Discrepant susceptibility to gentamicin despite amikacin resistance in Klebsiella pneumoniae by VITEK 2 represents false susceptibility associated with the armA 16S rRNA methylase gene

作者：Ko Jae Hoon; Baek Jin Yang; Peck Kyong Ran^*; Cho Sun Young; Ha Young Eun; Kim So Hyun; Huh Hee Jae; Lee Nam Yong; Kang Cheol In; Chung Doo Ryeon; Song Jae Hoon

来源：Journal of Medical Microbiology, 2017, 66(10): 1448-1450.

DOI：10.1099/jmm.0.000583

Because we experienced gentamicin failure in Klebsiella pneumoniae bacteraemia that was susceptible to gentamicin despite amikacin resistance, as determined by VITEK 2, we evaluated the true susceptibility and mechanism of resistance. We screened 2818 K. pneumoniae isolates during a 1-year period at a university hospital and reviewed anti-microbial susceptibility reports using the VITEK 2 system. The minimum inhibitory concentration was substantiated by broth microdilution (BMD), and the presence of 16S rRNA methylase genes and aminoglycoside-modifying enzymes was also investigated. A total of 131 amikacin-resistant isolates from 19 patients were gentamicin non-resistant according to the VITEK 2 system. Among these, we were able to collect isolates from 12 patients (63.2 %), and a single isolate from each patient was tested. Eleven of the gentamicin non-resistant isolates (91.7 %) showed high-level resistance to both amikacin and gentamicin by BMD in association with the armA gene. Gentamicin is not an adequate treatment option for amikacinresistant K. pneumoniae, even if VITEK 2 reports susceptibility.

• 出版日期2017-10