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Biomedical subjects

Michael G Rinaldi

Publications and source records attributed to Michael G Rinaldi.

At least 37 records · Page 2Linked to original sources
PubMed2003

Outbreak of invasive Aspergillus infection in surgical patients, associated with a contaminated air-handling system.

An outbreak of Aspergillus infection at a tertiary care hospital was identified among inpatients who had amputation wounds, peritonitis, allograft nephritis, or mediastinitis. During a 2-year period, 6 patients were identified, all of whom had Aspergillus species recovered from samples from normally sterile sites. All cases clustered in the operating theater during a single 12-day period. To assess operating theater air quality, particle counts were measured as surrogate markers for Aspergillus conidia. A substantial increase in the proportion of airborne particles > or =3 microm in size (range, 3-fold to 1000-fold) was observed in many operating rooms. A confined space video camera identified moisture and contamination of insulating material in ductwork and variable airflow volume units downstream of final filters. No additional invasive Aspergillus wound infections were identified after the operating theater air-handling systems were remediated, suggesting that this unusual outbreak was due to the deterioration of insulating material in variable airflow volume units.

Air Conditioning↗
PubMed2003

Experimental pulmonary aspergillosis due to Aspergillus terreus: pathogenesis and treatment of an emerging fungal pathogen resistant to amphotericin B.

Aspergillus terreus is an uncommon but emerging fungal pathogen, which causes lethal infections that are often refractory to amphotericin B (AmB). In comparison to Aspergillus fumigatus, A. terreus was resistant to the in vitro fungicidal effects of safely achievable concentrations of AmB. These in vitro findings correlated directly with resistance of A. terreus to AmB in experimental invasive pulmonary aspergillosis. Residual fungal pulmonary burden and galactomannan antigenemia demonstrated persistent infection, despite therapy with deoxycholate AmB or liposomal AmB. By comparison, posaconazole and itraconazole resolved GM antigenemia, reduced residual fungal burden, and improved survival. There were no differences in phagocytic host response to A. terreus versus A. fumigatus; however, the rate of conidial germination of A. terreus was slower. The strain of A. terreus with the highest minimum inhibitory and minimum lethal concentration of AmB also had the lowest membrane ergosterol content. The hyphae of A. terreus in vivo displayed distinctive aleurioconidia, which may be a practical microscopic feature for rapid preliminary diagnosis.

Amphotericin B↗
PubMed2003

In vitro activities of new antifungal agents against Chaetomium spp. and inoculum standardization.

Chaetomium is an unusual etiological agent of human infections, but the mortality rate among immunocompromised patients is considerably greater than that among nonimmunocompromised individuals. We investigated the in vitro antifungal susceptibilities to novel antifungal agents of 19 strains belonging to three species of Chaetomium which have been involved in human infections, i.e., Chaetomium globosum, C. atrobrunneum, and C. nigricolor, and one strain of the closely related species Achaetomium strumarium. A modification of the NCCLS reference microdilution method (M38-A) was used to evaluate the in vitro activities of ravuconazole, voriconazole, albaconazole, and micafungin. Micafungin was not active at all, while the geometric mean MICs and minimum effective concentrations of the three triazoles were less than 0.5 and 0.4 micro g/ml, respectively.

Antifungal Agents↗
PubMed2003

Activity of posaconazole against Pseudallescheria boydii: in vitro and in vivo assays.

Thirty isolates of Pseudallescheria boydii were tested to compare the in vitro activity of posaconazole with those of fluconazole and itraconazole, using NCCLS methods. Posaconazole was evaluated in an immunosuppressed mouse model of disseminated pseudallescheriasis. Posaconazole was more effective than itraconazole and as effective as fluconazole in preventing death and significantly reducing the CFU of P. boydii from tissues.

Animals↗
PubMed2003

Enteral fluconazole population pharmacokinetics in patients in the surgical intensive care unit.

