You are here: Home Published Research Molecular epidemiology of nontypeable Haemophilus influenzae causing community-acquired pneumonia in adults.

Carmen Puig, Laura Calatayud, Sara Martí, Fe Tubau, Carolina Garcia-Vidal, Jordi Carratalà, Josefina Liñares, and Carmen Ardanuy (2013)

Molecular epidemiology of nontypeable Haemophilus influenzae causing community-acquired pneumonia in adults.

PloS one, 8(12):e82515.

Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen which causes a variety of respiratory infections. The objectives of the study were to determine its antimicrobial susceptibility, to characterize the β-lactam resistance, and to establish a genetic characterization of NTHi isolates. Ninety-five NTHi isolates were analyzed by pulsed field gel electrophoresis (PFGE) and multi locus sequence typing (MLST). Antimicrobial susceptibility was determined by microdilution, and the ftsI gene (encoding penicillin-binding protein 3, PBP3) was PCR amplified and sequenced. Thirty (31.6%) isolates were non-susceptible to ampicillin (MIC ≥ 2 mg/L), with 10 of them producing β-lactamase type TEM-1 as a resistance mechanism. After ftsI sequencing, 39 (41.1%) isolates showed amino acid substitutions in PBP3, with Asn526 → Lys being the most common (69.2%). Eighty-four patients were successfully treated with amoxicillin/clavulanic acid, ceftriaxone and levofloxacin. Eight patients died due either to aspiration or complication of their comorbidities. In conclusion, NTHi causing CAP in adults shows high genetic diversity and is associated with a high rate of reduced susceptibility to ampicillin due to alterations in PBP3. The analysis of treatment and outcomes demonstrated that NTHi strains with mutations in the ftsI gene could be successfully treated with ceftriaxone or fluoroquinolones.

Aged, Aged, 80 and over, Anti-Bacterial Agents, Community-Acquired Infections, Female, Genotype, Haemophilus Infections, Haemophilus influenzae, Humans, Male, Microbial Sensitivity Tests, Middle Aged, Molecular Epidemiology, Mutation, Penicillin-Binding Proteins, Phenotype, Phylogeny, Pneumonia, Bacterial, Retrospective Studies
Aged, Aged, 80 and over, Anti-Bacterial Agents, Community-Acquired Infections, Female, Genotype, Haemophilus Infections, Haemophilus influenzae, Humans, Male, Microbial Sensitivity Tests, Middle Aged, Molecular Epidemiology, Mutation, Penicillin-Binding Proteins, Phenotype, Phylogeny, Pneumonia, Bacterial, Retrospective Studies
 
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