Infectious Disease

Bispo PJM, Sahm DF, Asbell PA. A Systematic Review of Multi-decade Antibiotic Resistance Data for Ocular Bacterial Pathogens in the United States. Ophthalmol Ther 2022;11(2):503-520.Abstract
INTRODUCTION: Since 2009, the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study has been assessing in vitro antibiotic resistance for bacterial isolates sourced from ocular infections in the US. The main goal of this systematic review was to compare in vitro resistance data for ocular pathogens from published US studies with the most recently published data from the ARMOR study (2009-2018) and, where possible, to evaluate trends in bacterial resistance over time over all studies. METHODS: A literature search was conducted using MEDLINE®, BIOSIS Previews®, and EMBASE® databases (1/1/1995-6/30/2021). Data were extracted from relevant studies and antibiotic susceptibility rates for common ocular pathogens (Staphylococcus aureus, coagulase-negative staphylococci [CoNS], Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae), longitudinal changes in susceptibility, and multidrug resistance (MDR) were compared descriptively. RESULTS: Thirty-two relevant studies were identified. High in vitro resistance was found among S. aureus and CoNS to fluoroquinolones, macrolides, and methicillin/oxacillin across studies, with high rates of MDR noted, specifically among methicillin-resistant staphylococci. Data from studies pre-dating or overlapping the early years of ARMOR reflected increasing rates of S. aureus resistance to fluoroquinolones, macrolides, methicillin/oxacillin, and aminoglycosides, while the ARMOR data suggested slight decreases in resistance to these classes between 2009 and 2018. Overall, methicillin-resistant S. aureus (MRSA) prevalence peaked from 2005 to 2015 with a possible decreasing trend in more recent years. DISCUSSION AND CONCLUSIONS: Data from local and regional US datasets were generally consistent with data from the national ARMOR surveillance study. Continued surveillance of ocular bacterial pathogens is needed to track trends such as methicillin resistance and MDR prevalence and any new emerging antibiotic resistance phenotypes. Susceptibility data from ARMOR can inform initial choice of therapy, especially in practice areas where local antibiograms are unavailable.
Araujo-Alves AV, Kraychete GB, Gilmore MS, Barros EM, Giambiagi-deMarval M. shsA: A novel orthologous of sasX/sesI virulence genes is detected in Staphylococcus haemolyticus Brazilian strains. Infect Genet Evol 2022;97:105189.Abstract
The surface protein SasX, has a key role in methicillin-resistant Staphylococcus aureus (MRSA) colonization and pathogenesis, and has been associated with the epidemic success of some MRSA clones. To date, only one SasX homologous protein, named SesI, has been described in Staphylococcus epidermidis. In this work, we analyze the occurrence of the sasX gene and its genetic environment in Staphylococcus haemolyticus S. haemolyticus clinical strains (n = 62) were screened for the presence of the sasX gene and its carrier, the prophage Φ SPβ-like. A deep characterization was done in one strain (MD43), through which we determined the complete nucleotide sequence for the S. haemolitycus sasX-like gene. Whole genome sequencing of strain MD43 was performed, and the gene, termed here because of its unique attributes, shsA, was mapped to the Φ SPβ-like prophage sequence. The shsA gene was detected in 33 out of 62 strains showing an average identity of 92 and 96% with the sasX and sesI genes and at the amino acid level, 88% identity with SasX and 92% identity with SesI. The ~124Kb Φ SPβ-like prophage sequence showed a largely intact prophage compared to its counterpart in S. epidermidis strain RP62A, including the sesI insertion site. In conclusion, we identified a new sasX ortholog in S. haemolyticus (shsA). Its horizontal spread from this reservoir could represent an emergent threat in healthcare facilities since so far, no S. aureus sasX+ strains have been reported in Brazil.
