Necroptosis: a regulated inflammatory mode of cell death

Programmed cell death has a vital role in embryonic development and tissue homeostasis. Necroptosis is an alternative mode of regulated cell death mimicking features of apoptosis and necrosis. Necroptosis requires protein RIPK3 (previously well recognized as regulator of inflammation, cell survival, and disease) and its substrate MLKL, the crucial players of this pathway. Necroptosis is induced by toll-like receptor, death receptor, interferon, and some other mediators. Shreds of evidence based on a mouse model reveals that deregulation of necroptosis has been found to be associated with pathological conditions like cancer, neurodegenerative diseases, and inflammatory diseases. In this timeline article, we are discussing the molecular mechanisms of necroptosis and its relevance to diseases.

Effective Antimicrobial Activity of Green ZnO Nano Particles of Catharanthus roseus

In the present study, zinc oxide nanoparticles (ZnO NPs) were synthesized using leaf extract of Catharanthus roseus (C. roseus) under different physical parameters. Biosynthesis of ZnO NPs was confirmed by UV-Visible spectrophotometer and further, characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray spectroscopy (EDX), Atomic Force Microscopy (AFM), Photoluminescence study and Dynamic Light Scattering (DLS). We have also confirmed that several physical parameters such as pH, temperature, concentration of metal ions and reaction time were able to regulate shape and size of synthesized ZnO NPs. XRD and TEM analysis provided the information about the average size and hexagonal morphology of ZnO NPs. FTIR spectra analysis suggested that phenolic compounds played crucial role in the biosynthesis of ZnO NPs. The significant antibacterial activity of ZnO NPs was observed against Staphylococcus aureus MTCC 9760 (S. aureus), Streptococcus pyogenes MTCC 1926 (S. pyogenes), Bacillus cereus MTCC 430 (B. cereus), Pseudomonas aeruginosa MTCC 424 (P. aeruginosa), Proteus mirabilis MTCC 3310 (P. mirabilis) and Escherichia coli MTCC 40 (E. coli). The synthesized ZnO NPs have shown antibacterial efficacy against both Gram-positive and Gram-negative pathogens. Synergistic effects of ZnO NPs and streptomycin showed increased efficacy as indicated by the increased zone of clearance in comparison to their individual effects (either ZnO NPs or streptomycin). Overall, the results elucidated a rapid, cost-effective, environmentally friendly and convenient method for ZnO NPs synthesis, which could be used as a potential antimicrobial agent against drug resistant microbes.

Role of Bacterioferritin & Ferritin in M. tuberculosis Pathogenesis and Drug Resistance: A Future Perspective by Interactomic Approach

Tuberculosis is caused by Mycobacterium tuberculosis, one of the most successful and deadliest human pathogen. Aminoglycosides resistance leads to emergence of extremely drug resistant strains of M. tuberculosis. Iron is crucial for the biological functions of the cells. Iron assimilation, storage and their utilization is not only involved in pathogenesis but also in emergence of drug resistance strains. We previously reported that iron storing proteins (bacterioferritin and ferritin) were found to be overexpressed in aminoglycosides resistant isolates. In this study we performed the STRING analysis of bacterioferritin & ferritin proteins and predicted their interactive partners [ferrochelatase (hemH), Rv1877 (hypothetical protein/probable conserved integral membrane protein), uroporphyrinogen decarboxylase (hemE) trigger factor (tig), transcriptional regulatory protein (MT3948), hypothetical protein (MT1928), glnA3 (glutamine synthetase), molecular chaperone GroEL (groEL1 & hsp65), and hypothetical protein (MT3947)]. We suggested that interactive partners of bacterioferritin and ferritin are directly or indirectly involved in M. tuberculosis growth, homeostasis, iron assimilation, virulence, resistance, and stresses.

Colistin Resistance and Management of Drug Resistant Infections

Colistin resistance is a globalized sensible issue because it has been considered a drug of the last-line resort to treat drug-resistant bacterial infections. The product of the mobilized colistin resistance (mcr) gene and its variants are the significant causes of colistin resistance, which is emerging due to the frequent colistin use in veterinary, and these genes circulate among the bacterial community. Apart from mcr genes, some other intrinsic genes and proteins are also involved in colistin resistance. Researchers focus on the most advanced genomics (whole genome sequencing), proteomics, and bioinformatics approaches to explore the question of colistin resistance. To combat colistin resistance, researchers developed various strategies such as the development of newer drugs, the repurposing of existing drugs, combinatorial treatment by colistin with other drugs, a nano-based approach, photodynamic therapy, a CRISPRi-based strategy, and a phage-based strategy. In this timeline review, we have discussed the development of colistin resistance and its management in developing countries.

Repurposing and Revival of the Drugs: A New Approach to Combat the Drug Resistant Tuberculosis

Emergence of drug resistant tuberculosis like multi drug resistant tuberculosis (MDR-TB), extensively drug-resistant tuberculosis (XDR-TB) and totally drug resistant tuberculosis (TDR-TB) has created a new challenge to fight against these bad bugs of Mycobacterium tuberculosis. Repurposing and revival of the drugs are the new trends/options to combat these worsen situations of tuberculosis in the antibiotics resistance era or in the situation of global emergency. Bactericidal and synergistic effect of repurposed/revived drugs along with the latest drugs bedaquiline and delamanid used in the treatment of MDR-TB, XDR-TB, and TDR-TB might be the choice for future promising combinatorial chemotherapy against these bad bugs.

M. tuberculosis Hypothetical Proteins and Proteins of Unknown Function: Hope for Exploring Novel Resistance Mechanisms as well as Future Target of Drug Resistance

Drug resistance in tuberculosis predominantly, mono-resistance, multi drug resistance, extensively drug resistance and totally drug resistance have emerged as a major problem in the chemotherapy of tuberculosis. Failures of first and second line anti-tuberculosis drugs treatment leads to emergence of resistant Mycobacterium tuberculosis. Few genes are reported as the principal targets of the resistance and apart from the primary targets many explanations have been proposed for drug resistance but still some resistance mechanisms are unknown. As proteins involved in most of the biological processes, these are potentially explored the unknown mechanism of drug resistance and attractive targets for diagnostics/future therapeutics against drug resistance. In last decade a panel of studies on expression proteomics of drug resistant M. tuberculosis isolates reported the differential expression of uncharacterized proteins and suggested these might be involved in resistance. Here we emphasize that detailed bioinformatics analysis (like molecular docking, pupylation, and proteins-proteins interaction) of these uncharacterized and hypothetical proteins might predict their interactive partners (other proteins) which are involved in various pathways of M. tuberculosis system biology and might give a clue for novel mechanism of drug resistance or future drug targets. In future these uncharacterized targets might be open the new resistance mechanism and used as potential drug targets against drug resistant tuberculosis.

Potential Alternative Strategy against Drug Resistant Tuberculosis: A Proteomics Prospect

Mycobacterium tuberculosis is one of the deadliest human pathogen of the tuberculosis diseases. Drug resistance leads to emergence of multidrug-resistant and extremely drug resistant strains of M. tuberculosis. Apart from principal targets of resistance, many explanations have been proposed for drug resistance but some resistance mechanisms are still unknown. Recently approved line probe assay (LPA) diagnostics for detecting the resistance to first and second line drugs are unable to diagnose the drug resistance in M. tuberculosis isolates which do not have the mutations in particular genes responsible for resistance. Proteomics and bioinformatic tools emerged as direct approaches for identification and characterization of novel proteins which are directly and indirectly involved in drug resistance that could be used as potential targets in future. In future, these novel targets might reveal new mechanism of resistance and can be used in diagnostics or as drug targets.

