Daptomycin is a cyclic lipopeptide antibiotic that has been available in the United States since September 2003. We report a clinical and bacteriological failure of daptomycin therapy for enterococcal bacteremia. Briefly, a 22-year-old man with Hodgkin's lymphoma, subsequent acute myelogenous leukemia, and nonseminomatous testicular carcinoma developed neutropenic fever during chemotherapy in 2004. A urine culture at hospital admission yielded 50,000 to 100,000 CFU of Enterococcus faecium/ml that were resistant to vancomycin (VRE) but susceptible to daptomycin (MIC ϭ 2 g/ml) and doxycycline. The patient initially received doxycycline, cefepime, metronidazole, and vancomycin. Two days later, a urine culture grew Ͻ10,000 CFU of VRE/ml. Computed tomography of the abdomen revealed bilateral wedge-shaped renal hypodensities compatible with a diagnosis of focal pyelonephritis. All blood cultures obtained during early hospitalization were negative, and on hospital day (HD) 8 the patient's urine culture was negative. Due to persistent fever, daptomycin (6 mg/kg of body weight/day) was used in place of doxycycline and vancomycin beginning on HD 9 and continuing until HD 26, for 17 days of therapy. When chemotherapy was again initiated, the fever returned, and blood cultures at that time grew Escherichia coli, for which meropenem was initiated. The patient continued to be febrile, and a blood culture revealed VRE. Susceptibility testing performed by the broth microdilution method with calcium-supplemented Mueller-Hinton broth and by the disk diffusion procedure (5, 6) indicated a daptomycin MIC of greater than 32 g/ml and a reduced disk diffusion zone diameter (Table 1). While the daptomycin MIC reflected resistance, the zone of inhibition was within the range indicative of susceptibility (i.e., Ն11 mm) by the recently published breakpoints (3). Daptomycin was discontinued and linezolid was initiated at 600 mg intravenously twice daily. The fever persisted, and daptomycin-resistant VRE again grew from two blood cultures obtained 5 days after linezolid was initiated. Linezolid was continued with the addition of doxycycline, and the catheter was removed. The fever abated, and all further blood cultures were negative. Pulsed-field gel electrophoresis of SmaI digests of chromosomal DNA of the four VRE isolates indicated that they were highly related.Daptomycin is a new agent for treating serious methicillinresistant Staphylococcus aureus (MRSA) and enterococcal infections (1, 2). Its value has been due in part to the fact that resistance of MRSA and VRE to linezolid has already been encountered, and quinupristin-dalfopristin resistance of VRE has been widely reported (7,8,9). A previous examination of a collection of unrelated VRE from several geographic areas of the United States did not reveal any isolates with daptomycin MICs that exceeded 8 g/ml (4). This appears to represent the first description of a clinical and bacteriological failure of an invasive VRE infection due to the emergence of high-level daptomycin resistanc...

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The promising data that have emerged in the last year indicate that we may have six available drugs to treat resistant S. aureus infections within the next few years. The next goal is to determine the appropriate indications and cost-effectiveness of each of these drugs in our treatment strategy against S. aureus and other Gram-positive pathogens.

Moraxella lacunata is a rare, usually commensal gram-negative rod most commonly associated with eye infections. We report a unique case of noniatrogenic M. lacunata bacteremia and septic knee arthritis in a patient with class III-IV lupus nephritis and speculate on the association between invasive Moraxella infection and renal impairment. CASE REPORTOn 5 December 2008, a 24-year-old woman with lupus nephritis presented at her routine nephrology appointment with a 1-week history of increasing edema, arthralgia, and intermittent fevers. One week prior, she had been discharged from a referring institution on a prednisone taper for an acute lupus flare. She was taking 60 mg of prednisone per day with 500 mg of mycophenolate mofetil (CellCept; self-initiated) twice per day at the time of her nephrology appointment. Examination revealed severe lower-extremity pitting edema, swollen knees, and a tender, swollen right wrist. Movement of her left knee induced severe pain.At baseline, the patient's biopsy-proven class III-IV lupus nephritis was associated with mild joint swelling and minimal periorbital edema, typically responsive to corticosteroids and immunosuppressive therapy. Given her recent history of highdose steroid and immunosuppressant usage, investigation into a source of her worsening renal dysfunction separate from her underlying lupus nephritis was warranted.Laboratory studies indicated leukocytosis (white blood cell count, 24 ϫ 10 3 /l [normal range, 3.6 ϫ 10 3 to 11.0 ϫ 10 3 /l]) and acute renal failure requiring emergent hemodialysis (potassium level, 6.8 meq/liter [normal range, 3.5 to 5.1 meq/liter]; blood urea nitrogen level, 200 mg/dl [normal range, 7 to 25 mg/dl]; and creatinine level, 4.2 mg/dl [normal range, 0.7 to 1.6 mg/dl]). Fecal cultures were unrevealing, urine cultures revealed 50,000 to 100,00 CFU/ml of Citrobacter koseri, and two of two blood cultures grew Moraxella lacunata (Table 1). She remained febrile with persistent M. lacunata growth in two of two blood cultures on the second day of admission, despite therapy every 6 h with 2.25 g of intravenous piperacillin-tazobactam, chosen for its broad-spectrum coverage of gram-negative rods including pseudomonas. Further studies to evaluate the source of her persistent bacteremia were performed; an echocardiogram showed a small pericardial effusion with no evidence of endocarditis, and bilateral knee arthrocentesis revealed M. lacunata growth from left knee synovial fluid (Table 2).Following septic knee debridement, she clinically improved with 10 days of intravenous piperacillin-tazobactam and progressive advancement in her activities of daily living. She remained afebrile until discharge. Surveillance blood and synovial fluid cultures on the third day of admission revealed no further bacterial growth. She continued to improve with eventual resolution of her renal failure.This case highlights the invasive potential of M. lacunata and emphasizes the importance of searching for occult sources of infection, particularly in an immunocompromised ho...

This study assessed an erythromycin-clindamycin (ERY-CC) broth test for inducible CC resistance in beta-hemolytic streptococci. One hundred one isolates of groups A, B, C, F, and G were tested by the CLSI broth microdilution method. Combinations of 1 and 0.25 g/ml or 0.5 and 0.25 g/ml of ERY and CC, respectively, detected all inducible isolates.