Search

Objectives: Bacteriophage (phage) therapy is a promising anti-infective option to combat antimicrobial resistance. However, the clinical utilization of phage therapy has been severely compromised by the potential emergence of phage resistance. Although certain phage resistance mechanisms can restore bacterial susceptibility to certain antibiotics, a lack of knowledge of phage resistance mechanisms hinders optimal use of phages and their combination with antibiotics., Methods: Genome-wide transposon screening was performed with a mutant library of Klebsiella pneumoniae MKP103 to identify phage pKMKP103_1-resistant mutants. Phage-resistant phenotypes were evaluated by time-kill kinetics and efficiency of plating assays. Phage resistance mechanisms were investigated with adsorption, one-step growth, and mutation frequency assays. Antibiotic susceptibility was determined with broth microdilution and population analysis profiles., Results: We observed a repertoire of phage resistance mechanisms in K pneumoniae, such as disruption of phage binding (fhuA::Tn and tonB::Tn), extension of the phage latent period (mnmE::Tn and rpoN::Tn), and increased mutation frequency (mutS::Tn and mutL::Tn). Notably, in contrast to the prevailing view that phage resistance re-sensitizes antibiotic-resistant bacteria, we observed a bidirectional steering effect on bacterial antibiotic susceptibility. Specifically, rpoN::Tn increased susceptibility to colistin while mutS::Tn and mutL::Tn increased resistance to rifampicin and colistin., Discussion: Our findings demonstrate that K pneumoniae employs multiple strategies to overcome phage infection, which may result in enhanced or reduced antibiotic susceptibility. Mechanism-guided phage steering should be incorporated into phage therapy to better inform clinical decisions on phage-antibiotic combinations., (Copyright © 2024 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Broad spectrum oral antivirals are urgently needed for the early treatment of many RNA viruses of clinical concern. We previously described the synthesis of 1-O-octadecyl-2-O-benzyl-glycero-3-phospho-RVn (V2043), an orally bioavailable lipid prodrug of remdesivir nucleoside (RVn, GS-441524) with broad spectrum antiviral activity against viruses with pandemic potential. Here we compared the relative activity of V2043 with new RVn lipid prodrugs containing sn-1 alkyl ether or sn-2 glycerol modifications. We found that 3-F-4-MeO-Bn, 3-CN-Bn, and 4-CN-Bn sn-2 glycerol modifications improved antiviral activity compared to V2043 when tested in vitro against clinically important RNA viruses from 5 virus families. These results support the continued development of V2043 and sn-2 glycerol modified RVn lipid prodrugs for the treatment of a broad range of RNA viruses for which there are limited therapies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Objectives: Pan-drug-resistant (PDR) Pseudomonas aeruginosa is one of the three top-priority pathogens identified by the WHO, and bacteriophages have been investigated as an alternative therapy. However, knowledge on the pharmacokinetics/pharmacodynamics (PK/PD) of phage therapy is sparse, limiting its clinical applications. This study aimed to evaluate the PK/PD of the antipseudomonal phage øPEV20 in vivo following intravenous administration., Methods: Healthy Sprague-Dawley rats were given øPEV20 as a single intravenous bolus of ~6, 9 and 11-log 10 PFU/rat. Arterial blood was sampled over 72 h. At 72 h, the animals were killed and multiple tissues were harvested for biodistribution studies. A PK model was developed using the importance sampling algorithm and deterministic simulations with a PD model were performed., Results: A three-compartment model with non-linear clearance described the exposure of øPEV20 in blood. Model evaluation indicated that the model was robust and parameter estimates were accurate. The median (standard error) values of model-predicted PK parameters for V C , V P1 , V P2 , Q 1 , Q 2 , V m and K m were 111 mL/rat (8.5%), 128 mL/rat (4.97%), 180 mL/rat (4.59%), 30.4 mL/h/rat (19.2%), 538 mL/h/rat (4.97%), 4.39 × 10 10  PFU/h/rat (10.2%) and 1.64 × 10 7  PFU/mL/rat (3.6%), respectively. The distribution of øPEV20 was not homogeneous; there was preferential accumulation in the liver and spleen. Deterministic simulations with a PD model confirmed the importance of the host immune system in facilitating phage-mediated bacterial elimination., Conclusions: We developed a robust PK model to describe the disposition of phages in healthy rats. This model may have significant potential in facilitating future preclinical and clinical PK/PD investigations., (Copyright © 2020 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Pre-exposure prophylaxis (PrEP) with topically or systemically administered antiretroviral agents can prevent acquisition of human immunodeficiency virus type 1 (HIV-1) infection. However, in clinical trials using tenofovir-containing agents, HIV-1 acquisition is reduced but not eliminated. Incomplete adherence remains the major contributor to failure. Sustained release or long-acting antiretroviral agents may provide better HIV-1 protection by reducing the clinical impact of incomplete adherence. To reduce dosing frequency, we synthesized a novel tenofovir prodrug, octadecyloxyethyl benzyl tenofovir (ODE-Bn-TFV), that is designed to release TFV slowly in tissues, and showed potent anti-HIV activity in vitro (EC 50  = 1.7 nM). In cells exposed to 14 C labeled TFV, ODE-Bn-TFV or the quickly activated monoester ODE-TFV, rapid cellular uptake for both lipophilic analogs was noted, achieving 50-fold higher levels than unmodified TFV after 48 h. Following exposure to ODE-[8- 14 C]TFV, the intracellular diphosphate levels were approximately four-fold higher than with ODE-Bn-TFV. However, intracellular TFVpp drug levels fell rapidly yielding a half-life of about two days. TFVpp levels in ODE-Bn-TFV treated cells decreased much more slowly and reached half-maximal levels in about seven days. These results suggest early accumulation of ODE-Bn-TFV followed by sustained intracellular release following cleavage of the ester bonds linking the ODE and benzyl moieties to the active molecular precursor, thereby potentially allowing for less frequent administration than with more rapidly activated forms of tenofovir., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Bacteriophage therapy (BT) uses bacteriophages to treat pathogenic bacteria and is an emerging strategy against multidrug-resistant (MDR) infections. Experience in solid organ transplant is limited. We describe BT in 3 lung transplant recipients (LTR) with life-threatening MDR infections caused by Pseudomonas aeruginosa (n = 2) and Burkholderia dolosa (n = 1). For each patient, lytic bacteriophages were selected against their bacterial isolates. BT was administered for variable durations under emergency Investigational New Drug applications and with patient informed consent. Safety was assessed using clinical/laboratory parameters and observed clinical improvements described, as appropriate. All patients received concurrent antibiotics. Two ventilator-dependent LTR with large airway complications and refractory MDR P. aeruginosa pneumonia received BT. Both responded clinically and were discharged from the hospital off ventilator support. A third patient had recurrent B. dolosa infection following transplant. Following BT initiation, consolidative opacities improved and ventilator weaning was begun. However, infection relapsed on BT and the patient died. No BT-related adverse events were identified in the 3 cases. BT was well tolerated and associated with clinical improvement in LTRs with MDR bacterial infection not responsive to antibiotics alone. BT may be a viable adjunct to antibiotics for patients with MDR infections., (© 2019 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Objectives: The prevalence of vitamin D insufficiency in Africans with AIDS-associated Kaposi sarcoma (AIDS-KS) and the role of vitamin D in AIDS-KS progression are unknown. We hypothesized that a high prevalence of vitamin D deficiency would be found in Zimbabweans with AIDS-KS and that low baseline vitamin D would correlate with progression of AIDS-KS., Methods: Ninety subjects were enrolled in a prospective pilot study investigation of the effect of antiretroviral therapy in the treatment of AIDS-KS in Harare, Zimbabwe. Co-formulated abacavir, lamivudine, and zidovudine was initiated; chemotherapy was provided at the discretion of the provider. Participants were followed for 96 weeks. 25-Hydroxyvitamin D was measured in stored specimens collected at study entry. The relationship between vitamin D and clinical response was described by odds ratio and 95% confidence interval., Results: Samples were available for 85 participants; 45 (53%) subjects had inadequate (<75 nmol/l) 25-hydroxyvitamin D. HIV-1 RNA was significantly higher among those with insufficient vitamin D (4.7 vs. 4.5 log, p = 0.04). Tumor response, survival, and KS-IRIS were not associated with vitamin D (p ≥ 0.3)., Conclusions: Vitamin D insufficiency was common among Zimbabweans with AIDS-KS but not associated with outcomes after initiation of antiretroviral therapy., (Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.)

