Surveillance Data & Reports
The AWARE Project established a process to track resistance trends for Streptococcus pneumoniae infections in California. It is the most common bacterial cause of
meningitis, otitis media, and community-acquired pneumonia, and is a major cause of sinusitis. There are multiple drug classes targeted for research,
including penicillin, macrolides, and fluoroquinolones. By tracking trends in resistance, we can all help keep antibiotics working for everyone.
Working with the California Department of Public Health (CDPH), we receive antibiotic resistance data for Streptococcus pneumoniae from two laboratory systems: Kaiser
Regional Laboratories (North and South), since 1995 and TRUST, a private pharmaceutical company
sponsored system of clinical microbiology laboratories, since 1998-99. The data originated from clinical cultures of patients with respiratory infections.
From these data we have been able to make the following conclusions:
- Penicillin drugs can no longer be considered the drugs of choice for treating Streptococcus pneumoniae (pneumococcal) infections. Penicillin Resistance increased in California
throughout the 1990’s, reaching a peak in 2000 and has subsequently been decreasing to the present. During this time resistance levels have been consistently lower than those of the U.S.
as a whole. If this trend continues it is possible that penicillin may be able to be used for these infections again.
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Some of this decrease is likely due to the effects on penicillin resistance of the childhood pneumococcal vaccine (Prevnar), while some may be due
to improvements in antibiotic prescribing. AWARE is in the process of examining the latter possibility.
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Macrolide drugs (erythromycin, azithromycin, clarithromycin) became the drugs of choice for many pneumococcal infections as penicillin resistance increased. Although the TRUST data show that macrolide resistance in Strep pneumoniae in California is less
than macrolide resistance in the U.S. as a whole, after an initial decrease in 2001-2002 there has been an increase in macrolide resistance to the point where these agents may be becoming
less effective.
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Fluoroquinolone antibiotics such as levofloxacin are the third line of antibiotic defense against S. pneumoniae; resistance to these agents remains low in California and elsewhere.
In summary, the news is mixed at this point. Resistance to penicillin is decreasing, but it is still too early to tell if this will continue, and how much is due to better antibiotic
use is uncertain. While the third line fluoroquinolones can still be used, the situation for the second line macrolides continues to worsen, making their use for pneumococcal infections questionable. We need
to use the success with penicillin to motivate us to continue to decrease unnecessary antibiotic use, such as not using them for colds and the flu.
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