Respiratory syndromes among pilgrims: assessment of Health status and interventions to alleviate respiratory Symptoms

Background: Acute respiratory symptoms are the commonest problems faced by pilgrims in Makkah. They could result from overcrowding, physical exhaustion and anxiety. The hot-dry atmospheric air exacerbates the problems. Objectives: The aim of the study was to determine the occurrence of acute respiratory symptoms among Malaysian hall pilgrims Methodology: A cross-sectional study was conducted amongst two thousands Malaysian pilgrims. Survey forms were distributed at Madinatul-hullaj, Jeddah where pilgrims stay on transit before returning to Malaysia. Response to the survey was on voluntary basis. The results were analysed using STAT A version 9.0. The denominator was the number of completed survey forms. Results: 394 pilgrims completed and returned the survey forms; 219 males and 173 were females [2 persons did not state their gender]. Only two (0.5%) pilgrims were younger than 10 years and 51 (13.0%) were above 61 years of age. A large majority received influenza vaccination 278 (72.4%). The common underlying diseases were diabetes 48 (12.2%), asthma 35 (8.9%), prolonged cough 34 (8.6%) and rhinitis 28 (7.1 %). In descending order the occurrence of symptoms and their respective 95% confidence intervals were: cough 91.3% (88.0-93.7), runny nose 79.2% (74.9-82.9), sore throat 57.1% (52.1 -61.9) and fever 59.1% (54.2-63.9). Only 3.6% (2.2-5.9) of pilgrims did not suffer from any of these symptoms. Majority had more than two symptoms and longer than 2 weeks duration. The Malaysian hall pilgrims who had single symptom were 9.3% (6.8-12.6), two symptoms 23.7% (19.7-28.1), three symptoms 25.4% (21.4-30.0), and four symptoms 36.5% (31.9-41.4). Only 1.5% (0. 7-3.3) had had hospitalization due to their illness. Conclusion: Acute respiratory symptoms were remarkably common among Malaysian hall pilgrims. The interventional measures to reduce the" morbidity of respiratory related symptoms should be carried out in future Hall seasons

Nosocomial acinetobacter bacteraemia in HUSM

Acinetoliacter ''IPP is a known nosocomial pathogen causing a wide range of clinical diseases such as pneumonia, wound infeCti_On·and ·bloodstream infections (Bsn. The clinical outcomes of acinetobacter BSI were compared to · other gram negative infections. The crude mortality ofacinetobacter BSI was 47.2%, which was signitlcantly greater than other gfafn .. negative BSI. We found that patients treated in intensive care units (ICU), who had longer ICU stays, who preSented with shock or coagulopathy, had prior exposure to carbapenems, had mechanical ventilation, were on a ventilator tbr longer periods, had a nasogastric tube, had an arterial catheter or had parenteral nutrition at a significantly greatei- risk of mortality due to acinetobacter BSL Patients presenting with septic shock or having a central venous catheter were independently at higher risk for mortality. Appropriateness of therapy reduced the mortality attributes of acinetobacter BSJ but did not significantly reduce crude mortality in acinetobacter BSJ patients. This study shows the importance of preventing acinetobacter BSI and the appropriate use of antimicrobial agents to reduce mortality

Structural Evaluation of the Spike Glycoprotein Variants on SARS-CoV-2 Transmission and Immune Evasion

From MDPI via Jisc Publications RouterHistory: accepted 2021-07-07, pub-electronic 2021-07-10Publication status: PublishedFunder: Universiti Sains Malaysia; Grant(s): 1001/PPSP/8012382Abstract: The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents significant social, economic and political challenges worldwide. SARS-CoV-2 has caused over 3.5 million deaths since late 2019. Mutations in the spike (S) glycoprotein are of particular concern because it harbours the domain which recognises the angiotensin-converting enzyme 2 (ACE2) receptor and is the target for neutralising antibodies. Mutations in the S protein may induce alterations in the surface spike structures, changing the conformational B-cell epitopes and leading to a potential reduction in vaccine efficacy. Here, we summarise how the more important variants of SARS-CoV-2, which include cluster 5, lineages B.1.1.7 (Alpha variant), B.1.351 (Beta), P.1 (B.1.1.28/Gamma), B.1.427/B.1.429 (Epsilon), B.1.526 (Iota) and B.1.617.2 (Delta) confer mutations in their respective spike proteins which enhance viral fitness by improving binding affinity to the ACE2 receptor and lead to an increase in infectivity and transmission. We further discuss how these spike protein mutations provide resistance against immune responses, either acquired naturally or induced by vaccination. This information will be valuable in guiding the development of vaccines and other therapeutics for protection against the ongoing coronavirus disease 2019 (COVID-19) pandemic

Diagnostic accuracy of rapid antigen test kits for detecting SARS-CoV-2:a systematic review and meta-analysis of 17,171 suspected COVID-19 patients

