18/9/4 (Item 4 from file: 155)

09725831 98432974

Application of a rat osteomyelitis model to compare in vivo and in vitro the antibiotic efficacy against bacteria with high capacity to form biofilms.

Gracia E; Lacleriga A; Monzon M; Leiva J; Oteiza C; Amorena B

J Surg Res ( UNITED STATES ) Oct 1998 , 79 (2) p146‑53 , ISSN

A rat experimental osteomyelitis model was used to study the efficiency of antibiotics on biofilm bacteria adhered to implants in relation to the efficiency obtained in vitro. In the osteomyelitis model, 10(4) bacteria of the strain variant used for the in vitro studies (a slime‑producing variant of Staphylococcus aureus) were inoculated into the rat tibia at surgery, after implanting a stainless steel canula precolonized for 12 h with this strain. After 5 weeks, a 21‑day antibiotic treatment was applied (using cefuroxime, vancomycin, or tobramycin). Subsequently, implant and tibia were studied for presence of bacteria. In this osteomyelitis model, cefuroxime inhibited bone colonization and reduced the number of bacteria in metal and bone at a higher degree (P < 0.05) than vancomycin and trobramycin (the latter antibiotic did not have this reduction effect). The in vitro assay was applied using three concentrations of each antibiotic (8, 100, and 500 microg/ml) and 6‑, 24‑, and 48‑h biofilms. Bacterial viability was evaluated by ATP‑bioluminescence after 24 h of antibiotic treatment. In this in vitro assay, cefuroxime significantly (P < 0.05) reduced in all cases the number of viable bacteria in biofilms, tobramycin did not affect viability, and vancomycin affected viability except at the lowest concentration used (8 microg/ml, i.e., 8x the minimal bactericidal concentration of this antibiotic) when facing the oldest (48 h) biofilm. These results demonstrate the usefulness of the osteomyelitis model applied in providing evidence for a close correlation between the in vitro and in vivo findings on the effect of three antibiotics under study. Copyright 1998 Academic Press.

18/9/71 (Item 11 from file: 73)

07737775 EMBASE No: 1999220274

Mechanisms of Staphylococcus aureus invasion of cultured osteoblasts

Ellington J.K.; Reilly S.S.; Ramp W.K.; Smeltzer M.S.; Kellam J.F.; Hudson M.C.

Microbial Pathogenesis ( MICROB. PATHOG. ) ( United Kingdom ) 1999, 26/6 (317‑323)

Staphylococcus aureus is a bacterial pathogen causing approximately 80% of all cases of human osteomyelitis. This bacterium can adhere to and become internalized by osteoblasts and previous studies indicate that osteoblasts are active in the internalization process. In the current study, we examined the roles of microfilaments, microtubules and clathrin‑dependent receptor‑mediated endocytosis in the internalization of S. aureus by MC3T3‑E1 mouse osteoblast cells. Microfilament and microtubule polymerization was inhibited with cytochalasin D and colchicine. Clathrin‑coated pit formation was examined by using the transaminase inhibitor, monodanslycadaverine. The results of this study indicate that mouse osteoblasts utilize actin microfilaments, microtubules and clathrin‑coated pits in the internalization of S. aureus; however, microfilaments seem to play the most significant role in the invasion process.

18/9/267 (Item 14 from file: 5)

08228498 Biosis No.: 000094029462

Excretion of urinary hydroxyproline in correlation with severity of induced osteomyelitis in rabbits

Author: ABBAS H L

Journal: ACTA PHYSIOL HUNG 78 (3). 1991. 235‑239.

Abstract: Osteomyelitis was induced artificially by injecting Staphylococcus aureus culture in the tibiae of young rabbits. Weekly estimations of hydroxyproline in urine were done for six weeks. It was found that the osteomyelitic rabbits excreted more hydroxyproline (about 96%) two weeks after the infection in comparison to the control animals and it continued to be very high (about 138%) six weeks after the infection. The results indicate that urinary hydroxyproline reflects degradation of collagen fibers in the bone, and may be an indicator of the severity of the disease.