Infectious Organisms Research Articles

A framework for predicting variable-length epitopes of human-adapted viruses using machine learning methods

The coronavirus disease 2019 pandemic has alerted people of the threat caused by viruses. Vaccine is the most effective way to prevent the disease from spreading. The interaction between antibodies and antigens will clear the infectious organisms from the host. Identifying B-cell epitopes is critical in vaccine design, development of disease diagnostics and antibody production. However, traditional experimental methods to determine epitopes are time-consuming and expensive, and the predictive performance using the existing in silico methods is not satisfactory. This paper develops a general framework to predict variable-length linear B-cell epitopes specific for human-adapted viruses with machine learning approaches based on Protvec representation of peptides and physicochemical properties of amino acids. QR decomposition is incorporated during the embedding process that enables our models to handle variable-length sequences. Experimental results on large immune epitope datasets validate that our proposed model's performance is superior to the state-of-the-art methods in terms of AUROC (0.827) and AUPR (0.831) on the testing set. Moreover, sequence analysis also provides the results of the viral category for the corresponding predicted epitopes with high precision. Therefore, this framework is shown to reliably identify linear B-cell epitopes of human-adapted viruses given protein sequences and could provide assistance for potential future pandemics and epidemics.

In Vitro Effect of 5-Nitroimidazole Drugs against Trichomonas vaginalis Clinical Isolates.

ABSTRACTInfections with the sexually transmitted parasite Trichomonas vaginalis are normally treated with metronidazole, but cure rates are suboptimal and recurrence rates following treatment are high. Therefore, our objective was to assess the in vitro antitrichomonas activities of three other 5-nitroimidazole drugs and compare them with metronidazole. T. vaginalis isolates (n = 94) isolated from South African women presenting with vaginal discharge syndrome at two sexually transmitted disease clinics in KwaZulu-Natal were grown from frozen stock. Twofold serial dilutions (16 to 0.25 mg/L) of metronidazole, tinidazole, ornidazole, and secnidazole were prepared in Diamond’s broth. The MICs were read after 48 h of anaerobic incubation at 37°C. An MIC of <2 mg/L was defined as susceptible, an MIC of 2 mg/L was defined as intermediate, and an MIC of >2 mg/L was defined as resistant. Sixty-one percent (57/94) of the T. vaginalis isolates were susceptible to metronidazole, 80% (75/94) were susceptible to tinidazole, 75% (71/94) were susceptible to secnidazole, and 89% (84/94) were susceptible to ornidazole. Resistance levels were 11%, 2%, and 1% for metronidazole, tinidazole, and secnidazole, respectively, while no resistance was observed for ornidazole. Intermediate scores were 28% for metronidazole, 18% for tinidazole, 24% for secnidazole, and 11% for ornidazole. Isolates from a proportion of women with bacterial vaginosis (BV) had higher MICs, and no isolates from women coinfected with another sexually transmitted infectious organism were resistant to any of the antimicrobials tested. This study showed that among T. vaginalis isolates in KwaZulu-Natal, there is no in vitro resistance to ornidazole. Of the 5-nitroimidazoles, metronidazole showed the highest level of resistance. The very low levels of resistance for the other three antimicrobials indicate that all three are viable options as a replacement for metronidazole if these in vitro findings are found to correlate with clinical outcomes.IMPORTANCE Trichomonas vaginalis is the most common nonviral sexually transmitted infection associated with reproductive sequelae and HIV acquisition risk worldwide. Despite its role in reproductive health, a high prevalence in South Africa, and the reported metronidazole resistance worldwide, no alternative regimens have been tested against T. vaginalis in our setting. This study compared the susceptibility patterns of three other 5-nitroiminazoles (secnidazole, tinidazole, and ornidazole), which are active against T. vaginalis with metronidazole in vitro. Metronidazole, the drug of choice for the treatment of trichomoniasis, showed the highest level of resistance, while the three regimens showed very low levels of resistance. These data indicate that all three are viable options as a replacement for metronidazole if these in vitro findings are found to correlate with clinical outcomes.

