James W. Myers

Prosthetic joint infection by Mycobacterium tuberculosis : An unusual case report with literature review

Prosthetic joint infection with Mycobacterium tuberculosis usually involves the hips or knees and can result from either local reactivation, or less often from hematogenous spread. Predisposing conditions include rheumatoid arthritis, chronic steroid use and pulmonary diseases. The most common symptom at presentation is pain, and the most common physical finding is joint swelling and/or a draining sinus tract. The sedimentation rate is helpful when elevated but is nonspecific, and initial skin testing is only helpful when positive. The diagnosis depends on culture and histologic examination of tissue. Removal of the joint combined with oral antituberculous treatment is necessary when the infection is discovered greater than six weeks post joint replacement. Early diagnosis leads to decreased morbidity. Tuberculous infection of prosthetic joints is a rare disease and its diagnosis depends on a high degree of clinical suspicion.

Prosthetic Device Infections

Fortunately, infection is a rare complication of prosthetic devices. Despite the presence of infection, removal of these devices is not always possible or necessary. The introduction of foreign material enhances the pathogenicity of known pathogens and increases the potential of less virulent microorganisms to cause damage. Thus, Staphylococcus epidermidis is a very common organism in patients with prosthetic devices as compared with the normal healthy population. Fibronectin promotes adherence of staphylococci to chronically implanted devices. An extracellular substance called “glycocalyx” has been associated with coagulase-negative staphylococci including S. epidermidis. A polysaccharide “adhesin” facilitates adherence of staphylococci to foreign material and functions as an antiphagocytic capsule. The function of polymorphonuclear leukocytes is also impaired in the presence of foreign bodies. There is deficient superoxide production, which leads to impaired killing of microorganisms. Also, recent data suggest a role for small colony variants (SCV) of staphylococci that may cause persistent and recurrent infections as a result of their capacity to survive within, but not lyse, whole cells. When these bacteria adhere to foreign bodies, they undergo dramatic metabolic changes such as slower growth, decreased metabolism, and enhanced resistance to antibiotics. These organisms can be difficult to detect in the microbiology laboratory and also difficult to treat with conventional antibiotics (1).

An Elderly Man with Immunosuppression, Shortness of Breath, and Eosinophilia

post splenectomy complained that he had had shortness of breath since receiving a diagnosis of chronic lymphocytic leukemia in 1998. He had documented eosinophilia since 1999 that was attributed to his leukemia. He presented with a 2week history of worsening shortness of breath, cough productive of brown sputum, intermittent fevers and chills, mild night sweats, and poor appetite. He denied having diarrhea, abdominal pain, or recent travel and has lived in eastern Tennessee his entire life. Medications he was receiving included weekly rituxan for chronic lymphocytic leukemia, which had been added recently to his treatment regimen, as well as long-term steroid therapy. Physical examination revealed an elderly man who was afebrile and tachpneic (24 breaths/min). Oral ex-

Lactic acidosis during nucleoside antiretroviral HIV therapy

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Lack of inhibition of sodium polyanethol sulfonate (SPS) on recovery of Moraxella (Branhamella) catarrhalis from blood cultures

Abstract Moraxella (Branhamella) catarrhalis , although commonly isolated from sputum in patients with pneumonia, rarely causes bacteremia. Sodium polyanethol sulfonate is commonly added to routine blood culture media to increase the yield of Gram-negative bacilli. This anticoagulant also inhibits the growth of Neisseria meningitidis . We added strains f Moraxella (Branhamella) catarrhalis to routine blood culture media supplemented with 0.03% SPS. No inhibitory effect could be demonstrated. The rare occurrence of bacteremic Moraxella (Branhamella) catarrhalis pneumonia is not due to an inhibitory effect of routine blood culture media.