Traveler’s diarrhea

Bacteria are likely precipitants in many other cases including Escherichia coli, Salmonella species, Shigella species, Vibrio cholerae, and Clostridium difficile. The term dysentery has often been used to describe some of these bacterial infections when associated with serious occurrences of bloody diarrhea. Additionally, acute diarrheal conditions can be prompted by parasites-protozoa such as Entamoeba histolytica, Microsporidium, Giardia lamblia, and Cryptosporidium parvum. Most of these infectious agents can be causes of traveler s diarrhea, a common malady alflicting travelers worldwide. It usually occurs during or just after travel subsequent to the ingestion of fecally-contaminated food or water. It has an abrupt onset but usually subsides within 2 to 3 days. 

Although diarrhea can often be attributed to a specific mechanism, some patients develop diarrhea due to overlapping mechanisms. For example, malabsorption syndromes and traveler s diarrhea are associated with both secretory and osmotic diarrhea. 

Empiric antibiotic therapy is an appropriate approach to traveler s diarrhea. Eradication of the causal microbe depends on the etiologic agent and its antibiotic sensitivity. Most cases of traveler s diarrhea and other community-acquired infections result from enterotoxigenic (ETEC) or enteropathogenic (EPEC) Escherichia coli. Routine stool cultures do not identify these strains primary empiric antibiotic choices include fluoroquinolones such as ciprofloxacin or levofloxacin. Azithromycin may be a feasible option when fluoroquinolone resistance is encountered. 

Adachi JA, Ostrosky-Zeichner L, DuPont HL, Ericsson CD Empirical antimicrobial therapy for traveler s diarrhea. Clin Infect Dis 2000 31 1079-1083. 

DuPont HL, Ericsson CD Prevention and treatment of traveler s diarrhea. N Engl J Med 1993 328 1821-1827. 

Gorbach SL, Edelman R Traveler s diarrhea National Institutes of Health Consensus Conference. JAMA 1985 253 2700-2704. 

DuPont HL, Jiang ZD, Ericsson CD, Adachi JA, Mathewson JJ, DuPont MW, Palazzini E, Riopel LM, Ashley D, Martinez-Sandoval F Rifaximin versus ciprofloxacin for the treatment of traveler s diarrhea A randomized, double-blind clinical trial. Clin Infect Dis 2001 33 1807-1815. 

Rifaximin is available in Europe for the treatment of acute intestinal bacterial infections, hepatic encephalopathy, bacterial overgrowth syndrome, diverticular disease of the colon, and for the prevention of infections after colorectal surgery [3, 4]. Rifaximin is also licensed in Mexico, Asia and Northern Africa and has recently been approved in USA for the treatment of traveler s diarrhea. 

Adachi J, Jiang ZD, Mathewson JJ, Verenkar MP, Thompson S, Martinez-Sandoval F, Steffen R, Ericsson CD, DuPont HL Enteroaggre-gative Escherichia coli as a major etiologic agent in traveler s diarrhea in 3 regions of the world. Clin Infect Dis 2001 32 1706-1709. 

Sierra JM, Ruiz J, Navia MM, Vargas M, Gascon J, Vila J In vitro activity of rifaximin against enteropathogens producing traveler s diarrhea. Antimicrob Agents Chemother 2001 45 643-644. 

While in patients with traveler s diarrhea due to E. coli the efficacy of the antibiotic was uniformity high, the cure rate was significantly lower when invasive pathogens (e.g. Campylobacter jejuni) causing fever and/or dysentery were present (DuPont, unpublished observations). 

After the submission of this paper several publications have appeared in the literature that reinforce the role of rifaximin in the treatment of infectious diarrhea [1]. An entire issue of the Journal of Travel Medicine devoted to the use of this antibiotic in the treatment of traveler s diarrhea (TD) has been published [2-5], In addition, a recent paper from our laboratory [6] confirmed the rifaximin efficacy also in enteroaggregative Escherichia coli-mediated TD. Furthermore, in a randomized, double-blind, placebo-con-trolled study [7] even once daily administration of the antibiotic proved to be capable of preventing TD. Finally, Lawler and Wallace [8] recently reviewed the treatment options for bacterial diarrhea and considered rifaximin a useful addition to our therapeutic armamentarium. 

