Effects of KMnO4 amounts on antibacterial properties of activated carbon for efficient treatment of northern Benin hospital wastewater in a fixed bed column system.

In this study, the wastewater from the Departmental Hospital Center of Atacora in Benin was characterized and then treated with activated carbon/potassium permanganate (AC/KMnO4) composite in a fixed bed column system. The AC/KMnO4 composites with impregnation ratios range 0.025-0.100 were prepared from peanut shell activated carbon and potassium permanganate. The wastewater characteristics revealed that 75% of Escherichia coli strains identified were extended-spectrum lactamases (ESBL) with CTX-M dominance, while 25% of Staphylococcus aureus strains produced Panton and Valentine leucocidin and 77.80% of Salmonella typhi strains were resistant to Trimethoprim/Sulfamethoxazole. The fixed bed column system results showed removal efficiency of 72.18 ± 4.98% turbidity, 63.12 ± 4.11% COD, 0.70 ± 0.04 log10 against E. coli and 3.82 ± 0.01 log10 against S. typhi strains using activated carbon as adsorbent with 0.7 cm bed depth after 3 h of treatment. The composite adsorbent AC/KMnO4 significantly increased the effectiveness of treatment due to the strong oxidant power of KMnO4 in the composite material. The results depicted a removal rate of 83.88 ± 5.00%, 89 ± 1.95%, 90 ± 0.65% turbidity, 66.47 ± 1.62%, 69.82 ± 2.00%, 78.20 ± 2.82% COD, 2.0 ± 0.08 log10, 5.0 ± 0.07 log10 against E. coli and 3.82 ± 0.01 log10 against S. typhi strains using AC/KMnO4 with 0.025, 0.050 and 0.100 ratios respectively at 0.7 cm bed depth. Finally, AC/KMnO4 revealed more adsorption potential and antibacterial property than AC, hence, the composite material could be used as a cost-effective adsorbent for efficient removing of multi-resistant bacteria from hospital wastewater.

The ace-1 Locus Is Amplified in All Resistant Anopheles gambiae Mosquitoes: Fitness Consequences of Homogeneous and Heterogeneous Duplications.

Gene copy-number variations are widespread in natural populations, but investigating their phenotypic consequences requires contemporary duplications under selection. Such duplications have been found at the ace-1 locus (encoding the organophosphate and carbamate insecticides' target) in the mosquito Anopheles gambiae (the major malaria vector); recent studies have revealed their intriguing complexity, consistent with the involvement of various numbers and types (susceptible or resistant to insecticide) of copies. We used an integrative approach, from genome to phenotype level, to investigate the influence of duplication architecture and gene-dosage on mosquito fitness. We found that both heterogeneous (i.e., one susceptible and one resistant ace-1 copy) and homogeneous (i.e., identical resistant copies) duplications segregated in field populations. The number of copies in homogeneous duplications was variable and positively correlated with acetylcholinesterase activity and resistance level. Determining the genomic structure of the duplicated region revealed that, in both types of duplication, ace-1 and 11 other genes formed tandem 203kb amplicons. We developed a diagnostic test for duplications, which showed that ace-1 was amplified in all 173 resistant mosquitoes analyzed (field-collected in several African countries), in heterogeneous or homogeneous duplications. Each type was associated with different fitness trade-offs: heterogeneous duplications conferred an intermediate phenotype (lower resistance and fitness costs), whereas homogeneous duplications tended to increase both resistance and fitness cost, in a complex manner. The type of duplication selected seemed thus to depend on the intensity and distribution of selection pressures. This versatility of trade-offs available through gene duplication highlights the importance of large mutation events in adaptation to environmental variation. This impressive adaptability could have a major impact on vector control in Africa.