Bastos M C, Mondino P J, Azevedo M L, Santos K R, Giambiagi-deMarval M
Instituto de Microbiologia Prof. Paulo de Góes-UFRJ, CCS-Cidade Universitária, Rio de Janeiro, Brazil.
Eur J Clin Microbiol Infect Dis. 1999 Jun;18(6):393-8. doi: 10.1007/s100960050306.
In this work, mupirocin resistance was correlated with the presence of plasmids in methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in the Rio de Janeiro Federal University Hospital in Brazil, where topical mupirocin has been used extensively since 1990. Of 19 strains studied, those exhibiting high-level resistance carried a large and relaxable plasmid of about 35 kb. Mupirocin-sensitive derivatives, obtained by growth at 42 C of a strain exhibiting high-level resistance, were devoid of the large plasmid, which was designated pMG1. Mupirocin resistance was transferred to strain RN8411 during overnight filter-matings at low frequencies (7.0 x 10(-9)/donor). The pMG1 plasmid was shown to be responsible for high-level mupirocin resistance in our isolates and to be incompatible with pGO1. Hybridization experiments suggested that mupirocin resistance in pMG1 is due to the presence of the ileS-2 gene. The pMG1 plasmid was successfully and bidirectionally transferred from Staphylococcus aureus to Staphylococcus epidermidis, suggesting that the latter may be a reservoir of this resistance plasmid. No transfer was detected to Staphylococcus haemolyticus. The development of self-transferable high-level mupirocin resistance should be considered when using mupirocin to control the spread of MRSA in hospitals.
在这项研究中，对巴西里约热内卢联邦大学医院分离出的耐甲氧西林金黄色葡萄球菌（MRSA）菌株，莫匹罗星耐药性与质粒的存在相关，自1990年以来该医院广泛使用局部用莫匹罗星。在所研究的19株菌株中，表现出高水平耐药的菌株携带一个约35 kb的大的可松弛质粒。通过对一株表现出高水平耐药的菌株在42℃培养获得的莫匹罗星敏感衍生物，不含该大质粒，该质粒被命名为pMG1。在低频（7.0×10⁻⁹/供体）过夜滤膜交配过程中，莫匹罗星耐药性转移至RN8411菌株。pMG1质粒被证明是导致我们分离株中高水平莫匹罗星耐药的原因，并且与pGO1不相容。杂交实验表明，pMG1中的莫匹罗星耐药性是由于ileS - 2基因的存在。pMG1质粒成功地双向从金黄色葡萄球菌转移至表皮葡萄球菌，这表明后者可能是这种耐药性质粒的储存库。未检测到向溶血葡萄球菌的转移。在使用莫匹罗星控制医院中MRSA传播时，应考虑可自我转移的高水平莫匹罗星耐药性的发展。
