Non-invasive molecular biomarkers for monitoring solid organ transplantation: A comprehensive overview.

Solid organ transplantation is a life-saving intervention for individuals with end-stage organ failure. Despite the effectiveness of immunosuppressive therapy, the risk of graft rejection persists in all viable transplants between individuals. The risk of rejection may vary depending on the degree of compatibility between the donor and recipient for both human leucocyte antigen (HLA) and non-HLA gene-encoded products. Monitoring the status of the allograft is a critical aspect of post-transplant management, with invasive biopsies being the standard of care for detecting rejection. Non-invasive biomarkers are increasingly being recognized as valuable tools for aiding in the detection of graft rejection, monitoring graft status and evaluating the efficacy of immunosuppressive therapy. Here, we focus on the importance of molecular biomarkers in solid organ transplantation and their potential role in clinical practice. Conventional molecular biomarkers used in transplantation include HLA typing, detection of anti-HLA antibodies, killer cell immunoglobulin-like receptor genotypes, and anti-MHC class 1-related chain A antibodies, which are important for assessing the compatibility of the donor and recipient. Emerging molecular biomarkers include the detection of donor-derived cell-free DNA, microRNAs (regulation of gene expression), exosomes (small vesicles secreted by cells), and kidney solid organ response test, in the recipient's blood for early signs of rejection. This review highlights the strengths and limitations of these molecular biomarkers and their potential role in improving transplant outcomes.

Microbiota and Gut-Liver Axis: An Unbreakable Bond?

The gut microbiota, amounting to approximately 100 trillion (1014) microbes represents a genetic repertoire that is bigger than the human genome itself. Evidence on bidirectional interplay between human and microbial genes is mounting. Microbiota probably play vital roles in diverse aspects of normal human metabolism, such as digestion, immune modulation, and gut endocrine function, as well as in the genesis and progression of many human diseases. Indeed, the gut microbiota has been most closely linked to various chronic ailments affecting the liver, although concrete scientific data are sparse. In this narrative review, we initially discuss the basic epidemiology of gut microbiota and the factors influencing their initial formation in the gut. Subsequently, we delve into the gut-liver axis and the evidence regarding the link between gut microbiota and the genesis or progression of various liver diseases. Finally, we summarise the recent research on plausible ways to modulate the gut microbiota to alter the natural history of liver disease.

An update on possible alternative therapeutics for future periodontal disease management.

Periodontitis is an inflammatory disease caused by microbial infections of the gum. At an advanced stage, periodontitis can even destroy the alveolar bone. Fusobacterium nucleatum, Prevotella intermedia, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Capnocytophaga gingivalis, and Pr. nigrescens are the major pathogens in periodontitis. Scaling and root planning are used together with local or systemic antibiotics to treat periodontitis. The difficulty in complete eradication of periodontal pathogens frequently leads to the relapse of the disease. As not many new antibiotics are available in the market, many researchers are now focusing on developing alternative strategies against periodontal microbes. This review provides an overview of the possible use of bacteriophages, lysins, honey, plant extracts, metallic salts, nanoparticles, and vaccines as alternative therapeutic agents against periodontal infections. The information provided here could help in designing alternative therapeutics for the treatment of periodontal infections.

Exploring alternative strategies for Staphylococcus aureus nasal decolonization: insights from preclinical studies.

Nasal decolonization of Staphylococcus aureus with the antibiotic mupirocin is a common clinical practice before complex surgical procedures, to prevent hospital acquired infections. However, widespread use of mupirocin has led to the development of resistant S. aureus strains and there is a limited scope for developing new antibiotics for S. aureus nasal decolonization. It is therefore necessary to develop alternative and nonantibiotic nasal decolonization methods. In this review, we broadly discussed the effectiveness of different nonantibiotic antimicrobial agents that are currently not in clinical practice, but are experimentally proved to be efficacious in promoting S. aureus nasal decolonization. These include lytic bacteriophages, bacteriolytic enzymes, tea tree oil, apple vinegar, and antimicrobial peptides. We have also discussed the possibility of using photodynamic therapy for S. aureus nasal decolonization. This article highlights the importance of further large scale clinical studies for selecting the most suitable and alternative nasal decolonizing agent.

