Although there are many potential sources for Klebsiella sp. bacteremia, C. difficile infection (CDI) itself may be associated with GI translocation of enteric organisms.
A retrospective study of over 1300 patients found an incidence of 1.8% for CDI-associated bacteremia. E. coli, Klebsiella sp. , or Enterococcus sp. accounted for 72% of cases. History of malignancy, neutropenia (at the time of CDAD), and younger age (mean 59 y) were among the risk factors.1 Another study reported over 20 cases of bacteremia caused by C. difficile plus other bacteria often of enteric origin such the aforementioned organisms, Bacteroides sp, Candida sp, and Enterobacter sp.2
CDI is thought to predispose to bacterial translocation through the GI tract by alteration of mucosal indigenous microflora, overgrowth of certain pathogens, and presence of inflammation in the mucosa.3 Interestingly, C. difficile toxin A or B may play an active role in the bacterial adherence and penetration of the intestinal epithelial barrier.4
Bonus pearl: Did you know that C. difficile may be found in the normal intestinal flora of 3% of healthy adults, 15-30% of hospitalized patients, and up to 50% of neonates? Why neonates seem immune to CDI is another fascinating story!
- Censullo A, Grein J, Madhusudhan M, et al. Bacteremia associated with Clostridium difficile colitis: incidence, risk factors, and outcomes. Open Forum Infectious Diseases, Volume 2, Issue suppl_1, 1 December 2015, 943, https://doi.org/10.1093/ofid/ofv133.659 https://academic.oup.com/ofid/article/2/suppl_1/943/2635179
- Kazanji N, Gjeorgjievski M, Yadav S, et al. Monomicrobial vs polymicrobial Clostridum difficile bacteremia: A case report and review of the literature. Am J Med 2015;128:e19-e26. https://www.amjmed.com/article/S0002-9343(15)00458-1/abstract
- Naaber P, Mikelsaar RH, Salminen S, et al. Bacterial translocation, intestinal microflora and morphological changes of intestinal mucosa in experimental models of Clostridium difficile infection. J Med Microbiol 1998; 47: 591-8. https://www.ncbi.nlm.nih.gov/pubmed/9839563
- Clostridium difficile toxins may augment bacterial penetration of intestinal epithelium. Arch Surg 1999;134: 1235-1242. https://jamanetwork.com/journals/jamasurgery/fullarticle/390434
Yes! Although a common cause of colitis, an increasing number of reports in the literature suggest C. difficile can cause enteritis as well.1 Antibiotic use is a major risk factor in most reports, with nearly one-half of the cases reported in patients with inflammatory bowel disease, many post-colectomy. 1-3
Mortality of C. difficile enteritis based on the first 83 cases in the literature appears to be 23%,1 but as high as 60%-83% depending on the report!2 Its diagnosis post-colectomy requires a high index of suspicion, as patients may not complain of “diarrhea” with chronically loose stools in the ileostomy bag. Be particularly on the lookout for C. difficile enteritis in these patients when there is increased stool output, fever, hypotension, and/or leukocytosis2, and when in doubt, send a stool specimen from the ileostomy bag for C. difficile testing.
Although the pathophysiology of C. difficile enteritis is not fully understood, few observations are particularly intriguing:
- Small bowel mucosa may be colonized by C. difficile in about 3% of the population, potentially serving as a reservoir.2
- Patients with ileostomy may develop a metaplasia of the terminal end mimicking colonic environment.4
- Exposure of rabbit ileum to C. difficile toxin A also causes significant epithelial necrosis with destruction of villi and neutrophil infiltration.5
- Dineen SP, Bailey SH, Pham TH, et al. Clostridium difficile enteritis: a report of two cases and systematic literature review. World J Gastrointest Surg 2013;5:37-42. https://www.wjgnet.com/1948-9366/full/v5/i3/37.htm
- Boland E, Thompson JS. Fulminant Clostridium difficile enteritis after proctocolectomy and ileal pouch-anal anastomosis. Gastroenterology Research and Practice 2008; 2008: Article ID 985658. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2633454/pdf/GRP2008-985658.pdf
- Freiler JF, Durning SJ, Ender PT. Clostridium difficile small bowel enteritis occurring after total colectomy. Clin Infect Dis 2001;33:1429-31. https://pdfs.semanticscholar.org/333b/d84978cfc4ac8fd21a15bc8fd26ff3160387.pdf
- Apel R, Cohen Z, Andrews CW, et al. Prospective evaluation of early morphological changes in pelvic ileal pouches. Gastroenterology 1994;107:435-43. http://www.gastrojournal.org/article/0016-5085(94)90169-4/pdf
- Triadafilopoulos G, Pothoulakis C, Obrien MJ, et al. Differential effects of Clostridium difficile toxins A and B on rabbit ileum. Gastroenterology 1987;93:273-279. https://www.ncbi.nlm.nih.gov/pubmed/3596162
Proton pump inhibitors (PPIs) have been associated with increased risk of Clostridium difficile infection, as well as acute gastroenteritis (AG) caused by Salmonella, Campylobacter, and most recently, norovirus. 1,2
A recent prospective study1 of over 38,000 patients (mean age ~ 70 y) found a significant association between PPI use and AG leading to hospitalization with a dose-response relationship. PPI use increased the risk of Salmonella, Campylobacter, and C. difficile infections. Of note, H2 receptor antagonists were not associated with AG-related hospitalization in this study.
