Proof of Principle for Successful Characterization of Methicillin-Resistant Coagulase-Negative Staphylococci Isolated from Skin by Use of Raman Spectroscopy and Pulsed-Field Gel Electrophoresis

• Published in: Journal of Clinical Microbiology Vol. 48; no. 3; pp. 736 - 740
• Main Authors: Willemse-Erix, H.F.M, Jachtenberg, J, Barutçi, H, Puppels, G.J, van Belkum, A, Vos, M.C, Maquelin, K
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01-03-2010; American Society for Microbiology (ASM)
• Subjects: Bacterial Typing Techniques - methods; Bacteriology; Biological and medical sciences; Carrier State - microbiology; Cluster Analysis; DNA Fingerprinting - methods; Electrophoresis, Gel, Pulsed-Field - methods; Fundamental and applied biological sciences. Psychology; Humans; Methicillin Resistance; Microbiology; Reproducibility of Results; Skin - microbiology; Spectrum Analysis, Raman - methods; Staphylococcal Infections - microbiology; Staphylococcus - chemistry; Staphylococcus - classification; Staphylococcus - genetics; Staphylococcus - isolation & purification; Genotype; Pulsed field electrophoresis; Skin; Raman spectrometry
• ISSN: 0095-1137; 1098-660X
• DOI: 10.1128/JCM.01153-09

Coagulase-negative staphylococci (CNS) are among the most frequently isolated bacterial species in clinical microbiology, and most CNS-related infections are hospital acquired. Distinguishing between these frequently multiple-antibiotic-resistant isolates is important for both treatment and transmission control. In this study we used isolates of methicillin-resistant coagulase-negative staphylococci (MR-CNS) that were selected from a large surveillance study of the direct spread of MR-CNS. This strain collection was used to evaluate (i) Raman spectroscopy as a typing tool for MR-CNS isolates and (ii) diversity between colonies with identical and different morphologies. Reproducibility was high, with 215 of 216 (99.5%) of the replicate samples for 72 isolates ending up in the same cluster. The concordance with pulsed-field gel electrophoresis (PFGE)-based clusters was 94.4%. We also confirm that the skin of patients can be colonized with multiple MR-CNS types at the same time. Morphological differences between colonies from a single patient sample correlated with differences in Raman and PFGE types. Some morphologically indistinguishable colonies revealed different Raman and PFGE types. This indicates that multiple MR-CNS colonies should be examined to obtain a complete insight into the prevalence of different types and to be able to perform an accurate transmission analysis. Here we show that Raman spectroscopy is a reproducible typing system for MR-CNS isolates. It is a tool for screening variability within a collection of isolates. Because of the high throughput, it enables the analysis of multiple colonies per patient, which will enhance the quality of clinical and epidemiological studies.