Protective efficacy of Alum adjuvanted Amidase protein vaccine against Staphylococcus aureus infection in multiple mouse models.

AIMS: Staphylococcus aureus is an opportunistic pathogen of humans. No commercial vaccine is available to combat S. aureus infections. In this study, we have investigated the protective immune response generated by S. aureus non-covalently associated cell wall surface protein N-acetylmuramoyl-L-alanine amidase (AM) in combination with Alum (Al) and heat-killed S. aureus (hkSA) using murine models. METHODS AND RESULTS: BALB/c mice were immunized with increasing concentrations of AM antigen or hkSA to determine their optimum concentration for vaccination. Fifty micrograms of AM and hkSA each were found to generate maximum anti-AM IgG antibody production. BALB/c mice were immunized next with 50 µg of AM, 50 µg of hKSA and 1 mg Al vaccine formulation. Vaccine efficacy was validated by challenging immunized BALB/c mice with S. aureus Newman and three clinical methicillin-resistant S. aureus strains. AM-hkSA-Al-immunized mice generated high anti-AM IgG antibody response with IgG1 and IgG2b as the predominant immunoglobulin subtypes. Increased survival (60%-90%) with decreased clinical disease symptoms was observed in the vaccinated BALB/c mice group. A significantly lower bacterial load and decreased kidney abscess formation was observed following the challenge with S. aureus in the vaccinated BALB/c mice group. Furthermore, the efficacy of AM-hkSA-Al vaccine was also validated using C57 BL/6 and Swiss albino mice. CONCLUSIONS: Using murine infection models, we have demonstrated that AM-hkSA-Al vaccine would be effective in preventing S. aureus infections. SIGNIFICANCE AND IMPACT OF STUDY: AM-hkSA-Al vaccine elicited strong immune response and may be considered for future vaccine design against S. aureus infections.

Describing the Clinical and Laboratory Features and HLA-B Pattern of Adult-Onset Idiopathic Autoimmune Uveitis at a Tertiary Hospital in South India: A Cross-Sectional Study.

INTRODUCTION: There is a scarcity of information available on clinical and laboratory features of adult-onset idiopathic autoimmune uveitis. Therefore, we conducted a single centre descriptive cross-sectional study. Patients and Methods. A chart review of all patients with idiopathic autoimmune uveitis with onset after 18 years of age who were referred to the rheumatology department between January 2017 and December 2018 was performed. Their clinical features, demographic features, and HLA-B genotypes were documented and described. RESULTS: Out of 210 patients referred to rheumatology, 66 were found to have uveitis, and 16 of these had an adult-onset idiopathic autoimmune uveitis. Apart from a slight female preponderance (62.5%), our patients were characterized by a high proportion of panuveitis (4 out of 16, i.e., 25%). There was an increased frequency of occurrence of synechiae (5 out of 16, i.e., 31.3%), retinal vasculitis (4 out of 16, i.e., 25%), optic disc edema (3 out of 16, i.e., 18.8%), and cystoid macular edema (seen in 2 patients, i.e., 12.5%). These features correlated with the anatomical subtypes. Retinal vasculitis and optic disc edema present in three fourth of all panuveitis cases were the most prominent features. The odds of finding HLA-B∗35 in retinal vasculitis were 33 times higher than odds of finding it in idiopathic autoimmune uveitis patients not having retinal vasculitis (OR 33; 95% CI 1.6-698). CONCLUSION: Idiopathic autoimmune uveitis in our patients is characterized by a high frequency of panuveitis and retinal vasculitis, and complications with a probable association between HLA-B∗35 and retinal vasculitis.

Eosinophilic Meningitis and Intraocular Infection Caused by Dirofilaria sp. Genotype Hongkong.

