Determination Of Antimicrobial Activity Of Methicillin-resistant Staphylococcus Epidermidis And Study Of In Vitro Inhitory Action Of Chinese Traditional Medicine

Objections: S.epidermidis had long been regarded as opportunistic, but its important role as pathogens and its increasing incidence had recognized and studied since 1970s. S.epidermidis wasn't thought as importance until multi-resistant strains were determined, especially increased methicillin-resistant S.epidermidis(MRSE). To investigate antibacterial susceptibility, 112 clinical isolates of S.epidermidis were identified. Observation of antibacterial activity of Chinese traditional medicine against S.epidermidis was performed by new methods, to detect which was sensitive against MRSE.Methods: All isolates of resistance to methicillin and other antibiotics were tested by agar dilution method. Antibacterial activity of Chinese traditional medicine were performed by new methods, such as M-H agar, plenty of strains, multipoint inoculating device, effective components abstained by dried decoction.Results: Methicillin-resistant S.epidermidis was detected in 72 of 112(65%) of S.epidenmdis. As a result ofincreasing ciprofloxacin usage, the overall incidence of resistance to fluoroquinolones among S.epidermidis also had been steadily increaing over the past several years. 100% of S.epidermidis were found to be resistant to ciprofloxacin. Minocydine was active of tetracyclines against staphylococci , MIC90 of minocycline to MRSE was 4 u g/ml, rate of susceptibility was 86.9%. MIC90 of rifampin was 16 n g/ml , rate of susceptibility was 82.1%. All strains were sensitive to vancomycin, rate of susceptibility of teicoplanin against MRSE was 97.3%.More susceptible Chinese traditional medicine were found by antimicrobial tests of 30 kinds of Chinese traditional medicine, such as Galla chinensis, catechu, etc. Antimicrobial activity of Chinese traditional medicine had performed against MRSE by MIC90<1:80. MIC^ of Galla chinensis against MRSE was 1:1280, and MIC90 against MSSE was 1:2560. MIC90 of Catechu against MRSE was 1:320, and MIC90 against MSSE was 1:160. Activity of Chinese traditional medicine against MRSE, MSSE was similar by statistic method, So was MRSA, MSSA.Conclusions: Staphylococci, both methicillin resistant and methicillin susceptible, were found to be uniformly susceptible to the fluoroquinolones when these drugs were introduced in the mid 1980s. However, resistance to fluoroquinolones also had been steadily increasing, resistanceof ciprofloxacin was 100%. Minocycline is the most active of the tetracyclines against staphylococci, especially those that are methicillin resistant. Domestic minocycline was producted in 1990s. It showed antimicrobial activity of domestic minocycline was effective against MRSE. Rifampin, which was used to therapy tuberculosis, was more effective against staphylococci. Vancomycin resistance against MRSE wasn't found in the study. Domestic teicoplanin which was produced in 2000, was susceptible against MRSE, rate of susceptibility was 97.3%. So glycopeptides was still effective against staphylococci. More susceptible Chinese traditional medicine against MRSE were found by antimicrobial tests of 30 kinds of Chinese traditional medicine, such as Galla chinensis, Catechu. Galla chinensis decoction diluted 1280 folds could still inhibit 90% MRSE strains, and 100% MSSE. Activity of Chinese traditional medicine against MRSE, MSSE was similar by statistic method. It showed mechanism of resistance to Chinese traditional medicine was different from that of antibiotics. Since Chinese traditional medicine was economic and less to acquire resistance, if we exploited new dosage and found effectively antimicrobial component, We should find a new road in therapying infection with MRSE.