Comparison of the antiviral action of different human interferons against DNA and RNA viruses

Abstract Five different interferon preparations were compared for their antiviral activity against Herpes simplex virus type 1 (HSV-1) and several RNA viruses. The interferons used were: interferon α from human buffy coats, interferon β from human fibroblasts, interferon γ from human lymphocytes after stimulation with phytohemagglutinin (PHA), lymphoblastoid interferon from Namalva cells IFN-α (Ly) and cloned α ₂ interferon produced by Escherichia coli containing the human gene for interferon α ₂. All preparations were able to protect monolayers of HeLa cells against HSV-1 infection when low multiplicities were used. The five IFN preparations were also tested against encephalomyocarditis (EMC) virus, poliovirus and vesicular stomatitis virus (VSV).     

Encapsulation of Lactobacillus plantarum 423 and its Bacteriocin in Nanofibers

Plantaricin 423, produced by Lactobacillus plantarum 423, was encapsulated in nanofibers that were produced by the electrospinning of 18% (w/v) polyethylene oxide (200 000 Da). The average diameter of the nanofibers was 288 nm. Plantaricin 423 activity decreased from 51 200 AU/ml to 25 600 AU/ml and from 204 800 AU/ml to 51 200 AU/ml after electrospinning, as determined against Lactobacillus sakei DSM 20017 and Enterococcus faecium HKLHS, respectively. Cells of L. plantarum 423 encapsulated in nanofibers decreased from 2.3 × 10¹⁰ cfu/ml before electrospinning to 4.7 × 10⁸ cfu/ml thereafter. Cells entrapped in the nanofibers continued to produce plantaricin 423. This is the first report on the encapsulation of a bacteriocin and cells of L. plantarum in nanofibers. The method may be used to design a drug delivery system for bacteriocins and the encapsulation of probiotic lactic acid bacteria. The technology is currently being optimized.     

Influence of pH and temperature on the expression of sboA and ituD genes in Bacillus sp. P11

Temperature and pH are key factors influencing the production of antimicrobial peptides. In this work, qRT-PCR methodology was used to demonstrate the effect of these two variables on sboA (subtilosin A) and ituD (iturin A) expression in Bacillus sp. P11, an isolate from aquatic environment of the Amazon. Bacillus sp. P11 was incubated in BHI broth for 36 h at 30, 37 and 42 °C, and the pH values were 6.0, 7.4 and 8.0. The production of subtilosin A and iturin A was confirmed by mass spectrometry. The sboA expression increased 200-fold when the initial pH was 8.0. In contrast, ituD expression was maximum at pH 6.0. Increased temperature (42 °C) was adverse for both genes, but ituD expression increased at 37 °C. Expression of sboA and ituD was strongly affected by pH and temperature and qRT-PCR proved to be a powerful tool to investigate the potential of Bacillus strains to produce subtilosin A and iturin A.     

Antiherpetic (HSV-1) activity of carrageenans from the red seaweed <Emphasis Type="Italic">Solieria chordalis</Emphasis> (Rhodophyta,Gigartinales) extracted by microwave-assisted extraction (MAE)

Carrageenan yield, physicochemical properties, and antiviral activity of the carrageenan from Solieria chordalis (Rhodophyceae, Solieriaceae) harvested at the Brittany coast (France) were investigated. S. chordalis carrageenan was extracted by conventional and the microwave-assisted extraction (MAE) methods. The effect of different parameters during MAE extraction such as alkali concentration (0, 0.5 and 1% KOH), extraction time (10, 20, and 25 min) and temperature (90 and 105 °C) were evaluated. Native carrageenan extracted by MAE had the highest yield (29.3%) after 10 min at 90 °C. After alkali treatment, carrageenan yield ranged from 10.7 to 18.4%. No significant differences in the carrageenan yield were observed between MAE and conventional method under alkaline conditions. Chemical analysis and FTIR spectra revealed the presence of a predominant iota-carrageenan. Evaluation of the antiviral activity of S. chordalis carrageenan against HSV-1 (Herpes simplex virus type 1) showed a EC₅₀ of the iota-carrageenans fractions in the range of 3.2 to 54.4 μg mL^?1 (MOI 0.01 ID₅₀ mL^?1) without cytotoxicity in that range of concentrations.     