Eosinophilic meningitis caused by human diroflarial infection is rare. We report a case of eosinophilic meningitis and concomitant intraocular dirofilarial infection in India. Sequencing of the mitochondrial genome identified the worm as Dirofilaria sp. genotype Hongkong, a close relative of D. repens nematodes.

Prevalence of high-risk HPV and its genotypes-Implications in the choice of prophylactic HPV vaccine.

The prevalence of human papillomavirus (HPV) types varies geographically between various countries and different parts of the same country. The efficacy of the HPV vaccines is dependent on the prevalent HPV types. Here, we have studied the prevalence of high-risk HPV (hrHPV) and its genotypes in women in our population. Cervical samples of 2443 women were screened for the presence of hrHPV using the careHPV system. To determine the HPV genotypes, viral DNA was isolated from the hrHPV-positive samples, nested PCR was used to amplify the L1 hypervariable region, and was subjected to Sanger sequencing. The prevalence of hrHPV was found to be 2%. HPV16 (52%), HPV33 (40%), HPV18 (4%), HPV31 (2%), and HPV66 (2%) genotypes were found in this study. In Kerala, HPV16 and HPV33 genotypes were found to be significantly higher compared with the other HPV types detected. As the bivalent (Cervarix) and quadrivalent (Gardasil-4) vaccines offer limited cross-protection against HPV33, nonavalent (Gardasil 9) vaccine would be more effective in preventing cervical carcinoma in Kerala.

An update on recent developments in the prevention and treatment of Staphylococcus aureus biofilms.

Staphylococcus aureus (S. aureus) readily forms biofilms on prosthetic devices such as the pacemakers, heart valves, orthopaedic implants, and indwelling catheters. Its biofilms are recalcitrant to antibiotic therapy and pose a serious burden in the healthcare setting as they drastically increase the treatment cost and morbidity of the patient. Prevention and treatment of staphylococcal biofilms has therefore been an area of active research for the past two decades. While catheters coated with different antiseptics and antibiotics capable of preventing S. aureus biofilm formation have been developed, an effective therapy for the dispersal and treatment of established staphylococcal biofilms is not yet available. Hence, many studies have focused on developing novel therapeutic strategies that can tackle established S. aureus biofilm associated infections. This has led to the identification of different phytochemicals (e.g., tannic acid, ellagic acid, xanthohumol etc), enzymes (e.g., Dnases, lysostaphin, α-amylase, hyaluronidase and proteases etc.), sulfahydrl compounds (e.g., dithiothreitol, 2-mercaptoethanol), nanoparticles (e.g., gold, silver, iron, copper and selenium), phage cocktails, antibodies and metal chelators. Apart from the conventional techniques, the therapeutic effects of ultra sound, shock waves and photodynamic therapy for treating S. aureus biofilms are also being investigated. Clinical validation of these studies will equip the medical field with alternate preventive and treatment methods against staphylococcal biofilm infections. This review provides recent updates on the preventive and therapeutic strategies explored to eradicate staphylococcal biofilm formation and related infections.

Impact of cell wall peptidoglycan O-acetylation on the pathogenesis of Staphylococcus aureus in septic arthritis.

Staphylococcus aureus (S. aureus) is one of the most common pathogen causing septic arthritis. To colonize the joints and establish septic arthritis this bacterium needs to resist the host innate immune responses. Lysozyme secreted by neutrophils and macrophages is an important defense protein present in the joint synovial fluids. S. aureus is known to be resistant to lysozyme due to its peptidoglycan modification by O-acetylation of N-acetyl muramic acid. In this study we have investigated the role of O-acetylated peptidoglycan in septic arthritis. Using mouse models for both local and hematogenous S. aureus arthritis we compared the onset and progress of the disease induced by O-acetyl transferase mutant and the parenteral wild type SA113 strain. The disease progression was assessed by observing the clinical parameters including body weight, arthritis, and functionality of the affected limbs. Further X-ray and histopathological examinations were performed to monitor the synovitis and bone damage. In local S. aureus arthritis model, mice inoculated with the ΔoatA strain developed milder disease (in terms of knee swelling, motor and movement functionality) compared to mice inoculated with the wild type SA113 strain. X-ray and histopathological data revealed that ΔoatA infected mice knee joints had significantly lesser joint destruction, which was accompanied by reduced bacterial load in knee joints. Similarly, in hematogenous S. aureus arthritis model, ΔoatA mutant strain induced significantly less severe clinical septic arthritis compared to its parental strain, which is in accordance with radiological findings. Our data indicate that peptidoglycan O-acetylation plays an important role in S. aureus mediated septic arthritis.

