沙雷氏 Actinobaculum - 侵袭性病原体还是无辜旁观者？一项回顾性观察研究。
Actinobaculum schaalii - invasive pathogen or innocent bystander? A retrospective observational study.
机构信息
Division of Infectious Diseases and Hospital Epidemiology, University Hospital, Basel, Switzerland.
出版信息
BMC Infect Dis. 2011 Oct 26;11:289. doi: 10.1186/1471-2334-11-289.
BACKGROUND
Actinobaculum schaalii is a Gram-positive, facultative anaerobic coccoid rod, classified as a new genus in 1997. It grows slowly and therefore is easily overgrown by other pathogens, which are often found concomitantly. Since 1999, Actinobaculum schaalii is routinely investigated at our hospital, whenever its presence is suspected due to the detection of minute grey colonies on blood agar plates and negative reactions for catalase. The objective of this study was to determine the clinical significance of Actinobaculum schaalii, identified in our microbiology laboratory over the last 11 years.
METHODS
All consecutive isolates with Actinobaculum schaalii were obtained from the computerized database of the clinical microbiology laboratory and patients whose cultures from any body site yielded this pathogen were analyzed. Observation of tiny colonies of Gram-positive, catalase-negative coccoid rods triggered molecular identification based on 16S rRNA gene sequencing.
RESULTS
40 isolates were obtained from 27 patients during the last 11 years. The patient's median age was 81 (19-101) years, 25 (92.6%) had underlying diseases and 12 (44.4%) had a genitourinary tract pathology. Actinobaculum schaalii was isolated in 12 urine cultures, 21 blood cultures, and 7 deep tissue biopsies. Twenty-five (62.5%) specimens were monobacterial, the remaining 15 (37.5%) were polybacterial 7/7 deep tissue samples (three bloodcultures and five urine cultures). Recovery from urine was interpreted as colonization in 5 (18.6%) cases (41.6% of all urine samples). Six (22.2%) suffered from urinary tract infections, six (22.2%) from abscesses (skin, intraabdominal, genitourinary tract, and surgical site infections) and 10 (37.0%) from bacteremia.
CONCLUSIONS
In this largest case series so far, detection of Actinobaculum schaalii was associated with an infection--primarily sepsis and abscesses--in 81.5% of our patients. Since this pathogen is frequently part of polymicrobial cultures (42.5%) it is often overlooked or considered a contaminant. Detection of Actinobaculum schaalii in clinical isolates mainly reflects infection indicating that this Gram-positive rod is not an innocent bystander.
背景
沙雷氏 Actinobaculum 是一种革兰阳性、兼性厌氧球菌棒状菌，于 1997 年被分类为一个新属。它生长缓慢，因此很容易被其他同时存在的病原体所覆盖。自 1999 年以来，每当在血琼脂平板上发现微小的灰色菌落且过氧化氢酶反应为阴性时，我们医院就会常规检测 Actinobaculum schaalii。本研究的目的是确定过去 11 年来在我们微生物实验室中鉴定的 Actinobaculum schaalii 的临床意义。
方法
从临床微生物实验室的计算机数据库中获取所有连续分离的 Actinobaculum schaalii 菌株，并对从任何部位培养物中分离出该病原体的患者进行分析。观察到革兰阳性、过氧化氢酶阴性球菌的微小菌落，触发基于 16S rRNA 基因测序的分子鉴定。
结果
在过去 11 年中，从 27 名患者中获得了 40 株分离株。患者的中位年龄为 81（19-101）岁，25 名（92.6%）有基础疾病，12 名（44.4%）有泌尿生殖道疾病。Actinobaculum schaalii 分离自 12 份尿液培养物、21 份血培养物和 7 份深部组织活检。25 份（62.5%）标本为单菌，其余 15 份（37.5%）为多菌，7 份（7/7 份）深部组织样本均为多菌（3 份血培养物和 5 份尿液培养物）。5 例（18.6%）尿液标本的分离物被解释为定植（占所有尿液标本的 41.6%）。6 例（22.2%）发生尿路感染，6 例（22.2%）发生脓肿（皮肤、腹腔、泌尿生殖道和手术部位感染），10 例（37.0%）发生菌血症。
结论
在迄今为止最大的病例系列研究中，在我们的患者中，81.5%的 Actinobaculum schaalii 检测与感染有关，主要是败血症和脓肿。由于该病原体经常是多微生物培养物的一部分（42.5%），因此经常被忽视或被认为是污染物。在临床分离物中检测到 Actinobaculum schaalii 主要反映了感染，表明这种革兰阳性杆菌不是无辜的旁观者。
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