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[Detection methods for drug-resistant bacteria in routine examination--BLNAR].
S Misawa1, A Nakamura, T Oguri
1Clinical Laboratory, Juntendo University Hospital.
Rinsho Byori. the Japanese Journal of Clinical Pathology
|May 11, 2000
Summary
Beta-lactamase-negative, ampicillin-resistant (BLNAR) Haemophilus influenzae strains exhibit altered penicillin-binding proteins. Accurate susceptibility testing is crucial for serious infections to guide treatment effectively.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Haemophilus influenzae is a significant human pathogen.
- Beta-lactamase-negative, ampicillin-intermediate or -resistant (BLNAR) strains represent a growing concern.
- Understanding the prevalence and resistance mechanisms of BLNAR strains is critical for effective treatment.
Purpose of the Study:
- To summarize the characteristics, prevalence trends, and current status of BLNAR strains of Haemophilus influenzae.
- To elucidate the mechanism of ampicillin resistance in these strains.
- To highlight the limitations of standard susceptibility tests and recommend confirmatory procedures.
Main Methods:
- Retrospective analysis of collected data on Haemophilus influenzae strains.
- Evaluation of standardized susceptibility testing methods.
- Review of beta-lactamase production and ampicillin susceptibility data.
Main Results:
- Ampicillin resistance in BLNAR strains is primarily due to alterations in penicillin-binding proteins (PBPs).
- Standardized tests may not reliably differentiate BLNAR from beta-lactamase-negative, ampicillin-susceptible (BLNAS) strains.
- Beta-lactamase-producing, ampicillin-resistant strains can be distinguished from BLNAS strains by standard tests.
Conclusions:
- Altered PBPs are the key mechanism for ampicillin resistance in BLNAR H. influenzae.
- Clinical laboratories must employ the MIC procedure to confirm ampicillin susceptibility and beta-lactamase activity in serious H. influenzae infections.
- Accurate differentiation is essential for appropriate antimicrobial therapy and infection control.