Non-diphtheriae Corynebacteria Causing Breast Abscess in Non-lactating Females Seeking to Avoid Pitfalls in Diagnosis of Chronic Breast Infections Through Diagnostic Stewardship

Background: Consideration of non-diphtheriae Corynebacteria as an infective organism in mastitis, is usually neglected. So, infections due to Corynebacterium species may remain undiagnosed or misdiagnosed. The aim of our study was to focus on non-diphtheriae Corynebacterium as causative organisms in breast infections using scientific logic and technology of Matrix Assisted Laser Desorption Ionisation Time of Flight Mass Spectrometry (MALDITOF MS) to categorize the isolates upto species level. The clinical correlation and response to management especially targeted antimicrobials was also recorded.&#x0D; Methods: All the consecutive pus/tissue samples from Breast abscess received during study period were processed as per the standard guidelines. The identification of the isolate was done by automated methods. The cytopathological/histopathological and clinical details of the patients with infection due to Corynebacterium sp. were recorded and analyzed.&#x0D; Results: Out of 52 non-duplicate samples, five showed growth of non-diphtheriae Corynebacteria. These were identified as C. kroppenstedtii and C. amycolatum. The antimicrobial susceptibility testing showed 100% susceptibility to Amoxicillin-clavulanate, Tetracycline, Vancomycin and Linezolid for all the five isolates. Histopathological examination was suggestive of chronic inflammatory mastitis/Granulomatous mastitis.&#x0D; Conclusion: Non diphtheriae Corynebacteria particularly lipophilic Corynebacteria have a predilection to cause infections of breast tissue and Breast abscess which may mimic as tubercular abscess or chronic non-specific mastitis leading to unnecessary usage of antimicrobials. So, these isolates from breast tissue/pus should not be ignored rather definitely identified. This would also ensure diagnostic stewardship.

Environmental Persistence of the World's Most Burdensome Infectious and Parasitic Diseases.

Humans live in complex socio-ecological systems where we interact with parasites and pathogens that spend time in abiotic and biotic environmental reservoirs (e.g., water, air, soil, other vertebrate hosts, vectors, intermediate hosts). Through a synthesis of published literature, we reviewed the life cycles and environmental persistence of 150 parasites and pathogens tracked by the World Health Organization's Global Burden of Disease study. We used those data to derive the time spent in each component of a pathogen's life cycle, including total time spent in humans versus all environmental stages. We found that nearly all infectious organisms were “environmentally mediated” to some degree, meaning that they spend time in reservoirs and can be transmitted from those reservoirs to human hosts. Correspondingly, many infectious diseases were primarily controlled through environmental interventions (e.g., vector control, water sanitation), whereas few (14%) were primarily controlled by integrated methods (i.e., combining medical and environmental interventions). Data on critical life history attributes for most of the 150 parasites and pathogens were difficult to find and often uncertain, potentially hampering efforts to predict disease dynamics and model interactions between life cycle time scales and infection control strategies. We hope that this synthetic review and associated database serve as a resource for understanding both common patterns among parasites and pathogens and important variability and uncertainty regarding particular infectious diseases. These insights can be used to improve systems-based approaches for controlling environmentally mediated diseases of humans in an era where the environment is rapidly changing.

Hospital water as the source of healthcare-associated infection and antimicrobial-resistant organisms.

Drinking water is considered one of the most overlooked and underestimated sources of healthcare-associated infections (HAIs). Recently, the prevention and control of opportunistic premise plumbing pathogens (OPPPs) in healthcare water systems has been receiving increasing attention in infection control guidelines. However, these fail to address colonization of pathogens that do not originate from source water. Subsequently, this review explores the role of water and premise plumbing biofilm in HAIs. The potential mechanisms of contamination and transmission of antimicrobial-resistant (AMR) pathogens originating both from supply water and human microbiota are discussed. OPPPs, such as Legionella pneumophila, Pseudomonas aeruginosa and Mycobacterium avium have been described as native to the plumbing environment. However, other pathogens, not found in the source water, have been found to proliferate in biofilms formed on outlets devices and cause HAI outbreaks. Biofilms formed on outlet devices, such as tap faucets, showers and drains provide an ideal niche for the dissemination of antimicrobial resistance. Thus, comprehensive surveillance guidelines are required to understand the role that drinking water and water-related devices play in the transmission of AMR HAIs and to improve infection control guidelines.

