Immunocompromised Individuals Research Articles

Bioinformatics Approaches in the Development of Antifungal Therapeutics and Vaccines

Abstract: Fungal infections are considered a great threat to human life and are associated with high mortality and morbidity, especially in immunocompromised individuals. Fungal pathogens employ various defense mechanisms to evade the host immune system, which causes severe infections. The available repertoire of drugs for the treatment of fungal infections includes azoles, allylamines, polyenes, echinocandins, and antimetabolites. However, the development of multidrug and pandrug resistance to available antimycotic drugs increases the need to develop better treatment approaches. In this new era of -omics, bioinformatics has expanded options for treating fungal infections. This review emphasizes how bioinformatics complements the emerging strategies, including advancements in drug delivery systems, combination therapies, drug repurposing, epitope- based vaccine design, RNA-based therapeutics, and the role of gut-microbiome interactions to combat anti-fungal resistance. In particular, we focused on computational methods that can be useful to obtain potent hits, and that too in a short period.

Role of ethanolamine utilization and bacterial microcompartment formation in Listeria monocytogenes intracellular infection.

Ethanolamine (EA) affects the colonization and pathogenicity of certain human bacterial pathogens in the gastrointestinal tract. However, EA can also affect the intracellular survival and replication of host cell invasive bacteria such as Listeria monocytogenes (LMO) and Salmonella enterica serovar Typhimurium (S. Typhimurium). The EA utilization (eut) genes can be categorized as regulatory, enzymatic, or structural, and previous work in LMO showed that loss of genes encoding functions for the enzymatic breakdown of EA inhibited LMO intracellular replication. In this work, we sought to further characterize the role of EA utilization during LMO infection of host cells. Unlike what was previously observed for S. Typhimurium, in LMO, an EA regulator mutant (ΔeutV) was equally deficient in intracellular replication compared to an EA metabolism mutant (ΔeutB), and this was consistent across Caco-2, RAW 264.7, and THP-1 cell lines. The structural genes encode proteins that self-assemble into bacterial microcompartments (BMCs) that encase the enzymes necessary for EA metabolism. For the first time, native EUT BMCs were fluorescently tagged, and EUT BMC formation was observed in vitro and in vivo. Interestingly, BMC formation was observed in bacteria infecting Caco-2 cells, but not the macrophage cell lines. Finally, the cellular immune response of Caco-2 cells to infection with eut mutants was examined, and it was discovered that ΔeutB and ΔeutV mutants similarly elevated the expression of inflammatory cytokines. In conclusion, EA sensing and utilization during LMO intracellular infection are important for optimal LMO replication and immune evasion but are not always concomitant with BMC formation.IMPORTANCEListeria monocytogenes (LMO) is a bacterial pathogen that can cause severe disease in immunocompromised individuals when consumed in contaminated food. It can replicate inside of mammalian cells, escaping detection by the immune system. Therefore, understanding the features of this human pathogen that contribute to its infectiousness and intracellular lifestyle is important. In this work we demonstrate that genes encoding both regulators and enzymes of EA metabolism are important for optimal growth inside mammalian cells. Moreover, the formation of specialized compartments to enable EA metabolism were visualized by tagging with a fluorescent protein and found to form when LMO infects some mammalian cell types, but not others. Interestingly, the formation of the compartments was associated with features consistent with an early stage of the intracellular infection. By characterizing bacterial metabolic pathways that contribute to survival in host environments, we hope to positively impact knowledge and facilitate new treatment strategies.

Prevalence of Intestinal Parasites among Diabetes Mellitus Patients in Tertiary Care Hospital

