Lack of value of repeat stool testing for Clostridium difficile toxin.

Twenty years ago, Clostridium difficile was first established as a cause of pseudomembranous colitis and antibiotic-associated diarrhea.C. difficile diarrhea is a widely recognized problem in the inpatient setting, with potentially significant morbidity and mortality. Antibiotics, and some chemotherapy agents, can potentially cause C. difficile colitis/diarrhea. The most commonly implicated agents are ampicillin, clindamycin, and cephalosporins. Diarrhea during antibiotic therapy is common and may be caused by C. difficile. Testing for C. difficile differentiates diarrheas into C. difficile positive and C. difficile negative. C. difficile can be carried asymptomatically as normal gastrointestinal flora, and in adults who have received antibiotic therapy, carrier states can be as high as 46%. Hospitalized patients are often colonized with C. difficile. C. difficile produces 3 virulence factors: an enterotoxin (toxin A), a cytotoxin (toxin B), and a substance to inhibit bowel motility. Different tests can be used to detect these toxins. The most widely used test is the enzyme immunoassay (EIA) for toxin A, toxin B, or both. The EIA C. difficile toxin assay has sensitivity and specificity ranges of 50% to 90% and 70% to 95%, respectively. Diagnostically, C. difficile cell culture cytotoxin assay remains the gold standard with sensitivity and specificity of 93% and 89%, respectively. Because of lack of confidence of the EIA for C. difficile, some clinicians assume an initial negative result may represent a false-negative test, and repeat testing is often done. We evaluated the value of repeat stool testing for C. difficile toxin A and B by EIA in inpatients with nosocomial diarrhea on antibiotics.

Fever of unknown origin: chronic lymphatic leukemia versus lymphoma (Richter's transformation).

Currently, malignancies are more common than infections as a cause of fever of unknown origin (FUO) in adults. Many malignant disorders are associated with fever, which may either be of the hectic-septic variety resembling an infectious disease or prolonged and low-grade. Neoplasms with either kind of fever may present as an FUO. The malignancies usually associated with fever are lymphoreticular malignancies involving the blood, liver, spleen, or bone marrow. Most malignancies do not have fever, e.g., chronic lymphatic leukemia (CLL), as part of their clinical presentation. We present a case of long-standing CLL in an elderly woman who presented with an FUO. Initially, it was thought that her FUO was caused by CLL or a CLL-related opportunistic infection. The naprosyn test was used in this patient with CLL and FUO to differentiate a malignant from an infectious etiology. Her response to naprosyn indicated that the etiology of her FUO was neoplastic rather than infectious. The absence of tonsillar enlargement and peripheral adenopathy, as well as the presence of fever, argued against CLL as the cause of her fever. Computed axial tomography scans showed central adenopathy in addition to splenomegaly. The presence of fever, splenomegaly, and central adenopathy indicated that the cause of her FUO was a lymphoma (Richter's transformation) and not CLL.

Daptomycin cure after cefazolin treatment failure of Methicillin-sensitive Staphylococcus aureus (MSSA) tricuspid valve acute bacterial endocarditis from a peripherally inserted central catheter (PICC) line.

Right-sided acute bacterial endocarditis (ABE) is an infrequent complication of central intravenous (IV) lines. We report a case of methicillin-sensitive Staphylococcus aureus tricuspid valve (TV) ABE related to a peripherally inserted central catheter line (PICC). Patients with right-sided ABE present with symptoms of fever and chills, and symptoms and signs of pulmonary emboli. In the patient presented, the PICC line was removed and high-dose cefazolin therapy, 2 g (IV) every 8 hours, was initiated. Although the patient's blood cultures became negative during the third week of cefazolin therapy, her erythrocyte sedimentation rate and teichoic acid antibody titers remained high. Pulmonary emboli developed. A large TV vegetation (1 x 2 cm) remained unchanged after 4 weeks of cefazolin therapy. For these reasons, cefazolin treatment was considered a treatment failure. Therapy with daptomycin was initiated at a dose of 6 mg/kg (IV) every 24 hours. During daptomycin therapy, the patient's erythrocyte sedimentation rate and teichoic acid antibody titers gradually returned to normal. Repeat transthoracic echocardiograph revealed the TV vegetation was gone and the methicillin-sensitive Staphylococcus aureus ABE was cured with daptomycin. We conclude daptomycin is a rapidly bactericidal antistaphylococcal antibiotic reliably effective even when other usually effective antistaphylococcal antibiotics have failed.