Microbiological Profile and Drug Resistance Analysis of Postoperative Infections following Orthopedic Surgery: A 5-Year Retrospective Review.

Background The distribution of postoperative orthopedic infection and their susceptibility pattern to antibiotics vary regionally and change over time. The incidence of methicillin-resistant Staphylococcus aureus infection is rising worldwide. Therefore, knowledge of the frequency of the causative microorganisms and their susceptibility to antibiotics are necessary for an improved therapeutic outcome. This study aims to study the frequency and distribution of postoperative orthopedic infection and their resistance pattern to antibiotics. Methods The study utilized a retrospective design that took place over a period of 5 years from 2016 and 2020 at a tertiary care hospital. The bacterial culture testing was performed by a recommended method. Descriptive statistics were used to analyze the data. Results A total of 158 patients (100 males and 58 females) with positive cultures of postoperative orthopedic infection were included. The most common infective organism was Staphylococcus aureus, 64 patients (38.1%); coagulase-negative staphylococci, 40 patients (23.8%); Klebsiella species, 14 patients (8.3%); and Enterococcus species, Escherichia coli, and Pseudomonas aeruginosa in 10 patients (6%). Data also showed that gram-positive bacteria were detected in 118 patients (70.8%), while gram-negative microorganisms were found in 50 patients (29.8%). Among Staphylococcus aureus, 79.7% were MRSA, and vancomycin was the most effective antibiotic in staphylococcus infections. The antibiotics with the greatest sensitivity to gram-positive bacteria were vancomycin, linezolid, tigecycline, moxifloxacin, and nitrofurantoin, while the antibiotics for gram-negative bacteria with greater sensitivity were tigecycline, amikacin, ertapenem, imipenem, and cefotaxime. Conclusion Staphylococcus aureus is the most common postoperative orthopedic infection, which was predominantly MRSA with vancomycin being the most effective antibiotic. In addition, the results showed a high resistance pattern to the commonly used antibiotics, leaving few choices. Antibiotic agents should be carefully selected according to specific drug sensitivity through routine monitoring of drug resistance patterns and to help formulate hospital antibiotic policy.

Risk Factors of Pneumonia in Primary Antibody Deficiency Patients Receiving Immunoglobulin Therapy: Data from the US Immunodeficiency Network (USIDNET).

Despite immunoglobulin replacement (IgRT) therapy, some patients with primary antibody deficiency (PAD) continue to develop respiratory infections. Recurrent and severe respiratory infections, particularly pneumonia, can lead to significant morbidity and mortality. Therefore, we sought to determine the risk factors of developing pneumonia in PAD patients, already receiving IgRT. We evaluated clinical and laboratory features of PAD patients enrolled in the US Immune Deficiency Network (USIDNET) registry by April 2017. Patients were included if they met the following criteria: (1) PAD diagnosis (common variable immunodeficiency (CVID), agammaglobulinemia, hypogammaglobinemia, and specific antibody deficiency (SAD) and (2) available data on infections before and after IgRT. Patients were excluded if they were not receiving IgRT, or if no pre/post infections data were available. Descriptive and multivariable logistic regression analyses were used to identify factors associated with pneumonia post-IgRT. A total of 1232 patients met the inclusion criteria. Following IgRT, 218 patients (17.7%) were reported to have at least one pneumonia episode. Using multivariate logistic regression analysis, we found a statistically significant increased risk of pneumonia in patients with asthma (OR: 2.55, 95% CI (1.69-3.85), p < 0.001) bronchiectasis (OR: 3.94, 95% CI (2.29-6.80), p < 0.001), interstitial lung disease (ILD) (OR: 3.28, 95%CI (1.43-7.56), p < 0.005), splenomegaly (OR: 2.02, 95%CI (1.08-3.76), p < 0.027), allergies (OR: 2.44, 95% CI [1.44-4.13], p = 0.001), and patients who were not on immunosuppressives (OR: 1.61; 95%CI [1.06-2.46]; p = 0.027). For every 50 unit increase in IgA, the odds of reporting pneumonia post IgRT decreased (OR: 0.86, 95% CI [0.73-1.02], p = 0.062). Infectious organisms were reported in 35 of 218 patients who reported pneumonia after IgRT. Haemophilus influenzae was the most frequently reported (n = 11, 31.43%), followed by Streptococcus pneumoniae (n = 7, 20.00%). Our findings suggest PAD patients with chronic and structural lung disease, splenomegaly, and allergies were associated with persistent pneumonia. However, our study is limited by the cross-sectional nature of the USIDNET database and limited longitudinal data. Further studies are warranted to identify susceptible causes and explore targeted solutions for prevention and associated morbidity and mortality. Patients with primary antibody deficiency with structural lung disease, allergies, and splenomegaly are associated with persistent pneumonia post-IgRT.

