title: Effects of imipenem, cefotaxime and cotrimoxazole on aerobic microbial colonization of the digestive tract.
abstract: Superinfections originating from a digestive tract colonized by abnormally high concentrations of aerobic microorganisms as a result of impaired resistance to colonization (CR) may complicate antibiotic therapy. In this study, patients with a moderate to severe systemic infection were randomized to receive either cefotaxime (CTX, n = 10) or cotrimoxazole (CTR, n = 10), 2 antibiotic regimens presumed to spare CR; or imipenem/cilastine (I/C, n = 19). The effect on CR was measured indirectly by comparing the aerobic faecal flora before antibiotic treatment with that on day 8 of treatment. An increase in aerobic faecal flora denotes a disturbed CR, whereas a decrease means that the organism is sensitive to the effective faecal concentration of the antibiotic. Imipenem/cilastine-treated patients showed a significant increase in enterococci and Candida spp., while the number of aerobic Gram-negative rods remained constant. Cefotaxime-treated patients had evidence of an increase in enterococci, but not of Candida spp., and Escherichia coli numbers decreased significantly. In these patients the concentration of other Gram-negative aerobic rods showed a slight increase in 6 patients with a resistant Pseudomonas strain. Cotrimoxazole-treated patients showed a significant decrease in aerobic Gram-negative rods, a significant increase in Candida spp. and no change in enterococci. It is concluded that all 3 antimicrobial agents impair colonization resistance. Whether or not this is followed by overgrowth with resistant micro-organisms depends on the active faecal concentration of the antimicrobial agent and the MIC of the aerobic micro-organisms. The risk of overgrowth of the bowel with resistant Gram-negative bacilli appears to be smaller following cotrimoxazole than following cefotaxime or imipenem/cilastine.
authors.affiliation: Department of Internal Medicine, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands.
authors.forename: J J
authors.initials: JJ
authors.lastname: Van der Leur
authors.forename: P L
authors.initials: PL
authors.lastname: Thunnissen
authors.forename: H A
authors.initials: HA
authors.lastname: Clasener
authors.forename: N F
authors.initials: NF
authors.lastname: Muller
authors.forename: A S
authors.initials: AS
authors.lastname: Dofferhoff
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001420:Bacteria, Aerobic / Q000187:drug effects* / Q000302:isolation & purification; D002175:Candida / Q000187:drug effects / Q000302:isolation & purification; D002439:Cefotaxime / Q000009:adverse effects*; D004064:Digestive System / Q000187:drug effects* / Q000382:microbiology*; D016983:Enterococcus / Q000187:drug effects / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D005260:Female; D006088:Gram-Negative Aerobic Bacteria / Q000187:drug effects / Q000302:isolation & purification; D006801:Humans; D015378:Imipenem / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D015163:Superinfection / Q000209:etiology / Q000382:microbiology; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000009:adverse effects*
chemical_list: D015378:Imipenem; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D002439:Cefotaxime