title: Bordetella pertussis isolates with a heterogeneous phenotype for erythromycin resistance.
abstract: Erythromycin is currently being used for both prophylaxis and treatment of pertussis infections. Erythromycin resistance was first recognized in Bordetella pertussis in Arizona in 1994, and since then, three additional resistant isolates have been identified in the United States. To better assess the potential public health impact of erythromycin-resistant B. pertussis, we used the disk diffusion assay to evaluate the frequency of erythromycin resistance among 1,030 recently circulating U.S. isolates and found the rate of occurrence to be <1%. We also describe a novel heterogeneous phenotype, with erythromycin-resistant colonies appearing only after a 7-day incubation period. To optimize patient management, we recommend that clinicians be alert to potential treatment failures and that laboratorians use a 7-day incubation period when screening for resistance. Our ongoing national surveillance will continue to monitor for resistant B. pertussis isolates and their potential association with changing pertussis epidemiology.
authors.affiliation: Meningitis and Special Pathogens Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
authors.forename: K E
authors.initials: KE
authors.lastname: Wilson
authors.forename: P K
authors.initials: PK
authors.lastname: Cassiday
authors.forename: T
authors.initials: T
authors.lastname: Popovic
authors.forename: G N
authors.initials: GN
authors.lastname: Sanden
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001886:Bordetella pertussis / Q000145:classification* / Q000187:drug effects* / Q000302:isolation & purification; D024881:Drug Resistance, Bacterial; D004917:Erythromycin / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D010641:Phenotype; D011159:Population Surveillance; D014917:Whooping Cough / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D004917:Erythromycin