STUDY OBJECTIVE: To determine the population pharmacokinetic parameters of enterally administered fluconazole in patients in a surgical intensive care unit (SICU). DESIGN: Population pharmacokinetics component of a prospective, randomized clinical study. SETTING: The SICU at a university hospital. PATIENTS: One hundred ten patients with an expected length of stay in the SICU of 3 or more days and a need for intubation, in whom at least one fluconazole plasma concentration-time measurement was available. Intervention. Patients received fluconazole as an 800-mg loading dose and as a 200- or 400-mg (depending on renal function) daily maintenance dose. Fluconazole suspension was administered enterally followed by a 30-ml free water flush. MEASUREMENTS AND MAIN RESULTS: Plasma samples were collected, and population pharmacokinetic analysis was performed with NONMEM software; a one-compartment pharmacokinetic model was used. Fluconazole clearance was dependent on creatinine clearance, and volume of distribution was dependent on body weight and age. In patients with creatinine clearance values greater than 80 ml/minute, between 30 and 80 ml/minute, and less than 30 ml/minute, geometric mean (percentage coefficient of variation) fluconazole clearance was 14.39 ml/minute (21%), 10.53 ml/minute (28%), and 5.47 ml/minute (30%), respectively. The geometric mean (percentage coefficient of variation) volume of distribution in all patients was 1.27 L/kg (28%) and decreased with increasing age. CONCLUSIONS: Fluconazole clearance values in patients in the SICU who had normal renal function and in those with renal impairment were in agreement with previously reported data. Fluconazole volume of distribution was larger and half-life was longer in the SICU population than in healthy subjects.

Adult↗
PubMed2003

Steady-state plasma concentrations of itraconazole after oral administration in Kemp's ridley sea turtles, Lepidochelys kempi.

Pharmacokinetic studies of antifungal agents in reptiles are uncommon. Itraconazole, which has been used prophylactically in juvenile sea turtles suffering from hypothermia (cold stunning) on a regular basis, was evaluated for steady-state plasma concentrations. Five Kemp's ridley sea turtles (Lepidochelys kempi) receiving itraconazole at several dosages in a rehabilitation program had blood collected within 24 hr to estimate dosing frequency. Subsequently, serial blood samples of Kemp's ridley sea turtles that were given itraconazole at several dosages for 30 days to treat cold stunning were collected at various intervals to evaluate itraconazole plasma concentrations. Tissue samples were collected from one Kemp's ridley that died during rehabilitation. Plasma concentrations of itraconazole (and of hydroxyitraconazole [OH-ITRA], one of its major bioactive metabolites) were determined using a modified, validated reverse-phase high-performance liquid chromatography technique. Itraconazole concentrations in tissues were determined by bioassay to be far greater than the plasma concentrations measured in any of the turtles. At a 15-mg/kg dosage, the half-life (t1/2) was 75 hr for itraconazole and 55 hr for OH-ITRA. All dosages produced adequate concentrations in some turtles, but consistent therapeutic concentrations were produced only at 15 mg/kg q72hr and 5 mg/kg s.i.d., with the latter producing the highest plasma concentrations.

Administration, Oral↗
PubMed2002

Office practice-based confirmation of onychomycosis: a US nationwide prospective survey.

BACKGROUND: Onychomycosis is sufficiently prevalent to be seen and treated by primary care physicians. The diagnosis of onychomycosis is most often confirmed from nail specimens by microscopy and fungal culture done at a central laboratory; these are relatively expensive tests with a turnaround time of a month or more. This study was conducted (1) to evaluate the use of in-office dermatophyte test medium (DTM) culture, and (2) to determine the epidemiology of onychomycosis in a large, nationwide sample of patients who were not participants in a clinical trial. METHODS: A nationwide sample of primary care physicians and podiatrists enrolled 670 patients with clinical signs of toenail onychomycosis. Dermatophyte test medium cultures were performed in the office and the results were compared with fungal cultures performed by a central laboratory. RESULTS: Central laboratory fungal cultures were positive in 44% (n = 297) of patients and DTM cultures in 51% (n = 345). Dermatophytes accounted for 93% of the confirmed infections and nondermatophyte molds the rest. In the 617 patients with paired dermatophyte test medium and laboratory fungal culture results, the 2 tests were in agreement (both positive or both negative) in 68% of cases (kappa, 0.37; asymptotic SE, 0.04; 95% confidence interval, 0.299-0.441). CONCLUSIONS: A DTM culture is a relatively rapid, easy, and inexpensive method to confirm dermatophyte infections in patients with signs of onychomycosis in the primary care setting. Because the available drugs for treating onychomycosis are effective against all dermatophyte species, the confirmation of dermatophyte infection, without further identification of genus and species, is sufficient evidence to begin treatment.

Adolescent↗
PubMed2002

Disseminated phaeohyphomycosis: review of an emerging mycosis.

