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Maida CM, Milici ME, Trovato L, Oliveri S, Amodio E, Spreghini E, Scalise G, Barchiesi F. Evaluation of the disk diffusion method compared to the microdilution method in susceptibility testing of anidulafungin against filamentous fungi. J Clin Microbiol 2008; 46:4071-4. [PMID: 18923014 PMCID: PMC2593298 DOI: 10.1128/jcm.01088-08] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 07/25/2008] [Accepted: 10/02/2008] [Indexed: 11/20/2022] Open
Abstract
Susceptibility testing of anidulafungin (AFG) against 32 mold isolates showed an excellent correlation between disk diffusion (DD) and broth microdilution methods. Based on our data, a 2-microg disk of AFG and a 24-h reading time might represent the best parameters for AFG DD testing against filamentous fungi.
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Affiliation(s)
- Carmelo Massimo Maida
- Istituto di Malattie Infettive e Medicina Pubblica, Università Politecnica delle Marche, Azienda Ospedaliera-Universitaria, Ospedali Riuniti, Torrette di Ancona, Ancona, Italy
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Belakhov VV, Shenin YD. Synthesis and antifungal activity of N-trialkylsilyl derivatives of nystatin. Pharm Chem J 2008. [DOI: 10.1007/s11094-008-0117-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Clancy CJ, Yu VL, Morris AJ, Snydman DR, Nguyen MH. Fluconazole MIC and the fluconazole dose/MIC ratio correlate with therapeutic response among patients with candidemia. Antimicrob Agents Chemother 2005; 49:3171-7. [PMID: 16048920 PMCID: PMC1196236 DOI: 10.1128/aac.49.8.3171-3177.2005] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Revised: 03/24/2005] [Accepted: 04/30/2005] [Indexed: 11/20/2022] Open
Abstract
We tested 32 Candida isolates recovered in the early 1990s from the bloodstreams of patients with candidemia for in vitro susceptibility to fluconazole and determined if MIC and/or the daily dose of fluconazole/MIC ratio correlated with the response to therapy. This is a unique data set since 87.5% (28/32) of patients were treated with fluconazole doses now considered to be inadequate (=200 mg), which contributed to high therapeutic failure rates (53% [17/32]). The geometric mean MIC and dose/MIC ratio for isolates associated with therapeutic failure (11.55 mug/ml and 14.3, respectively) differed significantly from values associated with therapeutic success (0.95 mug/ml and 219.36 [P = 0.0009 and 0.0004, respectively]). The therapeutic success rates among patients infected with susceptible (MIC = 8 mug/ml), susceptible-dose dependent (S-DD) (MIC = 16 or 32 mug/ml), and resistant (MIC >/= 64 mug/ml) isolates were 67% (14/21), 20% (1/5), and 0% (0/6), respectively. A dose/MIC ratio >50 was associated with a success rate of 74% (14/19), compared to 8% (1/13) for a dose/MIC ratio =50 (P = 0.0003). Our data suggest that both fluconazole MIC and dose/MIC ratio correlate with the therapeutic response to fluconazole among patients with candidemia. In clinical practice, dose/MIC ratio might prove easier to interpret than breakpoint MICs, since it quantitates the effects of increasing fluconazole doses that are alluded to in the S-DD designation.
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Affiliation(s)
- Cornelius J Clancy
- University of Florida College of Medicine, P.O. Box 100277, JHMHC, Gainesville, FL 32610, USA.