Intestinal parasitosis constitutes a serious problem of public health, especially in developing countries. Even though the population of immunocompromised individuals is growing, this is a primary cause of illness and mortality. Numerous studies have demonstrated that immunosuppressive medications, such as those used after transplantation, as well as immune suppression as a primary immunodeficiency in HIV infection, increase the possibility of infection and persistent states of carriage. People whose immune systems were weakened, like in the case of chronic internal disorders or abnormal metabolism, were thought to be more susceptible to infection. A group of metabolic non-communicable diseases known as diabetes mellitus (DM) are characterized by hyperglycemia or elevated blood sugar, which can be brought on by either inadequate secretion of insulin, insulin-resistant cells, or both. Parasitic infections in immunocompromised people are becoming more well-known as major opportunistic microorganisms that cause clinical illnesses. The goal of this research is to see how common intestinal parasite infections are in people with diabetes. The research was carried out at the Chandulal Chandrakar Memorial Medical College, Bhilai, Durg district of Chhattisgarh, India. From March to August 2020, diabetic patients who visited hospitals were studied in this cross-sectional study. This study comprised 188 diabetic individuals with type I or type II diabetes who were taking anti-diabetic medication. With a little spoon and a sterile, dry, leak-proof plastic container with a tight-fitting cover that had the patient’s name and identification number on it, the feces samples were taken. The container was then quickly sent to the parasitology lab of the microbiology department for processing. Stool samples were examined under three headings: macroscopic examination, microscopic examination, and formal ether concentration procedure. A total of 188 DM patients was included with data on socio-demographic characteristics, and from each patient stool sample were collected and processed. Out of which, 27 stool samples were positive for intestinal parasites; showed a prevalence of 14.36%. Female 16 (16.49%) revealed a greater frequency than that of men 11 (12.09%). The age range of 51 to 60 years old exhibited the highest incidence 8 (29.63 %). Stool samples were positive for intestinal parasites with one suffering from a dual infection. Various parasites were detected in which Entamoeba histolytica 10 (5.32%) was most common parasite to isolate followed by Ascaris lumbricoides 9 (4.79%) and Giardia lamblia 6 (3.19%) was least isolated parasite. The most prevalent isolated parasite was Entamoeba histolytica, which was followed by Cryptosporidium parvum. Diabetic patients have an increased risk of parasitic infections, particularly when they have the opportunistic infection Entamoeba histolytica. Patients with diabetes who have been diagnosed with Cryptosporidium parvum have a weaker immune system. Therefore, for the sake of societal welfare, people with diabetes mellitus should have routine stool examination screening for parasite infection.

Implementation of AZD7442 (Tixagevimab/Cilgavimab) COVID-19 Pre-exposure Prophylaxis (PrEP) in the Largest Health Maintenance Organization in Israel: Real-world Uptake and Sociodemographic and Clinical Characteristics Across Immunocompromised Patient Groups.

AZD7442 is a combination of two neutralizing antibodies (tixagevimab/cilgavimab) with demonstrated efficacy in reducing the risk of symptomatic coronavirus disease 2019 (COVID-19) among individuals at high risk of severe COVID-19 ≤ 6months after administration. On February 15, 2022, the Israeli Ministry of Health (IMoH) authorized the administration of 300mg AZD7442 as pre-exposure prophylaxis (PrEP) against severe acute respiratory syndrome coronavirus 2infection among immunocompromised individuals aged ≥ 12years. This study describes the real-world uptake of AZD7442 in Israel. This descriptive, observational study analyzed data from Israel's largest health maintenance organization, Clalit Health Services (CHS). Individuals were assessed for AZD7442 eligibility between February 13 and December 11, 2022, and were included if they were aged ≥ 12years, had ≥ 1year of continuous CHS membership, had≥ 1 moderate or severe immunocompromising condition, and were eligible for AZD7442 per IMoH recommendations during this time frame. Overall, 19,161 AZD7442-eligible individuals with immunocompromising conditions were identified during the study period; 2829 (14.8%) received AZD7442. A higher proportion of individuals receiving AZD7442 were older (aged ≥ 65years), male, not current smokers and residents in large cities; required more physician visits (> 50 visits); and had ≥ 1 COVID-19 hospitalization over 12months, while uptake was lowest among ultra-orthodox Jewish individuals. AZD7442 uptake was also higher among individuals with multiple comorbidities (Charlson Comorbidity Index ≥ 5), including hypertension, diabetes and chronic kidney disease. In specific immunocompromised types, AZD7442 uptake was highest among individuals with lung transplantation (41%), primary immunodeficiency (32%), bone marrow transplantation (29%) and multiple myeloma (25%) or those receiving anti-CD20 therapy (26%) and was lowest in individuals with lymphoma (8%). These results show AZD7442 uptake among the eligible population of Israel in 2022 was relatively low, at 14.8%. Uptake was generally higher among immunocompromised individuals who may be perceived to be frail or at highest risk of COVID-19 infection and complications, although at 25-41%, further improvements in uptake would be more impactful. These results also indicate there is opportunity to expand AZD7442 uptake across immunocompromised groups and ensure more equitable uptake among some other sociodemographic groups. Overall, this study will help inform and reassess future implementation strategies for vulnerable populations.

Epstein-Barr Virus-Associated Smooth-Muscle Tumor of the Brain.

