Can antibiotics be effective in preventing travellers’ diarrhoea?

There’s nothing more exciting than packing your bags and jetting off to some far flung destination for a bit of adventure. I’m even thinking of taking my-elf off to the Woodland beyond the cornfield next year – it’s Woodland but not as we know it. A little part of me is a bit concerned about getting poorly while I’m there. Consuming food and water that I’m not used to, the possibility of it being contaminated and ending up with the dreaded Delhi belly.

Infections of predominantly bacterial origin can cause severe illness and discomfort known as travellers’ diarrhoea (TD).  It afflicts thousands of travellers and disrupts many business and leisure trips. TD can also lead to long-term health problems such as post infectious irritable bowel syndrome (PI-IBS).  For that reason research has focused on primary disease prevention – not easy to do because of the unhygienic conditions often seen in less developed countries.

Antibiotic (Ab) chemoprophylaxis (administering medicine to prevent infection) is one avenue that has been explored in the past – for many years thought not to be a universal treatment option due to concern about the development of Ab resistant strains of bacteria. More recently though, rifaximin, a non-absorbable Ab has been produced that could be a safer alternative than the currently used fluoroquinolones (used for high-risk groups only).

A systematic review has been carried out designed to look at the effectiveness of rifaximin and fluoroquinolone Abs in preventing TD. After a search of relevant databases and including randomised, placebo-controlled and double blind studies they identified nine (5 fluoroquinolone and 4 rifaximin) studies involving 1310 subjects for their analysis. The duration of intervention on average was 14 days. A meta-analysis of the studies was carried out and this is what they found:

  • Among the rifaximin studies the relative risk (RR) estimate was 0.33% (95% CI=0.24 to 0.45), equating to a protective efficacy of 67% (95% CI=55% to 76%) favouring chemoprophylaxis
  • Absolute risk reduction analysis equated to a number needed to treat (NNT) of 4.5 people (95%CI= 2.6 to 15.9) who needed rifaximin chemoprophylaxis to prevent one episode of TD
  • The fluoroquinolone studies showed a RR estimate of 0.12 (95%CI=0.07 to 0.20), equating to a protective efficacy of 88% (95%CI=80% to 93%) favouring chemoprophylaxis
  • Absolute risk reduction analysis equated to a NNT of 2.8 people (95% CI=2.0 to 4.7) who needed fluoroquinolone chemoprophylaxis to prevent one episode of TD

But:

  • There are a small number of studies and a lack of studies conducted among a variety of population types and geographic regions
  • There was incomplete data reporting from some of the studies
  • The studies examining fluoroquinolones were not as current as the rifaximin studies.  Due to resistant bacterial strains developing it would be useful to have more recent data for this Ab
  • Although the meta-analysis indicates that the Abs are effective at preventing TD and rifaximin is a safer alternative, there is still consensus against the widespread use of Ab chemoprophylaxis.  Many Doctors believe that rapid and judicious treatment of diarrhea is the best recommendation for travellers

The authors concluded:

‘..the recognition of both the acute and chronic consequences associated with TD diarrhea may change the risk balance and value equation for antibiotic chemoprophylaxis’

‘If a traveller is planning on taking a short-term trip (<14 days in duration) to an area where the risk for developing TD is high and diarrheagenic E.Coli pathogens predominate, the data reviewed in this study supports the author’s opinion that routine chemoprophylaxis with rifaximin may be a reasonable choice if the patient does not have any contraindications for use’

I think it’s fair to say we’ve probably all been afflicted at some time or other by this crappy (pardon the pun) condition. Bloated and full of cramps you end up mentally calculating the location of every bathroom within a 1 mile radius.  When you gotta go, you gotta go! f you’re at high risk it looks like a safer alternative than fluoroquinolone might be round the corner.

Link:

Alajbegovic et al.: Effectiveness of rifaximin and fluoroquinolones in preventing travelers’ diarrhea (TD): a systematic review and meta-analysis. Systematic Reviews 2012 1:39