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| Bacterial pneumonia | |
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| 3D medical animation still showing Streptococcus pneumoniae bacteria (causative bacteria of much bacterial pneumonia and meningitis). | |
| Specialty | Infectious disease |
| Causes | Bacterial infection |
Bacterial pneumonia is a type of pneumonia caused by bacterial infection. [1]
Streptococcus pneumoniae (J13) is the most common bacterial cause of pneumonia in all age groups except newborn infants. Streptococcus pneumoniae is a Gram-positive bacterium that often lives in the throat of people who do not have pneumonia.
Other important Gram-positive causes of pneumonia are Staphylococcus aureus (J15.2) and Bacillus anthracis .
Gram-negative bacteria are seen less frequently: Haemophilus influenzae (J14), Klebsiella pneumoniae (J15.0), Escherichia coli (J15.5), Pseudomonas aeruginosa (J15.1), Bordetella pertussis , and Moraxella catarrhalis are the most common.
These bacteria often live in the gut and enter the lungs when contents of the gut (such as vomit or faeces) are inhaled.
Pneumonia caused by Yersinia pestis is usually called pneumonic plague. [2]
Atypical bacteria causing pneumonia are Coxiella burnetii , Chlamydophila pneumoniae (J16.0), Mycoplasma pneumoniae (J15.7), and Legionella pneumophila .
The term "atypical" does not relate to how commonly these organisms cause pneumonia, how well it responds to common antibiotics or how typical the symptoms are; it refers instead to the fact that these organisms have atypical or absent cell wall structures and do not take up Gram stain in the same manner as gram-negative and gram-positive organisms.
Bacteria typically enter the lung with inhalation, though they can reach the lung through the bloodstream if other parts of the body are infected. Often, bacteria live in parts of the upper respiratory tract and are continuously being inhaled into the alveoli, the cavities deep in the lungs where gas exchange takes place. Once inside the alveoli, bacteria travel into the spaces between the cells and also between adjacent alveoli through connecting pores. This invasion triggers the immune system to respond by sending white blood cells responsible for attacking microorganisms (neutrophils) to the lungs. The neutrophils engulf and kill the offending organisms but also release cytokines that result in a general activation of the immune system. This results in the fever, chills, and fatigue common in bacterial and fungal pneumonia. The neutrophils, bacteria, and fluid leaked from surrounding blood vessels fill the alveoli and result in impaired oxygen transportation.
Bacteria can travel from the lung into the blood stream (bacteremia) and can result in serious illness such as sepsis and eventually septic shock, in which there is low blood pressure leading to damage in multiple parts of the body including the brain, kidney, and heart. They can also travel to the area between the lungs and the chest wall, called the pleural cavity.
In some very rare cases, bacterial pneumonia can form from someone throwing up and then falling asleep on their side causing some stomach fluid to funnel into the lungs leading to this infection.
Diagnosis is carried out in steps.
Patient history is obtained, including the symptoms and their duration, as well as exposure to any risk factors of the disease. A chest X-ray may be performed to check for signs of inflammation [5] and a complete blood count will also be obtained. A sputum sample will also be obtained to ascertain the causative bacteria. This also plays a role in informing treatment options. [5] [6]
In some cases, pulse oximetry may also be required as pneumonia is known to deplete oxygen levels in the blood. [7] Other vitals such as pulse and body temperature are also checked.
Depending on the general health, severity of the disease and age of the patient, several other tests may be required, such as:
Prevention of bacterial pneumonia is by vaccination against Streptococcus pneumoniae (pneumococcal polysaccharide vaccine for adults and pneumococcal conjugate vaccine for children), Haemophilus influenzae type B, meningococcus, Bordetella pertussis, Bacillus anthracis, and Yersinia pestis.
Antibiotics are the treatment of choice for bacterial pneumonia, with ventilation (oxygen supplement) as supportive therapy. The antibiotic choice depends on the nature of the pneumonia, the microorganisms most commonly causing pneumonia in the geographical region, and the immune status and underlying health of the individual. In the United Kingdom, amoxicillin is used as first-line therapy in the vast majority of patients acquiring pneumonia in the community, sometimes with added clarithromycin. In North America, where the "atypical" forms of community-acquired pneumonia are becoming more common, clarithromycin, azithromycin, or fluoroquinolones as single therapy have displaced the amoxicillin as first-line therapy. Local patterns of antibiotic resistance always need to be considered when initiating pharmacotherapy. Another common antibiotic used is called zithromax, this treats many other bacterial infections. In hospitalized individuals or those with immune deficiencies, local guidelines determine the selection of antibiotics.
Streptococcus pneumoniae — amoxicillin (or erythromycin in patients allergic to penicillin); cefuroxime and erythromycin in severe cases.
Staphylococcus aureus — flucloxacillin (to counteract the organism's β-lactamase).
People who have difficulty breathing due to pneumonia may require extra oxygen. An extremely sick individual may require artificial ventilation and intensive care as life-saving measures while his or her immune system fights off the infectious cause with the help of antibiotics and other drugs.
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity of the condition is variable.
Sputum is mucus that is coughed up from the lower airways. In medicine, sputum samples are usually used for a naked eye examination, microbiological investigation of respiratory infections and cytological investigations of respiratory systems. It is crucial that the specimen does not include any mucoid material from the nose or oral cavity.
