1. Community-onset Clostridium difficile Infection a a b
Dr Gracia Fellmeth , Dr Sucharita Yarlagadda , Dr Shabnam Iyer
a b
Specialty Registrar Public Health (Oxford Deanery); Consultant Microbiologist (Royal Berkshire Hospital)
Background Aims
Clostridium difficile infection (CDI) has traditionally been consid- The aims of our study were to estimate the
ered a nosocomial infection, with established risk factors including: prevalence of community-onset CDI (CO-
CDI) from diarrheal samples submitted
 age over 65 years from a community setting, and to identify
 recent in-patient hospital or long-term care facility stay risk factors for CDI in individuals previ-
 recent use of antimicrobials ously considered to be at low risk.
 concomitant use of multiple antibiotics
 immunosuppression Methods
 previous CDI
 underlying medical (especially gastro-intestinal) conditions. A standard questionnaire was used to retrospectively obtain infor-
mation on the CDI risk factors of 58 cases of CO-CDI diagnosed
Recently CDI has been increasingly observed in the community between 1st April 2008 and 31st March 2009 in a community in the
setting and in individuals without established risk factors. Although South of England. Each case was reviewed for the presence of es-
reasons for this changing epidemiology are not fully understood, tablished risk factors for CDI, i.e., age ≥ 65 years, in-patient hospi-
increasing host susceptibility due to novel risk factors, higher com- tal stay, and recent (within ≤ 4 weeks) receipt of broad spectrum
munity total antibiotic consumption, emergence of new epidemic C. antibiotics, and other, ‘non-established’ risk factors for CDI, such
difficile strains, and a growing reservoir of asymptomatic carriers as exposure to antibiotics more than 4 weeks preceding symptom
or colonised patients and animal reservoirs in the community are onset, out-patient and day-surgery hospital exposure, contact with a
possible explanations. hospitalised patient, and travel outside of the UK.
Results
Fifty-eight cases of CO-CDI were diagnosed among a total community population of
418,000, representing an estimated prevalence of CO-CDI of 1.29 per 10,000. All 58 cases
were successfully contacted, representing a 100% response rate. Four cases were excluded
from further analysis due to co-infection with Salmonella spp. and Campylobacter spp.
Cases were more likely to be female, aged between 31 and 40 years, and present in the spring
season (March to May), 2009 (Table 1). 46.3% (25/54) of cases had established risk factors
for CDI, 20.4% (11/54) had non-established risk factors, 16.7% (9/54) had no risk factors and
in the remaining 16.7% (9/54), available information was insufficient to classify by risk fac-
tor category (Table 2 and Figure 1).
Table 1: Summary of Case Characteristics
30
25
25
Number of Cases
20
15
11
9 9
10
5
0
Established Non-Established None Unknown
Risk Factors
Figure 1: Presence of Risk Factors among Cases of CO-CDI Table 2: Presence of Risk Factors among Cases of CO-CDI
Conclusions
Our study highlights some interesting issues. Recent receipt of antibiotics was the single most important risk factor for CO-CDI. How-
ever, overall less than half (46.3%) of all cases of CO-CDI were associated with established risk factors. Out-patient hospital exposure,
day-case surgical procedures, contact with recently hospitalised individuals, contact with known cases of CDI, and travel outside of the
UK were identified as non-established factors associated with developing CO-CDI. This suggests that CDI should be considered as a dif-
ferential diagnosis even in the absence of established risk factors. Larger and more systematic studies are needed to investigate these pos-
sible associations further, and to assess whether routine testing for CDI significantly affects case management.
Our study had a number of important limitations. Cases presenting to general practitioners represent only the minority of all cases in a
population, and reported cases might differ systematically (e.g. in severity) from unreported cases. The small total number of cases led to
greater uncertainty around estimate, and the significant (16.7%) proportion of questionnaires excluded due to insufficiency of information
added further uncertainty. The retrospective nature of the study raises the possibility of recall bias.
Dr Gracia Fellmeth, Department of Public Health, Oxford University, Old Road Campus, Oxford OX3 8EQ. E-mail: gracia.fellmeth@nhs.net.