Effects of Industrial Agriculture and Urbanization on Structure and Functional Organization of Macroinvertebrate of Coastal Streams in Cameroon

The impact of land use changes on watercourses is poorly documented in Cameroon. Therefore, this study examines the effects of agriculture and urbanization on water quality, the structure and functional organization of macroinvertebrates of streams in the coastal zone of Cameroon. Nine sampling stations including three per catchment area with different land occupations (agricultural, urban and forest) were selected. Benthic macroinvertebrates were sampled monthly from February to July 2018 and the physicochemical variables were measured simultaneously. The urban and agricultural streams showed highly polluted waters with high nutrient and suspended matter content, whereas the forest stream waters are moderately polluted. In addition, the hierarchical ascending classification indicated a proximity in water quality between the agricultural and forest streams for which the main physicochemical variables did not vary significantly. With regards to macroinvertebrates, the forest watercourse is characterized by the proliferation of pollution-sensitive taxa, high diversity indices and complex trophic structuring, indicating its good ecological status. In contrast the urban watercourse, heavily polluted is characterized by low diversity indices reflecting a simplification of the structure of stands dominated by the pollution-tolerant collector-gatherer stands. The majority of biological indices and functional feeding groups were not significantly different between the agricultural and forest streams, suggesting a less pronounced impact of agriculture on macroinvertebrates. Our results showed that, riparian vegetation even though constituted of perennial crops, reduces the effects of agricultural inputs on streams and promotes the establishment of diversified macroinvertebrate communities.

Antibiogram of Escherichia coli and Pseudomonas Strains Isolated from Wastewater Generated by an Abattoir as It Journeys into a Receiving River

Untreated wastewater from abattoir operations contains nutrients and other components that aid the growth of microorganisms especially bacteria. They also serve as a habitat for potentially pathogenic bacteria which might be a source of public health concern. The study was carried out to determine the antibiotics susceptibility profile of Gram-negative bacteria (Pseudomonas and Escherichia coli) to selected antibiotics. Wastewater samples were collected from ten different sampling points and cultured on Eosin Methylene Blue (EMB) and King’s B medium. The bacterial strains obtained from the wastewater samples were subjected to antibiotics susceptibility tests, using the disc diffusion technique. A total of 60 Pseudomonas and 100 Escherichia coli were isolated out of which none of the Pseudomonas strains showed resistance to imipenem, colistin sulphate, meropenem and aztreonam, while 100% resistance was observed to ceftazidime and piperacillin. All the Escherichia coli strains were resistant to oxacillin and ceftazidime, while the percentage resistance to aztreonam, ertapenem, cefoxitin and tetracyline was 6%, 11%, 43% and 58% respectively. Eighty-five percent (85%) of the total Escherichia coli showed resistance to more than two antibiotics, while 14% showed resistance to ceftazidime and oxacillin, with only one isolate showing resistance to ceftazidime and cefoxitin. There is the need for an effective treatment of wastewater generated from abattoir operations to prevent the potential spread and transmission of antibiotic resistant bacteria to the human population who depends heavily on some of the water bodies, receiving input from abattoir wastes.

Heavy Metals and Antibiotics Susceptibility Profiles of <i>Staphylococcus aureus</i>Isolated from Several Points Receiving Daily Input from the Bodija Abattoir in Ibadan, Oyo State, Nigeria

Indiscriminate and unguided discharge of untreated wastewater especially from abattoirs can constitute a public health threat and also stimulate the onset of co-resistance to metal and antibiotics in environmental microorganisms. It has been shown that microorganisms especially bacteria that have the capacity to resist antibiotics and heavy metals, may constitute a public health threat. This study was therefore conducted to determine the susceptibility and tolerance profile of Staphylococcus aureus isolated from abattoir effluent flowing into a receiving river around Bodija market in Ibadan to a range of antibiotics and heavy metals. Ten points were selected for sampling, and the samples were cultured on nutrient agar and mannitol salt agar. A total of 22 Staphylococcus aureus strains were obtained. They were subjected to increasing concentration of six heavy metals [lead (Pb), copper (Cu), zinc (Zn), chromium (Cr), cadmium (Cd), nickel (Ni)] and five antibiotics. Of the total isolates, 41% were resistant to all the six metals at 1500μg/ml concentration, while the others showed various degree of resistance. A percentage resistance of 22.7% was observed for tetracycline, 100% to ceftazidime, 9.1% to ciprofloxacin and vancomycin while 63.6% of the strains were resistant to oxacillin. All the strains but two showed resistance to all the metals tested, while multiple resistance to antibiotics was also observed. Further studies need to be carried out on the mechanisms of resistance of these strains.

Influence of Anthropogenic Pollution on the Abundance Dynamics of Some Freshwater Invertebrates in the Coastal Area of Cameroon

The abundance dynamic of some freshwater invertebrates in relation with the abiotic factors of the medium was studied from March 2013 to March 2014 on the main streams of the Wouri and Sanaga basins. Individuals of Copepoda, Atyidae, Chironomidae and Physidae were collected, identified and counted. Samplings were carried out monthly;meanwhile measurements of the environmental variables were taken. Results of the physico-chemical analyses revealed that water of the Sanaga basin is globally well oxygenated (77% - 92%) and faintly mineralized (14 - 107 μS/cm), excepted in the stations receiving house-hold pollutants. Inversely, in the Wouri basin, waters are hypoxic with high content of organic matters (27.79 ± 9.43 mg/L). During rainy season (June-September), there is a dilution-dispersion of the organic matter due to stormwaters. Concerning biological analyses, the families of Physidae and Chironomidae were more abundant in urban stations than in stations situated in suburban area, especially during low water level period, showing that they are well adapted to anthropogenic and organic pollutions. The hypoxic conditions of urban waterways do not favor the proliferation of sensitive taxa such as Atyidae and Copepoda. These taxa preferred well oxygenated waters with rapid flow, and are more abundant during rainy season in stations located in suburban area or which are less subjected to anthropogenic disturbances.

Recent developments of lactic acid bacteria and their metabolites on foodborne pathogens and spoilage bacteria:Facts and gaps

Lactic acid bacteria(LAB)are common microorganisms found in various ecosystems including in plants,fermented foods,and the human body.Exploring the biodiversity of lactic acid microflora and characterization of LAB is a new approach to form a variety of starter communities to create innovative nutritional food matrices.There has been growing interest in LAB isolated from non-dairy environments as these bacteria exhibit significant metabolic diversity and have unique taste-forming activities.Disease may be prevented,or treated by LAB but the treatment of disease conditions with LAB is highly dependent on the host's microbiome and diet and varies in both effectiveness and side effects from individual to individual.Future perspectives on the study of LAB may be related to the expansion of our knowledge in the fields of genetics and genetic engineering.The application of genetic science may help to improve existing strains and develop new strains with characteristics designed for specific purposes.Therefore,the preservative effects of LAB and their metabolites,as well as their interaction on the growth of food borne pathogens and food spoilage microorganisms were elucidated.In addition,the competitive models for microbial growth between LAB and other microorganisms as well as the role of LAB in the elimination of toxic compounds in food products were discussed.Moreover,the review provided an overview of the risks and benefits of using LAB in the food industry.