Diagnosis and management of staphylococcal infections of vascular grafts and stents

Abstract

Staphylococcus aureus and coagulase-negative staphylococci are the commonest bacterial causes of both vascular graft and stent infections. Infection may occur either from direct implantation or haematogenous spread, and occurs in less than 1% of aortic grafts, 2% to 5% of inguinal grafts, and rarely in stents. Death or amputation is common following these infections despite aggressive treatment. Infection with S. aureus is usually more acute than with coagulase-negative staphylococci but both cause systemic symptoms. Inguinal infections usually cause localized swelling often with a sinus tract, bleeding or distal embolism. Aortic infections commonly present with abdominal discomfort retroperitoneal infection or a mass from a false aneurysm. Stent infections usually cause pain, swelling, erythema and circulation disturbances of the ipsilateral limb. The most useful investigations are blood cultures and computerized tomography or magnetic resonance imaging. These imaging techniques have a high sensitivity and specificity in advanced graft infections but these are considerably lower in low-grade infections. Persistence of perigraft fluid beyond 3 months after surgery is suspicious of infection. Aggressive antimicrobial therapy is an important part of management but surgery is usually required to cure both graft and stent infections. Where the organisms are susceptible, high-dose beta-lactam therapy (e.g. flucloxacillin, dicloxacillin or a first-generation cephalosporin) plus low-dose gentamicin are recommended initially. Some authorities add rifampicin after 3-5 days treatment, but this is controversial. Antimicrobial therapy can be stopped 4-6 weeks after surgery if arterial stump cultures are negative but should be continued long-term, and perhaps indefinitely, if they are positive.

Reduced Vancomycin Susceptibility inStaphylococcus aureus, Including Vancomycin-Intermediate and Heterogeneous Vancomycin-Intermediate Strains: Resistance Mechanisms, Laboratory Detection, and Clinical Implications

“…Alexander Ogston first isolated Staphylococcus aureus from a surgical abscess in 1880 and described the role of S. aureus in localized infection and septicemia, including the use of animal models of infection (233,325). Staphylococcus aureus is recognized as a cause of a wide range of infections, from minor skin infections and chronic bone infections to devastating septicemia and endocarditis (44,45,48,63,99,124,179,207,218,277,(308)(309)(310)(311). The history of S. aureus is one of evolution and change.…”

Rising incidence of Staphylococcus aureus with reduced susceptibility to vancomycin and susceptibility to antibiotics: a global analysis 2004–2009

“…Staphylococcus aureus is widely recognised as the causative pathogen of various infections, ranging from infections of the skin and soft tissues such as muscle, fat and chronic bone infections, to septicaemia and endocarditis for which various therapies including tigecycline are available [1][2][3][4][5]. Significant events in the evolution of S. aureus have included the development of hospital-associated meticillin resistance, the recent emergence of community strains of S. aureus that are meticillin-resistant and the emergence of isolates that express intermediate resistance or full resistance to vancomycin [6].…”

Abdominal aortic pseudoaneurysm caused by prolonged methicillin-resistant Staphylococcus aureus sepsis

“…If we suspect pseudoaneurysm with infection, multi-slice CT may be a useful tool in detecting unexpected lesion in a non-invasive manner [3,4]. In fact, CT angiography was very helpful in detecting the pseudoaneurysm and we should further use multi-slice CT.…”