Anti-bacterial activity of inorganic nanomaterials and their antimicrobial peptide conjugates against resistant and non-resistant pathogens

This review details the antimicrobial applications of inorganic nanomaterials of mostly metallic form, and the augmentation of activity by surface conjugation of peptide ligands. The review is subdivided into three main sections, of which the first describes the antimicrobial activity of inorganic nanomaterials against gram-positive, gram-negative and multidrug-resistant bacterial strains. The second section highlights the range of antimicrobial peptides and the drug resistance strategies employed by bacterial species to counter lethality. The final part discusses the role of antimicrobial peptide-decorated inorganic nanomaterials in the fight against bacterial strains that show resistance. General strategies for the preparation of antimicrobial peptides and their conjugation to nanomaterials are discussed, emphasizing the use of elemental and metallic oxide nanomaterials. Importantly, the permeation of antimicrobial peptides through the bacterial membrane is shown to aid the delivery of nanomaterials into bacterial cells. By judicious use of targeting ligands, the nanomaterial becomes able to differentiate between bacterial and mammalian cells and, thus, reduce side effects. Moreover, peptide conjugation to the surface of a nanomaterial will alter surface chemistry in ways that lead to reduction in toxicity and improvements in biocompatibility

Determination of the Relationship between Serum Calcium, Phosphor and Alkaline Phosphatase with Peripheral Giant Cell Granuloma in Iranian Patients

Peripheral giant cell granuloma (P.G.C.G) is an exophytic lesion with an approximate size of"n0.5-1.5 mm. It usually occurs on gingival and alveolar ridge of mandible particularly in molar and"npremolar region. The relation of serum calcium (Ca), Phosphor (P), and alkaline phosphatase (Alk) levels"nto P.G.C.G is yet controversial. In this descriptive study, 33 patients with P.G.C.G were chosen and"nserum Ca, P, and Alk levels compared with the normal range. In all patients the level of Ca was in the"nnormal range. Phosphor (P) was in the normal range in all patients over 17 years old and 80% under 17"nyears. The level of ALK in 75.8 percent of the patients over 17 years and 90% under 17 years was in the"nnormal range."nIn conclusion, no relationship was found between serum changes and P.G.C.G. It means P.G.C.G can be"ncompeletly independent lesions from serum changes

The importance of inducible clindamycin resistance in enterotoxin positive S. aureus isolated from clinical samples

"nBackground: Clindamycin is a suitable antibiotic for treatment of skin and soft tissue infections. Moreover, it can suppress toxin production in many pathogenic bacteria such as S. aureus. There are two mechanisms of resistance in this antibiotic. Constitutive resistance can be detected by standard disk diffusion method but in the case of inducible resistance, D-test should be carried out. The main aim of this study is to determine prevalence of clindamycin inducible resistance among methicillin resistant and susceptible isolates of S. aureus isolated from different clinical samples. "nMethods: A total of 87 clinical isolates from clinical samples were collected. Methicillin resistance was determined using standard disk diffusion method. Subsequently, D-test was carried out according to CLSI guideline. Presence of the sea gene (enterotoxin A) was detected by PCR using specific primers. "nResults: Out of 87 isolates, 18(20.7%) were clindamycin inducible resistant while constitutive resistance was detected among 21(24.1%) isolates. The 95% Confidence intervals for the proportion of inducible clindamycin resistance among clinical isolates of S. aureus was 12.2% to 29.2%. The inducible phenotype in MRSA isolates was more common than that of MSSA isolates (33.3% vs 5.1%).Significant differences were found between prevalence of inducible clindamycin resistance and type of infection (p=0.045). Importantly, there was a significant correlation between sea gene and the constitutive/inducible resistance (p<0.0001). "nConclusions: Due to the high prevalence of clindamycin inducible resistance among clinical isolates of S. aureus, we recommend D-test to avoid treatment failure

Comprehensive B Cell Phenotyping Profile for Chronic Graft-versus-Host Disease Diagnosis