An influenza pandemic poses a serious threat to humans and animals. Conventional treatments against influenza include two classes of pathogen-targeting antivirals: M2 ion channel blockers (such as amantadine) and neuraminidase inhibitors (such as oseltamivir). Examination of the mechanism of influenza viral infection has shown that endosomal acidification plays a major role in facilitating the fusion between viral and endosomal membranes. This pathway has led to investigations on vacuolar ATPase (v-ATPase) activity, whose role as a regulating factor on influenza virus replication has been verified in extensive genome-wide screenings. Blocking v-ATPase activity thus presents the opportunity to interfere with influenza viral infection by preventing the pH-dependent membrane fusion between endosomes and virions. This study aims to apply diphyllin, a natural compound shown to be as a novel v-ATPase inhibitor, as a potential antiviral for various influenza virus strains using cell-based assays. The results show that diphyllin alters cellular susceptibility to influenza viruses through the inhibition of endosomal acidification, thus interfering with downstream virus replication, including that of known drug-resistant strains. In addition, combinatorial treatment of the host-targeting diphyllin with pathogen-targeting therapeutics (oseltamivir and amantadine) demonstrates enhanced antiviral effects and cell protection in vitro., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The measurement of the absolute CD4 T-cell count is critical in the initial evaluation and staging of HIV-infected persons, yet access to this technology remains limited in many low resource settings where disease burden is highest. Here we evaluate the performance of a prototype point-of-care device (POC) to quantify CD4 T cells from MBio Diagnostics, Inc. Whole blood samples, both venous and capillary (finger stick), were collected from known HIV-infected participants at the University of California, San Diego Antiviral Research Center, and tested using the MBio system and conventional flow cytometry. A total of 94 venipuncture and 52 capillary samples were processed and statistical analyses included comparison to flow cytometry results. For the venipuncture samples, Bland-Altman analysis resulted in a mean bias of -10 cells/μL (-23 to +3 cells/μL, 95% CI), and limits of agreement (LOA) of -132 and +112 cells/μL. For the capillary samples, Bland-Altman resulted in a mean bias of -4 cells/μL (-31 to +23 cells/μL, 95% CL), and LOA of -195 and +186 cells/μL. For the San Diego study cohort, the prototype MBio system showed negligible quantitative bias relative to flow cytometry. Higher variability was observed in the capillary samples relative to venipuncture, but system precision for both capillary and venipuncture samples was good. There was also close agreement between results from the same participant when tested with two different systems, different operators and different locations. This preliminary evaluation suggests that the MBio CD4 device holds promise as a POC system for quantitation of CD4 T cells in limited-resource settings., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Genetic modification of hemopoietic progenitor cells ex vivo, followed by the infusion of the genetically modified cells into the human immunodeficiency virus-1 (HIV-1) infected donor, has been proposed as a treatment for HIV-1 infection. The current study was undertaken to evaluate the effect of hemopoietic stem cell mobilization and harvesting on HIV-1 replication in persons with HIV-1 infection. Eighteen HIV-1-infected persons received recombinant granulocyte colony-stimulating factor (G-CSF; Filgrastim) 10 microg/kg per day, for 7 days. On days 4 and 5, peripheral blood mononuclear cells were harvested by leukapheresis. The CD4+ lymphocyte count at entry was >500/microL for 6 subjects, 200 to 500/microL for 6 subjects, and <200/microL for 6 subjects. For 9 of 18 subjects, plasma HIV-1 RNA levels increased 4- to 100-fold (>0.6 log(10)) above baseline between days 4 and 7 and returned to baseline by day 27. Significant increases of plasma HIV-1 RNA levels occurred in 5 subjects despite 3-drug antiretroviral therapy. Changes in CD4+ and CD34+ cells during mobilization and harvesting were similar in all subjects whether they had or did not have increased plasma HIV-1 RNA levels. Thus, mobilization and harvesting of bone marrow progenitor cells from persons infected with HIV-1 induced a transient increase in viral replication in some patients but was not associated with adverse effects. (Blood. 2000;95: 48-55)