Singh RB, Das S, Chodosh J, Sharma N, Zegans ME, Kowalski RP, Jhanji V. Paradox of complex diversity: Challenges in the diagnosis and management of bacterial keratitis. Prog Retin Eye Res 2022;88:101028.Abstract
Bacterial keratitis continues to be one of the leading causes of corneal blindness in the developed as well as the developing world, despite swift progress since the dawn of the "anti-biotic era". Although, we have expeditiously developed our understanding about the different causative organisms and associated pathology leading to keratitis, extensive gaps in knowledge continue to dampen the efforts required for early and accurate diagnosis, and management in these patients, resulting in poor clinical outcomes. The ability of the causative bacteria to subdue the therapeutic challenge stems from their large genome encoding complex regulatory networks, variety of unique virulence factors, and rapid secretion of tissue damaging proteases and toxins. In this review article, we provide an overview of the established diagnostic techniques and therapeutics for keratitis caused by various bacteria. We extensively report the recent in-roads through novel tools for accurately diagnosing mono- and poly-bacterial corneal infections. Furthermore, we outline the recent progress by our groups and others in understanding the sub-cellular genomic changes that lead to antibiotic resistance in these organisms. Finally, we discuss in detail, the novel therapies and drug delivery systems in development for the efficacious management of bacterial keratitis.
Succar T, Beaver HA, Lee AG. Impact of COVID-19 pandemic on ophthalmology medical student teaching: educational innovations, challenges, and future directions. Surv Ophthalmol 2022;67(1):217-225.Abstract
Graduate medical education (GME) in ophthalmology has faced and overcome many challenges over the past years, and 2020 has been a game-changer. Although the severe acute respiratory syndrome coronavirus pandemic disrupted medical education globally, ophthalmic educators rapidly transformed their curricula to novel and effective virtual learning formats. Thus, while the COVID-19 outbreak has been one of the most significant challenges faced in the history of medical education, it has also provided an impetus to develop innovative teaching practices, bringing with it unprecedented success in allowing medical students to continue their education in ophthalmology despite these challenges. We review and appraise novel educational interventions implemented by various institutions in response to the COVID-19 pandemic, highlighting their effectiveness, challenges and proposing future directions beyond the pandemic. Many of these innovations will persist even after the end of the pandemic because they have proven that face-to-face learning is not required for all aspects of the ophthalmic GME curriculum. As ophthalmic educators harness the power of educational technology it is critical that their novel educational initiatives are incorporated into competency-based curricula with assessments mapped to the competencies. Future research should focus on evaluating the impact of this transformation to virtual learning environments on student performances as well as implementing longitudinal assessment strategies for clinical competence in workplace-based practice.
Marsiglia M, Chwalisz BK, Maher M. Neuroradiologic Imaging of Neurologic and Neuro-Ophthalmic Complications of Coronavirus-19 Infection. J Neuroophthalmol 2021;41(4):452-460.Abstract
BACKGROUND: To review the literature and provide a summary of COVID-19-related neurologic and neuro-ophthalmic complications. METHODS: The currently available literature was reviewed on PubMed and Google Scholar using the following keywords for searches: CNS, Neuro-Ophthalmology, COVID-19, SARS-CoV-2, coronavirus, optic neuritis, pseudotumor cerebri, Acute Disseminated Encephalomyelitis, posterior reversible encephalopathy syndrome (PRES), meningitis, encephalitis, acute necrotizing hemorrhagic encephalopathy, and Guillain-Barré and Miller Fisher syndromes. RESULTS: Neuroradiologic findings of neurologic and neuro-ophthalmologic complications in relationship to COVID-19 infection were reviewed. Afferent visual pathway-related disorders with relevant imaging manifestations included fundus nodules on MRI, papilledema and pseudotumor cerebri syndrome, optic neuritis, Acute Disseminated Encephalomyelitis, vascular injury with thromboembolism and infarct, leukoencephalopathy, gray matter hypoxic injury, hemorrhage, infectious meningitis/encephalitis, acute necrotizing hemorrhagic encephalopathy, and PRES. Efferent visual pathway-related complications with relevant imaging manifestations were also reviewed, including orbital abnormalities, cranial neuropathy, Guillain-Barré and Miller Fisher syndromes, and nystagmus and other eye movement abnormalities related to rhombencephalitis. CONCLUSION: COVID-19 can cause central and peripheral nervous system disease, including along both the afferent and efferent components of visual axis. Manifestations of disease and long-term sequela continue to be studied and described. Familiarity with the wide variety of neurologic, ophthalmic, and neuroradiologic presentations can promote prompt and appropriate treatment and continue building a framework to understand the underlying mechanism of disease.
