Streptococcal pneumonia is an inflammatory disease of the lungs caused by Streptococcus pneumoniae. Streptococcus pneumoniae remains the main causative agent of community-acquired pneumonia (CAP) today. In recent years, with the widespread use of antimicrobial drugs, the drug resistance of Streptococcus pneumoniae has changed, resulting in an atypical pattern of disease initiation, clinical presentation and imaging changes, and changes in treatment options. I. Etiology and epidemiology Streptococcus pneumoniae is a gram-positive bacterium, and more than 90 serotypes have been identified. 19F, 19A and 14 are the most common serotypes in cases of pneumonia and meningitis in children under 5 years old in China. 19F, 19A, 3, 23F and 15 are the common serotypes of Streptococcus pneumoniae isolated from adult patients in China. The results of the 2011 CHINET bacterial resistance surveillance in China showed that Streptococcus pneumoniae accounted for 6.66% of gram-positive bacteria. The previous (2005) bacterial resistance surveillance showed that Streptococcus pneumoniae was 61% insusceptible to penicillin, 67%-75% resistant to erythromycin and clindamycin by penicillin-susceptible strains, and up to 90% or more resistant to erythromycin by penicillin-insusceptible strains.In 2008, the U.S. Committee on Clinical and Laboratory Standardization (CLSI) folded penicillin (non-oral) against Streptococcus pneumoniae The fold point for non-meningitis isolates was adjusted from ≤0.06 mg/ml to ≤2 mg/ml for susceptibility and ≥8 mg/ml for resistance (R); after the fold point change, the 2011 CHINET Streptococcus pneumoniae resistance surveillance showed that pediatric isolates were 73.6% susceptible to penicillin and adult isolates were up to 93.1% susceptible to penicillin; however, pediatric strains were Erythromycin resistance rate was more than 97% in children and 91% in adults; all isolates were <2% resistant to levofloxacin and <1% resistant to moxifloxacin. Thus, after the penicillin fold adjustment, the sensitivity rate of Streptococcus pneumoniae non-meningitis isolates to penicillin was significantly higher, but the resistance rate to macrolides remained high. In recent years, with the increased use of fluoroquinolone antibacterial drugs, resistant strains of Streptococcus pneumoniae have also started to appear and have a tendency to gradually increase. Clinical manifestations Patients are often previously healthy young adults or the elderly and infants, and often have a history of cold, rain, fatigue, alcohol abuse, and viral infections before the onset of the disease. The onset of the disease is more acute, with the prodromal symptoms of upper respiratory tract infection, sudden onset of high fever, chills, muscle aches, and increased pulse rate; there may be chest pain, and sputum may be bloody or rust-colored. In the early stage, there is no obvious abnormality in pulmonary signs; bronchial breath sounds can be heard in solid lung changes; wet rales can be heard in the dissipation stage. In the early stage of imaging, only thickened lung texture is seen; as the disease progresses, it shows a large inflammatory infiltrative shadow or solid shadow, and there may be a small amount of pleural effusion. Streptococcus pneumoniae is also the main pathogen of influenza-associated pneumonia, and Streptococcus pneumoniae infection is a common and serious complication of influenza. III. Diagnosis The diagnosis of pneumonia should be established first, which can be done by referring to the diagnostic criteria of CAP. The most important question is whether further pathogenic testing is needed for Streptococcus pneumoniae pneumonia?The 2009 British Thoracic Society (BTS) guidelines for CAP suggest that routine pathogenic testing is not necessary for CAP patients treated in the community unless empiric therapy is ineffective, while pathogenic testing should be performed in all patients with moderate to severe CAP, and the scope of testing can be selected according to severity; the 2007 American College of Infectious Diseases/Infectious Diseases Society of America (IDSA) guidelines for CAP are not available. American Thoracic Society (IDSA/ATS) guidelines for CAP, however, recommend that outpatients with CAP also have the option of routine pathogenic diagnosis depending on their condition. For severe CAP, both IDSA/ATS and BTS strongly recommend blood and sputum cultures, and blood cultures should be performed before antibiotics are administered, especially for Streptococcus pneumoniae, which are easily influenced by antibiotics, and even if blood cultures