ISOLATION OF β-LACTAM RESISTANT ENTEROBACTERIA

• Published in: Journal of The Showa Medical Association Vol. 63; no. 3; pp. 265 - 272
• Main Authors: CHEN, Gelin, WAKUTA, Rika, NAKASHIMA, Osamu, MIYAMOTO, Akitoshi, FUKUCHI, Kunihiko
• Format: Journal Article
• Language: Japanese
• Published: The Showa University Society 28.06.2003
• Subjects: ESBLs : extended-spectrum β-lactamases; metallo-β-lactamases; MIC: minimum inhibitory concentration; Pulsed-field gel electrophoresis
• ISSN: 0037-4342; 2185-0976
• DOI: 10.14930/jsma1939.63.265

We analyzed the isolation of enterobacteria at Showa University Hospital in 2001 and compared the site of isolation and its antibiotic resistance with data of 1991-1992 or 1997-1998. The identification and antibiotic susceptibility tests were performed by Microscan Walk Away (Dade Behring, USA) . Escherichia coli and Klebsiella pneumoniae were most frequently isolated. Although the number of Escherichia coli isolates from the respiratory tract increased, the susceptibility pattern was similar to that of 1991-1992. As for Klebsiella pneumoniae and Klebsiella oxytoca, the sites of isolation and the susceptibility patterns were similar to those of 1997-1998. It should be noted that 23 strains of ESBL-producing Escherichia coli, 19 strains of ESBL-producing Klebsiella pneumoniae and 4 strains of ESBL-producing Klebsiella oxytoca were isolated. A total of 399 strains of Serratia marcescens were isolated. The ratio of met allo-β-lactamase-producing Serratia marcescens was 3% in 1997-1998. In this survey, 42 strains of imipenem resistant Serratia marcescens, which is considered to be metallo-β-lactam ase producing Serratia marcescens, were isolated; this accounted for 10% of the Serratia marcescens. Analysis of the genome digestion pattern using pulsed field gel electrophoresis revealed that 30 of the 42 strains of imipenem-resistant Serratia marcescens were identical, indicating an outbreak. After containment of the outbreak, the ratio of imipenem-resistant Serratia marcescens decreased to 3%. We also isolated Enterobacter cloacae and Enterobacter aerogenes 417 and 144 strains, respectively; both bacteria were resistant to ampicillin, cefazolin, and cefmetazole. The most alarming finding of the present survey is the emergence of ESBL-producing bacteria.