Kuang L, Ross AE, Kanu LN, Romanowski EG, Kowalski RP, Kohane DS, Ciolino JB. A novel, sensitive, and widely accessible besifloxacin quantification method by HPLC-fluorescence: Application to an ocular pharmacokinetic study. J Chromatogr B Analyt Technol Biomed Life Sci 2021;1185:123010.Abstract
Besifloxacin has been embraced for the treatment of ocular bacterial infections. While LC-MS/MS has been used in investigating BSF pharmacokinetics, those costly instruments are not universally available and have complicated requirements for operation and maintenance. Additionally, pharmacokinetics of besifloxacin in dose-intense regimens are still unknown. Herein, a new quantification method was developed employing the widely accessible HPLC with fluorescence detection and applied to an ocular pharmacokinetic study with an intense regimen. Biosamples were pre-treated using protein precipitation. Chromatographic separation was achieved on a C18 column using mobile phase of 0.1% trifluoroacetic acid and acetonitrile. To address the weak fluorescence issue of besifloxacin, effects of detection parameters, elution pattern, pH of mobile phase, and reconstitution solvents were investigated. The method was fully validated per US-FDA guidelines and demonstrated precision (<13%), accuracy (91-112%), lower limit of quantification (5 ng/mL), linearity over clinically relevant concentrations (R2 > 0.999), matrix-effects (93-105%), recoveries (95-106%), and excellent selectivity. The method showed agreement with agar disk diffusion assays for in vitro screening and comparable in vivo performance to LC-MS/MS (Deming Regression, y = 1.010x + 0.123, r = 0.997; Bland-Altman analysis, mean difference was -6.3%; n = 21). Pharmacokinetic parameters suggested superior surface-retentive properties of besifloxacin. Maximum concentrations were 1412 ± 1910 and 0.15 ± 0.12 μg/mL; area under the curve was 1,637 and 1.08 µg·h/g; and half-life was 4.9 and 4.1 h; and pharmacokinetic-to-pharmacodynamic ratios were ≥ 409 and ≤ 17.8 against ocular pathogens in tears and aqueous humor, respectively. This readily available method is sensitive for biosamples and practical for routine use, facilitating besifloxacin therapy development.
Nathan A, Rossin EJ, Kaseke C, Park RJ, Khatri A, Koundakjian D, Urbach JM, Singh NK, Bashirova A, Tano-Menka R, Senjobe F, Waring MT, Piechocka-Trocha A, Garcia-Beltran WF, Iafrate JA, Naranbhai V, Carrington M, Walker BD, Gaiha GD. Structure-guided T cell vaccine design for SARS-CoV-2 variants and sarbecoviruses. Cell 2021;184(17):4401-4413.e10.Abstract
The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants that escape convalescent and vaccine-induced antibody responses has renewed focus on the development of broadly protective T-cell-based vaccines. Here, we apply structure-based network analysis and assessments of HLA class I peptide stability to define mutationally constrained CD8+ T cell epitopes across the SARS-CoV-2 proteome. Highly networked residues are conserved temporally among circulating variants and sarbecoviruses and disproportionately impair spike pseudotyped lentivirus infectivity when mutated. Evaluation of HLA class I stabilizing activity for 18 globally prevalent alleles identifies CD8+ T cell epitopes within highly networked regions with limited mutational frequencies in circulating SARS-CoV-2 variants and deep-sequenced primary isolates. Moreover, these epitopes elicit demonstrable CD8+ T cell reactivity in convalescent individuals but reduced recognition in recipients of mRNA-based vaccines. These data thereby elucidate key mutationally constrained regions and immunogenic epitopes in the SARS-CoV-2 proteome for a global T-cell-based vaccine against emerging variants and SARS-like coronaviruses.
