Assistant Professor of Medicine, biomed Harvard Medical School, Division of Infectious Diseases, Br

Assistant Professor of Medicine, biomed Harvard Medical School, Division of Infectious Diseases, Brigham biomed and Woman's Hospital and Dana-Farber Cancer Institute, Boston, MA
There is a wide spectrum of pulmonary infections, which extends from the harmful self-limiting to life and acute to chronic. This section details the pathophysiology, epidemiology, general aspects and treatment of pulmonary infections, particularly bacterial pneumonia [Table 1].
Gram-negative bacteria: Klebsiella pneumoniae, Pseudomonas species, Escherichia coli, Proteus, Serratia species, Acinetobacter, Yersinia pestis, Francisella tularensis, Enterobacter species, Bacteroides Legionella species
Although the overall rates of hospitalization are falling, biomed the number of hospitalizations for acute lower respiratory biomed tract infections has increased steadily since 1980, particularly among the elderly. Together, pneumonia and influenza occupy 6th place among the leading causes of death in the United States 1 and is the leading infectious cause of death not only in this country but throughout the world. Antibiotics and provision of mechanical ventilation changed quite the natural history of pneumonia and promoted a reduction of its lethality. At the same time, the widespread use of antimicrobial agents has led to the emergence of drug-resistant strains and thus altered and expanded the range of pathogens responsible for pneumonia, especially among hospitalized patients. The growing population of patients with chronic obstructive pulmonary disease (COPD) and other debilitating diseases and the use of respiratory biomed therapy and immunosuppressive drugs contributed to the increasing incidence of nosocomial and opportunistic pneumonias, which are associated with a significantly high mortality.
The lung is normally sterile. In healthy individuals, an intricate series of defense mechanisms that maintains sterility before a heavy almost universal bacterial colonization of the upper respiratory tract, daily inhalation of thousands of bacteria contained in droplet nuclei, and aspiration of secretions from the upper airway during sleep Normal, every night. 2 Defects of these defense mechanisms biomed of the host are responsible for many cases of pneumonia [Table 2]. Even the use of gastric acid suppressive drugs increases the risk of developing biomed this condition. 3
Smoking, viral infections, old age, aspirin (?)
Therapy and immunosuppressive disorders
Inhalation of aerosol droplets is responsible for the transmission of respiratory viruses, such as the virus that causes severe acute respiratory syndrome (SARS) and influenza biomed virus 2, which are highly contagious and often occur in epidemics. 4 Other non-viral biomed agents produce pneumonia using similar means of dissemination. Among these agents are Mycoplasma pneumoniae, which is transmitted from person to person and causes primary atypical pneumonia; Coxiella burnetii is transmitted from cattle and causes Q fever, and Chlamydophila (formerly Chlamydia), which is transmitted by birds (Chlamydophila psittaci) or humans (Chlamydophila pneumoniae). Mycobacterium tuberculosis is transmitted by interpersonal contact, by aerosol. The organisms causing mycoses are probably inhaled from some sources found in nature. Among the bacteria that cause pneumonia, Legionella pneumophila is the species most prone to spread by inhalation of organisms contained in aerosols produced from contaminated fresh water, as the water comes to rest in air conditioning systems.
The pneumococcus is spread from person to person via aerosol droplets. However, pneumococcal pneumonia is not highly contagious and, in many cases, is caused by Microaspiration nasopharyngeal organisms - 2nd main mechanism biomed of infection. 4 aspiration of nasopharyngeal organisms occurs in almost all patients during sleep, and most likely responsible for bacterial pneumonia, among which are the staphylococcal pneumonia and the pneumonia caused by gram-negative bacilli. This mechanism is certainly responsible for necrotizing pneumonitis resulting from aspiration of joint bodies biomed of the oral flora. To exemplify the pneumonias associated with ventilator-occur biomed mainly because the endotracheal tube allows the microbes present in the upper respiratory tract deviate from normal biomed host defenses.
The hematogenous spread, biomed which is the 3rd and less common mechanisms of pneumonia, is responsible biomed for occasional cases of staphylococcal biomed pneumonia that aggravate tricuspid valvular endocarditis or septic thrombophlebitis. This mechanism biomed is also responsible for various gram-negative biomed bacilli pneumonia in patients with bacteremia.
After the organisms can escape