Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.
Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden; Department of Clinical Microbiology, Karolinska University Hospital, Huddinge, Sweden.
Anaerobe. 2019 Jun;57:59-62. doi: 10.1016/j.anaerobe.2019.03.014. Epub 2019 Mar 26.
Identification of anaerobic bacteria causing blood stream infections (BSI) is challenging. This study describes the epidemiology of anaerobic BSI at a tertiary care hospital and the performance of a rapid method for identification of anaerobic bacteria from blood cultures over three years, between June 2015 and June 2018. Short-term culturing is a low-cost user-friendly method and may be used for rapid identification of bacteria from positive blood cultures by matrix-associated laser desorption ionization time of flight (MALDI-TOF). Short-term culturing is performed after Gram staining on all positive blood culture bottles (BCBs) before 10:30 a.m. in our laboratory. Successful short-term cultures were defined as growth and reliable MALDI-TOF result in maximum 8 h after culture positivity. Data pertaining to unique anaerobic episodes and short-term cultures was collected retrospectively from our laboratory information system. Overall, during the three-year period, 692 unique anaerobic episodes (including Propionibacterium spp) were isolated. A total of 17 anaerobic bacterial genera were isolated in our laboratory, with 5 GNB genera and 12 GPB genera. The most prevalent bacteria were Bacteroides spp. 266/692 (38%), Propionibacterium spp. 128/692 (18%), Clostridium spp. 103/692 (15%), Fusobacterium spp. 34/692 (5%), and Actinomyces spp. 34/692 (5%). We performed short-term cultures on 270/564 (48%) clinically relevant episodes (excluding Propionibacterium spp) on chocolate agar plates. Growth within 8 h from culture positivity was detected in 33/270 (12%) short-term cultures. There were 22/33 (67%) gram negative (GNB) and 11/33 (33%) gram positive bacteria (GPB). Only two genera were identified: Bacteroides spp 22/33 (67%) and Clostridium spp 11/33 (33%). Thus, short-term culturing can function as a low-cost add-on to already existing protocols involving MALDI-TOF, where both GNB and GPB can be identified.
鉴定引起血流感染（BSI）的厌氧菌具有挑战性。本研究描述了一家三级护理医院的厌氧菌血流感染的流行病学，以及在 2015 年 6 月至 2018 年 6 月的三年内，使用一种从血培养中快速鉴定厌氧菌的快速方法的性能。短期培养是一种低成本、用户友好的方法，可通过基质辅助激光解吸电离飞行时间（MALDI-TOF）用于快速鉴定阳性血培养中的细菌。在我们的实验室中，所有上午 10:30 之前革兰氏染色阳性的血培养瓶（BCB）都进行短期培养。成功的短期培养被定义为培养阳性后 8 小时内生长和可靠的 MALDI-TOF 结果。从我们的实验室信息系统中回顾性收集了有关独特厌氧菌发作和短期培养的数据。总体而言，在三年期间，分离出 692 例独特的厌氧菌发作（包括丙酸杆菌属）。我们实验室共分离出 17 种厌氧菌属，其中 5 种为革兰氏阴性菌（GNB）属，12 种为革兰氏阳性菌（GPB）属。最常见的细菌是拟杆菌属 266/692（38%）、丙酸杆菌属 128/692（18%）、梭菌属 103/692（15%）、梭杆菌属 34/692（5%）和放线菌属 34/692（5%）。我们在巧克力琼脂平板上对 270/564 例（不包括丙酸杆菌属）有临床意义的发作进行了短期培养。在培养阳性后 8 小时内检测到生长的有 33/270（12%）例短期培养。其中 22/33（67%）为革兰氏阴性菌（GNB），11/33（33%）为革兰氏阳性菌（GPB）。仅鉴定出 2 个属：拟杆菌属 22/33（67%）和梭菌属 11/33（33%）。因此，短期培养可以作为一种低成本的附加物，与已经存在的 MALDI-TOF 协议一起使用，其中可以鉴定 GNB 和 GPB。
