Levison M E, Kaye D
Rev Infect Dis. 1985 Nov-Dec;7 Suppl 4:S656-65. doi: 10.1093/clinids/7.supplement_4.s656.
Colonization of the oropharynx by Pseudomonas aeruginosa and enteric gram-negative bacilli in acutely ill or debilitated patients, alcoholics, diabetics, and persons with chronic bronchitis may lead to pneumonia. Although gram staining of sputum may provide immediate etiologic clues, the diagnosis is proven only by isolation of the pathogen from blood or pleural fluid or by various invasive techniques since expectorated specimens from highly susceptible patients are often contaminated with aerobic gram-negative bacilli colonizing the oropharynx. However, restricting the definition of cases to those involving empyema or bacteremia results in an underestimation of incidence. Combination therapy with a beta-lactam antibiotic plus an aminoglycoside is commonly recommended for gram-negative bacillary pneumonia because (1) the patients involved are usually debilitated and immunocompromised; (2) mortality is high; and (3) the spectrum of antibacterial activity is increased, emergence of resistance may be retarded, and synergistic activity may result. For example, a third-generation cephem antibiotic plus an aminoglycoside can be used for initial treatment of community-acquired gram-negative bacillary pneumonia, and piperacillin or azlocillin plus amikacin can be used for initial treatment of nosocomial infection in which P. aeruginosa or some other antibiotic-resistant gram-negative bacillus is more likely to be involved.
铜绿假单胞菌和肠道革兰氏阴性杆菌在急重症或身体虚弱的患者、酗酒者、糖尿病患者以及慢性支气管炎患者的口咽部定植，可能会导致肺炎。虽然痰液的革兰氏染色可能提供即时的病因线索，但只有通过从血液或胸腔积液中分离出病原体，或通过各种侵入性技术才能确诊，因为高度易感患者咳出的标本常被定植于口咽部的需氧革兰氏阴性杆菌污染。然而，将病例定义限制在那些涉及脓胸或菌血症的病例会导致发病率被低估。对于革兰氏阴性杆菌肺炎，通常推荐使用β-内酰胺类抗生素加氨基糖苷类抗生素联合治疗，原因如下：（1）所涉及的患者通常身体虚弱且免疫功能低下；（2）死亡率高；（3）抗菌活性谱增加，耐药性的出现可能会延迟，并且可能产生协同活性。例如，第三代头孢菌素抗生素加氨基糖苷类抗生素可用于社区获得性革兰氏阴性杆菌肺炎的初始治疗，哌拉西林或阿洛西林加阿米卡星可用于医院感染的初始治疗，在医院感染中更可能涉及铜绿假单胞菌或其他一些耐药革兰氏阴性杆菌。
