Applications of flow cytometry to clinical microbiology

Classical microbiology techniques are relatively slow in comparison to othe r analytical techniques, in many cases due to the need to culture the micro organisms. Furthermore, classical approaches are difficult with unculturabl e microorganisms. More recently, the emergence of molecular biology techniq ues, particularly those on antibodies and nucleic acid probes combined with amplification techniques, has provided speediness and specificity to micro biological diagnosis Flow cytometry (FCM) allows single- or multiple-microb e detection in clinical samples in an easy, reliable, and fast way. Microbe s can be identified on the basis of their peculiar cytometric parameters or by means of certain fluorochromes that can be used either independently or bound to specific antibodies or oligonucleotides. FCM has permitted the de velopment of quantitative procedures to assess antimicrobial susceptibility and drug cytotoxicity in a rapid, accurate, and highly reproducible way. F urthermore, this technique allows the monitoring of in vitro antimicrobial activity and of antimicrobial treatments ex vivo. The most outstanding cont ribution of FCM is the possibility of detecting the presence of heterogeneo us populations with different responses to antimicrobial treatments. Despit e these advantages, the application of FCM in clinical microbiology is not yet widespread, probably due to the lack of access to flow cytometers or th e lack of knowledge about the potential of this technique. One of the goals of this review is to attempt to mitigate this latter circumstance. We are convinced that in the near future, the availability of commercial kits shou ld increase the use of this technique in the clinical microbiology laborato ry.