A 2017 retrospective case-control study also showed an association between PPI use and norovirus infection in hospitalized patients (mean age ~80 y in both groups). Most cases occurred during epidemic years with a median hospital stay of 5 days before onset of symptoms. Given the usually short incubation period of norovirus AG (typically 12-48 h), many of these cases likely acquired the infection during their hospital stay.
Besides reducing the acidity of gastric juice, PPIs may increase the risk of AG by causing an overgrowth of bacteria in the GI tract, reduce its motility and adversely affect the immune response, including neutrophil chemotaxis. 3
Does your patient really need a PPI?
- Chen Y, Liu B, Glass K, et al. Use of proton pump inhibitor and the risk of hospitalization for infectious gastroenteritis. PLoS One 2016;11:e0168618. Doi:10.1371/journal.pone. 0168618. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0168618
- Prag C, Prag M, Fredlund H. Proton pump inhibitors as a risk factor for norovirus infection. Epidemiol Infect 2017;145:1617-23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5426289/pdf/S0950268817000528a.pdf
- Wandall JH. Effects of omeprazole on neutrophil chemotaxis, super oxide production, degranulation, and translocation of cytochrome b-245. Gut 1992;33:617-21. https://www.ncbi.nlm.nih.gov/pubmed/1319381
Although proton pump inhibitors (PPIs) have received much attention for their link with CDI, H2RAs have also been associated with CDI. In a study of CDI among hospitalized patients, H2RA was associated with CDI (O.R. 1.53, 95% CI, 1.12-2.10); for daily PPI use the O.R. was 1.74 (95% CI, 1.39-2.18)1.
A meta-analysis in 2013 reported an overall O.R. of 1.44 (95% CI 1.22-1.7) for CDI in patients treated with H2RAs2. The estimated number needed to harm with H2RAs at 14 days after hospital admission was 58 for patients on antibiotics vs 425 for those not receiving antibiotics2.
Potential mechanism for H2RA-associated CDI is unclear, but survival of acid-sensitive vegetative forms of C. difficile in the stomach and their enhanced growth in the presence of bile salts related to gastro-esophageal reflux disease have been postulated2.
In brief, gastric acid suppression with H2RAs may increase the risk of CDI in hospitalized patients.
- Howell MD Novack V, Grgurich P, et al. Iatrogenic gastric acid suppression and the risk of nosocomial Clostridium difficile infection. Arch Intern Med 2010; 170:784-790.
- Tleyjeh IM, Bin Abdulhak AA, Riaz M, et al. The association between histamine 2 receptor antagonist use and Clostridium difficile infection: a systematic review and meta-analysis. PLoS ONE 2013; 8:e56498.
Most studies report such an association but its strength has varied among studies.
Many earlier reviews and meta-analyses had significant limitations, including use of unadjusted data from observational studies, and not assessing heterogeneity (variation in study outcomes) and the effect of publication bias1. A more recent meta-analysis of over 40 citations found an association between PPI use and CDI (O.R. 1.51, 95% CI, 1.26–1.83) adjusting for publication bias, but the association was weakened by the presence of significant heterogeneity in the published studies1. For the general population, the strength of the association was relatively weak (number needed to harm [NNTH] 3925 at 1 year), while for hospitalized patients it was much stronger (NNTH 50 at 2 weeks).
It is unclear how PPIs might increase risk of CDI as C. difficile spores are not killed by gastric acid2. They may interfere with the killing of the vegetative form of C. difficile by inhibiting gastric acid secretion or may delay gastric emptying with associated high intragastric bile salts which may trigger spore germination in the stomach; neither hypothesis has been proven, however2. Although a causal relationship has not been proven, judicious use of PPIs in high risk patients for CDI is advised.
- Tleyjeh IM, Bin Abdulhak AA, Riaz M, et al. (2012) Association between proton pump inhibitor therapy and Clostridium difficile infection: A contemporary systematic review and meta-analysis. PLoS ONE 2012; 7: e50836.
