This article is more than 5 years old. Information may no longer be current.
C. difficile ribotype 027 no more virulent than other strains
Clostridium difficile ribotype 027, thought to be linked to the most severe outcomes, was shown to be comparably virulent to other strains in a recent study, confirming the importance of clinical severity markers for predicting outcomes.
“Clinical severity markers of [C. difficile infection], such as white blood cell count and albumin level … are more important predictors of severe outcomes than any specific strain, especially in hospitals with no single predominant strain,” Samuel L. Aitken, PharmD, from the University of Houston College of Pharmacy and Houston Methodist Hospital, said in a press release.
Samuel L. Aitken
To evaluate severity of disease presentation and outcomes of patients infected with different C. difficile ribotypes in an endemic setting, and to determine the utility of disease severity at presentation vs. ribotype in predicting outcomes, Aitken and colleagues performed a multicenter cohort study involving seven hospitals in Houston from 2011 to 2013.
They collected and cultured C. difficile-positive stool samples from 715 patients aged 61 ± 18 years (63% women; 45% hospital-onset infection; median Charlson comorbidity index score, 2.5 ± 2.4) and characterized strains using a fluorescent polymerase-chain reaction ribotyping method. They also collected clinical characteristics from medical records and evaluated associations between ribotypes and severe presentation/outcomes.
The most common ribotypes were 027 (24%), 014-020 (17%), FP311 (10%), 002 (10%), 078-126 (6%), 001 (5%) and FP324 (5%). Severe C. difficile infection was present in 35.9% of patients and severe outcomes occurred in 12.3%.
Multivariate analysis showed ribotype 027 was an independent predictor of severe disease (adjusted OR = 2.24; 95% CI, 1.53-3.29) and severe outcomes (aOR = 1.71; 95% CI, 1.02-2.85) compared with other ribotypes. A second multivariate model using all common ribotypes as individual variables showed ribotype 027 was not more frequently associated with severe outcomes, while ribotype 014-020 was associated with a lower incidence of severe outcomes (aOR = 0.26; 95% CI, 0.1-0.68). A third multivariate model showed severe disease presentation was associated with severe outcomes (aOR = 4.19; 95% CI, 2.46-8.07).
“In conclusion, C. difficile ribotype 027 showed virulence equal to that of other ribotypes identified in this endemic setting,” the researchers wrote. “These results were largely due to … certain ribotypes (eg, R014-020) with decreased [C. difficile infection] disease severity and outcomes, suggesting that the comparator strains in the population being studied helps determine apparent virulence.”
“Strain typing remains a valuable source of information for tracking emergence of different strains and may potentially influence treatment decisions,” Aitken said in the release, “but clinical severity markers appear to be more important predictors for … determining the severity of [C. difficile infection] patient outcomes.” – by Adam Leitenberger
Disclosure: Aitken reports no relevant financial disclosures. Please see the study for a full list of all other researchers’ relevant financial disclosures.