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International audience; The present study aims to assess the temporal variations of some biotic and abiotic biodegradation parameters of 2 polymers (LDPE and PP) by the bacteria P. aeruginosa and S. aureus at acidic, neutral, and alkaline pH under mesophilic conditions. LDPE and PP fragments were immersed in the mineral solutions free of carbon sources containing P. aeruginosa or S. aureus cells. The initial pH values (pHi) of solutions were 5, 7 and 9. Incubation was carried out at 28°C for 10, 20, 30, 40, 50 and 60 days. Results showed that during incubations, the pH of the solutions varies over time. In most cases, the electrical conductivity and cell abundances increased. The weights of the polymers decreased. The cell abundance apparent increasing rates (CAAIR), the electrical conductivity apparent increasing rates (ECAIR), and the polymer weight apparent decreasing rates (PWADR) were estimated. The highest PWADR in the presence of LDPE was 0.4 mg/10days with P. aeruginosaat pHi 5 and 7, and 0.6 mg/10days with S. aureus under pHi 7. For PP, it was constant (0.7 mg/10days) under all pHi with S. aureus, but decreased in the presence of P. aeruginosa with increasing in pHi solutions. The ECAIR with LDPE decreased with increasing pHi with both bacterial species.The highest ECAIR of PP was recorded under pHi 5 with S. aureus and under pHi 7 with P. aeruginosa.The highest CAAIR with LDPE was 185.18 CFU/10days for P. aeruginosa at pHi 5 and 116.79 CFU/10days for S. aureus at pHi 7. With PP, it was 297.61 CFU/10days for P. aeruginosa at pHi 5 and 67.64 CFU/10days for S. aureusat pHi 7. The biodegradation parameters values recorded with of P. aeruginosa differed significantly (P

International audience; Species of the genus Proteus are the cause of several infections and represent one of the microorganisms commonly involved in hospital infections. These infections are sometime difficult to treat because the antibiotic resistance phenomenon, which represents one of the greatest health challenges today. This study aimed at comparing the diversity, abundance and antimicrobial susceptibility of Proteus species isolated from hospital wastewater and Mfoundi River in Yaounde (Cameroon, Central Africa). The physicochemical parameters were measured using appropriate techniques while bacteria were isolated using standard methods and identified using the API 20E systems. The antibiogram tests were carried out using the Müller-Hinton antibiotic disc diffusion method. Antibiotics used belonged to the β-lactam, Quinolones and Aminoglycoside groups. The results obtained show that these waters are slightly alkaline (pH>7.5) and contain dissolved ions (electrical conductivity>600µS/cm; TDS>120mg/L). These waters host various Proteus species such as P. mirabilis, P. penneri and P. vulgaris, which were mostly represented in hospital wastewater. The prevalence of antimicrobial resistance varied with respect to the Proteus species and antibiotic groups. All Proteus strains were resistant to β-lactams and Quinolones. Besides, 41.8% of strains of isolated species were resistant to Gentamycin and 87.5% were sensitive to Amikacin. Most of the bacteria strains isolated in wastewater and surface water were resistant to all the antibiotics tested. Many bacterial strains tested were multi-resistant (82.76%). This multidrug resistance was more expressed in P. mirabilis and P. vulgaris species isolated from wastewater and upstream river. This represents a health risk for humans and the aquatic environment.

A chemical and microbiological study was conducted on twelve dairy farms in the West Region of Cameroon (Central Africa) during the period 2019-2020. Two hundred and sixteen samples of drinking water, green fodder consumed by dairy cows and raw milk produced were analyzed. Calcium and Magnesium contents were assessed by volumetry and atomic absorption spectrometry methods. Lactobacilli, yeasts and molds were isolated on solid culture media by surface spreading techniques. The average Ca2+ concentrations were 42 mg/l, 1674 mg/kg and 1215 mg/l, in the drinking water, green fodder and milk produced respectively. That of Mg2+ was 26 mg/l, 1913 mg/kg and 160 mg/l respectively. The Ca2+ content of the raw milk produced was not significantly different (p>0.05) from that of the green fodder consumed by the cows. However, the drinking water had a significantly lower Ca2+ and Mg2+ content than the green fodder consumed and the raw milk produced (p0.05). Similarly, the yeasts and molds abundance dynamics in the drinking water of the cows were not significantly different from those in the milk produced (p>0.05).&nbsp