Tight Junctions, the Epithelial Barrier, and Toll-like Receptor-4 During Lung Injury.

Lung epithelium is constantly exposed to the environment and is critically important for the orchestration of initial responses to infectious organisms, toxins, and allergic stimuli, and maintenance of normal gaseous exchange and pulmonary function. The integrity of lung epithelium, fluid balance, and transport of molecules is dictated by the tight junctions (TJs). The TJs are formed between adjacent cells. We have focused on the topic of the TJ structure and function in lung epithelial cells. This review includes a summary of the last twenty years of literature reports published on the disrupted TJs and epithelial barrier in various lung conditions and expression and regulation of specific TJ proteins against pathogenic stimuli. We discuss the molecular signaling and crosstalk among signaling pathways that control the TJ structure and function. The Toll-like receptor-4 (TLR4) recognizes the pathogen- and damage-associated molecular patterns released during lung injury and inflammation and coordinates cellular responses. The molecular aspects of TLR4 signaling in the context of TJs or the epithelial barrier are not fully known. We describe the current knowledge and possible networking of the TLR4-signaling with cellular and molecular mechanisms of TJs, lung epithelial barrier function, and resistance to treatment strategies.

Guillain–Barre Syndrome Following SARS-CoV-2 Infection in Children

Background: Guillain–Barre Syndrome (GBS) is an autoimmune polyneuropathy involving mainly motor but also sensory and autonomic nerves. It is considered postinfectious and is been linked with many infectious organisms such as human immunodeficiency virus, Zika virus, and others. Since the onset of the pandemic, a few cases of GBS with a temporal association with SARS-CoV-2 infection has been reported in adults and children. The manifestations are similar to the classic clinical phenotype of progressive, ascending, symmetrical flaccid paralysis of the limbs with areflexia/hyporeflexia, and with or without cranial nerve involvement. This series describe three children with post-COVID GBS. Case Description: Three unrelated boys, 14 years, 11 years, and 7 years in age presented with varying combinations of pain, paraesthesias, and ascending weakness involving their limbs for a few days. We suspected GBS based on the clinical phenotype of rapidly progressive symmetrical weakness. The Modified National Institute of Neurological Disorders and Stroke Criteria for establishing the clinical diagnosis of GBS were satisfied. The typical albuminocytological dissociation in cerebrospinal fluid was observed in all. Management: The GBS was presumed to be postinfectious secondary to the COVID-19 virus in each one, based on elevated COVID-19 immunoglobulin G (IgG) and IgM antibody titers, exclusion of other common infectious organisms, and normal magnetic resonance imaging. All these patients were started on intravenous immunoglobulin and methylprednisolone. Two children recovered without any neurological deficits. The third child expired due to respiratory involvement. Conclusion: COVID-19 infection may result in GBS, the clinical profile of which is similar to that seen after other infectious organisms.

