PFPC Daily - April 9, 2005

Canadian readers might remember the news story a few weeks back about
a strain of the bacteria Clostridium Difficile being discovered at a
Toronto Hospital. The strain has killed over 100 people so far in
Quebec alone.

SEE: Toronto hospital reports C. difficile strain
http://tinyurl.com/5xwn3

New research suggests that fluoroquinolones might be a cause of
C.difficile outbreaks...

Muto CA, Pokrywka M, Shutt K, Mendelsohn AB, Nouri K, Posey K,
Roberts T, Croyle K, Krystofiak S, Patel-Brown S, Pasculle AW,
Paterson DL, Saul M, Harrison LH - "A large outbreak of Clostridium
difficile-associated disease with an unexpected proportion of deaths
and colectomies at a teaching hospital following increased
fluoroquinolone use" Infect Control Hosp Epidemiol 26(3):273-80 (2005)

BACKGROUND AND OBJECTIVE: Fluoroquinolones have not been frequently
implicated as a cause of Clostridium difficile outbreaks. Nosocomial
C. difficile infections increased from 2.7 to 6.8 cases per 1000
discharges (P < .001). During the first 2 years of the outbreak,
there were 253 nosocomial C. difficile infections; of these, 26
resulted in colectomy and 18 resulted in death. We conducted an
investigation of a large C. difficile outbreak in our hospital to
identify risk factors and characterize the outbreak.

METHODS: A retrospective case-control study of case-patients with C.
difficile infection from January 2000 through April 2001 and
control-patients matched by date of hospital admission, type of
medical service, and length of stay; an analysis of inpatient
antibiotic use; and antibiotic susceptibility testing and molecular
subtyping of isolates were performed.

RESULTS: On logistic regression analysis, clindamycin (odds ratio
[OR], 4.8; 95% confidence interval [CI95], 1.9-12.0), ceftriaxone
(OR, 5.4; CI95, 1.8-15.8), and levofloxacin (OR, 2.0; CI95, 1.2-3.3)
were independently associated with infection. The etiologic fractions
for these three agents were 10.0%, 6.7%, and 30.8%, respectively.
Fluoroquinolone use increased before the onset of the outbreak (P <
.001); 59% of case-patients and 41% of control-patients had received
this antibiotic class. The outbreak was polyclonal, although 52% of
isolates belonged to two highly related molecular subtypes.

CONCLUSIONS: Exposure to levofloxacin was an independent risk factor
for C. difficile-associated diarrhea and appeared to contribute
substantially to the outbreak. Restricted use of levofloxacin and the
other implicated antibiotics may be required to control the outbreak.