SARS-CoV-2-Neutralizing Antibody Response and Correlation of Two Serological Assays with Microneutralization.

SARS-CoV-2 has caused a huge pandemic affecting millions of people and resulting innumerous deaths. A better understanding of the correlation between binding antibodies and neutralizing antibodies is necessary to address protective immunity post-infection or vaccination. Here, we investigate the humoral immune response and the seroprevalence of neutralizing antibodies following vaccination with adenovirus-based vector in 177 serum samples. A Microneutralization (MN) assay was used as a reference method to assess whether neutralizing antibody titers correlated with a positive signal in two commercially available serological tests:a rapid lateral flow immune-chromatographic assay (LFIA) and an enzyme-linked Fluorescence Assay (ELFA). Neutralizing antibodies were detected in most serum samples (84%). COVID-19 convalescent individuals showed high antibody titers and significant neutralizing activity. Spearman correlation coefficients between the serological and neutralization results ranged from 0.8 to 0.9, suggesting a moderate to strong correlation between commercial immunoassays test results (LFIA and ELFA) and virus neutralization.

Moroccan Experience of Targeted Screening for Inborn Errors of Metabolism by Tandem Mass Spectrometry.

BACKGROUND: Expanded newborn screening using tandem mass spectrometry (MS/MS) for inborn errors of metabolism (IEM), such as organic acidemias (OAs), fatty acid oxidation disorders (FAODs), and amino acid disorders (AAs), is increasingly popular but has not yet been introduced in Africa. With this study, we aim to establish the disease spectrum and frequency of inborn errors of OAs, FAODs, and AAs in Morocco. METHODS: Selective screening was performed among infants and children suspected to be affected with IEM between 2016 and 2021. Amino acids and acylcarnitines spotted on filter paper were analyzed using MS/MS. RESULTS: Out of 1178 patients with a clinical suspicion, 137 (11.62%) were diagnosed with IEM, of which 121 (88.3%) patients suffered from amino acids disorders, 11 (8%) were affected by FAOD, and 5 (3.7%) by an OA. CONCLUSIONS: This study shows that various types of IEM are also present in Morocco. Furthermore, MS/MS is an indispensable tool for early diagnosis and management of this group of disorders.

Isolation and Characterization of Phosphate Solubilizing Streptomyces sp. Endemic from Sugar Beet Fields of the Beni-Mellal Region in Morocco.

In the course of our research, aimed at improving sugar beets phosphorus nutrition, we isolated and characterized Streptomyces sp. strains, endemic from sugar beet fields of the Beni-Mellal region, which are able to use natural rock phosphate (RP) and tricalcium phosphate (TCP) as sole phosphate sources. Ten Streptomyces sp. isolates yielded a comparable biomass in the presence of these two insoluble phosphate sources, indicating that they were able to extract similar amount of phosphorus (P) from the latter for their own growth. Interestingly, five strains released soluble P in large excess from TCP in their culture broth whereas only two strains, BP, related to Streptomyces bellus and BYC, related to Streptomyces enissocaesilis, released a higher or similar amount of soluble P from RP than from TCP, respectively. This indicated that the rate of P released from these insoluble phosphate sources exceeded its consumption rate for bacterial growth and that most strains solubilized TCP more efficiently than RP. Preliminary results suggested that the solubilization process of BYC, the most efficient RP and TCP solubilizing strain, involves both acidification of the medium and excretion of siderophores. Actinomycete strains possessing such interesting RP solubilizing abilities may constitute a novel kind of fertilizers beneficial for plant nutrition and more environmentally friendly than chemical fertilizers in current use.

Complete Genome Sequence of a 2019 Novel Coronavirus (SARS-CoV-2) Strain Causing a COVID-19 Case in Morocco.

Here, we report a complete genome sequence obtained for a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strain isolated from a nasopharyngeal swab specimen of a Moroccan patient with coronavirus disease 2019 (COVID-19).

Assessment of Chemical Risks in Moroccan Medical Biology Laboratories in Accordance with the CLP Regulation.

