AmpC β -lactamase producedby Klebsiella pneumoniae is required to be diagnosed differentially with Klebsiella pneumoniae Carbapenemase

Abstract

AmpC β-lactamase-producing bacteria have emerged worldwide. It is important to detect plasmid-mediated AmpC β-lactamase-producing bacteria, which can spread to other organisms, for surveillance and hospital infection control. Here, we report the case of infection by Klebsiella pneumoniae producing AmpC β-lactamase, which is required for differential diagnosis of infection by Klebsiella pneumoniae producing carbapenemase. A 62-year-old male with pulmonary abscess was referred to our hospital with the chief complaint of hemoptysis in August, 2012. The use of an automated bacterial culture system led to the isolation of carbapenemase-producing K. pneumoniae from the sputum of this patient. The Hodge test, Cica-Beta-Test I, and double disc synergy test with sodium mercaptoacetic acid showed negative results. The samples were sent to National Institute for Infectious Diseases, Japan. After the boronic acid test, the isolate was identified as K. pneumoniae producing DHA-type AmpC β-lactamase. Genetic knowledge and skills are required for the diagnosis and detection of drug-resistant bacteria and accurate diagnosis.