Prevalence, Resistance to Quinolones/Fluoroquinolones of <i>Staphylococcus aureus</i>Strains Isolated in the Hospital and University Center of Brazzaville, Republic of Congo

Staphylococcus aureus is a gram-positive pathogenic bacterium responsible for various infections including skin suppurations. Quinolones are sometimes used last in infections. The Staphylococcus aureus objective of this study was to determine the prevalence and assess the level of resistance to quinolones of Staphylococcus aureus trains isolated in the Hospital and University Center of Brazzaville (CHU-B). 40 strains of Staphylococcus aureus from various biological products were isolated and identified by bacteriological methods. The study of the resistance of these different strains to antibiotics (Quinolones/Fluoroquinolones) was carried out by the phenotypic method, by antibiogram. A total of 40 Staphylococcus aureus strains were isolated including 13 (32.50%) community strains, 27 (67.5%) clinical strains distributed as follows: neonatal and pediatric service 29.62% and 25.92%, surgery 18.51%, contagious 14.81%, emergencies 7.4% and delivery block 3.7%. 60% of strains were isolated in women and 40% in men. The average age of those infected was 16 years and older. 90% strains were resistant to Nalidixic acid (AN), 72.5% to Ofloxacin (OFL), 67.5% to Ciprofloxacin (CIP), 70% to Norfloxacin (NOR), 62.5% to Levofloxacin (LEV), 47.5% to Moxifloxacin (MXF), and 40% strains were resistant to all antibiotics tested.

Prevalence of Virological Markers HIV, HBV and HCV in Homozygous Sickle Cell Patients at Brazzaville University Hospital

In order to evaluate the seroprevalence of major viral markers, a descriptive study was carried out in homozygous sickle cell transfusion patients at the University Hospital of Brazzaville. The profiles were determined in 51 patients, 32 of whom were male and 19 female, with an age range of 17 to 51 years, admitted to the clinical hematology department of the University Hospital and to the National Reference Center for Sickle Cell Disease. The tests were performed on pre- and post-transfusion blood samples. The following reagents were used: GeenscreenTMultraHIVAg-Ab, MonolisaAg-HBs plus, MonolisaHCV Ag-Ab Ultrade Bio-Radot for the detection of HIV, HBV and HCV by fourth generation ELISA tests (serological tests). The results showed that the indications for blood transfusion were: acute crises of anemia due to malaria and in some cases of Vaso-Occlusive Crises (VOC) resistance to analgesic treatment. The prevalence rates of the markers before the new transfusion were respectively: HIV: 0%, HBV: 1.96%, HCV: 3.92%. After transfusion, the final seroprevalence rates of the markers are: HIV: 0%, HBV: 5.88%, HCV: 3.92%. The seroconversion rate for HBV was 3.92%. One case of HBV + HCV co-infection (1.96%). Conclusion: Transfusion safety is achieved through good transfusion practices and the qualification of blood donations. Homozygous sickle cell disease, characterized by frequent anemia attacks, requires a guarantee of efficient transfusion practices in order to limit microbial risks.

