Drug-Resistant Staphylococcus aureus Strains Reveal Distinct Biochemical Features with Raman Microspectroscopy

Oscar D. Ayala, Catherine A. Wakeman, Isaac J. Pence, Jennifer A. Gaddy, James C. Slaughter, Eric P. Skaar, Anita Mahadevan-Jansen

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Staphylococcus aureus (S. aureus) is a leading cause of hospital-acquired infections, such as bacteremia, pneumonia, and endocarditis. Treatment of these infections can be challenging since strains of S. aureus, such as methicillin-resistant S. aureus (MRSA), have evolved resistance to antimicrobials. Current methods to identify infectious agents in hospital environments often rely on time-consuming, multistep culturing techniques to distinguish problematic strains (i.e., antimicrobial resistant variants) of a particular bacterial species. Therefore, a need exists for a rapid, label-free technique to identify drug-resistant bacterial strains to guide proper antibiotic treatment. Here, our findings demonstrate the ability to characterize and identify microbes at the subspecies level using Raman microspectroscopy, which probes the vibrational modes of molecules to provide a biochemical "fingerprint". This technique can distinguish between different isolates of species such as Streptococcus agalactiae and S. aureus. To determine the ability of this analytical approach to detect drug-resistant bacteria, isogenic variants of S. aureus including the comparison of strains lacking or expressing antibiotic resistance determinants were evaluated. Spectral variations observed may be associated with biochemical components such as amino acids, carotenoids, and lipids. Mutants lacking carotenoid production were distinguished from wild-type S. aureus and other strain variants. Furthermore, spectral biomarkers of S. aureus isogenic bacterial strains were identified. These results demonstrate the feasibility of Raman microspectroscopy for distinguishing between various genetically distinct forms of a single bacterial species in situ. This is important for detecting antibiotic-resistant strains of bacteria and indicates the potential for future identification of other multidrug resistant pathogens with this technique.

Original languageEnglish (US)
Pages (from-to)1197-1210
Number of pages14
JournalACS infectious diseases
Issue number8
StatePublished - Aug 10 2018
Externally publishedYes


  • drug-resistant bacteria
  • identification
  • principal component analysis
  • quadratic discriminant analysis
  • Raman microspectroscopy
  • Staphylococcus aureus

ASJC Scopus subject areas

  • Infectious Diseases


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