Environmental factors and their role in the transmission of SARS-CoV-2

In December of 2019, several cases of atypical pneumonia caused by an unknown agent were reported in Wuhan, the capital city of Hubei Province in China. In early January 2020, it was announced that these cases were caused by a novel coronavirus. The virus was later named Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which causes a disease associated with atypical pneumonia termed Corona virus disease 2019 (COVID-19). Several respiratory viruses, including coronaviruses and influenza viruses tend to have prominent peaks of infection during colder seasons, especially in temperate regions. The cold temperatures, along with accompanying dry conditions can drive respiratory tract infections by assisting with viral transmission, weakening the human immune system, and increasing viral molecular stability. Though the topic of SARS-CoV-2 transmission and warm weather has been associated with misinformation campaigns, it is worth investigating since an informative answer may give an indication of the future behavior of SARS-CoV-2.

Repurposing of the childhood vaccines: could we train the immune system against the SARS-CoV-2

INTRODUCTION

The COVID-19 pandemic is a globalized health concern caused by a beta-coronavirus named Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Since December 2019, when this outbreak flared in Wuhan, China, COVID-19 cases have been continuously rising all over the world. Due to the emergence of SARS-CoV-2 mutants, subsequent waves are flowing in a faster manner as compared to the primary wave, which is more contagious and causing higher mortality. Recently, India has emerged as the new epicenter of the second wave by mutants of SARS-CoV-2. After almost eighteen months of this outbreak, some COVID-19 dedicated therapeutics and vaccines are available, and a few are under trial, but the situation is still uncontrolled.

AREA COVERED

This perspective article covers the repurposing of childhood vaccines like Bacille Calmette-Guerin (BCG), Measles, Mumps, Rubella (MMR), and Oral Polio Vaccine (OPV), which are live attenuated vaccines and have been shown the protective effect through 'trained immunity and 'crossreactivity.'

EXPERT OPINION

This perspective article has suggested that combinatorial use of these childhood vaccines might exert a better protective effect along with the available COVID-19 therapeutic and vaccines which could be considered as a preventive option against SARS-CoV-2 infection as well as its subsequent waves.

Exploring the Mystery of Angiotensin-Converting Enzyme II (ACE2) in the Battle against SARS-CoV-2

COVID-19 is the newly born pandemic caused by the SARS-CoV-2 virus, which is the recently emerged betacoronavirus that crosses the species barrier. It predominantly infects pneumocytes of the respiratory tract, but due to the presence of angiotensin-converting enzyme II (ACE2) on other cells like surface enterocytes of the upper esophagus and colon, these are also considered as the primary sites of infection. ACE2 receptor served as a cellular entry point for SARS-CoV-2. The expression of the ACE2 receptors is regulated by several factors such as age, tobacco smoking, inflammatory signaling, ACE inhibitors, angiotensin receptor blockers, and comorbidities (chronic obstructive pulmonary disease (COPD), tuberculosis, cerebrovascular disease, coronary heart disease, hypertension, and diabetes). Therefore, scientists are trying to explore the in-depth knowledge of ACE2 and considered it as a potential indirect target for COVID-19 therapeutics. In this focused review, we discussed in detail ACE2 expressions and regulation by different factors in the primary or vulnerable sites of SARS-CoV-2 infections. Clinical trials of rhACE2 in COVID-19 patients are ongoing, and if the outcome of the trials proves positive, it will be a breakthrough for the management of COVID-19. Finally, we suggest that targeting the ACE2 (a master regulator) in a balanced way could serve as a potential option against the management of COVID-19.