Ung L, Chodosh J. Urgent unmet needs in the care of bacterial keratitis: An evidence-based synthesis. Ocul Surf 2021;Abstract
Bacterial corneal infections, or bacterial keratitis (BK), are ophthalmic emergencies that frequently lead to irreversible visual impairment. Though increasingly recognized as a major cause of global blindness, modern paradigms of evidence-based care in BK have remained at a diagnostic and therapeutic impasse for over half a century. Current standards of management - based on the collection of corneal cultures and the application of broad-spectrum topical antibiotics - are beset by important yet widely underrecognized limitations, including approximately 30% of all patients who will develop moderate to severe vision loss in the affected eye. Though recent advances have involved a more clearly defined role for adjunctive topical corticosteroids, and novel therapies such as corneal crosslinking, overall progress to improve patient and population-based outcomes remains incommensurate to the chronic morbidity caused by this disease. Recognizing that the care of BK is guided by the clinical axiom, "time equals vision", this chapter offers an evidence-based synthesis for the clinical management of these infections, underscoring critical unmet needs in disease prevention, diagnosis, and treatment.
Zabaleta N, Dai W, Bhatt U, Hérate C, Maisonnasse P, Chichester JA, Sanmiguel J, Estelien R, Michalson KT, Diop C, Maciorowski D, Dereuddre-Bosquet N, Cavarelli M, Gallouët A-S, Naninck T, Kahlaoui N, Lemaitre J, Qi W, Hudspeth E, Cucalon A, Dyer CD, Pampena BM, Knox JJ, LaRocque RC, Charles RC, Li D, Kim M, Sheridan A, Storm N, Johnson RI, Feldman J, Hauser BM, Contreras V, Marlin R, Tsong Fang RH, Chapon C, van der Werf S, Zinn E, Ryan A, Kobayashi DT, Chauhan R, McGlynn M, Ryan ET, Schmidt AG, Price B, Honko A, Griffiths A, Yaghmour S, Hodge R, Betts MR, Freeman MW, Wilson JM, Le Grand R, Vandenberghe LH. An AAV-based, room-temperature-stable, single-dose COVID-19 vaccine provides durable immunogenicity and protection in non-human primates. Cell Host Microbe 2021;29(9):1437-1453.e8.Abstract
The SARS-CoV-2 pandemic has affected more than 185 million people worldwide resulting in over 4 million deaths. To contain the pandemic, there is a continued need for safe vaccines that provide durable protection at low and scalable doses and can be deployed easily. Here, AAVCOVID-1, an adeno-associated viral (AAV), spike-gene-based vaccine candidate demonstrates potent immunogenicity in mouse and non-human primates following a single injection and confers complete protection from SARS-CoV-2 challenge in macaques. Peak neutralizing antibody titers are sustained at 1 year and complemented by functional memory T cell responses. The AAVCOVID vector has no relevant pre-existing immunity in humans and does not elicit cross-reactivity to common AAVs used in gene therapy. Vector genome persistence and expression wanes following injection. The single low-dose requirement, high-yield manufacturability, and 1-month stability for storage at room temperature may make this technology well suited to support effective immunization campaigns for emerging pathogens on a global scale.
