title: Emergence of a multidrug-resistant Haemophilus influenzae strain causing chronic pneumonia in a patient with common variable immunodeficiency.
abstract: We report the emergence of a multidrug-resistant Haemophilus influenzae strain in a patient with common variable immunodeficiency suffering from recurrent bronchopneumonia caused by H. influenzae. After the patient had received several antibiotic therapies, a strain was isolated showing resistance to ampicillin, ampicillin/sulbactam, cefazolin, cefuroxime, ciprofloxacin, and clarithromycin. Polymerase chain reaction analyses and sequencing revealed the presence of the beta-lactamase gene bla(TEM-1), two mutations (A502T and R517H) in the ftsI gene encoding the transpeptidase region of the penicillin-binding protein 3, and one mutation in the ribosomal protein gene L4 (G65D) conferring resistance to beta-lactams and macrolides, respectively. Additionally, the plasmid-encoded aac(6')-Ib-cr gene mediating slightly reduced susceptibility to quinolones and two mutations in the DNA gyrase gene gyrA and one mutation in the topoisomerase IV gene parC were identified leading to a high-level fluoroquinolone-resistant phenotype. In conclusion, the treatment of H. influenzae infections accompanied by high bacterial loads such as bronchopneumonia can be complicated by the selection of multidrug-resistant strains. Moreover, the emergence of aac(6')-Ib-cr in H. influenzae causing low fluoroquinolone resistance levels might have contributed to the selection of DNA gyrase and topoisomerase IV mutants.
authors.affiliation: Robert-Koch-Institute, FG13 Nosocomial Infections, Wernigerode, Germany.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Pfeifer
authors.forename: Ines
authors.initials: I
authors.lastname: Meisinger
authors.forename: Klaus
authors.initials: K
authors.lastname: Brechtel
authors.forename: Sabine
authors.initials: S
authors.lastname: Gröbner
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D017074:Common Variable Immunodeficiency / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006192:Haemophilus Infections / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D006193:Haemophilus influenzae / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D009154:Mutation; D018410:Pneumonia, Bacterial / Q000188:drug therapy / Q000276:immunology / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents