Interaction of clindamycin and gentamicin in vitro.

The minimal inhibitory concentrations of clindamycin and gentamicin alone and in combinations were determined by a microdilution method for 163 aerobic, facultative, and anaerobic clinical isolates. All 77 strains of Staphylococcus aureus, Diplococcus pneumoniae, Streptococcus pyogenes, and anaerobic bacteria (except for three strains of Clostridium) were inhibited by 1.6 mug or less of clindamycin per ml.

Morphology and ultrastructure of staphylococcal L colonies: light, scanning, and transmission electron microscopy.

Scanning electron microscopy utilizing critical point drying was used in parallel with light and transmission electron microscopy to study L colonies produced by a stable L-phase variant of Staphylococcus aureus (AH24H).

Light and scanning-beam electron microscopy of wall-defective Staphylococcus aureus induced by lysostaphin.

The serial morphological changes of Staphylococcus aureus after exposure to lysostaphin (one unit per ml) in hypertonic culture medium containing 5% NaCl were studied over an 8-hr period at 37 C. S. aureus stained gram-negative almost instantaneously upon contact with lysostaphin.

Scanning-beam electron microscopy of cell wall-defective staphylococci.

Staphylococci and their derived wall-defective forms (WDS) were studied with Gram stain, phase microscopy, and the scanning-beam electron microscope. Staphylococci were smooth, spherical, and relatively uniform in size. Stable WDS had corrugated surfaces and were larger; those prepared with lysostaphin were indistinguishable from those prepared with methicillin.