Although cytomegalovirus (CMV) is rarely cultured from peripheral-blood leukocytes of immunocompetent patients, it may be cultured from up to 60% of renal transplant recipients, 1 to 4 months after transplantation. During this same period, renal transplant recipients are often referred for psychiatric evaluation. Since CMV may infect the central nervous system, the relationship between isolation of CMV from peripheral-blood leukocytes (viremia) and psychiatric evaluation was investigated in 80 renal allograft recipients at the Massachusetts General Hospital. Five of 16 (31%) patients with viremia and 7 of 64 (11%) patients without viremia required psychiatric consultation (P = 0.04, two-tailed Fisher exact test). CMV viremia may be an important but treatable contributor to psychiatric symptoms in the transplant recipient.

Twenty-one patients with postherpetic neuralgia of two- to 84-months duration participated in a double-blind, placebo-controlled study of oral acyclovir. Pain perception was assessed with the Melzack Pain Questionnaire at baseline and at two-to six-week intervals during the ensuing six months. Clinically significant pain reduction occurred in eight patients: four received acyclovir, and four received a placebo. Several treatment strategies have been advocated for relief of postherpetic neuralgia. Results of the present study demonstrate the need for a double-blind, placebo-controlled paradigm to substantiate the efficacy of new clinical approaches. The same caveat applies to the more common syndromes encountered in psychiatric practice.

