Horii Toshinobu, Osaki Mai, Muramatsu Hideaki
Division of Bacteriology, Department of Microbiology and Immunology, Tottori University Faculty of Medicine, Yonago, Japan.
Chemotherapy. 2008;54(4):323-7. doi: 10.1159/000151266. Epub 2007 Jul 30.
Prevalence of fluoroquinolone-resistant Klebsiella oxytoca has been reported worldwide.
We recovered ten clinical K. oxytoca isolates from patients with acute cystitis, asymptomatic bacteriuria or acute bacillary diarrhea in Japan. Out of ten isolates, one fluoroquinolone-susceptible isolate was included as a control. Fluoroquinolone resistance was characterized genetically by PCR and DNA sequencing methods. Outer membrane protein (OMP) profiles were determined by SDS-PAGE.
In nine clinical isolates of levofloxacin-resistant K. oxytoca, nucleotide sequences in the quinolone-resistance-determining regions showed amino acid mutations such as Thr83Ile and Asp87Gly in GyrA and Ser80Ile in ParC. Combined effects of reduced 36-kDa OMP production and amino acid mutations in GyrA and ParC were shown by two K. oxytoca isolates exhibiting higher minimum inhibitory concentrations for fluoroquinolones than other fluoroquinolone-resistant isolates.
In clinical K. oxytoca isolates, the various mechanisms of fluoroquinolone resistance may include reduced 36-kDa OMP production as well as GyrA and ParC mutations.
耐氟喹诺酮类产酸克雷伯菌的流行情况已在全球范围内报道。
我们从日本急性膀胱炎、无症状菌尿症或急性细菌性腹泻患者中分离出10株临床产酸克雷伯菌。在这10株分离菌中，纳入1株对氟喹诺酮敏感的分离菌作为对照。采用聚合酶链反应（PCR）和DNA测序方法对氟喹诺酮耐药性进行基因特征分析。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）测定外膜蛋白（OMP）谱。
在9株耐左氧氟沙星产酸克雷伯菌临床分离株中，喹诺酮耐药决定区的核苷酸序列显示出氨基酸突变，如GyrA中的Thr83Ile和Asp87Gly以及ParC中的Ser80Ile。两株产酸克雷伯菌分离株对氟喹诺酮的最低抑菌浓度高于其他耐氟喹诺酮分离株，显示出36-kDa OMP产生减少以及GyrA和ParC氨基酸突变的联合作用。
在临床产酸克雷伯菌分离株中，氟喹诺酮耐药的多种机制可能包括36-kDa OMP产生减少以及GyrA和ParC突变。
