The modified Hodge test has an excellent sensitivity for detecting enterobacterial isolates producing Ambler class A (KPC) and class D (OXA-48) carbapenemases. Its sensitivity is low for NDM-1 producers (50%) but is increased to 85.7% by adding ZnSO(4) (100 μg/ml) in the culture medium. However, this test has a low specificity and is time-consuming.

The performance of a microarray for the detection of extended-spectrum beta-lactamases was determined on a collection of 638 highly resistant members of the family Enterobacteriaceae collected from patients in 18 hospitals in The Netherlands. The microarray had a significantly higher specificity than the phenotypic assays. It also detects carbapenemases and characterizes the resistance genes, p...

Carbapenem-resistant Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, and Acinetobacter baumannii were isolated from a single patient, each producing different carbapenemases (NDM-1, KPC-2, IMP, and OXA-23, respectively). The NDM-1-producing E. coli strain was preceded by a clonally related carbapenem-susceptible strain a month earlier, suggesting in vivo acquisition of blaNDM-1.

Carbapenems, 'last resort' antibiotics for many bacterial infections, can now be broken down by several class A β-lactamases (i.e. carbapenemases). Here, carbapenemase activity is predicted through QM/MM dynamics simulations of acyl-enzyme deacylation, requiring only the 3D structure of the apo-enzyme. This may assist in anticipating resistance and future antibiotic design.

Ceftazidime-avibactam is the first antimicrobial approved by the U.S. FDA for the treatment of carbapenem-resistant Enterobacteriaceae. Avibactam, a non-β-lactam β-lactamase inhibitor, inactivates class A serine carbapenemases, including Klebsiella pneumoniae carbapenemase (KPC). We report a KPC-producing K. pneumoniae isolate resistant to ceftazidime-avibactam (MIC, 32/4 μg/ml) from a patient ...

OXA-48-type carbapenem-hydrolysing class D β-lactamases are increasingly reported in enterobacterial species. To date, six OXA-48-like variants have been identified, with OXA-48 being the most widespread. They differ by a few amino acid substitutions or deletions (one to five amino acids). The enzymes hydrolyse penicillins at a high level and carbapenems at a low level, sparing broad-spectrum c...

BACKGROUND BAL30376 combines the siderophore monobactam BAL19764 (Syn/PTX 2416) with the bridged monobactam BAL29880 to inhibit AmpC enzymes and with clavulanate to inhibit extended-spectrum β-lactamases (ESBLs). We tested BAL30376 and its components versus isolates and laboratory strains of Enterobacteriaceae and non-fermenters. METHODS MICs were determined on Mueller-Hinton agar supplemente...

Carbapenemases are bacterial enzymes that hydrolyze carbapenems, a group of last-resort β-lactam antibiotics used for treatment of severe bacterial infections. They belong to three β-lactamase classes based amino acid sequence (A, B, and D). The aim of this study was to elucidate occurrence, diversity and functionality of carbapenemase-encoding genes in soil microbiota by functional metagenomic...

Carbapenem-resistant Acinetobacter baumannii (CRAb) is emerging worldwide as a public health problem in various settings. The aim of this study was to investigate the prevalence of CRAb isolates in Italy and to characterize their resistance mechanisms and genetic relatedness. A countrywide cross-sectional survey was carried out at 25 centers in mid-2011. CRAb isolates were reported from all par...