Diarrhea is a well-known complication of antibiotic therapy. Rates of antibiotic-associated diarrhea (AAD) vary from 5 to 25%. Some antibiotics are more likely to cause diarrhea than others, specifically, those that are broad spectrum and those that target anaerobic flora. This paper reviews the effects of antibiotics on the fecal flora as well as host factors which contribute to AAD. Clinical features and treatment of AAD are also described. Prevention of AAD rests on wise antibiotic policies, the use of probiotics and prevention of acquisition in the hospital setting. Data from clinical trials suggest that poorly absorbed antimicrobials might have a decreased risk of causing AAD and Clostridium difficile-associated disease, as concluded from studies of antibiotics used for preoperative bowel decontamination and poorly absorbed antibiotics used for traveler s diarrhea. Controlled trials would prove this but are not yet available. Probiotics may be a good adjunct to poorly absorbed antibiotics to minimize the risk of diarrhea associated with antibiotics. 

Nonabsorbable antibiotics are appealing because they have fewer systemic side effects and may be safer for children and pregnant women as well as in patients with renal and hepatic dysfunction. One such antibiotic, aztreonam, showed little effect on anaerobic flora in human volunteers, producing most of its effect on the aerobic flora [49, 50], A trial showed efficacy of aztreonam for traveler s diarrhea, where most pathogens are aerobes [51]. While there are no data on rates of AAD for nonabsorbable antibiotics and C. difficile, these would likely be decreased. Given the preservation of the anaerobic flora, another poorly absorbed antibiotic, bicozamycin, has efficacy in traveler s diarrhea with its major effect being on fecal aerobes [52],... 

Ericsson CD, DuPont HL, Sullivan P, Galindo E, Evans DG, Evans DJ Bicozamycin, a poorly absorbable antibiotic, effectively treats traveler s diarrhea. Ann Intern Med 1983,98 20-25. 

Bismuth subsalicylate is often used for treatment or prevention of diarrhea (traveler s diarrhea) and has antisecretory, antiinflammatory, and antibacterial effects. Bismuth subsalicylate contains multiple components that might be toxic if given in excess to prevent or treat diarrhea. 

Escherichia coli GI disease may be caused by enterotoxigenic E. coli (ETEC), enteroinvasive E. coli, enteropathogenic E. coli, enteroadhesive E. coli, and enterohemorrhagic E. coli. ETEC is now incriminated as being the most common cause of traveler s diarrhea. 

ADP-ribosylation by Cholera toxin E. coli toxin Pertussis toxin G a Gjffl Diarrhea of cholera Traveler s diarrhea Pertussis (whooping cough)... 

Certain strains of Escheridiia coli release toxins similar to cholera toxin, producii traveler s diarrhea. 

Another group of compounds, the tetracyclines, are made by fermentation procedures or by chemical modifications of the natural product. The hydrochloride salts are used most commonly for oral administration and are usually encapsulated because of their bitter taste. Controlled catalytic hydrogenolysis of chlortetracycline, a natural product, selectively removes the 7-chloro atom and produces tetracycline. Doxycycline and minocycline are other important antibacterials. Tetracycline can be prescribed for people allergic to penicillin. Doxycycline prevents traveler s diarrhea. Tetracyclines help many infections including Rocky Mountain spotted fever, Lyme disease, urinary tract infections, bronchitis, amoebic dysentery, and acne. 

OTC Control of symptoms of diarrhea, including traveler s diarrhea. 

For indigestion without causing constipation nausea control of diarrhea, including traveler s diarrhea, within 24 hours. Also relieves abdominal cramps. 

TMP-SMX is also used in the treatment of infection caused by ampicillin-resistant Shigella spp. and for antibiotic-resistant Salmonella spp.. The combination is also effective for covering the carrier state of Salmonella typhi, the agent of typhoid fever, and other Salmonella spp.. Successful treatment of traveler s diarrhea due to susceptible E. coli is another advantage of the use of this combination. The combination is not indicated in the therapy of enterohemorrhagic E. coli strains such as 0157 H7 because of the risk of developing hemolytic-uremic syndrome associated with the release of the cytotoxic enterotoxin by the drugs. 

Traveler s diarrhea PO 1 double-strength or 2 single-strength tablets or 20-ml suspension q 12h for 5 days. 

Traveler s diarrhea PO 100 mg/day during a period of risk (up to 14 days) and for 2 days after returning home. 

Uniabeled Uses Treatment of atypical mycobacterial infections, gonorrhea, malaria, rheumatoid arthritis prevention of Lyme disease prevention or treatment of traveler s diarrhea. 

Traveler s diarrhea PO Initially 4 mg then 2 mg after each loose bowel movement (LBM). Maximum 8 mg/day for 2 days. 

---