MEDICAL TECHNOLOGISTS USING MOLECULAR EPIDEMIOLOGY AS PART OF THE INFECTION CONTROL TEAM

Two medical technologists were appointed as permanent members of a new epidemiology section in the diagnostic microbiology laboratory of a l arge Veterans Administration Medical Center in the fall of 1989. These positions accounted for 9% of the total microbiology staff and were c reated on a temporary basis 2 years earlier from a need to have dedica ted technical expertise for use in the culture, isolation, and typing of nosocomial organisms. The technologists have evaluated outbreaks du e to Clostridium difficile, methicillin-susceptible Staphylococcus aur eus, and Serratia marcescens, and have begun work on a methicillin-res istant Staphylococcus aureus (MRSA)-typing scheme. Their major respons ibility has been the development and application of molecular biology techniques for the typing of nosocomial isolates, including restrictio n enzyme analysis of genomic DNA, plasmid profiling with and without r estriction enzyme analysis, ribosomal RNA probing of restricted genomi c DNA, and selected DNA sequencing of target organisms. Medical superv ision rests jointly between the directors of the infection control pro gram and the microbiology laboratory. During their tenure, infections due to C. difficile haze dropped from 95 cases per year to 57 cases an nually, treatment of MRSA colonization with systemic agents has been c urtailed, and a case control investigation involving S. marcescens was avoided. The inclusion of medical technologists in the infection cont rol practice of large medical care facilities, particularly with the a vailability of molecular epidemiologic techniques and the emergence of increasing numbers of multiply-drug-resistant pathogens, will become an essential component of these programs.