Pediatric Staphylococcus aureus pneumonia

　　1. Etiology

　　Staphylococci can produce a variety of toxins and enzymes, such as hemolysin, staphylococcal kinase, coagulase, etc. It is generally believed that coagulase is related to the virulence of bacteria. If it is coagulase-negative (such as Staphylococcus epidermidis), it is often a opportunistic pathogen, rarely causing severe diseases, but it is one of the common bacteria causing hospital-acquired infections. In children, especially neonates, immunodeficiency is an important susceptible factor for Staphylococcus aureus infection. Foreign research shows that low birth weight and insufficient gestational age are two high-risk factors for sepsis, and coagulase-negative staphylococci should not be ignored in neonatal blood cultures. The pathogen enters the body through the human body surface or mucosa and is difficult to be killed due to the action of the aforementioned toxins and enzymes, and spreads throughout the body with blood circulation. The lungs are easily involved. There may also be other migrating foci, and the lungs may be directly involved by respiratory tract infections, leading to lung inflammation.

　　2. Pathogenesis

　　Staphylococcus aureus has a strong virulence and can produce hemolysin, plasma coagulase, deoxyribonuclease, and leukocidin. Staphylococcus aureus pneumonia often occurs in subpleural tissue, characterized by extensive hemorrhagic necrosis and the formation of multiple abscesses. Necrosis of the bronchioles and surrounding alveoli causes gas in the airways to enter the surrounding interstitial and alveolar tissue of the necrotic area. Due to the obstruction of the bronchioles by purulent secretions, it becomes a type of valve-like blockage, causing the tension to gradually increase and forming bullae (pneumatoceles). The rupture of abscesses adjacent to the pleura may lead to empyema, pneumothorax, or pyopneumothorax.

　　Progressive pneumonia, which can be fatal, is a common complication, sometimes accompanied by respiratory distress syndrome and/or septic shock. Chest X-ray examination may reveal about 25% of patients with pleural effusion, and a small number have empyema. Some patients may develop infections in the adjacent areas of the lesions (such as empyema or purulent pericarditis). Bacteremia can cause infections outside the lungs, including septic arthritis, endocarditis, meningitis, and (in patients with ascites). Some patients may experience repeated lung infections, manifested as recurrence of fever and new lung infiltrates after temporary improvement during treatment, leading to deterioration of the condition.

　　What are the typical symptoms of Staphylococcus aureus pneumonia in children?

　　How to prevent Staphylococcus aureus pneumonia in children?

　　1, Strengthening physical fitness and improving one's immunity is an effective way to prevent pneumonia.

　　It is necessary to pay attention to the cleanliness of the living environment of nurseries and kindergartens, and it is timely to check whether the staff are carrying the bacteria, and the carriers should be treated in a timely and appropriate manner.

　　1, Blood Count

　　The white blood cell count is generally over (15-30)×10^9/L, with an increase in neutrophils. Poison granules may appear in white blood cells. Half of the small infants may decrease to below 5×10^9/L, while the percentage of neutrophils remains high. A decrease in the total white blood cell count usually indicates a serious prognosis.

　　2, C-Reactive Protein

　　Protein levels increase.

　　3, Bacterial Culture

　　Bacterial culture should be performed on sputum, aspirated material, and pleural fluid aspirated by chest puncture. A positive result is of diagnostic significance.

　　4, Cell Wall Acid

　　It is a phosphorus-containing complex polymer existing on the outer layer of staphylococcus, which can stimulate the body to produce corresponding antibodies. The determination of cell wall acid antibody is helpful for the diagnosis of etiology.

　　5, Ultrasound

　　Liver and spleen enlargement may occur, and pleural effusion, pericardial effusion, etc., may be found.

　　6, Electrocardiogram

　　Myocardial damage may be found.

　　1, Winter Melon Job's Tears Soup

　　Winter melon 500g, mung bean 50g, Job's tears 30g, honeysuckle 15g, fresh lotus leaf 60g, seasonings to taste. Soak the mung bean in clean water for half a day; peel and cut the winter melon into pieces; chop the lotus leaf and put them together in a pot to boil. Add scallion, ginger, garlic, and pepper when it is cooked. Season with salt, monosodium glutamate, and lard to taste when it is ready to eat. Take one dose daily for 3-5 consecutive days. It can relieve the exterior symptoms, clear heat and relieve cough, and expectorate phlegm. It is suitable for pneumonia with cough, high fever with sweating, and general body ache, etc.

　　2. Lonicera and chrysanthemum and rhizoma polygoni multiflori drink

　　Lonicera japonica 20g, Rhizoma polygoni multiflori 80g, chrysanthemum, mulberry leaves, and almond each 10g, honey 30g. Boil the above ingredients with an appropriate amount of water, then simmer over low heat for about 5 minutes, remove the residue and take the juice, mix with honey, and take it in three doses, one dose per day.

　　1. Treatment

　　The general treatment for this disease is the same as that for bronchopneumonia. Due to the severity of the disease, active treatment should be given to control infection as soon as it is suspected to be Staphylococcus aureus pneumonia in the early stage. For methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-sensitive Staphylococcus epidermidis (MSSE), oxacillin (phenoxycillin) and cloxacillin (cloxacillin) are the first choices, and first-generation and second-generation cephalosporins are alternative choices. Penicillin can be administered intravenously at a dose of 100,000 to 500,000 U/(kg·d). Vancomycin or rifampin can be used as the first choice for MRSA and MRSE. A study by Shancai et al. on 108 cases of pediatric staphylococcal infection indicated that vancomycin, ciprofloxacin, and gentamicin are drugs that are more sensitive to methicillin-resistant Staphylococcus (MRS). However, due to the occurrence of multidrug resistance, almost only vancomycin is effective against MRS, and vancomycin-resistant Staphylococcus aureus has also appeared in Japan and the United States. Generally, antibiotics can be discontinued after 7 days of normal body temperature and most pulmonary signs have disappeared, with a treatment course of at least 3 to 4 weeks.

　　When developing empyema or pyopneumothorax, if the amount of pus is small, repeated thoracentesis can be used for pus aspiration treatment; but most children have fast-growing, thick pus that is not easy to aspirate, and closed drainage surgery should be performed. The efficacy of intrathoracic injection of antibiotics is not certain.

　　2. Prognosis

　　Prognosis is severe if complications include Staphylococcus aureus meningitis and pericarditis or neonatal tension pneumothorax. The mortality rate is as high as 10% to 20%. Prognosis is better for complications such as empyema or pyopneumothorax, with cured patients showing no long-term pulmonary dysfunction during long-term follow-up. The prognosis is poor for weak children and newborns.