Chromium(III) and iron(III) inhibits replication of DNA and RNA viruses

The aim of this study was to examine the effect of treating of chromium(III) and iron(III) and their combinations on Herpes Simplex Virus type 1 (HSV-1) and Bovine Viral Diarrhoea virus (BVDV) replication. The antiviral efficacies of chromium(III) and iron(III) on HSV-1 and BVDV were evaluated using Real Time PCR method. Moreover, the cytotoxicity of these microelements was examined using the MTT reduction assay. The IC₅₀ (50% inhibiotory concentration) for the chromium chloride was 1100 μM for Hep-2 cells and 1400 μM for BT cells. The IC₅₀ for the iron chloride was 1200 μM for Hep-2 cells and more than1400 μM for BT cells. The concentration-dependent antiviral activity of chromium chloride and iron chloride against HSV-1 and BVDV viruses was observed. In cultures simultaneously treated with (1) 200 μM of CrCl₃ and 1000 μM of FeCl₃, (2) 1000 μM of CrCl₃ and 200 μM of FeCl₃, (3) 400 μM of CrCl₃ and 800 μM of FeCl₃, (4) 800 μM of CrCl₃ and 400 μM of FeCl₃ a decrease in number of DNA or RNA copies was observed compared with control cells and cells incubated with chromium(III) and iron(III) used separately. The synergistic antiviral effects were observed for chromium(III) and iron(III) against HSV-1 and BVDV.     

Comparison of disc diffusion, Etest and broth microdilution for testing susceptibility of carbapenem-resistant P. aeruginosa to polymyxins

Background

New prophylactic and therapeutic tools are needed for the treatment of herpes simplex virus infections. Several essential oils have shown to possess antiviral activity in vitro against a wide spectrum of viruses.

Aim

The present study was assess to investigate the activities of the essential oil obtained from leaves of Artemisia arborescens against HSV-1 and HSV-2

Methods

The cytotoxicity in Vero cells was evaluated by the MTT reduction method. The IC₅₀ values were determined by plaque reduction assay. In order to characterize the mechanism of action, yield reduction assay, inhibition of plaque development assay, attachment assay, penetration assay and post-attachment virus neutralization assay were also performed.

Results

The IC₅₀ values, determined by plaque reduction assay, were 2.4 and 4.1 μg/ml for HSV-1 and HSV-2, respectively, while the cytotoxicity assay against Vero cells, as determined by the MTT reduction method, showed a CC₅₀ value of 132 μg/ml, indicating a CC₅₀/IC₅₀ ratio of 55 for HSV-1 and 32.2 for HSV-2. The antiviral activity of A. arborescens essential oil is principally due to direct virucidal effects. A poor activity determined by yield reduction assay was observed against HSV-1 at higher concentrations when added to cultures of infected cells. No inhibition was observed by attachment assay, penetration assay and post-attachment virus neutralization assay. Furthermore, inhibition of plaque development assay showed that A. arborescens essential oil inhibits the lateral diffusion of both HSV-1 and HSV-2.

Conclusion

This study demonstrates the antiviral activity of the essential oil in toto obtained from A. arborescens against HSV-1 and HSV-2. The mode of action of the essential oil as antiherpesvirus agent seems to be particularly interesting in consideration of its ability to inactivate the virus and to inhibit the cell-to-cell virus diffusion.     

Antimicrobial and antiviral activity-guided fractionation from Scutia buxifolia Reissek extracts

Antimicrobial and antiviral activities of the fractions from Scutia buxifolia stem bark and leaves were evaluated. Best antimicrobial results occurred with the ethyl acetate (EA) and n-butanolic (NB) fractions from the leaves against Micrococcus sp. (minimal inhibitory concentration—MIC = 62.5 μg/ml), and NB fraction from stem bark and leaves against Klebsiella pneumoniae and Enterococcus faecalis (MIC = 62.5 μg/ml). The most active fractions were selected and fractioned into silica column to perform an in vitro antibiofilm assay, which evidenced subfractions EA2 and EA3 as the more active against Candida albicans (biofilm inhibitory concentration—BIC = 582 ± 0.01 μg/ml) and Staphylococcus aureus (BIC = 360 ± 0.007 μg/ml), respectively. The NB (selectivity index—SI = 25.78) and the EA (SI = 15.97) fractions from the stem bark, and the EA (SI = 14.13) fraction from the leaves exhibited a potential antiviral activity towards Herpes Simplex Virus type 1 whereas EA2 and EA3 subfractions from leaves (SI = 12.59 and 10.06, respectively), and NB2 subfraction from stem bark (SI = 12.34) maintained this good activity. Phenolic acids and flavonoids (gallic acid, chlorogenic acid, caffeic acid, rutin, isoquercitrin, quercitrin and quercetin) were identified by HPLC and may be partially responsible for the antimicrobial and antiherpes activities observed. The results obtained in this study showed that Scutia buxifolia has antibiofilm and anti-herpetic activities and that these properties are reported for the first time for this species.     

