Management of acyclovir-resistant herpes simplex virus

Antiviral Potential and Chemical Composition of Wild Baccharis crispa Spreng. Populations (Asteraceae) from Córdoba, Argentina: Perspective on Population Variability

Medicinal plants have been explored worldwide as potential alternatives for the prevention and treatment of different diseases, including viral infections. Baccharis crispa Spreng. (Asteraceae) is a native medicinal species widely used in South America. Given the influence of genetic and environmental factors on secondary metabolites biosynthesis and accumulation, this study aimed to evaluate the in vitro antiviral activity of four wild populations of B. crispa from Córdoba, Argentina, and assess the variability in their bioactivity and chemical composition. The cytotoxicity of chloroform, ethanol, and aqueous extracts from aerial parts was evaluated by the neutral red uptake method. Antiviral and virucidal activity against herpes simplex virus type 1 (HSV-1) and chikungunya virus (CHIKV) were assessed via plaque-forming unit (PFU) reduction assay. Phytochemical analyses of the extracts were conducted using HPLC-ESI- MS/MS. The Puesto Pedernera population showed the strongest antiviral activity, with inhibition rates of 82% for CHIKV and 79% against HSV-1, as well as potent virucidal effects, reducing PFU formation by up to 5 logarithms for both viruses. Remarkably, ethanol extract exhibited the least toxicity and strongest inhibitory activity. Villa del Parque population was inactive. We identified 38 secondary metabolites, predominantly phenolic acids (12) and flavonoids (18), in varying proportions. Delphinidin and delphinidin-3-glucoside are described for the first time in the species. Differences in phytochemical profiles were observed among extract types and populations. Key phenolic compounds showed moderate positive correlations with the evaluated bioactivities, emphasizing the complexity of phytochemical properties and interactions. These results highlight the therapeutic potential of B. crispa extracts against viral infections and underscore the importance of considering the geographical source of plant material in bioactivity evaluations.

An Insight into Current Treatment Strategies, Their Limitations, and Ongoing Developments in Vaccine Technologies against Herpes Simplex Infections

Herpes simplex virus (HSV) infection, the most prevalent viral infection that typically lasts for a lifetime, is associated with frequent outbreaks of oral and genital lesions. Oral herpes infection is mainly associated with HSV-1 through oral contact, while genital herpes originates due to HSV-2 and is categorized under sexually transmitted diseases. Immunocompromised patients and children are more prone to HSV infection. Over the years, various attempts have been made to find potential targets for the prevention of HSV infection. Despite the global distress caused by HSV infections, there are no licensed prophylactic and therapeutic vaccines available on the market against HSV. Nevertheless, there are numerous promising candidates in the pre-clinical and clinical stages of study. The present review gives an overview of two herpes viruses, their history, and life cycle, and different treatments adopted presently against HSV infections and their associated limitations. Majorly, the review covers the recent investigations being carried out globally regarding various vaccine strategies against oral and genital herpes virus infections, together with the recent and advanced nanotechnological approaches for vaccine development. Consequently, it gives an insight to researchers as well as people from the health sector about the challenges and upcoming solutions associated with treatment and vaccine development against HSV infections.

Evaluation of (S)-10-Hydroxycamptothecin Inhibitor of Herpes Simplex Type 1 Identified from Screening of a Library of Natural Products

Background: Herpes simplex virus type 1 (HSV-1) causes serious illness in humans, especially in newborns and immunocompromised hosts. Public health requires the development of new, less toxic anti-HSV-1 drugs. Objectives: This study aimed to evaluate the potential anti-herpesvirus activity of natural products in an extensive library of 133 compounds by examining viral titers and the number of viral plaques. Methods: (S)-10-hydroxycamptothecin (10-HCPT) as an inhibitor against viral DNA replication in the lowest concentration ranges from a set of natural products consisting of screening 133 compounds. Each step of the viral replication cycle of HSV-1 on A549 cells was evaluated with different assays, including adsorption, penetration, time-of-addition assay, and quantitative polymerase chain reaction (PCR). The respective antiviral effects on HSV-1AN95 infection were assessed in vitro. Results: 10-HCPT was found to be a potent inhibitor of HSV-1 infection in the lowest concentration range from screening of a natural product library. The results showed that 10-HCPT significantly affects HSV-1 viral plaque formation inhibition, with a half maximal effective concentration (EC50) of 0.07 μM. The time of addition assay suggested that 10-HCPT had a viral inhibitory effect when added 8 hours after infection. It was further confirmed by reducing the expression of late viral genes including glycoprotein (g) and viral protein (VP) (gB, gD, gH, VP1/2, and VP16) 4 hours after infection in the 10-HCPT treatment group compared to positive controls by quantitative real-time PCR. The Western blotting results are inconsistent with other reported results. It showed that 10-HCPT did not affect gD and ICP4 during HSV-1 infection, and 10-HCPT appeared to affect other genes in the immediate-early (IE) and late (L) steps. Conclusions: 10-HCPT demonstrated anti-HSV activity on HSV-1. Their dose-dependent antiviral activity showed that specific cellular components might mediate their function rather than cytotoxicity. This survey suggests a new outlook in exploring effective treatment options for HSV-1 infections.

Evaluating the therapeutic efficacy of triptolide and (S)-10-hydroxycamptothecin on cutaneous and ocular Herpes Simplex Virus type-1 infections in mice

Objective

The emergence of Acyclovir-Resistant Herpes Simplex Virus type-1, which is the result of clinical over usage calls for the urgent need of a novel anti-HSV agent. Hence, the activity of Triptolide (TP) and (S)-10-Hydroxycamptothecin (10-HCPT) were investigated as natural products in two infection models of HSV-1.

Methods

The antiviral efficacy of TP and 10-HCPT was evaluated in mice ocular and cutaneous infection models of HSV. Groups of 10 mice were infected with HSV-1. Both compounds were administered topically on corneal and skin. The disease severity, viral titer (plaque reduction assay), and histopathology were evaluated in the ocular and cutaneous models of HSV-1 infection on days 3, 5, 7, 9, and 12 post infection, as well as genome loads on days 3 and 12.