Antiviral Drugs and Vaccines for Omicron Variant: A Focused Review

The Omicron variant of concern (VOC) replaced the delta variant rapidly and became the predominant strain due to more mutations in spike protein and receptor-binding domain (RBD) enhancing its infectivity and binding affinity. The severity of the illness is less than that of the delta variant. Omicron is nonsusceptible to REGEN-COV™ and bamlanivimab with etesevimab. Drugs that are effective against the Omicron variant are oral antiviral drugs such as Paxlovid (nirmatrelvir/ritonavir), remdesivir, sotrovimab, and molnupiravir. The potency of sotrovimab is reduced to 3-fold against Omicron, and 8-fold reduction in potency with sotrovimab is found in a particular variant of Omicron with a R346K substitution in spike protein. There are neither clinical trials comparing the efficacy of these 4 therapies with each other nor any data on a combination of two or more therapies. The current recommendation for mild-moderate, nonhospitalized patients who are at a high risk of disease progression is to use Paxlovid as the first-line option. If Paxlovid is not available or cannot be administered due to drug interactions, then the next best choice is sotrovimab. The third choice is remdesivir if sotrovimab is also not available and molnupiravir is to be given if the other three options are not available or cannot be administered. For prevention, 2130 (cilgavimab) in combination with COV2-2196 (tixagevimab) has been effective against BA.2 only. LY-CoV1404 (bebtelovimab) is recently authorized as it is effective against all sublineages of the Omicron variant. Regarding vaccine efficacy (VE), the 3-dose VE with mRNA vaccines at 14-60 days was found to be 71.6%, and after 60 days, it is 47.4%. There is a 34-38-fold reduction of neutralizing activity with prebooster sera and a 19-fold reduction with booster sera for the Omicron variant. This probably explains the reason for worldwide breakthrough infections with the Omicron variant with waning immunity. The neutralizing antibody response against Omicron elicited by the bivalent vaccine is superior to that of the ancestral Wuhan strain, without any safety concerns. For future advances, the ribosome display technology can be applied for the generation of human single-chain fragment variable (scFv) antibodies from B cells of recovered patients against Omicron and other Coronavirus variants as they are easier and faster to produce and have high affinity and high specificity.

Prevalence and Circulating Serotypes of Dengue in Bastar, Chhattisgarh: A Cross-Sectional Study

The dengue virus is a significant re-emerging arbovirus drawing global public health concern. Urbanization, population growth, human mobility, water access, and storage practices contribute to its transmission. This hospital-based cross-sectional study is designed to determine dengue infection and prevalence in the district Bastar, Chhattisgarh. Blood samples were collected from the patients, and based on fever duration, they were tested for nonstructural protein 1 (NS1) antigen and immunoglobulin M (IgM) antibody detection. NS1 positive cases were further tested by RT-PCR for serotyping. Among the 2223 collected samples, 2041 were screened for NS1 and 182 for IgM; among them, the positivity was 55 (2.70%) in NS1 and 23 (12.63%) in IgM, respectively. Overall positivity of the dengue cases was 78 (3.51%); however, sex-wise, male and female, dengue positive cases were 45 and 33, respectively. NS1 was positive in 55 cases (70.51%), and IgM in 23 (29.49%) patients. Among these 78 cases, 4 NS1 and 2 IgM cases have shown symptoms of warning signs, while the rest of the cases have shown nonwarning symptoms. Among the 55 NS1 positive cases, the age group (21-60 years) was most affected by 45 (81.81%) DENV cases and the prevalent serotype was DENV-2 in singly and DENV-1 and DENV-2 in combination. The study's serotyping data might signify the early detection and identification of circulating serotypes, which provides valuable insights to clinicians for managing dengue infections. Hence, continuous epidemiological surveillance of DENV in the area is essential to anticipate future heterologous infections and their impact on healthcare. Early detection and vigilant monitoring of patients are crucial for identifying the circulating serotypes of dengue virus, facilitating subsequent epidemiological studies and disease control strategies.

Insight into the Burden of Antimicrobial Resistance among Bacterial Pathogens Isolated from Patients Admitted in ICUs of a Tertiary Care Hospital in India