Epstein-Barr virus, a herpesvirus, has been associated with a variety of cancers, including Burkitt, Hodgkin, and non-Hodgkin lymphomas; posttransplant lymphoproliferative disorders; gastric carcinoma; and nasopharyngeal carcinoma, in both immunocompetent and immunocompromised individuals. Previous studies have established a connection between Epstein-Barr virus and the development of smooth-muscle tumors. Smooth-muscle tumors of the brain are very rare and are often misdiagnosed as meningiomas on imaging. To our knowledge, advanced imaging findings such as MR perfusion of smooth-muscle tumors of the brain have never been reported. We describe the radiologic and pathologic features of the Epstein-Barr virus-associated smooth-muscle tumors of the brain in a person with newly diagnosed advanced HIV.

Assessment of the Seroprevalence of Varicella zoster Virus in Young Adults Aged 15 – 35 Years Old in Mashhad, Iran

Background: Varicella zoster virus (VZV) is highly contagious and can lead to two distinct diseases. Initially, it causes chickenpox, a primary infection common among children worldwide, characterized by itchy, red blisters that cover the body. After this initial outbreak, the virus can lie dormant in nerve tissues and may reactivate later in life as herpes zoster, commonly known as shingles, which presents as a painful rash. While chickenpox is generally mild and resolves on its own, it can cause severe complications, especially in vulnerable groups such as immunocompromised individuals or adults. These complications can range from bacterial superinfections and pneumonia to encephalitis. In rare cases, it may lead to life-threatening conditions like necrotizing fasciitis or toxic shock syndrome, highlighting the potential severity of what is often considered a childhood illness. Objectives: One of the main risk factors for varicella-zoster infection is the absence of immunity. Individuals who have not been vaccinated against or previously infected with the VZV are at risk of contracting chickenpox when exposed. Additionally, close contact with infected individuals increases the likelihood of transmission. People with chronic conditions or those undergoing immunosuppressive therapy are particularly vulnerable to severe complications from varicella-zoster infections. Therefore, this study was conducted to assess the seroepidemiology of antibodies against varicella zoster in the young adult population in Mashhad. Methods: This cross-sectional study was conducted in 2018 on men and women aged 15 to 35 years in Mashhad, northeast Iran. Random cluster sampling was utilized. Individuals undergoing treatment for rare diseases were excluded from the study. The enzyme-linked immunoassay (ELISA) technique was employed to assess the presence of IgG antibodies against varicella zoster in 724 serum samples. Data analysis was performed using SPSS 20, and the significance level was set at 0.05. Results: Overall, among the 724 participants aged 15 - 35 years old in Mashhad, the frequency of anti-varicella IgG seropositivity was 85.9%. Our results indicated significant associations between age (P = 0.001) and occupational status (P = 0.02) with varicella-zoster seroprevalence. Conclusions: We observed a high frequency of anti-varicella zoster IgG seroprevalence among young adults in Mashhad. Infants, pregnant women, and individuals with weakened immune systems are more likely to develop severe forms of chickenpox or experience complications from shingles, including pneumonia and encephalitis. Given the severe health problems caused by the varicella virus and its high prevalence in Mashhad, we recommend incorporating the varicella vaccine into the public vaccination program. Additionally, further examination of the burden of herpes zoster, including its impact on quality of life and healthcare utilization, can guide interventions to mitigate the consequences of this condition.

RSV infection of humanized lung-only mice induces pathological changes resembling severe bronchiolitis and bronchopneumonia

Respiratory syncytial virus (RSV) is a substantial cause of severe lower respiratory tract infections in infants, young children, older adults, and immunocompromised individuals. There is a vital need for effective therapeutics to prevent and/or treat severe RSV infection in these high-risk individuals. The development and pre-clinical testing of candidate RSV therapeutics could be accelerated by their evaluation in animal models that recapitulate bronchiolitis and bronchopneumonia, both hallmark features of severe RSV infection in humans. Previously, we demonstrated that implanted human lung tissue in humanized lung-only mice (LoM) can be infected with RSV, resulting in sustained virus replication. Here we analyzed RSV-associated human lung pathology in the human lung implants of RSV-infected LoM. RSV-infected epithelial cells lining the airway and the alveolar regions of human lung implants result in hallmark histological features of RSV bronchiolitis and bronchopneumonia, including distal airway and alveolar lumens clogged with (1) sloughed and necrotic RSV-infected epithelial cells, (2) neutrophil-containing inflammatory infiltrates, and (3) MUC5B-dominated mucus secretions. We also show that treatment of LoM with a small molecule antiviral (ribavirin) or a neutralizing antibody (palivizumab) significantly suppressed and/or prevented RSV infection in vivo. Our data together show that RSV infection of human lung implants in vivo exhibits appropriate cellular tropism and results in the hallmark pathological characteristics of severe bronchiolitis and bronchopneumonia in humans. They also offer proof-of-principle of the utility of this model to evaluate novel approaches for the prevention/treatment of RSV infection.

An oxylipin signal confers protection against antifungal echinocandins in pathogenic aspergilli

Aspergillus fumigatus is the leading causative agent of life-threatening invasive aspergillosis in immunocompromised individuals. One antifungal class used to treat Aspergillus infections is the fungistatic echinocandins, semisynthetic drugs derived from naturally occurring fungal lipopeptides. By inhibiting beta-1,3-glucan synthesis, echinocandins cause both fungistatic stunting of hyphal growth and repeated fungicidal lysis of apical tip compartments. Here, we uncover an endogenous mechanism of echinocandin tolerance in A. fumigatus whereby the inducible oxylipin signal 5,8-diHODE confers protection against tip lysis via the transcription factor ZfpA. Treatment of A. fumigatus with echinocandins induces 5,8-diHODE synthesis by the fungal oxygenase PpoA in a ZfpA dependent manner resulting in a positive feedback loop. This protective 5,8-diHODE/ZfpA signaling relay is conserved among diverse isolates of A. fumigatus and in two other Aspergillus pathogens. Our findings reveal an oxylipin-directed growth program—possibly arisen through natural encounters with native echinocandin producing fungi—that enables echinocandin tolerance in pathogenic aspergilli.

Epidemiological Aspects and Basic Directions of the Protective Medications against Monkeypox Development

Relevance. After smallpox eradication, in conditions of population immunity to orthopoxviruses absence, Monkeypox virus became most significant orthopoxvirus, pathogenic for humans. Therefore the generalization of data on the areas of infection outbreaks, human diseases and methods of prevention and treatment of monkey pox is important task. Aim. To characterize the problem of monkeypox in the world based on an analysis of foreign scientific publications over the past 20 years. Materials and methods. The work used publications presented in the main international medical information databases PubMed, Web of Science, Embase, etc. To analyze the publications, the analytical epidemiological method was used. Results and discussion. Monkeypox virus, obtained and identified in 1958, by genetic and phenotypic differences divides on two clades: West-African with lethality 3.6% and Central-African (Congo Basin) with lethality 10%. Monkeypox virus transmission to men happens in two ways, either from animal-to-human or human-to-human. Monkey pox is endemic only on African continent, but In 2003 year the first outbreak, numbering 47 confirmed cases, was occurred in non-endemic country – USA and the largest monkeypox outbreak began in Nigeria in September 2017 year and continue to the present. Comparison of the genome sequences of strains, isolated from patients in non-endemic countries, showed, that it genetically close to West-african strains, belong to II clades and were descended from a common ancestor. Many cases of disease in humans in the current outbreak have been traced to sexual transmission especially among men, who identify ourselves as gay or bisexual. The basis method for identification of agent in present time is PCR-RT targeting on the tumor necrosis factor (TNF) receptor gene. Usually monkeypox of human is mild, self-limiting disease. The symptoms of monkeypox are varied and non-specific. One of the most frequently observed clinical symptoms is lymphadenopathy. Most patients recover during some weeks. However, specific antiviral treatment – tecovirimat (S-246) and brincidofovir (CMX-001) – may be used for seriously ill or immunocompromised individuals. For prophylactic disease in present time are use vaccines JYNNEOSTM, ACAM2000R and Aventis Pasteur (APSV). Conclusion. General vaccination against monkeypox don't develop accordingly to modern recommendations WHO. Ring vaccination is recommended to conduct for suppression of spread virus in nidus of infection among population. Timely international coordination is needed to prevent the global spread of a disease with epidemic potential.

Prevalence of Diagnosed Genital Herpes and Antiviral Treatment in the United States.