A distinctive glomerular lesion of renal allografts, acute allograft glomerulopathy (AAG), is characterized by hypercellularity and endothelial cell hypertrophy and injury. For elucidating the pathogenesis of this lesion, the infiltrating cells were analyzed by light- and electron-microscopic immunoperoxidase techniques with monoclonal antibodies and compared with those in cellular rejection without AAG (non-AAG). Substantial numbers of T lymphocytes (CD3+,Leu-4+) were detected in the glomeruli in AAG (11.4 +/- 2.4 cells per glomerular cross-section), whereas very few were found in non-AAG (1.4 +/- 1.8, P less than 0.001). In AAG the CD8+ (Leu-2a) subset accounted for essentially all of the intraglomerular T cells, which had a lower CD4/CD8 ratio than the corresponding peripheral blood lymphocytes (P less than 0.03). AAG also differed from non-AAG by the accumulation of intraglomerular mononuclear cells that expressed HNK-1 antigen (Leu-7) and mononuclear phagocytes, which were identified by the presence of the monocyte fibronectin receptor (A6F10). Intraglomerular mononuclear cells were positive for the interleukin-2 receptor (IL2R) and HLA Class II antigens (HLA-DR). The glomeruli in AAG stained more intensely for HLA Class I antigens than the tubules, in contrast to non-AAG cases (P less than 0.03). The interstitial infiltrates in AAG grafts were less intense than in non-AAG of similar duration (P less than 0.01) and had a lower CD4/CD8 ratio, whereas arterial intimal infiltrates were more severe in AAG (P less than 0.03) and consisted of CD8+, but not CD4+, cells. Pathologic features that correlated with poor graft survival were increased numbers of intraglomerular CD8+ cells (both AAG and non-AAG), fewer interstitial T cells (AAG), and more interstitial CD8+ cells (non-AAG) (all P less than 0.05). Cytomegalovirus (CMV) infection was detected in all (8/8) patients with AAG who were studied for infection before or within 3 weeks after the biopsy, compared with 3 of 9 patients with non-AAG. It is proposed that acute allograft glomerulopathy is a distinct form of T-cell-mediated allograft rejection, sometimes associated with CMV infection, in which the glomerular endothelium, often with the arterial endothelium, becomes the principal target of CD8+ T cells.

The human T-lymphotropic retrovirus type III (HTLV-III), the etiological agent of AIDS, has recently been detected in tears, cornea, and conjunctiva, raising the possibility of transmission of HTLV-III via contact lens trial sets used in routine fitting. We evaluated the ability of several contact lens cleaning solutions, with or without conditioning or disinfecting solutions, to disinfect contact lenses experimentally contaminated with HTLV-III. Following attempted disinfection, the lenses were cultured for residual HTLV-III on Hg cells for 28 days. Cultures without characteristic cytopathic effects, reverse transcriptase activity, and HTLV-III-specific antigen expression were considered negative. We found that all commercially available cleaning solutions tested were able to disinfect contact lenses exposed to HTLV-III.

Pompe's disease (acid maltase deficiency) classically affects infants and children, with a few sporadic cases occurring in adults. An adult patient initially have progressive muscular weakness, exertional dyspnea, diaphragmatic paralysis, and objective evidence of restrictive respiratory disease. Muscle biopsy established the diagnosis of acid maltase deficiency. The patient's brother had died at the age of 44 years, after 23 years of a "progressive muscular dystrophy." Acid maltase deficiency should be considered in the differential diagnosis of progressive respiratory insufficiency associated with weakness.

A system of 3H-thymidine incorporation by lymphocytes in culture for 3 wk has been utilized for quantitative assessment of the ability of T lymphocytes to inhibit outgrowth of autologous Epstein-Barr virus (EBV) transformed B lymphocytes. Lymphocytes from EBV-seronegative individuals lack the ability to suppress outgrowth of autologous EBV-transformed B lymphocytes. This capability appears during the course of primary EBV-induced infectious mononucleases (IM) as the atypical lymphocytosis is subsiding and persists for years after recovery from primary EBV infection. The ability of T lymphocytes from EBV-seropositive subjects or convalescent IM patients to inhibit B-lymphocyte outgrowth is not HLA restricted. Thus, T lymphocytes capable of inhibition of in vitro EBV-induced B-cell outgrowth emerge during the acute stage of IM and may represent an important control mechanism of EBV-induced B-lymphocyte proliferation in vivo. The system provides a highly sensitive quantitative means for in vitro assessment of cell-mediated immunity to EBV.

