Cell wall alterations in staphylococci growing in situ in experimental osteomyelitis

Abstract

When cells of both Staphylococcus aureus and Staphylococcus epidermidis are grown in batch culture in nutrient-rich media, their cell walls are regular in thickness, their cell size is within the normal range for each species, and their septation patterns are orderly. When cells of each of these species are examined directly in infected tissue in the rabbit tibia model infection, their cell wall thickness is often much increased and very irregular around the circumference of the cell, their cell size is often increased, and their septation patterns are often severely deranged. All of these alterations in cell wall structure occur in the absence of antibiotics, and we suggest that they may be an expression of phenotypic plasticity in response to altered environmental conditions such as specific nutrient limitations, the presence of antibacterial factors, and growth of the cells on hard surfaces such as rabbit bone or plastic catheters. Some of these specific cell wall alterations are also seen when staphylococcal cells are exposed, in vitro or in vivo, to antibiotics such as clindamycin, but we emphasize that growth in tissue alone is sufficient for their induction.

Inactivation of a subpopulation of human neutrophils by exposure to ultrahigh-molecular-weight polyethylene wear debris

“…Phagocytic mixtures containing neutrophils preincubated with UHMWE wear particles and/or S. aureus suspensions, prepared as described above, were centrifuged and each pellet was suspended in sodium cacodylate buffer (0.1 M, pH 7.2) supplemented with 2.5 mM CaCl 2 , 5 mM MgCl 2 and 0.1 M sucrose, and fixed with 2.5% glutaraldehyde for 1 h at room temperature or overnight at 4°C (Costerton et al , 1987). Then, the fixed material was washed twice in cacodylate buffer, postfixed for 1 h at room temperature in 2 mL 1% osmium tetroxide in the same buffer, then embedded in Epon and sectioned.…”

Intracellular Staphylococcus aureus and antibiotic resistance: Implications for treatment of staphylococcal osteomyelitis

“…aureus cells were grown overnight in TSB and the culture was washed two times with HBSS and prepared TEM. 28 For intracellular S. aureus, bacteria from three wells were released after time 0, 6, 12, and 24 h (as described above) and harvested by centrifugation. The resulting pellets were washed two times with HBSS and samples were prepared for TEM as described.…”

Pharmacokinetic and pharmacodynamic requirements for antibiotic therapy of experimental endocarditis

“…Fibrin is a regular component of the inflammatory process which accompanies many infections. Ultrastructural alterations of organisms suggesting reduced metabolic activity have been described in chronic refractory infections, such as experimental osteomyelitis (16). Glycocalyx-enclosed biofilms of bacteria have also been identified in experimental or clinical infections that arise from osteomyelitis or contaminated prostheses (15).…”