Detection of plasmid-mediated AmpC beta-lactamase in Escherichia coli and Klebsiella pneumoniae


YILMAZ N. O., AGUS N., Bozcal E., Oner O., UZEL A.

INDIAN JOURNAL OF MEDICAL MICROBIOLOGY, vol.31, no.1, pp.53-59, 2013 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 31 Issue: 1
  • Publication Date: 2013
  • Doi Number: 10.4103/0255-0857.108723
  • Journal Name: INDIAN JOURNAL OF MEDICAL MICROBIOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.53-59
  • Keywords: AmpC beta-lactamase, boronic acid, extended spectrum beta-lactamases, pulsed-field gel electrophoresis, IDENTIFICATION, INFECTIONS, RESISTANCE, SPP.
  • Istanbul University Affiliated: No

Abstract

Background: Detecting plasmid-mediated AmpC (pAmpC). beta-lactamase-producing organism is important for optimal infection control and providing accurate and effective treatment option for physicians. Objectives: The aim of this study was to investigate the prevalence of pAmpC. beta-lactamase and compare the results of boronic acid (BA) disk test with other phenotypic tests detecting AmpC positive isolates. Materials and Methods: A total of 273 clinical isolates of Klebsiella pneumoniae (n: 82) and Escherichia coli (n: 191) were analysed. The presence of pAmpC. beta-lactamase was determined by BA disk test, cefoxitin (FOX) screening test, modified three dimensional test (M3DT), and multiplex polymerase chain reaction (PCR). Pulsed-field gel electrophoresis was performed to evaluate the genetic similarities between isolates. To detect extended spectrum. beta-lactamases (ESBL) in the presence of AmpC. beta-lactamase, ESBL confirmation test was carried out with and without BA solution. Results: Of the 273 strains tested, 127 strains were found FOX resistant, 114 were positive by M3DT, 108 were positive in BA disk test, and the multiplex PCR detected 24 pAmpC. beta-lactamase-positive isolate. The prevalence of AmpC-producing strains was 10.9% in E. coli and 3.6% in K. pneumoniae in the tested population by PCR. CIT and MOX group genes were predominant type in these strains. Conclusion: These results emphasize that clinical laboratories should consider testing the presence of pAmpC enzymes particularly in FOX-resistant isolates, and BA disk test will improve detection of this emerging resistance phenotype.