Saunders G L, Hammond J M, Potgieter P D, Plumb H A, Forder A A
Department of Medical Microbiology, Groote Schurr Hospital, Observatory, South Africa.
J Antimicrob Chemother. 1994 Oct;34(4):529-44. doi: 10.1093/jac/34.4.529.
The use of selective decontamination of the digestive tract (SDD) as prophylaxis against nosocomial respiratory tract infection remains controversial, largely because of concerns that, in the long term, it may promote the emergence of antibiotic-resistant strains. This report describes the results of surveillance cultures and susceptibility testing undertaken during the course of a 2-year, double-blind study of the efficacy of SDD which was conducted in a respiratory intensive care unit (ICU). Surveillance specimens from the alimentary tract and trachea were obtained from each patient on admission and then twice weekly until 48 h after discharge from the unit. Specimens were cultured semiquantitatively and organisms from morphologically distinct colonies were identified by standard methods; the susceptibilities of these isolates were determined by the disc diffusion method. Five thousand, nine hundred and sixty surveillance samples from 239 patients were processed in this way. Compared with the placebo group, SDD caused a significant reduction in the incidence of colonization of the alimentary tract with aerobic Gram-negative bacilli (AGNB), and Candida spp. were almost totally eliminated. The incidence of colonization with enterococci increased in both groups, while the incidence of both colonization of the alimentary tract with strains of coagulase-negative staphylococci and methicillin-resistant Staphylococcus aureus and infection caused by these organisms increased in the SDD group. Acinetobacter spp. were the most common bacteria associated with unit-acquired colonization and lower respiratory tract infection in both groups. The acquisition of strains of Pseudomonas aeruginosa and cefotaxime- and/or tobramycin-resistant Enterobacteriaceae was significantly greater in the placebo group than in the SDD group, although tobramycin-resistant strains of Proteus, Morganella and Providencia spp. were isolated from three of 114 patients receiving SDD. The use of SDD did not lead to an overall increase in antibiotic resistance amongst the AGNB usually associated with ICU-acquired infection. However, colonization with strains which were either resistant to one or more of the antibiotic components of the regimen or which were not inhibited by the regimen was observed and may subsequently lead to infection.
使用消化道选择性去污（SDD）预防医院获得性呼吸道感染仍存在争议，主要是因为担心从长远来看，它可能会促进耐药菌株的出现。本报告描述了在呼吸重症监护病房（ICU）进行的一项为期2年的SDD疗效双盲研究过程中进行的监测培养和药敏试验结果。在每位患者入院时从消化道和气管获取监测标本，然后每周两次，直至从该病房出院后48小时。标本进行半定量培养，通过标准方法鉴定形态学上不同菌落的微生物；这些分离株的药敏性通过纸片扩散法测定。以这种方式处理了来自239名患者的5960份监测样本。与安慰剂组相比，SDD导致需氧革兰氏阴性杆菌（AGNB）和念珠菌属在消化道定植的发生率显著降低，念珠菌属几乎完全消除。两组肠球菌定植的发生率均增加，而SDD组中凝固酶阴性葡萄球菌和耐甲氧西林金黄色葡萄球菌在消化道定植的发生率以及由这些微生物引起的感染发生率均增加。不动杆菌属是两组中与医院获得性定植和下呼吸道感染相关的最常见细菌。安慰剂组中铜绿假单胞菌菌株以及对头孢噻肟和/或妥布霉素耐药的肠杆菌科细菌的获得显著高于SDD组，尽管在接受SDD的114名患者中有3名分离出了对妥布霉素耐药的变形杆菌属、摩根菌属和普罗威登斯菌属菌株。使用SDD并未导致通常与ICU获得性感染相关的AGNB中抗生素耐药性总体增加。然而，观察到存在对该方案的一种或多种抗生素成分耐药或不受该方案抑制的菌株定植，随后可能导致感染。
