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    Home > Active Ingredient News > Infection > G test, GM test combined with inflammation indicators lead a new trend in the detection of fungi and bacteria

    G test, GM test combined with inflammation indicators lead a new trend in the detection of fungi and bacteria

    • Last Update: 2021-05-03
    • Source: Internet
    • Author: User
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    At present, with the continuous upgrading of medical diagnosis technology, the thorny clinical treatment problem of infectious diseases is gradually being addressed.
    Infection is a common and frequently-occurring disease in clinic.
    It can occur in any part of the human body.
    It may cause inflammation and complications of multiple organs of the patient, such as pneumonia and sepsis.
    Serious infections can even be life-threatening.
    Detection of infection-related biomarkers can assist in the diagnosis of infectious diseases, and play an important role in guiding the use of antibiotics and judging the prognosis of patients.
    Many studies have shown that the combined detection of multiple biological indicators such as BDG, GM, PCT, CRP, IL-6 has important clinical value in the early differential diagnosis of fungal and bacterial bloodstream infections [1].

    Knowing this, what are the several test indicators mentioned in the literature? What is the clinical significance of biomarkers for differential diagnosis? Let us find out together!

    65pt;text-indent:2em;"> Infectious diseases are often not specific due to their symptoms, signs and imaging manifestations, and some non-infectious diseases also have some clinical manifestations that resemble infections, and misdiagnosis is very easy to occur in the diagnosis of infectious diseases.
    The detection of infection-related biomarkers as an auxiliary diagnostic measure has important reference significance for differential diagnosis [2].
    In addition to the diagnosis of infectious diseases, certain biomarkers are also of great help in determining the prognosis of patients and determining the course of anti-infection treatment, and can also help to distinguish the pathogens that cause infection (bacteria, fungi, tuberculosis, viruses) to a certain extent.
    ).

    Clinical significance of infection-related biomarkers

    Clinical significance of infection-related biomarkers

    G test and GM test are common clinical detection methods for fungi.
    The detection method is mature, specific and sensitive.
    It is suitable for the detection of markers (1, 3)-β-D glucan and Aspergillus galactomannan.
    The detection method has become the recommended detection method in many consensus guidelines such as CLSI M100, "Diagnostic Criteria and Principles of Treatment of Invasive Mycosis in Patients with Hematological Diseases/Malignant Tumors" (Sixth Revised Edition).

    PCT, CRP and IL-6 are currently commonly used clinical indicators for systemic inflammatory response.
    Among them, PCT and CRP are in the diagnostic criteria recommended by the American Association of Chest Physicians and the American College of Critical Care Medicine (ACCP/SCCM) and the 2001 International Sepsis Symptom Definition Conference’s criteria for sepsis are listed as diagnostic elements [3].

    1.
    (1, 3)-β-D glucan (BDG): BDG is widely present in the cell wall of fungi.
    When the fungus infects human blood or deep tissues, under the phagocytosis and digestion of phagocytes, BDG is removed from the cell wall.
    It is released in the blood, thereby increasing its content in blood and other body fluids.
    BDG is an effective biomarker for early diagnosis of invasive fungal infections.
    Studies have shown that serum BDG levels higher than normal are earlier than clinical symptoms and microbiological evidence [4].

    2.
    Aspergillus galactomannan (GM): GM is mainly present in the cell walls of Aspergillus and Penicillium.
    For patients with deep Aspergillus infection, the result of serum GM test is higher than the imaging evidence [4].
    The dynamic monitoring of the GM test can be used as an effective means to evaluate the efficacy and prognosis of anti-Aspergillus treatment in patients with severe infections.

    3.
    Procalcitonin (PCT): PCT is a protein, and its level in plasma increases when severe bacterial, fungal, parasitic infections, sepsis and multiple organ failure occur.
    PCT will not increase during autoimmunity, allergies and viral infections.
    PCT reflects the active degree of systemic inflammation.
    Factors affecting PCT levels include the size and type of the infected organ, the type of bacteria, the degree of inflammation, and the status of the immune response.
    In addition, PCT can only be measured 1 to 4 days after large-scale surgery in a small number of patients [3].

    4.
    C-reactive protein (CRP): CRP is a traditional infection biomarker.
    Its serum level is closely related to infection and inflammation.
    It is not affected by anti-inflammatory and immune agents when reflecting inflammation.
    IL-6 is an important cytokine expressed by the innate immune system in the initial response to injury and infection.
    It can promote the production of CRP in the liver to assist in the early diagnosis of acute infections.
    The two are less specific than PCT in the identification of infection types [4 ].