First two bilateral hand transplantations in India (Part 4): Immediate post-operative care, immunosuppression protocol and monitoring.

INTRODUCTION: Being able to counter immune-mediated rejection has for decades been the single largest obstacle for the progress of vascular composite allotransplantation (VCA). The human immune system performs the key role of differentiating the 'self ' from the 'non-self '. This, although is quintessential to eliminate or resist infections, also resists the acceptance of an allograft which it promptly recognises as 'non-self'. MATERIALS AND METHODS: Pre-operative evaluation of the recipient evaluation included immunological assessment in the form of panel reactive antibodies (PRA), human leucocyte antigen (HLA) typing, donor-specific antibody detection assays (DSA) and complement-dependent cytotoxicity assays (CDC). Induction immunosuppression was by thymoglobulin and the maintenance by the standard triple-drug therapy. RESULTS: Both the recipients were managed by the standard triple drug therapy and have had only minor episodes of rejections thus far which have been managed appropriately. DISCUSSION: Induction immunosuppression was by thymoglobulin and the maintenance by the standard triple-drug therapy. Various groups have tried various other formulations and regimes as well. CONCLUSION: A comprehensive plan has to be drawn up for immunological screening, selection and the post-operative immunosuppressant usage. The ultimate goal of these immunosuppression modalities is to achieve a state of donor-specific tolerance.

Antibiotic resistance in Pseudomonas aeruginosa and alternative therapeutic options.

Pseudomonas aeruginosa is a leading cause of nosocomial infections and is responsible for ∼10% of all hospital-acquired infections worldwide. It continues to pose a therapeutic challenge because of the high rate of morbidity and mortality associated with it and the possibility of development of drug resistance during therapy. Standard antibiotic regimes against P. aeruginosa are increasingly becoming ineffective due to the rise in drug resistance. With the scope for developing new antibiotics being limited, alternative treatment options are gaining more and more attention. A number of recent studies reported complementary and alternative treatment options to combat P. aeruginosa infections. Quorum sensing inhibitors, phages, probiotics, anti-microbial peptides, vaccine antigens and antimicrobial nanoparticles have the potential to act against drug resistant strains. Unfortunately, most studies considering alternative treatment options are still confined in the pre-clinical stages, although some of these findings have tremendous potential to be turned into valuable therapeutics. This review is intended to raise awareness of several novel approaches that can be considered further for combating drug resistant P. aeruginosa infections.

Impact of Staphylococcus aureus on pathogenesis in polymicrobial infections.

Polymicrobial infections involving Staphylococcus aureus exhibit enhanced disease severity and morbidity. We reviewed the nature of polymicrobial interactions between S. aureus and other bacterial, fungal, and viral cocolonizers. Microbes that were frequently recovered from the infection site with S. aureus are Haemophilus influenzae, Enterococcus faecalis, Pseudomonas aeruginosa, Streptococcus pneumoniae, Corynebacterium sp., Lactobacillus sp., Candida albicans, and influenza virus. Detailed analyses of several in vitro and in vivo observations demonstrate that S. aureus exhibits cooperative relations with C. albicans, E. faecalis, H. influenzae, and influenza virus and competitive relations with P. aeruginosa, Streptococcus pneumoniae, Lactobacillus sp., and Corynebacterium sp. Interactions of both types influence changes in S. aureus that alter its characteristics in terms of colony formation, protein expression, pathogenicity, and antibiotic susceptibility.