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Ezzet F, Wexler D, Courtney R, Krishna G, Lim J, Laughlin M. Oral Bioavailability of Posaconazole in Fasted Healthy Subjects. Clin Pharmacokinet 2005; 44:211-20. [PMID: 15656699 DOI: 10.2165/00003088-200544020-00006] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND AND OBJECTIVE Posaconazole is a potent, extended-spectrum triazole antifungal agent currently in clinical development for the treatment of invasive fungal infections. This study was conducted to compare the bioavailability and resulting serum concentrations of posaconazole 800 mg following administration of three different dose regimens to fasting adults. STUDY DESIGN This was a randomised, open-label, three-way crossover study. METHODS Subjects fasted 12 hours before and 48 hours after the administration of posaconazole oral suspension (800 mg) given as a single dose (regimen A), 400 mg every 12 hours (regimen B) or 200 mg every 6 hours (regimen C). Plasma posaconazole concentrations were determined for 48 hours after the initial dose and subjects completed a 1-week washout period between treatment regimens. A one-compartment oral model with first-order rate of absorption and first-order rate of elimination was fitted to the plasma concentration-time data. Differences in exposure were investigated by allowing the bioavailability fraction to vary among regimens. STUDY PARTICIPANTS A total of 18 healthy men were enrolled in and completed the study. MAIN OUTCOME MEASURES AND RESULTS Posaconazole relative bioavailability was estimated to be significantly different among regimens (p < 0.0001) and increased with the number of doses, such that regimen B/regimen A = 1.98 +/- 0.35, representing a 98% increase, and regimen C/regimen A = 3.20 +/- 0.69, or a 220% increase. With use of the one-compartment model, the population steady-state values for area under the concentration-time curve over 24 hours were predicted to be 3900, 7700 and 12 400 microg.h/L, with average plasma concentrations of 162, 320 and 517 microg/L for regimens A, B and C, respectively. CONCLUSION These data suggest that divided daily dose administration (every 12 or 6 hours) significantly increases posaconazole exposure under fasted conditions.
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Affiliation(s)
- Farkad Ezzet
- Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA
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Wexler D, Courtney R, Richards W, Banfield C, Lim J, Laughlin M. Effect of posaconazole on cytochrome P450 enzymes: a randomized, open-label, two-way crossover study. Eur J Pharm Sci 2004; 21:645-53. [PMID: 15066665 DOI: 10.1016/j.ejps.2004.01.005] [Citation(s) in RCA: 156] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2003] [Revised: 12/30/2003] [Accepted: 01/09/2004] [Indexed: 10/26/2022]
Abstract
Posaconazole is an antifungal with a wide-spectrum of activity against common and emerging fungal pathogens. In this randomised, open-label, two-way crossover study, the potential for drug interactions with posaconazole via the cytochrome P450 (CYP450) enzyme pathway was evaluated. Thirteen subjects received posaconazole tablets (2 x 100 mg) once daily for 10 days or no treatment; following a 14-day washout period, subjects were crossed over to the alternate treatment. The inhibition spectra of posaconazole were examined using a cocktail of the following probe substrates: caffeine (CYP1A2), tolbutamide (CYP2C8/9), dextromethorphan (CYP2D6 and total CYP3A4), chlorzoxazone (CYP2E1), and midazolam (hepatic CYP3A4). Except for midazolam, which was intravenously infused on Day 10, the cocktail probes were administered simultaneously on Day 9 during both treatment periods. Blood and urine samples were collected at specified times to quantitate probe substrates and/or metabolites. Based on insignificant differences in mean probe ratios, posaconazole did not inhibit CYP1A2, 2C8/9, 2D6, or 2E1. However, the midazolam AUC((tf)) was higher in the posaconazole than no-treatment group (93.4 n gh/ml versus 51.4 ng h/ml, P<0.01), indicating inhibition of hepatic CYP3A4. Drug interactions mediated by various CYP450 are common with the currently available triazole antifungals, however these results suggest that posaconazole may have an improved and more narrow drug interaction profile (CYP3A4 only) compared with other triazoles.
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Affiliation(s)
- D Wexler
- Schering-Plough Research Institute, K-15-2650, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA.
