COMPARISON OF ETEST AND AGAR DILUTION FOR DETERMINING MINIMUM INHIBITORY CONCENTRATION OF VANCOMYCIN TO HEALTHCARE-ASSOCIATED METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS

Authors

  • Jyoti Kumari
  • Shalini Shenoy m
  • Chakrapani M
  • Vidyalakshmi K
  • Gopalkrishna Bhat k Addtional ProfessorDept. of MicrobiologyKasturba Medical CollegeMangalore-575001

Abstract

ABSTRACT
Objectives: To compare agar dilution method and Etest in the determination of minimum inhibitory concentration (MIC) of vancomycin to healthcareassociated
methicillin-resistant
Staphylococcus
aureus
(HA-MRSA).
Methods: A total of 98 non-duplicate strains of HA-MRSA isolated from different clinical specimens were tested for their antibiotic susceptibility
pattern by Kirby-Bauer disk diffusion method and vancomycin MIC by agar dilution method and Etest (BioMerieux, France).
Results: Out of 98 strains of HA-MRSA, 94 (95.9%) were vancomycin susceptible (MIC ≤2 µg/ml and 4 (4.1%) were vancomycin intermediate (MIC
4 µg/ml) by agar dilution method. By Etest, 53 (54.1%) were vancomycin susceptible, 4 (4.1%) were vancomycin intermediate, and the remaining 41
isolates had vancomycin MIC between 2 µg/ml and 4 µg/ml.
Conclusion: Etest allows the detection of HA-MRSA strains with intermediate MIC values in addition to traditional dilutions. These properties will
help in detection of MIC creep and also decision-making in using vancomycin for the treatment of serious infections caused by HA-MRSA.
Keyword: Vancomycin, Minimum inhibitory concentration, Etest, Agar dilution.

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References

REFERENCES

Liu C, Bayer A, Cosgrove SE, Daum RS, Fridkin SK, Gorwitz RJ,

et al. Clinical practice guidelines by the infectious diseases society

of America for the treatment of methicillin-resistant Staphylococcus

aureus infections in adults and children: Executive summary. Clin

Infect Dis 2011;52(3):285-92.

Howden BP, Davies JK, Johnson PD, Stinear TP, Grayson ML. Reduced

vancomycin susceptibility in Staphylococcus aureus, including

vancomycin-intermediate and heterogeneous vancomycin-intermediate

strains: Resistance mechanisms, laboratory detection, and clinical

implications. Clin Microbiol Rev 2010;23(1):99-139.

Jones RN. Microbiological features of vancomycin in the 21

century:

Minimum inhibitory concentration creep, bactericidal/static activity,

and applied breakpoints to predict clinical outcomes or detect resistant

st

Asian J Pharm Clin Res, Vol 9, Issue 4, 2016, 189-191

Kumari et al.

strains. Clin Infect Dis 2006;42 Suppl 1:S13-24.

Dhand A, Sakoulas G. Reduced vancomycin susceptibility among

clinical Staphylococcus aureus isolates (‘the MIC Creep): Implications

for therapy. F1000 Med Rep 2012;4:4.

Hsu DI, Hidayat LK, Quist R, Hindler J, Karlsson A, Yusof A, et al.

Comparison of method-specific vancomycin minimum inhibitory

concentration values and their predictability for treatment outcome of

meticillin-resistant Staphylococcus aureus (MRSA) infections. Int J

Antimicrob Agents 2008;32(5):378-85.

Tandel K, Praharaj AK, Kumar S. Differences in vancomycin MIC

among MRSA isolates by agar dilution and E test method. Indian J Med

Microbiol 2012;30(4):453-5.

Prakash V, Lewis JS 2

, Jorgensen JH. Vancomycin MICs for

methicillin-resistant Staphylococcus aureus isolates differ based upon

the susceptibility test method used. Antimicrob Agents Chemother

;52(12):4528.

nd

Chaudhari CN, Tandel K, Grover N, Bhatt P, Sahni AK, Sen S, et al.