BMPR2 mutation and clinical response to imatinib in a case of heritable pulmonary arterial hypertension.

Bone morphogenetic protein receptor 2 (BMPR2) mutation is the most common gene mutation implicated in the pathogenesis of pulmonary arterial hypertension (PAH). We describe, for the first time, an excellent clinical response to tyrosine kinase inhibitor imatinib in a patient with heritable PAH from BMPR2 mutation.

Efficacy of Lysostaphin functionalized silicon catheter for the prevention of Staphylococcus aureus biofilm.

Staphylococcus aureus readily forms biofilms on tissue and indwelling catheter surfaces. These biofilms are resistant to antibiotics. Consequently, effective prevention and treatment strategies against staphylococcal biofilms are actively being pursued over the past two decades. One of the proposed strategies involve the incorporation of antibiotics and antiseptics into catheters, however, a persistent concern regarding the possible emergence of antimicrobial resistance is associated with these medical devices. In this study, we developed two types of silicone catheters: one with Lysostaphin (Lst) adsorbed onto the surface, and the other with Lst functionalized on the surface. To confirm the presence of Lst protein on the catheter surface, we conducted FTIR-ATR and SEM-EDS analysis. Both catheters exhibited hemocompatibility, biocompatibility, and demonstrated antimicrobial and biofilm prevention activities against both methicillin-sensitive and resistant strains of S. aureus. Furthermore, the silicone catheters that were surface-functionalized with Lst showed substantially better and more persistent anti-biofilm effects when compared to the catheters where Lst was surface-adsorbed, both under in vitro static and flow conditions, as well as in vivo in BALB/c mice. These results indicate that surface-functionalized Lst catheters have the potential to serve as a promising new medical device for preventing S. aureus biofilm infections in humans.

Drug Susceptibility and Mutation Profiles in Mycobacterium tuberculosis Isolates from a Tertiary Care Hospital in Kerala, India.

The rising prevalence of drug-resistant Mycobacterium tuberculosis (MTB) strains poses a significant challenge to global tuberculosis (TB) control efforts. This study aimed to analyze drug resistance patterns and investigate the molecular characteristics of 193 MTB clinical isolates to shed light on the mechanisms of drug resistance. Of the 193 MTB clinical isolates, 28.5% (n = 53) exhibited mono-drug or multidrug resistance. Pyrazinamide mono-drug resistance (PZAr) was the most prevalent (17%, n = 33), followed by isoniazid mono-drug resistance (3.6%, n = 7). Rifampicin resistance was associated with mutations in the rpoB gene (D435Y, D435V, S450L, L452P). Isoniazid resistance mutations were found in the katG (S315T), inhA (C[-15] T), and ndh (R268H) genes, whereas ethambutol resistance mutations were observed in the embB gene (M306V, M306I, M306L, G406S, Q497R). Surprisingly, 94% of PZAr isolates (n = 31) showed no mutations in the pncA or rpsA genes. The presence of the R268H mutation in the ndh gene, not previously linked to PZAr, was detected in 15% of PZAr isolates (n = 5), suggesting its potential contribution to PZAr in specific cases but not as a predominant mechanism. The specific molecular mechanisms underlying PZAr in the majority of the isolates remain unknown, emphasizing the need for further research to uncover the contributing factors. These findings contribute to the understanding of drug resistance patterns and can guide future efforts in TB control and management.

High Prevalence of Plasminogen Activator Inhibitor-1 4G/5G Polymorphism among Patients with Venous Thromboembolism in Kerala, India.

