Elderly Gram-positive bacillus pneumonia

　　Gram-positive bacilli include the genus Bacillus, the genus Listeria, the genus Corynebacterium, and the genus Erysipelothrix. Most Gram-positive bacilli are non-pathogenic, except for a few pathogenic bacteria. Bacillus cereus and Bacillus cereus in the genus Bacillus are widely distributed in dust, water, and air and are generally non-pathogenic. Among them, Bacillus anthracis in the genus Bacillus can cause pulmonary anthrax, which is relatively rare at present. Listeria monocytogenes is an important pathogen for meningitis and sepsis in neonates and immunocompromised patients, with almost no reports of pulmonary infections. Corynebacterium diphtheriae, except for Corynebacterium diphtheriae, is commonly referred to as Corynebacterium diphtheriae, including Mycobacterium bovis BCG, Corynebacterium xerosis, and Corynebacterium diphtheriae, etc., which are normal flora in the oropharynx or skin and are rarely pathogenic in immunocompromised patients. However, there have been reports recently about Corynebacterium, especially the JK group, causing sepsis, infective endocarditis, and venous catheter infections, which are worthy of attention. Erysipelothrix and Lactobacillus are generally considered non-pathogenic, but occasionally they can cause pulmonary infections and sepsis.

　　Bacillus anthracis is a Gram-positive bacillus, aerobic and anaerobic, with large, 4～8mm long, non-flagellated, non-motile, which can form spores in unfavorable environments. It grows well on general culture media and has a very strong resistance (can survive for years in fur). It dies after boiling for 40min, dry heat at 140℃ for 3h, high-pressure steam at 110℃ for 10min, and flowing steam at 100℃ for 60min. It can secrete anthrax toxin during reproduction, which is a complex polymer composed of edema factor, protective antigen, and necrotizing factor.

　　Elderly positive bacillary pneumonia commonly has complications such as sepsis, meningitis, shock, respiratory and circulatory failure, most of which are related to the original various underlying diseases, common ones include: shock, sepsis, pyemia, arrhythmia, electrolyte imbalance, acid-base imbalance, respiratory failure, heart failure, multiple organ dysfunction syndrome, etc. After the complications appear, the condition is serious, progresses rapidly, and the mortality rate is high. Elderly patients often do not have chest pain but only present with progressive worsening of dyspnea. Due to the poor basic pulmonary function of elderly patients, even if the lung compression is not much, it shows toxicity, and must be rescued in time.

　　Primary inhalational anthrax is the most common, with a few cases secondary to skin anthrax, with an incubation period of 1～7 days, usually 2～3 days, sudden onset, acute onset, or may have 2～4 days of symptoms similar to common cold before sudden onset.

　　The clinical manifestations are often chills, high fever, dyspnea, chest pain, hemoptysis-like sputum, cyanosis, scattered moist rales in the lungs, occasionally subcutaneous edema in the neck and chest, with relatively mild signs that are not proportional to the severity of the disease. If not treated in time, most patients will die of respiratory and circulatory failure within 24～48h.

　　The skin shows necrosis and ulceration, with characteristic features of a cross-like carbon burn, which is a typical change.

　　Isolation and treatment should be carried out when the illness has not been cured. The patient's room should reduce personnel flow, pay attention to cold prevention and warmth, and try to stay away from crowded public places during the epidemic period. Improve the hypoxia state, which can be treated with home oxygen therapy, take expectorant drugs orally, drink more water to moisten sputum, and facilitate expectoration. Strengthen functional exercise, increase nutritional support, and give immunostimulants.

　　The clinical examination of elderly positive bacillary pneumonia is as follows:

　　First, blood routine

　　The peripheral blood leukocyte count in patients with anthrax is significantly elevated, generally (10～20)×10^9/L, which can reach up to (60～80)×10^9/L, with an increase in neutrophils.

　　Second, bacteriological examination:

　　Diagnosis relies on direct smear examination of secretions from the wound, skin eschar, sputum, blood, vomit, feces, and cerebrospinal fluid, or isolation of Bacillus anthracis through culture.

　　1. Direct smear examination: CollectDirect smears of specimens from infected sites such as blister fluid from skin anthrax patients, sputum from pulmonary anthrax patients, diarrhea or vomiting from intestinal anthrax patients, cerebrospinal fluid from meningitis patients, etc., are stained with Gram stain, and typical Bacillus anthracis can be identified combined with clinical manifestations. Anthrax spores can be confirmed under a microscope after staining with methylene blue or India ink.

　　2. Bacterial culture identification:The blood culture has a high positive rate, but the positive rate of skin lesion tissue is 60%-80%, the positive rate of nasopharyngeal swabs is even lower. Bacillus anthracis forms long chains or flocculent precipitates in broth culture, forming non-hemolytic, gray, rough colonies on blood plates after 24h at 37℃, under low magnification, the colonies appear curly. Identification:

　　(1) Staphylococcus agglutination test: Bacillus anthracis changes its morphology in a 0.05-0.1U/ml penicillin culture medium, forming round spherical bacterial bodies in a chain-like manner, resembling beads, while atypical anthrax does not have this reaction.