Results

Topical treatment of corneal with TP, 10-HCPT, and ACV was effective in reducing stromal disease (after day 3, P = 0.001), plus TP and ACV on vascularization (after day 7, P = 0.001). The virus titer decreased significantly in the infected treated groups after day 3 (P < 0.05). Also, on day 12 post-infection, the virus genome volume in the TP and ACV groups was significantly reduced. With respect to virus titers and the DNA yield, significant difference was observed, merely in the ACV group in comparison to the control (P = 0.013). Immunohistochemistry analysis showed that corneal epithelium healing was partially visible in the 10-HCPT group, which gradually increased in TP, and was the highest in the ACV group. The skin epithelium healing was only observed in TP and ACV groups, and was superior in the ACV group.

Conclusions

This study revealed the virologic and clinical potential of TP in-vivo to treat ocular mouse model.

Antiviral activity of triptolide on herpes simplex virus in vitro

BACKGROUND

Herpes simplex virus-type 1 (HSV-1) can cause diseases, especially amongst neonates and immunocompromised hosts. Hence, developing a novel anti-HSV-1 drug with low-level toxicity is vital. Triptolide (TP), a diterpenoid triepoxide is a natural product with range of bioactivity qualities.

METHODS

In this study, viral infection was assessed in different phases of the HSV-1 replication cycle on A549 cells, using various assays, such as adsorption inhibition assay, penetration inhibition assay, time-of-addition assay, and quantitative polymerase chain reaction (qPCR).

RESULTS

The results indicate that TP can effectively inhibit HSV-1 infection in the lowest range of concentration. TP exhibited significant inhibitory effect on HSV-1 plaque formation, with 50% effective concentration (EC50) of 0.05 µM. Furthermore, the time-of-addition assay suggests that TP has viral inhibitory effects when it was added less than 8 h postinfection (h.p.i.). This result is further confirmed by decline in the expression viral immediate-early genes (ICP4, ICP22, and ICP27) in 6 h.p.i in the TP-treated group compared to the control group, evaluated by real-time qPCR. The Western blotting result was also consistent with the previous findings, which confirms that TP can positively affect ICP4 during HSV-1 infection.

CONCLUSIONS

The TP also showed antiviral activity against HSV-1. This dose-dependent activity is an indication of a particular cellular component, rather than cytotoxicity that has mediated its function. Finally, the result suggest a new approach for an effective treatment option of the HSV-1 infections.

Prophylactic treatment with BX795 blocks activation of AKT and its downstream targets to protect vaginal keratinocytes and vaginal epithelium from HSV-2 infection

Genital herpes infections in humans are usually caused by herpes simplex virus type-2 (HSV-2), which result in recurrent lesions in the anogenital region. Past studies have shown that a viral protein translation inhibitor, BX795 is capable of mitigating HSV-2 infection both in vitro and in vivo when dosed therapeutically. However, any preventative benefits of this compound against HSV-2 infection remain poorly understood. In this study, we show that BX795 when added prophylactically to human vaginal keratinocytes generates strong preventative effects against a future HSV-2 infection. As a possible mechanism for this action, we found that BX795 efficiently reduces phosphorylation of AKT and its downstream targets p70S6K and 4EBP1. Our in-silico protein docking studies support our immunoblotting results and provide further credence to the proposed mechanism. Using a murine model of vaginal infection, we show that prior treatment with BX795 is also protective in vivo and leads to lower viral replication in the vaginal tissue.

Novel Insights to Enhance Therapeutics With Acyclovir in the Management of Herpes Simplex Encephalitis

Acyclovir is an antiviral drug poorly absorbed in the gastrointestinal tract due to its hydrophilicity, with low oral bioavailability (~20%). Although acyclovir is prescribed in the management of herpes simplex encephalitis (HSE), the disease has a poor prognosis, particularly if the treatment is delayed, reaching mortality rates of 70% if left untreated. Thus, high acyclovir doses are administered by intravenous (IV) infusion, usually at a dosage of 10 mg kg^-1 8-hourly in adults with normal renal function. However, the mortality related to HSE treated with acyclovir remains high (~20%) and permanent sequelae are commonly reported after 1 year (~50%). This review analyzed clinical trials following IV acyclovir administration. Novel insights aiming to improve drug bioavailability were reviewed, including acyclovir or its prodrugs, leading to the systemic distribution of the drug or drug targeting. Much research effort has been made to improve antiviral therapy, searching for delivery systems increasing acyclovir bioavailability by non-invasive pathways, such as oral and nasal pathways, or parenterally administered nanotechnology-based systems leading to drug targeting. Nanocarriers administered by non-invasive pathways represent feasible alternatives to treat HSE, even though not be industrially manufactured yet.

Cutaneous manifestations of B-cell chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a malignant lymphoproliferative disease characterized by the accumulation of immature monoclonal B lymphocytes in blood cells, bone marrow, spleen and lymph nodes. This is the most common type of leukemia among the Caucasoid race. When CLL skin lesions occur in about 25% of patients, they are extremely diverse. These lesions can be divided into specific, including infiltration of the skin by leukemic cells and the skin form of Richter's syndrome, secondary skin tumors, nonspecific lesions and associated skin diseases.Leukemic infiltration of the skin in patients with leukemia is called specific skin lesions (SSL). Many authors associate the unfavorable prognosis with the transformation of CLL with specific infiltration of the skin into Richter syndrome, as well as the appearance of SSL before the diagnosis of CLL. The risk of developing various cancer pathologies in patients with CLL is three times higher than in healthy people identical in sex and age. It was found that the risk of skin cancer in these patients is eight times higher than in the healthy population. The most common secondary skin tumors in CLL are basal-cell carcinoma, squamous-cell carcinoma, melanoma, and Merkel tumor.Nonspecific skin changes are extremely diverse and occur in patients with CLL in 30-50% of cases. The most common secondary changes in the skin in CLL are those of infectious nature. There are also increased reactions to insect bites, generalized itching, exfoliative erythroderma, nodular erythema, paraneoplastic pemphigoid, bullous pemphigoid, drug eruption. Concomitant dermatoses in these patients are more severe and often torpid to the previously conducted therapy. There is no doubt that together with the clarification of the etiology and pathogenesis of CLL, particular issues related to the study of clinical and morphological changes in individual organs and systems, in particular the skin, formed at various stages of the development of this disease should be studied in detail. This can not only expand and clarify our understanding of this pathology, but also can help to clarify the essence of the disease.

