Abstract: Methods and compositions are provided for identifying a group A Streptococcus in any of a variety of physiological samples, such as blood, saliva, throat swabs, cerebrospinal fluid, brocheolar lavage material, and biopsy material. The positions used include an extracellular cysteine protease or a fragment thereof, obtainable from S. pyogenes and containing at least one conserved epitope, or nucleic acid encoding the cysteine protease or fragment thereof. The compositions also find use in eliciting a protective immune response against a group A streptococcus infection.

Abstract: This invention relates to the identification, cloning, sequencing and characterization of the embCAB operon which determines mycobacterial resistance to the antimycobacterial drug ethambutol. The embCAB operon encodes the proteins which are the target of action of Mycobacterium tuberculosis, Mycobacterium smegmatis, and Mycobacterium leprae for ethambutol. The present invention provides purified and isolated embC, embA, and embB nucleic acids which comprise the embCAB operon, as well as mutated forms of these nucleic acids. The present invention also provides one or more single-stranded nucleic acid probes which specifically hybridize to the wild type embCAB operon or the mutated embCAB operon, and mixtures thereof, which may be formulated in kits, and used in the diagnosis of drug-resistant mycobacterial strain. The present invention also provides methods for the treatment and prevention of mycobacterial infections.