Previous studies have reported single B cell-related chronic graft-versus-host disease diagnostic (cGVHD) bio-markers, such as B cell-activating factor (BAFF), CD21(low), and immature B cells, but research on the performance of biomarker combinations and the covariate effect of steroids is lacking. The primary objective of this study was to determine the most accurate combination of B cell populations using cell surface staining flow cytometry in an independent cohort of patients with cGVHD. Secondary objectives included assessing the effect of corticosteroid use at sample collection on the makeup and accuracy of the diagnostic panel and identifying the mechanism underlying low surface expression of BAFF receptor (BAFF-R) on B cells in cGVHD. Flow cytometry analysis was performed in an adult cohort of post-HCT patients with cGVHD onset (n = 44) and time-matched recipients without cGVHD (n = 63). We confirmed that the onset of cGVHD was associated with higher soluble BAFF (sBAFF) levels, elevated CD27(-)CD10(-)CD21(low) CD19(+) B cell and classical switched memory B cell counts, and reduced transitional and naive B cell counts. The highest single B cell population area under the receiver operating characteristic (ROC) curve (AUC) was .72 for transitional type 1 CD21(low) B cells. We also showed a significant inverse relationship between sBAFF and surface BAFF-R expression caused by sBAFF modulation of BAFF-R. Steroid use at sample collection influenced the significance of the sBAFF:B cell ratio, naive and marginal zone-like B cells. The optimal combination of B cell subsets most significantly associated with cGVHD onset with or without concurrent corticosteroid use resulted in ROC AUCs of .87 and .84, respectively. Transitional and CD21(low) B cells were the only populations present in both panels; however, analyzing only these populations resulted in ROC AUCs of .79 and .78, respectively. This suggests that the inclusion of other populations and use of different panels depending on steroid use is necessary to achieve better accuracy. sBAFF was not a component of either panel. These novel B cell profiles could be tested prospectively in patients post-HSCT and could lead to focused mechanistic studies. (C) 2018 American Society for Blood and Marrow Transplantation

Arginase activity in pathogenic and non-pathogenic species of <i>Leishmania</i> parasites

<div><p>Proliferation of <i>Leishmania</i> (<i>L</i>.) parasites depends on polyamine availability, which can be generated by the L-arginine catabolism and the enzymatic activity of arginase (ARG) of the parasites and of the mammalian hosts. In the present study, we characterized and compared the arginase (<i>arg</i>) genes from pathogenic <i>L</i>. <i>major</i> and <i>L</i>. <i>tropica</i> and from non-pathogenic <i>L</i>. <i>tarentolae</i>. We quantified the level of the ARG activity in promastigotes and macrophages infected with pathogenic <i>L</i>. <i>major</i> and <i>L</i>. <i>tropica</i> and non-pathogenic <i>L</i>. <i>tarentolae</i> amastigotes. The ARG's amino acid sequences of the pathogenic and non-pathogenic <i>Leishmania</i> demonstrated virtually 98.6% and 88% identities with the reference <i>L</i>. <i>major</i> Friedlin ARG. Higher ARG activity was observed in all pathogenic promastigotes as compared to non-pathogenic <i>L</i>. <i>tarentolae</i>. <i>In vitro</i> infection of human macrophage cell line (THP1) with pathogenic and non-pathogenic <i>Leishmania</i> spp. resulted in increased ARG activities in the infected macrophages. The ARG activities present <i>in vivo</i> were assessed in susceptible BALB/c and resistant C57BL/6 mice infected with <i>L</i>. <i>major</i>, <i>L</i>. <i>tropica</i> and <i>L</i>. <i>tarentolae</i>. We demonstrated that during the development of the infection, ARG is induced in both strains of mice infected with pathogenic <i>Leishmania</i>. However, in <i>L</i>. <i>major</i> infected BALB/c mice, the induction of ARG and parasite load increased simultaneously according to the time course of infection, whereas in C57BL/6 mice, the enzyme is upregulated solely during the period of footpad swelling. In <i>L</i>. <i>tropica</i> infected mice, the footpads' swellings were slow to develop and demonstrated minimal cutaneous pathology and ARG activity. In contrast, ARG activity was undetectable in mice inoculated with the non-pathogenic <i>L</i>. <i>tarentolae</i>. Our data suggest that infection by <i>Leishmania</i> parasites can increase ARG activity of the host and provides essential polyamines for parasite salvage and its replication. Moreover, the ARG of <i>Leishmania</i> is vital for parasite proliferation and required for infection in mice. ARG activity can be used as one of the main marker of the disease severity.</p></div