Mortality from Stroke in Young People in Brazzaville

Introduction: Cerebrovascular accidents (CVA) are an absolute neurovascular emergency and the main cause of mortality and acquired disability in adults. In the Congo, stroke is the leading cause of mortality and the leading cardiovascular emergency, with a hospital frequency of between 49.74% and 56.2%. The aim of the study was to identify the mortality factors associated with stroke in young people in Brazzaville. Patients and Methods: This is a longitudinal analytical study conducted from February to period from February to September 2019 in the neurology, general intensive care and medical emergency departments of the Brazzaville University Hospital (CHUB). All subjects aged 18 - 55 years of completed age, admitted for arterial stroke confirmed by brain imaging, were included. Study variables were: age, gender, socioeconomic level, laterality, time to admission and CT scan, vascular risk factors, history of cardiomyopathy, atrial fibrillation, TIA (transient ischemic attack) or stroke, NIHSS (National Institutes of Health Stroke Scale) score, Glasgow score, blood pressure, temperature, heart rate, occurrence or non-occurrence of complications, blood glucose, creatinine, lipid profile and blood count. Data were analyzed using SPSS 21 software. Descriptive analyses were performed using SPSS 21 software. Results: 103 patients were included in the study, of whom 45 (43.7%) had ischemic stroke and 58 (56.3%) with hemorrhagic stroke. Mortality was high at 29.1% in our study, and mainly concerned hemorrhagic strokes (73.7%). Two-week mortality in our study accounted for 63.33% of total lethality. After simple logistic regression, the factors associated with death within two weeks were age between 40 - 44 years (OR (odds ratio) = 2.95;p = 0.01), hemorrhagic stroke (OR = 1.41;p = 0.07), mass effect (OR = 3.26;p < 0.01), ventricular flooding (OR = 2.86;p < 0.001), Glasgow score (OR = 2.95 (0.92 - 9.43);p = 0.06), NIHSS score on admission > 15 (OR = 5.89 (2.90 - 11.95);p < 0.001) and bronchopulmonary infection (OR = 30, 95 (4.04 - 236.88), p < 0.001). From multivariate logistic regression, only NIHSS score on admission > 15 emerged as a predictor of death within two weeks (OR = 5.89 (2.90 - 11.95);p Conclusion: This study confirms the basic data of the African literature concerning stroke, as several factors were identified as independent factors associated with mortality.

Antibiotic Resistance Profile of Enterococcus faecalis and Enterococcus faecium Isolates from Urine and Pleural Fluid in Two Hospitals of Cameroon

Enterococcus faecalis and Enterococcus faecium rank among the leading causes of nosocomial bacteremia and urinary tract infections. They often persist on hospital surfaces due to their ability to withstand adverse environmental conditions (low or high temperatures, high pH, and high salinity). The global Enterococcus faecalis-Enterococcus faecium ratio is currently shifting towards Enterococcus faecium. Enterococci present variable levels of resistance to certain families of antibiotics. This is the case for aminoglycosides, beta-lactams and cephalosporins. In 2017, WHO ranked Enterococci among priority pathogens for research and development of new antibiotics. The objective of our study was to determine the antibiotic resistance profile of Enterococcus faecalis and Enterococcus faecium isolates from urine and pleural fluid in two hospitals in Cameroon. This cross-sectional and analytic study was carried out between June to August 2023 on hospitalized and day patients in which a cytobacteriological test of urine and pleural fluid was done. The samples were inoculated on CLED Agar for urine and on Chocolate + polyvitex and blood agar (prepared from Columbia agar) for pleural fluid samples and incubated at 37℃ for 18 to 24 hours. Identification of isolates was carried out using the API 20 STREP micro gallery (Biomerieux, France) and tested for antimicrobial susceptibility. The data on socio-demographical and potential risk factors were recorded using self-administered questionnaires and data from laboratory analyses of the specimen were collected in a data capture sheet. Potential risk factors associated with the presence of Enterococci, were evaluated using the logistic regression in univariate and multivariate analysis. P value < 0.05 was considered as significant. A total of 511 patients were recruited who were predominantly females. Enterococcus spp were isolated in 27.79% of our samples with Enterococcus faecalis mostly encountered. Enterococcus spp showed a high level of resistance to penicilline (99.3% to Ampicilline), macrolides (66.2% to Erythromycin) and cyclines (85.2% to Doxycycline). Hospitalisation, access to health facilities, contact with urine specimen and hand hygiene practices were risk factors related to infection with Enterococcus spp while hospitalisation, health facility and hand hygiene were related to glycopeptide resistant Enterococcus. Strict compliance with hygiene rules and appropriate antibiotic consumption could help in the fight against these infections.