To Assess the Clinical Radiological and Microbiological Profile of Patients with Community Acquired Pneumonia in a Tertiary Care Center in North East India and the Factors Predicting Mortality

Background: Pneumonia is an acute inflammation of the pulmonary parenchyma caused by various infective organisms. This study was intended in studying from 14 to 90 years with a mean age of 58.8 ± 15.73 years. Severity assessment is recognised as a pivotal step in the management of CAP. This study was intended in identifying prognostic factors to predict the mortality. The majorities (60%) of the patients were males and 40% were females. Out of 150 patients, 90(60%) were admitted to general wards and 60(40%) were admitted to the ICU. Out of the 60 patients admitted to the ICU, 45(75%) required Mechanical Ventilation. And out of these, 18 patients (12%) died. Conclusion: Demographic factors like male sex and elderly age group, clinical profile of confusion, dyspnea, tachypnea, tachycardia and hypotension, laboratory parameters of hypoalbuminemia, leucopenia, elevated BUN, hyperglycemia, high serum LDH, high CRP, acidosis, hypoxia, hypercapnea, growth of klebsiella and pseudomonas species on sputum culture and multilobar involvement on chest radiology also were associated with higher mortality.

Liquid Based Pap Smears for Detection of Infective Organisms in a Tertiary Care Hospital

Background: Bacterial vaginosis (BV), vulvovaginal candidiasis (VVC) and trichomonal vaginitis (TV) are the most common etiologies of infective vaginitis. The Papanicolaou (Pap) smear is a standard screening test for cervical precancerous lesions that can also be useful to identify infective organisms. This study aimed to identify the causativeorganisms for cervico-vaginal infection in liquid-based Pap smears. Methods: This study was a cross sectional study and included 370 liquid based Pap smears with infective organisms. Results: The most prevalent cervico-vaginal infection was BV, which was detected in 259 (70%) of the cases, followed by VVC in 64 (17.3%) and TV in 25 (6.8%) cases.Women aged 30-39 years were mostlyaffected. Conclusion: The present study shows the usefulness of cervical Pap smear in diagnosis of infective vaginitisother than epithelial cell abnormalities.

Predicting severity of periorbital necrotizing fasciitis

ABSTRACT Purpose To determine whether severity of periorbital necrotizing fasciitis can be predicted based on premorbid patient characteristics. Methods Records of 10 consecutive patients with periorbital necrotizing fasciitis presenting at a single center, treated by one attending ophthalmic plastic surgeon, were retrospectively reviewed. Demographic information and medical history were used to determine a Charlson Comorbidity Index (CCI) score for each patient. Other variables included presenting visual acuity, number of surgical debridements performed, infectious organism (if known), and visual acuity at last follow-up. Data were compared with Mann–Whitney U test to determine correlation between variables, using p-values as outcome measures. Results Increased age at presentation correlated with worse presenting and final visual acuity, requiring more surgical debridements to control disease (each p < .0001). Worse initial visual acuity correlated with need for increased number of debridements (p = .002), but increased number of debridements did not correlate with final visual acuity (p = .101). CCI did not correlate with initial vision (p = .30), final vision (p = .72), or number of surgical debridements necessary (p = .99). Presenting visual acuity did not correlate with final visual acuity (p = .268). Conclusion Older patients have more severe cases of periorbital necrotizing fasciitis, as defined by increased number of surgeries required to control disease and worse visual outcomes. CCI did not correlate with severity of disease.

IgM+ and IgM- memory B cells represent heterogeneous populations capable of producing class-switched antibodies and germinal center B cells upon rechallenge with P. yoelii.