Modifications on the heterocyclic base of ganciclovir,penciclovir, acyclovir - syntheses and antiviral properties

АBSTRACT

Esters of the antiherpetic drugs ganciclovir, penciclovir with the bile acids (cholic, chenodeoxycholic and deoxycholic) and amino acid esters of acyclovir were generated and evaluated for their in vitro antiviral activity against herpes simplex viruses type 1 and type 2 (HSV-1, HSV-2). The antiviral assays demonstrated that modified analogs of ACV and PCV are less active compared to the initial substances against HSV-1and HSV-2. CC50 for ganciclovir-deoxycholate corresponded to the CC50 of the other analogs and its activity is lower than ganciclovir. Obtained results show that tested modification do not improve bioavailability of nucleoside analogs in cells.     

Subtilosin Prevents Biofilm Formation by Inhibiting Bacterial Quorum Sensing

Subtilosin, the cyclic lantibiotic protein produced by Bacillus subtilis KATMIRA1933, targets the surface receptor and electrostatically binds to the bacterial cell membrane. In this study, subtilosin was purified using ammonium sulfate ((NH₄)₂SO₄) precipitation and purified via column chromatography. Subtilosin’s antibacterial minimum and sub-minimum inhibitory concentrations (MIC and sub-MIC) and anti-biofilm activity (biofilm prevention) were established. Subtilosin was evaluated as a quorum sensing (QS) inhibitor in Gram-positive bacteria using Fe(III) reduction assay. In Gram-negative bacteria, subtilosin was evaluated as a QS inhibitor utilizing Chromobacterium voilaceum as a microbial reporter. The results showed that Gardnerella vaginalis was more sensitive to subtilosin with MIC of 6.25 μg/mL when compared to Listeria monocytogenes (125 μg/mL). The lowest concentration of subtilosin, at which more than 90% of G. vaginalis biofilm was inhibited without effecting the growth of planktonic cells, was 0.78 μg/mL. About 80% of L. monocytogenes and more than 60% of Escherichia coli biofilm was inhibited when 15.1 μg/mL of subtilosin was applied. Subtilosin with 7.8–125 μg/mL showed a significant reduction in violacein production without any inhibitory effect on the growth of C. violaceum. Subtilosin at 3 and 4 μg/mL reduced the level of Autoinducer-2 (AI-2) production in G. vaginalis. However, subtilosin did not influence AI-2 production by L. monocytogenes at sub-MICs of 0.95–15.1 μg/mL. To our knowledge, this is the first report exploring the relationship between biofilm prevention and quorum sensing inhibition in G. vaginalis using subtilosin as a quorum sensing inhibitor.     

Design and Synthesis of Novel 1′,3′-Dioxolane 5′-Deoxyphosphonic Acid Purine Analogues as Potent Antiviral Agents

Electronic parameters of 1′,3 ′-oxygen play significant roles in steering the conformation of nucleoside phosphonic acid analogues. To investigate the relationship of two oxygen atoms with antiviral enhancement, novel 1′,3 ′-dioxolane 5 ′-deoxyphosphonic acid purine analogues were synthesized via de novo acyclic stereoselective route from acrolein and glycolic acid. The synthesized nucleoside phosphonic acid analogues 14 and 19 were subjected to antiviral screening against several viruses, such as HIV-1, HSV-1, HSV-2, and HCMV. The guanine analogue 19 exhibits in vitro anti-HIV-1 activity similar to that of 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA) in MT-4 cells.     