Coordination of Regulation Devices for Damping Power Oscillations in a Dynamic Disturbance Context: A Fuzzy Logic-Based Approach Applied to the Electrical Grid of the Republic of Congo

This article presents a fuzzy logic-based approach to coordinate the control devices of the power system, such as Power System Stabilizers (PSS) and Static Synchronous Compensators (STATCOM), to damp power oscillations caused by dynamic disturbances. At first, we used the Lyapunov method to study the dynamic stability of the power grid in the Republic of Congo. This method allowed us to analyze the eigenvalues of the state variable matrix and highlight the eigenvalues in the complex plane. Secondly, we proposed a fuzzy logic-based controller to account for uncertainties existing near the thresholds. The inputs to this controller are the generator speed and generator rotor angle. We demonstrated the effectiveness and feasibility of this fuzzy control by applying it to the power grid of the Republic of Congo, with three power stabilizers and two STATCOMs. .

Direct shear tests on cemented paste backfill-rock wall and cemented paste backfill-backfill interfaces

Even though a large number of large-scale arch dams with height larger than 200 m have been built in the world, the transient groundwater flow behaviors and the seepage control effects in the dam foundations under difficult geological conditions are rarely reported. This paper presents a case study on the transient groundwater flow behaviors in the rock foundation of Jinping I double-curvature arch dam, the world＇s highest dam of this type to date that has been completed. Taking into account the geological settings at the site, an inverse modeling technique utilizing the time series measurements of both hydraulic head and discharge was adopted to back-calculate the permeability of the foundation rocks,which effectively improves the uniqueness and reliability of the inverse modeling results. The transient seepage flow in the dam foundation during the reservoir impounding was then modeled with a parabolic variational inequality（PVI） method. The distribution of pore water pressure, the amount of leakage, and the performance of the seepage control system in the dam foundation during the entire impounding process were finally illustrated with the numerical results.

Illumination Level Effects on Macroscopic Parameters of a Bifacial Solar Cell

This study presents a method based on the experimental measurement of the short-circuit current (Icc) and the open circuit voltage (Vco) of the solar cell. It permits the determination of recombination parameters such as: diffusion length (L), back surface recombination velocity (Sb), intrinsic junction recombination velocity (Sjo), and macroscopic parameters in particular, the shunt and series resistances of a bifacial solar cell for various illumination levels (n). Illumination level effects on macroscopic parameters are highlighted.

Characterization and Evaluation of the Potential Uses of Mouyondzi Clay

The overall goal of this study is to characterize and to evaluate the potential uses of clay mined in the Nzaou locality. The Mou sample is argillaceous texture and medium plasticity (Ip = 28.9). Kaolinite is dominant clay species (44.41%). It is associated with illite (9%). Quartz and rutile are the main non clay minerals. The CEC is 8.66 cmol+/kg. Organic matter is low (0.839%). Total shrinkage obtained by dilatometry at 1200&degC is 9.26%. The chemical and mineralogical compositions have allowed using the ternary diagrams of Fabbri and Fiori that the MOU clay is favorable for glazed white stoneware (GWS) and for the production of clinker (KLK). Dondi typologies of ceramic tiles according to body color (mostly depending on the iron oxide content) and compactness (expressed by water absorption) have confirmed the use for the manufacture of the GWS and clinker. Classification always according to Dondi taking into account the rate of kaolinite, the fine fraction (&degC will be vitrified. Flexural strength at 1200&degC (16 MPa) does not correspond to the requirements of GWS or a clinker.

Stratigraphic Data and Groundwater Resources in the Coastal Sedimentary Basin of the Pointe-Noire Region (Republic of Congo)

The synthesis of geological and petroleum research undertaken in the coastal Sedimentary Basin of the Pointe-Noire region enabled the establishment of a lithostratigraphic scale. It has been observed that the order in which the series observed in outcrop and those encountered by deep wells succeed each other has allowed a value to be given to this relative scale. The study area corresponds to a longitudinal tectonic accident, fault or flexure. It belongs to the Cretaceous and Tertiary coastal sedimentary basin covered by the Plio-Pleistocene age formations (series of circuses), formed of highly permeable sands comprising multiple resistant horizons that store large bodies of water whose reserves are considered very important. Hydrographic network is composed of four main basins with a mediocre size. The quality of this groundwater is considered to be satisfactory for household consumption, but the sustainable management of these reserves requires constant checks on their quality as well as on the level of the reserves. All these resources put the agglomeration of Pointe-Noire close to large exploitable water reserves that meet the need for drinking water, even if, on the whole, the agglomeration is still experiencing many difficulties in terms of its drinking water supply.