- Nerandzic MM, Pultz MJ, Donskey CJ. Examination of potential mechanisms to explain the association between proton pump Inhibitors and Clostridium difficile infection. Antimicrob Agents Chemother 2009;53(10): 4133–4137.
Although OVP is often administered to patients with history of CDI who require SAT, evidence to support this practice has been lacking until recently.
In a 2016 retrospective study of 203 patients with prior history of CDI, those who received OVP (125 mg or 250 mg 2x/daily) during the course of their SAT and for up to 1 week thereafter were significantly less likely to have a recurrence than the non-OVP group (4.2% vs 26.6%, respectively, O.R. 0.12 [C.I. 0.04-0.4]) (1). In this study, the mean interval between prior CDI and initiation of prophylaxis was 6.1 months (1-21 months), and the mean duration of prophylaxis following discontinuation of SAT was 1 day (0-6 days). Similar results have been reported by others (2,3).
Despite their retrospective nature, these studies lend support to the use of OVP in reducing the risk of recurrent CDI in patients who require SAT. It is unclear how long OVP should be continued after SAT is completed, if at all, but common practice is 1-2 weeks.
A randomized-controlled study comparing OVP 125 mg daily for the duration of SAT plus 5 days vs placebo appears to be on the way (4)!
- Van Hise NW, Bryant AM, Hennessey EK, Crannage AJ, Khoury JA, Manian FA. Efficacy of oral vancomycin in preventing recurrent Clostridium difficile infection in patients treated with systemic antimicrobial agents. Clin Infect Dis 2016; Advance Access published June 17, 2016. Doi.10.1093/cid/ciw401.
- Carignan A, Sebastien Poulin, Martin P, et al. Efficacy of secondary prophylaxis with vancomycin for preventing recurrent Clostridium difficile infections. Am J Gastroenterol 2016;111: 1834-40. https://www.ncbi.nlm.nih.gov/pubmed/27619835
- Granetsky A, Han JH, Hughes ME, et al. Oral vancomycin is highly effective in preventing Clostridium difficile infection in allogeneic hematopoietic stem cell transplant recipients. Blood 2016;128:2225; http://www.bloodjournal.org/content/128/22/2225?sso-checked=true
Disclosure: The author of this post was also a co-investigator of one of the studies cited (ref. 1).
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To date only 1 study has attempted to evaluate metronidazole’s role in preventing CDI1. This work, however, has significant shortcomings including its retrospective nature, definition of metronidazole prophylaxis as any dose for reasons other than CDI starting 1-3 days before initiation of the primary antibiotic, undefined duration, less comorbidities in the metronidazole group, and surveillance period for CDI limited to only 7 days following initiation of the primary antibiotic. For these reasons, it is difficult to interpret the results of this study whose conclusion was that metronidazole may protective against CDI2.
In fact, there are several reasons why metronidazole prophylaxis may not be effective in CDI. First, due to its very high bioavailability, concentrations of metronidazole in formed stool are often undetectable2,3 . Consequently, “preventive” metronidazole in patients at risk of CDI but with formed stools would not be expected to achieve high enough concentrations in the colon to be effective. In additions, metronidazole itself may be associated with CDI4 and vancomycin-resistant enterococci5, and has several potential drug-interactions and adverse effects6 .
- Rodriguez S, Hernandez MB, Tarchini G, et al. Risk of Clostridium difficile infection in hospitalized patients receiving metronidazole for a non-C difficile infection. Clin Gastroenterol Hepatol 2014;12:1856-61. https://www.ncbi.nlm.nih.gov/pubmed/24681079
- Dupont HL. Chemoprophylaxis of Clostridium difficile infections in high-risk hospitalized patients. Clin Gastroenterol Hepatol 2014;12: 1862-63. https://www.ncbi.nlm.nih.gov/labs/articles/24768812/
- Bolton RP, Culshaw MA. Faecal metronidazole concentrations during oral and intravenous therapy for antibiotic associated colitis due to Clostridium difficile. Gut 1986;27:1169-1172. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1433873/pdf/gut00370-0065.pdf
- Daly JJ, Chowdary KV. Pseudomembranous colitis secondary to metronidazole. Dig Dis Sci 1983;28:573-4.
- Carmeli Y, Eliopoulos GM, Samore MH. Antecedent treatment with different antibiotic agents as a risk factor for vancomycin-resistant enterococcus. Emerg Infect Dis 2002;8:802-807. https://wwwnc.cdc.gov/eid/article/8/8/pdfs/01-0418.pdf
- Salvatore M, Meyers BR. Metronidazole. In Mandel, Douglas, Bennett’s Principles and Practice of Infectious Diseases-7th Ed. p. 419-426. 2010, Churchill Livingstone, Philadelphia.