Detection of Plasmid-Mediated AmpC b-Lactamases

Although plasmid-mediated AmpC b-lactamases were first reported in the late 1980's, most clinical laboratories and physicians remain unaware of their clinical importance. Current detection methods for organisms producing plasmid-mediated AmpC b-lactamases are time-consuming and technically-demanding for clinical laboratories to perform on a routine basis. Multiplex PCR is also available as a research tool for the detection of this resistance mechanism but is not yet available for routine use. Because of the lack of PCR and the difficulty of current detection methods, organisms producing these types of b-lactamases often go undetected and have therefore been responsible for nosocomial and community outbreaks. The detection of organisms producing these b-lactamases is thus important for infection control and to ensure effective therapeutic options. Currently, there are no recommendations available from the National Committee for Clinical Laboratory Standards (NCCLS) for detection of organisms producing plasmid-mediated AmpC b-lactamases. Therefore, clinical laboratories need an inexpensive and convenient method to detect this resistance mechanism. Because of this need, two new methods for detection of plasmid-mediated AmpC b-lactamases were developed and investigated in this research. The first method was based on a reagent disk test that utilizes a filter paper disk impregnated with a permeabilizing agent to detect plasmid-mediated AmpC b-lactamases. The second method was based on the diagnostic utility of the AmpC b-lactamase inhibitors 48-1220 (Ro 48-1220) and LN-2-128 for detection of organisms producing plasmid-mediated AmpC b-lactamases using methodology similar to the NCCLS guidelines for ESBL confirmation disk test. In this research, the reagent disk test method proved to be a very sensitive, specific, and convenient method for detection of plasmid-mediated AmpC b- lactamases in organisms lacking a chromosomal AmpC b-lactamase. The AmpC b- lactamase inhibitor disk test method also proved to be simple to perform and easy to interpret having clear-cut guidelines for interpretation. Both methods developed in this research showed potential and should be further investigated.

Grantor dc:publisher

Creighton University

Year dc:date.issued

2004

Author dc:creator

• Black, Jennifer A.

Advisor dc:contributor.advisor

• Thomson, Kenneth S.

Statement dc:rights

• Copyright is retained by the Author. A non-exclusive distribution right is granted to Creighton University and to ProQuest following the publishing model selected above.

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10504/68463

OAI identifier oai:identifier

oai:cdr.creighton.edu:10504/68463