Estimation of the introduction risk of non-indigenous species through ship ballast water in the Port of Douala (Cameroon).

The transport of non-indigenous species in ship's ballast water represents a threat to marine biodiversity. This study is the first on marine bioinvasion in Sub-Saharan Africa. The Port of Douala (PoD), located in the Gulf of Guinea, is experiencing increasing maritime traffic, hence the importance of preventing biological invasions. PoD received ballast water from 41 ports and 20 ecoregions during the study period (2018-2021). We used a biological invasion model and showed that ships from the ports of Antwerp, Durban, Dar es Salaam, Pointe-Noire (Southern Gulf of Guinea) and Dakar (Sahelian Upwelling), with their associated ecoregions present a major invasion risk. Treating ballast water from these ships to IMO D-2 standards could reduce their probability of biological invasion by 97.18, 98.43, 98.80, 98.77 and 98.84 %, respectively. Climate change may also mitigate the risk of biological invasion, particularly for ships in the North Sea ecoregion from the port of Antwerp.

Functional diversity of the fish fauna in the Nyong estuary (Atlantic Coast, Cameroon), and its correlation with environmental variables.

Archaic fishing, anthropogenic pollution linked to demographic and economic growth stand to be a real threat to the richness and abundance of the aquatic fauna of estuaries in Sub-Saharan Africa. The knowledge of the Nyong estuary ichthyofauna's ecology in Cameroon is particularly essential to establish a management plan and sustainable management of this important ecosystem. The Nyong estuary ichthyofauna was composed of 13 families, 20 genera and 22 species, from February to June 2020. Eleven species had a marine affinity while11 others were from the freshwater dirivation. Mormyridae (14%), Cichlidae (14%) and Clupeidae (14%) were the most represented families. Also, Chrysichthys nyongensis was the most abundant species with a frequency of 30.26%. Despite the low diversity in the study area, the specific diversity index showed that Dikobe was the most diverse station (H' = 2.98 and J = 0.46), contrary to Donenda's station (H' = 2.30 and J = 0.22). In general, significant correlations were noted between physico-chemical parameters and the total abundances of the different fish species (P < 0.05). Thus, in Behondo, characterized by polyhaline waters, Gnathonemus petersii in contrary Pellonula vorax was positively and significantly correlated with salinity, electrical conductivity and total dissolved solids. This study clearly illustrates that the distribution of ichthyofauna in the Nyong estuary mainly depends on the environmental variables. The data obtained would therefore allow the implementation of a sustainable fisheries development and management plan in the localities concerned by this study, and sensitize fishermen on the need to respect the fishing code.

Four new species of Hysterocinetida (Protozoa: Ciliophora) from the digestive tract of earthworms collected to the lower Nyong estuary (South Coast, Cameroon).

Hysterocinetida are a large assemblage of ciliates characterized by sucker and buccal apparatus. They have a wide distribution in the digestive tract of oligochaete annelids of the genus Alma that inhabit hydromorphic parts of non-anthropic hydrosystems. On the basis of morphological, morphometric and infraciliature characteristics revealed by ammoniacal silver carbonate and 4',6-Diamidino-2-Phenyl Indole (DAPI) staining techniques, four forms were identified as new members belonging to three genera: Preptychostomum, Proptychostomum and Thurstonia. Preptychostomum donendaensis n. sp. is ovoid with a slightly narrowed anterior part and is commensal to the digestive tract of Alma emini and A. nilotica. There are 20-23 kineties on the lower side and 42-45 on the upper side. Proptychostomum gigas n. sp. is pear-shaped, with a narrowed anterior part and a wide posterior part (125-138 µm × 80-85 µm). There are 40 to 44 kineties, equally distributed on both sides of the ciliate. Its sucker is circular and measures 31-34 µm in diameter. The peristome follows the contour of the cell and the infundibulum has a turn of spire. Thurstonia emini n. sp. is identified in the digestive tract of A. emini. The cell is elongate, with the anterior pole narrower than the truncate posterior pole (90-115 µm × 40-55 µm). The kineties are equally distributed on both sides of the ciliate. The sucker is in the shape of an inverted U. Thurtonia nilotica n. sp. is commensal of the digestive tract of A. nilotica. The cell is pear-shaped, with the anterior part narrowed and the posterior part swollen (110-114 µm × 85-92 µm). 46 to 50 kineties are unevenly distributed on both sides of the ciliate. The sucker is shaped like an inverted lunar crescent.

