scholarly journals Establishment of In Vitro Susceptibility Testing Methodologies and Comparative Activities of Piperacillin in Combination with the Penem β-Lactamase Inhibitor BLI-489

2008 ◽  
Vol 53 (2) ◽  
pp. 370-384 ◽  
Author(s):  
Peter J. Petersen ◽  
C. Hal Jones ◽  
Aranapakam M. Venkatesan ◽  
Tarek S. Mansour ◽  
Steven J. Projan ◽  
...  

ABSTRACT The novel bicyclic penem inhibitor BLI-489 has demonstrated activity as an inhibitor of class A, C, and D β-lactamases. To determine the combination of piperacillin and BLI-489 to be used in susceptibility testing that would most accurately identify susceptible and resistant isolates, a predictor panel of β-lactamase-producing bacteria was utilized to determine the reliability of the combination of piperacillin-BLI-489 at a constant inhibitor concentration of 2 or 4 μg/ml and at ratios of 1:1, 2:1, 4:1, and 8:1. There were a number of strains that would be falsely reported as susceptible or intermediate if tested with the ratios of 1:1 and 2:1, whereas the constant concentration of 2 μg/ml of BLI-489 and the ratio of 8:1 had a tendency to overpredict resistance. Similar MICs were obtained with piperacillin-BLI-489 in a 4:1 ratio and when BLI-489 was held constant at 4 μg/ml. Based on these results, an in vitro testing methodology employing a constant concentration of 4 μg/ml BLI-489 was used to evaluate the combination of piperacillin-BLI-489 against a larger panel of recently identified clinical isolates. Approximately 55% of all of the enteric bacilli tested were nonsusceptible to piperacillin alone (MIC ≥ 32 μg/ml). However, 92% of these piperacillin nonsusceptible strains were inhibited by ≤16 μg/ml piperacillin-BLI-489; in contrast, only 66% were inhibited by ≤16 μg/ml piperacillin-tazobactam. The combination of piperacillin-BLI-489 also demonstrated improved activity compared to that of piperacillin-tazobactam against the problematic extended-spectrum β-lactamase- and AmpC-expressing strains.

2018 ◽  
Vol 6 ◽  
pp. 2050313X1880407 ◽  
Author(s):  
Michael Sander ◽  
Judith L Isaac-Renton ◽  
Megan A Sander

We report a case of cutaneous Mycobacterium marinum infection with the unusual reported features of pruritus and paresthesia. In addition, we report a lack of in-vivo response to antibiotics based on in-vitro susceptibility testing.


1998 ◽  
Vol 42 (2) ◽  
pp. 471-472 ◽  
Author(s):  
M. Hong Nguyen ◽  
Christine Y. Yu

ABSTRACT In vitro susceptibility testing for 50 clinical isolates of fluconazole-susceptible or -resistant Cryptococcus neoformans was performed with itraconazole and voriconazole. Voriconazole was more potent than itraconazole for fluconazole-susceptible isolates and as potent as itraconazole for fluconazole-susceptible dose-dependent isolates and for fluconazole-resistant isolates. For fluconazole-resistant isolates, the voriconazole and itraconazole MICs ranged from 1 to 2 μg/ml.


1999 ◽  
Vol 12 (1) ◽  
pp. 40-79 ◽  
Author(s):  
Daniel J. Sheehan ◽  
Christopher A. Hitchcock ◽  
Carol M. Sibley

SUMMARY Major developments in research into the azole class of antifungal agents during the 1990s have provided expanded options for the treatment of many opportunistic and endemic fungal infections. Fluconazole and itraconazole have proved to be safer than both amphotericin B and ketoconazole. Despite these advances, serious fungal infections remain difficult to treat, and resistance to the available drugs is emerging. This review describes present and future uses of the currently available azole antifungal agents in the treatment of systemic and superficial fungal infections and provides a brief overview of the current status of in vitro susceptibility testing and the growing problem of clinical resistance to the azoles. Use of the currently available azoles in combination with other antifungal agents with different mechanisms of action is likely to provide enhanced efficacy. Detailed information on some of the second-generation triazoles being developed to provide extended coverage of opportunistic, endemic, and emerging fungal pathogens, as well as those in which resistance to older agents is becoming problematic, is provided.


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