ACYCLIC/CARBOCYCLIC GUANOSINE ANALOGUES AS ANTI-HERPESVIRUS AGENTS

Several guanosine analogues, i.e. acyclovir (and its oral prodrug valaciclovir), penciclovir (in its oral prodrug form, famciclovir) and ganciclovir, are widely used for the treatment of herpesvirus [i.e. herpes simplex virus type 1 (HSV-1), and type 2 (HSV-2),varicella-zoster virus (VZV) and/or human cytomegalovirus (HCMV)] infections. In recent years, several new guanosine analogues have been developed, including the 3-membered cyclopropylmethyl and-methenyl derivatives (A-5021 and synguanol) and the 6-membered D-and L-cyclohexenyl derivatives. The activity of the acyclic/carbocyclic guanosine analogues has been determined against a wide spectrum of viruses, including the HSV-1, HSV-2, VZV, HCMV, and also human herpesviruses type 6 (HHV-6), type 7 (HHV-7) and type 8 (HHV-8), and hepatitis B virus (HBV). The new guanosine analogues (i.e. A-5021 and D- and L-cyclohexenyl G) were found to be particularly active against those viruses (HSV-1, HSV-2, VZV) that encode for a specific thymidine kinase (TK), suggesting that their antiviral activity (at least partially) depends on phosphorylation by the virus-induced TK. Marked antiviral activity was also noted with A-5021 against HHV-6 and with D- and L-cyclohexenyl G against HCMV and HBV. The antiviral activity of the acyclic/carbocyclic nucleoside analogues could be markedly potentiated by mycophenolic acid, a potent inhibitor of inosine 5′-monophosphate (IMP) dehydrogenase. The new carbocyclic guanosine analogues (i.e. A-5021 and D- andL-cyclohexenyl G) hold great promise, not only as antiviral agents for the treatment of herpesvirus infections, but also an antitumor agents for the combined gene therapy/chemotherapy of cancer, provided that (part of) the tumor cells have been transduced by the viral (HSV-1, VZV) TK gene.     

Acyclic/carbocyclic guanosine analogues as anti-herpesvirus agents

Several guanosine analogues, i.e. acyclovir (and its oral prodrug valaciclovir), penciclovir (in its oral prodrug form, famciclovir) and ganciclovir, are widely used for the treatment of herpesvirus [i.e. herpes simplex virus type 1 (HSV-1), and type 2 (HSV-2), varicella-zoster virus (VZV) and/or human cytomegalovirus (HCMV)] infections. In recent years, several new guanosine analogues have been developed, including the 3-membered cyclopropylmethyl and -methenyl derivatives (A-5021 and synguanol) and the 6-membered D- and L-cyclohexenyl derivatives. The activity of the acyclic/carbocyclic guanosine analogues has been determined against a wide spectrum of viruses, including the HSV-1, HSV-2, VZV, HCMV, and also human herpesviruses type 6 (HHV-6), type 7 (HHV-7) and type 8 (HHV-8), and hepatitis B virus (HBV). The new guanosine analogues (i.e. A-5021 and D- and L-cyclohexenyl G) were found to be particularly active against those viruses (HSV-1, HSV-2, VZV) that encode for a specific thymidine kinase (TK), suggesting that their antiviral activity (at least partially) depends on phosphorylation by the virus-induced TK. Marked antiviral activity was also noted with A-5021 against HHV-6 and with D- and L-cyclohexenyl G against HCMV and HBV. The antiviral activity of the acyclic/carbocyclic nucleoside analogues could be markedly potentiated by mycophenolic acid, a potent inhibitor of inosine 5'-monophosphate (IMP) dehydrogenase. The new carbocyclic guanosine analogues (i.e. A-5021 and D- and L-cyclohexenyl G) hold great promise, not only as antiviral agents for the treatment of herpesvirus infections, but also an antitumor agents for the combined gene therapy/chemotherapy of cancer, provided that (part of) the tumor cells have been transduced by the viral (HSV-1, VZV) TK gene.     

The antiviral activity of 9-beta-D-arabinofuranosyladenine is enhanced by the 2',3'-dideoxyriboside, the 2',3'-didehydro-2',3'-dideoxyriboside and the 3'-azido-2',3'-dideoxyriboside of 2,6-diaminopurine

The 2',3'-dideoxyriboside (ddDAPR), 2',3'-didehydro-2',3'-dideoxyriboside (ddeDAPR) and 3'-azido-2',3'-dideoxyriboside (AzddDAPR) of 2,6-diaminopurine have been previously recognized as potent inhibitors of human immunodeficiency virus replication. These compounds are also potent inhibitors of adenosine deaminase and inhibit the deamination of 9-beta-D-arabinofuranosyladenine (araA). ddDAPR, ddeDAPR and AzddDAPR markedly potentiate the antiviral activity of araA against herpes simplex virus type 1 (HSV-1), type 2 (HSV-2) and vaccinia virus (VV). When used at a concentration of 20 micrograms/ml, which had by itself no antiviral effect, ddDAPR, ddeDAPR and AzddDAPR increased the ability of araA to suppress HSV-1, HSV-2 and VV yield by several orders of magnitude. The maximum antiviral effect was obtained with the combinations of ddDAPR or ddeDAPR with araA concentrations of 1 and 10 micrograms/ml.     