International audience; The present study aimed to assess the abundance dynamics 2 spore forming bacteria of sanitary importance Bacillus cereus and B. thuringiensis, in the rain and groundwater in urbanized area in Cameroon (Central Africa) and potential impact of some abiotic parameters. The bacteriological analyzes were made by cultures on agar media and the chemical analyzes by spectrophotometry. It appears that heterotrophic aerobic mesophilic bacterial abundances ranged from 1x10 6 to 1x10 8 CFU/100µL in wells and from 9x10 6 to 196x10 6 CFU/100µL in rainwater. The abundances of B. thuringiensis reached 320 CFU/100µL in wells, and 730 CFU/100µL in rainwater. That of B. cereus reached 340 CFU/100µL in wells, and 12x10 2 CFU/100µL in rainwater. The pH of wells fluctuated between 5.05 and 7.33 whereas that of rainwater varied from 6.12 to 6.88. Electrical conductivity values ranged from 111 to 885 µS/cm in wells, and varied from 3 to 92 µS/cm in rainwater. Both media contains nitrate, nitrogen ammonia, phosphate, dissolved CO 2 and O 2 and their concentration undergoes spatio-temporal variations. Correlations coefficients between meteorological/chemical parameters and the bacterial abundance dynamics undergoes spatial variation on one hand, and varied according to a given abiotic parameter and the bacterial species considered on the other hand. The relationships between the properties of the previous month's rainwater on the abundance dynamics of the microflora in sampled wells during the current month, referred to as a delayed impact, showed a various degrees of influence, suggesting that the properties of the sampled groundwater would mainly result from the interactions of the confounding factors, and not only due to the rainfall or rainwater properties.

International audience; The present study aimed to assess the abundance dynamics 2 spore forming bacteria of sanitary importance Bacillus cereus and B. thuringiensis, in the rain and groundwater in urbanized area in Cameroon (Central Africa) and potential impact of some abiotic parameters. The bacteriological analyzes were made by cultures on agar media and the chemical analyzes by spectrophotometry. It appears that heterotrophic aerobic mesophilic bacterial abundances ranged from 1x10 6 to 1x10 8 CFU/100µL in wells and from 9x10 6 to 196x10 6 CFU/100µL in rainwater. The abundances of B. thuringiensis reached 320 CFU/100µL in wells, and 730 CFU/100µL in rainwater. That of B. cereus reached 340 CFU/100µL in wells, and 12x10 2 CFU/100µL in rainwater. The pH of wells fluctuated between 5.05 and 7.33 whereas that of rainwater varied from 6.12 to 6.88. Electrical conductivity values ranged from 111 to 885 µS/cm in wells, and varied from 3 to 92 µS/cm in rainwater. Both media contains nitrate, nitrogen ammonia, phosphate, dissolved CO 2 and O 2 and their concentration undergoes spatio-temporal variations. Correlations coefficients between meteorological/chemical parameters and the bacterial abundance dynamics undergoes spatial variation on one hand, and varied according to a given abiotic parameter and the bacterial species considered on the other hand. The relationships between the properties of the previous month's rainwater on the abundance dynamics of the microflora in sampled wells during the current month, referred to as a delayed impact, showed a various degrees of influence, suggesting that the properties of the sampled groundwater would mainly result from the interactions of the confounding factors, and not only due to the rainfall or rainwater properties.

International audience; Based on morphological, morphometric and infraciliature criteria, as evidenced by the ammoniacal pyridinated silver carbonate technique and 4',6-diamidino-2-phenylindole (DAPI) staining, we contribute to the knowledge of four new ciliated protozoa species from the digestive tract of earthworms (Oligochaete: Glossoscolecidae), collected on the banks of the Nkam River (Cameroon). These new species belong to the Class Armophorea, the genera Nyctotherus and Nyctotheroides. In the genus Nyctotherus, three species are described: N. nkamensis n. sp. (ovoid, 85-138 µm × 52-115 µm), N. emini n. sp. (ovoid, 66-185 µm × 50-95 µm), and N. renimorphus n. sp. (kidney form, 125-220 µm × 75-180 µm). They have in common the presence of an apical secant system on their right side. In the genus Nyctotheroides, the species N. ndogbeleensis n. sp. (elongated form, 75-120 µm × 25-40 µm) is characterized by the existence of three secant systems on both sides: an apical secant system on the right side and two secant systems (the apical and the caudal) on the left side. Contrary to known congeners, the species described in this study have a very pronounced polymorphism.