Laboratory diagnosis of Talaromyces marneffei associated bloodstream infections
TANG Sishi1, LI Yan2, CHEN Zhixing1, DAI Zhongqiu1, AO Keping1, HE Chao1
1. Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu 610041,China;
2. Department of Laboratory Medicine, Xinjiang Production and Construction Corps First Division Hospital,Akesu 843000,China
Objective To establish a laboratory diagnostic pathway of talaromyces marneffei associated bloodstream infection so as to provide reference for the diagnosis and treatment of relateddiseases.Methods Peripheral blood samples were collected from the patients suspected with fungal bloodstream infection before whole blood cell count, smearing and microscopy were performed for these specimens. Blood specimens were cultured and detected with biphasic temperature culture when filamentous fungi were found in the smear of instrument alarmed-positive specimens. The suspected colonies were identified by morphology and Matrix-Assisted Laser Desorption/ Ionization Time of Flight (MALDI-TOF MS). Plasma (1,3)-β-D-glucan was determined by colorimetry. The clinical data of the patients was collected for statistical analysis.Results Twenty-four cases were included in this study, and the average age was 42.2 years old.The ratio of males to females was 7:1, and their underlying diseases were acquired immune deficiency syndrome. Among these patients, 8 (34.8%) had low white blood count and 20(87.0%) had decreased hemoglobin. All the 24 strains were identified as T. marneffei by morphology and MALDI-TOF MS. In one case (4.2%), specific morphology of T. marneffei was observed in the peripheral blood smear. Five(62.5%) of the eight patients were positive for plasma (1,3)-β-D-glucan. Among the 16 hospitalized patients, 10(62.5%)had respiratory symptoms, and 12 (75.0%) suffered secondary infections, whose median length of hospital stay was 12.0 days, and hospital mortality was 52.3%.Conclusions The laboratory diagnosis of T. marneffei associated bloodstream infections should be combined with peripheral blood cell count, blood culture, (1,3)-β-D-glucan test and clinical data.Patients who have poor immunityare more vulnerable to secondary infection and poor prognosis.
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