Molecular detection of antibiotic resistance: when and where?

Antibiotic resistance is a key issue affecting public health, and diagnostic bacteriology laboratories are essential for prompt recognition of resistant isolates. Determination of susceptibility or resistance using phenotypic tests is a 'gold standard' against which newer technologies are compared in terms of performance, cost and ease of use. Molecular methods for detecting resistance are myriad, and are used widely in academia and in reference laboratories, but gaining a significant foothold in diagnostic laboratories is proving more difficult. However, if used widely in a diagnostic setting, these techniques would impact more directly on patient care and would be valuable infection control tools, e.g. by rapidly confirming patients colonized by resistant bacteria. The cost of molecular assays may be considered prohibitive, and this is compounded by the daunting variety of proprietary platforms available; most diagnostic laboratories would prefer to invest their capital and to train their staff in a single versatile technology. In a market that has no clear leader, many laboratories are understandably reluctant to gamble on making the correct choice. If molecular detection of resistance is to achieve wide acceptance, manufacturers must broaden the repertoires of their technologies, develop more off-the-shelf applications with in-built quality control, and make them suitable for laboratory personnel with no specialist expertise in molecular biology.