Genital herpes is a common sexually transmitted infection caused by the herpes simplex virus. Contemporary United States (US) population-based epidemiologic data on genital herpes are limited. This study aimed to provide nationally representative estimates of genital herpes prevalence and treatment using a large US health insurance claims database. This observational cohort study used administrative claims data from HealthVerity. Crude and age- and sex-standardized prevalence rates of genital herpes and recurrent genital herpes were calculated for the years 2019 to 2021. The distribution of patients with prevalent genital herpes who received episodic or suppressive antiviral therapy was also estimated. From 2019 to 2021, the standardized prevalence of genital herpes and recurrent genital herpes ranged from 236 to 280 cases per 100,000 person-years and 81 to 98 cases per 100,000 person-years, respectively. The prevalence of genital herpes was highest among those aged 25-29 years (prevalence range: 497 to 582), female patients (prevalence range: 348 to 404), and those with a history of HIV infection (prevalence range: 1608 to 2080). The prevalence of recurrent genital herpes was also highest in these groups. From 2019 to 2021, two-thirds of patients (65% to 68%) with prevalent genital herpes received antiviral medications; the majority received episodic therapy (80%) rather than suppressive therapy (20%). The burden of genital herpes and recurrent genital herpes in the US is substantial, with the highest rates observed in young adults, women, and immunocompromised individuals. About two-thirds receive antiviral treatment each year.

A cholangiocyte organoid system for Cryptosporidium parvum cultivation and transcriptomic studies of biliary cryptosporidiosis

Biliary cryptosporidiosis caused by Cryptosporidium is life-threatening in immunocompromised individuals, particularly those with acquired immune deficiency syndrome (AIDS), resulting in AIDS cholangiopathy. However, studies of biliary cryptosporidiosis have lagged due to the lack of in vitro models that allow complete pathogen development. Here we describe procedures for the generation of mouse cholangiocyte organoids (Chol-orgs). The Chol-orgs, which expressed stem and biliary cell markers, could be clonally expanded for three months and stored in liquid nitrogen for more than one year. Combined with cell differentiation using the air-liquid interface (ALI) approach, we established a culture system for Cryptosporidium parvum. ALI cultures using Chol-orgs have supported ∼50-fold amplification of the pathogen and generated viable oocysts in vitro. In addition, we analyzed the transcriptome of Chol-ALI cultures infected with the IId subtype of C. parvum to characterize host cell responses. RNA-seq analysis revealed that C. parvum upregulated immune and inflammatory responses and downregulated metabolic and cell proliferation signaling pathways in Chol-orgs. A similar system using bovine cholangiocytes also supported the complete development of C. parvum in vitro. These in vitro models provide convenient methods to study biliary cryptosporidiosis and other hepatic infections and to develop effective therapies for AIDS cholangiopathy.

Immunogenicity of third dose COVID-19 vaccine strategies in patients who are immunocompromised with suboptimal immunity following two doses (OCTAVE-DUO): an open-label, multicentre, randomised, controlled, phase 3 trial

The humoral and T-cell responses to booster COVID-19 vaccine types in multidisease immunocompromised individuals who do not generate adequate antibody responses to two COVID-19 vaccine doses, is not fully understood. The OCTAVE DUO trial aimed to determine the value of third vaccinations in a wide range of patients with primary and secondary immunodeficiencies. OCTAVE-DUO was a prospective, open-label, multicentre, randomised, controlled, phase 3 trial investigating humoral and T-cell responses in patients who are immunocompromised following a third vaccine dose with BNT162b2 or mRNA-1273, and of NVX-CoV2373 for those with lymphoid malignancies. We recruited patients who were immunocompromised from 11 UK hospitals, aged at least 18 years, with previous sub-optimal responses to two doses of SARS-CoV-2 vaccine. Participants were randomly assigned 1:1 (1:1:1 for those with lymphoid malignancies), stratified by disease, previous vaccination type, and anti-spike antibody response following two doses. Individuals with lived experience of immune susceptibility were involved in the study design and implementation. The primary outcome was vaccine-specific immunity defined by anti-SARS-CoV-2 spike antibodies (Roche Diagnostics UK and Ireland, Burgess Hill, UK) and T-cell responses (Oxford Immunotec, Abingdon, UK) before and 21 days after the third vaccine dose analysed by a modified intention-to-treat analysis. The trial is registered with the ISRCTN registry, ISRCTN 15354495, and the EU Clinical Trials Register, EudraCT 2021-003632-87, and is complete. Between Aug 4, 2021 and Mar 31, 2022, 804 participants across nine disease cohorts were randomly assigned to receive BNT162b2 (n=377), mRNA-1273 (n=374), or NVX-CoV2373 (n=53). 356 (45%) of 789 participants were women, 433 (55%) were men, and 659 (85%) of 775 were White. Anti-SARS-CoV-2 spike antibodies measured 21 days after the third vaccine dose were significantly higher than baseline pre-third dose titres in the modified intention-to-treat analysis (median 1384 arbitrary units [AU]/mL [IQR 4·3-7990·0] compared with median 11·5 AU/mL [0·4-63·1]; p<0·001). Of participants who were baseline low responders, 380 (90%) of 423 increased their antibody concentrations to more than 400 AU/mL. Conversely, 166 (54%) of 308 baseline non-responders had no response after the third dose. Detectable T-cell responses following the third vaccine dose were seen in 494 (80%) of 616 participants. There were 24 serious adverse events (BNT612b2 eight [33%] of 24, mRNA-1273 12 [50%], NVX-CoV2373 four [17%]), two (8%) of which were categorised as vaccine-related. There were seven deaths (1%) during the trial, none of which were vaccine-related. A third vaccine dose improved the serological and T-cell response in the majority of patients who are immunocompromised. Individuals with chronic renal disease, lymphoid malignancy, on B-cell targeted therapies, or with no serological response after two vaccine doses are at higher risk of poor response to a third vaccine dose. Medical Research Council, Blood Cancer UK.

