Background

Circumcision is associated with significant reductions in HIV, HSV-2 and HPV infections among men and significant reductions in bacterial vaginosis among their female partners.

Methodology/Principal Findings

We assessed the penile (coronal sulci) microbiota in 12 HIV-negative Ugandan men before and after circumcision. Microbiota were characterized using sequence-tagged 16S rRNA gene pyrosequencing targeting the V3–V4 hypervariable regions. Taxonomic classification was performed using the RDP Naïve Bayesian Classifier. Among the 42 unique bacterial families identified, Pseudomonadaceae and Oxalobactericeae were the most abundant irrespective of circumcision status. Circumcision was associated with a significant change in the overall microbiota (PerMANOVA p  = 0.007) and with a significant decrease in putative anaerobic bacterial families (Wilcoxon Signed-Rank test p  = 0.014). Specifically, two families—Clostridiales Family XI ( p  = 0.006) and Prevotellaceae ( p  = 0.006)—were uniquely abundant before circumcision. Within these families we identified a number of anaerobic genera previously associated with bacterial vaginosis including: Anaerococcus spp. , Finegoldia spp. , Peptoniphilus spp. , and Prevotella spp.

Conclusions/Significance

The anoxic microenvironment of the subpreputial space may support pro-inflammatory anaerobes that can activate Langerhans cells to present HIV to CD4 cells in draining lymph nodes. Thus, the reduction in putative anaerobic bacteria after circumcision may play a role in protection from HIV and other sexually transmitted diseases.

Fungi, such as Candida spp., are commonly found on the skin and at mucosal surfaces. Yet, they rarely cause invasive infections in immunocompetent individuals, an observation reflecting the ability of our innate immune system to control potentially invasive microbes found at biological boundaries. Antimicrobial proteins and peptides are becoming increasingly recognized as important effectors of innate immunity. This is illustrated further by the present investigation, demonstrating a novel antifungal role of histidine-rich glycoprotein (HRG), an abundant and multimodular plasma protein. HRG bound to Candida cells, and induced breaks in the cell walls of the organisms. Correspondingly, HRG preferentially lysed ergosterol-containing liposomes but not cholesterol-containing ones, indicating a specificity for fungal versus other types of eukaryotic membranes. Both antifungal and membrane-rupturing activities of HRG were enhanced at low pH, and mapped to the histidine-rich region of the protein. Ex vivo , HRG-containing plasma as well as fibrin clots exerted antifungal effects. In vivo , Hrg ^−/− mice were susceptible to infection by C. albicans , in contrast to wild-type mice, which were highly resistant to infection. The results demonstrate a key and previously unknown antifungal role of HRG in innate immunity.

Background

Acne vulgaris afflicts more than fifty million people in the United State and the severity of this disorder is associated with the immune response to Propionibacterium acnes (P. acnes) . Systemic therapies for acne target P. acnes using antibiotics, or target the follicle with retinoids such as isotretinoin. The latter systemic treatment is highly effective but also carries a risk of side effects including immune imbalance, hyperlipidemia, and teratogenicity. Despite substantial research into potential new therapies for this common disease, vaccines against acne vulgaris are not yet available.

Methods and Findings

Here we create an acne vaccine targeting a cell wall-anchored sialidase of P. acnes. The importance of sialidase to disease pathogenesis is shown by treatment of a human sebocyte cell line with recombinant sialidase that increased susceptibility to P. acnes cytotoxicity and adhesion. Mice immunized with sialidase elicit a detectable antibody; the anti-sialidase serum effectively neutralized the cytotoxicity of P. acnes in vitro and P. acnes -induced interleukin-8 (IL-8) production in human sebocytes. Furthermore, the sialidase-immunized mice provided protective immunity against P. acnes in vivo as this treatment blocked an increase in ear thickness and release of pro-inflammatory macrophage inflammatory protein (MIP-2) cytokine.

Conclusions

Results indicated that acne vaccines open novel therapeutic avenues for acne vulgaris and other P. acnes -associated diseases.