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Abstract
Caspofungin is the first approved agent from a new class of antifungals, the echinocandins. By targeting the fungal cell wall (as opposed to the fungal cell membrane), the echinocandins exhibit a unique mechanism of action relative to the other currently approved antifungal agents. Preclinical (in vitro and in vivo) studies have demonstrated activity for caspofungin against the most commonly encountered fungi in the hospital setting, namely Candida and Aspergillus species. Caspofungin is administered as a once-a-day, intravenous formulation. Notably, caspofungin is neither an inhibitor, inducer, nor metabolite of the cytochrome p450 system. To date, few drug-drug interactions have been seen for this echinocandin. A number of Phase II and III clinical studies in documented invasive candidiasis, esophageal candidiasis, and invasive aspergillosis have been completed and have demonstrated efficacy for caspofungin against all three diseases. In all studies, caspofungin manifested an excellent safety profile with few serious, drug-related adverse events or discontinuations due to drug-related adverse events. Isolated symptoms compatible with histamine release have been infrequently reported. In clinical studies, drug-related nephrotoxicity with caspofungin has been rare, and the incidence of liver transaminase elevations has been similar to the incidence seen with comparator agents. Results from a Phase III study as empirical therapy in patients with febrile neutropenia are anticipated in late 2003. Overall, caspofungin represents an important addition to the current antifungal armamentarium.
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Affiliation(s)
- Nicholas A Kartsonis
- Merck Research Laboratories, BL 3-4, P.O. Box 4, West Point, PA 19486-0004, USA.
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Ostrosky-Zeichner L, Marr KA, Rex JH, Cohen SH. Amphotericin B: time for a new "gold standard". Clin Infect Dis 2003; 37:415-25. [PMID: 12884167 DOI: 10.1086/376634] [Citation(s) in RCA: 260] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2003] [Accepted: 04/18/2003] [Indexed: 11/03/2022] Open
Abstract
When introduced in 1959, amphotericin B deoxycholate (AmBD) was clearly a life-saving drug. Randomized studies demonstrating its efficacy were not thought to be necessary, and it was granted indications for many invasive fungal infections. Despite its formidable toxicities, AmBD is thus often used as the primary comparator in studies of invasive fungal infections. Safer lipid-based versions of amphotericin B (AmB) have been introduced, but difficulties with studying these agents generally led to licensure for salvage therapy, not primary therapy. However, the cumulative clinical experience to date with the lipid-based preparations is now adequate to demonstrate that these agents are no less active than AmBD, and, for some infections, it can now be stated that specific lipid-based preparations of AmB are superior to AmBD. Given their superior safety profiles, these preparations can now be considered suitable replacements for AmBD for primary therapy for many invasive fungal infections in clinical practice and research.
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Affiliation(s)
- Luis Ostrosky-Zeichner
- Division of Infectious Diseases, Department of Internal Medicine, Center for the Study of Emerging and Reemerging Pathogens, University of Texas Medical School, Houston, TX, USA.
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Polak A. Antifungal therapy--state of the art at the beginning of the 21st century. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2003; Spec No:59-190. [PMID: 12675476 DOI: 10.1007/978-3-0348-7974-3_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The most relevant information on the present state of the art of antifungal chemotherapy is reviewed in this chapter. For dermatomycoses a variety of topical antifungals are available, and safe and efficacious systemic treatment, especially with the fungicidal drug terbinafine, is possible. The duration of treatment can be drastically reduced. Substantial progress in the armamentarium of drugs for invasive fungal infections has been made, and a new class of antifungals, echinocandins, is now in clinical use. The following drugs in oral and/or intravenous formulations are available: the broad spectrum polyene amphotericin B with its new "clothes"; the sterol biosynthesis inhibitors fluconazole, itraconazole, and voriconazole; the glucan synthase inhibitor caspofungin; and the combination partner flucytosine. New therapy schedules have been studied; combination therapy has found a significant place in the treatment of severely compromised patients, and the field of prevention and empiric therapy is fast moving. Guidelines exist nowadays for the treatment of various fungal diseases and maintenance therapy. New approaches interfering with host defenses or pathogenicity of fungal cells are being investigated, and molecular biologists are looking for new targets studying the genomics of pathogenic fungi.
