Simple rapid tests for presumptive identification of catalase-negative non-beta-hemolytic cocci (i.e., enterococci, leuconostocs, and pediococci) have not previously been available. Seven hundred thirty-four strains of aerobic and facultatively anaerobic, catalase-negative, non-beta-hemolytic gram-positive cocci were tested for susceptibility to vancomycin (Van s) by a screening procedure and production of leucine aminopeptidase (LAPase) and pyrrolidonylarylamidase (PYRase) in disk tests. Three unique patterns of activity in response to the three disks (30 g of vancomycin, PYRase, and LAPase) can be used to presumptively identify the vancomycin-resistant (Van r) enterococci (Van r and PYRase and LAPase positive), leuconostocs (Van r and PYRase and LAPase negative), and pediococci (Van r , PYRase negative, and LAPase positive). The results indicate that, together with Gram stain characteristics and the catalase test, the vancomycin, LAPase, and PYRase disk tests can be used to presumptively identify Van r strains of enterococci as well as Leuconostoc and Pediococcus strains from human infections.
Acute gastroenteritis is known to cause millions of deaths worldwide, many of which are attributable to viral agents. Death is caused by cardiac arrest as a result of dehydration and electrolytic imbalance brought on by vomiting and diarrhea. The majority of these deaths occur in developing countries where public sanitation and health care is at a minimum. Deaths from gastroenteritis in the United States have dropped considerably since the 1900's because of improvements in health care.Viruses may be identified as the pathological agent of gastroenteritis by a variety of methods, one of which is morphological identification by electron microscopy (EM). Electron microscopy offers a rapid method for identifying viruses regardless of serotype, but requires a concentration of viral particles of between 105- 106/ml to be effective. This concentration problem can be overcome by ultracentrifu-gation, although detection of Norwalk Agent requires immuno-electron microscopy.
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