Song A, Deshmukh R, Lin H, Ang M, Mehta JS, Chodosh J, Said DG, Dua HS, Ting DSJ. Post-keratoplasty Infectious Keratitis: Epidemiology, Risk Factors, Management, and Outcomes. Front Med (Lausanne) 2021;8:707242.Abstract
Post-keratoplasty infectious keratitis (PKIK) represents a unique clinical entity that often poses significant diagnostic and therapeutic challenges. It carries a high risk of serious complications such as graft rejection and failure, and less commonly endophthalmitis. Topical corticosteroids are often required to reduce the risk of graft rejection but their use in PKIK may act as a double-edged sword, particularly in fungal infection. The increased uptake in lamellar keratoplasty in the recent years has also led to complications such as graft-host interface infectious keratitis (IIK), which is particularly difficult to manage. The reported incidence of PKIK differs considerably across different countries, with a higher incidence observed in developing countries (9.2-11.9%) than developed countries (0.02-7.9%). Common risk factors for PKIK include the use of topical corticosteroids, suture-related problems, ocular surface diseases and previous corneal infection. PKIK after penetrating keratoplasty or (deep) anterior lamellar keratoplasty is most commonly caused by ocular surface commensals, particularly Gramme-positive bacteria, whereas PKIK after endothelial keratoplasty is usually caused by Candida spp. Empirical broad-spectrum antimicrobial treatment is the mainstay of treatment for both PKIK, though surgical interventions are required in medically refractory cases (during the acute phase) and those affected by visually significant scarring (during the late phase). In this paper, we aim to provide a comprehensive overview on PKIK, encompassing the epidemiology, risk factors, causes, management and outcomes, and to propose a treatment algorithm for systematically managing this challenging condition.
Kaseke C, Park RJ, Singh NK, Koundakjian D, Bashirova A, Garcia Beltran WF, Takou Mbah OC, Ma J, Senjobe F, Urbach JM, Nathan A, Rossin EJ, Tano-Menka R, Khatri A, Piechocka-Trocha A, Waring MT, Birnbaum ME, Baker BM, Carrington M, Walker BD, Gaiha GD. HLA class-I-peptide stability mediates CD8+ T cell immunodominance hierarchies and facilitates HLA-associated immune control of HIV. Cell Rep 2021;36(2):109378.Abstract
Defining factors that govern CD8+ T cell immunodominance is critical for the rational design of vaccines for viral pathogens. Here, we assess the contribution of human leukocyte antigen (HLA) class-I-peptide stability for 186 optimal HIV epitopes across 18 HLA alleles using transporter associated with antigen processing (TAP)-deficient mono-allelic HLA-expressing cell lines. We find that immunodominant HIV epitopes increase surface stabilization of HLA class-I molecules in comparison to subdominant epitopes. HLA class-I-peptide stability is also strongly correlated with overall immunodominance hierarchies, particularly for epitopes from high-abundance proteins (e.g., Gag). Moreover, HLA alleles associated with HIV protection are preferentially stabilized by epitopes derived from topologically important viral regions at a greater frequency than neutral and risk alleles. These findings indicate that relative stabilization of HLA class-I is a key factor for CD8+ T cell epitope immunodominance hierarchies, with implications for HIV control and the design of T-cell-based vaccines.