Malakoplakia: A rare cause of hematochezia in pediatric patients

AbstractMalakoplakia is a rare inflammatory condition characterized by impaired macrophages unable to completely digest and kill phagocytized bacteria, resulting in partially digested bacterial components accumulating within the phagolysosome. Malakoplakia typically presents in immunocompromised individuals due to underlying disease or to medication effects and is rarely diagnosed in the pediatric population. The urinary tract is the most commonly involved site, followed by the gastrointestinal (GI) tract, mainly affecting the descending colon, sigmoid colon, and rectum. Treatment focuses on the use of antibiotics that concentrate in macrophages such as quinolones and trimethoprim‐sulfamethoxazole as well as cholinergic agents such as bethanechol, which raise intracellular levels of cyclic guanosine monophosphate in macrophages to improve bactericidal activity. We report a rare case of GI tract malakoplakia in a pediatric patient undergoing treatment for leukemia.

Emergence of colistin-resistant Stenotrophomonas maltophilia with high virulence in natural aquatic environments

The presence of Stenotrophomonas maltophilia in aquatic environments poses great health risks to immunocompromised individuals because of its multidrug resistance and resultant high mortality. However, a significant gap exists in the isolation and understanding of colistin-resistant S. maltophilia in aquatic environments. In this study, nine colistin-resistant S. maltophilia strains isolated from natural lakes were explored, and their phylogenetic relationship, biofilm formation, virulence, and antibiotic resistance profiles and underlying genetic determinants were assessed. After genome analysis, besides known multi-locus sequence typing (MLST) of ST532, new assigned ST965 and ST966 which phylogenetically clustered into soil isolates were found firstly. All the isolates exhibited resistance to multiple antibiotics, including aminoglycosides, beta-lactams, tetracyclines, and even colistin, with the highest minimum inhibitory concentration (MIC) against colistin reaching 640 mg/L. Comparative genomic analysis revealed aph(3′)-Iic, blaL1, tetT, phoP, mcr-3, arnA, pmrE, and efflux pump genes as the genetic determinants underlying this multidrug resistance. Notably, the biofilm-forming capacities of the newly discovered ST965 and ST966 isolates were significant stronger than those of the known ST532 isolates (p < 0.01), resulting in the death of over 50 % of the Galleria mellonella population within 1 day of injection. The ST965 isolates demonstrated the highest virulence against G. mellonella, followed by the ST966 isolates and ST532 isolates which was phylogenetically clustered with clinical isolates, indicating that the novel S. maltophilia strains of ST965 and ST966 may pose considerable health risks to humans. Our findings provide insights into colistin-resistant S. maltophilia in aquatic environments and raise concerns about the health risks posed by the newly assigned sequence types of colistin-resistant S. maltophilia with potential high virulence in natural aquatic environments.

Comprehensive Review on the Virulence Factors and Therapeutic Strategies with the Aid of Artificial Intelligence against Mucormycosis.

Mucormycosis, a rare but deadly fungal infection, was an epidemic during the COVID-19 pandemic. The rise in cases (COVID-19-associated mucormycosis, CAM) is attributed to excessive steroid and antibiotic use, poor hospital hygiene, and crowded settings. Major contributing factors include diabetes and weakened immune systems. The main manifesting forms of CAM─cutaneous, pulmonary, and the deadliest, rhinocerebral─and disseminated infections elevated mortality rates to 85%. Recent focus lies on small-molecule inhibitors due to their advantages over standard treatments like surgery and liposomal amphotericin B (which carry several long-term adverse effects), offering potential central nervous system penetration, diverse targets, and simpler dosing owing to their small size, rendering the ability to traverse the blood-brain barrier via passive diffusion facilitated by the phospholipid membrane. Adaptation and versatility in mucormycosis are facilitated by a multitude of virulence factors, enabling the pathogen to dynamically respond to various environmental stressors. A comprehensive understanding of these virulence mechanisms is imperative for devising effective therapeutic interventions against this highly opportunistic pathogen that thrives in immunocompromised individuals through its angio-invasive nature. Hence, this Review delineates the principal virulence factors of mucormycosis, the mechanisms it employs to persist in challenging host environments, and the current progress in developing small-molecule inhibitors against them.

