NDM-8 Metallo-β-Lactamase in a Multidrug-Resistant Escherichia coli Strain Isolated in Nepal

Abstract

A novel metallo-␤-lactamase, NDM-8, was identified in a multidrug-resistant Escherichia coli isolate, IOMTU11 (NCGM37), obtained from the respiratory tract of a patient in Nepal. The amino acid sequence of NDM-8 has substitutions at positions 130 (Asp to Gly) and 154 (Met to Leu) compared with NDM-1. NDM-8 showed enzymatic activities against ␤-lactams similar to those of NDM-1.

NDM-12, a Novel New Delhi Metallo-β-Lactamase Variant from a Carbapenem-Resistant Escherichia coli Clinical Isolate in Nepal

“…The lower k cat /K m ratios were likely to be caused by the lower k cat values of NDM-12 compared with those of NDM-1, as the values of NDM-12 were 11.4 to 73.6% of those of NDM-1 ( Table 2). The profiles of enzymatic activities of NDM-1 except for cefoxitin were similar to those of NDM-1 that we reported previously (29). The k cat /K m ratio for cefoxitin in Table 2 was 10-fold higher than that in our previous study (see Table 2 in reference 29).…”

“…Residue 95 is located in ␣1 on the protein surface, and the amino acid substitution at position 95 affected the k cat values of NDM-3 (40). The substitution at position 130 (Met to Leu) showed increased hydrolytic activity toward carbapenems and several cephalosporins compared to NDM-1 (24,29). This is the first report describing NDM-12-producing E. coli in Nepal.…”

“…NDM-1 was initially isolated from Klebsiella pneumoniae and Escherichia coli in 2008 in Sweden (11). Subsequently, at least 11 NDM variants (www.lahey.org /studies) have been reported in several countries (4,(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29).…”

Identification of a Novel NDM Variant, NDM-13, from a Multidrug-Resistant Escherichia coli Clinical Isolate in Nepal

“…NDM-13 with the D95N and M154L substitutions did not show increased hydrolytic activity against the tested carbapenems, cephalosporins, and penicillins, except for cefotaxime. Among the known NDM variants (NDM-1 to NDM-13), amino acid substitutions were observed at 13 (12,17,28), although they are not located at the active site of NDM-1 or in amino acid residues that bind to zinc ions (34,35). The effects of the remaining 10 substitutions on hydrolyzing activity have not yet been reported.…”

Rapid Detection of New Delhi Metallo-β-Lactamase Gene and Variants Coding for Carbapenemases with Different Activities by Use of a PCR-Based In Vitro Protein Expression Method

“…At the same time, along with its spread, variants of NDM-1 are emerging. Until now, 10 NDM variants have been found (7)(8)(9)(10)(11)(12)(13); also NDM-9 [nucleotide sequence no. KC999080.1] and NDM-10 [nucleotide sequence accession no.…”