Is over-use of proton pump inhibitors fuelling the current epidemic of Clostridium difficile-associated diarrhoea?

Many developed countries have seen an increase in cases of Clostridium difficile-associated diarrhoea (CDAD) in recent years. This has occurred despite heightened awareness of the risks of broad-spectrum antibiotics, overall reduction in antibiotic use and increased focus on hospital hygiene. Some of the increase is due to the introduction of new hypervirulent strains, but it predates the description of these. The epidemic coincides with increased use of proton pump inhibitors (PPIs), much of which is inappropriate according to UK and other national guidelines. Gastric acid is a key host defence against other gastrointestinal infections and epidemiological and animal studies have demonstrated a positive association between incident CDAD and PPI use. An association with recurrence of CDAD after initially successful treatment has also been found. Vegetative C. difficile cells are rapidly killed at normal gastric pH, but survive at the pH found in patients taking PPI. It has recently been shown that vegetative organisms survive long enough on moist surfaces for transmission between patients to occur. We conclude that restricting PPI use to patients with an appropriate indication would reduce unnecessary expenditure on these agents, and might be an additional means of controlling the current epidemic of CDAD.

Clostridium difficile infections in a Canadian tertiary care hospital before and during a regional epidemic associated with the BI/NAP1/027 strain

Since 2002, an epidemic of Clostridium difficile infections has occurred in southern Quebec, Canada. At Hôpital Maisonneuve-Rosemont, Montreal, Quebec, Canada, the incidence of C. difficile infections increased from 11/1,000 admissions (1999 to 2002) to 27/1,000 admissions (2003 to 2005). We compared the exposures and outcomes for patients infected with strains with different ribopatterns isolated before (n = 55) and during (n = 175) the epidemic, as well as the in vitro activities of antibiotics against those isolates. During the preepidemic period, 46 isolates (84%) were of ribotype 001, 1 was of ribotype 027, and 8 were of other ribopattern types. During the epidemic period, ribotype 027 strains accounted for 140 (80%) isolates; 26 (15%) were of ribotype 001, and 7 were of other ribopattern types. Ribotype 027 strains were highly resistant to fluoroquinolones (FQs) but were susceptible to clindamycin. A pattern of prior specific antibiotic exposure that selected for antibiotic-resistant ribotype C. difficile infections was observed for FQs (ribotype 027) and clindamycin (ribotype 001). The rate of mortality was higher among older patients, those with a high Charlson comorbidity index, and those with longer previous hospitalizations. By multivariate analysis, patients infected with ribotype 027 were twice as likely to die within 30 days of diagnosis than patients infected with other ribotypes (adjusted odds ratio, 2.06; 95% confidence interval, 1.00 to 4.22). The observations from this study support the notion that continued selective antibiotic pressure resulted in the superimposition of the hypertoxigenic ribotype 027 clone on top of the prior dominant ribotype 001 clone in a setting of preexisting high endemicity, thus leading to the high rates of morbidity and mortality seen in the Quebec outbreak. Stringent antibiotic stewardship measures, combined with aggressive infection control, are required to curtail the epidemic of C. difficile infections.