Division of Microbiology, Department of Pathology, Sidra Medicine, Doha, Qatar.
Weill Cornell Medical College in Qatar, Doha, Qatar.
Microbiol Spectr. 2021 Dec 22;9(3):e0190521. doi: 10.1128/spectrum.01905-21.
The performance and early therapeutic impact of direct identification by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF; DIMT) on pediatric blood culture bottles using in-house-developed methods to obtain microbial pellets for spectrometric analysis have seldom been studied. During a 2-year period (June 2018 to May 2020), DIMT was performed on broths from positive pediatric blood culture bottles using an in-house-developed method. Organism identifications with a score of ≥1.6 were notified to treating clinicians. Therapeutic modifications that occurred after the communication of DIMT were reviewed through the electronic medical records. DIMT was performed on 530 pediatric positive blood culture bottles. Among 505 monomicrobial bottles, identifications from 298 (97.7%) deemed as bloodstream infections (BSI) and 189 (94.5%) as contaminations had DIMT notified to clinicians. All identifications were correct except for one Streptococcus mitis incorrectly reported as Streptococcus pneumoniae. Therapy modifications resulting from DIMT occurred in 27 (8.3%) patients with BSI. Deescalation from effective or ineffective broad-spectrum regimens occurred mainly in Enterococcus faecalis bacteremia, whereas appropriate escalation from an ineffective regimen with narrower spectrum occurred mainly in bacteremia caused by AmpC-β-lactamase-producing . Escalation therapy was instituted significantly faster than deescalation therapy (median time, 0.75 versus 10.5 h [0.01]). DIMT also enabled clinicians to confirm contamination in nearly one-half of patients with contaminated blood cultures. Our DIMT method applied to positive pediatric blood culture bottles demonstrated reliable performance for the rapid identification of pathogens. Our DIMT approach allowed therapeutic optimization in BSI, especially involving microorganisms with intrinsic antibiotic resistance, and was helpful in the early identification of likely contaminants. We demonstrate the performance and early impact on the antimicrobial management of bloodstream infections of an inexpensive, in-house preparation method for direct identification of bloodstream pathogens in pediatric blood culture bottles by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry.
利用内部开发的方法从阳性儿科血培养瓶的肉汤中进行基质辅助激光解吸电离飞行时间质谱（MALDI-TOF；DIMT）直接鉴定，很少研究其对儿科血培养瓶的性能和早期治疗影响。在 2 年期间（2018 年 6 月至 2020 年 5 月），使用内部开发的方法对阳性儿科血培养瓶的肉汤进行 DIMT。将得分≥1.6 的生物体鉴定结果通知给治疗临床医生。通过电子病历回顾了 DIMT 沟通后发生的治疗修改。对 530 个儿科阳性血培养瓶进行了 DIMT。在 505 个单瓶中，298 个（97.7%）被认为是血流感染（BSI）和 189 个（94.5%）被认为是污染的鉴定结果通知了临床医生。除了一个错误地报告为肺炎链球菌的米氏链球菌外，所有鉴定结果都是正确的。BSI 患者中有 27 例（8.3%）因 DIMT 发生治疗改变。从有效或无效的广谱方案降级主要发生在粪肠球菌菌血症中，而从无效方案升级为更窄谱主要发生在产 AmpC-β-内酰胺酶的细菌引起的菌血症中。升级治疗的启动速度明显快于降级治疗（中位数时间，0.75 与 10.5 h[0.01]）。DIMT 还使临床医生能够确认近一半污染血培养患者的污染情况。我们应用于阳性儿科血培养瓶的 DIMT 方法对病原体的快速鉴定具有可靠的性能。我们的 DIMT 方法允许在 BSI 中进行治疗优化，特别是涉及具有内在抗生素耐药性的微生物，并且有助于早期识别可能的污染物。我们展示了一种廉价的内部制备方法，用于通过基质辅助激光解吸/电离飞行时间质谱法直接鉴定儿科血培养瓶中的血流病原体，该方法在儿科血培养瓶中对血流感染的抗菌管理的性能和早期影响。