Background

Minor capsid protein L2 performs an indispensable but uncharacterized role in human papillomavirus infections. A neutralizing B cell epitope has recently been mapped to the N-terminus of HPV16 L2, residues 17–36, and exposure of this region of L2 has been implicated in translocation of incoming virions from the endo/lysosomal compartment to the cellular cytoplasm. Here we examine the redox state of Cys22 and Cys28 two highly conserved cysteines located within this epitope. We also investigate the infectivity of virions containing L2 single and double cysteine point mutants.

Methodology and Principal Findings

Denaturing/non-reducing gel analysis and thiol labeling experiments of wild type and cysteine mutant HPV16 virion particles strongly support the existence of a buried intramolecular C22–C28 disulfide bond. The disulfide was confirmed by tandem mass spectrometry of L2 protein from non-reduced virions. Single C22S and C28S and the double C22/28S mutants were non-infectious but had no apparent defects in cell binding, endocytosis, or trafficking to lysosomes by 8 h post infection. During infection with L2 mutant particles, there was a marked decrease in L2 levels compared to wild type L2-containing virions, suggesting a failure of mutant L2/genome complexes to exit the endo/lysosomal compartment.

Conclusions and Significance

L2 residues C22 and C28 are bound as an intramolecular disulfide bond in HPV16 virions and are necessary for infectivity. Previous work has suggested that the furin-dependent exposure of the 17–36 epitope and subsequent interaction of this region with an unknown receptor is necessary for egress from the endo/lysosomal compartment and infection. Identification of the C22–C28 disulfide suggests that reduction of this disufide bond may be necessary for exposure of 17–36 and HPV16 infection.

Staphylococcus aureus ( SA ) is a leading cause of a diverse spectrum of bacterial diseases, including abscesses. Nitric oxide (NO) is a critical component of the natural host defense against pathogens such as SA , but its therapeutic applications have been limited by a lack of effective delivery options. We tested the efficacy of a NO-releasing nanoparticle system (NO-np) in methicillin-resistant SA (MR SA ) abscesses in mice. The results show that the NO-np exert antimicrobial activity against MR SA in vitro and in abscesses. Topical or intradermal NO-np treatment of abscesses reduces the involved area and bacterial load while improving skin architecture. Notably, we evaluated pro- and anti-inflammatory cytokines that are involved in immunomodulation and wound healing, revealing that NO-np lead to a reduction in angiogenesis preventing bacterial dissemination from abscesses. These data suggest that NO-np may be useful therapeutics for microbial abscesses.

Infection of the mammalian host by the parasitic helminth Schistosoma mansoni is accompanied by the release of excretory/secretory molecules (ES) from cercariae which aid penetration of the skin. These ES molecules are potent stimulants of innate immune cells leading to activation of acquired immunity. At present however, it is not known which cells take up parasite antigen, nor its intracellular fate. Here, we develop a technique to label live infectious cercariae which permits the imaging of released antigens into macrophages (MΦ) and dendritic cells (DCs) both in vitro and in vivo . The amine reactive tracer CFDA-SE was used to efficiently label the acetabular gland contents of cercariae which are released upon skin penetration. These ES products, termed ‘0-3hRP’, were phagocytosed by MHC-II ⁺ cells in a Ca ⁺ and actin-dependent manner. Imaging of a labelled cercaria as it penetrates the host skin over 2 hours reveals the progressive release of ES material. Recovery of cells from the skin shows that CFDA-SE labelled ES was initially (3 hrs) taken up by Gr1 ⁺ MHC-II ⁻ neutrophils, followed (24 hrs) by skin-derived F4/80 ⁺ MHC-II ^lo MΦ and CD11c ⁺ MHC-II ^hi DC. Subsequently (48 hrs), MΦ and DC positive for CFDA-SE were detected in the skin-draining lymph nodes reflecting the time taken for antigen-laden cells to reach sites of immune priming. Comparison of in vitro -derived MΦ and DC revealed that MΦ were slower to process 0-3hRP, released higher quantities of IL-10, and expressed a greater quantity of arginase-1 transcript. Combined, our observations on differential uptake of cercarial ES by MΦ and DC suggest the development of a dynamic but ultimately balanced response that can be potentially pushed towards immune priming (via DC) or immune regulation (via MΦ).

