Wide occurrence of plasmid-mediated AmpC b-lactamase-producing Escherichia coli, Klebsiella spp., Proteus mirabilis, and Salmonella spp. isolates in Korea: results of a multicentre survey in 2007

Abstract number: P1223

Song W., Kim J.S., Lee H., Jeong S.H., Uh Y., Hong S.G., Lee K., Woo G.J.

Objectives: Plasmid-mediated AmpC b-lactamases (PABLs) are cephalosporinases that confer resistance to a wide variety of b-lactam drugs and that may thereby create serious therapeutic problems. The PABL-producing organisms are a major concern in nosocomial infections and should therefore be monitored in surveillance studies. The present study was conducted to determine the epidemiology and genotypic distributions of PABL-producing isolates in Korea.

Methods: During the period of May to August 2007, a total of 1,350 consecutive and nonrepeat isolates of Escherichia coli, Klebsiella spp., Proteus mirabilis, and Salmonella spp. were collected at 12 hospitals in Korea. The 248 (18.4%) cefoxitin non-susceptible isolates tested for multiplex AmpC PCR and DNA sequencing. The PABL-positive isolates were further investigated for antimicrobial susceptibility by broth microdilution methodology and extended-spectrum b-lactamases (ESBLs) by boronic acid disk tests.

Results: PABL producers were found at all the 12 sites in Korea. PABLs were found in 15/577 E. coli (2.6%; 9 of DHA-like, 5 of CMY-like, and 1 of ACT-1-like); 152/544 K. pneumoniae (27.9%; 149 of DHA-like, 1 of CMY-like, and 2 of ACT-1-like); 6/65 K. oxytoca (9.2%; 6 of DHA-like); 3/104 P. mirabilis (2.9%; 1 of DHA-like and 2 of CMY-like); and 1/60 Salmonella spp. (1.7%; 1 of CMY-like) isolates. One hundred and four of the 152 PABL-producing K. pneumoniae isolates (68.4%) coproduced ESBLs. Susceptibilities of the PABL-producing K. pneumoniae were as follows: ceftazidime, 3%; cefotaxime, 26%; aztreonam, 26%; cefepime, 79%; imipenem, 99%; gentamicin, 12%; amikacin, 14%; and ciprofloxacin, 11%.

Conclusion: PABL producers were found to be widespread in Korea. A DHA type is the most prevalent enzyme and the DHA-producing K. pneumoniae isolates have rapidly increased in Korea. Each of the PABLs is associated with multidrug resistance. Clinical laboratories should be able to detect PABLs to ensure optimal patient care and infection control.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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