[The change in sensitivity of methicillin-resistant Staphylococcus aureus to vancomycin].
OBJECTIVE
To determine the shift of susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) isolates to vancomycin in recent years.


METHODS
Antimicrobial susceptibility was determined by disk diffusion test (K-B method). The t-test was used to compare the mean diameters of zone of inhibition.


RESULTS
The clinical isolates of MRSA from 1994 to 2000 were 218, 187, 292, 237, 351, 886 and 652 in number respectively. The mean diameters (mm) of the inhibition zone of MRSA isolates each year were 19.9, 19.1, 18.6, 17.4, 18.4, 18.2 and 17.8. Comparison of the diameters of the inhibition zone of MRSA isolates (K-B method) showed that the mean diameter of the inhibition zone from the 652 MRSA isolates in 2000 was much less than that of the 218 MRSA isolates in 1994 and the difference was significant (P < 0.001). The resistant rates to chloramphenicol, ciprofloxacin, erythromycin, gentamicin, tetracycline and trimethoprim/sulfamethoxazole were 44.0%, 73.7%, 89.1%, 65.7%, 61.0% and 67.0%.


CONCLUSIONS
Our observation demonstrated that the susceptibility of MRSA to vancomycin gradually decreased from 1994 to 2000. It is important to monitor the antimicrobial susceptibility of Staphylococcus aureus to vancomycin.
Ma
Yue
Y
Division of Antibiotics, National Institute for the Control of Pharmaceutical and Biological Products, Beijing 100050, China.
Chen
Hongbo
H
Yao
Lei
L
Li
Jingyun
J
Zhang
Li
L
Hu
Changqin
C
Jin
Shaohong
S
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D008712:Methicillin / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D010406:Penicillins / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D013997:Time Factors; D014640:Vancomycin / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D010406:Penicillins; D014640:Vancomycin; D008712:Methicillin