Current Antivirals and Novel Botanical Molecules Interfering With Herpes Simplex Virus Infection

Herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2) are highly prevalent within the human population and are characterized by lifelong infections and sporadic recurrences due to latent neuron infection. Upon reactivations, HSVs may manifest either, symptomatically or asymptomatically and be shed onto others through mucosae body fluids. Although, HSVs can produce severe disease in humans, such as life-threatening encephalitis and blindness, the most common symptoms are skin and mucosal lesions in the oro-facial and the genital areas. Nucleoside analogs with antiviral activity can prevent severe HSV infection, yet they are not very effective for treating skin manifestations produced by these viruses, as they only reduce in a few days at most the duration of lesions. Additionally, HSV variants that are resistant to these antivirals may arise, especially in immunosuppressed individuals. Thus, new antivirals that can reduce the severity and duration of these cutaneous manifestations would certainly be welcome. Here, we review currently available anti-herpetic therapies, novel molecules being assessed in clinical trials and new botanical compounds reported in the last 20 years with antiviral activities against HSVs that might represent future treatments against these viruses.

Prior inhibition of AKT phosphorylation by BX795 can define a safer strategy to prevent herpes simplex virus-1 infection of the eye

PURPOSE

To evaluate the prophylactic antiviral efficacy, corneal tolerance and toxicity of topically dosed BX795, a non-nucleoside small-molecule inhibitor of herpes simplex virus type-1 (HSV-1).

METHODS

Prophylactic treatment with BX795 was performed both in-vitro on human corneal epithelial cells and in-vivo on mice prior to HSV-1 challenge. Viral burden was evaluated using a standard plaque assay. In a separate experiment, mice were treated topically 3-times daily for 4-weeks with BX795 to evaluate corneal tolerance and toxicity. Phenol-red thread measurements, fluorescein staining and optical coherence tomography (OCT) were used to evaluate tear production, dryness and corneal structural changes. Corneal sensitivity and intraocular pressure were measured using esthesiometery and tonometery respectively.

RESULTS

Both in-vitro and in-vivo results showed a robust suppression of HSV-1 infection when treated prophylactically with BX795. The fluorescein stain and phenol-red results for the BX795-treated eyes did not show signs of corneal surface dryness when compared to trifluridine (TFT), an FDA-approved topical antiviral. The OCT measurements showed no signs of structural changes to the cornea suggesting that BX795 treatment was well tolerated without any apparent signs of toxicity or inflammation. The corneal sensitivity of BX795-treated eyes was not significantly different from TFT-treated eyes. No significant increase in the intraocular pressure of BX795-treated mice was observed.

CONCLUSIONS

Prophylactic treatment with BX795 protects corneal cells from HSV-1 infection. The antiviral is well-tolerated on murine corneas without any detectable toxicity.

An off-target effect of BX795 blocks herpes simplex virus type 1 infection of the eye

Herpes simplex virus type 1 (HSV-1) causes recurrent mucocutaneous lesions in the eye that may advance to corneal blindness. Nucleoside analogs exemplified by acyclovir (ACV) form the primary class of antiherpetic drugs, but this class suffers limitations due to the emergence of viral resistance and other side effects. While studying the molecular basis of ocular HSV-1 infection, we observed that BX795, a commonly used inhibitor of TANK-binding kinase 1 (TBK1), strongly suppressed infection by multiple strains of HSV-1 in transformed and primary human cells, cultured human and animal corneas, and a murine model of ocular infection. Our investigations revealed that the antiviral activity of BX795 relies on targeting Akt phosphorylation in infected cells, leading to the blockage of viral protein synthesis. This small-molecule inhibitor, which was also effective against an ACV-resistant HSV-1 strain, shows promise as an alternative to existing drugs and as an effective topical therapy for ocular herpes infection. Collectively, our results obtained using multiple infection models and virus strains establish BX795 as a promising lead compound for broad-spectrum antiviral applications in humans.

A Polyphenol Rich Extract from Solanum melongena L. DR2 Peel Exhibits Antioxidant Properties and Anti-Herpes Simplex Virus Type 1 Activity In Vitro

DR2B and DR2C extracts, obtained by ethanolic maceration of peel from commercially and physiologically ripe aubergine berries, were studied for the antioxidative cytoprotective properties and anti-HSV-1 activity, in line with the evidence that several antioxidants can impair viral replication by maintaining reducing conditions in host cells. The antioxidative cytoprotective effects against tBOOH-induced damage were assessed in Caco2 cells, while antiviral activity was studied in Vero cells; polyphenolic fingerprints were characterized by integrated phytochemical methods. Results highlighted different compositions of the extracts, with chlorogenic acid and delphinidin-3-rutinoside as the major constituents; other peculiar phytochemicals were also identified. Both samples reduced reactive oxygen species (ROS) production and exhibited scavenging and chelating properties. DR2C partly counteracted the tBOOH-induced cytotoxicity, with a remarkable lowering of lactate metabolism under both normoxia and hypoxia; interestingly, it increased intracellular GSH levels. Furthermore, DR2C inhibited the HSV-1 replication when added for 24 h after viral adsorption, as also confirmed by the reduction of many viral proteins' expression. Since DR2C was able to reduce NOX4 expression during HSV-1 infection, its antiviral activity may be correlated to its antioxidant properties. Although further studies are needed to better characterize DR2C activity, the results suggest this extract as a promising new anti-HSV-1 agent.

