Agostino Maiello

Glycopeptide Bone Penetration in Patients with Septic Pseudoarthrosis of the Tibia

Background and objective: In the treatment of bone infections, a major determinant of the clinical response is the active drug concentration at the infected site. Because of the high prevalence of meticillin (methicillin)-resistant staphylococci and enterococci, glycopeptides are widely used for the treatment of bone and joint infections, but data on their penetration into human bone are lacking. The aim of our study was to measure vancomycin and teicoplanin concentrations in infected human bone under steady-state conditions and verify their relationship with inflammatory markers, patient demographic characteristics and pharmacodynamic microbiological markers.Methods and patients: Twenty-seven adult orthopaedic patients undergoing surgical debridement for septic pseudoarthrosis of the tibia and receiving either intravenous vancomycin (Vancocina® 1 g twice daily) or teicoplanin (Targosid® 10 mg/kg/day) were studied from January 2004 to January 2008. Plasma and bone specimens were simultaneously collected during surgery for pharmacokinetic and microbiological assays at a variable interval after antimicrobial administration. Bone samples were dissected into cortical and cancellous bone, cleaned of soft tissues, crushed and eluted into phosphate buffer. Necrotic samples and sequestra were not analysed.Plasma and bone antimicrobial concentrations were measured by a validated method of high-performance liquid chromatography with UV detection, and bone/plasma concentration ratios were calculated. Cortical and cancellous bone area under the concentration-time curve (AUC) over 24 hours (AUC24) values were measured by the linear-log trapezoidal rule, using WinNonlin® software, and were compared with the minimum inhibitory concentrations (MICs) of the infecting agents.Results: For vancomycin, the mean ± SD concentrations were 2.66 ± 1.2 mg/L in cortical bone and 11.53 ± 7.8 mg/L in cancellous bone (corresponding to 20.67% and 89.39% of intraoperative plasma concentrations), and the mean ± SD tissue AUC24 values were 55.15 ± 25.26 h · mg/L for cortical bone and 299.16 ± 299.54 h · mg/L for cancellous bone. For teicoplanin, the mean ± SD concentrations were 2.01 ± 1.7 and 7.51 ± 7.0 mg/L in cortical and cancellous bone, respectively (12.35% and 48.6% of intraoperative plasma concentrations), and the mean ± SD teicoplanin tissue AUC24 values were 34.08 ± 23.6 h · mg/L and 155.17 ± 132.8 h · mg/L for cortical bone and cancellous bone, respectively. The mean vancomycin AUC24/MIC ratios were 215.02 for plasma, 47.14 for cortical bone and 268.95 for cancellous bone. The mean teicoplanin AUC24/MIC ratios were 336.48, 36.27 and 197.21 for plasma, cortical bone and cancellous bone, respectively.Conclusions: Bone penetration of both glycopeptides ranged from poor (<15%) to satisfactory (15–30%) in the cortical compartment, while it was far higher into the highly vascularized cancellous tissue. Vancomycin bone penetration was slightly higher than with teicoplanin, but the difference was not statistically significant. Higher bone concentrations were observed with higher inflammatory markers, possibly as a result of increased vascularization and vascular permeability under inflammatory conditions. Bone concentrations over the MIC and AUC/MIC ratios suggested that both glycopeptides achieve a satisfactory pharmacokinetic exposure in the cancellous bone, as far as Gram-positive pathogens are concerned. On the other hand, cortical bone exposure was suboptimal in most patients. Furthermore, as antimicrobial penetration may be affected by impaired blood supply, the role of radical surgical removal of purulent and necrotic tissues appears to be essential in order to shorten treatment duration and to reduce the risk of treatment failure.