In vitro antiviral activity of Melaleuca alternifolia essential oil

Aims:  To investigate the in vitro antiviral activity of Melaleuca alternifolia essential oil (TTO) and its main components, terpinen-4-ol, α-terpinene, γ-terpinene, p -cymene, terpinolene and α-terpineol.
Methods and Results:  The antiviral activity of tested compounds was evaluated against polio type 1, ECHO 9, Coxsackie B1, adeno type 2, herpes simplex (HSV) type 1 and 2 viruses by 50% plaque reduction assay. The anti-influenza virus assay was based on the inhibition of the virus-induced cytopathogenicity. Results obtained from our screening demonstrated that the TTO and some of its components (the terpinen-4-ol, the terpinolene, the α-terpineol) have an inhibitory effect on influenza A/PR/8 virus subtype H1N1 replication at doses below the cytotoxic dose. The ID₅₀ value of the TTO was found to be 0·0006% (v/v) and was much lower than its CD₅₀ (0·025% v/v). All the compounds were ineffective against polio 1, adeno 2, ECHO 9, Coxsackie B1, HSV-1 and HSV-2. None of the tested compounds showed virucidal activity. Only a slight virucidal effect was observed for TTO (0·125% v/v) against HSV-1 and HSV-2.
Conclusions:  These data show that TTO has an antiviral activity against influenza A/PR/8 virus subtype H1N1 and that antiviral activity has been principally attributed to terpinen-4-ol, the main active component.
Significance and Impact of the Study:  TTO should be a promising drug in the treatment of influenza virus infection.     

Virucidal effect of peppermint oil on the enveloped viruses herpes simplex virus type 1 and type 2 in vitro

The virucidal effect of peppermint oil, the essential oil of Mentha piperita, against herpes simplex virus was examined. The inhibitory activity against herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) was tested in vitro on RC-37 cells using a plaque reduction assay. The 50% inhibitory concentration (IC50) of peppermint oil for herpes simplex virus plaque formation was determined at 0.002% and 0.0008% for HSV-1 and HSV-2, respectively. Peppermint oil exhibited high levels of virucidal activity against HSV-1 and HSV-2 in viral suspension tests. At noncytotoxic concentrations of the oil, plaque formation was significantly reduced by 82% and 92% for HSV-1 and HSV-2, respectively. Higher concentrations of peppermint oil reduced viral titers of both herpesviruses by more than 90%. A clearly time-dependent activity could be demonstrated, after 3 h of incubation of herpes simplex virus with peppermint oil an antiviral activity of about 99% could be demonstrated. In order to determine the mode of antiviral action of the essential oil, peppermint oil was added at different times to the cells or viruses during infection. Both herpesviruses were significantly inhibited when herpes simplex virus was pretreated with the essential oil prior to adsorption. These results indicate that peppermint oil affected the virus before adsorption, but not after penetration into the host cell. Thus this essential oil is capable to exert a direct virucidal effect on HSV. Peppermint oil is also active against an acyclovir resistant strain of HSV-1 (HSV-1-ACV(res)), plaque formation was significantly reduced by 99%. Considering the lipophilic nature of the oil which enables it to penetrate the skin, peppermint oil might be suitable for topical therapeutic use as virucidal agent in recurrent herpes infection.     

Design and Synthesis of Acyclic Nucleoside Analogs with Chlorinated Imidazo[1,2-a]pyridine Bases

Abstract

A series of acyclic C-nucleoside analogs of 2,6-dichloro- and 2,6,7-trichloroimidazo[1,2-a]pyridine were synthesized and tested for antiviral activity. The appropriate hydroxymethyl-substituted heterocycles were treated successively with thionyl chloride, an appropriate nucleophile, then diisopropylethylamine to obtain the desired acyclic nucleoside analogs. These compounds were evaluated for activity against human cytomegalovirus and herpes simplex virus, type 1. Two of the dichloro analogs, but none of the trichloro analogs demonstrated slight antiviral activity (IC₅₀'s = 20–45 µM) at non-cytotoxic concentrations.     

