1989 Volume 37 Issue 12 Pages 1439-1452
During the 14 months from May 1985 to June 1986, enterococci were isolated from clinical materials at Chiba University Hospital.
During this period, 429 strains were collected, of which 309 were Enterococcus faecalis, 65 Enterococcus faecium, 52 Enterococcus avium, and 2 Enterococcus durans. Ampicillin (ABPC)-resistant strains (MIC:≥16μg/ml) were found in E. faecium, E. avium, and E. durans, but in E. faecalis no ABPC-resistant strains were found.
After this period, 2 ABPC-resistant strains were found in Enterococcus casselifiavus. E. faecium isolates were the most resistant of the enterococcal strains against β-lactams, and ABPC-resistant strains in all Enterococcus spp. were susceptible only to vancomycin. ABPC-resistant strains of Enterococcus spp. were mainly isolated from the patients who had polymicrobial infections, severe underlying diseases, and antibiotic premedication. Some characteristic differences were found between ABPC-susceptible (MIC:≤8μg/ml) and-resistant strains of E. faecium and E. avium.
In E. faecium, not all ABPC-susceptible strains fermented sorbitol, but 89.8% of ABPC-susceptible strains did; and in E. avium, most ABPC-resistant strains produced β-galactocidase and fermented raffinose, whereas few ABPC-susceptible strains showed those characteristics.
