
Advantages of Liquid Culture Method for Mycobacterium tuberculosis
2025-06-13
Mycobacterium tuberculosis is an obligate aerobic bacterium with high nutritional requirements. Its optimal pH range is 6.5–6.8, and it grows slowly, requiring nutrient-rich media for initial isolation. The commonly used Löwenstein-Jensen (LJ) solid medium contains egg yolk, glycerol, potato, inorganic salts, and malachite green. Malachite green inhibits the growth of contaminating bacteria, facilitating isolation and prolonged culture. The egg yolk provides lipid growth factors that stimulate bacterial growth. Depending on the inoculum size, colonies typically appear in 2–4 weeks. On solid media, colonies appear as dry, granular, raised, rough, and cauliflower-like with a grayish-yellow-white color. In liquid media, a thick, wrinkled pellicle forms at the surface while the medium remains clear. Adding Tween 80 to the medium promotes uniform dispersed growth, usually within 1–2 weeks.
Liquid culture yields a several-fold higher positivity rate than solid culture for clinical specimens. The bacteria stain red with acid-fast staining and exhibit strong resistance to drying and acids. They are prone to developing drug resistance and L-form variants. M. tuberculosis appears as slender, slightly curved bacilli, occurring singly or in branching arrangements, with no spores or flagella but possessing fimbriae. Traditional detection methods are time-consuming (up to 8 weeks) and have low positivity rates (≤20%), causing significant delays in diagnosis and treatment, highlighting the need for improvement.
Liquid culture, due to its optimized detection principle, offers unparalleled advantages over solid culture. As the gold standard in methodology, it provides unmatched reliability. M. tuberculosis is resistant to acids and alkalis, highly resistant to drying, but sensitive to ethanol, moist heat, and ultraviolet radiation. It can infect various tissues and organs, particularly the lungs, causing tuberculosis and severely impacting human health. Diagnosing tuberculosis typically requires culturing M. tuberculosis to confirm clinical cases and guide treatment.
Liquid culture is generally regarded as a rapid method for mycobacterial growth, significantly shortening the time required for clinical diagnosis. It is more sensitive than solid culture, with a higher detection rate. The liquid medium provides more abundant nutrients, promoting faster growth—positive results can be obtained in 1–2 weeks, much sooner than with solid culture. If no growth is observed after 6 weeks, a negative report can be issued, greatly reducing waiting time.
The BACTEC™ MGIT™ (Mycobacteria Growth Indicator Tube) system, an automated mycobacterial culture monitoring instrument, is compatible with liquid culture tubes, offering high detection rates and significantly improving clinical testing efficiency.
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Why Does Plasma Require Rapid Freezing at Low Temperatures?
2025-06-03
Blood transfusion is a common medical treatment today. In cases of anemia, massive bleeding, or when other treatments prove ineffective, clinical practitioners typically resort to blood transfusion. While the most familiar form involves the infusion of red blood cell suspensions, transfusion in a broader sense also includes plasma, cryoprecipitate, platelets, leukocytes, and other blood components.
Storage Conditions for Blood Products
Today, we’ll explore the storage requirements for different blood products. The most well-known, red blood cell suspensions, must be stored at 4–6°C, while platelets require agitated storage. Notably, plasma and cryoprecipitate demand ultra-low temperatures of -25°C or below. But why?
To understand this, we must first examine the properties of plasma.
Characteristics of Plasma
Plasma serves as the transport medium for blood cells, carrying essential nutrients, metabolic waste, and other vital substances. Functionally similar to the extracellular matrix of connective tissue, plasma is a pale yellow liquid (due to bilirubin content) and a major component of blood.
Composition of Plasma:90–92% water,10% solutes, primarily plasma proteins, along with electrolytes, nutrients (e.g., glucose, amino acids), enzymes, hormones, cholesterol, and other critical components.
Plasma proteins, classified into albumin, globulins, and fibrinogen, are the most important structural proteins in blood.
Plasma acts as the extracellular matrix of blood, with a highly complex composition including proteins, lipids, inorganic salts, sugars, amino acids, metabolic waste, and large amounts of water.
Why Low-Temperature Freezing?
Given its composition, some plasma components are unstable. Immediate freezing after collection:
Extends shelf life (prevents degradation of proteins like clotting factors).
Preserves labile components, ensuring transfusion efficacy.
Baso’s Plate Plasma Rapid Freezer
Baso’s plate-type plasma rapid freezer achieves a core temperature of -30°C within 30 minutes, ensuring uniform freezing. Key features:Equipped with a Bitzer two-stage compressor, max input power of 4 kW, reaching evaporation temperatures as low as -60°C.
Incorporates two patented technologies:
Simulated Plasma QC Bag (Patent Technology)
Uses a thermal mass ratio identical to real plasma.
A temperature probe inserted into the core of the simulated bag collects real-time data, ensuring accurate monitoring of freezing conditions.
Flexible Contact Technology (Patent Technology)
A specially designed flexible pad accommodates variations in plasma bag thickness, eliminating uneven freezing.
Experimental data confirm a 20%+ improvement in freezing efficiency.
This advanced freezing method ensures higher-quality plasma for transfusions, maintaining the integrity of critical components. For medical professionals, precise freezing is essential for optimal patient outcomes.
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Baso team participated in two academic conferences in April
2025-04-17
Baso team participated in two academic conferences in succession:
April 11-12: 2025 Annual Meeting of Department Directors of Clinical Laboratories from Guangdong Healthcare Institutions (Guangzhou)
April 12-13: 2025 Transfusion Medicine Expert Committee Conference organized by the Bethune Charitable Foundation (Jinan)
During these events, the team engaged in exchanges and discussions with attending experts, exploring how advanced manufacturing technologies can better serve healthcare institutions and contribute to the future of human health.
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