Case Report: Allergic Bronchopulmonary Aspergillosis Revealing Asthma

Allergic bronchopulmonary aspergillosis (ABPA) is an immunological pulmonary disorder caused by hypersensitivity to Aspergillus which colonizes the airways of patients with asthma and cystic fibrosis. Its diagnosis could be difficult in some cases due to atypical presentations especially when there is no medical history of asthma. Treatment of ABPA is frequently associated to side effects but cumulated drug toxicity due to different molecules is rarely reported. An accurate choice among the different available molecules and effective on ABPA is crucial. We report a case of ABPA in a woman without a known history of asthma. She presented an acute bronchitis with wheezing dyspnea leading to an acute respiratory failure. She was hospitalized in the intensive care unit. The bronchoscopy revealed a complete obstruction of the left primary bronchus by a sticky greenish material. The culture of this material isolated Aspergillus fumigatus and that of bronchial aspiration fluid isolated Pseudomonas aeruginosa. The diagnosis of ABPA was based on elevated eosinophil count, the presence of specific IgE and IgG against Aspergillus fumigatus and left segmental collapse on chest computed tomography. The patient received an inhaled treatment for her asthma and a high dose of oral corticosteroids for ABPA. Her symptoms improved but during the decrease of corticosteroids, the patient presented a relapse. She received itraconazole in addition to corticosteroids. Four months later, she presented a drug-induced hepatitis due to itraconazole which was immediately stopped. During the monitoring of her asthma which was partially controlled, the patient presented an aseptic osteonecrosis of both femoral heads that required surgery. Nine months after itraconazole discontinuation, she presented a second relapse of her ABPA. She received voriconazole for nine months associated with a low dose of systemic corticosteroid therapy with an improvement of her symptoms. After discontinuation of antifungal treatment, there was no relapse for one year follow-up

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Probing the crucial role of Leu31 and Thr33 of the Bacillus pumilus CBS alkaline protease in substrate recognition and enzymatic depilation of animal hide.

The sapB gene, encoding Bacillus pumilus CBS protease, and seven mutated genes (sapB-L31I, sapB-T33S, sapB-N99Y, sapB-L31I/T33S, sapB-L31I/N99Y, sapB-T33S/N99Y, and sapB-L31I/T33S/N99Y) were overexpressed in protease-deficient Bacillus subtilis DB430 and purified to homogeneity. SAPB-N99Y and rSAPB displayed the highest levels of keratinolytic activity, hydrolysis efficiency, and enzymatic depilation. Interestingly, and at the semi-industrial scale, rSAPB efficiently removed the hair of goat hides within a short time interval of 8 h, thus offering a promising opportunity for the attainment of a lime and sulphide-free depilation process. The efficacy of the process was supported by submitting depilated pelts and dyed crusts to scanning electron microscopic analysis, and the results showed well opened fibre bundles and no apparent damage to the collagen layer. The findings also revealed better physico-chemical properties and less effluent loads, which further confirmed the potential candidacy of the rSAPB enzyme for application in the leather industry to attain an ecofriendly process of animal hide depilation. More interestingly, the findings on the substrate specificity and kinetic properties of the enzyme using the synthetic peptide para-nitroanilide revealed strong preferences for an aliphatic amino-acid (valine) at position P1 for keratinases and an aromatic amino-acid (phenylalanine) at positions P1/P4 for subtilisins. Molecular modeling suggested the potential involvement of a Leu31 residue in a network of hydrophobic interactions, which could have shaped the S4 substrate binding site. The latter could be enlarged by mutating L31I, fitting more easily in position P4 than a phenylalanine residue. The molecular modeling of SAPB-T33S showed a potential S2 subside widening by a T33S mutation, thus suggesting its importance in substrate specificity

Hydrolysis curves of keratin treated with purified SAPB enzymes.

<p>The purified proteases used were: rSAPB, SAPB-L31I, SAPB-T33S, SAPB-N99Y, SAPB-L31I/T33S, SAPB-L31I/N99Y, SAPB-T33S/N99Y, and SAPB-L31I/T33S/N99Y. Each point represents the mean (n  = 3) ± standard deviation.</p

Depilation activities of SAPB enzymes on animal hides and a scanning electron micrograph-selected sectional view.

<p>SAPB enzymes were incubated for 8 h at 37°C with goat skin (A), rabbit hair (B), cow hide (C), and sheep wool (D). Every test was carried out with a control without adding enzyme. Magnification and micrographs of 61× (E), 217× (F), and 435× (G) were taken following the treatment of goat skin with rSAPB enzyme-assisted depilation. Samples show a clean pore, indicating complete removal of the hair and root.</p

Specific activities and keratin/casein ratios of the purified wild-type and mutant SAPB enzymes using keratin and casein as substrates.

a<p>Specific activity is defined as units (U) of activity per amount (mg) of protein. 1 U of protease activity was defined as the amount of enzyme that liberated 1 µg tyrosine per min under the optimal temperature and pH values of the respective recombinant enzymes using keratin or casein as a substrate. Proteins were estimated by the Bradford method using the Dc protein assay kit obtained from Bio-Rad Laboratories (Inc., Hercules, CA, USA).</p>b<p>The experiments were conducted three times and ± standard errors are reported.</p>c<p>The relative activity is calculated by taking the specific activity of the wild-type as 1.00.</p><p>Specific activities and keratin/casein ratios of the purified wild-type and mutant SAPB enzymes using keratin and casein as substrates.</p

Kinetic parameters of the purified wild-type and mutant SAPB enzymes with selected synthetic peptide substrates.

<p>Assays were performed using the purified proteases in 100 mM buffer containing 2 mM Ca²⁺, and 0.2 mM to 50 mM synthetic peptide substrates (YLV and FAAF) at suitable pH. The samples were incubated for 10 min at suitable temperature. Results are mean values from triplicate experiments. 1 U of protease activity was defined as the amount of enzyme that catalyses the transformation of 1 mM pNA per minute under standard assay conditions.</p><p>Kinetic parameters of the purified wild-type and mutant SAPB enzymes with selected synthetic peptide substrates.</p

Structural interpretation.

<p>(A) SAPB model showing the positions of the mutated amino-acids. (B) Surface representation of SAPB which the YLV tripeptide synthetic substrate, shown in orange sticks, has docked. Close up views of (C) the catalytic cavity and Leu31, showing a superposition of surface and ribbon representations of the SAPB model, (D) the catalytic cavity and the Ile31 residue in the SAPB-L31I model. (E) Thr33 in the SAPB model showing a superposition of surface and ribbon representations, and (F) Ser33 in the SAPB-T33S model showing a superposition of surface and ribbon representations. (G) Asn99 in the SAPB model showing a superposition of surface and ribbon representations, and (H) Tyr99 in the SAPB-N99Y model showing a superposition of surface and ribbon representations. The mutated residues are shown in yellow sticks and surfaces. These figures were prepared using the PyMol software (<a href="http://www.pymol.org" target="_blank">http://www.pymol.org</a>).</p

Substrate specificities of the wild-type and mutant SAPB enzymes with proteins and synthetic peptides as substrates.

a<p>Values represent means of three replicates, and ± standard errors are reported.</p>b<p>The unit activity of each substrate was determined by measuring absorbance at specified wavelengths as described in Section 2.</p><p>Substrate specificities of the wild-type and mutant SAPB enzymes with proteins and synthetic peptides as substrates.</p

Analysis of pollution parameters from the effluent of depilating processes of goat skins.

<p>Results were average of three different sets of experiments.</p><p>Analysis of pollution parameters from the effluent of depilating processes of goat skins.</p