Proton pump inhibitors (PPIs) are associated with the development of Clostridium difficile infection in humans. Though it is assumed that PPIs mediate this effect through gastric acid suppression, there has been little investigation into whether PPIs, or ambient pH, might directly affect the expression of C. difficile toxin genes. In the present study, C. difficile ribotypes 001, 027 and 078 obtained from human subjects were grown under anaerobic conditions prepared at pHs of 5, 7.3 and 9. Matched trios were exposed to 100 µM and 200 µM of omeprazole along with PPI untreated controls. Custom designed reverse transcription quantitative PCR hydrolysis probes were used to assess C. difficile gene expression for toxins A (tcdA), B (tcdB) and binary toxin (cdtB), as well as their positive regulators (tcdR and cdtR), using rrsA, which encodes 16S rRNA, as a constitutively expressed reference gene. tcdC and codY, negative regulators of toxin expression, were also assessed. Basic pH resulted in greater expression of tcdA, and with PPI exposure a 120-fold higher expression was noted with ribotype 001. tcdB and cdtB expressions were much less responsive to pH or PPIs, though a clear response to acidic pH and PPI exposure was observed in ribotype 027. tcdC and codY expressions were largely unaffected, except with ribotype 027; low pH and PPIs resulted in their greater expression, though to a lesser degree than with toxin genes and their positive regulators. Non-neutral pH and PPI exposure appear to have an effect on C. difficile, one that has a net effect towards toxin gene expression.
AkhtarA. J., ShaheenM.2007; Increasing incidence of clostridium difficile-associated diarrhea in African-American and Hispanic patients: association with the use of proton pump inhibitor therapy. J Natl Med Assoc 99:500–504[PubMed]
AseeriM., SchroederT., KramerJ., ZackulaR.2008; Gastric acid suppression by proton pump inhibitors as a risk factor for Clostridium difficile-associated diarrhea in hospitalized patients. Am J Gastroenterol 103:2308–2313 [View Article][PubMed]
BavishiC., DupontH. L.2011; Systematic review: the use of proton pump inhibitors and increased susceptibility to enteric infection. Aliment Pharmacol Ther 34:1269–1281 [View Article][PubMed]
BustinS. A., BenesV., GarsonJ. A., HellemansJ., HuggettJ., KubistaM., MuellerR., NolanT., PfafflM. W.other authors2009; The MIQE guidelines: minimum information for publication of quantitative real-time PCR experiments. Clin Chem 55:611–622 [View Article][PubMed]
ChoungR. S., LockeG. R., SchleckC. D., ZinsmeisterA. R., TalleyN. J.2013; Associations between medication use and functional gastrointestinal disorders: a population-based study. Neurogastroenterol Motil 25:413–e298 [View Article][PubMed]
CloudJ., NoddinL., PressmanA., HuM., KellyC.2009; Clostridium difficile strain NAP-1 is not associated with severe disease in a nonepidemic setting. Clin Gastroenterol Hepatol 7:868–873, e2 [View Article][PubMed]
FraeymanJ., Van HalG., GodmanB., BeutelsP.2013; The potential influence of various initiatives to improve rational prescribing for proton pump inhibitors and statins in Belgium. Expert Rev Pharmacoecon Outcomes Res 13:141–151 [View Article][PubMed]
LeonardJ., MarshallJ. K., MoayyediP.2007; Systematic review of the risk of enteric infection in patients taking acid suppression. Am J Gastroenterol 102:2047–2056, quiz 2057 [View Article][PubMed]
McGinnD., GodmanB., LonsdaleJ., WayR., WettermarkB., HaycoxA.2010; Initiatives to enhance the quality and efficiency of statin and PPI prescribing in the UK: impact and implications. Expert Rev Pharmacoecon Outcomes Res 10:73–85 [View Article][PubMed]
MirshahiF., FowlerG., PatelA., ShawG.1998; Omeprazole may exert both a bacteriostatic and a bacteriocidal effect on the growth of Helicobacter pylori (NCTC 11637) in vitro by inhibiting bacterial urease activity. J Clin Pathol 51:220–224 [View Article][PubMed]
PeterfreundG. L., VandivierL. E., SinhaR., MarozsanA. J., OlsonW. C., ZhuJ., BushmanF. D.2012; Succession in the gut microbiome following antibiotic and antibody therapies for Clostridium difficile. PLoS ONE 7:e46966 [View Article][PubMed]
RotramelA., PoritzL. S., MessarisE., BergA., StewartD. B.2012; PPI therapy and albumin are better predictors of recurrent Clostridium difficile colitis than choice of antibiotics. J Gastrointest Surg 16:2267–2273 [View Article][PubMed]
WalkS. T., MicicD., JainR., LoE. S., TrivediI., LiuE. W., AlmassalhaL. M., EwingS. A., RingC.other authors2012; Clostridium difficile ribotype does not predict severe infection. Clin Infect Dis 55:1661–1668 [View Article][PubMed]