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Chemotherapy. 2012;58(5):352-7. doi: 10.1159/000343973. Epub 2012 Nov 24.

Antimicrobial resistance genotype trend and its association with host clinical characteristics in respiratory isolates of Haemophilus influenzae.

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Department of Respiratory Medicine, Kanagawa Cardiovascular and Respiratory Center, Yokohama, Japan.



β-Lactam resistance genotype trends in clinical isolates of Haemophilus influenzae and their correlation with the clinical background were analyzed.


Five hundred and ten respiratory isolates of H. influenzae collected during the period 2002-2009 were classified by PCR into gBLNAS (genotype for β-lactamase-negative ampicillin-susceptible), gBLNAR (genotype for β-lactamase-negative ampicillin-resistant) and 3 other genotypes. The associations with host clinical data and antimicrobial susceptibility were analyzed in all 144 isolates between 2008 and 2009.


The 8-year trend analysis detected an increase in gBLNAR with a decrease in gBLNAS. The probability of being a causative pathogen did not differ between genotypes. Host clinical characteristics such as age and gender did not differ with gBLNAR or gBLNAS, but the underlying respiratory diseases did differ. gBLNAR was found at the highest rate in 83% of isolates from patients with nontuberculous mycobacteriosis. In contrast, gBLNAR accounted for as little as 33% of isolates from chronic obstructive pulmonary disease.


There were no differences in the pathogenicity of gBLNAR and gBLNAS. The underlying respiratory diseases may be related to the resistance genotype.

[Indexed for MEDLINE]

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