In vitro activity of rifaximin, metronidazole and vancomycin against Clostridium difficile and the rate of selection of spontaneously resistant mutants against representative anaerobic and aerobic bacteria, including ammonia-producing species

被引:94
作者
Marchese, A [1 ]
Salerno, A [1 ]
Pesce, A [1 ]
Debbia, EA [1 ]
Schito, GC [1 ]
机构
[1] Univ Genoa, Ist Microbiol CA Romanzi, I-16132 Genoa, Italy
关键词
rifaximin; spontaneous resistance; Clostridium difficile;
D O I
10.1159/000007297
中图分类号
R73 [肿瘤学];
学科分类号
100214 ;
摘要
Background: Rifaximin is a rifamycin derivative characterized by a wide antibacterial activity. This drug is neither absorbed by the gastrointestinal tract nor inactivated by gastric juices, and exerts its action entirely within the intestinal lumen. Methods: In this study, the activity of this antibiotic was compared with that of metronidazole and vancomycin against 93 Clostridium difficile isolates. The rate of emergence of bacteria spontaneously resistant to the new compound was also evaluated in relation to representative gram-positive and gram-negative strains. In terms of MIC50 values, rifaximin showed an intrinsic activity superior to that of the other agents. The emergence of spontaneously resistant strains was assessed with 46 aerobic (staphylococci, enterococci, Proteus spp., Citrobacter freundii, Providencia rettgeri, enteropathogenic, enteroinvasive, enterotoxigenic and enterohemorrhagic Escherichia coli, and Salmonella enteritidis) and anaerobic (Clostridium spp., Bacteroides spp., Fusobacterium nucleatum and Peptococcus spp.) pathogens, most of them also ammonium producers. Two different methods, broth and agar dilution, were employed. Results: When liquid medium was employed, bacteria capable of sustained growth in 100 mu g/ml of rifaximin were obtained after 2-5 transfers with grampositive aerobic cocci, 2-3 transfers with gram-negative aerobic strains and 2-5 transfers with anaerobic species. At the highest dose used with the agar dilution method (8 x MIG), the frequency of emergence of spontaneously resistant mutants ranged from <1 x 10(-9) to 1.6 x 10(-8) With gram-positive aerobic and anaerobic cocci, while with aerobic and anaerobic gram-negative bacteria, this value ranged from <1 x 10(-9) to 1.7 x 10(-7). C. difficile showed a particularly low incidence of spontaneously resistant mutants (<1 x 10(-9)). The low incidence of resistant subpopulations selected by levels of 8 x MIC of rifaximin suggests that the high levels of the drug which were reached in the gastrointestinal lumen may further prevent the selection of mutants. Conclusion: The low toxicity, broad antibacterial activity and very poor absorption from the gastrointestinal tract of rifaximin suggest a potential therapeutic use for this drug in gastrointestinal diseases, as well as in the management of patients with cirrhosis and chronic portal-systemic encephalopathy. Copyright (C) 2000 S. Karger AG, Basel.
引用
收藏
页码:253 / 266
页数:14
相关论文
共 30 条
[1]   RIFAXIMIN, A RIFAMYCIN DERIVATIVE FOR USE IN THE TREATMENT OF INTESTINAL BACTERIAL-INFECTIONS IN SERIOUSLY DISABLED PATIENTS [J].
ALVISI, V ;
DAMBROSI, A ;
LOPONTE, A ;
PAZZI, P ;
GRECO, A ;
ZANGIROLAMI, A ;
PALAZZINI, E .
JOURNAL OF INTERNATIONAL MEDICAL RESEARCH, 1987, 15 (01) :49-56
[2]  
CELLAI L, 1984, CHEMIOTERAPIA, V3, P373
[3]   BIOCHEMICAL-MECHANISMS OF HEPATIC-ENCEPHALOPATHY [J].
CROSSLEY, IR ;
WARDLE, EN ;
WILLIAMS, R .
CLINICAL SCIENCE, 1983, 64 (03) :247-252
[4]   PROGRESS IN THE TREATMENT OF CHRONIC PORTASYSTEMIC ENCEPHALOPATHY [J].
CROSSLEY, IR ;
WILLIAMS, R .
GUT, 1984, 25 (01) :85-98
[5]  
DEBBIA EA, 1992, DRUG EXP CLIN RES, V18, P129
[6]  
DELEO C, 1986, DRUG EXP CLIN RES, V12, P979
[7]  
DESCOMBE JJ, 1994, INT J CLIN PHARM RES, V14, P51
[8]  
EFTIMIADI C, 1984, DRUG EXP CLIN RES, V10, P691
[9]  
FEKETY R, 1995, PRINCIPLES PRACTICE, P978
[10]  
GEMMEL GC, 1996, ANTIBIOTICS LAB MED, P397