Existence and Uniqueness of Solution for Cahn-Hilliard Hyperbolic Phase-Field System with Dirichlet Boundary Condition and Regular Potentials

Our aim in this paper is to study the existence and the uniqueness of the solutions for hyperbolic Cahn-Hilliard phase-field system, with initial conditions, Dirichlet boundary condition and regular potentials.

Poverty and Nutritional Health of the Child: Some Evidence from 2005 Demographic and Health Survey of Congo

The objective of this study is to identify the ways in which poverty could affect the nutritional health of the child and to analyze the strength of these links. On the whole, it appears that the relationship between poverty (measured by the wealth index) and health of the child (measured by an anthropometric index) is positive and highly significant.

Effect of Incorporation of Chips and Wood Dust Mahogany on Mechanical and Acoustic Behavior of Brick Clay

An experimental study was carried out on bricks using local materials in order to take into account the waste wood management to protect the environment and to reduce the cost of the habitat. Chips and sawdust were built-in clay bricks in order to study their influence on the compressive strength, Young’s modulus and the speed for soundproofing. Testings in compressive strength were made on the parallelepiped clay bricks, stabilized with different percentages of cement, with incorporation to various percentages of sawdust or wood chips (Mahogany), using a universal press. Young’s modulus was measured from the speed of sound by the ultrasonic method. The results obtained show that the incorporation of mahogany tree chips in the stabilized brick at 8% of cement, does not have much effect on the compressive strength. It was found that the incorporation of chips or sawdust on the clay brick, does not improve the compressive strength. The Young’s modulus decreases with increasing content of sawdust and practically remains constant regardless of the content of chips at 4% and 6% of cement. The clay brick mixed with 8% of mahogany sawdust can be an acoustic barrier.

Tree Biomass Estimation in Central African Forests Using Allometric Models

Quantifying the tropical forests’ carbon stocks is presently an important component in the implementation of the emerging carbon credit market mechanisms. This calls for appropriate allometric equations predicting biomass which currently are scarce. In this study, we aimed to estimate above- and below-ground biomass and carbon stocks of trees, and to identify the variation in diameter-height allometry of Ipendja mixed terra firme lowland tropical forest’s trees. The study area is located at Ipendja forest management unit (UFA), close to Dongou district (Likouala Department), in Northern Republic of Congo. This study combined forest inventory data of 1340 trees recorded from eight studied plots distributed in two sites, respectively Mokelimwaekili (i.e., Old-growth forest) and Sombo (i.e., Selective logging forest). Trees measurements were done with rectangular plots, each 25 × 200 m (i.e., 0.5 ha, 5000 m2). In eight studied plots (4 plots per site), only trees with DBH ≥ 10 cm were measured and identified. 1340 trees founded were belonged 145 species and 36 botanical families (n = 733 and n = 607, for Sombo and Mokelimwaekili respectively). The analyses were conducted using allometric method for aboveground biomass (AGB) and belowground biomass (BGB) estimations. The results showed that in Ipendja forest ecosystem the mean biomass is built up for AGB (346 Mg·ha-1) as well as for BGB (81.3 Mg·ha-1), with a significant difference between forest types (F = 23.46, df = 7.771, P = 0.001). It was obvious that biomasses in Mokelimwaekili (AGB: 559.7 Mg·ha-1, BGB: 131 Mg·ha-1) were higher than those of Sombo (AGB: 291.8 Mg·ha-1, BGB: 68.5 Mg·ha-1). By this study, Ipendja forest ecosystem has clearly variations on the diameter-height relationship and biomass across the plots and the sites.

