Abstract: Methods and compositions for detecting an antibiotic-inactivating factor produced by a microorganism are described herein.

Abstract: Methods and compositions for detecting an antibiotic-inactivating factor produced by a microorganism are described herein.

Abstract: A method for determining whether a microorganism produces an AmpC ?-lactamase is disclosed in which a culture of a microorganism suspected of producing a ?-lactamase that inactivates a ?-lactam-containing antibiotic is admixed with an effective amount of each of i) a ?-lactam-containing antibiotic, ii) a ?-lactamase inhibitor to which AmpC ?-lactamase is resistant, and iii) a permeabilizing agent for the microorganism present in a non-growth-inhibiting microorganism-permeabilizing amount to form an assay culture. That assay culture in maintained under appropriate culture conditions and for a time period sufficient to determine the interaction of the microorganism with the AmpC ?-lactamase resistant inhibitor and antibacterial compound, and thereby determine the presence of an AmpC ?-lactamase, wherein a positive test indicates the presence of an AmpC ?-lactamase.

Abstract: A method for determining whether a microorganism produces an AmpC ?-lactamase is disclosed in which a culture of a microorganism suspected of producing a ?-lactamase that inactivates a ?-lactam-containing antibiotic is admixed with an effective amount of each of i) a ?-lactam-containing antibiotic, ii) a ?-lactamase inhibitor to which AmpC ?-lactamase is resistant, and iii) a permeabilizing agent for the microorganism present in a non-growth-inhibiting microorganism-permeabilizing amount to form an assay culture. That assay culture in maintained under appropriate culture conditions and for a time period sufficient to determine the interaction of the microorganism with the AmpC ?-lactamase resistant inhibitor and antibacterial compound, and thereby determine the presence of an AmpC ?-lactamase, wherein a positive test indicates the presence of an AmpC ?-lactamase.

Abstract: The present invention provides a method of determining the antibiotic susceptibility of a microorganism comprising the following steps. First, a culture of the microorganism whose susceptibility is to be determined is admixed with an antibiotic to which susceptibility is to be assayed, and a permeabilizing agent for the microorganism present in a non-growth-inhibiting microorganism-permeabilizing effective amount to form an assay culture. Next, the assay culture is incubated under appropriate culture conditions and for a time sufficient to determine the susceptibility of the microorganism to the antibiotic.

Abstract: The present invention provides a method of determining the antibiotic susceptibility of a microorganism comprising the following steps. First, a culture of the microorganism whose susceptibility is to be determined is admixed with an antibiotic to which susceptibility is to be assayed, and a permeabilizing agent for the microorganism present in a non-growth-inhibiting microorganism-permeabilizing effective amount to form an assay culture. Next, the assay culture is incubated under appropriate culture conditions and for a time sufficient to determine the susceptibility of the microorganism to the antibiotic.

Abstract: An apparatus for performing 3-dimensional antibiotic susceptibility tests includes a plate with culture medium thereon, the plate rotatably mounted to a support for selective rotation. A knife is located to cut a slit in the culture medium as the plate is rotated, with a dispensing stylus located to dispense inoculum into the slit formed by the knife. A wedge apparatus is mounted adjacent the plate with a wedge-shaped leg depending into the culture medium so as to compress the culture medium towards the center of the plate, to thereby force the walls of the slit together after the inoculum has been deposited within the slit. A method for performing modified 3-dimensional antibiotic susceptibility tests includes the step of uniformly spreading a test microorganism over the top surface of culture medium on a plate. A slit is then formed in the culture medium and a uniform stream of suspending medium with a test microorganism therein is dispensed in and along the length of the slit.