Memory B cells (MBCs) are essential for maintaining long-term humoral immunity to infectious organisms, including Plasmodium. MBCs are a heterogeneous population whose function can be dictated by isotype or expression of particular surface proteins. Here, aided by antigen-specific B-cell tetramers, MBC populations were evaluated to discern their phenotype and function in response to infection with a nonlethal strain of P. yoelii. Infection of mice with P. yoelii 17X resulted in 2 predominant MBC populations: somatically hypermutated isotype-switched (IgM- ) and IgM+ MBCs that coexpressed CD73 and CD80 that produced antigen-specific antibodies in response to secondary infection. Rechallenge experiments indicated that IgG-producing cells dominated the recall response over the induction of IgM-secreting cells, with both populations expanding with similar timing during the secondary response. Furthermore, using ZsGreen1 expression as a surrogate for activation-induced cytidine deaminase expression alongside CD73 and CD80 coexpression, ZsGreen1+ CD73+ CD80+ IgM+ , and IgM- MBCs gave rise to plasmablasts that secreted Ag-specific Abs after adoptive transfer and infection with P. yoelii. Moreover, ZsGreen1+ CD73+ CD80+ IgM+ and IgM- MBCs could differentiate into B cells with a germinal center phenotype after adoptive transfer. A third population of B cells (ZsGreen1- CD73- CD80- IgM- ) that is apparent after infection responded poorly to reactivation in vitro and in vivo, indicating that these cells do not represent a canonical population of MBCs. Together these data indicated that MBC function is not defined by immunoglobulin isotype, nor does coexpression of key surface markers limit the potential fate of MBCs after recall.

A STUDY OF PREVALENCE AND ANTIMICROBIAL SUSCEPTIBILITY PATTERN OF NON FERMENTER GRAM NEGATIVE BACILLI ISOLATED FROM VARIOUS CLINICAL SAMPLES AT A TERTIARY CARE CENTER, JAIPUR

Introduction: Non-fermentative Gram-negative bacilli (NFGNB) are occasionally involved in infectious diseases pathology, but have shown resistance to multiple antibiotics and the capability to gain new resistance factors in the hospital environment. The present study was aimed to investigate the prevalence of Metallo-beta-lactamase (MBL) producing non-fermenters among the carbapenem-resistant isolates. AMethods: total of 200 NFGNB isolates from various clinical samples were analyzed by using different standard microbiological techniques and antimicrobial susceptibility using Kirby-Bauer method. MBL detection was performed by Modied Hodge test (MHT), imipenem-EDTA combined disc test, and modied Carbapenemase inactivation method (mCIM). In our study, 200 NFGNB isolates recovered from various clinical samples.Results: Pseudomonas aeruginosa was the most common NFGNB, accounting 112 (56%), followed by Acinetobacter baumannii 56 (28%), Burkholderia species 26 (13%) and other rare nonfermenter Gram negative bacilli 6 (3%). NFGNB isolates were maximally isolated from blood samples 73 (36.5%) followed by respiratory samples 46 (23%), urine 40 (20%), pus 37 (18.5%) and CSF 4 (2%). All the NFGNB isolates were susceptible to polymyxin B, colistin (100%), and cefoperazone + sulbactam (45.53%). Out of 112 Pseudomonas isolates, 77(68.75%) were imipenem resistant and of 56 Acinetobacter isolates, 35(62.5%) were imipenem resistant. Out of 77 imipenem resistant Pseudomonas 70 (90.9%) were MBL producers and out of 35 imipinem resistant Acinetobacter spp 32 (91.42%) were MBL producers. NFGNB are now emerging asConclusion: organisms of nosocomial infections. The use of broad-spectrum antibiotics should be avoided and quick detection and efcient infection control measures are essential to prevent the further spread of MBLs to other Gram-negative bacilli. Detection of MBL production and rationale antibiotic usage are the most important factors which control the gradually increasing NFGNB related infections

Global prevalence of zoonotic pathogens from pigeon birds: A systematic review and meta-analysis