Minimum and Maximum Temperature Trends in Congo-Brazzaville: 1932-2010

Maximum and minimum temperatures time series of Congo-Brazzaville are analyzed for trend and discontinuities over the period 1932 to 2010. Temperatures series show an irregular increase. A total of 8 synoptic stations show positive trends in their annual mean maximum temperature series, and 7 of them are significant, with higher trends for urban stations. Annual mean minimum temperature showed 6 stations having positive trends. This increase is in relation with observations at regional scale. However, the differences are observed between large towns (Brazzaville and Pointe-Noire), and small or rural towns (Dolisie, Sibiti, Impfondo, Djambala). Trends in diurnal temperature range (DTR) are large positive trends in maximum temperature that are mainly observed in cities. The curve of DTR shows a decreasing trend which indicates the increasing of minimum temperatures. The effects of urbanization on temperature trends are investigated. Most stations regarded as urban stations are still useful for trend analysis;being situated on the suburban of the studied cities, they are therefore, not substantially influenced by the urban heat island.

Stock and Flow of Carbon in Plant Woody Debris in Two Different Types of Natural Forests in Bateke Plateau, Central Africa

In order to know the role of plant woody debris in the carbon cycle, a study of carbon stocks and carbon flow of plant woody debris was conducted in the natural forests of the centre of the republic of Congo in the Bateke Plateau. Allometric equations were used to measure the carbon stock of in dead wood debris of Lesio-louna tropical rainforest. Three plots of 40 m × 40 m were delimited in each forest types. All plots were within 300 m of each other. The average stocks of carbon in coarse woody debris obtained are 10993 g·m-2 and 14172 g&#183m-2, respectively, in the Gallery forest (GF) and the hill-slope forest clump (HF), the difference of carbon stock between the two forests is not significant (p = 0.78). The interannual mean flow in both forests is respectively 1776 and 545 g·m-2&#183an-1 in the FG and the MSDS;this medium is not significant (p = 0.10). Carbon stocks of fine woody debris are respectively 965 and 83 g·m-2 in the GF and HF, difference is significant (p = 0.0013). The interannual mean flow of carbon in fine woody debris in the GF and the HF were respectively 310 g·m-2·an-1 and 51 g·m-2·an-1.

Application of the Adomian Decomposition Method (ADM) for Solving the Singular Fourth-Order Parabolic Partial Differential Equation

In this paper, the ADM method is used to construct the solution of the singular fourth-order partial differential equation.

Risk Factors of Early Neonatal Deaths in Pediatric Teaching Hospital in Bangui, Central African Republic

Background: The neonatal mortality rate in the Central African Republic (CAR) is 42.3 per 1000 live births in 2017, indicating that CAR is with the highest number of newborn deaths. Objective: The objective is to clarify the risk factors of neonatal deaths in this area. Methodology: A case-control study with retrospective data collection. Targets were newborns >7 days, hospitalized and dead (cases), and newborns admitted after the respective case during the study period and discharged before the 7th day of life. This study was carried out between 2016 and 2018 in the neonatal unit of the “Complexe Hospitalier Universitaire Pédiatrique de Bangui” (CHUPB), the only national hospital for newborns care in the CAR. Results: We included 902 newborns, with 451 cases of early neonatal death and 451 controls. 4168 newborns were admitted to the neonatology unit with 621 early death cases;a lethality rate of 14.9%. Early neonatal deaths factors were: newborns with low birth weight (OR = 22.59;95% CI [15.93 - 32.04]; P < 0.001);mothers who did not attend antenatal care (OR = 5.54;95% CI [3.95 - 7.79];P < 0.001), home delivery (OR = 0.70;95% CI [0.03 - 0.15];P < 0.001);young maternal age < 25 years (OR = 2.08;95% CI [1.58 - 2.73];P < 0.001);non-medical transport (OR = 2.14;95% CI [1.03 - 4.46];P = 0.03);origin from remote areas (OR = 5.25;95% CI [3.95 - 6.98];P < 0.001);isolated prematurity (P < 0.01);anoxo-ischemic encephalopathy (OR = 12.72;95% CI [6.54 - 34.73];P < 0.01);delivery by cesarean section (OR = 0.59;95% CI [0.41 - 0.84];P < 0.001);preterm delivery (OR = 29.36;95% CI [20.12 - 42.81];P < 0.001), and maternal lower education (OR = 5.65;95% CI [4.08 - 7.81];P < 0.001). Conclusion: The early neonatal mortality rate remains high in this area. Controlling the factors mentioned above might lead to improving the survival of newborns.