Early diagnosis is still as crucial as the initial stage of the COVID-19 pandemic. As RT-PCR sometimes is not feasible in developing nations or rural areas, health professionals may use a rapid antigen test (RAT) to lessen the load of diagnosis. However, the efficacy of RAT is yet to be investigated thoroughly. Hence, we tried to evaluate the overall performance of RAT in SARS-CoV-2 diagnosis. Based on our PROSPERO registered protocol (CRD42021231432), we searched online databases (i.e., PubMed, Google Scholar, Scopus, and Web of Science) and analysed overall pooled specificity and sensitivity of RAT along with study quality, publication bias, heterogeneity and more. The overall pooled specificity and sensitivity of RAT were detected as 99.4% (95% CI: 99.1–99.8; I2 = 90%) and 68.4% (95% CI: 60.8–75.9; I2 = 98%), respectively. In subgroup analyses, nasopharyngeal specimens and symptomatic patient’s samples were more sensitive in RAT, while cycle threshold (Ct) values were found to have an inverse relationship with sensitivity. In the European and American populations, RAT showed better performance. Although the sensitivity of RAT is yet to be improved, it could still be an alternative in places with poor laboratory set up. Nevertheless, the negative samples of RAT can be re-tested using RT-PCR to reduce false negative results

Pharmacodynamics of Polymyxins and Their Combinations with Carbapenems against Multidrug-Resistant Klebsiella pneumoniae

Emergence of antibiotic-resistant bacteria and dearth of new chemical agents in the antibiotics development pipeline present a major medical challenge. The Infectious Diseases Society of America (IDSA) launched the “Bad Bugs, No Drugs” campaign in 2004 to bring attention to the USA policy makers on this unmet medical need. In the 2000s, the global spread of <i>Klebsiella pneumoniae </i>carbapenemase and New Delhi metallo-β-lactamase-producing <i>Enterobacteriaceae</i> (mainly <i>K. pneumoniae</i>) significantly further reduced the choice of antibiotics in the clinic as these pathogens are usually resistant to almost all clinically available antibiotics except polymyxins.<br> <br>    Polymyxins were discovered more than fifty years ago and had never been subjected to modern drug discovery procedures until recently. Two polymyxins are available for clinical use, polymyxin B and colistin (polymyxin E). Polymyxins were ignored from clinical practice from the 1970s due to toxicity and availability of ‘safer’ antibiotics. With no new antibiotic candidate against Gram-negative bacteria in near future, there is an urgent need to optimize the use and understand the mechanism of activity of polymyxins to prolong its therapeutic utility.<br> <br>    In the first experimental chapter of this thesis, the antibacterial activity of colistin-doripenem combination regimens against MDR <i>K. pneumoniae</i> was examined in an <i>in vitro</i> one-compartment pharmacokinetic/pharmacodynamic (PK/PD) model. The colistin-doripenem combination at clinically achievable concentrations substantially increased bacterial killing against colistin-susceptible and -heteroresistant isolates at both low and high initial inocula. Emergence of colistin-resistant subpopulations in colistin-susceptible and -heteroresistant isolates was generally eliminated by combination regimens.<br> <br>    In the second experimental chapter of the thesis, the mode of action of polymyxins was investigated. The activity of polymyxins and their analogues were examined for their ability to inhibit the type II NADH-quinone oxidoreductases (NDH-2) in the respiratory chains of Gram-negative bacteria. Polymyxin B and colistin inhibited the NDH-2 activity in a concentration-dependent manner using inner membrane preparations of <i>K. pneumoniae </i>(colistin-susceptible and resistant variants), <i>Escherichia coli</i> and <i>Acin</i><i></i><i>etobacter baumannii.</i> These findings suggest that a novel secondary mode of action of polymyxins involves the inhibition of bacterial respiratory enzymes in the Gram-negative bacterial inner membrane.<br> <br>    In the third experimental chapter, the surface components of polymyxin-susceptible and resistant variants of <i>K. pneumoniae</i> were examined by a number of biophysical tests. Comparing to the polymyxin-susceptible parent strain, the polymyxin-resistant variant displayed lower negative surface charges, greater outer membrane permeability and less sensitivity to the lytic action of lysozyme and sodium deoxycholate after colistin exposure. The binding affinity of polymyxin B and colistin to LPS purified from wild type was higher than the binding to LPS from the resistant variant. Taken together, a secondary mechanism of polymyxin resistance is believed due to diminished initial electrostatic contacts with the outer membrane that led to reduced killing activity.<br> <br>    In the fourth experimental chapter of this thesis, the uptake of polymyxins by live <i>K. pneumoniae</i> cells was observed under time-lapse laser scanning confocal microscopy using a novel polymyxin-dansyl probe that possessed native antibacterial activity. The polymyxin probe initially accumulated in the outer membrane and subsequently penetrated the inner membrane and finally entered into the cytoplasm. These findings indicated this platform can be employed for the discovery of novel polymyxin-like lipopeptides with efficacy against polymyxin-resistant strains.<br> <br>    Lastly, colistin-doripenem combinations were examined in a non-neutropaenic <i>K. pneumoniae</i> bacteremic mouse model to simultaneously examine bactericidal and endotoxin neutralization effects. Beside the susceptible reference isolate, the efficacy of colistin-carbapenem combination was evaluated for the first time against globally disseminated NDM-1-producer carbapenem-resistant isolate in an animal model. The combination therapy resulted in lower bacterial counts against both isolates, compared to colistin or doripenem monotherapy. Significant lower endotoxin level was observed in mice treated with colistin-doripenem combination therapy against the NDM-1-producer, compared to the control or any monotherapy groups. Against the NDM-1-producer this combination therapy led to significant lower TNF levels compared to the untreated control. These findings demonstrated that the colistin-doripenem combination is useful for the treatment of sepsis caused by NDM-1-producing <i>K. pneumoniae.<br> </i><br>    In summary, this thesis provides novel information on the optimal use and the mechanism of activity of polymyxins against <i>K. pneumoniae.</i> Colistin-doripenem combination was synergistic and able to suppress the emergence of polymyxin resistance in MDR <i>K. pneumoniae</i> infections. In non-neutropenic bacteraemic mice caused by an NDM-1-producer carbapenem-resistant <i>K. pneumoniae,</i> a significant reduction was evident in the bacterial load and endotoxin activity after treatment with colistin-doripenem combination. This study provides important information on the strategies to maximise the efficacy of polymyxins. This thesis is also the first to report the inhibition of NDH-2 respiratory enzymes in Gram-negative by polymyxins, supported by the microscopic observation of accumulation and penetration of the native polymyxin-like probe in the cell membrane. This secondary target of polymyxins is still vulnerable in polymyxin-resistant <i>K. pneumoniae</i> strains; therefore, it can be exploited for the development of new lipopeptide antibiotics targeting polymyxin-resistant bacteria