The Amphibian Antimicrobial Peptide Temporin B Inhibits In Vitro Herpes Simplex Virus 1 Infection

The herpes simplex virus 1 (HSV-1) is widespread in the population, and in most cases its infection is asymptomatic. The currently available anti-HSV-1 drugs are acyclovir and its derivatives, although long-term therapy with these agents can lead to drug resistance. Thus, the discovery of novel antiherpetic compounds deserves additional effort. Naturally occurring antimicrobial peptides (AMPs) represent an interesting class of molecules with potential antiviral properties. To the best of our knowledge, this study is the first demonstration of the in vitro anti-HSV-1 activity of temporin B (TB), a short membrane-active amphibian AMP. In particular, when HSV-1 was preincubated with 20 μg/ml TB, significant antiviral activity was observed (a 5-log reduction of the virus titer). Such an effect was due to the disruption of the viral envelope, as demonstrated by transmission electron microscopy. Moreover, TB partially affected different stages of the HSV-1 life cycle, including the attachment and the entry of the virus into the host cell, as well as the subsequent postinfection phase. Furthermore, its efficacy was confirmed on human epithelial cells, suggesting TB as a novel approach for the prevention and/or treatment of HSV-1 infections.

Delay of alternative antiviral therapy and poor outcomes of acyclovir-resistant herpes simplex virus infections in recipients of allogeneic stem cell transplant - a retrospective study

Acyclovir is commonly used to prevent and treat herpes simplex virus (HSV) reactivation after hematopoietic cell transplant (HCT), and only few reports have been published on acyclovir-resistant HSV in HCT recipients. We reviewed the medical records of patients with a microbiologic diagnosis of acyclovir-resistant HSV by plaque reduction test who received an HCT from 2002 through 2014. A total of 4 028 HCTs were performed during the study period, and 18 of the recipients met the diagnostic criteria for acyclovir-resistant HSV. All cases had undergone allogeneic HCTs. Most patients were in the pre-engraftment period or on systemic corticosteroid therapy for graft-versus-host disease (GVHD). The median time between diagnosis and susceptibility testing was 15 days, and antiviral therapy was changed at a median of 27 days. Patients required prolonged therapy (~80 days), and many had serious complications including renal failure and hospitalization. In conclusion, acyclovir-resistant HSV infection is more likely during the period of profound deficit in T-cell-mediated immunity and is associated with significant morbidities. Higher doses of acyclovir prophylaxis might be needed for patients with history of HSV during pre-engraftment or GVHD treatment. In patients who do not respond or progress after 1 week of acyclovir therapy, testing for drug-resistant HSV, and early switch to an alternative antiviral should be considered.

Antiviral resistance in herpes simplex virus and varicella-zoster virus infections: diagnosis and management

PURPOSE OF REVIEW

Aciclovir (ACV) is the first-line drug for the management of herpes simplex virus (HSV) and varicella-zoster virus (VZV) infections. Long-term administration of ACV for the treatment of severe infections in immunocompromised patients can lead to the development of drug resistance. Furthermore, the emergence of isolates resistant to ACV is increasingly recognized in immunocompetent individuals with herpetic keratitis. This review describes the mechanisms involved in drug resistance for HSV and VZV, the laboratory diagnosis and management of patients with infections refractory to ACV therapy.

RECENT FINDINGS

Genotypic testing is more frequently performed for the diagnosis of infections caused by drug-resistant HSV or VZV isolates. Molecular biology-based systems for the generation of recombinant viruses have been developed to link unknown mutations with their drug phenotypes. Fast and sensitive methods based on next-generation sequencing will improve the detection of heterogeneous viral populations of drug-resistant viruses and their temporal changes during antiviral therapy, which could allow better patient management. Novel promising compounds acting on targets that differ from the viral DNA polymerase are under clinical development.

SUMMARY

Antiviral drug resistance monitoring for HSV and VZV is required for a rational use of antiviral therapy in high-risk populations.

Cultured corneas show dendritic spread and restrict herpes simplex virus infection that is not observed with cultured corneal cells

Herpes simplex virus-1 (HSV-1) causes life-long morbidities in humans. While fever blisters are more common, occasionally the cornea is infected resulting in vision loss. A very intriguing aspect of HSV-1 corneal infection is that the virus spread is normally restricted to only a small fraction of cells on the corneal surface that connect with each other in a dendritic fashion. Here, to develop a comprehensive understanding of the susceptibility of human corneal epithelial (HCE) cells to HSV-1 infection, we infected HCE cells at three different dosages of HSV-1 and measured the outcomes in terms of viral entry, gene and protein expression, viral replication and cytokine induction. In cultured cells, infectivity and cytokine induction were observed even at the minimum viral dosage tested, while a more pronounced dose-restricted infectivity was seen in ex vivo cultures of porcine corneas. Use of fluorescent HSV-1 virions demonstrated a pattern of viral spread ex vivo that mimics clinical findings. We conclude that HCE cell cultures are highly susceptible to infection whereas the cultured corneas demonstrate a higher ability to restrict the infection even in the absence of systemic immune system. The restriction is helped in part by local interferon response and the unique cellular architecture of the cornea.

Extended Release of an Anti-Heparan Sulfate Peptide From a Contact Lens Suppresses Corneal Herpes Simplex Virus-1 Infection

PURPOSE

To prolong the release of a heparan sulfate binding peptide, G2-C, using a commercially available contact lens as a delivery vehicle and to demonstrate the ability of the released peptide to block herpes simplex virus-1 (HSV-1) infection using in vitro, ex vivo, and in vivo models of corneal HSV-1 infection.

METHODS

Commercially available contact lenses were immersed in peptide solution for 5 days prior to determining the release of the peptide at various time points. Cytotoxicity of the released samples was determined by MTT and cell cycle analysis, and the functional activity of the released samples were assessed by viral entry, and viral spread assay using human corneal epithelial cells (HCE). The ability to suppress infection in human and pig cornea ex vivo and mouse in vivo models were also assessed.

RESULTS

Peptide G2-C was released through the contact lens. Following release for 3 days, the peptide showed significant activity by inhibiting HSV-1 viral entry and spread in HCE cells. Significant suppression of infection was also observed in the ex vivo and in vivo experiments involving corneas.