Deep mutational scanning of Pneumocystis jirovecii dihydrofolate reductase reveals allosteric mechanism of resistance to an antifolate.

Pneumocystis jirovecii is a fungal pathogen that causes pneumocystis pneumonia, a disease that mainly affects immunocompromised individuals. This fungus has historically been hard to study because of our inability to grow it in vitro. One of the main drug targets in P. jirovecii is its dihydrofolate reductase (PjDHFR). Here, by using functional complementation of the baker's yeast ortholog, we show that PjDHFR can be inhibited by the antifolate methotrexate in a dose-dependent manner. Using deep mutational scanning of PjDHFR, we identify mutations conferring resistance to methotrexate. Thirty-one sites spanning the protein have at least one mutation that leads to resistance, for a total of 355 high-confidence resistance mutations. Most resistance-inducing mutations are found inside the active site, and many are structurally equivalent to mutations known to lead to resistance to different antifolates in other organisms. Some sites show specific resistance mutations, where only a single substitution confers resistance, whereas others are more permissive, as several substitutions at these sites confer resistance. Surprisingly, one of the permissive sites (F199) is without direct contact to either ligand or cofactor, suggesting that it acts through an allosteric mechanism. Modeling changes in binding energy between F199 mutants and drug shows that most mutations destabilize interactions between the protein and the drug. This evidence points towards a more important role of this position in resistance than previously estimated and highlights potential unknown allosteric mechanisms of resistance to antifolate in DHFRs. Our results offer unprecedented resources for the interpretation of mutation effects in the main drug target of an uncultivable fungal pathogen.

Safety and effectiveness of single- versus double-dose of seasonal influenza vaccine in kidney transplant recipients: a randomized clinical trial

Introduction. Influenza virus poses significant risks to immunocompromised individuals such as those who have received organ transplants and are undergoing immunosuppressive treatment to prevent transplant rejection. Therefore, annual influenza vaccination is recommended for these individuals. This study aimed to comparison of safety and effectiveness of single- versus double-dose of seasonal influenza vaccine in kidney transplant recipients. Materials and methods. This randomized clinical trial involved 50 kidney transplant recipients at Imam Khomeini Hospital. Participants were randomly assigned to two groups: those receiving a single dose (standard dose) and those receiving a double dose of the seasonal flu vaccine. Serum samples were collected before and 4 weeks after vaccination to measure influenza AB-related antibodies. Sixteen patients were excluded from the study. The trial focused on evaluating the vaccine safety and immunogenicity, as well as documenting any local and systemic side effects following vaccination. Results. The results indicated no significant difference in gender, age, and type of immunosuppressive drug used between the single- and double-dose groups (p 0.05). No significant difference in post-vaccination adverse effects, such as injection site pain (p = 0.21) between the two groups. The seroconversion rates (change from IgG 9 IU/µL to IgG 11 IU/µL) for IgG Influenza A were 12.5% (n = 2) in the single-dose group and 26.7% (n = 4) in the double-dose group, and for IgG Influenza B, they were 11.8% (n = 2) and 21.4% (n = 3), respectively. Conclusion. A double dose of the influenza vaccine slightly enhanced the immune response in kidney transplant patients without causing any adverse side effects.

AAV-vectored expression of monospecific or bispecific monoclonal antibodies protects mice from lethal Pseudomonas aeruginosa pneumonia.

