Enteroaggregative Escherichia coli diarrhea in travelers: response to rifaximin therapy

Infante, Rosa; Ericsson, Charles D.; Jiang, Zhi; Shi, Ke; Steffen, Robert; Riopel, Lise; Sack, David A.; DuPont, Herbert L.

doi:10.1016/s1542-3565(03)00322-7

Cited by 46 publications

(33 citation statements)

References 26 publications

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“…Enteroaggregative Escherichia coli (EAEC), first identified and described as diarrheagenic E. coli in 1987 (29), has emerged as a leading cause of acute and persistent (Ն14 days) diarrhea among children, patients with AIDS, and international travelers in developing and industrialized countries (2,9,19,25,36). Around the world, EAEC accounts for 8 to 32% of acute diarrhea cases among infants and children and 20 to 30% of persistent diarrhea cases (17).…”

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confidence: 99%

Nitazoxanide Inhibits Biofilm Production and Hemagglutination by Enteroaggregative Escherichia coli Strains by Blocking Assembly of AafA Fimbriae

Shamir

Warthan

Brown

et al. 2010

Antimicrob Agents Chemother

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Enteroaggregative Escherichia coli (EAEC) strains have emerged as common causes of persistent diarrhea and malnutrition among children and HIV-infected persons. During infection, EAEC typically adheres to the intestinal mucosa via fimbrial adhesins, which results in a characteristic aggregative pattern. In the study described here we investigated whether the broad-spectrum antiparasitic and antidiarrheal drug nitazoxanide (NTZ) might be active against EAEC in vitro. While E. coli strains were resistant to NTZ in rich Luria-Bertani medium (MIC > 64 g/ml), the drug was slightly inhibitory in a minimal medium supplemented with glucose (MinA-G medium; MIC, ϳ32 g/ml). NTZ also inhibited biofilm production by strain EAEC 042 in both Dulbecco's modified Eagle's medium and MinA-G medium with a 50% inhibitory concentration of ϳ12 g/ml.Immunofluorescence and immunoblot analyses with antibody against the major fimbrial subunit AafA of aggregative adherence fimbriae vaariant II (AAF/II) established that the numbers of AAF/II filaments on bacteria grown in the presence of NTZ were dramatically reduced. Comparative quantitative reverse transcription-PCR and reporter gene fusions (aafA::phoA) indicated that aafA expression was unaffected by NTZ, while aggR transcript levels and aggR::lacZ expression were increased ϳ10-and 2.5-fold, respectively, compared with that for the untreated controls. More generally, NTZ inhibited hemagglutination (HA) of red blood cells by the non-biofilm-producing strain JM221 expressing either AAF/I or type I fimbriae. Our findings suggest that the inhibitory action of NTZ on biofilm formation and HA is likely due to inhibition of fimbrial assembly. Antimicrobial agents that inhibit the assembly or function of fimbrial filaments should be good candidates for the prevention of infection.

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Nitazoxanide Inhibits Biofilm Production and Hemagglutination by Enteroaggregative Escherichia coli Strains by Blocking Assembly of AafA Fimbriae

Shamir

Warthan

Brown

et al. 2010

Antimicrob Agents Chemother

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“…Rifaximin is a semisynthetic rifamycin derivative that has been safely and successfully used to treat and prevent traveler's diarrhea (6,7,13,26). Rifaximin's additional pyridoimidazole ring makes it virtually nonabsorbable (Ͻ0.4%), leading to high concentrations of the drug in feces after oral administration (15).…”

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“…The mechanism(s) of action of rifaximin in these diverse conditions remains poorly defined. Rifaximin has been shown to have effects on gene-regulatory pathways in mammalian cells (13,14), suggesting that the drug may have effects on mammalian cells independent of its antimicrobial properties. Furthermore, rifaximin is a unique antibiotic in several ways: (i) bacterial pathogens show a low potential for developing resistance during rifaximin therapy, in contrast to the situation with the structurally related drug rifampin (4); (ii) following oral administration, the drug has little effect on Gram-negative coliforms in the gut or on Gram-positive enterococcal flora (7,8); (iii) the drug ameliorates diarrheal disease symptoms, often without significant alteration to the intestinal pathogen burden or the counts of intestinal flora (1,7,8), even though rifaximin concentrations can reach ϳ8,000 g/g of stool after 3 days of treatment (15).…”

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Pretreatment of Epithelial Cells with Rifaximin Alters Bacterial Attachment and Internalization Profiles

Brown

Xue²,

Jiang

et al. 2010

Antimicrob Agents Chemother

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“…Of note, our study included only 23 EAEC samples, and thus, more strains are needed to further determine antimicrobial resistance among EAEC strains. RIF was the only antibiotic that remained active against EAEC strains, and the drug has been shown to effectively treat EAEC diarrhea in travelers (15).…”

Section: Discussionmentioning

confidence: 99%

In Vitro Antimicrobial Susceptibility of Bacterial Enteropathogens Isolated from International Travelers to Mexico, Guatemala, and India from 2006 to 2008

Ouyang-Latimer

Jafri

VanTassel

et al. 2011

Antimicrob Agents Chemother

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The incidence rates of travelers' diarrhea (TD) have remained high for the last 50 years. More recently, there have been increasing recommendations for self-initiated therapy and use of prophylactic drugs for TD. We last examined the in vitro susceptibilities of commonly used antibiotics against TD pathogens in 1997. We now examine 456 enteropathogens isolated from adult travelers to Mexico, India, and Guatemala with diarrhea acquired between 2006 and 2008 to determine changes in susceptibility against 10 different antimicrobials by the agar dilution method. Traditional antibiotics, such as ampicillin, trimethoprim-sulfamethoxazole, and doxycycline, continue to show high levels of resistance. Current first-line antibiotic agents, including fluoroquinolones and azithromycin, showed significantly higher MICs than in our earlier study, and MIC 90 levels were above the Clinical and Laboratory Standards Institute cutoffs for resistance. There were significant geographical differences in resistance patterns when Central America was compared with India. Entertoxigenic Escherichia coli (ETEC) isolates showed increased resistance to ciprofloxacin (P ‫؍‬ 0.023) and levofloxacin (P ‫؍‬ 0.0078) in India compared with Central America. Enteroaggregative E. coli (EAEC) isolates from Central America showed increased resistance to nearly all of the antibiotics tested. Compared to MICs of isolates 10 years prior, there were 4-to 10-fold increases in MIC 90 values for ceftriaxone, ciprofloxacin, levofloxacin, and azithromycin for both ETEC and EAEC. There were no significant changes in rifaximin MICs. Rising MICs over time imply the need for continuous surveillance of susceptibility patterns worldwide and geographically specific recommendations in TD therapy.

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Enteroaggregative Escherichia coli diarrhea in travelers: response to rifaximin therapy

Cited by 46 publications

References 26 publications

Nitazoxanide Inhibits Biofilm Production and Hemagglutination by Enteroaggregative Escherichia coli Strains by Blocking Assembly of AafA Fimbriae

Nitazoxanide Inhibits Biofilm Production and Hemagglutination by Enteroaggregative Escherichia coli Strains by Blocking Assembly of AafA Fimbriae

Pretreatment of Epithelial Cells with Rifaximin Alters Bacterial Attachment and Internalization Profiles

In Vitro Antimicrobial Susceptibility of Bacterial Enteropathogens Isolated from International Travelers to Mexico, Guatemala, and India from 2006 to 2008

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