An instrument recently acquired by the University of Illinois Veterinary Diagnostic Laboratory is capable of matching microorganisms cultured from submissions against more than 5,600 distinct pathogens—bacteria, yeasts, and fungi —in the system’s database. And it takes only 90 minutes to identify up to 96 isolates.
Diagnostic techniques previously used to identify pathogens, in comparison, took from two days to more than a week, depending on the type of microorganism.
tremendous clinical tool
“The MALDI Biotyper is a tremendous clinical tool for veterinarians who need to quickly make a diagnosis and treatment decision for infections in animal patients, herds, or flocks,” says Dr. Carol Maddox, professor and veterinary microbiologist in the diagnostic laboratory.“And it can do the same for physicians,” she adds, “since the system’s database contains profiles on microorganisms of human and veterinary interest.”
The Veterinary Diagnostic Laboratory is the only fee-for-service diagnostic facility that offers this tool for microbial identification not only on the Urbana campus but within a 90-mile radius.
The MALDI Biotyper, manufactured by Bruker Daltonics Inc., detects the molecular mass of a microbe using laser ion scatter distance; the resulting protein profile—or “unique molecular fingerprint”—is immediately matched against the thousands of profiles in the system’s database. The machine completes this process for 96 different samples in 90 minutes.
The Case of the Cat with Crypto
One of the earliest cases to use the new system at the Illinois diagnostic laboratory involved a cat with an unusual urinary tract infection that was not responding to antibiotics. Initially laboratory personnel suspected that the system had made an error when it identified a yeast, Cryptococcus, as the infectious agent. A similar case appears only once in the scientific literature. Confirmed by DNA sequencing, the Illinois case will be presented at a scientific conference as an unexpected instance of this rare infection.
“Once we made this identification, the veterinarian quickly switched the patient’s prescription from antibiotics to anti-fungal medication,” explains Dr. Maddox “Identifying this agent using previous standard processes may have taken a week or longer as we ruled out suspect pathogens. That represents time the patient would not be receiving appropriate treatment.”
In another instance, it took less than a day to identify the cause of a respiratory illness that killed a calf with two types of pneumonia-causing bacteria. The laboratory received the lung biopsy in the afternoon, and by the next morning the veterinarian had the information needed to prescribe an effective antibiotic to protect other animals in the herd. In the past, it would have taken three days to accurately type these pathogens.
According to Dr. Maddox, most laboratories currently use identification systems that take hours or days and rely upon the oxidation-reduction, or fermentation of biochemical substrates that cause changes in indicator dyes when the test is positive.
Fast and Cost-Effective
Because the MALDI Biotyper is not only fast and accurate but also very cost-effective, less than one-tenth the cost of other common methods of identifying microorganisms, the instrument has many applications for users who need to analyze large numbers of samples very precisely.Functions of the system relevant for multiple samples include providing cluster analyses, for example, to aid public health investigators in conducting epidemiologic studies of disease outbreaks, and analyzing genetic mutations or variant strains of bacteria for biomedical researchers. The system’s library of stored profiles can be customized to evaluate novel microorganisms of interest for a particular study.
The system also aids clinicians by differentiating between anti-microbial resistant strains of bacteria and strains that are susceptible to antibiotics. That information is important in choosing the correct medication and combatting MRSA, methicillin resistant Staphylococcus infections.
The MALDI Biotyper was purchased by the veterinary college and diagnostic laboratory, with matching funds from the campus Office of the Vice Chancellor for Research. The instrument is expected to prove useful to numerous campus researchers as well as to the new College of Medicine announced earlier this year. Samples may be submitted from a wide range of clients, from veterinarians and physicians to researchers and public health officials.
For information about submitting samples to the state-of-the-art MALDI Biotyper at the University of Illinois Veterinary Diagnostic Laboratory, see the Microbiology section web page.