Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Types of interpretive errors in susceptibility testing. Zone breakpoints for norfloxacin disk diffusion testing.

A Björklind1, S Ringertz, G Kronvall

  • 1Department of Clinical Microbiology, Karolinska Hospital, Stockholm, Sweden.

APMIS : Acta Pathologica, Microbiologica, Et Immunologica Scandinavica
|October 1, 1989
PubMed
Summary
This summary is machine-generated.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Little difference between minimum inhibitory concentrations of Mycobacterium tuberculosis wild-type organisms determined with BACTEC MGIT 960 and Middlebrook 7H10.

Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases·2015
Same author

Epidemiological cut-off values for Flavobacterium psychrophilum MIC data generated by a standard test protocol.

Journal of fish diseases·2014
Same author

Effect of incubation temperature and time on the precision of data generated by antibiotic disc diffusion assays.

Journal of fish diseases·2014
Same author

Invasive disease caused by Haemophilus influenzae in Sweden 1997-2009; evidence of increasing incidence and clinical burden of non-type b strains.

Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases·2010
Same author

Socioeconomic factors and antibiotic use in relation to antimicrobial resistance in the Amazonian area of Peru.

Scandinavian journal of infectious diseases·2009
Same author

Two new dfr genes in trimethoprim-resistant integron-negative Escherichia coli isolates.

Antimicrobial agents and chemotherapy·2007

Norfloxacin susceptibility testing revealed errors in classifying common urinary tract pathogens. Adjusting species-specific minimum inhibitory concentration (MIC) limits can improve accuracy for both type I and type II errors.

Area of Science:

  • Clinical Microbiology
  • Antimicrobial Susceptibility Testing
  • Bacteriology

Background:

  • Accurate antimicrobial susceptibility testing is crucial for effective urinary tract infection (UTI) treatment.
  • Norfloxacin is a commonly prescribed fluoroquinolone for UTIs.
  • Discrepancies between MIC determinations and disk diffusion assays can lead to treatment errors.

Purpose of the Study:

  • To investigate errors in norfloxacin susceptibility testing for common UTI pathogens.
  • To compare MIC determinations with disk diffusion assays.
  • To propose corrections for identified interpretive errors.

Main Methods:

  • Evaluated 548 strains of eleven common UTI pathogens.
  • Compared Minimum Inhibitory Concentration (MIC) values with disk diffusion assays.

Related Experiment Videos

  • Analyzed susceptibility interpretations using NCCLS and SRGA standards.
  • Utilized single-strain regression analysis for error correction.

    • Main Results:

    • Enterobacteriaceae were generally susceptible to norfloxacin (MIC-90 < 1.0 mg/l).
    • Gram-positive bacteria, Pseudomonas aeruginosa, and nalidixic acid-resistant species showed lower susceptibility (MIC-90 > 1.0 mg/l).
    • Type I errors (reproducibility issues) were observed for S. faecalis, S. agalactiae, P. aeruginosa, and S. aureus.
    • A type II error (deviating regression line) was identified for S. saprophyticus.

    Conclusions:

    • Current norfloxacin susceptibility testing methods exhibit inaccuracies (type I and type II errors).
    • Introducing species-specific MIC limits is recommended to correct type I errors.
    • Species-specific interpretive breakpoints, derived from reference labs or single-strain analysis, can correct type II errors.