title: Susceptibility of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis to 17 oral antimicrobial agents based on pharmacodynamic parameters: 1998-2001 U S Surveillance Study.
abstract: Pharmacokinetic/pharmacodynamic parameters were used to interpret susceptibility data for the oral agents tested in a clinically meaningful way. Among S pneumoniae isolates, >99% were susceptible to respiratory fluoroquinolones, 91.6% to amoxicillin, 92.1% to amoxicillin/clavulanic acid (95.2% at the extended-release formulation breakpoint), 90.6% to clindamycin, 80.4% to doxycycline, 71.0% to azithromycin, 72.3% to clarithromycin, 71.8% to cefprozil and cefdinir, 72.6% to cefuroxime axetil, 66.3% to cexime, 63.7% to trimethoprim/sulfamethoxazole, and 19.7% to cefaclor. Among H influenzae isolates, 28.6% were b-lactamase positive, but virtually all were susceptible to amoxicillin/clavulanic acid (98.3%, with 99.8% at the extended-release formulation breakpoint), cexime (100%), and uoroquinolones (99.8%), whereas 93.5% were susceptible to cefdinir, 82.8% to cefuroxime axetil, 78.1% to trimethoprim/sulfamethoxazole, 70.2% to amoxicillin, 25.1% to doxycycline, 23.2% to cefprozil, and 5% to cefaclor, azithromycin and clarithromycin. Most isolates of M catarrhalis were resistant to amoxicillin, cefaclor, cefprozil, and trimethoprim/sulfamethoxazole. Thus significant b-lactam and macrolide/azalide resistance in Streptococcus pneumoniae and b-lactamase production and trimethoprim/sulfamethoxazole resistance in untypeable Haemophilus influenzae are still present. The results of this study should therefore be applied to clinical practice based on the clinical presentation of the patient, the probability of the patient's having a bacterial rather than a viral infection, the natural history of the disease, the potential of pathogens to be susceptible to various oral antimicrobial agents, the potential for cross-resistance between agents with S pneumoniae, and the potential for pathogens to develop further resistance. Antibiotics should be used judiciously to maintain remaining activity and chosen carefully based on activity determined by pharmacokinetic/pharmacodynamic-based breakpoints to avoid these bacteria developing further resistance, particularly to fluoroquinolones.
authors.affiliation: Department of Pathology, Case Western Reserve University and University Hospitals of Cleveland, 11100 Euclid Avenue, Cleveland, OH 44106, USA. mrj6@cwru.edu
authors.forename: Michael R
authors.initials: MR
authors.lastname: Jacobs
authors.forename: Saralee
authors.initials: S
authors.lastname: Bajaksouzian
authors.forename: Anne
authors.initials: A
authors.lastname: Windau
authors.forename: Caryn E
authors.initials: CE
authors.lastname: Good
authors.forename: Gengrong
authors.initials: G
authors.lastname: Lin
authors.forename: Glenn A
authors.initials: GA
authors.lastname: Pankuch
authors.forename: Peter C
authors.initials: PC
authors.lastname: Appelbaum
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D005260:Female; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D001936:Moraxella catarrhalis / Q000187:drug effects* / Q000302:isolation & purification; D011159:Population Surveillance; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000302:isolation & purification; D014481:United States
chemical_list: D000900:Anti-Bacterial Agents