In Silico Molecular Characterization of Human TMPRSS2 Protease Polymorphic Variants and Associated SARS-CoV-2 Susceptibility

The 2019 coronavirus disease (COVID-19) pandemic continues to challenge health care systems worldwide. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been responsible for the cause of global pandemic. Type 2 transmembrane serine protease (TMPRSS2) is important in the cell entry and spread of SARS-CoV-2 and plays a crucial role in the proteolytic cleavage of SARS-CoV-2 spike (S) glycoprotein. Here, using reported structural data, we analyzed the molecular complex of TMPRSS2 and the S glycoprotein and further examined intermolecular interactions of natural TMPRSS2 polymorphic variants. We identified several TMPRSS2 variants that could possibly alter host susceptibility to the SARS-CoV-2 infection. Molecular docking analysis revealed that G462D/G462S variants were predicted to be protective variants, whereas Q438E and S339F variants were predicted to increase susceptibility. In addition, we examined intermolecular interactions between TMPRSS2 and its two potential serine protease inhibitors, camostat mesylate and nafamostat. Further, we investigated the effect of TMPRSS2 variants on these interactions. Our structural analysis revealed that G462D, C297S and S460R variants had possibly altered the interactions with the protease inhibitors. Our results identified important TMPRSS2 variations that could be useful to develop high affinity and personalized drugs for treating COVID-19 patients

Structural Insights into Substrate Binding and Antibiotic Inhibition of Enterobacterial Penicillin-Binding Protein 6

Shigella sonnei remains the second most common cause of shigellosis in young children and is now increasingly dominant across developing countries. The global emergence of drug resistance has become a main burden in the treatment of S. sonnei infections and &beta;-lactam antibiotics, such as pivmecillinam and ceftriaxone, are recommended to be used as second-line treatment. They work by inhibiting the biosynthesis of the peptidoglycan layer of bacterial cell walls, in which the final transpeptidation step is facilitated by penicillin-binding proteins (PBPs). In this study, using protein homology modelling, we modelled the structure of PBP6 from S. sonnei and comprehensively examined the molecular interactions between PBP6 and its pentapeptide substrate and two antibiotic inhibitors. The docked complex of S. sonnei PBP6 with pentapeptides showed that the substrate bound to the active site groove of the DD-carboxypeptidase domain, via hydrogen bonding interactions with the residues S79, V80, Q101, G144, D146 and R240, in close proximity to the catalytic nucleophile S36 for the nucleophilic attack. Two residues, R240 and T208, were found to be important in ligand recognition and binding, where they formed strong hydrogen bonds with the substrate and &beta;-lactams, respectively. Our results provide valuable information on the molecular interactions essential for ligand recognition and catalysis by PBP6. Understanding these interactions will be helpful in the development of effective drugs to treat S. sonnei infections