Antiviral activity of south Brazilian medicinal plant extracts.

Brazilian plants are potential sources of useful edible and medicinal plants. Hydromethanolic extracts prepared from 54 medicinal plants used in folk medicine to treat infections were screened for antiviral properties against five different viruses (HSV-1, HSV-2, poliovirus type 2, adenovirus type 2 and VSV). Fifty-two percent of the plant extracts exhibited antiviral against one or more tested viruses. More specifically, 42.6% showed activity against HSV-1 (herpes simplex virus type 1), 42.6% against HSV-2 (herpes simplex virus type 2), 26% against poliovirus and 24% against VSV (vesicular stomatitis virus). None of the extracts was active against adenovirus. Trixis praestans (Vell.) Cabr. and Cunila spicata Benth. extracts were further characterized for antiviral activity.     

格尔德霉素抗病毒作用的相关基因研究

格尔德霉素(Geldanamycin,GA)作为一种苯醌安莎霉素类抗生素,能与热休克蛋白90特异性结合,具有广谱的抗病毒作用.为了从转录水平上研究GA抗病毒的分子机制,本研究以单纯疱疹病毒Ⅰ型(Herpes simplex vi-rus type 1,HSV-1)为对象,在确定药物有效抗病毒作用的基础上,采用基因芯片技术分析了在HeLa细胞中病毒感染和药物处理对细胞表达谱的影响,并筛选出GA抗病毒作用的可能相关基因.同时用半定量RT-PCR方法对GA诱导上调、HSV-1诱导下调的基因(ACTG1、RAN、SODl)以及GA诱导下调、HSV-1诱导上调的基因(HYALl)进行了验证.研究GA抗病毒作用对细胞表达谱的影响,有利于深入理解药物的抗病毒机制.     

Herpes simplex virus-1 entrapped in <Emphasis Type="Italic">Candida albicans</Emphasis> biofilm displays decreased sensitivity to antivirals and UVA1 laser treatment

Background

Recently, we published data suggesting a mutualistic relationship between HSV-1 and Candida. albicans; in particular: (a) HSV-1 infected macrophages are inhibited in their anti-Candida effector function and (b) Candida biofilm protects HSV-1 from inactivation. The present in vitro study is aimed at testing the effects of Candida biofilm on HSV-1 sensitivity to pharmacological and physical stress, such as antiviral drugs (acyclovir and foscarnet) and laser UVA1 irradiation. We also investigated whether fungus growth pattern, either sessile or planktonic, influences HSV-1 sensitivity to antivirals.

Methods

Mature Candida biofilms were exposed to HSV-1 and then irradiated with laser light (UVA1, 355 λ). In another set of experiments, mature Candida biofilm were co-cultured with HSV-1 infected VERO cells in the presence of different concentrations of acyclovir or foscarnet. In both protocols, controls unexposed to laser or drugs were included. The viral yield of treated and untreated samples was evaluated by end-point titration. To evaluate whether this protective effect might occur in relation with a different growth pattern, HSV-1 infected cells were co-cultured with either sessile or planktonic forms of Candida and then assessed for susceptibility to antiviral drugs.

Results

UVA1 irradiation caused a 2 Log reduction of virus yield in the control cultures whereas the reduction was only 1 Log with Candida biofilm, regardless to the laser dose applied to the experimental samples (50 or 100 J/cm²). The presence of biofilm increased the IC₉₀ from 18.4–25.6 J/cm². Acyclovir caused a 2.3 Log reduction of virus yield in the control cultures whereas with Candida biofilm the reduction was only 0.5 Log; foscarnet determined a reduction of 1.4 Log in the controls and 0.2 Log in biofilm cultures. Consequently, the ICs₅₀ for acyclovir and foscarnet increased by 4- and 12-folds, respectively, compared to controls. When HSV-1 was exposed to either sessile or planktonic fungal cells, the antiviral treatments caused approximately the same weak reduction of virus yield.

Conclusions

These data demonstrate that: (1) HSV-1 encompassed in Candida biofilm is protected from inactivation by physical (laser) and pharmacological (acyclovir or foscarnet) treatments; (2) the drug antiviral activity is reduced at a similar extent for both sessile or planktonic Candida.