In vitro investigation of the indirect pathogenicity of beta-lactamase-producing microorganisms in the nasopharyngeal microflora

Satoru Kaieda, Hisakazu Yano, Naohiro Okitsu, Yoshio Hosaka, Ryoichi Okamoto, Matsuhisa Inoue, Haruo Takahashi

    研究成果: Article査読

    9 被引用数 (Scopus)

    抄録

    Objective: Nasopharyngeal microflora contains some beta-lactamase-producing microorganisms. In this study, we investigated in vitro on the indirect pathogenicities of Haemophilus parainfluenzae (H. parainfluenzae) and Moraxella catarrhalis (M. catarrhalis) against the antipneumococcul activities of some beta-lactams. Methods: We compared the antimicrobial and bactericidal activities of beta-lactams against penicillin-susceptible Streptococcus pneumoniae (PSSP) with or without presence of the enzymes of two species of beta-lactamase- producing microorganisms, H. parainfluenzae and M. catarrhalis. Results: When adding the enzymes extracted from these two beta-lactamase-producing microorganisms in equivalent amounts of 107 CFU/spot, the minimum inhibitory concentrations of amoxicillin (AMPC) and cefaclor (CCL) increased to >64 μg/mL. Even third-generation cephalosporins, such as cefditren (CDTR) and ceftriaxone (CTRX) showed marked increases with the enzyme of M. catarrhalis. In time-kill kinetics, same phenomenon was observed in mixed culture indicating the indirect pathogenicities of distinct bacteria, not extracted enzymes, on the cidal activities of beta-lactams against PSSP. Clavulanic acid (CVA)/AMPC, faropenem (FRPM), and imipenem (IPM) were not affected by these beta-lactamase-producing strains with respect to their activities against PSSP. However, these two beta-lactamase-producing strains and their enzymes did not show any significant influence on the antipneumococcul activities of beta-lactams, until the number of bacterial cells reached >108 CFU/mL. Conclusion: Our results suggest that these two species of beta-lactamase-producing microorganisms in the nasopharyngeal microflora may act as indirect pathogens on the antipneumococcul activities of beta-lactams with reflecting their substrate profiles, but this is dependent on sufficient amounts of enzyme for their influence as indirect pathogens.

    本文言語English
    ページ(範囲)479-485
    ページ数7
    ジャーナルInternational Journal of Pediatric Otorhinolaryngology
    69
    4
    DOI
    出版ステータスPublished - 2005 4

    ASJC Scopus subject areas

    • 小児科学、周産期医学および子どもの健康
    • 耳鼻咽喉科学

    フィンガープリント

    「In vitro investigation of the indirect pathogenicity of beta-lactamase-producing microorganisms in the nasopharyngeal microflora」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

    引用スタイル