Performance of vancomycin and teicoplanin disk diffusion test in isogenic vancomycin non-susceptible Staphylococcus aureus

  • Sujintana Wongthong Graduate School, Khon Kaen University, Khon Kaen, Thailand
  • Karnjana Dutchanutouch Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
  • Viladda Namsaengkang Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
  • Aroonwadee Chanawong Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
  • Chotechana Wilailuckana Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
  • Aroonlug Lulitanond Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
Keywords: Staphylococcus aureus, vancomycin resistance, teicoplanin, induction, PAP-AUC

Abstract

Introduction: Detection of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) is currently problematic. Although the population analysis profile with area under the curve (PAP-AUC) is the gold standard for detecting hVISA strains, this method is time consuming. This study aimed to induce vancomycin non-susceptible Staphylococcus aureus isolates in methicillin-resistant S. aureus (MRSA) and to determine the performance of the vancomycin and teicoplanin disk diffusion test for screening of induced and natural vancomycin non-susceptible isolates.

Methodology: Vancomycin resistance was induced in vitro in methicillin-resistant S. aureus by serial passage in media with increasing vancomycin concentrations. All test isolates were confirmed for their susceptibility to vancomycin by using a PAP-AUC method. The performance of the vancomycin and teicoplanin disk diffusion test for detecting both induced and natural hVISA/VISA isolates was analyzed using the MedCal program version 10.2.0.

Results: The induction test revealed that 42 of 78 MRSA isolates (53.8%) became hVISA and/or VISA. Using 10, 15, 20, 30 µg vancomycin disks and a 30 µg teicoplanin disk, the highest performance (88.9%) for hVISA/VISA detection (71.1%, sensitivity, 100% specificity, 100% positive predictive value, and 75% negative predictive value) was obtained when a 20 µg vancomycin disk was used at 1.0 McFarland inoculum for a 24-hour incubation.

Conclusions: The results indicated that using a 20 µg vancomycin disk and bacterial inoculum of 1.0 McFarland is simple to perform and provides a primary result for hVISA/VISA screening within 24 hours.

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Author Biographies

Sujintana Wongthong, Graduate School, Khon Kaen University, Khon Kaen, Thailand
  • Graduate Student of the Degree of Master of Science in Medical Technology.
  • Infectious Diseases Research Group, Department of Microbiology,Faculty of Associated Medical Sciences, Khon kaen University,Khon Kaen
Karnjana Dutchanutouch, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
  • The 4th year student, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen.
Viladda Namsaengkang, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
The 4th year student, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen.
Aroonwadee Chanawong, Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
  • Antimicrobial resistance in Gram-negative bacilli
  • Methods of isolation and identification of bacteria
  • Antimicrobial resistance: molecular epidemiology
  • Infectious Diseases Research Group, Department of Microbiology,Faculty of Associated Medical Sciences, Khon kaen University,Khon Kaen.
Chotechana Wilailuckana, Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
  • Antimicrobial resistant bacteria
  • Lab diagnosis and identification of aerobic and anaerobic bacteria
  • MRSA: methicillin-resistant Staphylococcus aureus
  • Infectious Diseases Research Group, Department of Microbiology,Faculty of Associated Medical Sciences, Khon kaen University,Khon Kaen.
Aroonlug Lulitanond, Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
  • Antimicrobial resistant bacteria
  • Lab diagnosis and identification of aerobic and anaerobic bacteria
  • Infectious Diseases Research Group, Department of Microbiology,Faculty of Associated Medical Sciences, Khon kaen University,Khon Kaen.
Published
2015-02-19
How to Cite
1.
Wongthong S, Dutchanutouch K, Namsaengkang V, Chanawong A, Wilailuckana C, Lulitanond A (2015) Performance of vancomycin and teicoplanin disk diffusion test in isogenic vancomycin non-susceptible Staphylococcus aureus. J Infect Dev Ctries 9:157-164. doi: 10.3855/jidc.5059
Section
Original Articles