45th Interscience Conference on Antimicrobial Agents

In: Main

8 Apr 2010

Interscience ConferenceTelithromycin Preferred for Acute Maxillary Sinusitis

Speaker: Itzhak Brook, MD, MSc, Professor, Department of Pediatrics, Georgetown University School of Medicine, Washington, DC

The ketolide telithromycin (Ketek, Sanofi Aventis) has been found to be more effective than the macrolide azithromycin (Pfizer) in eradicating Streptococcus pneumoniae from the nasopharynges of patients with acute maxillary sinusitis. Furthermore, the emergence of antimicrobial resistance following therapy occurs only with azithromycin.

The growing resistance of S. pneumoniae to penicillin and macrolides has resulted in the development of a new class of antibiotics—the ketolides. A study designed to compare the efficacy of telithromycin with that of azithromycin enrolled 105 patients with acute maxillary sinusitis. Fifty-nine patients received once daily for three days, and 46 patients received telithromycin 800 mg once daily for five days. Nasopharyngeal cultures were obtained before therapy and at a follow-up visit 10 to 12 days after antibiotic therapy was initiated.

Prior to therapy, 67 potential pathogens had been recovered in 57 patients; 32 of these patients received telithromycin, and 25 received azithromycin. Overall, there were 31 isolates of S. pneumoniae: 14 in the azithromycin patients and 17 in the telithromycin patients.

There were also 13 Haemophilus influenzae non-type b pathogens, eight of Staphylococcus aureus, and seven of Moraxella catarrhalis. A single pathogen was recovered in 46 patients, two pathogens were found in six patients, and three different pathogens were found in three patients. No pathogens were found in 48 patients.

Of the 14 S. pneumoniae isolates found before therapy in the azithromycin patients, seven were resistant to penicillin, four were resistant to macrolides, and none were resistant to telithromycin.

Of the 17 S. pneumoniae isolates in the telithromycin group, nine were resistant to penicillin, six were resistant to macrolides, and none were resistant to telithromycin.

Following treatment, the number of S. pneumoniae isolates in the azithromycin patients was reduced from 14 to eight. Five of these isolates were resistant to azithromycin prior to therapy. By contrast, the number of S. pneumoniae isolates in the telithromycin patients was reduced from 17 to one after treatment. No differences were noted in the bacterial eradication rate of all other groups of isolates, all of which were susceptible to both azithromycin and telithromycin.

The development of resistance to the antimicrobial agents used was reported in only five isolates (four of S. pneumoniae and one of H. influenzae). These resistant isolates were recovered only from patients who had received azithromycin canadian.

Cefprozil Useful in Pediatric Acute Otitis Media

Speaker: Michael E. Pichichero, MD, Professor of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York
Cefprozil (Cefzil, Bristol-Myers Squibb), a second-genera­ tioncephalosporin, appears to be of particular value in children with persistent or recurrent otitis media.

A trial using double-tympanocenteses (taps) was conducted in 66 children, ranging in age from five months to four years, with 76% younger than 24 months of age. Of these children, 41% had recurrent acute otitis media and 29% had persistent acute otitis media from 2003 to 2004. The patients received oral cef-prozil 5 mg/kg twice daily for 10 days.

Cultures were initially positive in about two thirds of the patients. Initial taps resulted in the growth of beta-lacta-mase-producing (blac+) Haemophilus influenzae (Hi) in 23 children; drug-resistant Streptococcus pneumoniae (Spn) grew in 22 children, Hi and Spn grew in four children, Moraxella catarrhalis grew in three children, and other pathogens developed in two children. The number of organisms isolated from the children with positive cultures was more than 45 because of multiple organisms isolated in several patients.

Bacteriological eradication on the fourth to sixth days by repeated taps was achieved in 78% (39/50) of the children, with three newly emerging infections identified during the antibiotic treatment period. In this group, 13 of 15 penicillin-susceptible pneumococci were eradicated, five of seven penicillin-intermediate pneumococci were eradicated, and 16 of 23 Hi isolates were eradicated, including three of five blac+ Hi and 13 of 18 blac- Hi.

No taps were conducted in five patients who were presumed to have been cured, because no middle-ear fluid was present. Four of the other pathogen isolates were eradicated, and no tap was performed for one isolate.
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At four to seven days after the completion of treatment, the rates of clinical cure, including those children with super-infection during treatment, were as follows:

  • 91% (20/20 patients) against Hi
  • 79% (11/14 patients) against penicillin-susceptible pneumococci
  • 80% (3/6 patients) against penicillin-intermediate pneumococci
  • 75% (3/4 patients) against other pathogens

The overall clinical cure rate was 80% (37/46).

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