Background

The evolutionary history of several genes of the bacterial pathogen Streptococcus pyogenes strongly suggests an origin in another species, acquired via replacement of the counterpart gene (ortholog) following a recombination event. An example of orthologous gene replacement is provided by the nra/rofA locus, which encodes a key regulator of pilus gene transcription. Of biological importance is the previous finding that the presence of the nra - and rofA -lineage alleles, which are ∼35% divergent, correlates strongly with genetic markers for streptococcal infection at different tissue sites in the human host (skin, throat).

Methodology/Principal Findings

In this report, the impact of orthologous gene replacement targeting the nra/rofA locus is experimentally addressed. Replacement of the native nra -lineage allele with a rofA -lineage allele, plus their respective upstream regions, preserved the polarity of Nra effects on pilus gene transcription (i.e., activation) in the skin strain Alab49. Increased pilus gene transcription in the rofA chimera correlated with a higher rate of bacterial growth at the skin. The transcriptional regulator MsmR, which represses nra and pilus gene transcription in the Alab49 parent strain, has a slight activating effect on pilus gene expression in the rofA chimera construct.

Conclusions/Significance

Data show that exchange of orthologous forms of a regulatory gene is stable and robust, and pathogenicity is preserved. Yet, new phenotypes may also be introduced by altering the circuitry within a complex transcriptional regulatory network. It is proposed that orthologous gene replacement via interspecies exchange is an important mechanism in the evolution of highly recombining bacteria such as S. pyogenes .

Background

Malathion 0.5% has been the most prescribed pediculicide in the United Kingdom for around 10 years, and is widely used in Europe and North America. Anecdotal reports suggest malathion treatments are less effective than formerly, but this has not been confirmed clinically. This study was designed to determine whether malathion is still effective and if 4% dimeticone lotion is a more effective treatment for head louse infestation.

Methodology/Principal Findings

We designed this study as an assessor blinded, randomised, controlled, parallel group trial involving 58 children and 15 adults with active head louse infestation. Each participant received two applications 7 days apart of either 4% dimeticone lotion, applied for 8 hours or overnight, or 0.5% malathion liquid applied for 12 hours or overnight. All treatment and check-up visits were conducted in participants' homes. Cure of infestation was defined as no evidence of head lice after the second treatment. Some people were found free from lice but later reinfested. Worst case, intention to treat, analysis found dimeticone was significantly more effective than malathion, with 30/43 (69.8%) participants cured using dimeticone compared with 10/30 (33.3%) using malathion (p<0.01, difference 36.4%, 95% confidence interval 14.7% to 58.2%). Per protocol analysis showed cure rates of 30/39 (76.9%) and 10/29 (34.5%) respectively. Irritant reactions were observed in only two participants, both treated with malathion.

Conclusions/Significance

We concluded that, although malathion liquid is still effective for some people, dimeticone lotion offers a significantly more effective alternative treatment for most people.

Trial Registration

Controlled-Trials.comISRCTN47755726

Backgound

Human scabies is a debilitating skin disease caused by the “itch mite” Sarcoptes scabiei . Ordinary scabies is commonly treated with topical creams such as permethrin, while crusted scabies is treated with topical creams in combination with oral ivermectin. Recent reports of acaricide tolerance in scabies endemic communities in Northern Australia have prompted efforts to better understand resistance mechanisms and to identify potential new acaricides. In this study, we screened three essential oils and four pure compounds based on eugenol for acaricidal properties.

Methodology/Principal Findings

Contact bioassays were performed using live permethrin-sensitive S. scabiei var suis mites harvested from pigs and permethrin-resistant S. scabiei var canis mites harvested from rabbits. Results of bioassays showed that clove oil was highly toxic against scabies mites. Nutmeg oil had moderate toxicity and ylang ylang oil was the least toxic. Eugenol, a major component of clove oil and its analogues –acetyleugenol and isoeugenol, demonstrated levels of toxicity comparable to benzyl benzoate, the positive control acaricide, killing mites within an hour of contact.

Conclusions

The acaricidal properties demonstrated by eugenol and its analogues show promise as leads for future development of alternative topical acaricides to treat scabies.