Ou J, Zhou Z, Dai R, Zhang J, Zhao S, Wu X, Lan W, Ren Y, Cui L, Lan Q, Lu L, Seto D, Chodosh J, Wu J, Zhang G, Zhang Q. V367F Mutation in SARS-CoV-2 Spike RBD Emerging during the Early Transmission Phase Enhances Viral Infectivity through Increased Human ACE2 Receptor Binding Affinity. J Virol 2021;95(16):e0061721.Abstract
The current pandemic of COVID-19 is caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 spike protein receptor-binding domain (RBD) is the critical determinant of viral tropism and infectivity. To investigate whether naturally occurring RBD mutations during the early transmission phase have altered the receptor binding affinity and infectivity, we first analyzed in silico the binding dynamics between SARS-CoV-2 RBD mutants and the human angiotensin-converting enzyme 2 (ACE2) receptor. Among 32,123 genomes of SARS-CoV-2 isolates (December 2019 through March 2020), 302 nonsynonymous RBD mutants were identified and clustered into 96 mutant types. The six dominant mutations were analyzed applying molecular dynamics simulations (MDS). The mutant type V367F continuously circulating worldwide displayed higher binding affinity to human ACE2 due to the enhanced structural stabilization of the RBD beta-sheet scaffold. The MDS also indicated that it would be difficult for bat SARS-like CoV to infect humans. However, the pangolin CoV is potentially infectious to humans. The increased infectivity of V367 mutants was further validated by performing receptor-ligand binding enzyme-linked immunosorbent assay (ELISA), surface plasmon resonance, and pseudotyped virus assays. Phylogenetic analysis of the genomes of V367F mutants showed that during the early transmission phase, most V367F mutants clustered more closely with the SARS-CoV-2 prototype strain than the dual-mutation variants (V367F+D614G), which may derivate from recombination. The analysis of critical RBD mutations provides further insights into the evolutionary trajectory of early SARS-CoV-2 variants of zoonotic origin under negative selection pressure and supports the continuing surveillance of spike mutations to aid in the development of new COVID-19 drugs and vaccines. IMPORTANCE A novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused the pandemic of COVID-19. The origin of SARS-CoV-2 was associated with zoonotic infections. The spike protein receptor-binding domain (RBD) is identified as the critical determinant of viral tropism and infectivity. Thus, whether mutations in the RBD of the circulating SARS-CoV-2 isolates have altered the receptor binding affinity and made them more infectious has been the research hot spot. Given that SARS-CoV-2 is a novel coronavirus, the significance of our research is in identifying and validating the RBD mutant types emerging during the early transmission phase and increasing human angiotensin-converting enzyme 2 (ACE2) receptor binding affinity and infectivity. Our study provides insights into the evolutionary trajectory of early SARS-CoV-2 variants of zoonotic origin. The continuing surveillance of RBD mutations with increased human ACE2 affinity in human or other animals is critical to the development of new COVID-19 drugs and vaccines against these variants during the sustained COVID-19 pandemic.
Than T, Morettin CE, Harthan JS, Hartwick ATE, Huecker JB, Johnson SD, Migneco MK, Shorter E, Whiteside M, Margolis MS, Olson CK, Alferez CS, van Zyl T, Rodic-Polic B, Storch GA, Gordon MO. Efficacy of a Single Administration of 5% Povidone-Iodine in the Treatment of Adenoviral Conjunctivitis. Am J Ophthalmol 2021;Abstract
PURPOSE: To evaluate the safety and efficacy of a single, in-office administration of 5% povidone-iodine (PVP-I) compared to artificial tears (AT) for adenoviral conjunctivitis (Ad-Cs). DESIGN: Double-masked pilot randomized trial METHODS: Patients presenting with presumed adenoviral conjunctivitis were screened at 9 U.S. clinics. INCLUSION CRITERIA: ≥ 18 years of age, symptoms ≤ 4 days and a positive AdenoPlus® test. EXCLUSION CRITERIA: thyroid disease, iodine allergy, recent ocular surgery, and ocular findings inconsistent with early-stage Ad-Cs. Randomization was to a single administration of 5% PVP-I or AT in one eye and examinations on days 1-2, 4, 7, 14 and 21 with conjunctival swabs taken each visit for quantitative polymerase chain reaction. Primary outcome was percent reduction from peak viral load. Secondary outcomes were improvement in clinical signs and symptoms. RESULTS: Of 56 patients randomized, 28 had detectable viral titers at baseline. Day 4 post-treatment, viral titers in the 5% PVP-I and AT groups were 2.5% ± 2.7% and 14.4% ± 10.5% of peak respectively (p=0.020). Severity of participant-reported tearing, lid swelling and redness as well as clinician-graded mucoid discharge, bulbar redness and bulbar edema were lower in the 5% PVP-I group than AT group on Day 4 (p< 0.05). After Day 4, viral titers, severity of signs and symptoms decreased markedly in both groups and no differences between groups were detected. CONCLUSIONS: Pilot data suggest a single, in-office administration of 5% PVP-I could reduce viral load and hasten improvement of clinical signs and symptoms in patients with Ad-Cs.

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