In vitro vancomycin susceptibility amongst methicillin resistant

Staphylococcus aureus. Med J Armed Forces India 2014;70(3):215-9.

Centers for Disease Control and Prevention. CDC/NHSN Surveillance

Definition for Specific Types of Infection. Available from: http://

www.cdc.gov/nhsn/pdfs/pscmanual/17pscnosinfdef-current.pdf. [Last

accessed on 2015 Nov 13].

Bannerman TL. Staphylococci and other catalase positive cocci that

grow aerobically. In: Murray PR, Baron EJ, Jorgenson JH, editors.

Manual of Clinical Microbiology. 8

ed. Washington, DC: ASM Press;

p. 384-404.

th

Clinical and Laboratory Standards Institute. Performance Standards

for Antimicrobial Susceptibility Testing; Twenty Fifth Informational

Supplement. CLSI Document M100-S25. Wayne, PA: CLSI; 2015.

Clinical and Laboratory Standards Institute. Performance Standards for

Antimicrobial Susceptibility Testing; Twenty – Second Informational

Supplement. CLSI Document M100-S22. Wayne: CLSI; 2012.

Rybak MJ, Vidaillac C, Sader HS, Rhomberg PR, Salimnia H,

Briski LE, et al. Evaluation of vancomycin susceptibility testing for

methicillin-resistant Staphylococcus aureus: Comparison of E test and

three automated testing methods. J Clin Microbiol 2013;51(7):2077-81.

Himani CA, Madan M, Pandey A, Thakuria B. Methicillin resistant

Staphylococcus aureus: Inconsistencies in vancomycin susceptibility

testing methods limitations and advantages of each. J Clin Diagn Res

;9(10):DC01-4.

Campana EH, Carvalhaes CG, Nonato B, Machado AM, Gales AC.

Comparison of M.I.C.E. and Etest with CLSI agar dilution for

antimicrobial susceptibility testing against oxacillin-resistant

Staphylococcus spp. PLoS One 2014 14;9(4):e94627.

Swenson JM, Anderson KF, Lonsway DR, Thompson A, McAllister SK,

Limbago BM, et al. Accuracy of commercial and reference susceptibility

testing methods for detecting vancomycin-intermediate Staphylococcus

aureus. J Clin Microbiol 2009;47(7):2013-7.

Craig WA. Basic pharmacodynamics of antibacterials with clinical

applications to the use of beta-lactams, glycopeptides, and linezolid.

Infect Dis Clin North Am 2003;17(3):479-501.

Rybak MJ. The pharmacokinetic and pharmacodynamic properties of

vancomycin. Clin Infect Dis 2006;42 Suppl 1:S35-9.

Moise-Broder PA, Forrest A, Birmingham MC, Schentag JJ.

Pharmacodynamics of vancomycin and other antimicrobials in patients

with Staphylococcus aureus lower respiratory tract infections. Clin

Pharmacokinet 2004;43(13):925-42.

Kullar R, Davis SL, Levine DP, Rybak MJ. Impact of vancomycin

exposure on outcomes in patients with methicillin-resistant

Staphylococcus aureus bacteremia: Support for consensus guidelines

suggested targets. Clin Infect Dis 2011;52(8):975-81.

Mohr JF, Murray BE. Point: Vancomycin is not obsolete for the

treatment of infection caused by methicillin-resistant Staphylococcus

aureus. Clin Infect Dis 2007;44(12):1536-42.

Published

01-07-2016

How to Cite

Kumari, J., S. Shenoy m, C. M, V. K, and G. Bhat k. “COMPARISON OF ETEST AND AGAR DILUTION FOR DETERMINING MINIMUM INHIBITORY CONCENTRATION OF VANCOMYCIN TO HEALTHCARE-ASSOCIATED METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS”. Asian Journal of Pharmaceutical and Clinical Research, vol. 9, no. 4, July 2016, pp. 189-91, https://mail.innovareacademics.in/journals/index.php/ajpcr/article/view/11956.

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