    5.
    Interleukin-6 (IL-6): IL-6 is a lymphokine produced by activated T cells and fibroblasts.
    It can make B cell precursors become antibody-producing cells; in conjunction with colony stimulating factors, it can promote the growth and differentiation of primitive bone marrow-derived cells, enhance the lysis function of natural killer cells, and improve the maturation, activation, proliferation and immune regulation of immune cells.
    They play an important role in a series of processes, and they also participate in a variety of physiological and pathological reactions of the body.

    The G test is suitable for the detection of pan-fungal infections, and the GM test is the main clinical detection method for Aspergillus.
    The combined application of PCT, CRP, and IL-6 can quickly and accurately provide clinical evidence for the early diagnosis of sepsis.
    There are reports in the literature that PCT has a certain role in the early diagnosis of bacterial bloodstream infections and the identification of bloodstream infections caused by different bacterial species.
    Clinical application value [3].
    Relevant studies have shown that sepsis markers such as PCT and BDG detection can help clinicians diagnose or rule out deep fungal infections in the early stage [5], which is convenient for clinicians to judge and evaluate invasive fungal infections.

    In clinical diagnosis, the combined detection of multiple indicators can effectively improve the sensitivity, specificity, negative and positive predictive values ​​of fungal and bacterial infections and other important indicators.

    In January 2020, Guo Jingjing et al.
    [4] published literature affirmed the diagnostic value of (1, 3)-β-D glucan, galactomannan combined with procalcitonin in the diagnosis of invasive fungal infections.
    This study reviews 447 hospitalized patients with high-risk IFI factors were included, and the serum levels of BDG, GM and PCT in the patients were detected, and the combined detection of the three was evaluated for the early diagnosis value of IFI.

    The results of the study of various indicators are shown in the figure.
    The sensitivity of the combined detection of G, GM, and PCT is 94.
    12%, the negative predictive value is 98.
    81%, and the Youden index is 0.
    57.
    The sensitivity of the three combined tests is higher than that of the G test, GM test, PCT single test and G/GM combined test, and the specificity is lower than that of each test, and the difference is statistically significant (all P values ​​<0.
    05).
    The combined detection of G, GM, and PCT can significantly improve the sensitivity of IFI detection.
    And it is of great value in the diagnosis and exclusion of IFI, thereby reducing the false positive rate and false negative rate, and providing a certain basis for the early diagnosis of IFI .

    In January 2021, Miao Qiang et al.
    [1] pointed out in the article that the levels of PCT, CRP, IL-6, and BDG can be used as reference indicators to distinguish fungal and bacterial bloodstream infections, and the differential diagnosis value of PCT and BDG is higher[1 ].
    The combined detection of four indicators has important clinical value in the early differential diagnosis of fungal and bacterial bloodstream infections.

    The literature included 124 hospitalized patients with high-risk IFI factors, and compared the levels of PCT, CRP, IL-6, BDG and GM test indicators in patients with bacterial and fungal infections, and used receiver operating curve (ROC) to evaluate each indicator individually and in combination The value of testing for the diagnosis of fungal bloodstream infections.

    The levels of serum PCT, CRP and IL-6 in the fungus group were significantly lower than those in the bacteria group, and the difference was statistically significant (all P <0.
    001).
    The level of BDG in the fungal group was significantly higher than that in the bacterial group, and the difference was statistically significant (P <0.
    001) [1].
    The combined detection of multiple indicators in patients has certain clinical significance for the early differentiation of fungal and bacterial bloodstream infections.

    7pt;text-indent:2em;"> The ROC curve of individual and combined detection of each index to identify fungal bloodstream infections shows that the area under the ROC curve of PCT, CRP, IL-6 and BDG are 0.
    859, 0.
    718, 0.
    800 and 0.
    843, which are useful for the auxiliary diagnosis of fungal bloodstream infections.
    Certain value (P <0.
    05).
    It is worth noting that the combined AUC of the four indicators is higher than that of a single test, and the sensitivity, specificity, negative and positive predictive values ​​are all improved, indicating that PCT and other inflammatory indicators combined with BDG testing can be used in the early differential diagnosis of fungal and bacterial bloodstream infections.
    There is a certain clinical value [1].

    In addition, Jiang Yuehong et al.
    [6] pointed out that the percentage of (1,3)-β-D-glucan and CRP in plasma can reflect the presence of fungal infection, while the level of plasma (1,3)-β-D-glucan can reflect blood In severe cases of influenza infection, the PCT level can be preliminarily inferred whether it is a non-Candida albicans infection or a Candida albicans infection.

    It should be pointed out that no biomarker is absolutely sensitive and absolutely specific, and the change of a certain biomarker cannot be used to diagnose the disease.
    It can only be done by combining and referring to the clinical manifestation of the patient and the results of other laboratory tests.
    Make the correct judgment [2].