Acute bronchitis, also known as a chest cold, is short-term bronchitis – inflammation of the bronchi of the lungs. The most common symptom is a cough. Other symptoms include coughing up mucus, wheezing, shortness of breath, fever, and chest discomfort. The infection may last from a few to ten days. The cough may persist for several weeks afterward with the total duration of symptoms usually around three weeks. Some have symptoms for up to six weeks.
Atypical pneumonia, also known as walking pneumonia, is any type of pneumonia not caused by one of the pathogens most commonly associated with the disease. Its clinical presentation contrasts to that of "typical" pneumonia. A variety of microorganisms can cause it. When it develops independently from another disease, it is called primary atypical pneumonia (PAP).
Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, spherical bacteria, alpha-hemolytic member of the genus Streptococcus. S. pneumoniae cells are usually found in pairs (diplococci) and do not form spores and are non motile. As a significant human pathogenic bacterium S. pneumoniae was recognized as a major cause of pneumonia in the late 19th century, and is the subject of many humoral immunity studies.
Azithromycin, sold under the brand names Zithromax and Azasite, is an antibiotic medication used for the treatment of a number of bacterial infections. This includes middle ear infections, strep throat, pneumonia, traveler's diarrhea, and certain other intestinal infections. Along with other medications, it may also be used for malaria. It is administered by mouth, into a vein, or into the eye.
Haemophilus influenzae is a Gram-negative, non-motile, coccobacillary, facultatively anaerobic, capnophilic pathogenic bacterium of the family Pasteurellaceae. The bacteria are mesophilic and grow best at temperatures between 35 and 37 °C.
Lower respiratory tract infection (LRTI) is a term often used as a synonym for pneumonia but can also be applied to other types of infection including lung abscess and acute bronchitis. Symptoms include shortness of breath, weakness, fever, coughing and fatigue. A routine chest X-ray is not always necessary for people who have symptoms of a lower respiratory tract infection.
The bacterial capsule is a large structure common to many bacteria. It is a polysaccharide layer that lies outside the cell envelope, and is thus deemed part of the outer envelope of a bacterial cell. It is a well-organized layer, not easily washed off, and it can be the cause of various diseases.
Community-acquired pneumonia (CAP) refers to pneumonia contracted by a person outside of the healthcare system. In contrast, hospital-acquired pneumonia (HAP) is seen in patients who have recently visited a hospital or who live in long-term care facilities. CAP is common, affecting people of all ages, and its symptoms occur as a result of oxygen-absorbing areas of the lung (alveoli) filling with fluid. This inhibits lung function, causing dyspnea, fever, chest pains and cough.
Lobar pneumonia is a form of pneumonia characterized by inflammatory exudate within the intra-alveolar space resulting in consolidation that affects a large and continuous area of the lobe of a lung.
Pneumococcal pneumonia is a type of bacterial pneumonia that is caused by Streptococcus pneumoniae (pneumococcus). It is the most common bacterial pneumonia found in adults, the most common type of community-acquired pneumonia, and one of the common types of pneumococcal infection. The estimated number of Americans with pneumococcal pneumonia is 900,000 annually, with almost 400,000 cases hospitalized and fatalities accounting for 5-7% of these cases.
Gemifloxacin mesylate, sold under the brand name Factive among others, is a broad-spectrum quinolone antibacterial agent used in the treatment of acute bacterial exacerbation of chronic bronchitis and mild-to-moderate pneumonia. It is taken by mouth. Vansen Pharma Inc. licensed the active ingredient from LG Life Sciences of Korea.
Hospital-acquired pneumonia (HAP) or nosocomial pneumonia refers to any pneumonia contracted by a patient in a hospital at least 48–72 hours after being admitted. It is thus distinguished from community-acquired pneumonia. It is usually caused by a bacterial infection, rather than a virus.
Ceftibuten is a third-generation cephalosporin antibiotic. It is an orally administered agent, with two dosage forms, capsule or oral suspension. It is marketed by Pernix Therapeutics under the trade name Cedax.
Cefditoren, also known as cefditoren pivoxil is an antibiotic used to treat infections caused by Gram-positive and Gram-negative bacteria that are resistant to other antibiotics. It is mainly used for treatment of community acquired pneumonia. It is taken by mouth and is in the cephalosporin family of antibiotics, which is part of the broader beta-lactam group of antibiotics.
Cefodizime is a 3rd generation cephalosporin antibiotic with broad spectrum activity against aerobic gram positive and gram negative bacteria. Clinically, it has been shown to be effective against upper and lower respiratory tract infections, urinary tract infections, and gonorrhea. Cefodizime is a bactericidal antibiotic that targets penicillin-binding proteins (PBPs) 1A/B, 2, and 3 resulting in the eventual death of the bacterial cell. In vivo experimental models of infection showed that bacterial clearance by this drug is at least as effective compared with other 3rd generation cephalosporins. It has similar adverse effect profile to other 3rd generation cephalosporins as well, mainly being limited to gastrointestinal or dermatological side effects.
Pneumococcal infection is an infection caused by the bacterium Streptococcus pneumoniae.
An acute exacerbation of chronic obstructive pulmonary disease, or acute exacerbations of chronic bronchitis (AECB), is a sudden worsening of chronic obstructive pulmonary disease (COPD) symptoms including shortness of breath, quantity and color of phlegm that typically lasts for several days.
Pneumonia can be classified in several ways, most commonly by where it was acquired, but may also by the area of lung affected or by the causative organism. There is also a combined clinical classification, which combines factors such as age, risk factors for certain microorganisms, the presence of underlying lung disease or systemic disease and whether the person has recently been hospitalized.