ABSTRACT
Methicillin-resistant Staphylococcus aureus (MRSA) carrying the important virulence determinant, Panton-Valentine leukocidin (PVL), is an emerging infectious pathogen associated with skin and soft tissue infections as well as life-threatening invasive diseases. In carrying out the first PVL prevalence study in Nepal, we screened 73 nosocomial isolates of S. aureus from 2 tertiary care Nepali hospitals and obtained an overall PVL-positivity rate of 35.6% among the hospital isolates: 26.1% of MRSA and 51.9% of methicillin sensitive S. aureus (MSSA) isolates were found to be positive for the PVL genes. PVL prevalence was not associated with a specific (i) infection site, (ii) age group, or (iii) hospital of origin. It was found to be positively associated with heterogeneous MRSA (73.3%) compared to homogeneous MRSA (3.2%) and MSSA (51.9%); negatively associated with multiresistant MRSA (22%) compared to nonmultiresistant MRSA (60%) and MSSA (51.9%); and positively associated with macrolide-streptogramin B resistance (93.8%) compared to macrolide-lincosamide-streptogramin B resistance (0%) and no-resistance (45.8%) types. Macrolide-streptogramin B resistance was confirmed by the presence of msr(A) gene. Restriction pattern analyses provided evidence to support the circulation of a limited number of clones of PVL-positive MRSA, arguing for the adaptability of these isolates to a hospital setting.
Subject(s)
Bacterial Toxins/genetics , Cross Infection/genetics , Exotoxins/genetics , Leukocidins/genetics , Methicillin-Resistant Staphylococcus aureus/genetics , Staphylococcal Infections/genetics , Cross Infection/microbiology , Cross Infection/pathology , Humans , Methicillin/therapeutic use , Methicillin-Resistant Staphylococcus aureus/drug effects , Methicillin-Resistant Staphylococcus aureus/pathogenicity , Microbial Sensitivity Tests , Nepal , Staphylococcal Infections/drug therapy , Streptogramin B/therapeutic use , Tertiary Care CentersABSTRACT
Several herbal plants such as Chinese herb Rhizoma Coptidis have been reported to possess antidiabetic activity. Berberine is its major active constituent and functions as an insulin sensitizer and insulin secretagogue. It has been reported to modulate several signaling pathways and targets. The objective of the current study is to investigate if berberine can function as a ligand of fatty acid receptor GPR40, which stimulates glucose dependent insulin secretion. Towards this objective, a mammalian cell line with stable overexpression of GPR40 was generated and characterized. Berberine stimulated calcium mobilization with an EC(50) of 0.76 microM in this GPR40 overexpressing cell line. Further, berberine stimulated glucose dependent insulin secretion from rat pancreatic beta cell line. This suggests that berberine functions as an agonist of fatty acid receptor GPR40 and might be a novel antidiabetic mechanism of action for berberine.
