By Emma Hitt, PhD
9-21-1
ATLANTA (Reuters Health) - For the first time in the US,
a bacterium important in causing pneumonia and other infections
appears to be developing resistance to a powerful class of
antibiotics called fluoroquinolones, according to the Centers
for Disease Control and Prevention (CDC).
The bacterium, called Streptococcus pneumoniae, is the leading
cause of the lung infection pneumonia, the infection of tissues
surrounding the brain called meningitis, and ear infection
in the US.
Bacteria can develop resistance to any antibiotic when physicians
prescribe that antibiotic too often, when it is not needed,
or when patients do not finish their prescribed course of
antibiotics.
In their study, the CDC researchers wanted to determine
how resistance of S. pneumoniae to fluoroquinolones increased
over time in the US.
From 1995 to 1999, they collected tissue samples from people
infected with S. pneumoniae living in seven states.
For the first 3 years, the investigators tested whether
the bacteria that infected each person could be killed with
a type of fluoroquinolone called ofloxacin.
According to the CDC report, the overall percentage of samples
infected with resistant bacteria was low--from about 2% to
4%. But ofloxacin resistance did increase each year from
1995 to 1997, indicating newly emerging resistance developing
in the bacteria.
From 1998 to 1999, the researchers then investigated bacterial
resistance to a newer type of fluoroquinolone called levofloxacin
and found that resistance also increased, although very slightly,
over the 2-year period.
Writing in the September 21st issue of the agency's Morbidity
and Mortality Weekly Report, the CDC authors note that fluoroquinolone
resistance was also linked to resistance to other types of
antibiotics such as penicillin.
Fluoroquinolones are being prescribed with increasing frequency
and this may increase resistance, the researchers suggest.
From 1993 to 1998, fluoroquinolone prescriptions nearly doubled
in the US and were highest among people aged 65 and older.
The CDC researchers stress that appropriate use of antibiotics
is necessary to slow the emergence of fluoroquinolone-resistant
pneumococci and they point out that few other types of antibiotics
are useful in treating this type of infection.
``Although fluoroquinolone resistance is still limited,
we have seen an increase that may be related to antibiotic
use, which is new in this country,'' the CDC's Dr. Montse
Soriano-Gabarro told Reuters Health. ``It is hard to say
whether resistance will increase,'' she said, but ``resistance
will likely increase as use increases.''
Soriano-Gabarro added, ``People need to be aware that antibiotics
should only be used when appropriate. They should also understand
that when a physician doesn't prescribe an antibiotic, (he
or she) may have good reason for not doing so.''
SOURCE: Morbidity and Mortality Weekly Report 2001;50: 800-804
