Hen Karen, Imafuku Yuji, Yoshida Hiroshi
Department of Laboratory Medicine, Fukushima Medical University, School of Medicine, Fukushima 960-1247, Japan.
Rinsho Byori. 2008 Nov;56(11):955-60.
Methicilllin-resitant Staphylococcus aureus (MRSA) is still the most important bacterium for hospital infection control, and is known to exhibit beta-lactam resistance. Moreover, the increase in PBP2'-producing methicillin-resistant coagulase-negaive Staphylococcus (MR-CNS), especially methicillin-resistant S. epidermidis (MRSE) has been problematic. In this study, we investigated the induction of PBP2' by MPIPC, other antibiotics and disinfectants in MRSE.
The bacterial strains used were MRSE isolated in our clinical laboratory. MRSA-LA 'Seiken' was used for the detection of PBP2'. To investigate induction of PBP2' by MPIPC in MRSE, MRSE was cultured on the medium containing MPIPC at 11 different concentrations from 0.0001 to 6 microg/ml, and PBP2' induction was investigated. Strains in which no induction was noted at a low MPIPC concentration were cultured with other antibiotic discs and discs impregnated with various disinfectants, and PBP2' was detected in colonies that grew around the disc and PBP2' induction was investigated.
In the culture on MPIPC-supplemented medium, PBP2' was detected in all strains at 0.01-6 microg/ml. At 0.001 and 0.0001 microg/ml, 8/10 and 4/10 were positive, respectively. Addition of another beta-lactam, particularly cephem antibiotics, induced PBP2' in some strains that were negative at 0.0001 microg/ml. In cultures with disinfectants, inhibition zones were noted, but no PBP2' was induced.
PBP2' was induced by a low beta-lactam and was not by disinfectants in MRSE.
耐甲氧西林金黄色葡萄球菌（MRSA）仍是医院感染控制中最重要的细菌，已知其具有β-内酰胺耐药性。此外，产PBP2'的耐甲氧西林凝固酶阴性葡萄球菌（MR-CNS），尤其是耐甲氧西林表皮葡萄球菌（MRSE）的增加一直是个问题。在本研究中，我们调查了MPIPC、其他抗生素和消毒剂对MRSE中PBP2'的诱导作用。
所用细菌菌株为我们临床实验室分离的MRSE。MRSA-LA“Seiken”用于检测PBP2'。为研究MPIPC对MRSE中PBP2'的诱导作用，将MRSE在含有浓度从0.0001至6μg/ml的11种不同浓度MPIPC的培养基上培养，并研究PBP2'的诱导情况。在低MPIPC浓度下未观察到诱导作用的菌株与其他抗生素纸片和浸有各种消毒剂的纸片一起培养，在纸片周围生长的菌落中检测PBP2'并研究PBP2'的诱导情况。
在添加MPIPC的培养基上培养时，在0.01 - 6μg/ml的所有菌株中均检测到PBP2'。在0.001和0.0001μg/ml时，分别有8/10和4/10为阳性。添加另一种β-内酰胺，尤其是头孢菌素类抗生素，在一些在0.0001μg/ml时为阴性的菌株中诱导出了PBP2'。在使用消毒剂的培养中，观察到抑菌圈，但未诱导出PBP2'。
在MRSE中，低浓度β-内酰胺可诱导PBP2'，而消毒剂不能诱导。