Disseminated phaeohyphomycosis is an uncommon infection caused by dematiaceous fungi, although the number of case reports about this infection has been increasing in recent years. A total of 72 cases are reviewed. Scedosporium prolificans is by far the most common cause. The presence of melanin in their cell walls may be a virulence factor for these fungi. The primary risk factor is decreased host immunity, although cases in apparently immunocompetent patients have been reported. Eosinophilia was seen in 11% of cases. Endocarditis is mostly reported on bioprosthetic valves, particularly those of porcine origin. The outcome of antifungal therapy remains poor, with an overall mortality rate of 79%. Special precautions taken for immunocompromised patients may help prevent exposure to fungi during the patients' period of greatest risk. The development of newer antifungal agents and combination therapy may hold promise in improving the management of these devastating infections in the future.

Adolescent↗
PubMed2002

Zygomycosis.

Zygomycosis, an uncommon but frequently fatal mycosis caused by fungi of the class Zygomycetes, develops most commonly as an opportunistic disease. Successful therapy involves a combined approach based on early diagnosis, prompt institution of medical therapy, and extensive surgical debridement of all devitalized tissue. Given the rarity of this condition, novel therapeutic strategies have been limited and only tested on an individual basis. The use of high-dose lipid formulations of amphotericin B, prompt reversal of the underlying predisposing condition, and hyperbaric oxygen are the most common strategies that have shown potential value in the treatment of zygomycosis.

Antifungal Agents↗
PubMed2002

Enteral fluconazole is well absorbed in critically ill surgical patients.

BACKGROUND: Enteral fluconazole, a triazole antifungal agent with an excellent oral bioavailability, has not been widely studied in critically ill surgical patients. METHODS: During a randomized placebo-controlled trial of enteral fluconazole (N = 130) versus placebo (N = 130) for the prevention of fungal infections in critically ill surgical patients, trough fluconazole levels were measured after the loading dose and 3 times weekly during intensive care unit stay. Minimum inhibitory concentrations (MICs) for fluconazole were measured on all infecting Candida isolates. RESULTS: Four hundred sixty-seven serum samples were assayed for fluconazole levels in 121 patients. The most common infecting fungal species was Candida albicans, isolated in 14 of 31 infections (45%). Other infecting species were C glabrata, C tropicalis, and C parapsilosis. Mean fluconazole levels were above the highest MIC for C albicans and C parapsilosis in all but 5 patients (4%). Mean fluconazole levels were below the median MIC for C glabrata in 93 of 121 patients (77%). No significant relationship was seen between fluconazole levels and risk for fungal infection. CONCLUSIONS: Serum fluconazole levels are above the MIC of most yeast species found in these patients. These levels may not be above the MIC of C glabrata, the second most common Candida isolate causing infection in this study.

Absorption↗
PubMed2002

Pseudallescheria boydii (Anamorph Scedosporium apiospermum). Infection in solid organ transplant recipients in a tertiary medical center and review of the literature.

(Sca) is a ubiquitous filamentous fungus capable of causing invasive disease. We reviewed our electronic microbiology records and the English-language literature. Between 1976 and December 1999 we identified 23 solid organ transplant recipients with Sca infection, 7 of which occurred between December 1987 and December 1999 at our institution. Overall incidence was 1 per 1,000 patients, with a trend of higher incidence in patients receiving lung transplants compared with other transplant organs (p = 0.06). The 23 patients included liver (4), kidney (8), heart (8), lung (2), and heart/lung (1) recipients. Male to female ratio was 19:4, and the mean age was 46 +/- 12 (SD) years. Fungal infection was diagnosed at a median of 4 months (range, 0.4-156 mo) after transplant. The clinical presentation included disseminated disease ( 8), skin lesions (3), lung disease (5), endophthalmitis (1), meningitis (1), brain abscess with or without extension to eye (3), fungal mycotic aneurysm (1), and sinusitis (1). Seven (30%) patients had intravascular infection, and 11 (48%) patients had central nervous system involvement. Antifungal therapy was accompanied by surgical debridement in 9 cases. Three additional patients were found to have airway colonization only and received itraconazole prophylaxis, without evidence of disease. Of 22 patients with known outcome, 16 (72.7%) died. Five of 6 patients who survived had localized infections: skin lesions (n = 3), sinus fungus ball (n = 1), and solitary lung nodule (n = 1). All patients with disseminated disease and 10 of 11 patients with central nervous system disease died. An exception was 1 patient with a brain abscess, successfully treated with voriconazole and surgical drainage. Sca infection is rare but is associated with high mortality. Early diagnosis by culture is important because Sca is resistant to amphotericin B, routinely used in the empiric therapy of invasive fungal infections. Treatment with the combination of an antifungal and surgery may have a better outcome. Voriconazole promises to be an effective antifungal agent. Cultures positive for Sca should not be ignored, and long-term antifungal prophylaxis in candidates and transplant recipients should be considered.

