Abstract
Background
Many genes encoding aminoglycoside modifying enzymes (AMEs) on transposon or plasmid were transferred from one strain to another strain and inserted into a staphylococcal chromosomal cassette mec (SCCmec). There are very diverse subtypes in SCCmec type to the insertion of resistant genes. Therefore, we researched the resistance rates of antibiotics and distribution of AME genes according to SCCmec type in MRSA strains.
Materials and Methods
We isolated 640 Staphylococcus aureus from non-tertiary hospitals in 2004, detected mecA, aac(6')-aph(2"), aph(3')-IIIa, and ant(4')-Ia using the multiplex PCR method, tested antibacterial susceptibility disk diffusion and minimal inhibitory concentration, and determined SCCmec type.
Results
Of 640 S. aureus isolates, MRSA rate was 39.7% and all MRSA isolates carried mecA gene. Among 214 MRSA selected, aminoglycoside-resistant rates were 98.1% in kanamycin and tobramycin, 68.7% in gentamicin, 30.8% in amikacin, and 2.8% in netilmicin. The detection rates for aac(6')-aph(2"), aph(3')-IIIa, and ant(4')-Ia were 77.1%, 13.1%, and 53.3%, respectively. Also, SCCmec type was 50.9% in SCCmec type II, 16.4% in type III, and 32.7% in type IV. The genes encoding AMEs were distributed aac(6')-aph(2") (49.5%) and aac(6')-aph(2")/ant(4')-Ia (36.7%) in SCCmec type II, aph(3')-IIIa/aac(6')-aph(2") (60%) and aac(6')-aph(2") (31.4%) in type III, and aac(6')-aph(2")/ant(4')-Ia (41.4%) and ant(4')-Ia (50%) in type IV.
Figures and Tables
Table 2
Antimicrobial Resistant Rates of Staphylococcus aureus, Against Several Antibiotics from 146 Non-tertiary Hospitals
![ic-40-32-i002](/upload/SynapseData/ArticleImage/1086ic/ic-40-32-i002.jpg)
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