Schneider Ines, Queenan Anne Marie, Bauernfeind Adolf
MICOER Institute, Hesseloherstrasse 4, 80802 Munich, Germany.
Antimicrob Agents Chemother. 2006 Apr;50(4):1330-5. doi: 10.1128/AAC.50.4.1330-1335.2006.
Pandoraea spp. are gram-negative, glucose nonfermenting rods detectable in blood cultures and sputa of cystic fibrosis patients. They are resistant to various antibiotic groups, with imipenem being the only active beta-lactam. We isolated an imipenem-resistant (MIC, 64 microg/ml) Pandoraea pnomenusa strain from a cystic fibrosis patient. Cloning and sequencing identified two beta-lactamases of Bush group 2d, namely, the known OXA-33, located on an integron, and the novel carbapenem-hydrolyzing oxacillinase OXA-62. OXA-62 is only distantly related to other oxacillinases (OXA-50 being closest with 43% amino acid identity). It hydrolyzes penicillins, oxacillin, imipenem, and meropenem but not expanded-spectrum cephalosporins. The blaOXA-62 gene is chromosome located. No transposable elements were found in its genetic neighborhood. With OXA-62-specific primers, blaOXA-62 could be identified in all P. pnomenusa strains and appears to be species specific. This additional mechanism of carbapenem resistance further complicates the treatment of infections caused by P. pnomenusa.
洋葱伯克霍尔德菌属细菌是革兰氏阴性、不发酵葡萄糖的杆菌，可在囊性纤维化患者的血培养物和痰液中检测到。它们对多种抗生素耐药，亚胺培南是唯一有活性的β-内酰胺类抗生素。我们从一名囊性纤维化患者中分离出一株对亚胺培南耐药（MIC为64μg/ml）的洋葱伯克霍尔德菌。克隆和测序鉴定出两种Bush 2d组β-内酰胺酶，即位于整合子上的已知OXA-33和新型碳青霉烯水解型苯唑西林酶OXA-62。OXA-62与其他苯唑西林酶的亲缘关系较远（与OXA-50最接近，氨基酸同一性为43%）。它可水解青霉素、苯唑西林、亚胺培南和美罗培南，但不水解超广谱头孢菌素。blaOXA-62基因位于染色体上。在其基因附近未发现转座元件。使用OXA-62特异性引物，可在所有洋葱伯克霍尔德菌菌株中鉴定出blaOXA-62，且似乎具有种属特异性。这种额外的碳青霉烯耐药机制使洋葱伯克霍尔德菌引起的感染治疗更加复杂。