Adult↗
PubMed2002

In vitro activities of posaconazole, itraconazole, voriconazole, amphotericin B, and fluconazole against 37 clinical isolates of zygomycetes.

In vitro antifungal susceptibility testing results of a new antifungal triazole, posaconazole (POS), were compared to results with amphotericin B (AMB), itraconazole (ITC), voriconazole (VRC), and fluconazole (FLC) against clinical agents of zygomycosis. The MICs of POS at which 50% and 90% of the isolates were inhibited were 0.25 and 4 microg/ml, respectively. POS was significantly more active than VRC and FLC and slightly more active than ITC. The results suggest that POS has significant potential for clinical development against the zygomycetes.

Amphotericin B↗
PubMed2002

In vitro activities of free and lipid formulations of amphotericin B and nystatin against clinical isolates of Coccidioides immitis at various saprobic stages.

We investigated the susceptibilities of hyphal, mixed hyphal, ungerminated arthroconidial, and germinated arthroconidial populations of Coccidioides immitis to lipid formulations of amphotericin B and nystatin and their conventional preparations, utilizing the National Committee for Clinical Laboratory Standards M38-P broth macrodilution method. The differences in effects of the three different growth stages of the saprobic phase of C. immitis on the MIC/minimum lethal concentration (MLC) ratio were not statistically significant for any of the antifungal agents tested. These results suggest that either inocula could be used for in vitro susceptibility studies with C. immitis.

Amphotericin B↗
PubMed2002

In vitro interaction of caspofungin acetate with voriconazole against clinical isolates of Aspergillus spp.

The interaction between caspofungin acetate and voriconazole was studied in vitro by using 48 clinical Aspergillus spp. isolates obtained from patients with invasive aspergillosis. MICs were determined by the NCCLS broth microdilution method. Synergy, defined as a fractional inhibitory concentration (FIC) index of <1, was detected in 87.5% of the interactions; an additive effect, defined as an FIC index of 1.0, was observed in 4.2% of the interactions; and a subadditive effect, defined as an FIC index of 1.0 to 2.0, was found in 8.3% of the interactions. No antagonism was observed. Animal models are required to validate the in vivo significance of these in vitro data presented for the combination of caspofungin and voriconazole.

Anti-Bacterial Agents↗
PubMed2002

Disseminated mycotic infection caused by Colletotrichum acutatum in a Kemp's ridley sea turtle (Lepidochelys kempi).

Colletotrichum acutatum is a cosmopolitan plant pathogen with a wide host range. While the organism's phytopathogenic potential has been well documented, it has never been reported as an etiologic agent of disease in either animals or humans. In this case, a juvenile Kemp's ridley sea turtle, Lepidochelys kempi, probably with immune compromise following cold stunning (extended hypothermia), developed a disseminated mycotic infection in the lungs and kidneys. Prophylactic treatment with oral itraconazole did not prevent or cure the infection. This report of a Colletotrichum acutatum infection in an animal extends the range of disease caused by this organism beyond that of a phytopathogen.

Animals↗
PubMed2002

In vitro activities of terbinafine in combination with fluconazole, itraconazole, voriconazole, and posaconazole against clinical isolates of Candida glabrata with decreased susceptibility to azoles.

A checkerboard microdilution method, performed according to the recommendations of the National Committee for Clinical Laboratory Standards, was used to study the in vitro interaction of terbinafine (TRB) with fluconazole (FLU), itraconazole (ITRA), voriconazole (VRC), and posaconazole (PSZ) in 24 isolates of Candida glabrata with decreased susceptibility to azoles isolated from the oral cavities of human immunodeficiency virus patients. Synergy, defined as a fractional inhibitory concentration index of < or =0.5, was observed in 17% of TRB-FLU interactions, 21% of TRB-ITRA interactions, 33% of TRB-VRC interactions, and 12% of TRB-PSZ interactions. Where synergy was not achieved, there was still a decrease in the MIC of one or both drugs when used in combination. Antagonism was not observed in any drug combination. Clinical studies are warranted to elucidate the potential utility of these combination therapies.

Antifungal Agents↗