In the Lao People’s Democratic Republic (Laos), rickettsial infections, including scrub and murine typhus, account for a significant burden of fevers. The Mahosot Hospital Microbiology Laboratory in Vientiane, Laos, routinely performs rickettsial isolation from hospitalized patients with suspected rickettsioses using mammalian cell culture systems. We review the clinical and laboratory factors associated with successful Orientia tsutsugamushi and Rickettsia typhi isolations from this laboratory over a period of 6 years between 2008 and 2014. The overall isolation success was 7.9% for all samples submitted and 17.3% for samples for which the patient had a positive O. tsutsugamushi or R. typhi rapid diagnostic test (RDT), serology, or PCR. The frequency of successful isolation was highest for samples submitted in November, at the end of the wet season (28.3%). A longer median duration of reported illness, a positive result for a concurrent Orientia or Rickettsia spp. quantitative PCR, and the use of antibiotics by the patient in the week before admission were significantly associated with isolation success (P < 0.05). Buffy coat inoculation and a shorter interval between sample collection and inoculation in the laboratory were associated with a higher frequency of isolation (both P < 0.05). This frequency was highest if cell culture inoculation occurred on the same day as blood sample collection. Factors related to the initial rickettsial bacterial concentration are likely the main contributors to isolation success. However, modifiable factors do contribute to the rickettsial isolation success, especially delays in inoculating patient samples into culture.

中文翻译：

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通过哺乳动物细胞培养从人血中分离出tsu虫和东方伤寒立克次体：老挝人民民主共和国的3,227个样本和结果的描述性系列

在老挝人民民主共和国（老挝），病感染（包括灌木和鼠伤寒）构成了严重的发烧负担。老挝万象的Mahosot医院微生物学实验室通常使用哺乳动物细胞培养系统对住院的疑似立克次体病患者进行立克特体隔离。我们回顾了在2008年至2014年之间的6年中，从该实验室成功分离出Or虫东方定向虫和立克次体伤寒杆菌的临床和实验室因素。总隔离成功率为所有提交的样本为7.9％，患者的样本为17.3％O虫或伤寒沙门氏菌阳性快速诊断测试（RDT），血清学或PCR。在雨季结束时，11月提交的样品成功隔离的频率最高（28.3％）。所报告疾病的中位时间更长，同时发生的Orientia或立克次体属阳性。定量PCR和患者入院前一周使用抗生素与隔离成功率显着相关（P <0.05）。血沉棕黄层的接种以及实验室中样品收集和接种之间的间隔时间较短，与较高的分离频率相关（均P<0.05）。如果在采集血样的同一天进行细胞培养接种，则该频率最高。与最初的立克次氏菌浓度有关的因素可能是隔离成功的主要因素。但是，可修改因素的确有助于立氏分离成功，尤其是在将患者样品接种至培养物中时出现延迟。