Porphyrin test as an alternative to benzidine test for detecting cytochromes in catalase-negative gram-positive cocci.

A total of 66 strains of gram-positive cocci, including 21 catalase-negative members of the family Streptococcaceae and strains of Stomatococcus mucilaginosus, were investigated for the ability to produce porphobilinogen and porphyrin from delta-aminolevulinic acid as an alternative to the benzidine test for detecting the presence of cytochromes. Production of porphobilinogen correlated 100% with membership in the family Micrococcaceae.

Investigation of Micrococcaceae in a department of cardiac surgery. Biochemical characterization and sensitivity patterns of strains isolated from patients, staff, and air.

A total of 965 strains of Micrococcaceae isolated from 200 patients, personnel, and air in a department of cardiac surgery were classified by means of Baird-Parker's scheme. The majority of strains were identified as Staphylococcus epidermidis (S. epidermidis) biotype 1, but S. epidermidis biotype 4 accounted for c. 25% of isolates from patients post-operatively. Pre-operative isolates were generally sensitive to most antibiotics tested while post-operative strains of coagulase-negative Micrococcaceae from patients and isolates from personnel and air were frequently multiply-resistant. Strains of Staphylococcus aureus (S. aureus) were sensitive or resistant only to penicillin. More patients were colonized with coagulase-negative Micrococcaceae after operation than at admission to the hospital (p less than 0.001), while the frequency of S. aureus carriers was the same before and after operation and equal to the frequency found earlier. The frequency of S. aureus carriers among the personnel, however, was lower than reported earlier (10%). Multiply-resistant strains of S. epidermidis seem to have replaced resistant strains of S. aureus as the predominant hospital saprophyte among Micrococcaceae.

[Firefly assay of bacterial ATP: comparative study of extraction methods (author's transl)]. / Mesure de l'ATP bactérien par bioluminescence: étude critique des méthodes d'extraction.

The firefly bioluminescence ATP assay presents multiple applications in microbiological analysis. Nine ATP extraction methods were tested on thirteen Gram positive and Gram negative bacterial species. The DMSO method appears as the procedure for choice. It provides the highest yields and the best reproducibility, even at high bacterial concentrations. It is simple, rapid and can be recommended for routine analysis. Assays carried out after extraction by this procedure show that in 24 hours cultures, the ATP content ranges from 0.28 fg to 15.65 fg per cell depending on species.

Occurrence of glutathione in bacteria.

Glutathione and soluble thiol content were examined in a broad spectrum of bacteria. Significant soluble thiol was present in all cases. The thiol compound was glutathione in most of the gram-negative bacteria but not in most of the gram-positive bacteria studied. Glutathione was absent in four anerobes and one microaerophile but was present in a blue-green bacterium. The glutathione content of Escherichia coli increased significantly during transition from exponential to stationary phase.