AIM: Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogenic bacterium that causes both hospital- and community-acquired infections, and for which single-drug treatments are becoming less efficient. Rhizoma coptidis has been used for more than two thousand years in China to treat diarrhea, fever, and jaundice. In this study, the anti-MRSA activity of Rhizoma coptidis is examined and its effective components sought. METHODS: The mecA and norA genes were determined by PCR amplification and sequencing. Drug susceptibility of Staphylococcus aureus ATCC43300 was performed using the VITEK2 compact system. The chemical fingerprint of Rhizoma coptidis was investigated using HPLC and preparative liquid chromatography, and the anti-MRSA activity was determined using an improved broth microdilution method. RESULTS: The drug susceptibility test revealed that the penicillin-binding protein phenotype of the strain changed in comparison to penicillin-sensitive Staphylococcus aureus. Ten batches of Rhizoma coptidis showed anti-MRSA activity on the norA-negative Staphylococcus aureus strain, as well as the strain that contained a norA gene. The spectrum-effect relationship revealed that the berberine alkaloids were the effective components, within which berberine, coptisine, palmatine, epiberberine, and jatrorrhizine were the major components. CONCLUSION This study lays a foundation for in vivo studies of Rhizoma coptidis and for the development of multi-component drugs.
Anti-Bacterial Agents ; chemistry ; pharmacology ; Bacterial Proteins ; genetics ; metabolism ; China ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; Methicillin-Resistant Staphylococcus aureus ; drug effects ; genetics ; growth & development ; metabolism ; Microbial Sensitivity Tests ; methods ; Ranunculaceae ; chemistry ; Rhizome ; chemistry

BACKGROUND: We evaluated the performance of three chromogenic media (Brilliance agar I [Oxoid, UK], Brilliance agar II [Oxoid], and ChromID MRSA [Biomerieux, France]) combined with broth enrichment and the Xpert MRSA assay for screening of methicillin-resistant Staphylococcus aureus (MRSA). METHODS: We obtained 401 pairs of duplicate nasal swabs from 321 patients. One swab was suspended overnight in tryptic soy broth; 50-microL aliquots of suspension were inoculated on the three chromogenic media. Brilliance agar I and II were examined after 24 hr, and ChromID MRSA, after 24 and 48 hr. The paired swab was processed directly using real-time PCR-based Xpert MRSA assay. RESULTS: True positives, designated as MRSA growth in any of the culture media, were detected with the prevalence of 17% in our institution. We report the sensitivity, specificity, positive predictive value, and negative predictive value of MRSA growth as follows: 92.3%, 94.0%, 75.9%, and 98.4% in Brilliance agar I (24 hr); 92.7%, 97.9%, 90.0%, and 98.5% in Brilliance agar II (24 hr); 95.6%, 95.8%, 82.3%, and 99.1% in ChromID MRSA (24 hr); 100%, 92.5%, 73.1%, and 100% in ChromID MRSA (48 hr); 92.6%, 96.7%, 85.1%, and 98.5% in Xpert MRSA assay. The agreement between the enriched culture and Xpert MRSA assay was 96.0%. CONCLUSIONS: Three chromogenic culture media combined with enrichment and Xpert MRSA assay demonstrated similar capabilities in MRSA detection. The Xpert MRSA assay yielded results comparable to those of culture methods, saving 48-72 hr, thus facilitating earlier detection of MRSA in healthcare settings.
Bacterial Proteins/genetics ; Bacterial Typing Techniques/*methods ; Chromogenic Compounds/chemistry/*metabolism ; Culture Media/chemistry ; DNA, Bacterial/analysis ; Humans ; Methicillin-Resistant Staphylococcus aureus/*genetics/growth & development/*isolation & purification/metabolism ; Nasal Cavity/*microbiology ; Reagent Kits, Diagnostic ; *Real-Time Polymerase Chain Reaction ; *Staphylococcal Infections/diagnosis/microbiology