CONCLUSIONS

Extended release of an anti-HS peptide through a commercially available contact lens can generate significant anti-HSV-1 activity and provides a new and effective way to control corneal herpes.

Synthetic α-Hydroxytropolones Inhibit Replication of Wild-Type and Acyclovir-Resistant Herpes Simplex Viruses

Herpes simplex virus 1 (HSV-1) and HSV-2 remain major human pathogens despite the development of anti-HSV therapeutics as some of the first antiviral drugs. Current therapies are incompletely effective and frequently drive the evolution of drug-resistant mutants. We recently determined that certain natural troponoid compounds such as β-thujaplicinol readily suppress HSV-1 and HSV-2 replication. Here, we screened 26 synthetic α-hydroxytropolones with the goals of determining a preliminary structure-activity relationship for the α-hydroxytropolone pharmacophore and providing a starting point for future optimization studies. Twenty-five compounds inhibited HSV-1 and HSV-2 replication at 50 μM, and 10 compounds inhibited HSV-1 and HSV-2 at 5 μM, with similar inhibition patterns and potencies against both viruses being observed. The two most powerful inhibitors shared a common biphenyl side chain, were capable of inhibiting HSV-1 and HSV-2 with a 50% effective concentration (EC50) of 81 to 210 nM, and also strongly inhibited acyclovir-resistant mutants. Moderate to low cytotoxicity was observed for all compounds (50% cytotoxic concentration [CC50] of 50 to >100 μM). Therapeutic indexes ranged from >170 to >1,200. These data indicate that troponoids and specifically α-hydroxytropolones are a promising lead scaffold for development as anti-HSV drugs provided that toxicity can be further minimized. Troponoid drugs are envisioned to be employed alone or in combination with existing nucleos(t)ide analogs to suppress HSV replication far enough to prevent viral shedding and to limit the development of or treat nucleos(t)ide analog-resistant mutants.

Safety, formulation, and in vitro antiviral activity of the antimicrobial peptide subtilosin against herpes simplex virus type 1

In the present study the antiviral properties of the bacteriocin subtilosin against Herpes simplex virus type 1 (HSV-1) and the safety and efficacy of a subtilosin-based nanofiber formulation were determined. High concentrations of subtilosin, the cyclical antimicrobial peptide produced by Bacillus amyloliquefaciens, were virucidal against HSV-1. Interestingly, at non-virucidal concentrations, subtilosin inhibited wild type HSV-1 and aciclovir-resistant mutants in a dose-dependent manner. Although the exact antiviral mechanism is not fully understood, time of addition experiments and western blot analysis suggest that subtilosin does not affect viral multiplication steps prior to protein synthesis. Poly(vinyl alcohol) (PVOH)-based subtilosin nanofibers with a width of 278 nm were produced by the electrospinning process. The retained antimicrobial activity of the subtilosin-based fibers was determined via an agar well diffusion assay. The loading capacity of the fibers was 2.4 mg subtilosin/g fiber, and loading efficiency was 31.6%. Furthermore, the nanofibers with and without incorporated subtilosin were shown to be nontoxic to human epidermal tissues using an in vitro human tissue model. Taking together these results subtilosin-based nanofibers should be further studied as a novel alternative method for treatment and/or control of HSV-1 infection.

Intravenous Foscarnet With Topical Cidofovir for Chronic Refractory Genital Herpes in a Patient With AIDS

Few case reports have documented the use of topical cidofovir for refractory genital herpes simplex virus (HSV) ulcers in human immunodeficiency virus (HIV) infected patients. This drug formulation lacks a standardized concentration or even a procedural outline as to how it should be compounded. We aim to discuss the utilization of topical cidofovir in addition to presenting a procedural means of compounding it for treatment of refractory genital HSV ulcers. Our patient completed 21 days of intravenous foscarnet and 13 days of topical cidofovir with clinical improvement in the penile and scrotal ulcers. Genital herpes is a concern in patients with HIV because it generally manifests as a persistent infection. Physicians should be aware that when patients fail to respond to the conventional treatment regimens for genital HSV in a timely manner, other options are available, such as topical cidofovir as an adjuvant to systemic antivirals.

Antiherpes simplex virus type 2 activity of the antimicrobial peptide subtilosin

AIMS

In this study, we evaluated the antiviral activity of subtilosin, a cyclical peptide isolated from Bacillus amyloliquefaciens, against herpes simplex virus type 2 (HSV-2) in cell cultures and we investigated subtilosin mode of action.

METHODS AND RESULTS

We determined, using a virus yield inhibition assay, that noncytotoxic concentrations of subtilosin inhibit HSV-2 replication in Vero cell cultures. Subtilosin strongly inhibited extracellular and total virus production even when it was added at 8 h postinfection indicating that not only virus release but also viral particle formation is impeded by the antiviral peptide. Although viral glycoprotein gD level of expression is not affected by the bacteriocin, an altered pattern of gD intracellular localization was detected by immunofluorescence assay in subtilosin-treated culture. On the other hand, at high concentrations, subtilosin displays virucidal action.

CONCLUSIONS

Subtilosin displays antiviral and virucidal actions against HSV-2. The target of subtilosin inhibitory effect would be late stages of the viral replicative cycle such as viral glycoprotein intracellular transport.

SIGNIFICANCE AND IMPACT OF THE STUDY

Given its antimicrobial activity and its safety for human tissues, subtilosin could represent a valuable alternative to be considered in the development of new microbicide formulations.

