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| |  Emerging Vancomycin Resistance in Staphlococci Detected NEW ORLEANS, Sept. 17, 1996 -- Possibly the first clinically significant blood culture isolate of "Staphylococcus epidermidis" to demonstrate decreased susceptibility to the antibiotic vancomycin has been detected using the Dade MicroScan(R) Automated Microbiology Testing System. The finding was publicly presented today for the first time by representatives from Dade International and Columbia Reston (Reston, Virginia) Hospital Center; they presented their report here, at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy. The reported discovery is believed to be significant because of the interest in "Staphylococcus" resistance to vancomycin, which is considered to be one of a few "last line of defense" antibiotics. The "Staphylococcus epidermidis" bacterium is always present on human skin and typically causes problems such as septicemia (blood infection) for patients whose health has been compromised from other medical conditions. "This finding is significant because of the medical community's increased interest in antibiotic resistance," said Barbara Zimmer, Ph.D., director of clinical and scientific affairs at Dade MicroScan. "We want to make sure that medical professionals are watching for "Staphylococcus epidermidis'' with increased resistance to vancomycin." The researchers reported that two strains of gram-positive cocci were isolated in June 1996 from two positive blood cultures drawn from the same patient five days apart at Columbia Reston Medical Center. The patient was a 50-year-old female with carcinoma of the gall bladder; she had an indwelling catheter and had received six weeks of vancomycin therapy. The strains were tested with the Dade MicroScan WalkAway(R) System on gram-positive test panels. Both samples were identified as "Staphylococcus epidermidis" and gave vancomycin MICs (minimal inhibitory concentrations) of 8 or 16, both of which are intermediate interpretations. Repeat testing produced the same results. The isolates were sent to Dade in Sacramento, California, for further evaluation. The Dade MicroScan reference lab tested the isolates on MicroScan(R) test panels, a frozen NCCLS reference panel, and by disk diffusion. The vancomycin result on the panels was again 8 and 16, and the disk diffusion was 17 mm-S. The identification was confirmed by conventional tube media. Because of the growing interest in the emergence of resistance to vancomycin in "Staphylococcus," the isolates were sent by Dade to the Centers for Disease Control in Atlanta. The intermediate vancomycin result and the identification were confirmed by the CDC. The tests of the two isolates found that one strain was susceptible to clindamycin and erythromycin and the other was resistant to both. Both strains were resistant to penicillin, oxacillin, ciprofloxacin and trimethoprim/sulfamethoxazole. The strains were susceptible to rifampin, tetracycline and chloramphenicol. "Dade is committed to providing accurate determination of susceptiblity to antimicrobial agents," said Judith Johnston, M.S., manager of the antibiotic susceptibility group at Dade MicroScan. "This finding is the best recent example why this commitment is so important." Dade International is headquartered in Deerfield, Illinois. The company has 5,500 employees in sales, research and manufacturing operations in 15 countries. The company provides products, systems and services for microbiology, clinical chemistry, hemostasis, clinical laboratory, quality control and cardiac immunodiagnostics.
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