Intensive care unit (ICU) patients are prone to develop infections by hospital prevalent organisms. The aim of the study was to determine the bacteriological profiles and their drug resistance pattern among different infections in ICU patients of a tertiary care hospital. The record-based retrospective data of culture reports of the patients admitted to all the ICUs of a tertiary care hospital during the period from January 2020 to May 2022 were analyzed. A total of 3,056 samples were obtained from 2308 patients. The infection rate among ICU patients was found to be 53.40%. Isolates belonged equally to males (50.86%) and females (49.14%). The most common culture-positive clinical specimen received was blood (39.08%) followed by respiratory samples (29.45%). Acinetobacter sp. (33.02%) was the most common organism isolated from various clinical specimens, followed by Klebsiella pneumoniae (20.89%), and Escherichia coli (13.8%). More than 80% of Acinetobacter species were found to be resistant to third-generation cephalosporins, aminoglycosides, and carbapenems, whereas minocycline (56.31% S) and colistin (100% S) were the most effective drugs. Klebsiella sp. was found to be more resistant than E.coli, and the least resistance was observed to be tetracycline (43.97%) and doxycycline (55.84%). Among Staphylococcus aureus, 82.78% of strains were methicillin-resistant (MRSA). Vancomycin-resistant Enterococci (VRE) sp. accounted for 16.67% of the isolates. Evidence-based knowledge regarding the local bacterial organisms and their antimicrobial resistance pattern is pivotal in deciding empirical drug therapy, ultimately leading to the management of antimicrobial resistance (AMR).

Comparative Diagnostic of Cervical Tuberculous Lymphadenitis: PCR is a Fast, Efficient, and Improved Diagnostic Approach

METHODS

The study included 100 clinically suspected cases of TBLN. Fine needle aspirate (FNA) samples were processed for cytology staining and cultured on LJ & BACTEC 12B media. The biochemical tests were performed to identify the isolates at the species level. Additionally, for PCR, DNA was extracted and used for the diagnosis and identification of mycobacterial species.

RESULTS

Patients ranged from 2 to 45 years with a mean age of 24.96 ± 9.10 years. Out of 100 patients, 73% had clinical symptoms of weight loss, followed by fever (72%), anorexia (66%), and night sweats (58%). 24% of patients were found to be smear-positive after Ziehl-Neelsen (ZN) staining and statistically highly significant with PCR. On LJ medium 34% and on BACTEC radiometric 45% of samples were smearing positive. Overall, 48% of cases were PCR-positive for TBLN. When compared with culture, the sensitivity and specificity of PCR were 93.75% and 100%, respectively, which are higher than cytology. The true positive predictive value (PPV) and negative predictive value (NPV) were 83.3% and 61.5%, respectively.

CONCLUSION

This study suggests that PCR is a rapid, sensitive, and specific tool for correct diagnosis of TBLN cases as compared to staining and culture which lead to the early and proper management of mycobacterial diseases.

Molecular Characterization of Cefoxitin-Resistant Coagulase-Negative Staphylococci From Frequently Touched Surfaces of Hospital and Urban-Built Environments of Central India

Coagulase-negative staphylococci (CoNS) are the major pathogen (hospital as well as environmental) and their emerging multidrug-resistant (MDR) strains complicate the treatment process. In this study, we investigated the prevalence and antibiotic resistance of CoNS on frequently touched surfaces in hospital and urban built environments (UBEs) in Vidarbha, Maharashtra, India. A total of 200 isolates screened for Staphylococcus species and 55 methicillin-resistant staphylococci isolates were identified, and among them, 19 were classified as cefoxitin-resistant CoNS. These 19 cefoxitin-resistant CoNS isolates were tested for the presence of the mecA gene by conventional PCR and only nine (47.36%) were found to be mecA-positive. mecA-positive strains were tested to check MIC for various antibiotics and three marker gene characteristics, namely, ß-lactamase, cefoxitin screen, and inducible clindamycin resistance via the VITEK 2 system. These strains were 100% resistant to benzylpenicillin and oxacillin, and approximately 50% were resistant to vancomycin. Amplified mecA gene fragments were sequenced, and SNP analysis was performed alongside a standard sequence from Staphylococcus aureus (Acc no. NG_047938.1). In total, among the 466 nucleotides, 386 sequences were found to be invariable, and 80 polymorphic variables were identified (46 singleton variable sites and 34 parsimony information sites). The spread of antibiotic resistance is very common in both UBEs and hospital environments; thus, our study concluded that a surveillance program is recommended for the Vidarbha region for the assessment of co-occurring CoNS and better infection control of the environment for future reduction in contact infection.