Single nucleotide polymorphisms of thymidine kinase and DNA polymerase genes in clinical herpes simplex virus type 1 isolates associated with different resistance phenotypes

The role of mutations in the thymidine kinase (TK, UL23) and DNA polymerase (pol, UL30) genes of herpes simplex virus (HSV) for development of different resistance phenotypes has to be exactly determined before genotypic resistance testing can be implemented in patient's care. Furthermore, the occurrence of cross-resistance is of utmost clinical importance. In this study, clinical HSV-1 isolates obtained between 2004 and 2011 from 26 patients after stem cell transplantation were examined in parallel by phenotypic and genotypic resistance testing. Thirteen isolates, which were phenotypically cross-resistant to acyclovir (ACV), penciclovir (PCV) and brivudin (BVDU), exhibited consistently frameshift or non-synonymous mutations in the TK gene known to confer resistance. One of these mutations (insertion of C at the nucleotide positions 1061-1065) has not been described before. Seven strains, phenotypically resistant to ACV and PCV and, except one each, sensitive to BVDU and resistant to foscarnet (FOS), carried uniformly resistance-related substitutions in the DNA pol gene. Finally, 3 isolates, resistant to ACV, PCV and 2 out of these also resistant to BVDU, had known but also unclear substitutions in the TK and DNA pol genes, and 3 isolates were completely sensitive. In conclusion, clinical ACV-resistant HSV-1 isolates, carrying resistance-associated mutations in the TK gene, can be regarded as cross-resistant to other nucleoside analogs such as BVDU. In contrast, clinical FOS-resistant HSV-1 strains which are cross-resistant to ACV may be sensitive to BVDU. This has to be considered for drug changes in antiviral treatment in case of ACV resistance.

Oral complications and management strategies for patients undergoing cancer therapy

With cancer survival rate climbing up over the past three decades, quality of life for cancer patients has become an issue of major concern. Oral health plays an important part in one's overall quality of life. However, oral health status can be severely hampered by side effects of cancer therapies including surgery, chemotherapy, radiotherapy, and hematopoietic stem cell transplantation. Moreover, prevention and treatment of these complications are often overlooked in clinical practice. The present paper aims at drawing health care professionals' attention to oral complications associated with cancer therapy by giving a comprehensive review. Brief comments on contemporary cancer therapies will be given first, followed by detailed description of oral complications associated with cancer therapy. Finally, a summary of preventive strategies and treatment options for common oral complications including oral mucositis, oral infections, xerostomia, and dysgeusia will be given.

Eczema herpeticum with herpetic folliculitis after bone marrow transplant under prophylactic acyclovir: are patients with underlying dermatologic disorders at higher risk?

We present an unreported coexistence: eczema herpeticum (EH) with histopathological findings of herpetic folliculitis (HF) after allogeneic bone marrow transplantation (BMT). A patient with atopic dermatitis (AD) underwent allogeneic BMT for idiopathic acquired aplastic anemia. She had been receiving cyclosporine (150 mg/12 h) and acyclovir (400 mg/12 h) for 6 months. A facial rash was observed, composed of monotonous erythematous, umbilicated papulo-vesicles and papulo-crusts <4 mm in size. The histopathological study showed herpetic cytopathic changes within the epidermis that extended into the hair follicle epithelium. Interestingly, microscopic HF has not previously been associated with post-transplant patients or EH. However, it is reasonable to hypothesize that the coexistence of these herpes simplex virus-related events may be underreported in the literature. Although further studies are necessary, we suggest that the prophylactic antiviral dose after BMT be enhanced in patients with underlying dermatologic diseases, especially in those with AD.

In vitro antiviral activity of dehydroepiandrosterone, 17 synthetic analogs and ERK modulators against herpes simplex virus type 1

In the present study the in vitro antiviral activity of dehydroepiandrosterone (DHEA) and 17 synthetic derivatives against herpes simplex type 1 (HSV-1) was determined. DHEA, epiandrosterone (EA), two synthetic DHEA analogs and three synthetic EA analogs showed a selective inhibitory effect on HSV in vitro multiplication. DHEA and E2, a synthetic derivative of EA, were not found to be virucidal to cell-free HSV-1 and did not impair virus adsorption or penetration. We determined that treatment with both compounds decreased viral protein synthesis. Moreover, inhibitory effect of DHEA and E2 on extracellular viral titer was stronger than the inhibition found on total viral infectivity, suggesting that the antiherpetic activity of these compounds may also be in part due to an inhibition in virus formation and release. Since DHEA is a known Raf/MEK/ERK signaling pathway activator, we studied the role of this pathway on HSV-1 infection. ERK1/2 phosphorylation was stimulated in HSV-1 infected cultures. UO126, a Raf/MEK/ERK signaling pathway inhibitor, impaired viral multiplication, while anisomycin, an activator of this pathway, enhanced it. Treatment with DHEA 6 h before infection enhanced HSV-1 multiplication. On the contrary, pre-treatment with E2, which does not modulate Raf/MEK/ERK signaling pathway, did not produce an increase of viral replication. Taking together these results, the antiviral activity of DHEA seems to occur via a mechanism independent of its ability to modulate ERK phosphorylation.

Novel resistance-associated mutations of thymidine kinase and DNA polymerase genes of herpes simplex virus type 1 and type 2

BACKGROUND

Studies to verify correlations between phenotypes and genotypes of herpes simplex virus (HSV) are an important tool to establish a database of resistance-associated mutations.

METHODS

In this study, 32 acyclovir (ACV)-resistant clinical HSV-1 and 4 ACV-resistant clinical HSV-2 isolates were examined in parallel by both phenotypic and genotypic resistance testing. Additionally, five non-viable HSV-1 strains and two non-viable HSV-2 strains with clinical resistance were included in genotypic resistance analysis.

RESULTS

All ACV-resistant HSV isolates showed cross-resistance to brivudin and penciclovir, and were sensitive to foscarnet and cidofovir. Acyclovir resistance was assigned to frameshift and single non-synonymous mutations of the thymidine kinase (TK) gene in 32 out of 37 HSV-1 strains and in 4 out of 6 HSV-2 strains. In three HSV-1 isolates, there were resistance-associated amino acid substitutions of the DNA polymerase (pol). Six substitutions in the TK and two in the DNA pol gene could not be attributed without doubt to either ACV resistance or natural gene polymorphism. Altogether, 10 resistance-related mutations in the TK and 1 in the DNA pol gene have not been reported previously.

