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appendix 2 Spectrum of Activity 283
Table A–1
Suceptibility of E. coli to Ciprofloxacin at Three
Hospitals
Antimicrobial Organism Year Site % Susceptible
Ciprofloxacin E. coli 1998 Major Medical Center:
Adults
Ciprofloxacin E. coli 2008 Major Medical Center:
Adults
96.3
58.0
Ciprofloxacin E. coli 2008 Trauma Hospital 85.0
Ciprofloxacin E. coli 2008 Regional Children’s
Hospital
94.0
One key aspect of variability is time: you can
see that in 1998, ciprofloxacin had excellent activity
against E. coli isolated from inpatients at Major
Medical Center. Over the next decade, its activity
declined sharply. So it is important to keep “when”
in perspective when reading the literature about
spectrum of activity; sadly, the general trend is
for susceptibility to decrease over time. Another
aspect of variability is “where.” Trauma Hospital is
just on the other side of town from Major Medical
Center, but among patients there, ciprofloxacin is
much more active. There can be substantial geographic
variability in susceptibility in different
countries, states, regions, and even, as illustrated
here, within a city. Although the variability in this
case is most related to the last consideration, “who,”
as illustrated by the excellent activity of ciprofloxacin
against E. coli among patients at the Regional
Children’s Hospital. Regional Children’s Hospital
is located within the Major Medical Center, so it is
not a matter of geography per se. Those patients
are less likely to be exposed to fluoroquinolones