Anaerobic bacterial pneumonia

　　Under normal circumstances, the normal anaerobic bacteria resident in the human body are beneficial and harmless. However, when the body's defense function is weakened, the resident normal flora changes, and anaerobic bacteria leave their original place and transfer to usually non-resident tissues and organs, leading to endogenous infection. The oxidation-reduction potential in human tissues can prevent the proliferation of anaerobic bacteria. In cases of immune damage such as low immunoglobulinemia, complement deficiency, neutropenia, and cell-mediated immune deficiency, the host is more susceptible to anaerobic bacterial infections, thus suggesting that the damage to the skin and mucosal defense barrier is the key to anaerobic bacterial infections and disease. The main pathogenic factors of anaerobic bacterial pneumonia include changes in the flora of the upper respiratory tract, abnormal colonization, and aspiration caused by various triggers, with the latter being the most important. Periodontal diseases (gingivitis and periodontitis) are the usual sources of anaerobic bacterial colonization. Anaerobic bacteria usually fall into four major categories:

　　1. Anaerobic cocci include Gram-positive peptostreptococcus, peptococcus, anaerobic streptococcus, and Gram-negative Veillonella genus. Peptostreptococcus is particularly common in pleuropulmonary infections.

　　2. Gram-negative anaerobic bacilli Gram-negative anaerobic bacilli are very common in pulmonary anaerobic infections. The Bacteroides genus is the most common, followed by the Fusobacterium genus, with rare cases of Cilia bacteria. The most common species in the Bacteroides genus are Bacteroides fragilis, Bacteroides melaninogenicus, and Bacteroides oralis. The Fusobacterium genus includes Fusobacterium nucleatum, Fusobacterium necrophorus, Fusobacterium variabile, and Fusobacterium mortiferum.

　　3. Gram-positive, non-spore-forming bacilli include Propionibacterium, Eubacterium, Lactobacillus, Actinomyces, and Bifidobacterium. Among them, Eubacterium, Propionibacterium, and Bifidobacterium are common in pulmonary anaerobic infections.

　　4. Clostridial bacteria include Clostridium botulinum, Clostridium perfringens, Clostridium tetani, and they rarely cause pulmonary infections.

　　The main complications of anaerobic pneumonia include empyema and bronchopleural fistula, with symptoms such as confusion, irritability, drowsiness, and coma. In the early stage, there are no obvious abnormalities in pulmonary signs, and severe cases may have increased respiratory rate, flaring of the nostrils, and cyanosis. Typical signs are present during lung consolidation, such as dullness on percussion, increased vocal resonance, and bronchial breath sounds, as well as wet rales. In patients with pleural effusion, the affected side of the lung has dullness on percussion, decreased vocal resonance, and reduced breath sounds.

　　Anaerobic pneumonia is more common in elderly people over 50 and males. The incubation period for simple anaerobic pneumonia is 3 to 4.5 days, while the incubation period for lung abscess or empyema generally requires 2 weeks. The clinical manifestations are very diverse, ranging from general acute bacterial pneumonia to subacute or chronic progression or a hidden infection similar to tuberculosis. 40% to 60% of patients with lung abscess or empyema may have weight loss or anemia, among whom almost all chronic lung abscesses or empyemas are emaciated and anemic, while simple anaerobic pneumonia rarely appears (5%), and the malodorous sputum or pleural fluid characteristic of anaerobic infection is seen in 50% to 70% of lung abscesses or empyemas, but only 4% of simple anaerobic pneumonia coughs up malodorous sputum. Pulmonary signs may include consolidation or pleural effusion, and chronic lung abscesses often have clubbing of the fingers (toes).

　　Pulmonary anaerobic infections, especially aspiration pneumonia, are mostly caused by aspiration, so it is necessary to minimize the risk of aspiration. When feeding patients with weakness, consciousness disorders, and swallowing difficulties, special care should be taken, and the bed should be appropriately elevated. When visible aspiration is found, immediate and rapid postural drainage or aspiration to clear the contents in the airway should be performed, and fiberoptic bronchoscopy may be necessary to remove food debris from the large airway to prevent obstruction. In addition, maintaining oral hygiene and actively treating suppurative infections in the abdominal and pelvic cavities can also reduce the occurrence of pulmonary anaerobic infections. The prognosis of pulmonary anaerobic infections depends on the patient's overall condition, the type of infection, and whether the treatment is timely. Old age, systemic failure, necrotizing pneumonia, and bronchial obstruction are all poor prognostic factors. Patients who start treatment in the aspiration pneumonia stage can show effects in 3-4 days and defervescence in 7-10 days. If the fever persists after 7-10 days of treatment, fiberoptic bronchoscopy should be performed to clarify the cause and perform drainage. If it is still ineffective, other diagnoses and other antibiotics should be considered. If空洞 damage occurs, it often takes several months to absorb and close. If the diameter of the cavity is greater than 6 cm, it is difficult to close, and symptoms often disappear only after 8 weeks of treatment. If empyema occurs, even with effective drainage, it takes an average of 29 days to defervescence. Socially acquired aspiration pneumonia has a good prognosis. A report showed that 4% of deaths were due to anaerobic pneumonia, and 7% were due to it as a trigger; on the contrary, hospital-acquired aspiration pneumonia has a mortality rate of up to 20%, which may be related to severe underlying diseases and the pathogenicity of Gram-negative anaerobic bacilli. The mortality rate of lung abscess was as high as 34% before the use of antibiotics, with only 50% of patients surviving, and it has now decreased to 5%-12%.