The Influence of Cytomegalovirus on the Natural History of HIV Infection: Evidence of rapid course of HIV infection in HIV-positive patients infected with Cytomegalovirus

We studied a cohort of 299 HIV-positive individuals with known date of seroconversion to evaluate the role of Cytomegalovirus (CMV) in the natural history of HIV. The study population consisted of 236 initially CMV-positive patients, 55 CMV-negative subjects and 8 CMV seroconverters. The study endpoints were the decline to CD4+ < 200 x 10(6) cells/l, AIDS, and death. The cumulative risk of CMV disease and the survival after CMV disease were also investigated. At intake, there was no inter-group difference in sex, age, risk behaviours, history of hairy leucoplakia or herpes zoster and antiretroviral treatment. During the follow-up, 108 patients fell below 200 CD4+ x 10(6) cells/l, 72 developed AIDS and 63 died. Twenty-one subjects had CMV disease. The cumulative incidence of CMV disease in the cohort was 18.9%, and 23.3% within 8 and 9 years for the initially CMV-positive patients and 33.3% and 66.7% for the CMV seroconverters (log-rank test: p = 0.101). The median survival after CMV disease was 153 days (range: 28-855, interquartile range: 261), with a cumulative survival of 45.1%, 16.9% and 4.3% within 6, 12 and 18 months, respectively. On Coxs regression, the acute HIV seroconversion was an independent predictor of each endpoint, history of hairy leucoplakia or herpes zoster being associated only with CD4+ cell decline. Baseline CMV seropositivity was related to short survival (p = 0.037) and 2 x 2 inter-group comparison showed that older individuals with sexually acquired HIV who seroconverted to CMV had higher rates of progression to the study endpoints. Our data suggest that CMV infection influences the natural history of HIV disease and that CMV disease strongly affects the survival of the HIV-positive patients.

Osteomyelitis Caused by Enterobacter cancerogenus Infection following a Traumatic Injury: Case Report and Review of the Literature

ABSTRACT We report a case of osteomyelitis caused by Enterobacter cancerogenus resistant to aminopenicillins in a 56-year-old male who had a motorcycle accident and suffered from multiple bone fractures with abundant environmental exposure. E. cancerogenus has rarely been associated with human infections, and its clinical significance remains unclear.

Ceftriaxone bone penetration in patients with septic non-union of the tibia

OBJECTIVES A main determinant of clinical response to antibiotic treatment is drug concentration at the infected site. Data on ceftriaxone (CFX) bone penetration are lacking. We measured CFX concentrations in infected bone to verify their relationship with pharmacodynamic microbiological markers. METHODS Eleven patients undergoing debridement for septic non-union of the tibia and receiving intravenous CFX were studied. Plasma and bone specimens were collected intraoperatively at a variable interval after CFX administration. Drug concentrations were measured by high-performance liquid chromatography with ultraviolet detection (HPLC-UV) method. RESULTS Bone samples were extracted at a mean of 3.3 h (range 1.5-8.0 h) since the start of CFX infusion. The mean±standard deviation intraoperative CFX plasma concentration was 128.4±30.8 mg/l; the corresponding bone concentrations were 9.6±3.4 mg/l (7.8%) in the cortical compartment and 30.8±8.6 mg/l (24.3%) in the cancellous compartment. The mean 24-h area under the concentration-time curve (AUC(24)) values were 176.8±62.2 h*mg/l in cortical bone and 461.5±106.8 h*mg/l in cancellous bone. The time above the minimum inhibitory concentration (T>MIC) was 24 h in all compartments. The estimated mean free AUC/MIC ratios and T>MIC were 140 and 24.4 h, respectively, in cancellous bone and 42.4 and 21 h, respectively, in cortical bone. CONCLUSIONS CFX bone penetration was poor (<15%) in the cortical compartment and satisfactory in the more vascularized cancellous bone. The T>MIC and AUC/MIC ratios suggest that CFX achieves a satisfactory pharmacokinetic exposure in cancellous bone as far as pathogens with a MIC of <0.5 are concerned. However, considering free drug concentrations, pharmacokinetic/pharmacodynamic targets may not be fully achieved in cortical bone. As antibiotic exposure can be suboptimal in the infected cortical compartment, and drug penetration may be impaired into necrotic bone and sequesters, a radical surgical removal of purulent and necrotic tissues appears essential to shorten treatment duration and to prevent treatment failures.