Venous thromboembolism (VTE) is a multifactorial clotting disorder in which inherited and environmental factors synergistically contribute to its pathogenesis. The aim of this case-control study was to analyze the prevalence of hereditary thrombophilic risk factors, provoking and non-provoking environmental risk factors in patients with VTE from Kerala, India. We have observed a low prevalence of factor V Leiden (7%), prothrombin G20210A (2%), and prothrombin G20030A (2%) mutations and a high prevalence of plasminogen activator inhibitor-1 (PAI-1) 4G/5G (52%), PAI-1 4G/4G (24%) genotypes in the VTE patients (n = 147). Deficiency of anticoagulants, antithrombin (3.4%), and protein C (4.1%) was relatively low. None of the risk factors were observed in 17% of the patients. Majority of VTE patients were younger than 50 years with a median age of 43 years. In conclusion, our results indicate a high prevalence of PAI-1 4G/5G polymorphism among the VTE patients which is in concordance with previous studies in the Asian population. The PAI-1 4G/5G polymorphism could be a potential biomarker for assessing VTE risk, particularly among the Indian population.

Lipoproteins in Staphylococcus aureus mediate inflammation by TLR2 and iron-dependent growth in vivo.

Lipoproteins (Lpp) are ligands of TLR2 and signal by the adaptor MyD88. As part of the bacterial cell envelope, Lpp are mainly involved in nutrient acquisition for Staphylococcus aureus. The impact of Lpp on TLR2-MyD88 activation for S. aureus in systemic infection is unknown. S. aureus strain SA113 deficient in the enzyme encoded by the prolipoprotein diacylglyceryl transferase gene (Deltalgt), which attaches the lipid anchor to pro-Lpp, was used to study benefits and costs of Lpp maturation. Lpp in S. aureus induced early and strong cytokines by TLR2-MyD88 signaling in murine peritoneal macrophages. Lpp contributed via TLR2 to pathogenesis of sepsis in C57BL/6 mice with IL-1beta, chemokine-mediated inflammation, and high bacterial numbers. In the absence of MyD88-mediated inflammation, Lpp allowed bacterial clearing from liver devoid of infiltrating cells, but still conferred a strong growth advantage in mice, which was shown to rely on iron uptake and storage in vitro and in vivo. With iron-restricted bacteria, the Lpp-related growth advantage was evident in infection of MyD88(-/-), but not of C57BL/6, mice. On the other hand, iron overload of the host restored the growth deficit of Deltalgt in MyD88(-/-), but not in immunocompetent C57BL/6 mice. These results indicate that iron acquisition is improved by Lpp of S. aureus but is counteracted by inflammation. Thus, lipid anchoring is an evolutionary advantage for S. aureus to retain essential proteins for better survival in infection.

Molecular Mechanisms of Staphylococcus and Pseudomonas Interactions in Cystic Fibrosis.

Cystic fibrosis (CF) is an autosomal recessive genetic disorder that is characterized by recurrent and chronic infections of the lung predominantly by the opportunistic pathogens, Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa. While S. aureus is the main colonizing bacteria of the CF lungs during infancy and early childhood, its incidence declines thereafter and infections by P. aeruginosa become more prominent with increasing age. The competitive and cooperative interactions exhibited by these two pathogens influence their survival, antibiotic susceptibility, persistence and, consequently the disease progression. For instance, P. aeruginosa secretes small respiratory inhibitors like hydrogen cyanide, pyocyanin and quinoline N-oxides that block the electron transport pathway and suppress the growth of S. aureus. However, S. aureus survives this respiratory attack by adapting to respiration-defective small colony variant (SCV) phenotype. SCVs cause persistent and recurrent infections and are also resistant to antibiotics, especially aminoglycosides, antifolate antibiotics, and to host antimicrobial peptides such as LL-37, human ß-defensin (HBD) 2 and HBD3; and lactoferricin B. The interaction between P. aeruginosa and S. aureus is multifaceted. In mucoid P. aeruginosa strains, siderophores and rhamnolipids are downregulated thus enhancing the survival of S. aureus. Conversely, protein A from S. aureus inhibits P. aeruginosa biofilm formation while protecting both P. aeruginosa and S. aureus from phagocytosis by neutrophils. This review attempts to summarize the current understanding of the molecular mechanisms that drive the competitive and cooperative interactions between S. aureus and P. aeruginosa in the CF lungs that could influence the disease outcome.