017) to evaluate changes in the incidence of IDU-SAB over time using Poisson regression.

Results

Among 321 patients with a first episode of CA-SAB, 24 (7%) were IDU-SAB. The number of IDU-SAB cases in each period increased (P1 = 4, P2 = 7, and P3 = 13 [P = 0.07 for trend]). The median age of IDU-SAB patients was 38 (IQR 31–57), 11 (46%) were black, and 15 (63%) had chronic hepatitis C virus infection. Heroin was the most common injected drug (92%) followed by cocaine (25%); multiple drugs were injected in 29%. All but two patients (92%) had a complication of SAB, most commonly endocarditis (50%) and septic pulmonary emboli (38%). The median hospitalization was 23 days (IQR 19.5–37.5) and 5 patients (12%) left the hospital against medical advice (AMA). Readmission for persistent or recurrent SA infection during the study period was common (42%), and three (13%) died ≤6 months from initial presentation, including two with prior discharge AMA. Half of the discharge summaries did not mention SUD as a hospital problem. Outpatient SUD treatment was recommended to eight (33%) patients and a recommendation of abstinence was the intervention for 12 (50%).

Conclusion

Increasing IDU-SAB was observed over 5 years in our urban Atlanta hospital, primarily due to heroin use. Most cases were associated with complications of SAB with a long length of stay and frequent readmission, but few patients received treatment or harm reduction interventions for their SUD. These data will raise awareness and direct resources to expanding evidence-based opioid use disorder treatment for patients with infectious complications of IDU.

Disclosures

All authors: No reported disclosures.

Internal Medicine Residents' Knowledge and Practice of Pulmonary Tuberculosis Diagnosis

Background

Internal medicine physicians are often the first providers to encounter patients with a new diagnosis of tuberculosis. Given the public health risks of missed tuberculosis cases, assessing internal medicine residents’ ability to diagnose tuberculosis is important.

Methods

Internal medicine resident knowledge and practice patterns in pulmonary tuberculosis diagnosis at 7 academic hospitals were assessed utilizing (a) a 10-item validated pulmonary tuberculosis diagnosis assessment tool and (b) a retrospective chart review of 343 patients who underwent a pulmonary tuberculosis evaluation while admitted to a resident-staffed internal medicine or infectious disease service. Our primary outcomes were the mean score and percentage of correct responses per assessment tool question, and the percentage of patients who had Centers for Disease Control and Prevention–recommended tuberculosis diagnostic tests obtained.

Results

Of the 886 residents who received the assessment, 541 responded, yielding a response rate of 61%. The mean score on the assessment tool (SD) was 4.4 (1.6), and the correct response rate was 57% (311/541) or less on 9 of 10 questions. On chart review, each recommended test was obtained for ≤43% (148/343) of patients, other than chest x-ray (328/343; 96%). A nucleic acid amplification test was obtained for 18% (62/343) of patients, whereas 24% (83/343) had only 1 respiratory sample obtained. Twenty patients were diagnosed with tuberculosis.

Conclusions

Significant knowledge and practice gaps exist in internal medicine residents’ abilities to diagnose tuberculosis. As residents represent the future providers who will be evaluating patients with possible tuberculosis, such deficiencies must be addressed.

Challenges Across the HIV Care Continuum for Patients With HIV/TB Co-infection in Atlanta, GA [corrected]

Background

Antiretroviral therapy (ART) for persons with HIV infection prevents tuberculosis (TB) disease. Additionally, sequential ART after initiation of TB treatment improves outcomes. We examined ART use, retention in care, and viral suppression (VS) before, during, and 3 years following TB treatment for an inner-city cohort in the United States.

Methods

Retrospective cohort study among persons treated for culture-confirmed TB between 2008 and 2015 at an inner-city hospital.

Results

Among 274 persons with culture-confirmed TB, 96 (35%) had HIV co-infection, including 23 (24%) new HIV diagnoses and 73 (76%) previous diagnoses. Among those with known HIV prior to TB, the median time of known HIV was 6 years, and only 10 (14%) were on ART at the time of TB diagnosis. The median CD4 at TB diagnosis was 87 cells/uL. Seventy-four (81%) patients received ART during treatment for TB, and 47 (52%) has VS at the end of TB treatment. Only 32% of patients had continuous VS 3 years after completing TB treatment. There were 3 TB recurrences and 3 deaths post–TB treatment; none of these patients had retention or VS after TB treatment.

Conclusions

Among persons with active TB co-infected with HIV, we found that the majority had known HIV and were not on ART prior to TB diagnosis, and retention in care and VS post–TB treatment were very low. Strengthening the HIV care continuum is needed to improve HIV outcomes and further reduce rates of active TB/HIV co-infection in our and similar settings.