Cryoglobulinemia-Related Vasculitis During Effective Anti-HCV Treatment with PEG-Interferon alfa-2b

HCV infection may be related to many extrahepatic manifestations including mixed cryoglobulinemia (MC). Clinical manifestations commonly associated to MC include arthralgia, purpura, vasculitis, peripheral neuropathy and renal function abnormalities. Treatment with interferon often leads to remission, especially in virological responders, or to disappearance of MC-related clinical manifestations. We report on a patient with chronic hepatitis C, deficit of G6P-DH, type II MC, who developed a cryoglobulinemic vasculitis with purpura, renal impairment and arterial hypertension, during treatment with PEG-interferon a-2b plus amantadine. The occurrence of purpuric lesions and MC-related nephropathy with increased cryocrit despite negative viremia, in a patient previously asymptomatic, during interferon treatment, is unusual.

Post-Traumatic Osteomyelitis Due to Aspergillus flavus Successfully Treated with Voriconazole: A Case Report

We describe a case of a 69-year-old diabetic man who developed an extensive osteomyelitis of the tibia due to Aspergillus flavus, more than 20 after a car accident. In addition to radical surgical debridément, the infection was successfully managed with a 7-month course of voriconazole. A 69-year-old diabetic man was admitted to our hospital in February 2006 for chronic osteomyelitis of the left tibia with acute necrotizing fasciitis of surrounding soft tissues (Figure 1). In 1969 the patient had had a severe car accident with an open and ground-contaminated fracture of both the left tibia and fibula. Thereafter he underwent multiple surgeries, including a bone transplant for non-healing of the fracture and persistent leg pain. Twenty years later the patient was diagnosed with diabetes mellitus and was treated with oral hypoglycemic agents. In spite of good metabolic control and the absence of an evident peripheral vasculopathy, since August 2005 he gradually developed a wide necrotic ulcer on the tibial face of his right leg, with edema, sero-purulent drainage and progressive exposure of the underlying bone. X-ray showed extensive bone reabsorption with osteolytic areas, consistent with chronic osteomyelitis of the tibia. A 3-month course of broad-spectrum antibiotics, including meropenem and vancomycin, was ineffective and in February 2006 the patient underwent surgical debridément with sequestrectomy and removal of necrotic tissue, followed by application of a bone graft. A subsequent histological examination of bone specimens yielded the presence of fungi with septate hyphae and cultures grew Aspergillus flavus. Laboratory tests showed a persistent mild eosinophilia (8.2%, 429 cells/mm3) with increased erythrocyte sedimentation rate (ESR =134 mm at first hour) and C-reactive protein (CRP = 12 mg/dl). Intravenous antifungal therapy, consisting of voriconazole 4 mg/Kg b.i.d. (loading dose of 6 mg/Kg b.i.d. the first day), was immediately started and then switched to the oral formulation one month later. The clinical picture was further complicated by a polymicrobial bacterial superinfection of the ulcer that led to a necrotizing fasciitis of the leg and required fasciotomy plus a 4-week course of intravenous antibiotic therapy with teicoplanin and meropenem. Three months later, while on continuing antifungal therapy, another surgical intervention of debridément and bone filling with lyophilized bone chips was performed; cultures of tissue biopsy and bone specimen were negative.

Lopinavir Measurement in Pleural Effusion in a Human Immunodeficiency Virus Type 1-Infected Patient with Kaposi's Sarcoma

Human immunodeficiency virus type 1 (HIV-1) infection is highly compartmentalized within various organs. Tissue dissemination is evident in the lung ([1][1]), the male ([3][2]) and female ([8][3]) genital tracts, the lymph nodes ([12][4]), and especially in the brain ([5][5], [12][4]). This process