Background & objectives: Members of the family enterobacteriaceae comprise the most common gram-negative isolates in microbiology laboratories. Amongst these members, multiple antibiotic-resistant isolates including those producing extended spectrum β-lactamases (ESBL) and AmpC β-lactamases (AmpC) have increased steadily. Further, metallo-β-lactamase (MBL) producing strains are also recently de...

The current phenotypic methods for detecting carbapenemase-producing Enterobacteriaceae (CPE) allow differentiation between class A and B carbapenemases, but they cannot confirm in a single test class D OXA-48 carbapenemase producers. In this study, we evaluated a new phenotypic test, the OXA-48 disk test, which is based on an imipenem disk and two blank disks adjacent to the imipenem disk, loa...

OBJECTIVES Plasmid-mediated AmpC β-lactamases (PMABLs) and carbapenemases are emerging groups of antimicrobial-resistance determinants. The aims of the study were to evaluate the occurrence of PMABLs and carbapenemases in clinical isolates of Klebsiella pneumoniae and compare the test performance of various phenotypic methods for detection of these enzymes in Iran. METHODS A total of 100 K. p...

Staphylococcus aureus and Staphylococcus saprophyticus are the most common and most important staphylococcal species associated with urinary tract infections. The objective of the present study was to compare and to evaluate the accuracy of four phenotypic methods for the detection of beta-lactamase production in Staphylococcus spp. Seventy-three strains produced a halo with a diameter ≤28mm (p...

A total of 87 Acinetobacter baumannii nonrepetitive consecutive clinical isolates were tested for the presence of metallo-beta-lactamases (MBLs). Results of phenotypic assays (MBL Etest, imipenem/imipenem-EDTA combined-disk test, and imipenem/EDTA double-disk synergy test) were negative in all cases, but molecular testing revealed the presence of two bla(VIM-1)-carrying isolates. One isolate ha...

BACKGROUND We evaluated the combined use of the modified Hodge test (MHT) and carbapenemase inhibition test (CIT) using phenylboronic acid (PBA) and EDTA to detect carbapenemase-producing Enterobacteriaceae (CPE) and metallo-β-lactamase (MBL)-producing Pseudomonas spp. METHODS A total of 49 isolates of CPE (15 Klebsiella pneumoniae carbapenemase [KPC], 5 Guiana extended-spectrum β-lactamase [...