CONCLUSIONS

The novel non-synonymous mutations found in this study enrich the knowledge about the genetic alterations of TK and DNA pol genes in ACV-resistant clinical HSV strains. Together with data from the literature, the findings justify the generation of a HSV database that contains resistance mutations associated with ACV resistance phenotype.

Chronic mucocutaneous herpes simplex virus and varicella zoster virus infections

Chronic herpes simplex virus (CHSV) and chronic varicella zoster virus (CVZV) are defined as atypical mucocutaneous wart-like and/or ulcerative HSV or VZV infections, persisting for at least 1 month. Both are commonly associated with HIV infection and may occasionally present with other types of immunosuppression. CHSV and CVZV occur despite the immune restoration effect of highly active antiretroviral therapy for HIV. The clinical polymorphism of CHSV and CVZV makes recognition difficult. Histology, immunohistology, PCR and viral culture all help to confirm the diagnosis. Treatment is frequently complicated by resistance to thymidine kinase (TK)-dependent antivirals, including acyclovir, valacyclovir and famciclovir. Viral culture remains an essential tool for antiviral drug susceptibility testing. Therapeutic alternatives include non-TK-dependent antivirals, such as foscarnet or cidofovir, which directly target viral DNA polymerase. With few exceptions, CHSV and CVZV infections do not constitute significant risk factors for disseminated cutaneous or systemic infection. This review compares the similarities of and differences between CHSV and CVZV infections.

High-intensity laser and photodynamic therapy as a treatment for recurrent herpes labialis

OBJECTIVE

The aim of this study was to report the treatment of recurrent herpes labialis (RHL) using a high-intensity laser or methylene blue (MB)-mediated photodynamic therapy (PDT) in combination with low-level laser therapy (LLLT).

MATERIALS AND METHODS

Four clinical cases of patients diagnosed with RHL are described in this report. Two patients were subjected to high-intensity laser therapy (HILT) followed by LLLT, and two patients received MB-mediated PDT, again followed by LLLT. LLLT was conducted at 24, 48, 72 h, and 7 d after HILT or PDT. Patients were followed up after 6 mo.

RESULTS

Throughout the follow-up period, all patients reported pain relief and did not show any signs or symptoms of RHL. A favorable healing process was observed in all cases. None of the patients reported pain as a consequence of the treatment.

CONCLUSION

These results suggest that HILT and MB-mediated PDT, in combination with LLLT, may constitute a benefit when treating vesicles in RHL.

Herpes Simplex Virus (HSV) Immediate-Early (IE) Promoter-Directed Reporter System for the Screening of Antiherpetics Targeting the Early Stage of HSV Infection

Most of the current antiherpetics target viral DNA polymerase, but with the emergence of drug-resistant viruses, antiherpetics with different targets have become necessary. Inhibition of herpes simplex virus (HSV) replication at the early stages of infection minimizes cytotoxicity and immune suppression induced by HSV infection. In this report, quantitative reporter systems that use recombinant HSV and a stably transfected cell line were developed for the screening of agents targeting the early stages of HSV infection. The reporter genes in both systems were directed by HSV immediate-early (IE) promoters, so considerably less time was required for the quantification of HSV infection than the traditional plaque reduction assay. The results show that both reporter assays were sensitive to antiherpetic screening. Both assays were quantitative, rapid, easy to perform, and highly adaptable for automatic high-throughput screening. Exploiting the flexibility of these 2 assays, modified assays were also proposed for the detailed analysis of antiherpetic mechanisms.

The diagnosis and management of oral herpes simplex infection

Acute herpetic gingivostomatitis and recurrent herpes labialis are the most common manifestations of infection with herpes simplex virus type 1 (HSV-1). In primary and recrudescent HSV-associated disease, the symptoms may range from subclinical to debilitating and life-threatening, depending on the host's immune responses or competence level. In this paper, the typical and atypical manifestations, and the current diagnostic and treatment options for localized, non-complicated oro-labial HSV infection are reviewed, with attention to cumulative evidence for the efficacy and safety of systemic antiviral agents. Some recent data on HSV-1 seroprevalence, viremia, and viral shedding are discussed in relation to disease transmission and global importance of herpesvirus disease.

Therapeutic approaches using host defence peptides to tackle herpes virus infections

One of the most common viral infections in humans is caused by herpes simplex virus (HSV). It can easily be treated with nucleoside analogues (e.g., acyclovir), but resistant strains are on the rise. Naturally occurring antimicrobial peptides have been demonstrated to possess antiviral activity against HSV. New evidence has also indicated that these host defence peptides are able to selectively stimulate the innate immune system to fight of infections. This review will focus on the anti-HSV activity of such peptides (both natural and synthetic), describe their mode of action and their clinical potential.

Interventions for the prevention and treatment of herpes simplex virus in patients being treated for cancer

BACKGROUND

Treatment of cancer is increasingly effective, but associated with oral complications such as mucositis, fungal infections, bacterial infections and viral infections such as the herpes simplex virus (HSV).

OBJECTIVES

To examine the effects of interventions for the prevention or treatment or both, of herpes simplex virus in patients receiving treatment for cancer.

SEARCH STRATEGY

We searched the following databases: Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE, EMBASE, CINAHL, CANCERLIT, SIGLE and LILACS. The reference list of all related review articles and articles considered to be potentially relevant were checked for further trials. Authors of identified trials and known specialists in the field were also contacted in an attempt to identify any additional published or unpublished trials. Date of most recent search: November 2008.

SELECTION CRITERIA

All randomised controlled trials comparing interventions for the prevention or treatment or both of HSV infection in people being treated for cancer. Outcomes were presence/absence of clinical/culture positive HSV infections (prevention), time to complete healing of lesions (treatment), duration of viral shedding, recurrence of lesions, relief of pain, amount of analgesia, duration of hospital stay, cost of oral care, patient quality of life and adverse effects.

DATA COLLECTION AND ANALYSIS

Data were independently extracted, in duplicate, by two review authors. Authors were contacted for details of randomisation, blindness and sample demographics where necessary. Quality assessment was carried out on randomisation, blindness, withdrawals and selective reporting. The Cochrane Collaboration's statistical guidelines were followed and risk ratio (RR) values were calculated using random-effects models.

