Ouabain potentiates the antimicrobial activity of aminoglycosides against Staphylococcus aureus.

BACKGROUND: Staphylococcus aureus is a notorious pathogen which often causes nosocomial and community attained infections. These infections steadily increased after evolving the resistance due to indecorous practice of antibiotics and now become a serious health issue. Ouabain is a Na+/K+-ATPase inhibitor that leads to increase the heart contraction in patients with congestive heart failure. METHODS: In the present study, in vitro antimicrobial effect of ouabain together with aminoglycosides was determined against clinical and non-clinical S. aureus strains. Using checkerboard, Gentamycin uptake and biofilm assays, we analysed he interactions of ouabain with aminoglycosides. RESULTS: Ouabain induced the staphylocidal potency of aminoglycosides by remarkably reducing the MIC of gentamycin (GEN) by 16 (0.25 µg/mL), 8 folds (0.5 µg/mL) amikacin (AMK); and 16 folds (1.0 µg/mL) with kanamycin (KAN), compared to their individual doses. OBN severely reduced cell viability within 60 min with GEN (1 µg/mL), KAN (2 µg/mL) and 90 min with AMK (1 µg/mL). This bactericidal effect was enhanced due to GEN uptake potentiated by 66% which led to increase the cell permeability as revealed by leakage of bacterial ATP and nitrocefin assay. The biofilm adherence disrupted by 80 and 50% at 5 mg/mL and 1.5 mg/mL OBN and 50 and 90% biofilm formation was inhibited at 5 mg/mL (MBIC50) and 10 mg/mL (MBIC90), respectively. Moreover, OBN with GEN further induced biofilm inhibition by 67 ± 5% at pH 7.0. CONCLUSIONS: Taken together, we established that OBN synergizes the antimicrobial activity of aminoglycosides that induces cell killing due to intracellular accumulation of GEN by disturbing cell homeostasis. It may be proven an effective approach for the treatment of staphylococcal infections.

A review on cassane and norcassane diterpenes and their pharmacological studies.

The natural Cassane and norcassane diterpenes are biosynthetic rearrangement products of Pimarane precursor in the biosynthetic pathway of diterpenes. Their distribution is highly restricted to various genera of Fabaceae family (especially to Caesalpinia genus). A comprehensive account of the structural diversity (322 structures, 114 references) is given in this review along with biological activities of cassane and norcassane diterpenes up to September 2011.

Caudodontia of mandibular 2nd molar with bilateral maxillary canine – premolar transposition - a case report.

Transposition of teeth is a developmental anomaly manifested by a positional interchange of two permanent teeth. It is often associated with hypodontia, peg lateral crowding, severe rotation and malformation like dilaceration and missing teeth, retained teeth and even with impaction which are clinically important for diagnosis as well as treatment plan. However, this case is a deviation from the afore mentioned group of associated anomalies. Surprisingly, in this case bilateral maxillary canine – premolar transposition is associated with idiopathic resorption of the crown of the second mandibular molar. The persistence of only the caudal part of the tooth in such a case merits denoting it as ‘Caudodontia’ by us.