Time to Sputum Culture Conversion and Treatment Outcomes Among Patients with Isoniazid-Resistant Tuberculosis in Atlanta, Georgia

BACKGROUND

Although isoniazid-resistant tuberculosis is more common than multidrug-resistant tuberculosis, it has been much less studied. We examined the impact of isoniazid resistance and treatment regimen, including use of a fluoroquinolone, on clinical outcomes.

METHODS

A retrospective cohort study among patients with sputum culture-positive tuberculosis was performed. Early fluoroquinolone (FQ) use was defined as receiving ≥5 doses during the first month of treatment. The primary outcome was time to sputum culture conversion (tSCC). A multivariate proportional hazards model was used to determine the association of isoniazid resistance with tSCC.

RESULTS

Among 236 patients with pulmonary tuberculosis, 59 (25%) had isoniazid resistance. The median tSCC was similar for isoniazid-resistant and -susceptible cases (35 vs 29 days; P = .39), and isoniazid resistance was not associated with tSCC in multivariate analysis (adjusted hazard ratio = 0.83; 95% confidence interval [CI], .59-1.17). Early FQ use was higher in isoniazid-resistant than -susceptible cases (20% vs 10%; P = .05); however, it was not significantly associated with tSCC in univariate analysis (hazard ratio = 1.48; 95% CI, .95-2.28). Patients with isoniazid-resistant tuberculosis were treated with regimens containing rifampin, pyrazinamide, and ethambutol +/- a FQ for a median of 9.7 months. Overall, 191 (83%) patients were cured. There was no difference in initial treatment outcomes; however, all cases of acquired-drug resistance (n = 1) and recurrence (n = 3) occurred among patients with isoniazid-resistant tuberculosis.

CONCLUSIONS

There was no significant association with isoniazid resistance and tSCC or initial treatment outcomes. Although patients with isoniazid-resistant tuberculosis had a high cure rate, the cases of recurrence and acquired drug resistance are concerning and highlight the need for longer-term follow-up studies.

Unusual presentation of chikungunya virus infection with concomintant erysipelas in a returning traveler from the Caribbean: a case report

Chikungunya fever is a mosquito-borne febrile illness caused by Chikungunya virus (CHIKV), an alphavirus from the Togaviridae family. It is transmitted by primarily Aedes aegytpi and Aedes albopictus mosquitos [1]. Once of little importance in the Americas, local transmission was identified in the Caribbean in late 2013. More than 1000 travelers returning to the continental United States have been diagnosed with CHIKV. More importantly, there have been 9 documented cases of autochthonous disease in Florida as of September 16, 2014 [2].

New chemical method of viral inactivation for vaccine development based on membrane fusion inhibition

Membrane fusion is an essential step in the entry of enveloped viruses into their host cells. This process is triggered by conformational changes in viral surface glycoproteins. We have demonstrated previously that modification of vesicular stomatitis virus (VSV) with diethylpyrocarbonate (DEPC) abolished the conformational changes on VSV glycoprotein and the fusion reaction induced by the virus. Moreover, we observed that viral treatment with DEPC inactivates the virus, preserving the conformational integrity of its surface proteins. In the present work, we evaluated the potential use of DEPC as a viral inactivating chemical agent for the development of useful vaccines. Pathogenicity and viral replication in Balb/c mice were abolished by viral treatment with 0.5mM DEPC. In addition, antibodies elicited in mice after intraperitoneal immunization with DEPC-inactivated VSV mixed with adjuvants were able to recognize and neutralize the native virus and efficiently protected animals against the challenge with lethal doses of VSV. These results together suggest that viral inactivation with DEPC seems to be a suitable method for the development of safe vaccines.

Inactivation of vesicular stomatitis virus through inhibition of membrane fusion by chemical modification of the viral glycoprotein

Membrane fusion is an essential step in the entry of enveloped viruses into their host cells triggered by conformational changes in viral glycoproteins. We have demonstrated previously that modification of vesicular stomatitis virus (VSV) with diethylpyrocarbonate (DEPC) abolished conformational changes on VSV glycoprotein and the fusion reaction catalyzed by the virus. In the present study, we evaluated whether treatment with DEPC was able to inactivate the virus. Infectivity and viral replication were abolished by viral treatment with 0.5mM DEPC. Mortality profile and inflammatory response in the central nervous system indicated that G protein modification with DEPC eliminates the ability of the virus to cause disease. In addition, DEPC treatment did not alter the conformational integrity of surface proteins of inactivated VSV as demonstrated by transmission electron microscopy and competitive ELISA. Taken together, our results suggest a potential use of histidine (His) modification to the development of a new process of viral inactivation based on fusion inhibition.