Specific and universal probes and amplification primers to rapidly detect and identify common bacterial pathogens and antibiotic resistance genes from clinical specimens for routine diagnosis in microbiology laboratories

Abstract

The present invention relates to DNA-based methods for universal bacterial detection, for specific detection of the common bacterial pathogens Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Streptococcus pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Staphylococcus saprophyticus, Streptococcus pyogenes, Haemophilus influenzae and Moraxella catarrhalis as well as for specific detection of commonly encountered and clinically relevant bacterial antibiotic resistance genes directly from clinical specimens or, alternatively, from a bacterial colony. The above bacterial species can account for as much as 80% of bacterial pathogens isolated in routine microbiology laboratories. The core of this invention consists primarily of the DNA sequences from all species-specific genomic DNA fragments selected by hybridization from genomic libraries or, alternatively, selected from data banks as well as any oligonucleotide sequences derived from these sequences which can be used as probes or amplification primers for PCR or any other nucleic acid amplification methods. This invention also includes DNA sequences from the selected clinically relevant antibiotic resistance genes. With these methods, bacteria can be detected (universal primers and/or probes) and identified (species-specific primers and/or probes) directly from the clinical specimens or from an isolated bacterial colony. Bacteria are further evaluated for their putative susceptibility to antibiotics by resistance gene detection (antibiotic resistance gene specific primers and/or probes). Diagnostic kits for the detection of the presence, for the bacterial identification of the above-mentioned bacterial species and for the detection of antibiotic resistance genes are also claimed. These kits for the rapid (one hour or less) and accurate diagnosis of bacterial infections and antibiotic resistance will gradually replace conventional methods currently used in clinical microbiology laboratories for routine diagnosis. They should provide tools to clinicians to help prescribe promptly optimal treatments when necessary. Consequently, these tests should contribute to saving human lives, rationalizing treatment, reducing the development of antibiotic resistance and avoid unnecessary hospitalizations.

Description

BACKGROUND OF THE INVENTION [0001] Classical Identification of Bacteria [0002] Bacteria are classically identified by their ability to utilize different substrates as a source of carbon and nitrogen through the use of biochemical tests such as the API20E™ system. Susceptibility testing of Gram negative bacilli has progressed to microdilution tests. Although the API and the microdilution systems are cost-effective, at least two days are required to obtain preliminary results due to the necessity of two successive overnight incubations to isolate and identify the bacteria from the specimen. Some faster detection methods with sophisticated and expensive apparatus have been developed. For example, the fastest identification system, the autoSCAN-Walk-Away system™ identifies both Gram negative and Gram positive from isolated bacterial colonies in 2 hours and susceptibility patterns to antibiotics in only 7 hours. However, this system has an unacceptable margin of error, especially with ba...

AI Technical Summary

Benefits of technology

[0019] The development of hybridization (with either fragment or oligonucleotide probes) or of DNA amplification protocols for the detection of pathogens from clinical specimens renders possible a very rapid bacterial identification. This will greatly reduce the time currently required for the identification of pathogens in the clinical laboratory since these technologies can be applied for bacterial detection and identification directly from clinical specimens with minimum pretreatment of any biological specimens to release bacterial DNA. In addition to being 100% specific, probes and amplification primers allow identification of the bacterial species directly from clinical specimens or, alternatively, from an isolated colony. DNA amplific

Problems solved by technology

Although the API and the microdilution systems are cost-effective, at least two days are required to obtain preliminary results due to the necessity of two successive overnight incubations to isolate and identify the bacteria from the specimen.

However, this system has an unacceptable margin of error, especially with bacterial species other than Enterobacteriaceae (York et al., 1992.