What Are the Different Legionella Tests?

Legionella, aerobic Gram-negative bacilli, are most likely to cause disease with Legionella pneumophila. More than 30 species of Legionella have been proposed, and at least 19 are pathogens of human pneumonia. The most common pathogens are Legionella pneumophila (85% to 90% of cases), followed by L.micdadei (5% to 10%), and again L.bozemanii and L.dumoffii. These bacteria have similar morphology, Has common biochemical characteristics and causes similar diseases.

Legionella is a kind of opportunistic pathogen widely existing in nature. It can cause fever and respiratory symptoms. It is called legionnaires'diseasesLD. The most common and serious clinical type is Legionella pneumonia, predominantly with pulmonary infections and systemic multisystem damage ^[1]

(1) Asymptomatic serum changes; (2) Influenza-like morbidity of self-limited asymptomatic pneumonia, sometimes called Pontiac fever; (3) Legionnaires' disease is the most severe and common type of pneumonia; (4) Limitations, rare soft tissue infections.

Legionella pneumophila is an outbreak. Legionnaires' disease can occur at any age, but most people are middle-aged men. Identified risk factors include smoking, abuse

Legionella is a pathogenic bacteria hidden in the air-conditioning refrigeration unit, which floats in the air with the cold wind and will appear after inhalation

Bacterial culture method

Legionella are Gram-negative bacilli, obligate aerobic, intracellular parasites. Legionella was originally isolated from guinea pigs infected with lung tissue from patients with Legionella. Although this method has high reliability, it is very expensive and time consuming, and it was soon replaced by the plate culture method ^[2]

Temperature sterilization: heat water to at least 70 ° for three minutes.

Chemical sterilization: Mostly use chlorine,

Legionellosis is a lung infection caused by bacteria of the Legionella family. Sporadic onset or pandemic, but also outbreaks. Infections are caused by air-conditioning, water supply systems, and aerosolized contaminated water sources. The disease is characterized by pneumonia with symptoms of systemic toxemia, and severe cases of peripheral circle failure and respiratory failure. The chest X-ray showed a single-lobed patchy shadow in the early stage, followed by consolidation of the lungs, and the lesions quickly developed to multiple lung lobe segments, with pulmonary abscess formation or a small amount of pleural effusion. The diagnosis depends on the detection of specific antibodies and the isolation of bacteria from sputum, pleural effusion, and lung biopsy specimens. Erythromycin and rifampicin have a better therapeutic effect on this disease ^[3] .

Clinical manifestations of Legionella

1. Slow onset, repeated chills, high fever, headache, myalgia, fatigue, abdominal pain, vomiting, diarrhea, and general failure. Most patients have cough, chest pain, a small amount of mucus, and bloody sputum. Severe patients have dyspnea, cyanosis, and even respiratory failure, neuropsychiatric symptoms, delirium, and disorientation.

2. Acute illness, shortness of breath. There are rales and consolidation signs in the lungs. About 20% have relatively slow pulses. Few patients have pleural friction.

Diagnosis of Legionella

1. Can be epidemic or sporadic, mostly in middle-aged or elderly patients with chronic diseases.

2. Fever, sweating, coughing, coughing up sputum, chest pain, myalgia and fatigue. Nervous, psychiatric symptoms or nausea, vomiting, diarrhea, and severe renal failure may occur.

3 Difficulty breathing and relatively slow pulse. The lungs may have wet rales and consolidation signs or pleural friction.

4 The total number of white blood cells is increased, liver function may be abnormal, and blood urea nitrogen is increased.

5. The chest X-ray shows a patchy shadow that changes rapidly in a single leaf or multiple leaves, often accompanied by abscess formation and pleural effusion.

6. Special inspection: Direct fluorescent antibody test is positive. Lung biopsies were positive with Legionella staining; indirect fluorescent antibody tests were positive. Specific serum antibody titration> 1: 256, or 4 times higher than in duplicate serum; radioimmunoassay or melanin immunosorbent assay for soluble bacterial antigen in urine, Legionella pneumophila in special culture of sputum, pleural fluid and lung Grow.

Legionella treatment principles

1. Antibacterial therapy.

2. Symptomatic treatment.

3 Supportive therapy.

Legionella Medication Principles

1. Mild cases are mainly oral erythromycin and other auxiliary drugs.

2. The heavier patients are given intravenous drip infusions of erythromycin for 2-3 weeks, and treated with other auxiliary drugs.

3 In addition to intravenous injection of erythromycin in severe patients, rifampicin and doxycycline can be combined. Support symptomatic and comprehensive treatment. To avoid recurrence, the course of the disease takes more than 3 weeks.

4 Aminoglycoside antibiotics, penicillin and cephalosporins are not effective for this disease.

Legionella- assisted examination

1. The examination project for patients with early legionella pneumonia is mainly based on the "A"

2. When the disease needs to be distinguished from pneumonia infected by other pathogenic bacteria, the inspection program may include the inspection frame "A", "B", or "C".

Evaluation of Legionella Efficacy

1. Cure: normal body temperature, symptoms and signs disappeared, X-ray showed complete absorption of lung shadows; sputum or bronchial lavage fluid culture was negative.

2. Improvement: normal body temperature, symptoms and signs disappeared, X-ray showed basic absorption of lung shadows; sputum or bronchial lavage fluid culture was negative.

3 Unhealed: No change or worsening of symptoms and signs after 1 month of treatment ^[4] .