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Regueiro-Ren A, Carroll TM, Chen Y, Matson JA, Huang S, Mazzucco CE, Stickle TM, Vyas DM, Balasubramanian BN. Core-modified sordaricin derivatives: synthesis and antifungal activity. Bioorg Med Chem Lett 2002; 12:3403-5. [PMID: 12419371 DOI: 10.1016/s0960-894x(02)00764-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Core-modified sordaricin derivatives were prepared via biotransformation followed by chemical modification and tested for antifungal activity. The antifungal activity proved to be very sensitive to modifications in the sterics and/or lipophilicity of the diterpene skeleton. Introduction of polar groups such as hydroxyl in the diterpene core results in loss of potency while small and lipophilic groups such as fluorine and the 7,8-olefin are well tolerated.
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Affiliation(s)
- Alicia Regueiro-Ren
- Bristol-Myers Squibb Pharmaceutical Research Institute, Wallingford, CT 06492, USA.
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Abstract
PURPOSE OF REVIEW An increase in refractory invasive fungal infections in the setting of marrow/solid organ transplantation and other immune-compromising clinical entities has provided the impetus for the development of new, more efficacious/less toxic antifungal agents. This review (1) examines currently available laboratory methods for the in-vitro evaluation of these new agents against both yeasts and filamentous fungi; (2) provides a summary of the most attractive investigational agents currently undergoing clinical trials/development; and (3) outlines the major refractory mycoses in contemporary medicine. RECENT FINDINGS Fluconazole-resistant Candida spp., Trichosporon spp., zygomycetous genera, the endemic mycoses, Scedosporium, Aspergillus, and Fusarium spp., and an ever-expanding list of lesser-known hyaline and phaeoid genera inciting invasive fungal infections comprise the bulk of refractory mycoses in the immune-compromised host. In-vitro data generated from reference-based antifungal susceptibility testing methods indicate an increased armamentarium of potentially efficacious agents against most of these mycoses. SUMMARY The newly approved antifungal agents caspofungin and voriconazole, used either as monotherapy or in combination regimens, have a significantly improved spectrum of activity over previously available therapeutic options. Correlation of clinical outcomes with investigational agents demonstrating in-vivo/in-vitro activity will provide critical information needed for the development of clinically significant minimum inhibitory concentration interpretative breakpoints.
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Affiliation(s)
- Deanna A Sutton
- Fungus Testing Laboratory, Department of Pathology, Unversity of Texas Halth Science Center at San Antonio, Texas 78229-3900, USA.
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Arikan S, Paetznick V, Rex JH. Comparative evaluation of disk diffusion with microdilution assay in susceptibility testing of caspofungin against Aspergillus and Fusarium isolates. Antimicrob Agents Chemother 2002; 46:3084-7. [PMID: 12183278 PMCID: PMC127447 DOI: 10.1128/aac.46.9.3084-3087.2002] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2001] [Revised: 03/25/2002] [Accepted: 06/05/2002] [Indexed: 11/20/2022] Open
Abstract
We compared the disk diffusion and broth microdilution methods for susceptibility testing of caspofungin against Aspergillus (n = 78) and Fusarium (n = 22) isolates. Microdilution testing followed the NCCLS M-38P guidelines but was performed in antibiotic medium 3 supplemented to 2% glucose (AM3). Disk diffusion assays were performed on AM3 agar plates with a 2- micro g caspofungin disk. By both methods, caspofungin showed favorable activity against Aspergillus isolates and no activity against Fusarium isolates. In the disk-based format, intrazonal growth that was not influenced by the drug concentration gradient was consistently observed for all of the Aspergillus isolates tested.
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Affiliation(s)
- Sevtap Arikan
- Division of Infectious Diseases, Department of Internal Medicine, Center for the Study of Emerging and Reemerging Pathogens, University of Texas Medical School, Houston, Texas 77030, USA.