Petrology and Geodynamic Context of Metabasic Rocks of Nemba Complex in the West Congo Fold Belt (Republic of Congo)

The West Congo belt contains Paleoproterozoic and Neoproterozoic Units which are deformed during Panafrican event. The Neoproterozoic Unit contains rift and post rift deposits. The rift formation is made of metabasite, volcanic and volcano-sedimentary rocks. The metabasite constitutes the Nemba Complex which is considered put into place in a continental or oceanic context. Samples from Nemba Complex collected along the “Congo ocean railway realignment” are analyzed. Major elements indicate a low potassic subalkaline affinity of the samples. Classification diagrams based of major elements shows that the rocks are a tholeiitic serie constituted of andesitic basalts, sub-alkaline andesitic basalts and a sub-alkaline to alkaline basalts. Some samples with a calc-alkaline signature indicate a crustal contamination. The traces elements plots indicate that the rocks are the MORB. The spectrum of multi-elements is characteristic of continental rocks with a lithospheric origin. This is an agreement with many works on the Nemba Complex and the alkali plutons and acid volcanic rocks associated which attribute there a rift context.

Evaluation of Potential Extracts Antioxydant (Aqueous, Hydro-Ethanolic and Ethanolic) of an Aquatic Plant from the River Djoue (<i>Ledermanniella schlechteri</i>)

The aim for this present study was to evaluate the antioxidant potential of aqueous extracts (AE), hydro-ethanolic extracts (HE) and ethanolic extracts (EE) obtained from an aquatic plant (L. schlechteri) using a simple and fast method that is the CCM. This method revealed the presence of phenolics and flavonoids at different levels but with higher antioxidant activity in EE compared to AE. Among the two families of antioxidants evaluated, the phenolic compounds were found to be higher on the EE (5.85 mgEAG/MS) followed by the HE (5.06 mgEAG/MS) and less and less important on the AE (3.661 mgEAG/MS). While the less significantly elevated flavonoids showed values of 1.146 mgECa/MS for EE, 0.406 mgECa/MS for HE et 0.181 mgECa/MS for AE. However, the anti-free radical activity was also evaluated. Unlike the antioxidant activity, the ant-free radical activity with a greater IC50 was observed on AE with a rate of 66.66 mg/mL, then less on the hydro-ethanolic and ethanolic extracts, respectively at levels of 26.15 mg/mL et 19.18 mg/mL.

A Density Functional Theory Study of Methoxy and Atomic Hydrogen Chemisorption on Au(100) Surface

The adsorption of CH3O and H on the (100) facet of gold was studied using self-consistent periodic density functional theory (DFT-GGA) calculations. The best binding site, energy, and structural parameter, as well as the local density of states, of each species were determined. CH3O is predicted to strongly adsorb on the bridge and hollow sites, with the bridge site as preferred one, with one of the hydrogen atoms pointing toward a fourfold vacancy (bridge-H hollow). The top site was found to be unstable, the CH3O radical moving to the bridge –H top site during geometry optimization. Adsorption of H is unstable on the hollow site, the atom moving to the bridge site during geometry optimization. The 4-layer slab is predicted to be endothermic with respect to gaseous H2 and a clean Au surface.