This article is more than 5 years old. Information may no longer be current.
High incidence of C. difficile may be associated with large clusters of specific types
The molecular epidemiology of Clostridium difficile incidence rates may be characterized by a wide diversity of rotating dominant types over time, according to results of a recent study.
Researchers conducted HindIII restriction endonuclease analysis typing on available C. difficile isolates at the Minneapolis VA Medical Center from 1982 to 1991.
Annual incidence rates ranged from 3.2 to 9.9 cases per 1,000 discharges. High incidence years were 1982, 1983, 1985 and 1991 (mean ± standard deviation number of cases for the high- vs. low-incidence years, 121.8 ± 20.4 and 70.0 ± 15.0; P=.002).
There were 696 isolates available for restriction endonuclease analysis typing during the study period.
During the high incidence years, large clusters, which the researchers defined as >10 C. difficile cases in consecutive months, were caused by types B1 and B2 in 1982 and 1983, F2 and B1 in 1985, and K1 in 1991.
Small clusters were defined as four to nine cases in consecutive months. Small clusters were caused by types G1 in 1984, Y4 and Y6 in 1987, Y2 in 1988, L1 in 1989, Y1 in 1990 and K1 in 1991.
The type that is causing the current epidemic, BI (which is unrelated to type B1), was isolated six times in the study period: twice per year in 1984, 1988 and 1990.
Belmares J et al. Clin Infect Dis. 2009;49:1141:1147.