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Iwen PC, Hinrichs SH, Rupp ME. Utilization of the internal transcribed spacer regions as molecular targets to detect and identify human fungal pathogens. Med Mycol 2002; 40:87-109. [PMID: 11860017 DOI: 10.1080/mmy.40.1.87.109] [Citation(s) in RCA: 204] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Advances in molecular technology show great potential for the rapid detection and identification of fungi for medical, scientific and commercial purposes. Numerous targets within the fungal genome have been evaluated, with much of the current work using sequence areas within the ribosomal DNA (rDNA) gene complex. This section of the genome includes the 18S, 5.8S and 28S genes which code for ribosomal RNA (rRNA) and which have a relatively conserved nucleotide sequence among fungi. It also includes the variable DNA sequence areas of the intervening internal transcribed spacer (ITS) regions called ITS1 and ITS2. Although not translated into proteins, the ITS coding regions have a critical role in the development of functional rRNA, with sequence variations among species showing promise as signature regions for molecular assays. This review of the current literature was conducted to evaluate clinical approaches for using the fungal ITS regions as molecular targets. Multiple applications using the fungal ITS sequences are summarized here including those for culture identification, phylogenetic research, direct detection from clinical specimens or the environment, and molecular typing for epidemiological investigations. The breadth of applications shows that ITS regions have great potential as targets in molecular-based assays for the characterization and identification of fungi. Development of rapid and accurate amplification-based ITS assays to diagnose invasive fungal infections could potentially impact care and improve outcome for affected patients.
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Affiliation(s)
- P C Iwen
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha 68198-6495, USA.
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Rex JH, Pfaller MA, Walsh TJ, Chaturvedi V, Espinel-Ingroff A, Ghannoum MA, Gosey LL, Odds FC, Rinaldi MG, Sheehan DJ, Warnock DW. Antifungal susceptibility testing: practical aspects and current challenges. Clin Microbiol Rev 2001; 14:643-58, table of contents. [PMID: 11585779 PMCID: PMC88997 DOI: 10.1128/cmr.14.4.643-658.2001] [Citation(s) in RCA: 278] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Development of standardized antifungal susceptibility testing methods has been the focus of intensive research for the last 15 years. Reference methods for yeasts (NCCLS M27-A) and molds (M38-P) are now available. The development of these methods provides researchers not only with standardized methods for testing but also with an understanding of the variables that affect interlaboratory reproducibility. With this knowledge, we have now moved into the phase of (i) demonstrating the clinical value (or lack thereof) of standardized methods, (ii) developing modifications to these reference methods that address specific problems, and (iii) developing reliable commercial test kits. Clinically relevant testing is now available for selected fungi and drugs: Candida spp. against fluconazole, itraconazole, flucytosine, and (perhaps) amphotericin B; Cryptococcus neoformans against (perhaps) fluconazole and amphotericin B; and Aspergillus spp. against (perhaps) itraconazole. Expanding the range of useful testing procedures is the current focus of research in this area.
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Affiliation(s)
- J H Rex
- Division of Infectious Diseases, Department of Internal Medicine, Center for the Study of Emerging and Reemerging Pathogens, University of Texas Medical School, Houston, Texas 77030, USA.
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Rex JH, Sobel JD. Prophylactic antifungal therapy in the intensive care unit. Clin Infect Dis 2001; 32:1191-200. [PMID: 11283809 DOI: 10.1086/319763] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2000] [Revised: 11/29/2000] [Indexed: 11/03/2022] Open
Abstract
Antifungal prophylaxis is regularly used during treatment of patients with some cancers, as subgroups with high rates of invasive fungal infections are readily identified; for these patients, prophylaxis has been shown to be of value. High-risk liver transplant recipients also benefit from antifungal prophylaxis. Although the idea of extending this concept to the prevention of candidal infections in the larger population of critically ill patients who are seen in the intensive care unit (ICU) and who do not have neutropenia is attractive, implementation of this strategy is difficult because of the widely varying characteristics of patients in the ICU. Two studies have shown the benefit of such prophylaxis, but the benefit was shown only in selected groups of patients who had an unusually high risk for invasive candidiasis. Although the concept is sound, broad-scale implementation of antifungal prophylaxis would be premature and costly, both financially and with regard to resistance and toxicity. Investigations are needed to define and prove the utility of predictive tools for the identification of patients in the ICU who would benefit from prophylaxis.
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Affiliation(s)
- J H Rex
- Division of Infectious Diseases, Department of Internal Medicine, Center for the Study of Emerging and Re-Emerging Pathogens, University of Texas Medical School, Houston, TX 77030, USA.
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