The T-lymphocyte subset interactions in the cell-mediated response to Epstein-Barr virus (EBV) were studied in an in vitro system in which the ability of T lymphocytes to inhibit outgrowth of autologous EBV-transformed B lymphocytes is assessed. Inhibition could be demonstrated within lymphocytes of both the T4 and T8 surface phenotypes. Outgrowth inhibition was observed more frequently when the effector T-cell population contained cells of both surface phenotypes. In blocking experiments the OKT3 antibody completely prevents development of outgrowth inhibitory activity; the OKT4 and OKT8 antibodies were less effective in interfering with outgrowth inhibitory function. Maximal blocking activity occurred when antibody addition occurred in the early phase of generation of suppressor function. Pharmacologically achievable concentrations of interferon-alpha restored outgrowth inhibitory activity after blocking with monoclonal antibody. EBV reactivation was easily demonstrable in a group of 10 renal allograft recipients who received OKT3 antibody for treatment of acute rejection. These studies suggest that the immunoregulatory control of proliferation of EBV-transformed B lymphocytes is complex, and involves a collaborative interaction of lymphocytes of both the T4 and T8 surface phenotypes.

Recombinant human interferon alfa-A (rIFN alpha A) had a dose-related suppressive effect on human T lymphotropic virus type III (HTLV-III) replication in vitro in normal peripheral-blood mononuclear cells (PBMC). Both single-dose and multiple-dose regimens were inhibitory. Such inhibitory concentrations (4-1024 units/ml) were not toxic to PBMC in culture, and were within the ranges achievable in blood after injection. These studies suggest that clinical trials of rIFN alpha A in early HTLV-III infection are warranted.

The idiopathic hypereosinophilic syndrome, a disorder characterized by peripheral blood and bone marrow eosinophilia associated with single or multiple organ system dysfunction attributable to tissue invasion by eosinophils has, in the past, been associated with an extremely poor prognosis. Recently, we reported the favorable impact of a therapeutic protocol consisting of prednisone and/or hydroxyurea on the morbidity and mortality of this syndrome. We have reviewed the clinical and hematologic features upon admission and the subsequent clinical courses of 32 patients with this disease referred to the NIH between 1965 and 1979 in an effort to determine which features suggest a more rapidly progressive course. A grading system based on 22 clinical features involving the 8 organ systems commonly affected by the illness was devised. The disease followed a more aggressive course in patients with evidence of cardiac or neurologic dysfunction at the time of initial NIH evaluation. Although splenomegaly, in and of itself, caused little morbidity, splenic enlargement at presentation appeared to be a predictor of a more aggressive course. The clinical grading system accurately predicted which patients would require no specific antihypereosinophilic therapy, which patients would respond adequately to corticosteroids, and which patients would require therapy with cytotoxic agents. It is proposed that this clinical grading system, and the hematologic grading system outlined in the accompanying report be used as aids in the selection of initial therapy in this group of patients.

A flow cytometric method for enumeration of intracytoplasmic antibody-containing cells was developed. Flow cytometry was found to yield results comparable to traditional fluorescence microscopy in cells stimulated to produce intracytoplasmic antibody by either pokeweed mitogen or Epstein-Barr virus. This technique offers several advantages over traditional fluorescence microscopy, including objective measurement of fluorescence intensity and rapid analysis of large numbers of cells.

A retrospective blind study of 32 patients with the hypereosinophilic syndrome was undertaken utilizing a hematologic scoring system that was based on peripheral blood and bone marrow findings, cytogenetics B12 levels, and leukocyte alkaline phosphatase determinations. In addition to the grading system, which allowed formulation of a hematologic score, the date could also be normalized for individuals who did not have all tests performed by use of the hematologic quotient. This study clearly defined two groups of patients within the idiopathic hypereosinophilic syndrome. One group were those individuals with low hematologic scores and quotients who did not require therapy or who responded to prednisone therapy, while the second group of patients required cytotoxic therapy. These patients had significantly higher hematologic scores and quotients and a significant number of abnormalities similar to those seen in myeloproliferative syndromes, such as myelofibrosis and cytogenetic abnormalities. This type of hematologic scoring seems useful in predicting therapy and/or evaluating individuals or groups of patients with the hypereosinophilic syndrome.

Cervical secretions from 14 women seropositive for HTLV-III/LAV were obtained between days 7 and 21 of the menstrual cycle and cultured for virus. HTLV-III/LAV was isolated from cervical secretions in 4 of 14 women, as well as from blood of 7 of 13 women tested. Female genital secretions may therefore be a source for sexual transmission of the virus to men.