BACKGROUND: Medical laboratory workers are frequently exposed to a wide range of chemicals. This exposure can have adverse effects on their health. Furthermore, a knowledge lack of the chemical risk increases the likelihood of exposure. The chemical risk assessment reduces the risk of exposure to hazardous chemicals and therefore, guarantees health and safety of the workers. METHOD: The chemical risk assessment was conducted using a modified INRS method, according to the new CLP Regulation, of 11 unit laboratories in a Moroccan medical laboratory. Observation of each workstation and analysis of safety data sheets are key tools in this study. RESULTS: A total of 144 substances and reagents that could affect the health of the analytical technicians were identified. Among these products, 17% are concerned by the low priority risk score, with 55% concerned by the average priority risk score and 28% concerned by the high priority risk score. This study also enabled to better identify the chemical agents that have restrictive occupational exposure limit value and controls were conducted to this effect. On the basis of the results obtained, several corrective and preventive measures have been proposed and implemented. CONCLUSION: Risk assessment is essential to ensure the health and safety of workers and to meet regulatory requirements. It enables to identify all the risky manipulations and to adopt appropriate preventive measures. However, it is not a one-time activity but it must be continuous in order to master the changes and thus ensure the best safety of all.

Single-Molecule Sequencing (PacBio) of the Staphylococcus capitis NRCS-A Clone Reveals the Basis of Multidrug Resistance and Adaptation to the Neonatal Intensive Care Unit Environment.

The multi-resistant Staphylococcus capitis clone NRCS-A has recently been described as a major pathogen causing nosocomial, late-onset sepsis (LOS) in preterm neonates worldwide. NRCS-A representatives exhibit an atypical antibiotic resistance profile. Here, the complete closed genome (chromosomal and plasmid sequences) of NRCS-A prototype strain CR01 and the draft genomes of three other clinical NRCS-A strains from Australia, Belgium and the United Kingdom are annotated and compared to available non-NRCS-A S. capitis genomes. Our goal was to delineate the uniqueness of the NRCS-A clone with respect to antibiotic resistance, virulence factors and mobile genetic elements. We identified 6 antimicrobial resistance genes, all carried by mobile genetic elements. Previously described virulence genes present in the NRCS-A genomes are shared with the six non-NRCS-A S. capitis genomes. Overall, 63 genes are specific to the NRCS-A lineage, including 28 genes located in the methicillin-resistance cassette SCCmec. Among the 35 remaining genes, 25 are of unknown function, and 9 correspond to an additional type I restriction modification system (n = 3), a cytosine methylation operon (n = 2), and a cluster of genes related to the biosynthesis of teichoic acids (n = 4). Interestingly, a tenth gene corresponds to a resistance determinant for nisin (nsr gene), a bacteriocin secreted by potential NRCS-A strain niche competitors in the gut microbiota. The genomic characteristics presented here emphasize the contribution of mobile genetic elements to the emergence of multidrug resistance in the S. capitis NRCS-A clone. No NRCS-A-specific known virulence determinant was detected, which does not support a role for virulence as a driving force of NRCS-A emergence in NICUs worldwide. However, the presence of a nisin resistance determinant on the NRCS-A chromosome, but not in other S. capitis strains and most coagulase-negative representatives, might confer a competitive advantage to NRCS-A strains during the early steps of gut colonization in neonates. This suggests that the striking adaptation of NRCS-A to the NICU environment might be related to its specific antimicrobial resistance and also to a possible enhanced ability to challenge competing bacteria in its ecological niche.

Assessment of iron deficiency in the context of the obesity epidemic: importance of correcting serum ferritin concentrations for inflammation.