Pseudomonas aeruginosa poses a significant threat to immunocompromised individuals and those with cystic fibrosis. Treatment relies on antibiotics, but persistent infections occur due to intrinsic and acquired resistance of P. aeruginosa towards multiple classes of antibiotics. To date, there are no licensed vaccines for this pathogen, prompting the urgent need for novel treatment approaches to combat P. aeruginosa infection and persistence. Here we validated AAV vectored immunoprophylaxis as a strategy to generate long-term plasma and mucosal expression of highly protective monoclonal antibodies (mAbs) targeting the exopolysaccharide Psl (Cam-003) and the PcrV (V2L2MD) component of the type-III secretion system injectosome either as single mAbs or together as a bispecific mAb (MEDI3902) in a mouse model. When administered intramuscularly, AAV-αPcrV, AAV-αPsl, and AAV-MEDI3902 significantly protected mice challenged intranasally with a lethal dose of P. aeruginosa strains PAO1 and PA14 and reduced bacterial burden and dissemination to other organs. While all AAV-mAbs provided protection, AAV-αPcrV and AAV-MEDI3902 provided 100% and 87.5% protection from a lethal challenge with 4.47 × 107 CFU PAO1 and 87.5% and 75% protection from a lethal challenge with 3 × 107 CFU PA14, respectively. Serum concentrations of MEDI3902 were ~10× lower than that of αPcrV, but mice treated with this vector showed a greater reduction in bacterial dissemination to the liver, lung, spleen, and blood compared to other AAV-mAbs. These results support further investigation into the use of AAV vectored immunoprophylaxis to prevent and treat P. aeruginosa infections and other bacterial pathogens of public health concern for which current treatment strategies are limited.

Identification of Protein Biomarkers for Differentiating Listeria monocytogenes Genetic Lineage III.

Listeria monocytogenes is the causative agent of listeriosis, a severe foodborne illness characterized by septicemia, meningitis, encephalitis, abortions, and occasional death in infants and immunocompromised individuals. L. monocytogenes is composed of four genetic lineages (I, II, III, and IV) and fourteen serotypes. The aim of the current study was to identify proteins that can serve as biomarkers for detection of genetic lineage III strains based on simple antibody-based methods. Liquid chromatography (LC) with electrospray ionization tandem mass spectrometry (ESI MS/MS) followed by bioinformatics and computational analysis were performed on three L. monocytogenes strains (NRRL B-33007, NRRL B-33014, and NRRL B-33077), which were used as reference strains for lineages I, II, and III, respectively. Results from ESI MS/MS revealed 42 unique proteins present in NRRL B-33077 and absent in NRRL B-33007 and NRRL B-33014 strains. BLAST analysis of the 42 proteins against a broader panel of >80 sequenced strains from lineages I and II revealed four proteins [TM2 domain-containing protein (NRRL B-33077_2770), DUF3916 domain-containing protein (NRRL B-33077_1897), DNA adenine methylase (NRRL B-33077_1926), and protein RhsA (NRRL B-33077_1129)] that have no homology with any sequenced strains in lineages I and II. The four genes that encode these proteins were expressed in Escherichia coli strain DE3 and purified. Polyclonal antibodies were prepared against purified recombinant proteins. ELISA using the polyclonal antibodies against 12 L. monocytogenes lineage I, II, and III isolates indicated that TM2 protein and DNA adenine methylase (Dam) detected all lineage III strains with no reaction to lineage I and II strains. In conclusion, two proteins including TM2 protein and Dam are potentially useful biomarkers for detection and differentiation of L. monocytogenes lineage III strains in clinical, environmental, and food processing facilities. Furthermore, these results validate the approach of using a combination of proteomics and bioinformatics to identify useful protein biomarkers.

Innovative therapies for treatment of invasive fungal diseases

Invasive fungal diseases (IFD) are difficult to treat and pose a significant threat to immunocompromised individuals. Current antifungal agents face limitations, including antifungal resistance and adverse effects. This review aims to give a comprehensive overview of emerging treatment strategies.Novel drugs in development are Ibrexafungerp, an orally available triterpenoid inhibiting glucan synthesis, and Rezafungin representing the echinocandins with extended half-life and improved tissue penetration, both recently licensed for certain indications. Fosmanogepix targets glycosylphosphatidylinositol biosynthesis, while Olorofim, an orotomide, inhibits fungal nucleic acid synthesis, both currently assessed in advanced clinical trials.Immunotherapeutic approaches include immune checkpoint inhibitors to enhance immune response in immunosuppressed individuals and fungal-specific allogeneic CAR-T cell therapy. For prophylactic purpose in high-risk populations to develop IFD, monoclonal antibodies against different virulence factors of Candida spp. have been discovered but are not yet seen in clinical trials. Vaccines against distinct fungal antigens as well as pan fungal vaccines to prevent IFD are under development in preclinical stages, notably for Candida spp., Cryptococcus spp., and Aspergillus spp., however, their clinical value is still discussed.In summary, major advances to treat IFD have been observed, but challenges for their establishment in the clinical routine persist.