Pigeons have been considered the most preferred companion for human civilizations since prehistoric times. Despite the fact that pigeons offer the most palatable and nutritious food and provide pleasure to humans, they can pose a health risk because of carrying infectious and zoonotic organisms. Moreover, the scanty of systematic reports on the occurrence of zoonotic pathogens in pigeon makes the situations worst. Hence, the current study conducted a systematic review and meta-analysis to evaluate the global prevalence of zoonotic pathogens among the pigeon population from existing segregated literatures. Four internationally recognized databases including Google Scholar, Scopus, PubMed, and Science Direct were used to search the published studies from January 2000 to October 2021. Analyzing the total 18,589 samples, mean prevalence estimates of pigeon pathogens worldwide were found to be 17% (95% CI:13–21) whereas serological and molecular prevalence were reported as 18% (95% CI:12–23) and 17% (95% CI:10–23). Meanwhile, virus, bacteria, and protozoal pathogens were found to be 21% (10–32%), 17% (12–23%), and 14% (10–19%), respectively. Moreover, continent wise analysis of all zoonotic pigeon pathogens has revealed the highest prevalence rate in Asia 20% (95% CI: 14–26%), followed by Europe 16% (95% CI: 08–24%), Africa 16% (95% CI: 07–24%), and America (North and South) 10% (95% CI: 03–17%). Furthermore, the highest number of studies were reported from Iran showed the prevalence rate of 20%, China 13%, Bangladesh 37%, and Poland 15%. Therefore, this prevalence of data would be helpful to the policymakers to develop appropriate intervention strategies to prevent and control diseases in their respective locations.

Cell Staining.

When labeled antibodies are used to detect antigens in cells or tissues, several characteristics of an antigen can be readily determined. Most importantly, cell staining will show both the presence and subcellular localization of an antigen. Double-labeling techniques permit the simultaneous detection of two antigens, allowing comparisons of the relative distribution of different antigens. Many cell-staining methods can also be used in conjunction with conventional histological stains and autoradiographic methods to compare the localization of the antigen with other markers. Cell staining can also be used in pathology studies for determining such variables as the type of infectious organism, the progenitor of a neoplastic cell, or the presence of an inflammatory response. With certain modifications, the procedure can be used to purify cells on the basis of the antigenic composition of their cell surface. Cell staining is a versatile technique and, if the antigen is highly localized, can detect as few as a thousand antigen molecules in a cell or tissue. In some circumstances, cell staining may also be used to determine the approximate concentration of an antigen. Improvements in antibody labeling methods, microscopes, cameras, and image analyzers are rapidly extending the sensitivity of cell-staining procedures and are making these techniques more quantitative. Even without these improvements, cell staining can yield important qualitative and semiquantitative data. This introduction describes protocols for cell staining techniques and includes a discussion of major constraints, antibody selection, and troubleshooting.

The Assessment of Forensic Disguising Markers for Food Poisoning and their Control Measures. A Health Awareness Study

Aims and objectives: To uncover the disguising markers of food poising and their Control Measures to spread public awareness for betterment of human health through forensic applications. Materials and Methods: Study design: Present study was conducted from December 2021to June 2022 in Lahore. Sample size and collections: Various food samples were collected from 10 different restaurants. 5 different food products were collected from each restaurant for analysis of biological markers while non-biological markers were observed on the location at a data collection Performa. Chemical analysis: In case of food poising the forensic chemical analysis are based on biochemical and physiological tests such as bacterial Count in collected food samples through plate count method and spectrophotometric (turbid metric) analysis. Determined Parameters: In this study both biological parameters, such as bacterial Count and non-biological parameters like, hygiene, quality of water, utensils quality, cooking style and cooking environment were considered. Results presentations: Raw data of each parameter was represented bio-statistically with the applications of SPSS in which regressions of standard mean deviation and significant (P&lt;0.05) were considered comparatively. Results: It has seen that mostly all food samples taken from different restaurants have bacterial flora. These bacterial count may be so harmful for human life. It was concluded by considering non-biological parameters that the hygienic conditions, cooking place and way of cooking were not according to the standard health levels recommended by food authority. Especially quality of raw material and utensils were not standardized. All the results were significant as compared with the given standard levels of each parameter. A remarkable changes were noted in different parameters regarding food quality for further elaboration results are represented graphically in fig-1. Conclusion: Infectious organisms including bacteria, viruses and parasites or their toxins are the most common causes of food poisoning. Infectious organisms or their toxins can contaminate food at any point of processing or production. Contamination can also occur at home if food is incorrectly handled or cooked. Keywords: Bacteria, Viruses, Parasites, Contamination, Food Poisoning.

Global DNA hypomethylation and the expression profile of DNA methyltransferase genes in late-onset neonatal sepsis.

