Acknowledgement: We are grateful to MD Burcin Sener, of Hacettepe University Medical Faculty, Department of Medical Microbiology, Ankara, Turkey, for providing plasmid-mediated AmpC beta-lactamase
positive control isolates.
Carbapenem resistance and acquired class D beta-lactamases
in Acinetobacter baumannii from Croatia 2009-2010.
Class A, and D beta-lactamases
all share a serine residue in the active site, while class B enzymes require the presence of zinc for activity (and hence are referred to as metallo-beta-lactamases).
(11,12) Extended-spectrum beta-lactamase
producers were primerly isolated from the female medical ward (20.2%), male surgical ward (17.7%), and male medical ward and female surgical ward (13.4%) and ICU (12.3%).
However, on genotypic detection, beta-lactamases
were observed in 15.6% (n=5), 6.2% (n=2), 3.1% (n=1) and 28.1% (n=9) isolates showing presence of [bla.sub.CTX-M], [bla.sub.TEM], [bla.sub.SHV] and [bla.sub.ampC] genes, respectively.
Emergence of extended-spectrum beta-lactamase
(ESBL)-producing Klebsiella pneumoniae in Danish hospitals; this is in part explained by spread of two CTX-M-15 clones with multilocus sequence types 15 and 16 in Zealand.
(4,5) The production of some MDR enzymes such as extendedspectrum beta-lactamases
(ESBLs) by gram-negative bacteria can be masked by the coexpression of AmpC in the same organism.
The ratio of extended spectrum beta-lactamase
production and antibiotic resistance in Escherichia coli and Klebsiella pneumoniae.
Duo et al., "DHA-1 plasmid-mediated AmpC beta-lactamase
expression and regulation of Klebsiella pnuemoniae isolates," Molecular Medicine Reports, vol.
Results were interpreted according to the guidelines of Clinical and Laboratory Standards Institute (CLSI), where interpretive criteria for ESBL activity were based on an increase of more than 5 mm in the diameter of the inhibition zone around disks containing clavulanic acid as compared to the diameters of the inhibition zone around disks free of this beta-lactamase
Boronic acid can be used as AmpC beta-lactamase
inhibitor.4 Multidrug resistance can be avoided by the restricted use of third-generation cephalosporins in neonatal sepsis.6
Phenotypic detection of extended-spectrum beta-lactamase
production in Enterobacteriaceae: review and bench guide.