Occurrence of a new metallo-β-lactamase IMP-4 carried on a conjugative plasmid in Citrobacter youngae from the People's Republic of China

Abstract

During the course of an antimicrobial resistance surveillance programme in Guangzhou, the People's Republic of China, single strains of Citrobacter youngae and Pseudomonas aeruginosa were identified which were resistant to imipenem and found to carry the carbapenemase gene bla IMP . PCR screening of the citrobacter strain with specific primers for the bla IMP type genes gave a 587-bp product which when sequenced gave 100% homology with the bla IMPÀ4 sequence reported recently from Acinetobacter spp. The determinant in the C. youngae strain was found to be located on a 156-kb plasmid capable of transfer to Escherichia coli UB1637 by conjugation. Sequencing of the bla IMPÀ4 open reading frame in the C. youngae strain and adjacent sequences not only confirmed the presence of bla IMPÀ4 but also identified that a conserved core site found within the 59-bp element of integrons was present and the same as the one described in the only other occurrence of bla IMPÀ4 in Acinetobacter spp. isolated from an intensive care unit in Hong Kong. This is the second report of transferable carbapenemase genes in Enterobacteriacae outside of Japan and the first in the People's Republic of China. Under the selective pressure of carbapenems and extended spectrum cephalosporins use we might expect this gene to spread and widespread surveillance should be instituted. ß FEMS Microbiology Letters 194 (2001) 53^57 www.fems-microbiology.org Fig. 1. Comparison of the deduced nucleotide sequences of the di¡erent bla IMP genes, identical residues to bla IMPÀ1 are indicated by a dash. P.M. Hawkey et al. / FEMS Microbiology Letters 194 (2001) 53^57

Detection of the novel IMP-38 among carbapenemase-producing Enterobacteriaceae in a university hospital, China

“…IMP-4, the first MBL found in a plasmid from a C. youngae isolate in 2001 in China, now appears to be the most dominant variant in China [13]. In the present study, we detected twenty IMP-producing isolates, including eleven IMP-4-positive and nine IMP-38-positive isolates.…”

Detection of plasmid-mediated IMP-1 metallo-β-lactamase and quinolone resistance determinants in an ertapenem-resistant Enterobacter cloacae isolate

“…IMP-producing Enterobacteriaceae were mainly reported from Japan, Australia, and Taiwan region of China. Production of IMP in Enterobacteriaceae was rare in mainland China, including IMP-4 in C. youngae and K. pneumoniae (Hawkey et al, 2001;Mendes et al, 2008). In this study, we detected bla IMP-1 and qnrS1 genes along with alternations in gyrA and parC in a clinical isolate of ertapenem-resistant E. cloacae.…”

“…In China, there were only two reports on the production of IMP in Enterobacteriaceae. An IMP-4-producing Citrobacter youngae was isolated from Guangzhou in 2001 (Hawkey et al, 2001) and an IMP-4-producing K. pneumoniae from Wuhan in 2008 (Mendes et al, 2008).…”

Characteristics and management of Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemase in a tertiary hospital

“…Since then, IMP-type enzymes has been described worldwide, and endemicity of IMP-type enzymes has been reported in in many countries 35 . However, Most MBL producers are hospital acquired and multidrug-resistant K. pneumoniae 36 . The first metallo-β-lactamase reported from China was IMP-4, which was detected on a plasmid in C.youngae and reported in a 2001 publication 36 , followed by reports of IMP-1 and IMP-9 in a P. aeruginosa isolate 37,38 .…”