Aim: Infectious organisms tend to cause DNA methylation changes. Thus, this paper aims to study global DNA methylation and the expression of DNA methyltransferase (DNMT)genes in late-onset neonatal sepsis (LONS). Methods: Global and Alu DNA methylation and expression levels of DNMT were performed using 5mc ELISA, methylation-specific PCR and quantitative real-time-PCR, respectively for LONS and controls. Results: Significant hypomethylation of global DNA and Alu DNA methylation and lower expression of DNMT1 and DNMT3a were observed in LONS compared with controls. Receiver operating characteristic analysis of global and Alu DNA methylation showed good discrimination for the identification of LONS. Conclusion: The hypomethylation of global DNA and Alu elements is evident in neonates with LONS. This may be clinically useful for the prognosis of LONS.

Biochemical and Biophysical Characterization of Exoribonucleases from the Human Pathogen Mycobacterium tuberculosis

Mycobacterium tuberculosis remains the leading cause of mortality from a single infectious organism, infecting nearly one-third of the global population. The current emergence of multidrug-resistant strains represents a serious health problem nowadays. Moreover, regulation of gene expression through RNA metabolism is a key mechanism for bacterial growth, division and rapid accommodation to environmental conditions. Ribonucleases are enzymes present in all living organisms that play an important role in RNA processing and degradation. Particularly, ribonucleases belonging to the RNB-family are often essential for viability of prokaryotes and are implicated in the establishment of virulence of several pathogens. In the present study we aim to structurally and functionally characterize two putative exoribonucleases from the RNB-family of enzymes inM. tuberculosis. Overexpression and purification of the proteins was performed and further in vitro activity, binding and helicase assays using synthetic RNA substrates were accomplished. In parallel, a biophysical characterization proceeded with several crystallization trials and protein stability tests. We have demonstrated that both RNases are 3’-5’ exoribonucleases with different degradation properties and unravelled the importance of highly conserved residues for catalysis. Moreover, we were able to identify improved buffer formulations that increase protein stability, possibly enhancing their propensity to crystallize. The information regarding RNA metabolism in M. tuberculosis is limited and RNB-family enzymes have not been previously characterized in this important human pathogen. Thus, a complete knowledge of these ribonucleases is an approach to recognize their influence in M. tuberculosis metabolism and to better understand the post-transcriptional control in this pathogen.

Comparison of the Antimicrobial Efficacy and Germicidal Efficiency of 405-nm Light for Surface Decontamination

Background The persistence of infectious organisms on hospital surfaces presents a significant challenge to healthcare environments. Low irradiance visible 405-nm light has recently been developed as a method for environmental decontamination, with studies demonstrating successful reductions of environmental bacteria in wards and operating theatres. This study investigates the antimicrobial efficacy of 405-nm light for decontamination of surfaces, and how the dose-response kinetics are affected by use of differing light irradiances. Methods Surface-seeded Staphylococcus aureus and Pseudomonas aeruginosa (selected as model Gram-positive and Gram-negative species) were exposed to increasing doses of 405-nm light (≤ 90 Jcm-2) at three discrete irradiances (0.5, 5 and 50 mWcm-2). For both species, inactivation kinetics at each respective irradiance was established and susceptibility at equivalent light doses compared. Results Results demonstrate increased bacterial susceptibility to 405-nm light inactivation when exposed at lower irradiance treatments. For both species, 3 Jcm-2 was required when exposed using 0.5 mWcm-2 irradiance to achieve significant bacterial inactivation (P &lt; 0.05; 26.7-73.7% reduction). When exposed at 5 mWcm-2, double the energy (6 Jcm-2) was required to achieve similar reductions. Exposure at the highest irradiance (50 mWcm-2) required 3-5 times greater dose (9-15 Jcm-2) to achieve similar reductions to the lowest irradiance tested (0.5 mWcm-2). Conclusion This study provides evidence of the enhanced germicidal efficiency of low irradiance 405-nm light, highlighting its efficacy for continuous environmental decontamination applications. Further investigation into the photo-chemical inactivation mechanisms will be crucial for its optimisation for a range of infection control applications.