European multicentre evaluation of a commercial system for identification of methicillin-resistant Staphylococcus aureus.

A commercial system for the rapid detection of methicillin-resistant Staphylococcus aureus, the BBL Crystal MRSA test (C-MRSA ID; Becton Dickinson, USA), was evaluated prospectively and compared with a polymerase chain reaction test for the presence of the mecA gene. Ten European centres tested a total of 676 isolates of Staphylococcus aureus from blood cultures. The system correctly identified 661 (97.8%) isolates within 4 h. All but three mecA gene-negative isolates (99.4% specificity) yielded a negative C-MRSA ID reaction, and 158 of 170 mecA gene-positive isolates were accurately detected (92.9% sensitivity). After repeated testing of discrepant results, sensitivity and specificity increased to 99% and 100%, respectively.

[Propionate negative saccharolytic bacteroides strains (B. oralis)-occurrence, identification, antimicrobial susceptibility and serological behaviour (author's transl)]. / Propionatnegative saccharolytische Bacteroides-Stämme (B. oralis)-Vorkommen, Identifizierung, Chemotherapeutika-Empfindlichkeit und serologisches Verhaltin

Twenty-three propionate negative non-pigmented Bacteroides strains were isolated from mixed infections (peritonitis, endometritis, abscess of the abdominal wall etc.) as well as vaginal secretions of healthy parturients in the course of 3 years. The cultures were indole negative, produced acetic, isobutyric and isovaleric acids and had a final pH of 5.0-5.5 in glucose broth; they were assigned to B. oralis as described by LOESCHE and coworkers in 1964. tpathogenic significance of this organism may be assumed in those cases of mixed infection where the microbial association consisted solely of gram-positive species with low virulence (lactobacilli, Staphylococcus epidermidis, Peptococcaceae). Antibiotic susceptibility of 12 B. oralis strains was studied by tube dilution tests. Resistance to cephalosporins was detected in 8 strains, about half of them were resistant to ampicillin and penicillin G. Like other Bacteroides species, the B. oralis strains showed resistance to aminoglycosides and sensitivity to clindamycin, chloramphenicol and erythromycin. The serological behaviour of 9 B. oralis strains was studied in cross-agglutinationation and gel-diffusion experiments. Cross-reactivity was particularly pronounced in immunodiffusion tests with autoclaved extracts. According to the results obtained, the strains belonged to a homogeneous group with 1-2 identical antigens. These B. oralis antigens were shared by B. melaninogenicus ss. intermedius 2965. There were, however, no cross-reactions between the aforementioned strains and B. melaninogenicus ss. melaninogenicus 8117/1. The taxonomic implications of a close relationship between B. oralis and B. melaninogenicus ss. intermedius are discussed.

Susceptibility to erythromycin of anaerobes of the genera Bacteroides, Fusobacterium, Sphaerophorus, Veillonella, Clostridium, Corynebacterium, Peptococcus, Peptostreptococcus.

The minimal inhibitory concentrations (MIC) of erythromycin were determined by broth dilution tests for 313 anaerobic strains, most of which were clinical isolates. All the gram-positive anaerobes tested (84 Peptococcaceae, including 21 Peptostreptococcus anaerobius and 15 Peptococcus variabilis; 65 Corynebacterium acnes and 29 Clostridium strains, including 13 C. perfringens) were sensitive (MIC values 0.012 through 3.12 microgram erythromycin/ml); so were 111 cultures of gram-negative anaerobes (52 Bacteroides fragilis, 12 B. thetaiotaomicron, 7 B. vulgatus, 13 B. oralis, 4 B. melaninogenicus, 10 Sphaerophorus necrophorus, 2 Veillonella sp., 11 members of other species). Erythromycin at concentrations of 6.25 through 200.0 microgram/ml was active against 24 strains (1 B. fragilis, 4 Fusobacterium fusiforme, 9 Sph. freundi, 10 Sph. varius). The present results are compared to the limited number of reports existing with regard to the susceptibility of anaerobes to erythromycin.