    * The combined detection of multiple indicators has broadened new ideas for the diagnosis of fungal and bacterial infections.
    Fully automatic detection products help the diagnosis business to enter the fast lane.

    The comprehensive fungus and bacteria detection program makes the experiment more accurate and efficient.
    The IGL series of fungal and bacterial dynamic detectors innovatively realize (1, 3)-β-D glucan and gram-negative bacteria lipopolysaccharides are automatically detected.
    FACIS automatic chemiluminescence enzyme immunoassay instrument has achieved the GM experiment.
    Fully automatic detection, it is expected that a fully automatic intelligent detection platform covering multiple biological markers will be built, and the joint detection of multiple indicators will be perfectly realized, laying a solid foundation for the arrival of the intelligent era of fungus and bacteria detection.

    references:

    references:

    [1] Miao Qiang, Xu Xiaohua, Wei Bin, Bai Yangjuan, Zhang Junlong, Cai Bei, Niu Qian.
    Detection of inflammatory indicators combined with (1,3)-β-D glucan in the early differential diagnosis of fungal and bacterial bloodstream infections The value of [J].
    The Journal of Practical Medicine,2021,37(01):96-100.

    [1] Miao Qiang, Xu Xiaohua, Wei Bin, Bai Yangjuan, Zhang Junlong, Cai Bei, Niu Qian.
    Detection of inflammatory indicators combined with (1,3)-β-D glucan in the early differential diagnosis of fungal and bacterial bloodstream infections The value of [J].
    The Journal of Practical Medicine,2021,37(01):96-100.

    [2] Liu Youning, Xie Lixin.
    Expert consensus on interpretation of clinical significance of infection-related biomarkers [J].
    Chinese Journal of Tuberculosis and Respiratory, 2017, 40(04): 243-257.

    [2] Liu Youning, Xie Lixin.
    Expert consensus on interpretation of clinical significance of infection-related biomarkers [J].
    Chinese Journal of Tuberculosis and Respiratory, 2017, 40(04): 243-257.

    [3] Zhu Meiying, Cao Ehong.
    Detection and application of procalcitonin-interpretation of "Expert consensus on interpretation of clinical significance of infection-related biomarkers" [J].
    Shanghai Medicine, 2018, 39(01): 14-18.

    [3] Zhu Meiying, Cao Ehong.
    Detection and application of procalcitonin-interpretation of "Expert consensus on interpretation of clinical significance of infection-related biomarkers" [J].
    Shanghai Medicine, 2018, 39(01): 14-18.

    [4] Guo Jingjing, Li Qinfeng, Wu Haihua, Ding Chen, Shi Fangyu.
    The diagnostic value of (1,3)-β-D glucan, galactomannan combined with procalcitonin in the diagnosis of invasive fungal infections[J].
    International Journal of Immunology, 2020(01): 31-32-33-34-35-36.

    [4] Guo Jingjing, Li Qinfeng, Wu Haihua, Ding Chen, Shi Fangyu.
    The diagnostic value of (1,3)-β-D glucan, galactomannan combined with procalcitonin in the diagnosis of invasive fungal infections[J].
    International Journal of Immunology, 2020(01): 31-32-33-34-35-36.

    [5] MAERTENS J, THEUNISSEN K, VERBEKEN E, et al.
    Pro-spective clinical evaluation of lower cut ⁃ offs for galactomannan detection in adult neutropenic cancer patients and haematologi-cal stem cell transplant recipients[J].
    Br J Haematol, 2004 , 126(6): 852-860.

    [5] MAERTENS J, THEUNISSEN K, VERBEKEN E, et al.
    Pro-spective clinical evaluation of lower cut ⁃ offs for galactomannan detection in adult neutropenic cancer patients and haematologi-cal stem cell transplant recipients[J].
    Br J Haematol, 2004 , 126(6): 852-860.

    [6] Jiang Yuehong, Li Xiaolin, Sun Jian, Yan Li, Wang Tong, You Yuhong, Jin Wei, Wang Feng, Zhang Chao.
    Effects of plasma (1,3)-β-D glucan and C-reactive protein on fungal activity Evaluation of bloodstream infection[J].
    Chinese Medical Science,2019,9(03):9-12.

    [6] Jiang Yuehong, Li Xiaolin, Sun Jian, Yan Li, Wang Tong, You Yuhong, Jin Wei, Wang Feng, Zhang Chao.
    Effects of plasma (1,3)-β-D glucan and C-reactive protein on fungal activity Evaluation of bloodstream infection[J].
    Chinese Medical Science,2019,9(03):9-12.
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