Levofloxacin-resistant haemophilus influenzae, Taiwan, 2004-2010

Abstract

Levofloxacin resistance in Haemophilus influenzae has increased significantly in Taiwan, from 2.0% in 2004 to 24.3% in 2010 (p<0.001). Clinical and molecular investigations of 182 levofloxacin-resistant isolates revealed that the increase was mainly the result of the spread of several clones in the elderly population in different regions.

Keywords: GyrA; Haemophilus influenzae; ParC; Taiwan; antimicrobial resistance; bacteria; fluoroquinolone resistance; levofloxacin; respiratory infections.

Figure

Dendrogram showing pulsed-field gel electrophoresis (PFGE) results for levofloxacin-resistant Haemophilus influenzae isolates digested by SmaI. Salmonella enterica serovar Braenderup strain H9812 (ATCC BAA664) was used as standard for DNA pattern normalization. PFGE patterns were analyzed by using BioNumerics software (Applied Maths NV, Sint-Martens-Latem, Belgium). For mutation profiles of the quinolone-resistance determining regions (QRDR) in GyrA and ParC, see Table 3. *Isolates having >80% similarity or <6 band differences were assigned a PFGE cluster if there were >3 isolates within the cluster; †region of hospital location: C, central; N, north; S, south. –, no isolates found. (n), number of isolates having the same PFGE pattern; MLST, multilocus sequence typing; (N), number of isolates on which MLST was performed; SLV, single locus variant, DLV, double locus variant.