BACKGROUND: The correction of serum ferritin (SF) concentrations for inflammation because of infectious or parasitic diseases was recently proposed, especially in developing countries, but in many countries, adiposity has become the main cause of inflammation. OBJECTIVE: We assessed, overall and by adiposity status, the bias in the estimation of iron deficiency (ID) on the basis of uncorrected SF. DESIGN: A cross-sectional survey in 2010 in Rabat-Salé, Morocco, used a random sample of 811 women aged 20-49 y. Adiposity was assessed by body mass index (BMI) (in kg/m²) (normal: BMI <25; overweight: BMI ≥25 to <30; obese: BMI ≥30), waist circumference, and body fat. Inflammation was indicated by a C-reactive protein (CRP) concentration >2 mg/L. ID was indicated by an SF concentration <15 µg/L. The correction factor of SF for inflammation was derived from our sample. Differential effects of SF correction on ID status on the basis of adiposity were assessed by models that included adiposity × correction interactions and accounted for the within-subject correlation. RESULTS: The prevalence of overweight was 33.0% and of obesity was 34.0%. Inflammation (42.3%) was strongly linked with adiposity (20.1%, 37.6%, and 68.4% in normal, overweight, and obese subjects, respectively; P < 0.0001). SF increased from a CRP concentration >2 mg/L. The correction factor of SF was 0.65. The prevalence of ID (37.2% compared with 45.2%; difference -8.0%, P < 0.0001) was underestimated by not correcting SF, and the difference increased with adiposity (-2.9%, -8.5%, and -12.4% in normal, overweight, and obese subjects, respectively; P-interaction < 0.0001). Analogous results were observed for other adiposity measures. CONCLUSION: In developing countries where ID remains prevalent but rates of obesity are already high, corrected SF should be used when assessing ID status, even if infectious or parasitic diseases are no longer widespread. This trial was registered at clinicaltrials.gov as NCT01844349.

High prevalence of hypovitaminosis D in Morocco: relationship to lifestyle, physical performance, bone markers, and bone mineral density.

OBJECTIVES: We undertook this study to determine the prevalence of hypovitaminosis D, its determinants, and its relationships to physical performance, serum parathyroid hormone (PTH) concentration, bone mineral density, and biochemical markers of bone turnover in healthy, ambulatory, pre- and postmenopausal women. METHODS: The group studied included 415 women aged 24 to 77 years. Between July and September, we assessed calcium intake and measured serum calcium, phosphorus, albumin, alkaline phosphate, 25-hydroxyvitamin D (25(OH)D), PTH, osteocalcin, and C-terminal cross-linking telopeptide of Type I collagen. We also measured bone mineral density (BMD) by dual-energy radiograph absorptiometry in the spine and total femur. Three tests were used to assess physical performance: timed get-up-and-go test, 5-times-sit-to-stand test, and 2.4 m speed walk. RESULTS: The prevalence of vitamin D insufficiency (<30 ng/mL) was 91%. In multiple logistic regression, the main determinants of hypovitaminosis D were age >55 years (OR 2.14 [95% IC, 1.1-4.1; P = 0.026)], wearing a veil [OR 2 (95% IC, 1.1-4; P = 0.04)], time spent outdoors less than 30 min/d [OR 2.8 (95% IC: 1.4-5.7; P = 0.003)], and daily calcium intake less than 700 mg [OR 2.39 (95% IC, 1.2-4.7; P < 0.01)]. A significant inverse correlation between 25 OH and osteocalcin (r = -0,18, P < 0001), 25 OH, and Type I collagen (r = -0,15, P = 0003) were observed. By Locally Weighted Regression and Scatterplot Smoothing technique, there was an increase in PTH level when S-25(OH)D was below 30 ng/mL. After adjustment for age, both spine BMD and total femoral BMD failed to show any significant correlation with serum 25(OH)D and PTH. There was no correlation between any physical performance tests and 25(OH)D levels. CONCLUSIONS: Our study showed that during the summer season, vitamin D insufficiency is very common in healthy adult Moroccan women. Lack of sun exposure and veiled clothing style were the most important factors that influenced hypovitaminosis D. Patients with hypovitaminosis D had a high bone turnover, whereas there was no effect on BMD and physical performance. Further research is needed to evaluate the clinical impact of the above findings.