A prospective study on the pathogenesis of catheter-associated bacteriuria in critically ill patients.

BACKGROUND: Updating the pathogenesis of catheter-associated bacteriuria (CA-bacteriuria) in the intensive care unit (ICU) is needed to adapt prevention strategies. Our aim was to determine whether the main pathway of CA-bacteriuria in ICU patients was endoluminal or exoluminal. In a prospective study, quantitative urine cultures were sampled from catheter sampling sites, collector bags and the catheter outer surface near the meatus from days 1 to 15 after catheterization. The endoluminal pathway was CA-bacteriuria (defined as 102 CFU/mL) first in collector bags and then in catheters. The exoluminal pathway was CA-bacteriuria first in catheters, on day 1 in early cases and after day 1 in late cases. RESULTS: Of 64 included patients, 20 had CA-bacteriuria. Means of catheterization days and incidence density were 6.81 days and 55.2/1000 catheter-days. Of 26 microorganisms identified, 12 (46.2%) were Gram positive cocci, 8 (30.8%) Gram negative bacilli and 6 yeasts. Three (11.5%) CA-bacteriuria were endoluminal and 23 (88.5%) exoluminal, of which 10 (38.5%) were early and 13 (50%) late. Molecular comparison confirmed culture findings. A quality audit showed good compliance with guidelines. CONCLUSION: The exoluminal pathway of CA-bacteriuria in ICU patients predominated and surprisingly occurred early despite good implementation of guidelines. This finding should be considered in guidelines for prevention of CA-bacteriuria.

Evaluation of the health risks linked to two swimming pools regularly frequented from the city of Yaounde in Cameroon (Central Africa).

The study highlights the presence of pathogenic strains of microorganisms in two swimming pools, highly frequented in the city of Yaounde. Thus, the water samples from these swimming pools have undergone physicochemical and biological treatments using conventional techniques. Three groups of microorganisms (Bacteria, Protozoa, and Helminths) were identified and quantified in these swimming pools with weakly acidic waters (6.79 ± 0.35) with an average temperature of 26.63 ± 0.53 °C and suspended matter ranging from 2 to 150 mg.l-1. The total bacterial load varies between 8 × 103 and 6000 × 103 CFU/100 ml. It consists of mesophilic aerobic heterotrophic bacteria, fecal coliforms, total coliforms, fecal streptococci, Staphylococcus aureus, and Pseudomonas aeruginosa. Protozoan cysts and oocysts range from 122 to 505 per liter of water. These values are slightly lower for helminth eggs and larvae (0 to 108 eggs and larvae/l). In both swimming pools, significant correlations were observed between some abiotic and biotic parameters. The waters of the studied swimming pools are subject to fecal pollution. Swimmers would therefore be exposed to biological contaminations, responsible for pathologies. The most common diseases are linked to gastroenteritis (diarrhea), but infections of all kinds may be overgrown (conjunctivitis, ear infections, dermatitis, respiratory infections).

Morphology and infraciliature of two new earthworm ciliates, Hoplitophrya polymorphus sp. nov. and Anoplophrya simplex sp. nov. (Ciliophora: Oligohymenophorea: Astomatia).

Morphological and infraciliature studies carried out using pyridinated ammoniacal silver carbonate and the 4',6-diamidino-2-phenylindole (DAPI) staining techniques, led to the identification of two new species of ciliates pertaining to the subclass Astomatia. The first species, Hoplitophrya polymorphus sp. nov., displays two main cellular forms: the elongated form (150-247 µm long and 40-87 µm width) and the stocky form (140-170 µm long and 70-98 µm width). The macronucleus is generally skinny in the elongated forms and ribbon-shaped in the stocky forms. The common feature of the two cellular shapes uniting them in the same species is the identical structure of their skeletal apparatus, a V-shaped element located in an apical depression and bearing skeletal fibres on its ventral face. The second species, Anoplophrya simplex sp. nov., is totally deprived of skeletal apparatus. The cell shape is fusiform and dorsoventrally flattened (105-180 µm long and 65-125 µm width). Six to 12 pulsatile vacuoles form two rows arranged symmetrically on either side of the macronucleus. These two newly identified species highlight the extremely rich diversity of ciliates inhabiting the digestive tract of tropical earthworms.