ANTIBIOGRAM PROFILING OF ISOGENIC IN VITRO-INDUCED VANCOMYCIN INTERMEDIATESUSCEPTIBLE AND PARENT SUSCEPTIBLE STAPHYLOCOCCUS AUREUS STRAINS

Staphylococcus aureus with reduced vancomycin susceptibility has become of concern in clinical treatment of infections. The study examined antibiogram profiles of in vitro generated isogenic clinical vancomycin intermediate-susceptible S. aureus (VISA) strains (n = 40) and heterogeneous (with sub-po...

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Published inSoutheast Asian journal of tropical medicine and public health Vol. 50; no. 3; pp. 522 - 529
Main Authors Lulitanond, Aroonlug, Khamparat, Prapaipak, Srinan, Sasikan, Wongthong, Sujintana, Sinlapasorn, Siwaporn, Sirichoat, Auttawit, Tavichakorntrakool, Ratree, Chanawong, Aroonwadee
Format Journal Article
LanguageEnglish
Published Bangkok Central Coordinating Board, SEAMEO-TROPMED Project 01.05.2019
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Summary:Staphylococcus aureus with reduced vancomycin susceptibility has become of concern in clinical treatment of infections. The study examined antibiogram profiles of in vitro generated isogenic clinical vancomycin intermediate-susceptible S. aureus (VISA) strains (n = 40) and heterogeneous (with sub-populations of VISA) (hVISA) strains (n = 7) compared to their respective parent vancomycin-susceptible (VSSA) strains. The vancomycin susceptibility categories were classified according to their minimum inhibitory concentration (MIC) to vancomycin using an agar dilution method together with a population analysis profile/area under curve assay. Isogenic parent and descendent S. aureus pairs were verified by pulsed-field gel-electrophoresis amplicon size profiles. Using a disc diffusion assay and MIC measurement, 28% of VISA were shown to become more sensitive to 10/12 other antimicrobials tested, in particular against (> 2 dilutions) amoxicillin/clavulanate, cefuroxime, penicillin, and oxacillin, while 29% of hVISA were more susceptible, but at a lesser extent, to this set of antibiotics. Interestingly 3 hVISA and 11 VISA strains exhibited higher resistance to teicoplanin than their respective parent VSSA strains. This study indicates antibiogram profiles of clinical vancomycin less-sensitive S. aureus strains should lead to identification of alternative antibiotics and/or their combinations that could provide more successful treatment outcome.
ISSN:0125-1562