MAIN RESULTS

Seventeen trials satisfied the inclusion criteria. Four trials evaluated preventative interventions for HSV lesions, three trials for viral isolates, and eight trials evaluated both outcome measures. A single trial reported on the cost of prophylaxis for HSV. Two trials evaluating treatment reported on time to healing, duration of viral shedding and relief of pain. No trials reported on duration of hospital stay, amount of analgesia or patient quality of life.In placebo controlled trials, aciclovir was found to be effective for the prevention of HSV infections as measured by oral lesions or viral isolates (RR = 0.16, 95% confidence interval (CI) 0.08 to 0.31 nine trials; RR = 0.17, 95% CI 0.07 to 0.37 nine trials). There is no evidence that valaciclovir is more efficacious than aciclovir, or that higher doses of valaciclovir are more effective than lower doses. Placebo was found to be more effective than prostaglandin E for prevention of viral isolates (RR = 1.87, 95% CI 1.12 to 3.14 one trial).Aciclovir was also found to be effective for the treatment of HSV in terms of duration of viral shedding (median of 2.5 days versus 17.0 days, P = 0.0002; 2 days compared to more than 9, P = 0.0008), time to first decrease in pain (median 3 days compared to 16, P = 0.04), complete resolution of pain (9.9 days compared to 13.6 days, P = 0.01; median of 6 days compared to 16, P = 0.05), 50% healing (median of 6 days compared to 11, P = 0.01) and total healing (median 13.9 days compared to 20.7 days, P = 0.08; median of 8 days compared to 21, P = 0.0).

AUTHORS' CONCLUSIONS

There is evidence that aciclovir is efficacious in the prevention and treatment of herpes simplex virus infections. There is no evidence that valaciclovir is more efficacious than aciclovir, or that a high dose of valaciclovir is better than a low dose of valaciclovir. There is evidence that as a prophylaxis, placebo is more efficacious than prostaglandin E. However, in all included trials, risk of bias is unclear.

Human herpes simplex labialis

Humans are the natural host for eight of more than 80 known herpes viruses. Infections with herpes simplex virus type 1 (HSV-1) are ubiquitous worldwide and highly transmissible. Herpes simplex labialis (HSL) is the best-recognized recrudescent infection of the lips and perioral tissues caused by HSV-1. Facial lesions of HSL may be unsightly, frequent outbreaks unpleasant, and the infection itself more severe locally and systemically in immunocompromised people. This article highlights the pathogenesis, clinical presentation, diagnostic features and management issues for HSL.

A-5021: a new acyclovir analogue inhibits murine herpetic keratitis

PURPOSE

To determine the efficacy of A-5021, a new analogue of acyclovir, on murine herpetic keratitis.

METHODS

Herpes simplex virus type 1 (strain CHR3) was inoculated onto bilateral scarified BALB/c corneas. Clinical scores on the corneas treated with A-5021 eyedrops were compared with those obtained from the treatment with 3% acyclovir eye ointment by slit lamp microscopy. Virus titers of the trigeminal ganglia and eyeballs were quantitated on Vero cell monolayers. Mice treated with saline or a white petroleum jelly were used as controls.

RESULTS

A-5021 eyedrops significantly suppressed both corneal epithelial and stromal lesions at all concentrations used. Clinical scores on the epithelium and stroma treated with 0.1% A-5021 were equivalent to those with 3% acyclovir treatment. When compared with the non-drug-treated control mice, virus titers in the eyeballs and trigeminal ganglia in A-5021- and acyclovir-treated mice were significantly less than those in controls.

CONCLUSIONS

A-5021 eyedrops, which are easily applied onto the affected cornea, ameliorated clinical scores and suppressed virus growth. It is a promising alternative treatment of herpetic keratitis.

Foscarnet salvage therapy for acyclovir-resistant varicella zoster: report of a novel thymidine kinase mutation and review of the literature

The authors describe an acyclovir-resistant varicella zoster virus infection in a pediatric patient after hematopoietic stem cell transplant, the use of foscarnet as salvage therapy, and review the literature to clarify the pediatric experience with foscarnet in this setting. A novel thymidine kinase mutation is described, along with a new phenotypic assay for characterizing acyclovir resistance in varicella zoster virus.

Human herpes simplex virus infections: epidemiology, pathogenesis, symptomatology, diagnosis, and management

Eight of the more than 80 known herpesviruses are human pathogens. Human herpes simplex virus (HSV) is a contagious infection with a large reservoir in the general population. It has a potential for significant complications in the immunocompromised host. In addition, psychological distress caused by the negative stigma associated with genital herpes and visible facial lesions in those experiencing frequent outbreaks renders it a challenging clinical dilemma. This article reviews the epidemiology, pathogenesis, and diagnostic features of HSV infections, providing the clinician with an up-to-date understanding of the available management strategies for mucocutaneous HSV-induced disease.

Antimicrobial resistance prevention initiative--an update: proceedings of an expert panel on resistance

Antimicrobial resistance is a growing problem that complicates the treatment of important nosocomial and community-acquired infections. It is a worldwide problem that spans the range of human pathogens, including bacteria, fungi, and viruses. This update from the Antimicrobial Resistance Prevention Initiative (ARPI) provides a review of some important trends in antibiotic, antifungal, and antiviral resistance. Areas of focus include multidrug-resistant bacteria in the hospital setting; the growing problem of community-acquired methicillin-resistant Staphylococcus aureus; triazole and polyene resistance in nosocomial infections caused by non-Candida albicans or Aspergillus species, and the utility of in vitro susceptibility testing for these fungal infections; antiviral resistance in alpha- or beta-herpesviruses causing genital herpes or cytomegalovirus infection in immunocompromised hosts; and concerns about a possible pandemic involving avian influenza A and the importance of minimizing emergence of resistant strains of this highly pathogenic virus. The challenges in each area are different, but the general keys to addressing the growing problem of antimicrobial resistance continue to be responsible antimicrobial stewardship and the development of newer antimicrobial agents.