Comparison of multiple antibiotic resistant Staphylococcus aureus genomes and the genome structure of Elizabethkingia meningoseptica

Abstract

i. The aim of this study was to determine if methicillin-resistant Staphylococcus aureus (MRSA) strains could be identified in the milk of dairy cattle in a Paso Del Norte region dairy. Using physiological and PCR-based identification schemes, 40 S. aureus strains were isolated from 133 milk samples analyzed. This investigation also included the production of draft genome sequences of a MRSA and a methicillin-susceptible isolate. Genomic analysis of these strains demonstrate that strains H29 and PB32 represent novel clones of sequenced human and/or bovine-related strains of S. aureus.

ii. The draft genomes of a heterogeneous vancomycin-intermediate resistant Staphylococcus aureus (VISA) strain MM66 and strain MM66RVI-4 expressing reduced vancomycin-intermediate resistance harbored the same mutation in grass of a two-component regulatory system. MM66RVI-4 has also lost staphylococcal cassette chromosome, Scene, corroborating methicillin-resistance in this strain and harbored mutations present in rag, encoding an ATP-binding cassette transporter. The observed genetic alterations in both strains have been shown to affect vancomycin resistance levels in VISA.

iii. Elizabethkingia species are environmental isolates that exhibit a multidrug-resistance phenotype and are a cause of life-threatening infections in immunocompromised individuals. To date, most studies have focused on the clinical aspects of this organism, and little is known regarding its antimicrobial resistance mechanisms. In addition, the phylogenetics and speciation of this genus is still highly controversial and has yet to be thoroughly defined. In an effort to clear up confusion surrounding the speciation of this genus as well as identifying possible antimicrobial resistance mechanisms, we report the draft genome sequence of the E. meningoseptica type strain ATCC 13253T.