泰国东北部一位患者住所附近环境中类鼻疽伯克霍尔德菌分离株的流行情况及遗传多样性。
Prevalence and genetic diversity of Burkholderia pseudomallei isolates in the environment near a patient's residence in Northeast Thailand.
机构信息
Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand.
出版信息
PLoS Negl Trop Dis. 2019 Apr 19;13(4):e0007348. doi: 10.1371/journal.pntd.0007348. eCollection 2019 Apr.
BACKGROUND
Burkholderia pseudomallei is the causative agent of melioidosis, a severe infectious disease in tropical regions. It is necessary to understand the risk of acquiring this infection from the environment.
METHODOLOGY /PRINCIPAL FINDINGS: The prevalence, concentration and genetic diversity of B. pseudomallei isolates collected from two sites in Buriram, Northeast Thailand were investigated. Forty-four environmental samples (18 from soil, 14 from rice rhizosphere, and 12 from water) were collected; of those 44 samples, 19 were collected from near a patient's residence and 25 from suspected exposure sites and compared with 10 clinical isolates of the patient. Quantitative culture was performed, and B. pseudomallei was identified using the latex agglutination test and matrix-laser absorption ionisation mass spectrometry. Genotyping was performed in 162 colonies from clinical (N = 10) and environmental samples (N = 152) using pulse-field gel electrophoresis (PFGE) followed by multi-locus sequence typing (MLST) of the clinical strain. B. pseudomallei was detected in 11 of the 44 environmental samples (1 from soil, 4 from rice rhizosphere, and 6 from water). The bacterial count in the positive soil sample was 115 CFU/g. The mean concentrations ± SDs of B. pseudomallei in the positive water and rhizosphere samples were 5.1 ± 5.5 CFU/ml and 80 ± 49 CFU/g, respectively. Six water samples with positive results were collected from a pond and water sources for drinking and daily use. All colonies isolated from the patient shared the same PFGE type (PT) indicating monoclonal infection of ST99. Although the 152 colonies from environmental isolates exhibited 25 PTs, none were identical to the patient's isolates. PT5 and PT7 were most common genotype among the environmental samples.
CONCLUSIONS/SIGNIFICANCE: Diverse genotypes of B. pseudomallei were prevalent in the environment. However, the patient may have been infected with a low-density genotype. Intervention strategies for preventing B. pseudomallei infection are required.
背景
类鼻疽伯克霍尔德菌是类鼻疽病的病原体，这是一种在热带地区发生的严重传染病。有必要了解从环境中获得这种感染的风险。
方法/主要发现：本研究调查了在泰国东北部武里南的两个地点采集的类鼻疽伯克霍尔德菌分离株的流行率、浓度和遗传多样性。采集了 44 份环境样本（18 份来自土壤，14 份来自水稻根际，12 份来自水）；其中 44 份样本来自患者住所附近，25 份来自疑似暴露地点，并与患者的 10 份临床分离株进行了比较。进行了定量培养，并使用乳胶凝集试验和基质激光吸收离子化质谱法鉴定类鼻疽伯克霍尔德菌。使用脉冲场凝胶电泳（PFGE）对来自临床（N=10）和环境样本（N=152）的 162 个菌落进行基因分型，然后对临床菌株进行多位点序列分型（MLST）。在 44 份环境样本中的 11 份中检测到类鼻疽伯克霍尔德菌（1 份来自土壤，4 份来自水稻根际，6 份来自水）。阳性土壤样本中的细菌数为 115 CFU/g。阳性水样和根际样本中类鼻疽伯克霍尔德菌的平均浓度（平均值±标准差）分别为 5.1±5.5 CFU/ml 和 80±49 CFU/g。从池塘和饮用水源采集的 6 份阳性水样。从患者身上分离出的所有菌落均具有相同的脉冲场凝胶电泳类型（PT），表明 ST99 的单克隆感染。尽管从环境分离株中分离出的 152 个菌落显示出 25 种 PT，但没有一种与患者的分离株相同。PT5 和 PT7 是环境样本中最常见的基因型。
结论/意义：环境中普遍存在多种基因型的类鼻疽伯克霍尔德菌。然而，患者可能感染了低密度基因型。需要采取预防类鼻疽伯克霍尔德菌感染的干预策略。
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