　　The main examinations for anaerobic pneumonia include sputum culture, chest MRI, chest CT examination, blood routine, blood biochemistry six items examination, and stool routine. The total number of peripheral blood cells and neutrophils increase, especially the elevation of lung abscess and empyema is particularly obvious, with an average of 1.5×10^10/L and 2.2×10^10/L, respectively. The average white blood cell count in patients with simple pneumonia is 1.3×10^10/L, rarely exceeding 1.5×10^10/L. Chest X-ray films show uniform and dense consolidation shadows along the segmental distribution, which are more common in the posterior segment of the upper lobe and the dorsal segment of the lower lobe. The initial formation of lung abscess is often circular with a smooth inner wall. In chronic lung abscess, the wall becomes thickened, the size of the abscess cavity varies, with a diameter of only 1-1.5 cm in the smaller ones, and up to 13-15 cm in the larger ones. The shape of the abscess cavity is irregular, and most are accompanied by a liquid level. Hematogenous infection is often bilateral, with patchy, patchy consolidation shadows, more common in the lower lobe, and may be accompanied by empyema or pyopneumothorax.

　　Patients with anaerobic pneumonia should eat foods that clear heat and detoxify, antibacterial and anti-inflammatory, and moisten the throat and dissolve phlegm. They should avoid eating spicy foods such as white wine, chili, and Sichuan pepper; avoid eating high-fat foods such as lard, pork fat, and mutton fat; and avoid eating difficult-to-digest foods such as chestnuts and zongzi. Foods containing natural antibiotics include ginger, white scallion, and garlic, which can significantly improve the symptoms of anaerobic pneumonia when eaten in moderation. The specific details are as follows:

　　Firstly, ginger

　　1. It can participate in cell immunity, improve the activity of lysosomes, and has varying degrees of inhibitory and killing effects on Salmonella typhi, Vibrio cholerae, Trichophyton violaceum, Trichomonas vaginalis, and can be used for the prevention and treatment of skin, nail infections, and external genital infections caused by Trichomonas vaginalis.

　　2. Method: Boil 10 grams of fresh ginger in 200 milliliters of water for 10-15 minutes and then take the juice, taken twice a day, once in the morning and once in the evening.

　　Secondly, white scallion and garlic

　　1. The main component is allicin, which has inhibitory effects on Corynebacterium diphtheriae, Mycobacterium tuberculosis, Shigella, Staphylococcus, Streptococcus, and dermatophytes. It can activate the release of body lysosomes, causing the pathogenic bacteria cells to lyse and die, thereby exerting an anti-infection effect. It has a significant effect on the prevention of upper respiratory tract infections, dysentery, enteritis, and other infectious diseases.

　　2. Method: Wash and chop 500 grams of white scallion, peel and slice 250 grams of garlic, cut and cook 250 grams of chicken into pieces, then add the chopped scallion and garlic and boil for another 5 minutes. Eat once a day.

　　The in vitro activity of anaerobic bacteria of different species against antibacterial drugs, and the anti-anaerobic drugs that are almost always effective in clinical practice are metronidazole (except for some non-spore-forming Gram-positive cocci), chloramphenicol, imipenem, beta-lactams/beta-lactamase inhibitors, and the main ones that are usually effective include clindamycin, cefoxitin, cefotetan, cefmezole, and penicillin against Pseudomonas aeruginosa. Currently, penicillin is still used as the first-line drug for the treatment of anaerobic pneumonia. It is administered intravenously by infusion at a high dose of 6 million to 10 million U/d. Levison conducted a prospective study on the efficacy of clindamycin and penicillin in the treatment of lung abscess, and the results showed that clindamycin was superior to penicillin in terms of the number of treatment failures, the number of recurrence cases, and the duration of fever and sputum with a foul smell. Therefore, clindamycin can also be used as the first-line drug for initial treatment, especially when penicillin allergy or pathogenic confirmation of penicillin-resistant bacterial infection is present. Metronidazole (Diaminodichloroethane) has a good bactericidal effect on various anaerobic bacteria, with the MIC mostly less than 0.2 μg/ml. Metronidazole 0.4 to 0.6g, 3 to 4 times/d, taken orally; or 1.5g/d intravenous infusion, has a good effect on the treatment of pulmonary anaerobic infections. However, in a group of 28 patients treated with metronidazole alone, 12 cases (43%) failed to respond to treatment, so metronidazole is usually combined with other drugs (penicillin, clindamycin). Cephamycin and carbapenem antibiotics can be selected for severe patients. The course of antibacterial treatment for anaerobic pneumonia without complications is 2 to 4 weeks, for necrotizing pneumonia or lung abscess, it is 6 to 12 weeks.

　　Drainage is very important for patients with empyema complications due to anaerobic lung infection. Postural drainage helps to expel sputum. Fiberoptic bronchoscopy is sometimes also used for sputum aspiration from lung abscess. Conservative medical treatment is ineffective or suspected tumor patients are indicated for surgical treatment, with 10% to 20% of lung abscess patients requiring surgery. In cases with obvious systemic toxic symptoms, high surgical risk, or inability to tolerate, interventional radiology techniques can be used for percutaneous abscess cavity drainage. Empyema should be drained through intercostal incision, and if drainage is ineffective, pleurectomy should be performed.

　　Anaerobic lung infection (including empyema after reasonable drainage), antibiotic treatment has a good effect, and the mortality rate has decreased from 30% to 60% in the pre-antibiotic era to 5% to 12% at present. However, it is noteworthy that about half of the survivors may have complications such as bronchiectasis, recurrent pneumonia, or chronic empyema sequelae, which are all related to delayed diagnosis and treatment.