Beta-Lactamase Database (BLDB) is a comprehensive, manually curated public resource providing up-to-date structural and functional information focused on this superfamily of enzymes with a great impact on antibiotic resistance. All the enzymes reported and characterised in the literature are presented according to the class (A, B, C and D), family and subfamily to which they belong. All three-dimensional structures of β-lactamases present in the Protein Data Bank are also shown. The characterisation of representative mutants and hydrolytic profiles (kinetics) completes the picture and altogether these four elements constitute the essential foundation for a better understanding of the structure-function relationship within this enzymes family. BLDB can be queried using different protein- and nucleotide-based BLAST searches, which represents a key feature of particular importance in the context of the surveillance of the evolution of the antibiotic resistance. BLDB is available online at http://bldb.eu without any registration and supports all modern browsers.

To rapidly identify carbapenemase producers in Enterobacteriaceae, we developed the Carba NP test. The test uses isolated bacterial colonies and is based on in vitro hydrolysis of a carbapenem, imipenem. It was 100% sensitive and specific compared with molecular-based techniques. This rapid (<2 hours), inexpensive technique may be implemented in any laboratory.

The emergence of one of the most recently described carbapenemases, namely, the New Delhi metallo-lactamase (NDM-1), constitutes a critical and growingly important medical issue. This resistance trait compromises the efficacy of almost all lactams (except aztreonam), including the last resort carbapenems. Therapeutical options may remain limited mostly to colistin, tigecycline, and fosfomycin. The main known reservoir of NDM producers is the Indian subcontinent whereas a secondary reservoir seems to have established the Balkans regions and the Middle East. Although the spread ofblaNDM-like genes (several variants) is derived mostly by conjugative plasmids in Enterobacteriaceae, this carbapenemase has also been identified inP. aeruginosaandAcinetobacterspp.Acinetobactersp. may play a pivotal role for spreadingblaNDMgenes for its natural reservoir to Enterobacteriaceae. Rapid diagnostic techniques (Carba NP test) and screening of carriers are the cornerstone to try to contain this outbreak which threatens the efficacy of the modern medicine.

Genetic features associated with the bla _NDM-1 gene were investigated in 6 Escherichia coli , 7 Klebsiella pneumoniae , 1 Citrobacter freundii , 1 Proteus mirabilis , and 1 Providencia stuartii isolate of worldwide origin. Clonal diversity was observed for both E. coli and K. pneumoniae . The bla _NDM-1 gene was carried by different plasmid types (IncA/C, IncF, IncL/M, or untypeable) and was likely chromosome borne in two isolates. The bla _NDM-1 plasmids coharbored a variety of resistance determinants, including β-lactamase genes, quinolone resistance genes, and 16S RNA methylase genes.

A biochemical test (Carba NP test II) was developed to identify carbapenemase production in Enterobacteriaceae and Pseudomonas spp. and to discriminate between the different types of carbapenemases (classes A, B, and D). It is based on the detection of the acidification resulting from imipenem hydrolysis, coupled with tazobactam and EDTA as inhibitors. This is an easy and reliable technique (100% sensitivity and specificity) for detection of not only carbapenemase activity but also carbapenemase types in Enterobacteriaceae and Pseudomonas aeruginosa .