Streptococcus pneumoniae (SP) is the most common n isolated from hospitalized patients with community-acquired pneumonia (CAP). SP resistant to penicillin and macrolides are increasingly common, and the emerging specter of multiple drug resistance (MDR; 32 drug resistant to penicillin, cefuroxime, erythromycin, tetracycline, or trimethoprim-sulfamethoxazole as previously defined by the U.S. FDA) is cause for concern. We reviewed the current activity of ceftriaxone, a well-established agent in treating CAP from 2003/4isolates.
We analyzed susceptibility data (Jan 2003 to Feb 2004) from TSN, a database containing routine results from >300 microbiology labs in the US. Results for a total of 4947 S. pneumoniae (SP) collected from LRTIs tested against ceftriaxone (CTX), and comparator agents used to define MDR phenotypes were considered. Analysis considered outpatient (OP), inpatient (IP), or intensive care unit (ICU) status. NCCLS (2004) methodology and breakpoints were applied.
Resistance in SP from OP, IP, and ICU was respectively 17.8, 16.4 and 17.7% for penicillin (PEN), 32.9, 33.1 and 32.1%, for erythromycin (ERY), 27.0, 28.7, 29.9% for cefuroxime (CEF), 28.3, 26.2, 27.3% for trimethoprim-sulfamethoxazole (SXT), 18.3, 14.4, 20.5% for tetracycline (TET) and 1.0, 1.7% and 1.6% for CTX. The incidence of MDR was 24.5% (318/1300) among SP from OT and IP combined. Of the FDA defined drugs considered, CTX was the least involved in the MDR phenotype, active against 97.8% of isolates. Against MDR SP, for other drugs considered resistance was 33.3% to TET, 55.5% R to PEN, 76.1% R to cefuroxime (CEF), 79.9% R to ERY, and 84.6% to SXT.
Independent of patient-location, despite the high incidence of PEN and macrolide-resistance, greater than 98% of SP remain susceptible to CTX. Additionally CTX retains activity against greater than 97.0% of MDR SP compared to approx. 65% for ERY.
After many years of clinical use, CTX retains its clinical utility despite widespread emergence of resistance and MDR in clinical isolates of SP.
M.E. Jones, None.