　　(2) Positive carbonate toxicity test: The bacteria to be tested are inoculated on a 0.5% sodium bicarbonate agar plate and placed in a 10% carbon dioxide environment at 37℃ for 24-48h. Toxic strains form a capsule, showing a mucoid type. Non-toxic strains do not form a capsule, showing rough colonies. There are reports of penicillin resistance in clinical cases, so it is necessary to perform drug sensitivity tests on the culture colonies, especially for anthrax cases related to biological terrorism.

　　3. Serological examination:The serological diagnostic value is relatively low, generally used for epidemiological investigation, such as enzyme-linked immunosorbent assay for spore antigens, such as if the antibody titer increases by 4 times, it suggests recent infection or vaccination. Also, enzyme-linked immunoelectrophoresis experiment or indirect hemagglutination test can be used to assist in diagnosis.

　　4. Molecular biological examination:Polymerase chain reaction (PCR) specifically amplifies the Bacillus anthracis or anthrax spore-specific marker, which can be used for diagnosis and typing, and assist in determining the source of infection. The main target gene for PCR diagnosis is the gene encoding the virulence factor, the toxin gene (pagA,lef, and cya) is encoded by the virulence plasmid pXO1, the biosynthesis of the capsule (capB, capC, and capA) is encoded by pXO2. These virulence genes are unique to Bacillus anthracis, therefore, the detection method based on plasmids has a very high specificity. However, there are also reports that some strains of Bacillus anthracis lack these plasmids. Therefore, it is very necessary to develop a method for detecting non-virulent and plasmid-containing Bacillus anthracis that is specific to a chromosomal location. Recently, Qi and others have developed a fluorescence resonance energy transfer PCR method targeting the rpoB gene on the chromosomal location of Bacillus anthracis. This method seems to be the most specific to date. In 175 specimens that were not Bacillus anthracis, only one was reported to be positive. The primer and probe combination: BA1 targets a site on pXO2, BA2 targets pXO1, and BA3 targets a site on the chromosome of Bacillus anthracis.

　　Three, X-ray examination shows

　　Pulmonary infiltration, mediastinal widening, pleural effusion, etc.

　　Elderly patients with positive bacillary pneumonia should adopt light and easily digestible foods in their diet, pay attention to eating more fresh vegetables and fruits appropriately, especially it is recommended to eat more foods such as white fruit, lily, white radish, lotus root slices, and so on. At the same time, avoid eating spicy and刺激性 foods, avoid smoking and drinking, and avoid drinking strong tea.

　　The treatment methods and precautions for elderly patients with positive bacillary pneumonia are as follows:

　　First, drug treatment

　　Active support and symptomatic treatment. Penicillin is the first choice, which can be administered intravenously at a dose of 10 to 20 million units, and combined with aminoglycoside antibiotics for anti-inflammatory therapy, with a course of 2 to 3 weeks. Tetracycline and chloramphenicol can be used in cases of penicillin allergy.

　　Second, precautions

　　1. At home, attention should be paid to observing and measuring body temperature: Body temperature is an important vital sign in pneumonia. Other family members should learn to observe and measure body temperature. The normal armpit temperature of a healthy person is generally around 35-37℃, and a body temperature above 37℃ is considered fever. It can be divided into: moderate fever 38-38.9℃; high fever 39-40℃; and fever above 40℃ as very high fever.

　　Patients with fever should be closely monitored, and attention should be paid to changes in pulse and blood pressure. Encourage patients to drink plenty of water during fever, and intravenous fluid therapy may be given if necessary, with fluid volume ranging from 2500 to 3000ml. Record the intake and output of fluids over 24 hours. Supplement electrolytes, vitamins, and high-calorie diet, and take oral antipyretic drugs or use warm water for bathing.

　　2. Observation and measurement of respiration: Observe changes in respiratory rate and rhythm. Patients with dyspnea should be given oxygen and respiratory tract patency should be maintained. Choose to apply expectorant drugs and bronchodilator drugs. In cases of heart failure, observe changes in cyanosis, blood pressure, and pulse, and provide cardiotonic, diuretic, and vasodilator therapy.

　　3. For patients with hemoptysis, attention should be paid to the amount of hemoptysis, anemia, and blood pressure. Monitor respiratory tract patency to prevent asphyxiation. Keep calm, avoid severe coughing as much as possible, and use appropriate sedatives and cough suppressants if necessary.

　　4. When skin necrosis and ulcers occur, attention should be paid to maintaining skin cleanliness and hygiene, timely cleaning wounds and removing pus, and preventing skin infection.