Visscher Stefan, Schurink Carolina A M, Melsen Wilhelmina G, Lucas Peter J F, Bonten Marc J M
Department of Internal Medicine & Infectious Diseases, University Medical Center Utrecht, Utrecht, The Netherlands.
Intensive Care Med. 2008 Apr;34(4):692-9. doi: 10.1007/s00134-007-0984-5. Epub 2008 Jan 8.
Bacterial respiratory tract colonization predisposes critically ill patients to intensive care unit (ICU)-acquired infections. It is unclear to what extent systemic antibiotics affect colonization persistence. Persistence of respiratory tract colonization, and the effects of systemic antibiotics hereon, were determined in a cohort of ICU patients.
Clinical and microbiological data were collected from 715 admitted mechanically ventilated ICU patients with bacterial growth documented in respiratory tract samples. First day of colonization, persistence of colonization and antibiotic effects hereon were analyzed for six groups of pathogens: Pseudomonas aeruginosa, Acinetobacter species, Enterobacteriaceae, Staphylococcus aureus, Streptococcus pneumoniae and Haemophilus influenzae. Systemic antibiotics were grouped into 'effective' and 'ineffective' antibiotics, based on in-vitro susceptibility data for the relevant bacteria. The effects of antibiotics were quantified as relative risk (RR) of bacterial persistence in the absence of effective antibiotics.
Persistence of colonization differed significantly between pathogens, ranging from 4 days (median) for H. influenzae and Strep. pneumoniae to 8 days for P. aeruginosa. Systemic antibiotics were administered on 7,102 (61%) of patient days. Antibiotic use was associated with non-persistence for all pathogens, except Acinetobacter species and P. aeruginosa. RR for non-persistence (as compared to ineffective or no antibiotics) ranged from 3.1 (95% CI 1.4-6.6) for H. influenzae to 0.5 (0.3-1.0) for Acinetobacter species.
In mechanically ventilated patients, persistence dynamics of bacterial respiratory tract colonization, and the effects of (in-vitro) effective antibiotics hereon, are pathogen-specific.
细菌呼吸道定植使重症患者易发生重症监护病房（ICU）获得性感染。目前尚不清楚全身使用抗生素在多大程度上会影响定植的持续存在。本研究在一组ICU患者中确定了呼吸道定植的持续情况以及全身使用抗生素对此的影响。
收集了715例入住ICU且机械通气、呼吸道样本中有细菌生长记录的患者的临床和微生物学数据。对六组病原体（铜绿假单胞菌、不动杆菌属、肠杆菌科、金黄色葡萄球菌、肺炎链球菌和流感嗜血杆菌）分析了定植的第一天、定植的持续情况以及抗生素对此的影响。根据相关细菌的体外药敏数据，将全身使用的抗生素分为“有效”和“无效”抗生素。抗生素的影响以无有效抗生素时细菌持续存在的相对风险（RR）来量化。
不同病原体的定植持续时间差异显著，流感嗜血杆菌和肺炎链球菌的中位数为4天，铜绿假单胞菌为8天。在7102个（61%）患者日使用了全身抗生素。除不动杆菌属和铜绿假单胞菌外，使用抗生素与所有病原体的非持续性相关。非持续性的RR（与无效或未使用抗生素相比）范围从流感嗜血杆菌的3.1（95%CI 1.4 - 6.6）到不动杆菌属的0.5（0.3 - 1.0）。
在机械通气患者中，细菌呼吸道定植的持续动态以及（体外）有效抗生素对此的影响具有病原体特异性。
