We conducted a prospective, multicenter observational study of adults (n=1447) and children (n=144) with candidemia at tertiary care centers in the United States in parallel with a candidemia treatment trial that included nonneutropenic adults. Candida albicans was the most common bloodstream isolate recovered from adults and children (45% vs. 49%) and was associated with high mortality (47% among adults vs. 29% among children). Three-month survival was better among children than among adults (76% vs. 54%; P<.001). Most children received amphotericin B as initial therapy, whereas most adults received fluconazole. In adults, Candida parapsilosis fungemia was associated with lower mortality than was non-parapsilosis candidemia (24% vs. 46%; P<.001). Mortality was similar among subjects with Candida glabrata or non-glabrata candidemia; mortality was also similar among subjects with C. glabrata candidemia who received fluconazole rather than other antifungal therapy. Subjects in the observational cohort had higher Acute Physiology and Chronic Health Evaluation II scores than did participants in the clinical trial (18.6 vs. 16.1), which suggests that the former subjects are more often excluded from therapeutic trials.

Candida bloodstream isolates (n ‫؍‬ 2,000) from two multicenter clinical trials carried out by the National Institute of Allergy and Infectious Diseases Mycoses Study Group between 1995 and 1999 were tested against amphotericin B (AMB), flucytosine (5FC), fluconazole (FLU), itraconazole (ITR), voriconazole (VOR), posaconazole (POS), caspofungin (CFG), micafungin (MFG), and anidulafungin (AFG) using the NCCLS M27-A2 microdilution method. All drugs were tested in the NCCLS-specified RPMI 1640 medium except for AMB, which was tested in antibiotic medium 3. A sample of isolates was also tested in RPMI 1640 supplemented to 2% glucose and by using the diluent polyethylene glycol (PEG) in lieu of dimethyl sulfoxide for those drugs insoluble in water. Glucose supplementation tended to elevate the MIC, whereas using PEG tended to decrease the MIC. Trailing growth occurred frequently with azoles. Isolates were generally susceptible to AMB, 5FC, and FLU. Rates of resistance to ITR approached 20%. Although no established interpretative breakpoints are available for the candins (CFG, MFG, and AFG) and the new azoles (VOR and POS), they all exhibited excellent antifungal activity, even for those strains resistant to the other aforementioned agents.

Pan-drug-resistant (PDR)Acinetobacter baumannii is an important nosocomial pathogen that poses therapeutic challenges. Tigecycline alone or in combination with agents such as colestimethate, imipenem, and/or amikacin is being used clinically to treat PDR A. baumannii infections. The purpose of this study was to compare in vitro susceptibility testing by epsilometric (Etest) methods and the checkerboard (CB) method with testing by time-kill analysis. PDR A. baumannii clinical strains representing eight unique pulsed-field gel electrophoresis clones selected from a total of 32 isolates were tested in vitro with tigecycline, colestimethate, imipenem, and amikacin in single-and two-drug combinations by using two different methods of Etest (with a fixed ratio method [method 1] and with the incorporation of the active drug in medium [method 2]) and by using CB. The three-drug combination of imipenem, tigecycline, and amikacin was also tested by CB. These results were compared to time-kill results. Synergy was consistently detected with the imipenem plus colestimethate and tigecycline plus imipenem combinations. The Etest method with active drug incorporated into the agar allowed us to detect synergy even in the presence of the active drug and was more comparable to CB and time-kill tests. Synergy was detected with the three-drug combination of imipenem, tigecycline, and amikacin by both CB and time-kill methods among several tested clones. These findings indicate the utility of synergy testing to predict activity of specific antibiotic combinations against PDR A. baumannii.In recent years Acinetobacter baumannii, an aerobic, Gramnegative coccobacillus, has emerged as an important nosocomial pathogen due to multiple drug resistance mechanisms, and it can be an extremely difficult microorganism for the clinician to treat (3,8,20,22). It causes a variety of infections that include pneumonia, wound, urinary tract, bloodstream, and intra-abdominal infections (3,8). We had experienced an increased number of cases of A. baumannii with resistant or intermediate susceptibility patterns to carbapenems over a 2-year time frame at our medical center. Growing numbers of isolates locally, nationally, and internationally have shown resistance to antibiotics such as the carbapenems, which previously had excellent activity in vitro and clinically. Our annual medical center antibiograms and a review of the literature (1,9,10,12,20,22,23,25,26) support this. Nontraditional agents, such as colestimethate (polymyxin E) and polymyxin B, despite the associated high toxicities, are being used to treat patients infected with pan-drug-resistant (PDR) A. baumannii (with pan-drug resistance defined as resistance to all routinely tested antimicrobials including carbapenems). Antibiotic resistance has also developed among some strains during treatment with these agents (10,20). Drug treatment with newer antimicrobials or antimicrobial combinations has become increasingly important to eradicate these infections.Tigecycline was approved by the Food ...

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