are performed before antibiotics are administered, the probability of detecting the causative agent is only 4-15%; the BTS guidelines recommend that if the diagnosis of CAP is clear and the patient is If the diagnosis of CAP is clear and the patient is mild, blood cultures may not be done. The rate of positive sputum cultures for Streptococcus pneumoniae in patients with pneumococcal pneumoniae bacteremia is 40% to 50%. It is recommended that all patients with moderate to severe CAP should be tested for Streptococcus pneumoniae urinary antigen with a sensitivity of 50% to 80% and a specificity of >90%. Many other body fluids including sputum, pleural fluid, and serum can detect Streptococcus pneumoniae antigen, and Streptococcus pneumoniae urinary antigen testing can still be 80-90% positive after 7 days of antibiotic treatment and is not affected by the use of antibiotics. However, patients with Streptococcus pneumoniae colonization and those who had CAP within 3 months were prone to false positive results. IV. Treatment Pay attention to rest and keep indoor air circulation. Give adequate amount of vitamins and proteins. Drink plenty of water and eat small meals. Keep the airway open. Give oxygen and other symptomatic treatment as appropriate. The 2006 guidelines for diagnosis and treatment of CAP in China state that for penicillin-mediated levels of Streptococcus pneumoniae pneumonia, penicillin can still be selected, but the dose needs to be increased, such as penicillin G 2.4 million intravenous drip, 1 time/4~6h; high levels of resistance or the presence of high risk factors for resistance should be selected ceftriaxone, cefotaxime, ertapenem, respiratory quinolone or vancomycin; Streptococcus pneumoniae in China is resistant to In addition, antibiotic therapy should be started as early as possible, and the first dose of antibiotic therapy should be used within 4h after diagnosis to improve the efficacy, reduce the morbidity and mortality rate, and shorten the hospitalization time. 2007 IDSA/ATS CAP guideline treatment recommendation: penicillin MIC <2mg/ml, penicillin is preferred G, amoxicillin, with macrolides and cephalosporins as secondary choices; penicillin MIC ≥ 2 mg/ml, cefotaxime, ceftriaxone, fluoroquinolone (with levofloxacin dose of 750 mg/d), and linezolid and vancomycin may be considered if resistant; oral high-dose amoxicillin (1 g, 3/day) may also be chosen for penicillin MIC ≤ 4 mg/ml. After the penicillin fold adjustment, penicillin remains the preferred choice for the treatment of Streptococcus pneumoniae pneumonia. 2009 BTS guidelines on CAP recommend that treatment is preferred to penicillin G intravenously at a dose of 1.2g, 4/day; or amoxicillin 500mg~1g, orally, 3/day; alternative options are clarithromycin 500mg, orally, 2/day, cefuroxime 0.75~1g, sedation , 3/day, cefotaxime 1~2g, sedation, 3/day, ceftriaxone 2g, sedation, 1/day. For patients with hemodynamic stability, improved clinical symptoms and normal GI function, antibiotic intravenous medication can be changed to oral and discharged to continue treatment with at least 5 days of anti-infective therapy, and antibiotics can be discontinued without fever for 48-72 hours. The recommended course of antibiotics for outpatients and mildly hospitalized patients is 7 days. V. Prevention Quit smoking, quit drinking, strengthen physical exercise, and live a regular life and rest. Streptococcus pneumoniae polysaccharide vaccine is strongly recommended for people older than 65 years old and those with risk factors for Streptococcus pneumoniae infection. Currently, there are two types of pneumococcal vaccines commercially available in China, namely, pneumococcal conjugate vaccine (PCV) and pneumococcal polysaccharide vaccine (PPV). PCV has good immunogenicity in healthy infants and children and can induce protective immune responses in patients with various types of immunodeficiency. PCV7, which is recommended for infants and children aged 3 to 23 months and children aged 24 to 59 months who have not received PCV7; a survey in the United States showed that the hospitalization rate of pneumococcal pneumonia in children under 2 years of age decreased by 65% and that of children aged 2 to 4 years decreased by 73% after the inclusion of PCV7 in the immunization program. The PPV marketed in China is PPV23, which is recommended for use in elderly people over 60 years of age and people aged 2-59 years with high-risk factors; in immunocompetent adults and people with underlying diseases but not severe immunodeficiency, the effectiveness of PPV23 in preventing IPD is 50%-80%.