Hansotia J B, Agarwal V, Pathak A A, Saoji A M
Department of Microbiology, Government Medical College, Nagpur.
Indian J Med Res. 1997 Apr;105:158-61.
Out of 66 clinical isolates of Klebsiella pneumoniae, 17 showed resistance or decreased susceptibility to third generation cephalosporins (17 to cefotaxime, 16 to ceftriaxone, and 9 to ceftazidime) while the remaining 49 were sensitive by the disc diffusion method. The minimum inhibitory concentrations (MICs) of the third generation cephalosporins (3GC) for the strains ranged from 2-128 micrograms/ml by agar dilution method. Their sensitive phenotypes had zone diameters smaller (mean difference 3. 1 mm for ceftriaxone, and 6.5 mm for ceftazidime), and MICs > 10 fold higher than the corresponding values in the fully sensitive isolates. Resistance to cefotaxime was transferred to recipient Escherichia coli K12 strain in 15 isolates. All the resistant isolates were sensitive to imipenem but were variably sensitive to aminoglycosides, and quinolones. In all 17 resistant isolates extended spectrum beta-lactamase (ES beta L) was detected. The sensitivity testing systems may fail to recognise the potential ES beta L mediated resistance to 3GC. Hence ES beta L detection should be routinely undertaken.
在66株肺炎克雷伯菌临床分离株中，17株对第三代头孢菌素表现出耐药或敏感性降低（对头孢噻肟耐药17株，对头孢曲松耐药16株，对头孢他啶耐药9株），而其余49株通过纸片扩散法检测为敏感。通过琼脂稀释法测定，第三代头孢菌素（3GC）对这些菌株的最低抑菌浓度（MIC）范围为2至128微克/毫升。它们的敏感表型抑菌圈直径较小（头孢曲松平均差异3.1毫米，头孢他啶平均差异6.5毫米），且MIC比完全敏感分离株的相应值高10倍以上。15株分离株中对头孢噻肟的耐药性转移至受体大肠杆菌K12菌株。所有耐药分离株对亚胺培南敏感，但对氨基糖苷类和喹诺酮类药物的敏感性各不相同。在所有17株耐药分离株中均检测到超广谱β-内酰胺酶（ESβL）。敏感性检测系统可能无法识别潜在的ESβL介导的对3GC的耐药性。因此，应常规进行ESβL检测。
