Accessory Gene Regulator Polymorphism and Vancomycin Minimum Inhibitory Concentration in Methicillin-Resistant Staphylococcus aureus

作者：Park Min Jeong; Kim Han Sung; Kim Hyun Soo; Kim Jae Seok; Song Wonkeun; Kim Mi Young; Lee Young Kyung; Kang Hee Jung

来源：Annals of Laboratory Medicine, 2015, 35(4): 399-403.

DOI：10.3343/alm.2015.35.4.399

• Agr polymorphism
• Staphylococcus aureus
• Vancomycin

Background: Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia with a vancomycin minimum inhibitory concentration CMIC) of 2 mu g/mL presents a high rate of therapeutic failure in response to vancomycin. In addition, polymorphism in accessory gene regulator (agr) is associated with vancomycin therapeutic effects. The association between agr polymorphism and vancomycin MICs was investigated in MRSA isolates.
Methods: Agr group-specific PCR was conducted on 118 MRSA bloodstream isolates. Vancomycin susceptibility tests were conducted, while E-test GRD (bioMerieux SA, France) was used to detect heterogeneous vancomycin-intermediate S. aureus (hVISA).
Results: Of the 118 MRSA isolates, 59 (50.0%), 43 (36.4%), and 10 (8.5%) isolates belonged to agr group I, II, and III, respectively. Six isolates could not be classified. Twenty-six, 73, and 19 isolates presented a vancomycin MIC of 2, 1, and 0.5 mu g/mL, respectively. Nine (34.6%), 14 (53.8%), and 2 (7.7%) isolates with MICs of 2 mu g/mL belonged to agr group I, II, and Ill, respectively. Thirty-seven (50.6%), 26 (35.6%), and 6 (8.2%) isolates with MICs of 1 mu g/mL belonged to agr group I, II, and III, respectively. Thirteen (68.4%), 3 (15.8%), and 2 (10.5%) isolates with MICs of 0.5 mu g/mL belonged to agr group I, II, and III, respectively. The agr group II presented more isolates with MIC of 2 mu g/mL (32.6%) than the agr non-group 11 (16%). Four isolates tested positive for hVISA. Three of them belonged to agr group II.
Conclusions: MRSA isolates with vancomycin MIC of 2 mu g/mL were more common in agr group II than in agr non-group II.

• 出版日期2015-7