KETEK® (telithromycin) is highly active in vitro against Streptococcus pneumoniae (S. pneumoniae) isolates

May 24 2004

Results from an ongoing surveillance study, PROTEKT US (Prospective Resistant Organism Tracking and Epidemiology of the Ketolide Telithromycin – United States) Year 2 (2001-2002), suggest that KETEK® (telithromycin) is highly active in vitro against Streptococcus pneumoniae (S. pneumoniae) isolates, including those resistant to other antimicrobial agents. These data were presented today at the 100th International Conference of the American Thoracic Society (ATS).

Increasing multi-drug resistance among S. pneumoniae isolates compromises the treatment of community-acquired respiratory tract infections. This study found that nearly 30% (n=2,805) of S. pneumoniae isolates were resistant to several antibacterials, including penicillin, cefuroxime, erythromycin, clindamycin, levofloxacin, tetracycline and co-trimoxazole, while more than 99% (n=9,517) of S. pneumoniae isolates were susceptible to KETEK, irrespective of multi-drug resistance. A total of 242 centers submitted 9,531 S. pneumoniae isolates for the study.

“The increasing incidence of multi-drug resistant S. pneumoniae poses a challenge in the management of community-acquired respiratory tract infections,” said Steven Brown, PhD, of the Clinical Microbiology Institute, Wilsonville, Oregon and the lead author of the poster. “As results from PROTEKT US demonstrate, KETEK is active against these resistant strains of S. pneumoniae in vitro.”

Data from PROTEKT US were analyzed to determine the prevalence of multi-drug resistance (defined as resistant to ≥2 antimicrobials) among S. pneumoniae isolates.

A total of 9,531 S. pneumoniae isolates from bronchoalveolar lavage, blood, ear, nasopharyngeal swab/aspirate, sinus and sputum cultures were examined from patients in 242 centers across the United States. Isolates were studied for in vitro resistance to penicillin, cefuroxime, erythromycin, clindamycin, levofloxacin, tetracycline and co-trimoxazole. Study results found that 2,805 of the S. pneumoniae isolates were multi-drug resistant. Resistance to four antibacterials was the most common type of multi-drug resistance in all culture sources. The most common example of multi-drug resistance was resistance to penicillin, cefuroxime, erythromycin and co-trimoxazole, accounting for 74.6% of four antimicrobial resistance from bronchoalveolar lavage cultures, 85.9% from blood cultures, 73.4% from ear cultures, 76.0% from nasopharyngeal swab/aspirate cultures, 73.8% from sinus cultures and 69.1% from sputum cultures. Overall, 99.9% of the S. pneumoniae isolates were susceptible to KETEK, ranging from 99.4% (bronchoalveolar lavage cultures) to 99.9% (blood and sputum).

The pathogen S. pneumoniae, which accounts for more than 4 million deaths annually, is recognized as the most important pathogen of the respiratory tract in adults and is identified as the most common etiologic agent in community-acquired pneumonia (CAP) and acute bacterial sinusitis. Additionally, it is the pathogen most associated with morbidity and mortality and is identified in virtually all CAP studies, causing approximately two thirds of all cases of bacteremic pneumonia. Resistance to established antibiotics continues to grow, with penicillin and macrolide resistance rates for S. pneumoniae reported at 39% and 31%, respectively.

PROTEKT US is one of the largest surveillance studies in the United States, evaluating in its first year more than 17,000 pathogens in more than 206 sites across 44 states. The study was initiated in 2000 and was designed to monitor the spread of resistant phenotypes and genotypes of the major respiratory tract infection pathogens across the nation. It is an ongoing study that is a branch of a larger international study called PROTEKT, which altogether includes more than 500 centers in 35 countries worldwide.

KETEK was recently approved by the U.S. Food and Drug Administration to treat community-acquired respiratory tract infections in patients age 18 and older with acute bacterial exacerbation of chronic bronchitis; acute bacterial sinusitis; and mild to moderate community-acquired pneumonia, including those infections caused by multi-drug resistant Streptococcus pneumoniae (MDRSP). In clinical trials, the most commonly reported side effects were nausea, headache, dizziness, vomiting, and diarrhea.

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