Isolation and molecular identification of Salmonella with high multidrug resistance to first line typhoid antibiotics in Southwest Cameroon

Background:The prevalence of typhoid fever in Cameroon is high. However, studies on susceptibility of Salmonella to the recommended antibiotics are few and not extensive. This study investigated the susceptibility of Salmonella isolated from clinical specimens in the South West region of Cameroon and the genes responsible for their antibiotic resistance. Methods: Salmonellawas isolated from clinical specimens collected from some medical laboratories in the study area by culture on Salmonella Shigella agar. Identification and resistance genes analysis were done using biochemical tests, PCR and gene sequencing. Disc diffusion test was done using 11 commercial antibiotics and minimum inhibitory concentrations determined by microdilution test to assess antibiotic susceptibility profile. The Multi-Antibiotic Resistance (MAR) index values were calculated. Results: Salmonella was isolated from 50 out of 115 specimens, of which 46 (92 %) were multidrug resistant (MDR) with MAR indices > 0.2.The MDR isolates showed high resistance to penicillins and low resistance to ciprofloxacin. PCR revealed that antibiotic resistance was largely due to the tem-1, Sul 1, dfrA1, floR genes. Sequencing revealed double mutations at codons 83 (Ser83-Phe) and 87 (Asp87-Gly) and one mutation at codon 83 (Ser83-Trp) in the quinolone resistance determining regions of the gyrA gene in two isolates. Conclusion: This study has revealed presence of MDR Salmonella enterica isolates in Southwest Cameroon with several resistance genes. This finding will guide use of antibiotics in treatment of Salmonella infections in the study area and justifies the search for new efficacious antibacterials against the MDR strains

Vegetative propagation of F1 tomato hybrid (Solanum lycopersicum L.) using different rooting media and stem-nodal cuttings

Tomato (Solanum lycopersicum L.) cultivated globally for its multifunctional uses (chiefly culinary and medicinal), is propagated mainly through seeds with most commercial varieties being hybrid. With the adoption of improved high-yielding and disease-resistant commercial hybrids, seeds have become an expensive input in tomato production. The cost of hybrid seeds could be prohibitive to resource-poor farmers. If they use seeds from mass selection, the resultant population will be segregated. The main objective of the research is to identify F1 tomato hybrid cultivated in Buea, to estimate the number of cuttings generated from different stages of apical decapitation/topping, to test the efficacy of one and two nodal cuttings and substrate composition on the sprouting of stem cuttings and lastly to compare the vigor of seedlings from nodal cuttings and seedlings from seeds. The study was carried out within the Buea municipality, in the South West Region of Cameroon, the field experiments were carried out in the Faculty of Agriculture and Veterinary Medicine Research and Teaching Farm. A stratified random sampling design was used to sample stakeholders in Buea. A Randomized Complete Block Design (RCBD) was used for the topping/decapitation experiment, while a Completely Randomized Design (CRD) was used for the rooting media tested with one nodal cuttings and two nodal cuttings experiment, as well as the comparison of seedlings from stem cuttings and seeds experiment. The study showed that Cobra F1 is the most cultivated tomato hybrid in Buea, followed by Beggar Brother, Rio Grande and Rio Power. Topping tomato seedlings at the 6-leaf stage produce more branches compared to no topping and topping at 4 leaf stage. The number of branches obtained through topping can be estimated using the regression equation, y = 0.88x + 3.05 with an R2 value of 0.96. The shoot length and number of leaves of two nodal cuttings were significantly higher than those of one nodal cutting. M4 (1 part of soil + 2 parts of sawdust) performed better than the other rooting media. Seedlings obtained through cuttings were significantly different from seedlings obtained through seeds for the number of leaves, but not for plant height and stem diameter