Bone and joint infections are painful for patients and frustrating for both them and their doctors. The high success rates of antimicrobial therapy in most infectious diseases have not yet been achieved in bone and joint infections owing to the physiological and anatomical characteristics of bone. The key to successful management is early diagnosis, including bone sampling for microbiological and pathological examination to allow targeted and long-lasting antimicrobial therapy. The various types of osteomyelitis require differing medical and surgical therapeutic strategies. These types include, in order of decreasing frequency: osteomyelitis secondary to a contiguous focus of infection (after trauma, surgery, or insertion of a joint prosthesis); that secondary to vascular insufficiency (in diabetic foot infections); or that of haematogenous origin. Chronic osteomyelitis is associated with avascular necrosis of bone and formation of sequestrum (dead bone), and surgical debridement is necessary for cure in addition to antibiotic therapy. By contrast, acute osteomyelitis can respond to antibiotics alone. Generally, a multidisciplinary approach is required for success, involving expertise in orthopaedic surgery, infectious diseases, and plastic surgery, as well as vascular surgery, particularly for complex cases with soft-tissue loss.

An animal model involving the subcutaneous implantation of tissue cages into guinea pigs and subsequent infection with Staphylococcus aureus was used to study factors pertinent to foreign body infection. Whereas 10 8 colony-forming units (cfu) of S. aureus strain Wood 46 did not produce any abscesses in the absence of foreign material, 10 2 cfu was sufficient to infect 95070 of the tissue cages despite the presence of polymorphonuclear leukocytes (PMNLs) in sterile tissue cage fluid. Opsonization of S. aureus by tissue cage fluid was adequate during the first hour of infection, but opsonic coating of the organisms decreased at 20 hr after the induction of infection. PMNLs from sterile tissue cage fluid showed decreased phagocytic and bactericidal activities when compared with PMNLs from either blood or peritoneal exudate obtained after short-or long-term stimulation (P < 0.001).The enhanced risk of bacterial infections in the vicinity of a foreign body -such as sutures and metallic or polymeric implants -has been repeatedly documented in cardiovascular [1][2][3], orthopedic [4][5][6], plastic reconstructive [7], and general [8] surgery. Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli are most frequently implicated as the etiologic agents [9]. Foreign body infection proceeds by two possible routes: early infection, due to local bacterial contamination during surgery [4], and late infection, after occasional seeding of microorganisms by the hematogenous route [6]. Both types of infections, once established, rarely heal, and excision of the foreign body remains the only effective treatment.

No abstract

Bacterial adherence to polymer surfaces is a required early step in intravenous (iv) device infection. Wecollected eight strains of Staphylococcus aureus and 19of coagulase-negative staphylococci from patients with proven iv device bacteremia and studied the role of plasma or connective-tissue proteins in promoting bacterial adherence to polymethylmethacrylate (PMMA) coverslips. Although only a negligible percentage of organisms adhered to albumin-coated PMMA, surface-bound fibronectin significantly promoted adherence of all isolates. Fibrinogen markedly promoted adherence of all S. aureus strains but of only four coagulase-negative strains. Thus, coagulase-negative staphylococci revealed a marked heterogeneity in adherence to fibrinogen-coated surfaces, a result suggesting the existence of heretofore unknown receptors for fibrinogen. Laminin promoted adherence of staphylococci to a much lower extent. Although strain specific, adherence of clinical staphylococcal isolates to foreign surfaces is significantly increased by fibronectin, fibrinogen, and laminin, an observation suggesting the possible contribution of these proteins to the pathogenesis of iv device infection.Adherence of microorganisms to specific substrates is presently considered to be a crucial step in the initiation of infections [1]. Many investigators have searched for such ligands in staphylococcal prosthesis infection. There is increasing evidence that similar specific interactions might also playa role in the pathogenesis of foreign-body infections.After contact with blood, a polymer surface (such as a cannula inserted iv) is almost immediately coated with a protein layer at the blood-polymer interface [2][3][4]. Bacterial adherence to the protein-coated surface is a prerequisite for initiating iv device infection. Fibrinogen and fibronectin are proteins known to bind and to aggregate staphylococci [5,6]. More recently, laminin, a large glycoprotein mainly found Receivedfor publication 2 December 1987and in revised form 7 April 1988. This paper was presented in part at the 27th Interscience Conference on Antimicrobial Agents and Chemotherapy (abstract 503), held on 4-7 October 1987, in New York, New York.This work was supported by grant 3.829-0.87 from the Swiss National Research Foundation.We thank Elzbieta Huggler for technical assistance, Dr. Ingeborg Filthuth and Chantal Genier for isolation and characterization of the bacterial isolates, and Paule Schilling-Doriot for manuscript preparation.Please address requests for reprints to Dr. Mathias Herrmann, Infectious Diseases Division, Department of Medicine, University Hospital, CH-1211 Geneva 4, Switzerland. 693in basal membranes and to a slight extent in plasma, has also been described as possessing staphylococcalbinding properties [7]. Several studies have investigated staphylococcal adherence [8][9][10][11] to polymer surfaces. In particular, studies performed on explanted foreign bodies [12,13]and on in vitro models [14,15]strongly suggested that adherence of selected staphylococcal str...

No abstract