Wang Gang, Song Guobin, Xu Yuanhong
Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, People's Republic of China.
Department of Clinical Laboratory, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China.
Infect Drug Resist. 2021 May 14;14:1823-1831. doi: 10.2147/IDR.S305280. eCollection 2021.
Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a novel method that can be used to identify pathogens and has potential applications in the detection of drug-resistant bacteria.
To evaluate the ability of a MALDI-TOF MS-based broth micro-dilution method in detecting the minimum inhibitory concentration (MIC) values of to ceftriaxone and imipenem.
Sixty strains of with different levels of resistance to carbapenems and cephalosporins were randomly collected. The 0.5 McFarland (Mc) concentration of the bacterial suspension was inoculated in cation-adjusted Mueller-Hinton broth (CAMHB) with a final cell turbidity of 5×10 CFU/mL. The broth was incubated with serial concentrations of antibiotics. After centrifuging the bacterial suspensions, the lysed cells were analyzed by MALDI-TOF MS to identify the growth-promoting or inhibitory effects on . The molecular mechanisms of resistance were investigated by PCR and DNA sequencing analysis.
The expression of known resistance genes ( and ) was detected in the 30 carbapenems-resistant strains. The agreement between the MIC values derived from the MALDI-TOF MS analysis and from the broth micro-dilution method was 61.7% for ceftriaxone and 71.7% for imipenem. According to the Clinical and Laboratory Standards Institute (CLSI) breakpoint of resistance to ceftriaxone and imipenem, the 60 isolates were accurately classified as resistant or susceptible isolates with 100% sensitivity and 100% specificity.
The transmission and infection of multidrug-resistant bacteria could be better managed and treated with the rapid identification of strains and antimicrobial susceptibility. A MALDI-TOF MS-based susceptibility test could be used to identify resistance of within a short time-frame. This approach could potentially be used as a supplementary antimicrobial susceptibility test that could be investigated on more bacterial species combined with different antibiotics.
基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）是一种可用于鉴定病原体的新方法，在耐药菌检测中具有潜在应用价值。
评估基于MALDI-TOF MS的肉汤微量稀释法检测肺炎克雷伯菌对头孢曲松和亚胺培南最低抑菌浓度（MIC）值的能力。
随机收集60株对碳青霉烯类和头孢菌素类具有不同耐药水平的肺炎克雷伯菌。将0.5麦氏（Mc）浓度的细菌悬液接种于阳离子调节的 Mueller-Hinton肉汤（CAMHB）中，最终细胞浊度为5×10⁵CFU/mL。肉汤与系列浓度的抗生素孵育。将细菌悬液离心后，用MALDI-TOF MS分析裂解后的细胞，以鉴定对肺炎克雷伯菌的生长促进或抑制作用。通过PCR和DNA测序分析研究耐药的分子机制。
在30株耐碳青霉烯类菌株中检测到已知耐药基因（blaNDM和blaKPC）的表达。MALDI-TOF MS分析得出的MIC值与肉汤微量稀释法得出的MIC值之间的一致性，头孢曲松为61.7%，亚胺培南为71.7%。根据临床和实验室标准协会（CLSI）对头孢曲松和亚胺培南的耐药断点，60株分离株被准确分类为耐药或敏感分离株，灵敏度和特异性均为100%。
通过快速鉴定菌株和抗菌药物敏感性，可更好地管理和治疗多重耐药菌的传播和感染。基于MALDI-TOF MS的药敏试验可在短时间内鉴定肺炎克雷伯菌的耐药性。这种方法有可能用作补充性抗菌药物敏感性试验，可结合不同抗生素对更多细菌种类进行研究。