Human Neutrophil Peptide 1 as immunotherapeutic agent against <i>Leishmania</i> infected BALB/c mice

<div><p>Human Neutrophil Peptide 1 (HNP1) produced by neutrophils, is a well-known antimicrobial peptide which plays a role both in innate as well as in adaptive immunity and is under intensive investigation as a potential therapeutic agent. Previous <i>in vitro</i> experiments have indicated the leishmaniacidal effect of recombinant HNP1 on <i>Leishmania major</i> (<i>L</i>. <i>major</i>) promastigotes and amastigotes. In the current study, we further extended the idea to explore the remedial effect of HNP1 in the two modalities of peptide therapy (folded HNP1) and gene therapy in <i>L</i>. <i>major</i> infected BALB/c mice. To this end, mice in five different groups received synthetic folded HNP1 (G1), pcDNA-HNP1-EGFP (G2), pcDNA-EGFP (G3), Amphotericin B (G4) and PBS (G5), which was started three weeks after infection for three consecutive weeks. Footpad swelling was monitored weekly and a day after the therapy ended, IFN-γ, IL-4, IL-10, IL-6 and nitric oxide produced by splenocytes were analyzed together with the parasite load in draining lymph nodes. Arginase activity and dermal histopathological changes were also analyzed in the infected footpads. We demonstrated that both therapeutic approaches effectively induced Th1 polarization and restricted parasite burden. It can control disease progression in contrast to non-treated groups. However, pcDNA-HNP1-EGFP is more promising in respect to parasite control than folded HNP1, but less effective than AmB treatment. We concluded with the call for a future approach, that is, a DNA-based expression of HNP1 combined with AmB as it can improve the leishmaniacidal efficacy.</p></div

Lesion development, ARG activity and parasite burden in <i>L</i>. <i>major</i> infected mice in footpads and draining lymph nodes.

<p>Groups of susceptible BALB/c and resistant C57BL/6 mice were infected with 2×10⁶ metacyclic <i>L</i>. <i>major</i> promastigotes in the left hind footpad. (A) The lesion size was monitored by measuring the increase in footpad thickness and width weekly by using a caliper. At various times after infection (ending at 10 week) mice were sacrificed and ARG activity was determined in (B) footpads and (D) lymph nodes. (C) Parasite number was quantified in draining lymph nodes at 1, 5 and 10 weeks after infection. Data reported are those of duplicate samples, and the experimental procedure was repeated at least two times with similar outcomes. Error bars are SD (**p≤ 0.01, ****p≤ 0.001 and *****p≤ 0.0001).</p

Correlation analysis between parasite numbers and ARG activity in infected draining lymph nodes (LN).

<p>At various times after infection (A) BALB/c and (B) C57BL/6 mice infected with pathogenic (<i>L</i>. <i>major</i>: 2×10⁶ parasites/ml and <i>L</i>. <i>tropica</i>: 2×10⁷ parasites/ml) and non-pathogenic <i>Leishmania</i> (<i>L</i>. <i>tarentolae</i>: 2×10⁷ parasites/ml<i>)</i> promastigotes were sacrificed, and parasite numbers as well as ARG activity in the draining LNs was determined. Data reported are those of duplicate samples, and the experimental procedure was repeated at least two times with similar outcomes. Error bars are SD (**p≤ 0.01, ****p≤ 0.001 and *****p≤ 0.0001) (W: Week).</p

Blast alignment of sequenced <i>Leishmania</i> spp. ARG and three retrieved reference <i>Leishmania</i> ARG sequences of the GenBank in DNA and amino acids level.

<p>Blast alignment of sequenced <i>Leishmania</i> spp. ARG and three retrieved reference <i>Leishmania</i> ARG sequences of the GenBank in DNA and amino acids level.</p