ページの先頭です
HOME > Past Issue List > Issue List > Abstract
言語を選択(Language)
日本語(Japanese)English

Abstract

Vol.54 No.2 March 2006

Drug resistance caused by qualitative changes in respiratory pathogen components

Kimiko Ubukata

Kitasato Institute for Life Sciences and Graduate School of Infection Control Sciences, Kitasato University,
5-9-1Shirokane, Minato-ku, Tokyo108-8641, Japan

Abstract

Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus pyogens, and Mycoplasma pneumoniae are causative pathogens widely detected in community-aquired respiratory tract infections (RTIs). In Japan, the rapidly increasing prevalence of isolates resistant to multiple antibiotics is becoming a serious clinical problem. Resistance to β-lactam agents in S. pneumoniae and H. influenzae has occurred due to changes in penicillin-binding proteins (PBPs) encoded by pbp genes. Macrolide resistance in S. pneumoniae and S. pyogenes are mediated by 2 mechanisms-efflux pumping by the mefA gene and methylation of the ribosomal protein by ermB or ermA (ermTR) genes. Macrolide resistance in M. pneumoniae is also mediated by a mutation detected in domain V of the 23 S rRNA gene.
In Japan, although the frequency of S. pneumoniae resistant to new quinolones is 1-2%, we confirmed that the mechanism of resistance occurred due to mutations on the gyrA gene encoding DNA gyrase and those on the parC and parE genes encoding topoisomerase IV.
Resistance caused by qualitative changes in pathogen components is characterized as intermediate resistance not clearly distinguished by conventional susceptibility testing. The resistant level is also the approximate concentration aquired by oral antibiotics dosing of β-lactams, macrolides, and new quinolone agents. Microorganisms bearing mutations in genes encoding resistance-associated enzymes are easily selected by insufficient concentrations of oral antibioitics.
Several actions prevent such resistance from increasing: rapid identification of causative pathogens, vaccination against these pathogens, proper selection and use of antibiotics based on PK/PD, and the establishment of postmarketing surveillance of antibiotics.

Key word

drug resistance, qualitative alteration, Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae

Received

January 23, 2006

Accepted

January 26, 2006

Jpn. J. Chemother. 54 (2): 69-94, 2006