Background: Gonorrhea is a major sexually transmitted disease worldwide and for its control, effective treatment is essential. However as more strains of Neisseria gonorrhoeae continuously develop resistance to several drugs, this strategy obliges scientists to discover newer effective drugs. Objectives: To ascertain whether crude leaf and root extracts of Cassia alata (Caesalpiniaceae) have antimicrobial activity against clinically resistant Neisseria gonorrhoeae bacteria. To determine and compare the MICs of their ether and methanol extracts. Materials and methods: Ether and methanol extracts were prepared from the plant parts. 12-375mg/ml of serially diluted ether extracts in DMSO and methanol extracts in water were tested using agar-well diffusion method against Neisseria gonorrhea clinical isolate cultured on MTM agar. MICs were determined from corresponding concentration-response curves. Ceftriaxone was used as positive control, whereas DMSO and water as negative controls. Results: All the crude extracts showed concentration-dependent Neisseria gonorrhea inhibition. Ether extracts for both leaves and roots gave lower MICs compared to those of methanol. Ether root extract showed the highest potency. Conclusions: Both the leaf and the root of Cassia alata plant have activity against clinically resistant Neisseria gonorrhoeae; the root having the higher activity. Lipophilic solvent, ether, give more potent antigonorrhoeal extracts. As expected Cassia alata plant in Central Uganda also has antibacterial activity.

The basis of Haemophilus influenzae type b (Hib) and Neisseria meningitidis serogroup C (MenC) glycoconjugates binding to aluminum-containing adjuvants was studied. By measuring the amount of polysaccharide and protein in the non-adsorbed supernatant, the adjuvant, aluminum phosphate, AlPO4, was found to be less efficient than aluminum hydroxide, Al(OH)3 at binding to the conjugates, at concentrations relevant to licensed vaccine formulations and when equimolar. At neutral pH, binding of TT conjugates to AlPO4 was facilitated through the carrier protein, with only weak binding of AlPO4 to CRM197 being observed. There was slightly higher binding of either adjuvant to tetanus toxoid conjugates, than to CRM197 conjugates. This was verified in AlPO4 formulations containing DTwP–Hib, where the adsorption of TT-conjugated Hib was higher than CRM197-conjugated Hib. At neutral pH, the anionic Hib and MenC polysaccharides did not appreciably bind to AlPO4, but did bind to Al(OH)3, due to electrostatic interactions. Phosphate ions reduced the binding of the conjugates to the adjuvants. These patterns of adjuvant adsorption can form the basis for future formulation studies with individual and combination vaccines containing saccharide-protein conjugates.

Pseudomonas aeruginosa causes various infections in humans both in hospital and community settings. Mangifera indica Linnaeus bark and dry Psidium guajava Linnaeus leaves have individually demonstrated activity against P. aeruginosa. This study aimed to assess the combined antibacterial activity of methanolic extracts of dry M. indica bark and dry P. guajava leaves on Multidrug-Resistant P. aeruginosa. Different proportion combinations of P. guajava and M. indica were assessed for antipseudomonal activity using Agar well diffusion method. Colistin was the positive control. The Fractional Inhibitory Concentration Index (FICI) was also determined. The combination of methanolic extracts of P. guajava leaves (35 mg/mL) and M. indica bark (6.25 mg/mL) had a superior antibacterial effect on Multidrug-Resistant P. aeruginosa when compared with the individual extracts used alone (p˂0.05), save for P. guajava (100 mg/mL) (p = 0.1373). Colistin was significantly more active on MDR P. aeruginosa than all the test extract concentrations used. This combination of M. indica bark and P. guajava leaves methanolic extracts had a FICI of 0.2434. This study demonstrates that the combination of P. guajava leaves (35 mg/mL) and M. indica bark (6.25 mg/mL) has synergistically enhanced activity against MDR P. aeruginosa. Keywords: Antipseudomonal, MDR Pseudomonas aeruginosa, Mangifera indica, and Psidium guajava